Merge branch 'master' into docs_ci

144 files changed, 5661 insertions, 3439 deletions

diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 87acb5ef..72d02f2b 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,7 +1,6 @@
 [bumpversion]
-current_version = 41.0.1
+current_version = 46.4.0
 commit = True
 tag = True
 
 [bumpversion:file:setup.cfg]
-
diff --git a/.flake8 b/.flake8
new file mode 100644
index 00000000..c6580616
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,12 @@
+[flake8]
+exclude=
+    .tox
+    setuptools/_vendor,
+    pkg_resources/_vendor
+ignore =
+    # W503 violates spec https://github.com/PyCQA/pycodestyle/issues/513
+    W503
+    # W504 has issues https://github.com/OCA/maintainer-quality-tools/issues/545
+    W504
+    setuptools/site-patch.py F821
+    setuptools/py*compat.py F811
diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
new file mode 100644
index 00000000..27de01d0
--- /dev/null
+++ b/.github/FUNDING.yml
@@ -0,0 +1 @@
+tidelift: pypi/setuptools
diff --git a/.github/ISSUE_TEMPLATE/setuptools-warns-about-python-2-incompatibility.md b/.github/ISSUE_TEMPLATE/setuptools-warns-about-python-2-incompatibility.md
new file mode 100644
index 00000000..2f5fe53d
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/setuptools-warns-about-python-2-incompatibility.md
@@ -0,0 +1,53 @@
+---
+name: Setuptools warns about Python 2 incompatibility
+about: Report the issue where setuptools 45 or later stops working on Python 2
+title: Incompatible install in (summarize your environment)
+labels: Python 2
+assignees: ''
+
+---
+
+<!--
+
+Please DO NOT SUBMIT this template without first investigating the issue and answering the questions below. This template is intended mainly for developers of systems and not for end users. If you are an end user experiencing the warning, please work with your system maintainers (starting with the project you're trying to use) to report the issue.
+
+If you did not intend to use this template, but only meant to file a blank issue, just hit the back button and click "Open a blank issue".
+
+It's by design that Setuptools 45 and later will stop working on Python 2. To ease the transition, Setuptools 45 was released to continue to have Python 2 compatibility, but emit a strenuous warning that it will stop working.
+
+In most cases, using pip 9 or later to install Setuptools from PyPI or any index supporting the Requires-Python metadata will do the right thing and install Setuptools 44.x on Python 2.
+
+If you've come to file an issue, it's probably because some process managed to bypass these protections.
+
+Your first course of action should be to reason about how you managed to get an unsupported version of Setuptools on Python 2. Please complete the sections below and provide any other detail about your environment that will help us help you.
+
+-->
+
+## Prerequisites
+
+<!-- These are the recommended workarounds for the issue. Please
+try them first. -->
+
+- [ ] Python 2 is required for this application.
+- [ ] I maintain the software that installs Setuptools (if not, please contact that project).
+- [ ] Setuptools installed with pip 9 or later.
+- [ ] Pinning Setuptools to `setuptools<45` in the environment was unsuccessful.
+
+## Environment Details
+
+- Operating System and version:
+- Python version:
+- Python installed how:
+- Virtualenv version (if using virtualenv): n/a
+
+Command(s) used to install setuptools (and output):
+
+```
+```
+
+Output of `pip --version` when installing setuptools:
+
+```
+```
+
+## Other notes
diff --git a/.github/workflows/python-tests.yml b/.github/workflows/python-tests.yml
new file mode 100644
index 00000000..e3663cf0
--- /dev/null
+++ b/.github/workflows/python-tests.yml
@@ -0,0 +1,102 @@
+name: >-
+  👷
+  Test suite
+
+on:
+  push:
+  pull_request:
+  schedule:
+  - cron: 1 0 * * *  # Run daily at 0:01 UTC
+
+jobs:
+  tests:
+    name: >-
+      ${{ matrix.python-version }}
+      /
+      ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      # max-parallel: 5
+      matrix:
+        python-version:
+        - 3.8
+        - pypy3
+        - 3.7
+        - 3.6
+        - 3.5
+        os:
+        - ubuntu-latest
+        - ubuntu-16.04
+        - macOS-latest
+        # - windows-2019
+        # - windows-2016
+
+    env:
+      NETWORK_REQUIRED: 1
+      TOX_PARALLEL_NO_SPINNER: 1
+      TOXENV: python
+
+    steps:
+    - uses: actions/checkout@master
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v1.1.1
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Log Python version
+      run: >-
+        python --version
+    - name: Log Python location
+      run: >-
+        which python
+    - name: Log Python env
+      run: >-
+        python -m sysconfig
+    - name: Pip cache
+      uses: actions/cache@v1
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ hashFiles('setup.cfg') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-
+          ${{ runner.os }}-
+    - name: Upgrade pip/setuptools/wheel
+      run: >-
+        python
+        -m pip install
+        --disable-pip-version-check
+        --upgrade
+        pip setuptools wheel
+    - name: Install tox
+      run: >-
+        python -m pip install --upgrade tox tox-venv
+    - name: Log installed dists
+      run: >-
+        python -m pip freeze --all
+    - name: Adjust TOXENV for PyPy
+      if: startsWith(matrix.python-version, 'pypy')
+      run: >-
+        echo "::set-env name=TOXENV::${{ matrix.python-version }}"
+    - name: Log env vars
+      run: >-
+        env
+
+    - name: Verify that there's no cached Python modules in sources
+      if: >-
+        ! startsWith(matrix.os, 'windows-')
+      run: >-
+        ! grep pyc setuptools.egg-info/SOURCES.txt
+
+    - name: 'Initialize tox envs: ${{ matrix.env.TOXENV }}'
+      run: >-
+        python -m
+        tox
+        --parallel auto
+        --notest
+        --skip-missing-interpreters false
+    - name: Test with tox
+      run: >-
+        python -m
+        tox
+        --parallel auto
+        --
+        --cov
diff --git a/.gitignore b/.gitignore
index 0c272d1c..90ae8050 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,3 +19,4 @@ setuptools.egg-info
 .cache
 .idea/
 .pytest_cache/
+.mypy_cache/
diff --git a/.readthedocs.yml b/.readthedocs.yml
index 3aef6b6b..cb10a7f9 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,4 +1,6 @@
 python:
   version: 3
-  requirements_file: docs/requirements.txt
+  extra_requirements:
+  - docs
   pip_install: false
+  requirements: docs/requirements.txt
diff --git a/.travis.yml b/.travis.yml
index 074e86e9..25cfb6e4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,43 +6,26 @@ jobs:
   include:
   - &latest_py2
     python: 2.7
+    env: TOXENV=py27
   - <<: *latest_py2
-    env: LANG=C
-  - python: pypy2.7-6.0.0
+    env: LANG=C TOXENV=py27
+  - python: pypy3
     env: DISABLE_COVERAGE=1  # Don't run coverage on pypy (too slow).
-  - python: pypy3.5-6.0.0
-    env: DISABLE_COVERAGE=1
-  - python: 3.4
   - python: 3.5
-  - &default_py
-    python: 3.6
+  - python: 3.6
+  - python: 3.7
   - &latest_py3
-    python: 3.7
+    python: 3.8
   - <<: *latest_py3
     env: LANG=C
   - python: 3.8-dev
   - <<: *latest_py3
     env: TOXENV=docs DISABLE_COVERAGE=1
-  - <<: *default_py
-    stage: deploy (to PyPI for tagged commits)
-    if: tag IS present
-    install: skip
-    script: skip
-    after_success: true
-    before_deploy:
-      - python bootstrap.py
-      - "! grep pyc setuptools.egg-info/SOURCES.txt"
-    deploy:
-      provider: pypi
-      on:
-        tags: true
-        all_branches: true
-      user: jaraco
-      password:
-        secure: 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
-      distributions: release
-      skip_cleanup: true
-      skip_upload_docs: true
+  allow_failures:
+  # suppress failures due to pypa/setuptools#2000
+  - python: pypy3
+  - <<: *latest_py3
+    env: TOXENV=docs DISABLE_COVERAGE=1
 
 cache: pip
 
@@ -57,8 +40,6 @@ install:
 - pip freeze --all
 - env
 
-# update egg_info based on setup.py in checkout
-- python bootstrap.py
 - "! grep pyc setuptools.egg-info/SOURCES.txt"
 
 script:
diff --git a/CHANGES.rst b/CHANGES.rst
index 9da22537..ea667028 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,230 @@
+v46.4.0
+-------
+
+* #1753: ``attr:`` now extracts variables through rudimentary examination of the AST,
+  thereby supporting modules with third-party imports. If examining the AST
+  fails to find the variable, ``attr:`` falls back to the old behavior of
+  importing the module. Works on Python 3 only.
+
+
+v46.3.1
+-------
+
+No significant changes.
+
+
+v46.3.0
+-------
+
+* #2089: Package index functionality no longer attempts to remove an md5 fragment from the index URL. This functionality, added for distribute #163 is no longer relevant.
+* #2041: Preserve file modes during pkg files copying, but clear read only flag for target afterwards.
+* #2105: Filter ``2to3`` deprecation warnings from ``TestDevelop.test_2to3_user_mode``.
+
+
+v46.2.0
+-------
+
+* #2040: Deprecated the ``bdist_wininst`` command. Binary packages should be built as wheels instead.
+* #2062: Change 'Mac OS X' to 'macOS' in code.
+* #2075: Stop recognizing files ending with ``.dist-info`` as distribution metadata.
+* #2086: Deprecate 'use_2to3' functionality. Packagers are encouraged to use single-source solutions or build tool chains to manage conversions outside of setuptools.
+* #1698: Added documentation for ``build_meta`` (a bare minimum, not completed).
+* #2082: Filter ``lib2to3`` ``PendingDeprecationWarning`` and ``DeprecationWarning`` in tests,
+  because ``lib2to3`` is `deprecated in Python 3.9 <https://bugs.python.org/issue40360>`_.
+
+
+v46.1.3
+-------
+
+No significant changes.
+
+
+v46.1.2
+-------
+
+* #1458: Added template for reporting Python 2 incompatibilities.
+
+
+v46.1.1
+-------
+
+No significant changes.
+
+
+v46.1.0
+-------
+
+* #308: Allow version number normalization to be bypassed by wrapping in a 'setuptools.sic()' call.
+* #1424: Prevent keeping files mode for package_data build. It may break a build if user's package data has read only flag.
+* #1431: In ``easy_install.check_site_dir``, ensure the installation directory exists.
+* #1563: In ``pkg_resources`` prefer ``find_spec`` (PEP 451) to ``find_module``.
+
+Incorporate changes from v44.1.0:
+
+* #1704: Set sys.argv[0] in setup script run by build_meta.__legacy__
+* #1959: Fix for Python 4: replace unsafe six.PY3 with six.PY2
+* #1994: Fixed a bug in the "setuptools.finalize_distribution_options" hook that lead to ignoring the order attribute of entry points managed by this hook.
+
+
+v44.1.0
+-------
+
+* #1704: Set sys.argv[0] in setup script run by build_meta.__legacy__
+* #1959: Fix for Python 4: replace unsafe six.PY3 with six.PY2
+* #1994: Fixed a bug in the "setuptools.finalize_distribution_options" hook that lead to ignoring the order attribute of entry points managed by this hook.
+
+
+v46.0.0
+-------
+
+* #65: Once again as in 3.0, removed the Features feature.
+* #1890: Fix vendored dependencies so importing ``setuptools.extern.some_module`` gives the same object as ``setuptools._vendor.some_module``. This makes Metadata picklable again.
+* #1899: Test suite now fails on warnings.
+* #2011: Fix broken link to distutils docs on package_data
+* #1991: Include pkg_resources test data in sdist, so tests can be executed from it.
+
+
+v45.3.0
+-------
+
+* #1557: Deprecated eggsecutable scripts and updated docs.
+* #1904: Update msvc.py to use CPython 3.8.0 mechanism to find msvc 14+
+
+
+v45.2.0
+-------
+
+* #1905: Fixed defect in _imp, introduced in 41.6.0 when the 'tests' directory is not present.
+* #1941: Improve editable installs with PEP 518 build isolation:
+
+  * The ``--user`` option is now always available. A warning is issued if the user site directory is not available.
+  * The error shown when the install directory is not in ``PYTHONPATH`` has been turned into a warning.
+* #1981: Setuptools now declares its ``tests`` and ``docs`` dependencies in metadata (extras).
+* #1985: Add support for installing scripts in environments where bdist_wininst is missing (i.e. Python 3.9).
+* #1968: Add flake8-2020 to check for misuse of sys.version or sys.version_info.
+
+
+v45.1.0
+-------
+
+* #1458: Add minimum sunset date and preamble to Python 2 warning.
+* #1704: Set sys.argv[0] in setup script run by build_meta.__legacy__
+* #1974: Add Python 3 Only Trove Classifier and remove universal wheel declaration for more complete transition from Python 2.
+
+
+v45.0.0
+-------
+
+* #1458: Drop support for Python 2. Setuptools now requires Python 3.5 or later. Install setuptools using pip >=9 or pin to Setuptools <45 to maintain 2.7 support.
+* #1959: Fix for Python 4: replace unsafe six.PY3 with six.PY2
+
+
+v44.0.0
+-------
+
+* #1908: Drop support for Python 3.4.
+
+
+v43.0.0
+-------
+
+* #1634: Include ``pyproject.toml`` in source distribution by default. Projects relying on the previous behavior where ``pyproject.toml`` was excluded by default should stop relying on that behavior or add ``exclude pyproject.toml`` to their MANIFEST.in file.
+* #1927: Setuptools once again declares 'setuptools' in the ``build-system.requires`` and adds PEP 517 build support by declaring itself as the ``build-backend``. It additionally specifies ``build-system.backend-path`` to rely on itself for those builders that support it.
+
+
+v42.0.2
+-------
+
+* #1921: Fix support for easy_install's ``find-links`` option in ``setup.cfg``.
+* #1922: Build dependencies (setup_requires and tests_require) now install transitive dependencies indicated by extras.
+
+
+v42.0.1
+-------
+
+* #1918: Fix regression in handling wheels compatibility tags.
+
+
+v42.0.0
+-------
+
+* #1830, #1909: Mark the easy_install script and setuptools command as deprecated, and use `pip <https://pip.pypa.io/en/stable/>`_ when available to fetch/build wheels for missing ``setup_requires``/``tests_require`` requirements, with the following differences in behavior:
+   * support for ``python_requires``
+   * better support for wheels (proper handling of priority with respect to PEP 425 tags)
+   * PEP 517/518 support
+   * eggs are not supported
+   * no support for the ``allow_hosts`` easy_install option (``index_url``/``find_links`` are still honored)
+   * pip environment variables are honored (and take precedence over easy_install options)
+* #1898: Removed the "upload" and "register" commands in favor of `twine <https://pypi.org/p/twine>`_.
+* #1767: Add support for the ``license_files`` option in ``setup.cfg`` to automatically
+  include multiple license files in a source distribution.
+* #1829: Update handling of wheels compatibility tags:
+  * add support for manylinux2010
+  * fix use of removed 'm' ABI flag in Python 3.8 on Windows
+* #1861: Fix empty namespace package installation from wheel.
+* #1877: Setuptools now exposes a new entry point hook "setuptools.finalize_distribution_options", enabling plugins like `setuptools_scm <https://pypi.org/project/setuptools_scm>`_ to configure options on the distribution at finalization time.
+
+
+v41.6.0
+-------
+
+* #479: Replace usage of deprecated ``imp`` module with local re-implementation in ``setuptools._imp``.
+
+
+v41.5.1
+-------
+
+* #1891: Fix code for detecting Visual Studio's version on Windows under Python 2.
+
+
+v41.5.0
+-------
+
+* #1811: Improve Visual C++ 14.X support, mainly for Visual Studio 2017 and 2019.
+* #1814: Fix ``pkg_resources.Requirement`` hash/equality implementation: take PEP 508 direct URL into account.
+* #1824: Fix tests when running under ``python3.10``.
+* #1878: Formally deprecated the ``test`` command, with the recommendation that users migrate to ``tox``.
+* #1860: Update documentation to mention the egg format is not supported by pip and dependency links support was dropped starting with pip 19.0.
+* #1862: Drop ez_setup documentation: deprecated for some time (last updated in 2016), and still relying on easy_install (deprecated too).
+* #1868: Drop most documentation references to (deprecated) EasyInstall.
+* #1884: Added a trove classifier to document support for Python 3.8.
+* #1886: Added Python 3.8 release to the Travis test matrix.
+
+
+v41.4.0
+-------
+
+* #1847: In declarative config, now traps errors when invalid ``python_requires`` values are supplied.
+
+
+v41.3.0
+-------
+
+* #1690: When storing extras, rely on OrderedSet to retain order of extras as indicated by the packager, which will also be deterministic on Python 2.7 (with PYTHONHASHSEED unset) and Python 3.6+.
+* #1858: Fixed failing integration test triggered by 'long_description_content_type' in packaging.
+
+
+v41.2.0
+-------
+
+* #479: Remove some usage of the deprecated ``imp`` module.
+* #1565: Changed html_sidebars from string to list of string as per
+  https://www.sphinx-doc.org/en/master/changes.html#id58
+
+
+v41.1.0
+-------
+
+* #1697: Moved most of the constants from setup.py to setup.cfg
+* #1749: Fixed issue with the PEP 517 backend where building a source distribution would fail if any tarball existed in the destination directory.
+* #1750: Fixed an issue with PEP 517 backend where wheel builds would fail if the destination directory did not already exist.
+* #1756: Force metadata-version >= 1.2. when project urls are present.
+* #1769: Improve ``package_data`` check: ensure the dictionary values are lists/tuples of strings.
+* #1788: Changed compatibility fallback logic for ``html.unescape`` to avoid accessing ``HTMLParser.unescape`` when not necessary. ``HTMLParser.unescape`` is deprecated and will be removed in Python 3.9.
+* #1790: Added the file path to the error message when a ``UnicodeDecodeError`` occurs while reading a metadata file.
+* #1776: Use license classifiers rather than the license field.
+
+
 v41.0.1
 -------
 
diff --git a/MANIFEST.in b/MANIFEST.in
index 16d60e5f..128ae280 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -4,6 +4,7 @@ recursive-include setuptools/tests *.html
 recursive-include docs *.py *.txt *.conf *.css *.css_t Makefile indexsidebar.html
 recursive-include setuptools/_vendor *.py *.txt
 recursive-include pkg_resources *.py *.txt
+recursive-include pkg_resources/tests/data *
 include *.py
 include *.rst
 include MANIFEST.in
diff --git a/README.rst b/README.rst
index dac8a468..9cbf7b86 100644
--- a/README.rst
+++ b/README.rst
@@ -1,8 +1,13 @@
 .. image:: https://img.shields.io/pypi/v/setuptools.svg
-   :target: https://pypi.org/project/setuptools
+   :target: `PyPI link`_
 
-.. image:: https://img.shields.io/readthedocs/setuptools/latest.svg
-    :target: https://setuptools.readthedocs.io
+.. image:: https://img.shields.io/pypi/pyversions/setuptools.svg
+   :target: `PyPI link`_
+
+.. _PyPI link: https://pypi.org/project/setuptools
+
+.. image:: https://dev.azure.com/jaraco/setuptools/_apis/build/status/pypa.setuptools?branchName=master
+   :target: https://dev.azure.com/jaraco/setuptools/_build/latest?definitionId=1&branchName=master
 
 .. image:: https://img.shields.io/travis/pypa/setuptools/master.svg?label=Linux%20CI&logo=travis&logoColor=white
    :target: https://travis-ci.org/pypa/setuptools
@@ -10,14 +15,15 @@
 .. image:: https://img.shields.io/appveyor/ci/pypa/setuptools/master.svg?label=Windows%20CI&logo=appveyor&logoColor=white
    :target: https://ci.appveyor.com/project/pypa/setuptools/branch/master
 
+.. image:: https://img.shields.io/readthedocs/setuptools/latest.svg
+    :target: https://setuptools.readthedocs.io
+
 .. image:: https://img.shields.io/codecov/c/github/pypa/setuptools/master.svg?logo=codecov&logoColor=white
    :target: https://codecov.io/gh/pypa/setuptools
 
 .. image:: https://tidelift.com/badges/github/pypa/setuptools?style=flat
    :target: https://tidelift.com/subscription/pkg/pypi-setuptools?utm_source=pypi-setuptools&utm_medium=readme
 
-.. image:: https://img.shields.io/pypi/pyversions/setuptools.svg
-
 See the `Installation Instructions
 <https://packaging.python.org/installing/>`_ in the Python Packaging
 User's Guide for instructions on installing, upgrading, and uninstalling
@@ -34,8 +40,17 @@ To report a security vulnerability, please use the
 Tidelift will coordinate the fix and disclosure.
 
 
+For Enterprise
+==============
+
+Available as part of the Tidelift Subscription.
+
+Setuptools and the maintainers of thousands of other packages are working with Tidelift to deliver one enterprise subscription that covers all of the open source you use.
+
+`Learn more <https://tidelift.com/subscription/pkg/pypi-setuptools?utm_source=pypi-setuptools&utm_medium=referral&utm_campaign=github>`_.
+
 Code of Conduct
----------------
+===============
 
 Everyone interacting in the setuptools project's codebases, issue trackers,
 chat rooms, and mailing lists is expected to follow the
diff --git a/appveyor.yml b/appveyor.yml
index 08818069..de4e6c66 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -7,10 +7,19 @@ environment:
   CODECOV_ENV: APPVEYOR_JOB_NAME
 
   matrix:
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      APPVEYOR_JOB_NAME: "python35-x64-vs2015"
+      PYTHON: "C:\\Python35-x64"
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      APPVEYOR_JOB_NAME: "python35-x64-vs2017"
+      PYTHON: "C:\\Python35-x64"
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      APPVEYOR_JOB_NAME: "python35-x64-vs2019"
+      PYTHON: "C:\\Python35-x64"
     - APPVEYOR_JOB_NAME: "python36-x64"
       PYTHON: "C:\\Python36-x64"
-    - APPVEYOR_JOB_NAME: "python27-x64"
-      PYTHON: "C:\\Python27-x64"
+    - APPVEYOR_JOB_NAME: "python37-x64"
+      PYTHON: "C:\\Python37-x64"
 
 install:
   # symlink python from a directory with a space
@@ -28,7 +37,6 @@ test_script:
   - python -m pip install --disable-pip-version-check --upgrade pip setuptools wheel
   - pip install --upgrade tox tox-venv virtualenv
   - pip freeze --all
-  - python bootstrap.py
   - tox -- --cov
 
 after_test:
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
new file mode 100644
index 00000000..ee772682
--- /dev/null
+++ b/azure-pipelines.yml
@@ -0,0 +1,81 @@
+# Create the project in Azure with:
+# az devops project create --name $name --organization https://dev.azure.com/$org/ --visibility public
+# then configure the pipelines (through web UI)
+
+trigger:
+  branches:
+    include:
+    - '*'
+  tags:
+    include:
+    - '*'
+
+pool:
+  vmImage: $(pool_vm_image)
+
+variables:
+- group: Azure secrets
+- name: pool_vm_image
+  value: Ubuntu-18.04
+
+stages:
+- stage: Test
+  jobs:
+
+  - job: 'Test'
+    strategy:
+      matrix:
+        Bionic Python 3.6:
+          python.version: '3.6'
+        Bionic Python 3.8:
+          python.version: '3.8'
+        Windows:
+          python.version: '3.8'
+          pool_vm_image: vs2017-win2016
+        MacOS:
+          python.version: '3.8'
+          pool_vm_image: macos-10.15
+
+      maxParallel: 4
+
+    steps:
+    - task: UsePythonVersion@0
+      inputs:
+        versionSpec: '$(python.version)'
+        architecture: 'x64'
+
+    - script: python -m pip install tox
+      displayName: 'Install tox'
+
+    - script: |
+        tox -- --junit-xml=test-results.xml
+      displayName: 'run tests'
+
+    - task: PublishTestResults@2
+      inputs:
+        testResultsFiles: '**/test-results.xml'
+        testRunTitle: 'Python $(python.version)'
+      condition: succeededOrFailed()
+
+- stage: Publish
+  dependsOn: Test
+  jobs:
+  - job: 'Publish'
+
+    steps:
+    - task: UsePythonVersion@0
+      inputs:
+        versionSpec: '3.8'
+        architecture: 'x64'
+
+    - script: python -m pip install tox
+      displayName: 'Install tox'
+
+    - script: |
+        tox -e release
+      env:
+        TWINE_PASSWORD: $(PyPI-token)
+        TIDELIFT_TOKEN: $(Tidelift-token)
+      displayName: 'publish to PyPI'
+
+  condition: contains(variables['Build.SourceBranch'], 'tags')
diff --git a/bootstrap.py b/bootstrap.py
index 8c7d7fc3..8fa9e4b5 100644
--- a/bootstrap.py
+++ b/bootstrap.py
@@ -25,6 +25,7 @@ minimal_egg_info = textwrap.dedent("""
     entry_points = setuptools.dist:check_entry_points
 
     [egg_info.writers]
+    PKG-INFO = setuptools.command.egg_info:write_pkg_info
     dependency_links.txt = setuptools.command.egg_info:overwrite_arg
     entry_points.txt = setuptools.command.egg_info:write_entries
     requires.txt = setuptools.command.egg_info:write_requirements
@@ -35,10 +36,11 @@ def ensure_egg_info():
     if os.path.exists('setuptools.egg-info'):
         return
     print("adding minimal entry_points")
-    build_egg_info()
+    add_minimal_info()
+    run_egg_info()
 
 
-def build_egg_info():
+def add_minimal_info():
     """
     Build a minimal egg-info, enough to invoke egg_info
     """
@@ -52,13 +54,6 @@ def run_egg_info():
     cmd = [sys.executable, 'setup.py', 'egg_info']
     print("Regenerating egg_info")
     subprocess.check_call(cmd)
-    print("...and again.")
-    subprocess.check_call(cmd)
-
-
-def main():
-    ensure_egg_info()
-    run_egg_info()
 
 
-__name__ == '__main__' and main()
+__name__ == '__main__' and ensure_egg_info()
diff --git a/changelog.d/1697.change.rst b/changelog.d/1697.change.rst
deleted file mode 100644
index 44818b3c..00000000
--- a/changelog.d/1697.change.rst
+++ /dev/null
@@ -1 +0,0 @@
-Moved most of the constants from setup.py to setup.cfg
diff --git a/changelog.d/1700.change.rst b/changelog.d/1700.change.rst
new file mode 100644
index 00000000..f66046a2
--- /dev/null
+++ b/changelog.d/1700.change.rst
@@ -0,0 +1 @@
+Document all supported keywords by migrating the ones from distutils.
diff --git a/changelog.d/1749.change.rst b/changelog.d/1749.change.rst
deleted file mode 100644
index de678072..00000000
--- a/changelog.d/1749.change.rst
+++ /dev/null
@@ -1 +0,0 @@
-Fixed issue with the PEP 517 backend where building a source distribution would fail if any tarball existed in the destination directory.
diff --git a/changelog.d/1750.change.rst b/changelog.d/1750.change.rst
deleted file mode 100644
index 7a22229e..00000000
--- a/changelog.d/1750.change.rst
+++ /dev/null
@@ -1 +0,0 @@
-Fixed an issue with PEP 517 backend where wheel builds would fail if the destination directory did not already exist.
diff --git a/changelog.d/1756.change.rst b/changelog.d/1756.change.rst
deleted file mode 100644
index 5c908d35..00000000
--- a/changelog.d/1756.change.rst
+++ /dev/null
@@ -1 +0,0 @@
-Forse metadata-version >= 1.2. when project urls are present.
diff --git a/changelog.d/1776.doc.rst b/changelog.d/1776.doc.rst
deleted file mode 100644
index d4f1dbca..00000000
--- a/changelog.d/1776.doc.rst
+++ /dev/null
@@ -1 +0,0 @@
-Use license classifiers rather than the license field.
diff --git a/changelog.d/1788.change.rst b/changelog.d/1788.change.rst
deleted file mode 100644
index d8a49fd4..00000000
--- a/changelog.d/1788.change.rst
+++ /dev/null
@@ -1 +0,0 @@
-Changed compatibility fallback logic for ``html.unescape`` to avoid accessing ``HTMLParser.unescape`` when not necessary. ``HTMLParser.unescape`` is deprecated and will be removed in Python 3.9.
diff --git a/changelog.d/1790.change.rst b/changelog.d/1790.change.rst
deleted file mode 100644
index e4a7998d..00000000
--- a/changelog.d/1790.change.rst
+++ /dev/null
@@ -1,2 +0,0 @@
-Added the file path to the error message when a ``UnicodeDecodeError`` occurs
-while reading a metadata file.
diff --git a/conftest.py b/conftest.py
index 0d7b274c..1746bfb5 100644
--- a/conftest.py
+++ b/conftest.py
@@ -19,6 +19,7 @@ collect_ignore = [
 
 if sys.version_info < (3,):
     collect_ignore.append('setuptools/lib2to3_ex.py')
+    collect_ignore.append('setuptools/_imp.py')
 
 
 if sys.version_info < (3, 6):
diff --git a/docs/_templates/indexsidebar.html b/docs/_templates/indexsidebar.html
index 504de6b0..d803b8a3 100644
--- a/docs/_templates/indexsidebar.html
+++ b/docs/_templates/indexsidebar.html
@@ -1,3 +1,10 @@
+<h3 class="donation">For Enterprise</h3>
+
+<p>
+Professionally-supported {{ project }} is available with the
+<a href="https://tidelift.com/subscription/pkg/pypi-{{ project }}?utm_source=pypi-{{ project }}&utm_medium=referral">Tidelift Subscription</a>.
+</p>
+
 <h3>Download</h3>
 
 <p>Current version: <b>{{ version }}</b></p>
@@ -6,10 +13,3 @@
 <h3>Questions? Suggestions? Contributions?</h3>
 
 <p>Visit the <a href="{{ package_url }}">Project page</a> </p>
-
-<h3 class="donation">Professional support</h3>
-
-<p>
-Professionally-supported {{ project }} is available with the
-<a href="https://tidelift.com/subscription/pkg/pypi-{{ project }}?utm_source=pypi-{{ project }}&utm_medium=readme">Tidelift Subscription</a>.
-</p>
diff --git a/docs/build_meta.txt b/docs/build_meta.txt
new file mode 100644
index 00000000..ef9fb2ac
--- /dev/null
+++ b/docs/build_meta.txt
@@ -0,0 +1,89 @@
+=======================================
+Build System Support
+=======================================
+
+What is it?
+-------------
+
+Python packaging has come `a long way <https://www.bernat.tech/pep-517-518/>`_.
+
+The traditional ``setuptools`` way of packgaging Python modules
+uses a ``setup()`` function within the ``setup.py`` script. Commands such as
+``python setup.py bdist`` or ``python setup.py bdist_wheel`` generate a 
+distribution bundle and ``python setup.py install`` installs the distribution. 
+This interface makes it difficult to choose other packaging tools without an 
+overhaul. Because ``setup.py`` scripts allowed for arbitrary execution, it
+proved difficult to provide a reliable user experience across environments
+and history.
+
+`PEP 517 <https://www.python.org/dev/peps/pep-0517/>`_ therefore came to
+rescue and specified a new standard to 
+package and distribute Python modules. Under PEP 517:
+
+    a ``pyproject.toml`` file is used to specify what program to use
+    for generating distribution. 
+
+    Then, two functions provided by the program, ``build_wheel(directory: str)`` 
+    and ``build_sdist(directory: str)`` create the distribution bundle at the 
+    specified ``directory``. The program is free to use its own configuration 
+    script or extend the ``.toml`` file. 
+
+    Lastly, ``pip install *.whl`` or ``pip install *.tar.gz`` does the actual
+    installation. If ``*.whl`` is available, ``pip`` will go ahead and copy
+    the files into ``site-packages`` directory. If not, ``pip`` will look at
+    ``pyproject.toml`` and decide what program to use to 'build from source' 
+    (the default is ``setuptools``)
+
+With this standard, switching between packaging tools becomes a lot easier. ``build_meta``
+implements ``setuptools``' build system support.
+
+How to use it?
+--------------
+
+Starting with a package that you want to distribute. You will need your source
+scripts, a ``pyproject.toml`` file and a ``setup.cfg`` file::
+
+    ~/meowpkg/
+        pyproject.toml
+        setup.cfg
+        meowpkg/__init__.py
+
+The pyproject.toml file is required to specify the build system (i.e. what is 
+being used to package your scripts and install from source). To use it with 
+setuptools, the content would be::
+
+    [build-system]
+    requires = ["setuptools", "wheel"]
+    build-backend = "setuptools.build_meta" 
+
+Use ``setuptools``' `declarative config`_ to specify the package information::
+
+    [metadata]
+    name = meowpkg
+    version = 0.0.1
+    description = a package that meows
+    
+    [options]
+    packages = find:
+
+Now generate the distribution. Although the PyPA is still working to
+`provide a recommended tool <https://github.com/pypa/packaging-problems/issues/219>`_
+to build packages, the `pep517 package <https://pypi.org/project/pep517`_
+provides this functionality. To build the package::
+
+    $ pip install -q pep517
+    $ mkdir dist
+    $ python -m pep517.build .
+
+And now it's done! The ``.whl`` file  and ``.tar.gz`` can then be distributed 
+and installed::
+
+    dist/
+        meowpkg-0.0.1.whl
+        meowpkg-0.0.1.tar.gz
+
+    $ pip install dist/meowpkg-0.0.1.whl
+
+or::
+
+    $ pip install dist/meowpkg-0.0.1.tar.gz
diff --git a/docs/conf.py b/docs/conf.py
index c7eb6d3f..b92b50cc 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,23 +1,3 @@
-# -*- coding: utf-8 -*-
-#
-# Setuptools documentation build configuration file, created by
-# sphinx-quickstart on Fri Jul 17 14:22:37 2009.
-#
-# This file is execfile()d with the current directory set to its containing dir.
-#
-# The contents of this file are pickled, so don't put values in the namespace
-# that aren't pickleable (module imports are okay, they're removed automatically).
-#
-# Note that not all possible configuration values are present in this
-# autogenerated file.
-#
-# All configuration values have a default; values that are commented out
-# serve to show the default
-
-# If extensions (or modules to document with autodoc) are in another directory,
-# add these directories to sys.path here. If the directory is relative to the
-# documentation root, use os.path.abspath to make it absolute, like shown here.
-
 import subprocess
 import sys
 import os
@@ -26,14 +6,12 @@ import os
 # hack to run the bootstrap script so that jaraco.packaging.sphinx
 # can invoke setup.py
 'READTHEDOCS' in os.environ and subprocess.check_call(
-    [sys.executable, 'bootstrap.py'],
+    [sys.executable, '-m', 'bootstrap'],
     cwd=os.path.join(os.path.dirname(__file__), os.path.pardir),
 )
 
-# -- General configuration -----------------------------------------------------
+# -- General configuration --
 
-# Add any Sphinx extension module names here, as strings. They can be extensions
-# coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = ['jaraco.packaging.sphinx', 'rst.linker']
 
 # Add any paths that contain templates here, relative to this directory.
@@ -45,7 +23,8 @@ source_suffix = '.txt'
 # The master toctree document.
 master_doc = 'index'
 
-# A list of glob-style patterns that should be excluded when looking for source files.
+# A list of glob-style patterns that should be excluded
+# when looking for source files.
 exclude_patterns = ['requirements.txt']
 
 # List of directories, relative to source directory, that shouldn't be searched
@@ -55,7 +34,7 @@ exclude_trees = []
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'sphinx'
 
-# -- Options for HTML output ---------------------------------------------------
+# -- Options for HTML output --
 
 # The theme to use for HTML and HTML Help pages.  Major themes that come with
 # Sphinx are currently 'default' and 'sphinxdoc'.
@@ -69,7 +48,10 @@ html_theme_path = ['_theme']
 html_use_smartypants = True
 
 # Custom sidebar templates, maps document names to template names.
-html_sidebars = {'index': 'indexsidebar.html'}
+html_sidebars = {
+    'index': [
+        'relations.html', 'sourcelink.html', 'indexsidebar.html',
+        'searchbox.html']}
 
 # If false, no module index is generated.
 html_use_modindex = False
@@ -77,14 +59,15 @@ html_use_modindex = False
 # If false, no index is generated.
 html_use_index = False
 
-# -- Options for LaTeX output --------------------------------------------------
+# -- Options for LaTeX output --
 
 # Grouping the document tree into LaTeX files. List of tuples
-# (source start file, target name, title, author, documentclass [howto/manual]).
-latex_documents = [
-  ('index', 'Setuptools.tex', 'Setuptools Documentation',
-   'The fellowship of the packaging', 'manual'),
-]
+# (source start file, target name, title, author,
+# documentclass [howto/manual]).
+latex_documents = [(
+    'index', 'Setuptools.tex', 'Setuptools Documentation',
+    'The fellowship of the packaging', 'manual',
+)]
 
 link_files = {
     '../CHANGES.rst': dict(
diff --git a/docs/developer-guide.txt b/docs/developer-guide.txt
index d145fba1..e6171e4e 100644
--- a/docs/developer-guide.txt
+++ b/docs/developer-guide.txt
@@ -104,12 +104,8 @@ from the command line after pushing a new branch.
 Testing
 -------
 
-The primary tests are run using tox. To run the tests, first create the metadata
-needed to run the tests::
-
-    $ python bootstrap.py
-
-Then make sure you have tox installed, and invoke it::
+The primary tests are run using tox.  Make sure you have tox installed,
+and invoke it::
 
     $ tox
 
@@ -143,7 +139,7 @@ Vendored Dependencies
 ---------------------
 
 Setuptools has some dependencies, but due to `bootstrapping issues
-<https://github.com/pypa/setuptools/issues/980>`, those dependencies
+<https://github.com/pypa/setuptools/issues/980>`_, those dependencies
 cannot be declared as they won't be resolved soon enough to build
 setuptools from source. Eventually, this limitation may be lifted as
 PEP 517/518 reach ubiquitous adoption, but for now, Setuptools
diff --git a/docs/development.txt b/docs/development.txt
index 455f038a..28e653fe 100644
--- a/docs/development.txt
+++ b/docs/development.txt
@@ -7,7 +7,7 @@ Authority (PyPA) and led by Jason R. Coombs.
 
 This document describes the process by which Setuptools is developed.
 This document assumes the reader has some passing familiarity with
-*using* setuptools, the ``pkg_resources`` module, and EasyInstall.  It
+*using* setuptools, the ``pkg_resources`` module, and pip.  It
 does not attempt to explain basic concepts like inter-project
 dependencies, nor does it contain detailed lexical syntax for most
 file formats.  Neither does it explain concepts like "namespace
diff --git a/docs/easy_install.txt b/docs/easy_install.txt
index aa11f890..fac7b8fc 100644
--- a/docs/easy_install.txt
+++ b/docs/easy_install.txt
@@ -41,7 +41,7 @@ Please see the `setuptools PyPI page <https://pypi.org/project/setuptools/>`_
 for download links and basic installation instructions for each of the
 supported platforms.
 
-You will need at least Python 3.4 or 2.7.  An ``easy_install`` script will be
+You will need at least Python 3.5 or 2.7.  An ``easy_install`` script will be
 installed in the normal location for Python scripts on your platform.
 
 Note that the instructions on the setuptools PyPI page assume that you are
@@ -317,8 +317,8 @@ Note that instead of changing your ``PATH`` to include the Python scripts
 directory, you can also retarget the installation location for scripts so they
 go on a directory that's already on the ``PATH``.  For more information see
 `Command-Line Options`_ and `Configuration Files`_.  During installation,
-pass command line options (such as ``--script-dir``) to
-``ez_setup.py`` to control where ``easy_install.exe`` will be installed.
+pass command line options (such as ``--script-dir``) to control where
+scripts will be installed.
 
 
 Windows Executable Launcher
diff --git a/docs/ez_setup.txt b/docs/ez_setup.txt
deleted file mode 100644
index 0126fee3..00000000
--- a/docs/ez_setup.txt
+++ /dev/null
@@ -1,195 +0,0 @@
-:orphan:
-
-``ez_setup`` distribution guide 
-===============================
-
-Using ``setuptools``...  Without bundling it!
----------------------------------------------
-
-.. warning:: **ez_setup** is deprecated in favor of PIP with **PEP-518** support.
-
-.. _ez_setup.py: https://bootstrap.pypa.io/ez_setup.py
-
-.. _EasyInstall Installation Instructions: easy_install.html
-
-.. _Custom Installation Locations: easy_install.html
-
-Your users might not have ``setuptools`` installed on their machines, or even
-if they do, it might not be the right version.  Fixing this is easy; just
-download `ez_setup.py`_, and put it in the same directory as your ``setup.py``
-script.  (Be sure to add it to your revision control system, too.)  Then add
-these two lines to the very top of your setup script, before the script imports
-anything from setuptools:
-
-.. code-block:: python
-
-    import ez_setup
-    ez_setup.use_setuptools()
-
-That's it.  The ``ez_setup`` module will automatically download a matching
-version of ``setuptools`` from PyPI, if it isn't present on the target system.
-Whenever you install an updated version of setuptools, you should also update
-your projects' ``ez_setup.py`` files, so that a matching version gets installed
-on the target machine(s).
-
-(By the way, if you need to distribute a specific version of ``setuptools``,
-you can specify the exact version and base download URL as parameters to the
-``use_setuptools()`` function.  See the function's docstring for details.)
-
-
-What Your Users Should Know
----------------------------
-
-In general, a setuptools-based project looks just like any distutils-based
-project -- as long as your users have an internet connection and are installing
-to ``site-packages``, that is.  But for some users, these conditions don't
-apply, and they may become frustrated if this is their first encounter with
-a setuptools-based project.  To keep these users happy, you should review the
-following topics in your project's installation instructions, if they are
-relevant to your project and your target audience isn't already familiar with
-setuptools and ``easy_install``.
-
-Network Access
-    If your project is using ``ez_setup``, you should inform users of the
-    need to either have network access, or to preinstall the correct version of
-    setuptools using the `EasyInstall installation instructions`_.  Those
-    instructions also have tips for dealing with firewalls as well as how to
-    manually download and install setuptools.
-
-Custom Installation Locations
-    You should inform your users that if they are installing your project to
-    somewhere other than the main ``site-packages`` directory, they should
-    first install setuptools using the instructions for `Custom Installation
-    Locations`_, before installing your project.
-
-Your Project's Dependencies
-    If your project depends on other projects that may need to be downloaded
-    from PyPI or elsewhere, you should list them in your installation
-    instructions, or tell users how to find out what they are.  While most
-    users will not need this information, any users who don't have unrestricted
-    internet access may have to find, download, and install the other projects
-    manually.  (Note, however, that they must still install those projects
-    using ``easy_install``, or your project will not know they are installed,
-    and your setup script will try to download them again.)
-
-    If you want to be especially friendly to users with limited network access,
-    you may wish to build eggs for your project and its dependencies, making
-    them all available for download from your site, or at least create a page
-    with links to all of the needed eggs.  In this way, users with limited
-    network access can manually download all the eggs to a single directory,
-    then use the ``-f`` option of ``easy_install`` to specify the directory
-    to find eggs in.  Users who have full network access can just use ``-f``
-    with the URL of your download page, and ``easy_install`` will find all the
-    needed eggs using your links directly.  This is also useful when your
-    target audience isn't able to compile packages (e.g. most Windows users)
-    and your package or some of its dependencies include C code.
-
-Revision Control System Users and Co-Developers
-    Users and co-developers who are tracking your in-development code using
-    a revision control system should probably read this manual's sections
-    regarding such development.  Alternately, you may wish to create a
-    quick-reference guide containing the tips from this manual that apply to
-    your particular situation.  For example, if you recommend that people use
-    ``setup.py develop`` when tracking your in-development code, you should let
-    them know that this needs to be run after every update or commit.
-
-    Similarly, if you remove modules or data files from your project, you
-    should remind them to run ``setup.py clean --all`` and delete any obsolete
-    ``.pyc`` or ``.pyo``.  (This tip applies to the distutils in general, not
-    just setuptools, but not everybody knows about them; be kind to your users
-    by spelling out your project's best practices rather than leaving them
-    guessing.)
-
-Creating System Packages
-    Some users want to manage all Python packages using a single package
-    manager, and sometimes that package manager isn't ``easy_install``!
-    Setuptools currently supports ``bdist_rpm``, ``bdist_wininst``, and
-    ``bdist_dumb`` formats for system packaging.  If a user has a locally-
-    installed "bdist" packaging tool that internally uses the distutils
-    ``install`` command, it should be able to work with ``setuptools``.  Some
-    examples of "bdist" formats that this should work with include the
-    ``bdist_nsi`` and ``bdist_msi`` formats for Windows.
-
-    However, packaging tools that build binary distributions by running
-    ``setup.py install`` on the command line or as a subprocess will require
-    modification to work with setuptools.  They should use the
-    ``--single-version-externally-managed`` option to the ``install`` command,
-    combined with the standard ``--root`` or ``--record`` options.
-    See the `install command`_ documentation below for more details.  The
-    ``bdist_deb`` command is an example of a command that currently requires
-    this kind of patching to work with setuptools.
-
-    Please note that building system packages may require you to install
-    some system software, for example ``bdist_rpm`` requires the ``rpmbuild``
-    command to be installed.
-
-    If you or your users have a problem building a usable system package for
-    your project, please report the problem via the mailing list so that
-    either the "bdist" tool in question or setuptools can be modified to
-    resolve the issue.
-
-Your users might not have ``setuptools`` installed on their machines, or even
-if they do, it might not be the right version.  Fixing this is easy; just
-download `ez_setup.py`_, and put it in the same directory as your ``setup.py``
-script.  (Be sure to add it to your revision control system, too.)  Then add
-these two lines to the very top of your setup script, before the script imports
-anything from setuptools:
-
-.. code-block:: python
-
-    import ez_setup
-    ez_setup.use_setuptools()
-
-That's it.  The ``ez_setup`` module will automatically download a matching
-version of ``setuptools`` from PyPI, if it isn't present on the target system.
-Whenever you install an updated version of setuptools, you should also update
-your projects' ``ez_setup.py`` files, so that a matching version gets installed
-on the target machine(s).
-
-(By the way, if you need to distribute a specific version of ``setuptools``,
-you can specify the exact version and base download URL as parameters to the
-``use_setuptools()`` function.  See the function's docstring for details.)
-
-.. _install command:
-
-``install`` - Run ``easy_install`` or old-style installation
-============================================================
-
-The setuptools ``install`` command is basically a shortcut to run the
-``easy_install`` command on the current project.  However, for convenience
-in creating "system packages" of setuptools-based projects, you can also
-use this option:
-
-``--single-version-externally-managed``
-    This boolean option tells the ``install`` command to perform an "old style"
-    installation, with the addition of an ``.egg-info`` directory so that the
-    installed project will still have its metadata available and operate
-    normally.  If you use this option, you *must* also specify the ``--root``
-    or ``--record`` options (or both), because otherwise you will have no way
-    to identify and remove the installed files.
-
-This option is automatically in effect when ``install`` is invoked by another
-distutils command, so that commands like ``bdist_wininst`` and ``bdist_rpm``
-will create system packages of eggs.  It is also automatically in effect if
-you specify the ``--root`` option.
-
-
-``install_egg_info`` - Install an ``.egg-info`` directory in ``site-packages``
-==============================================================================
-
-Setuptools runs this command as part of ``install`` operations that use the
-``--single-version-externally-managed`` options.  You should not invoke it
-directly; it is documented here for completeness and so that distutils
-extensions such as system package builders can make use of it.  This command
-has only one option:
-
-``--install-dir=DIR, -d DIR``
-    The parent directory where the ``.egg-info`` directory will be placed.
-    Defaults to the same as the ``--install-dir`` option specified for the
-    ``install_lib`` command, which is usually the system ``site-packages``
-    directory.
-
-This command assumes that the ``egg_info`` command has been given valid options
-via the command line or ``setup.cfg``, as it will invoke the ``egg_info``
-command and use its options to locate the project's source ``.egg-info``
-directory.
diff --git a/docs/formats.txt b/docs/formats.txt
index a182eb99..6c0456de 100644
--- a/docs/formats.txt
+++ b/docs/formats.txt
@@ -299,11 +299,8 @@ specified by the ``setup_requires`` parameter to the Distribution.
 A list of dependency URLs, one per line, as specified using the
 ``dependency_links`` keyword to ``setup()``.  These may be direct
 download URLs, or the URLs of web pages containing direct download
-links, and will be used by EasyInstall to find dependencies, as though
-the user had manually provided them via the ``--find-links`` command
-line option.  Please see the setuptools manual and EasyInstall manual
-for more information on specifying this option, and for information on
-how EasyInstall processes ``--find-links`` URLs.
+links. Please see the setuptools manual for more information on
+specifying this option.
 
 
 ``depends.txt`` -- Obsolete, do not create!
diff --git a/docs/history.txt b/docs/history.txt
index 385cfa7e..faf7adfe 100644
--- a/docs/history.txt
+++ b/docs/history.txt
@@ -12,7 +12,7 @@ Credits
 
 * The original design for the ``.egg`` format and the ``pkg_resources`` API was
   co-created by Phillip Eby and Bob Ippolito. Bob also implemented the first
-  version of ``pkg_resources``, and supplied the OS X operating system version
+  version of ``pkg_resources``, and supplied the macOS operating system version
   compatibility algorithm.
 
 * Ian Bicking implemented many early "creature comfort" features of
diff --git a/docs/keywords.txt b/docs/keywords.txt
new file mode 100644
index 00000000..56356190
--- /dev/null
+++ b/docs/keywords.txt
@@ -0,0 +1,336 @@
+``name``
+    A string specifying the name of the package.
+
+``version``
+    A string specifying the version number of the package.
+
+``description``
+    A string describing the package in a single line.
+
+``long_description``
+    A string providing a longer description of the package.
+
+``long_description_content_type``
+    A string specifying the content type is used for the ``long_description``
+    (e.g. ``text/markdown``)
+
+``author``
+    A string specifying the author of the package.
+
+``author_email``
+    A string specifying the email address of the package author.
+
+``maintainer``
+    A string specifying the name of the current maintainer, if different from
+    the author. Note that if the maintainer is provided, setuptools will use it
+    as the author in ``PKG-INFO``.
+
+``maintainer_email``
+    A string specifying the email address of the current maintainer, if
+    different from the author.
+
+``url``
+    A string specifying the URL for the package homepage.
+
+``download_url``
+    A string specifying the URL to download the package.
+
+``packages``
+    A list of strings specifying the packages that setuptools will manipulate.
+
+``py_modules``
+    A list of strings specifying the modules that setuptools will manipulate.
+
+``scripts``
+    A list of strings specifying the standalone script files to be built and
+    installed.
+
+``ext_package``
+    A string specifying the base package name for the extensions provided by
+    this package.
+
+``ext_modules``
+    A list of instances of ``setuptools.Extension`` providing the list of
+    Python extensions to be built.
+
+``classifiers``
+    A list of strings describing the categories for the package.
+
+``distclass``
+    A subclass of ``Distribution`` to use.
+
+``script_name``
+    A string specifying the name of the setup.py script -- defaults to
+    ``sys.argv[0]``
+
+``script_args``
+    A list of strings defining the arguments to supply to the setup script.
+
+``options``
+    A dictionary providing the default options for the setup script.
+
+``license``
+    A string specifying the license of the package.
+
+``keywords``
+    A list of strings or a comma-separated string providing descriptive
+    meta-data. See: `PEP 0314`_.
+
+.. _PEP 0314: https://www.python.org/dev/peps/pep-0314/
+
+``platforms``
+    A list of strings or comma-separated string.
+
+``cmdclass``
+    A dictionary providing a mapping of command names to ``Command``
+    subclasses.
+
+``data_files``
+
+    .. warning::
+        ``data_files`` is deprecated. It does not work with wheels, so it
+        should be avoided.
+
+    A list of strings specifying the data files to install.
+
+``package_dir``
+    A dictionary providing a mapping of package to directory names.
+
+``requires``
+
+   .. warning::
+      ``requires`` is superseded by ``install_requires`` and should not be used
+      anymore.
+
+``obsoletes``
+
+   .. warning::
+      ``obsoletes`` is currently ignored by ``pip``.
+
+   List of strings describing packages which this package renders obsolete,
+   meaning that the two projects should not be installed at the same time.
+
+   Version declarations can be supplied. Version numbers must be in the format
+   specified in Version specifiers (e.g. ``foo (<3.0)``).
+
+   This field may be followed by an environment marker after a semicolon (e.g.
+   ``foo; os_name == "posix"``)
+
+   The most common use of this field will be in case a project name changes,
+   e.g. Gorgon 2.3 gets subsumed into Torqued Python 1.0. When you install
+   Torqued Python, the Gorgon distribution should be removed.
+
+``provides``
+
+   .. warning::
+      ``provides`` is currently ignored by ``pip``.
+
+   List of strings describing package- and virtual package names contained
+   within this package.
+
+   A package may provide additional names, e.g. to indicate that multiple
+   projects have been bundled together. For instance, source distributions of
+   the ZODB project have historically included the transaction project, which
+   is now available as a separate distribution. Installing such a source
+   distribution satisfies requirements for both ZODB and transaction.
+
+   A package may also provide a “virtual” project name, which does not
+   correspond to any separately-distributed project: such a name might be used
+   to indicate an abstract capability which could be supplied by one of
+   multiple projects. E.g., multiple projects might supply RDBMS bindings for
+   use by a given ORM: each project might declare that it provides
+   ORM-bindings, allowing other projects to depend only on having at most one
+   of them installed.
+
+   A version declaration may be supplied and must follow the rules described in
+   Version specifiers. The distribution’s version number will be implied if
+   none is specified (e.g. ``foo (<3.0)``).
+
+   Each package may be followed by an environment marker after a semicolon
+   (e.g. ``foo; os_name == "posix"``).
+
+.. Below are setuptools keywords, above are distutils
+
+``include_package_data``
+    If set to ``True``, this tells ``setuptools`` to automatically include any
+    data files it finds inside your package directories that are specified by
+    your ``MANIFEST.in`` file.  For more information, see the section on
+    :ref:`Including Data Files`.
+
+``exclude_package_data``
+    A dictionary mapping package names to lists of glob patterns that should
+    be *excluded* from your package directories.  You can use this to trim back
+    any excess files included by ``include_package_data``.  For a complete
+    description and examples, see the section on :ref:`Including Data Files`.
+
+``package_data``
+    A dictionary mapping package names to lists of glob patterns.  For a
+    complete description and examples, see the section on :ref:`Including Data
+    Files`.  You do not need to use this option if you are using
+    ``include_package_data``, unless you need to add e.g. files that are
+    generated by your setup script and build process.  (And are therefore not
+    in source control or are files that you don't want to include in your
+    source distribution.)
+
+``zip_safe``
+    A boolean (True or False) flag specifying whether the project can be
+    safely installed and run from a zip file.  If this argument is not
+    supplied, the ``bdist_egg`` command will have to analyze all of your
+    project's contents for possible problems each time it builds an egg.
+
+``install_requires``
+    A string or list of strings specifying what other distributions need to
+    be installed when this one is.  See the section on :ref:`Declaring
+    Dependencies` for details and examples of the format of this argument.
+
+``entry_points``
+    A dictionary mapping entry point group names to strings or lists of strings
+    defining the entry points.  Entry points are used to support dynamic
+    discovery of services or plugins provided by a project.  See :ref:`Dynamic
+    Discovery of Services and Plugins` for details and examples of the format
+    of this argument.  In addition, this keyword is used to support
+    :ref:`Automatic Script Creation`.
+
+``extras_require``
+    A dictionary mapping names of "extras" (optional features of your project)
+    to strings or lists of strings specifying what other distributions must be
+    installed to support those features.  See the section on :ref:`Declaring
+    Dependencies` for details and examples of the format of this argument.
+
+``python_requires``
+    A string corresponding to a version specifier (as defined in PEP 440) for
+    the Python version, used to specify the Requires-Python defined in PEP 345.
+
+``setup_requires``
+
+    .. warning::
+        Using ``setup_requires`` is discouraged in favor of `PEP-518`_
+
+    A string or list of strings specifying what other distributions need to
+    be present in order for the *setup script* to run.  ``setuptools`` will
+    attempt to obtain these (even going so far as to download them using
+    ``EasyInstall``) before processing the rest of the setup script or commands.
+    This argument is needed if you are using distutils extensions as part of
+    your build process; for example, extensions that process setup() arguments
+    and turn them into EGG-INFO metadata files.
+
+    (Note: projects listed in ``setup_requires`` will NOT be automatically
+    installed on the system where the setup script is being run.  They are
+    simply downloaded to the ./.eggs directory if they're not locally available
+    already.  If you want them to be installed, as well as being available
+    when the setup script is run, you should add them to ``install_requires``
+    **and** ``setup_requires``.)
+
+.. _PEP-518: http://www.python.org/dev/peps/pep-0518/
+
+``dependency_links``
+
+    .. warning::
+        ``dependency_links`` is deprecated. It is not supported anymore by pip.
+
+    A list of strings naming URLs to be searched when satisfying dependencies.
+    These links will be used if needed to install packages specified by
+    ``setup_requires`` or ``tests_require``.  They will also be written into
+    the egg's metadata for use by tools like EasyInstall to use when installing
+    an ``.egg`` file.
+
+``namespace_packages``
+    A list of strings naming the project's "namespace packages".  A namespace
+    package is a package that may be split across multiple project
+    distributions.  For example, Zope 3's ``zope`` package is a namespace
+    package, because subpackages like ``zope.interface`` and ``zope.publisher``
+    may be distributed separately.  The egg runtime system can automatically
+    merge such subpackages into a single parent package at runtime, as long
+    as you declare them in each project that contains any subpackages of the
+    namespace package, and as long as the namespace package's ``__init__.py``
+    does not contain any code other than a namespace declaration.  See the
+    section on :ref:`Namespace Packages` for more information.
+
+``test_suite``
+    A string naming a ``unittest.TestCase`` subclass (or a package or module
+    containing one or more of them, or a method of such a subclass), or naming
+    a function that can be called with no arguments and returns a
+    ``unittest.TestSuite``.  If the named suite is a module, and the module
+    has an ``additional_tests()`` function, it is called and the results are
+    added to the tests to be run.  If the named suite is a package, any
+    submodules and subpackages are recursively added to the overall test suite.
+
+    Specifying this argument enables use of the :ref:`test` command to run the
+    specified test suite, e.g. via ``setup.py test``.  See the section on the
+    :ref:`test` command below for more details.
+
+    New in 41.5.0: Deprecated the test command.
+
+``tests_require``
+    If your project's tests need one or more additional packages besides those
+    needed to install it, you can use this option to specify them.  It should
+    be a string or list of strings specifying what other distributions need to
+    be present for the package's tests to run.  When you run the ``test``
+    command, ``setuptools`` will  attempt to obtain these (even going
+    so far as to download them using ``EasyInstall``).  Note that these
+    required projects will *not* be installed on the system where the tests
+    are run, but only downloaded to the project's setup directory if they're
+    not already installed locally.
+
+    New in 41.5.0: Deprecated the test command.
+
+.. _test_loader:
+
+``test_loader``
+    If you would like to use a different way of finding tests to run than what
+    setuptools normally uses, you can specify a module name and class name in
+    this argument.  The named class must be instantiable with no arguments, and
+    its instances must support the ``loadTestsFromNames()`` method as defined
+    in the Python ``unittest`` module's ``TestLoader`` class.  Setuptools will
+    pass only one test "name" in the `names` argument: the value supplied for
+    the ``test_suite`` argument.  The loader you specify may interpret this
+    string in any way it likes, as there are no restrictions on what may be
+    contained in a ``test_suite`` string.
+
+    The module name and class name must be separated by a ``:``.  The default
+    value of this argument is ``"setuptools.command.test:ScanningLoader"``.  If
+    you want to use the default ``unittest`` behavior, you can specify
+    ``"unittest:TestLoader"`` as your ``test_loader`` argument instead.  This
+    will prevent automatic scanning of submodules and subpackages.
+
+    The module and class you specify here may be contained in another package,
+    as long as you use the ``tests_require`` option to ensure that the package
+    containing the loader class is available when the ``test`` command is run.
+
+    New in 41.5.0: Deprecated the test command.
+
+``eager_resources``
+    A list of strings naming resources that should be extracted together, if
+    any of them is needed, or if any C extensions included in the project are
+    imported.  This argument is only useful if the project will be installed as
+    a zipfile, and there is a need to have all of the listed resources be
+    extracted to the filesystem *as a unit*.  Resources listed here
+    should be '/'-separated paths, relative to the source root, so to list a
+    resource ``foo.png`` in package ``bar.baz``, you would include the string
+    ``bar/baz/foo.png`` in this argument.
+
+    If you only need to obtain resources one at a time, or you don't have any C
+    extensions that access other files in the project (such as data files or
+    shared libraries), you probably do NOT need this argument and shouldn't
+    mess with it.  For more details on how this argument works, see the section
+    below on :ref:`Automatic Resource Extraction`.
+
+``use_2to3``
+    Convert the source code from Python 2 to Python 3 with 2to3 during the
+    build process. See :doc:`python3` for more details.
+
+``convert_2to3_doctests``
+    List of doctest source files that need to be converted with 2to3.
+    See :doc:`python3` for more details.
+
+``use_2to3_fixers``
+    A list of modules to search for additional fixers to be used during
+    the 2to3 conversion. See :doc:`python3` for more details.
+
+``use_2to3_exclude_fixers``
+    List of fixer names to be skipped.
+
+``project_urls``
+    An arbitrary map of URL names to hyperlinks, allowing more extensible
+    documentation of where various resources can be found than the simple
+    ``url`` and ``download_url`` options provide.
diff --git a/docs/pkg_resources.txt b/docs/pkg_resources.txt
index 806f1b14..71568c1a 100644
--- a/docs/pkg_resources.txt
+++ b/docs/pkg_resources.txt
@@ -245,8 +245,8 @@ abbreviation for ``pkg_resources.working_set.require()``:
     interactive interpreter hacking than for production use. If you're creating
     an actual library or application, it's strongly recommended that you create
     a "setup.py" script using ``setuptools``, and declare all your requirements
-    there.  That way, tools like EasyInstall can automatically detect what
-    requirements your package has, and deal with them accordingly.
+    there.  That way, tools like pip can automatically detect what requirements
+    your package has, and deal with them accordingly.
 
     Note that calling ``require('SomePackage')`` will not install
     ``SomePackage`` if it isn't already present.  If you need to do this, you
@@ -611,9 +611,9 @@ Requirements Parsing
     or activation of both Report-O-Rama and any libraries it needs in order to
     provide PDF support.  For example, you could use::
 
-        easy_install.py Report-O-Rama[PDF]
+        pip install Report-O-Rama[PDF]
 
-    To install the necessary packages using the EasyInstall program, or call
+    To install the necessary packages using pip, or call
     ``pkg_resources.require('Report-O-Rama[PDF]')`` to add the necessary
     distributions to sys.path at runtime.
 
@@ -1621,7 +1621,7 @@ Platform Utilities
 
 ``get_build_platform()``
     Return this platform's identifier string.  For Windows, the return value
-    is ``"win32"``, and for Mac OS X it is a string of the form
+    is ``"win32"``, and for macOS it is a string of the form
     ``"macosx-10.4-ppc"``.  All other platforms return the same uname-based
     string that the ``distutils.util.get_platform()`` function returns.
     This string is the minimum platform version required by distributions built
@@ -1641,7 +1641,7 @@ Platform Utilities
     considered a wildcard, and the platforms are therefore compatible.
     Likewise, if the platform strings are equal, they're also considered
     compatible, and ``True`` is returned.  Currently, the only non-equal
-    platform strings that are considered compatible are Mac OS X platform
+    platform strings that are considered compatible are macOS platform
     strings with the same hardware type (e.g. ``ppc``) and major version
     (e.g. ``10``) with the `provided` platform's minor version being less than
     or equal to the `required` platform's minor version.
@@ -1674,7 +1674,7 @@ File/Path Utilities
     the same filesystem location if they have equal ``normalized_path()``
     values.  Specifically, this is a shortcut for calling ``os.path.realpath``
     and ``os.path.normcase`` on `path`.  Unfortunately, on certain platforms
-    (notably Cygwin and Mac OS X) the ``normcase`` function does not accurately
+    (notably Cygwin and macOS) the ``normcase`` function does not accurately
     reflect the platform's case-sensitivity, so there is always the possibility
     of two apparently-different paths being equal on such platforms.
 
@@ -1843,9 +1843,9 @@ History
      because it isn't necessarily a filesystem path (and hasn't been for some
      time now).  The ``location`` of ``Distribution`` objects in the filesystem
      should always be normalized using ``pkg_resources.normalize_path()``; all
-     of the setuptools and EasyInstall code that generates distributions from
-     the filesystem (including ``Distribution.from_filename()``) ensure this
-     invariant, but if you use a more generic API like ``Distribution()`` or
+     of the setuptools' code that generates distributions from the filesystem
+     (including ``Distribution.from_filename()``) ensure this invariant, but if
+     you use a more generic API like ``Distribution()`` or
      ``Distribution.from_location()`` you should take care that you don't
      create a distribution with an un-normalized filesystem path.
 
diff --git a/docs/releases.txt b/docs/releases.txt
index 98ba39e8..35b415c2 100644
--- a/docs/releases.txt
+++ b/docs/releases.txt
@@ -3,39 +3,13 @@ Release Process
 ===============
 
 In order to allow for rapid, predictable releases, Setuptools uses a
-mechanical technique for releases, enacted by Travis following a
-successful build of a tagged release per
-`PyPI deployment <https://docs.travis-ci.com/user/deployment/pypi>`_.
-
-Prior to cutting a release, please use `towncrier`_ to update
-``CHANGES.rst`` to summarize the changes since the last release.
-To update the changelog:
-
-1. Install towncrier via ``pip install towncrier`` if not already installed.
-2. Preview the new ``CHANGES.rst`` entry by running
-   ``towncrier --draft --version {new.version.number}`` (enter the desired
-   version number for the next release).  If any changes are needed, make
-   them and generate a new preview until the output is acceptable.  Run
-   ``git add`` for any modified files.
-3. Run ``towncrier --version {new.version.number}`` to stage the changelog
-   updates in git.
-4. Verify that there are no remaining ``changelog.d/*.rst`` files.  If a
-   file was named incorrectly, it may be ignored by towncrier.
-5. Review the updated ``CHANGES.rst`` file.  If any changes are needed,
-   make the edits and stage them via ``git add CHANGES.rst``.
-
-Once the changelog edits are staged and ready to commit, cut a release by
-installing and running ``bump2version --allow-dirty {part}`` where ``part``
-is major, minor, or patch based on the scope of the changes in the
-release. Then, push the commits to the master branch::
-
-    $ git push origin master
-    $ git push --tags
-
-If tests pass, the release will be uploaded to PyPI (from the Python 3.6
-tests).
-
-.. _towncrier: https://pypi.org/project/towncrier/
+mechanical technique for releases, enacted on tagged commits by
+continuous integration.
+
+To finalize a release, run ``tox -e finalize``, review, then push
+the changes.
+
+If tests pass, the release will be uploaded to PyPI.
 
 Release Frequency
 -----------------
diff --git a/docs/requirements.txt b/docs/requirements.txt
index bc27165b..104d68fa 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,5 +1,7 @@
-sphinx!=1.8.0
-rst.linker>=1.9
+# keep these in sync with setup.cfg
+sphinx
 jaraco.packaging>=6.1
+rst.linker>=1.9
+pygments-github-lexers==0.0.5
 
 setuptools>=34
diff --git a/docs/setuptools.txt b/docs/setuptools.txt
index 2e7fe3bd..7e0914b7 100644
--- a/docs/setuptools.txt
+++ b/docs/setuptools.txt
@@ -8,23 +8,10 @@ distribute Python packages, especially ones that have dependencies on other
 packages.
 
 Packages built and distributed using ``setuptools`` look to the user like
-ordinary Python packages based on the ``distutils``.  Your users don't need to
-install or even know about setuptools in order to use them, and you don't
-have to include the entire setuptools package in your distributions.  By
-including just a single `bootstrap module`_ (a 12K .py file), your package will
-automatically download and install ``setuptools`` if the user is building your
-package from source and doesn't have a suitable version already installed.
-
-.. _bootstrap module: https://bootstrap.pypa.io/ez_setup.py
+ordinary Python packages based on the ``distutils``.
 
 Feature Highlights:
 
-* Automatically find/download/install/upgrade dependencies at build time using
-  the `EasyInstall tool <easy_install.html>`_,
-  which supports downloading via HTTP, FTP, Subversion, and SourceForge, and
-  automatically scans web pages linked from PyPI to find download links.  (It's
-  the closest thing to CPAN currently available for Python.)
-
 * Create `Python Eggs <http://peak.telecommunity.com/DevCenter/PythonEggs>`_ -
   a single-file importable distribution format
 
@@ -62,8 +49,6 @@ Feature Highlights:
 
 .. contents:: **Table of Contents**
 
-.. _ez_setup.py: `bootstrap module`_
-
 
 -----------------
 Developer's Guide
@@ -73,15 +58,11 @@ Developer's Guide
 Installing ``setuptools``
 =========================
 
-.. _EasyInstall Installation Instructions: easy_install.html
-
-.. _Custom Installation Locations: easy_install.html
-
 .. _Installing Packages: https://packaging.python.org/tutorials/installing-packages/
 
 To install the latest version of setuptools, use::
 
-    pip install -U setuptools
+    pip install --upgrade setuptools
 
 Refer to `Installing Packages`_ guide for more information.
 
@@ -107,7 +88,7 @@ packages in the directory where the setup.py lives.  See the `Command
 Reference`_ section below to see what commands you can give to this setup
 script. For example, to produce a source distribution, simply invoke::
 
-    python setup.py sdist
+    setup.py sdist
 
 Of course, before you release your project to PyPI, you'll want to add a bit
 more information to your setup script to help people find or learn about your
@@ -119,17 +100,17 @@ dependencies, and perhaps some data files and scripts::
         name="HelloWorld",
         version="0.1",
         packages=find_packages(),
-        scripts=['say_hello.py'],
+        scripts=["say_hello.py"],
 
         # Project uses reStructuredText, so ensure that the docutils get
         # installed or upgraded on the target machine
-        install_requires=['docutils>=0.3'],
+        install_requires=["docutils>=0.3"],
 
         package_data={
             # If any package contains *.txt or *.rst files, include them:
-            '': ['*.txt', '*.rst'],
-            # And include any *.msg files found in the 'hello' package, too:
-            'hello': ['*.msg'],
+            "": ["*.txt", "*.rst"],
+            # And include any *.msg files found in the "hello" package, too:
+            "hello": ["*.msg"],
         },
 
         # metadata to display on PyPI
@@ -144,7 +125,7 @@ dependencies, and perhaps some data files and scripts::
             "Source Code": "https://code.example.com/HelloWorld/",
         },
         classifiers=[
-            'License :: OSI Approved :: Python Software Foundation License'
+            "License :: OSI Approved :: Python Software Foundation License"
         ]
 
         # could also include long_description, download_url, etc.
@@ -160,7 +141,7 @@ Specifying Your Project's Version
 
 Setuptools can work well with most versioning schemes; there are, however, a
 few special things to watch out for, in order to ensure that setuptools and
-EasyInstall can always tell what version of your package is newer than another
+other tools can always tell what version of your package is newer than another
 version.  Knowing these things will also help you correctly specify what
 versions of other projects your project depends on.
 
@@ -226,11 +207,11 @@ but here are a few tips that will keep you out of trouble in the corner cases:
   to compare different version numbers::
 
     >>> from pkg_resources import parse_version
-    >>> parse_version('1.9.a.dev') == parse_version('1.9a0dev')
+    >>> parse_version("1.9.a.dev") == parse_version("1.9a0dev")
     True
-    >>> parse_version('2.1-rc2') < parse_version('2.1')
+    >>> parse_version("2.1-rc2") < parse_version("2.1")
     True
-    >>> parse_version('0.6a9dev-r41475') < parse_version('0.6a9')
+    >>> parse_version("0.6a9dev-r41475") < parse_version("0.6a9")
     True
 
 Once you've decided on a version numbering scheme for your project, you can
@@ -248,170 +229,7 @@ The following keyword arguments to ``setup()`` are added or changed by
 ``setuptools``.  All of them are optional; you do not have to supply them
 unless you need the associated ``setuptools`` feature.
 
-``include_package_data``
-    If set to ``True``, this tells ``setuptools`` to automatically include any
-    data files it finds inside your package directories that are specified by
-    your ``MANIFEST.in`` file.  For more information, see the section below on
-    `Including Data Files`_.
-
-``exclude_package_data``
-    A dictionary mapping package names to lists of glob patterns that should
-    be *excluded* from your package directories.  You can use this to trim back
-    any excess files included by ``include_package_data``.  For a complete
-    description and examples, see the section below on `Including Data Files`_.
-
-``package_data``
-    A dictionary mapping package names to lists of glob patterns.  For a
-    complete description and examples, see the section below on `Including
-    Data Files`_.  You do not need to use this option if you are using
-    ``include_package_data``, unless you need to add e.g. files that are
-    generated by your setup script and build process.  (And are therefore not
-    in source control or are files that you don't want to include in your
-    source distribution.)
-
-``zip_safe``
-    A boolean (True or False) flag specifying whether the project can be
-    safely installed and run from a zip file.  If this argument is not
-    supplied, the ``bdist_egg`` command will have to analyze all of your
-    project's contents for possible problems each time it builds an egg.
-
-``install_requires``
-    A string or list of strings specifying what other distributions need to
-    be installed when this one is.  See the section below on `Declaring
-    Dependencies`_ for details and examples of the format of this argument.
-
-``entry_points``
-    A dictionary mapping entry point group names to strings or lists of strings
-    defining the entry points.  Entry points are used to support dynamic
-    discovery of services or plugins provided by a project.  See `Dynamic
-    Discovery of Services and Plugins`_ for details and examples of the format
-    of this argument.  In addition, this keyword is used to support `Automatic
-    Script Creation`_.
-
-``extras_require``
-    A dictionary mapping names of "extras" (optional features of your project)
-    to strings or lists of strings specifying what other distributions must be
-    installed to support those features.  See the section below on `Declaring
-    Dependencies`_ for details and examples of the format of this argument.
-
-``python_requires``
-    A string corresponding to a version specifier (as defined in PEP 440) for
-    the Python version, used to specify the Requires-Python defined in PEP 345.
-
-``setup_requires``
-    A string or list of strings specifying what other distributions need to
-    be present in order for the *setup script* to run.  ``setuptools`` will
-    attempt to obtain these (even going so far as to download them using
-    ``EasyInstall``) before processing the rest of the setup script or commands.
-    This argument is needed if you are using distutils extensions as part of
-    your build process; for example, extensions that process setup() arguments
-    and turn them into EGG-INFO metadata files.
-
-    (Note: projects listed in ``setup_requires`` will NOT be automatically
-    installed on the system where the setup script is being run.  They are
-    simply downloaded to the ./.eggs directory if they're not locally available
-    already.  If you want them to be installed, as well as being available
-    when the setup script is run, you should add them to ``install_requires``
-    **and** ``setup_requires``.)
-
-``dependency_links``
-    A list of strings naming URLs to be searched when satisfying dependencies.
-    These links will be used if needed to install packages specified by
-    ``setup_requires`` or ``tests_require``.  They will also be written into
-    the egg's metadata for use by tools like EasyInstall to use when installing
-    an ``.egg`` file.
-
-``namespace_packages``
-    A list of strings naming the project's "namespace packages".  A namespace
-    package is a package that may be split across multiple project
-    distributions.  For example, Zope 3's ``zope`` package is a namespace
-    package, because subpackages like ``zope.interface`` and ``zope.publisher``
-    may be distributed separately.  The egg runtime system can automatically
-    merge such subpackages into a single parent package at runtime, as long
-    as you declare them in each project that contains any subpackages of the
-    namespace package, and as long as the namespace package's ``__init__.py``
-    does not contain any code other than a namespace declaration.  See the
-    section below on `Namespace Packages`_ for more information.
-
-``test_suite``
-    A string naming a ``unittest.TestCase`` subclass (or a package or module
-    containing one or more of them, or a method of such a subclass), or naming
-    a function that can be called with no arguments and returns a
-    ``unittest.TestSuite``.  If the named suite is a module, and the module
-    has an ``additional_tests()`` function, it is called and the results are
-    added to the tests to be run.  If the named suite is a package, any
-    submodules and subpackages are recursively added to the overall test suite.
-
-    Specifying this argument enables use of the `test`_ command to run the
-    specified test suite, e.g. via ``setup.py test``.  See the section on the
-    `test`_ command below for more details.
-
-``tests_require``
-    If your project's tests need one or more additional packages besides those
-    needed to install it, you can use this option to specify them.  It should
-    be a string or list of strings specifying what other distributions need to
-    be present for the package's tests to run.  When you run the ``test``
-    command, ``setuptools`` will  attempt to obtain these (even going
-    so far as to download them using ``EasyInstall``).  Note that these
-    required projects will *not* be installed on the system where the tests
-    are run, but only downloaded to the project's setup directory if they're
-    not already installed locally.
-
-.. _test_loader:
-
-``test_loader``
-    If you would like to use a different way of finding tests to run than what
-    setuptools normally uses, you can specify a module name and class name in
-    this argument.  The named class must be instantiable with no arguments, and
-    its instances must support the ``loadTestsFromNames()`` method as defined
-    in the Python ``unittest`` module's ``TestLoader`` class.  Setuptools will
-    pass only one test "name" in the `names` argument: the value supplied for
-    the ``test_suite`` argument.  The loader you specify may interpret this
-    string in any way it likes, as there are no restrictions on what may be
-    contained in a ``test_suite`` string.
-
-    The module name and class name must be separated by a ``:``.  The default
-    value of this argument is ``"setuptools.command.test:ScanningLoader"``.  If
-    you want to use the default ``unittest`` behavior, you can specify
-    ``"unittest:TestLoader"`` as your ``test_loader`` argument instead.  This
-    will prevent automatic scanning of submodules and subpackages.
-
-    The module and class you specify here may be contained in another package,
-    as long as you use the ``tests_require`` option to ensure that the package
-    containing the loader class is available when the ``test`` command is run.
-
-``eager_resources``
-    A list of strings naming resources that should be extracted together, if
-    any of them is needed, or if any C extensions included in the project are
-    imported.  This argument is only useful if the project will be installed as
-    a zipfile, and there is a need to have all of the listed resources be
-    extracted to the filesystem *as a unit*.  Resources listed here
-    should be '/'-separated paths, relative to the source root, so to list a
-    resource ``foo.png`` in package ``bar.baz``, you would include the string
-    ``bar/baz/foo.png`` in this argument.
-
-    If you only need to obtain resources one at a time, or you don't have any C
-    extensions that access other files in the project (such as data files or
-    shared libraries), you probably do NOT need this argument and shouldn't
-    mess with it.  For more details on how this argument works, see the section
-    below on `Automatic Resource Extraction`_.
-
-``use_2to3``
-    Convert the source code from Python 2 to Python 3 with 2to3 during the
-    build process. See :doc:`python3` for more details.
-
-``convert_2to3_doctests``
-    List of doctest source files that need to be converted with 2to3.
-    See :doc:`python3` for more details.
-
-``use_2to3_fixers``
-    A list of modules to search for additional fixers to be used during
-    the 2to3 conversion. See :doc:`python3` for more details.
-
-``project_urls``
-    An arbitrary map of URL names to hyperlinks, allowing more extensible
-    documentation of where various resources can be found than the simple
-    ``url`` and ``download_url`` options provide.
+.. include:: keywords.txt
 
 
 Using ``find_packages()``
@@ -428,7 +246,7 @@ the same
 directory as the setup script.  Some projects use a ``src`` or ``lib``
 directory as the root of their source tree, and those projects would of course
 use ``"src"`` or ``"lib"`` as the first argument to ``find_packages()``.  (And
-such projects also need something like ``package_dir={'':'src'}`` in their
+such projects also need something like ``package_dir={"": "src"}`` in their
 ``setup()`` arguments, but that's just a normal distutils thing.)
 
 Anyway, ``find_packages()`` walks the target directory, filtering by inclusion
@@ -495,7 +313,7 @@ top-level package called ``tests``! One way to avoid this problem is to use the
     setup(
         name="namespace.mypackage",
         version="0.1",
-        packages=find_namespace_packages(include=['namespace.*'])
+        packages=find_namespace_packages(include=["namespace.*"])
     )
 
 Another option is to use the "src" layout, where all package code is placed in
@@ -515,11 +333,13 @@ With this layout, the package directory is specified as ``src``, as such::
 
     setup(name="namespace.mypackage",
           version="0.1",
-          package_dir={'': 'src'},
-          packages=find_namespace_packages(where='src'))
+          package_dir={"": "src"},
+          packages=find_namespace_packages(where="src"))
 
 .. _PEP 420: https://www.python.org/dev/peps/pep-0420/
 
+.. _Automatic Script Creation:
+
 Automatic Script Creation
 =========================
 
@@ -541,22 +361,23 @@ script called ``baz``, you might do something like this::
     setup(
         # other arguments here...
         entry_points={
-            'console_scripts': [
-                'foo = my_package.some_module:main_func',
-                'bar = other_module:some_func',
+            "console_scripts": [
+                "foo = my_package.some_module:main_func",
+                "bar = other_module:some_func",
             ],
-            'gui_scripts': [
-                'baz = my_package_gui:start_func',
+            "gui_scripts": [
+                "baz = my_package_gui:start_func",
             ]
         }
     )
 
 When this project is installed on non-Windows platforms (using "setup.py
-install", "setup.py develop", or by using EasyInstall), a set of ``foo``,
-``bar``, and ``baz`` scripts will be installed that import ``main_func`` and
-``some_func`` from the specified modules.  The functions you specify are called
-with no arguments, and their return value is passed to ``sys.exit()``, so you
-can return an errorlevel or message to print to stderr.
+install", "setup.py develop", or with pip), a set of ``foo``, ``bar``,
+and ``baz`` scripts will be installed that import ``main_func`` and
+``some_func`` from the specified modules.  The functions you specify are
+called with no arguments, and their return value is passed to
+``sys.exit()``, so you can return an errorlevel or message to print to
+stderr.
 
 On Windows, a set of ``foo.exe``, ``bar.exe``, and ``baz.exe`` launchers are
 created, alongside a set of ``foo.py``, ``bar.py``, and ``baz.pyw`` files.  The
@@ -574,6 +395,8 @@ Services and Plugins`_.
 "Eggsecutable" Scripts
 ----------------------
 
+.. deprecated:: 45.3.0
+
 Occasionally, there are situations where it's desirable to make an ``.egg``
 file directly executable.  You can do this by including an entry point such
 as the following::
@@ -581,8 +404,8 @@ as the following::
     setup(
         # other arguments here...
         entry_points={
-            'setuptools.installation': [
-                'eggsecutable = my_package.some_module:main_func',
+            "setuptools.installation": [
+                "eggsecutable = my_package.some_module:main_func",
             ]
         }
     )
@@ -596,10 +419,6 @@ Python must be available via the ``PATH`` environment variable, under its
 "long" name.  That is, if the egg is built for Python 2.3, there must be a
 ``python2.3`` executable present in a directory on ``PATH``.
 
-This feature is primarily intended to support ez_setup the installation of
-setuptools itself on non-Windows platforms, but may also be useful for other
-projects as well.
-
 IMPORTANT NOTE: Eggs with an "eggsecutable" header cannot be renamed, or
 invoked via symlinks.  They *must* be invoked using their original filename, in
 order to ensure that, once running, ``pkg_resources`` will know what project
@@ -607,13 +426,14 @@ and version is in use.  The header script will check this and exit with an
 error if the ``.egg`` file has been renamed or is invoked via a symlink that
 changes its base name.
 
+.. _Declaring Dependencies:
 
 Declaring Dependencies
 ======================
 
 ``setuptools`` supports automatically installing dependencies when a package is
 installed, and including information about dependencies in Python Eggs (so that
-package management tools like EasyInstall can use the information).
+package management tools like pip can use the information).
 
 ``setuptools`` and ``pkg_resources`` use a common syntax for specifying a
 project's required dependencies.  This syntax consists of a project's PyPI
@@ -652,10 +472,9 @@ requirement in a string, each requirement must begin on a new line.
 
 This has three effects:
 
-1. When your project is installed, either by using EasyInstall, ``setup.py
-   install``, or ``setup.py develop``, all of the dependencies not already
-   installed will be located (via PyPI), downloaded, built (if necessary),
-   and installed.
+1. When your project is installed, either by using pip, ``setup.py install``,
+   or ``setup.py develop``, all of the dependencies not already installed will
+   be located (via PyPI), downloaded, built (if necessary), and installed.
 
 2. Any scripts in your project will be installed with wrappers that verify
    the availability of the specified dependencies at runtime, and ensure that
@@ -675,6 +494,10 @@ using ``setup.py develop``.)
 Dependencies that aren't in PyPI
 --------------------------------
 
+.. warning::
+    Dependency links support has been dropped by pip starting with version
+    19.0 (released 2019-01-22).
+
 If your project depends on packages that don't exist on PyPI, you may still be
 able to depend on them, as long as they are available for download as:
 
@@ -725,9 +548,8 @@ This will do a checkout (or a clone, in Git and Mercurial parlance) to a
 temporary folder and run ``setup.py bdist_egg``.
 
 The ``dependency_links`` option takes the form of a list of URL strings.  For
-example, the below will cause EasyInstall to search the specified page for
-eggs or source distributions, if the package's dependencies aren't already
-installed::
+example, this will cause a search of the specified page for eggs or source
+distributions, if the package's dependencies aren't already installed::
 
     setup(
         ...
@@ -757,8 +579,8 @@ For example, let's say that Project A offers optional PDF and reST support::
         name="Project-A",
         ...
         extras_require={
-            'PDF':  ["ReportLab>=1.2", "RXP"],
-            'reST': ["docutils>=0.3"],
+            "PDF":  ["ReportLab>=1.2", "RXP"],
+            "reST": ["docutils>=0.3"],
         }
     )
 
@@ -767,7 +589,7 @@ names of "extra" features, to strings or lists of strings describing those
 features' requirements.  These requirements will *not* be automatically
 installed unless another package depends on them (directly or indirectly) by
 including the desired "extras" in square brackets after the associated project
-name.  (Or if the extras were listed in a requirement spec on the EasyInstall
+name.  (Or if the extras were listed in a requirement spec on the "pip install"
 command line.)
 
 Extras can be used by a project's `entry points`_ to specify dynamic
@@ -779,9 +601,9 @@ declare it like this, so that the "PDF" requirements are only resolved if the
         name="Project-A",
         ...
         entry_points={
-            'console_scripts': [
-                'rst2pdf = project_a.tools.pdfgen [PDF]',
-                'rst2html = project_a.tools.htmlgen',
+            "console_scripts": [
+                "rst2pdf = project_a.tools.pdfgen [PDF]",
+                "rst2html = project_a.tools.htmlgen",
                 # more script entry points ...
             ],
         }
@@ -817,8 +639,8 @@ setup to this::
         name="Project-A",
         ...
         extras_require={
-            'PDF':  [],
-            'reST': ["docutils>=0.3"],
+            "PDF":  [],
+            "reST": ["docutils>=0.3"],
         }
     )
 
@@ -845,8 +667,8 @@ For example, here is a project that uses the ``enum`` module and ``pywin32``::
         name="Project",
         ...
         install_requires=[
-            'enum34;python_version<"3.4"',
-            'pywin32 >= 1.0;platform_system=="Windows"'
+            "enum34;python_version<'3.4'",
+            "pywin32 >= 1.0;platform_system=='Windows'"
         ]
     )
 
@@ -860,6 +682,8 @@ detailed in `PEP 508`_.
 
 .. _PEP 508: https://www.python.org/dev/peps/pep-0508/
 
+.. _Including Data Files:
+
 Including Data Files
 ====================
 
@@ -894,9 +718,9 @@ e.g.::
         ...
         package_data={
             # If any package contains *.txt or *.rst files, include them:
-            '': ['*.txt', '*.rst'],
-            # And include any *.msg files found in the 'hello' package, too:
-            'hello': ['*.msg'],
+            "": ["*.txt", "*.rst"],
+            # And include any *.msg files found in the "hello" package, too:
+            "hello": ["*.msg"],
         }
     )
 
@@ -919,15 +743,15 @@ The setuptools setup file might look like this::
     from setuptools import setup, find_packages
     setup(
         ...
-        packages=find_packages('src'),  # include all packages under src
-        package_dir={'':'src'},   # tell distutils packages are under src
+        packages=find_packages("src"),  # include all packages under src
+        package_dir={"": "src"},   # tell distutils packages are under src
 
         package_data={
             # If any package contains *.txt files, include them:
-            '': ['*.txt'],
-            # And include any *.dat files found in the 'data' subdirectory
-            # of the 'mypkg' package, also:
-            'mypkg': ['data/*.dat'],
+            "": ["*.txt"],
+            # And include any *.dat files found in the "data" subdirectory
+            # of the "mypkg" package, also:
+            "mypkg": ["data/*.dat"],
         }
     )
 
@@ -942,7 +766,7 @@ converts slashes to appropriate platform-specific separators at build time.
 
 If datafiles are contained in a subdirectory of a package that isn't a package
 itself (no ``__init__.py``), then the subdirectory names (or ``*``) are required
-in the ``package_data`` argument (as shown above with ``'data/*.dat'``).
+in the ``package_data`` argument (as shown above with ``"data/*.dat"``).
 
 When building an ``sdist``, the datafiles are also drawn from the
 ``package_name.egg-info/SOURCES.txt`` file, so make sure that this is removed if
@@ -955,7 +779,7 @@ python.org website.  If using the setuptools-specific ``include_package_data``
 argument, files specified by ``package_data`` will *not* be automatically
 added to the manifest unless they are listed in the MANIFEST.in file.)
 
-__ http://docs.python.org/dist/node11.html
+__ https://docs.python.org/3/distutils/setupscript.html#installing-package-data
 
 Sometimes, the ``include_package_data`` or ``package_data`` options alone
 aren't sufficient to precisely define what files you want included.  For
@@ -967,18 +791,18 @@ to do things like this::
     from setuptools import setup, find_packages
     setup(
         ...
-        packages=find_packages('src'),  # include all packages under src
-        package_dir={'':'src'},   # tell distutils packages are under src
+        packages=find_packages("src"),  # include all packages under src
+        package_dir={"": "src"},   # tell distutils packages are under src
 
         include_package_data=True,    # include everything in source control
 
         # ...but exclude README.txt from all packages
-        exclude_package_data={'': ['README.txt']},
+        exclude_package_data={"": ["README.txt"]},
     )
 
 The ``exclude_package_data`` option is a dictionary mapping package names to
 lists of wildcard patterns, just like the ``package_data`` option.  And, just
-as with that option, a key of ``''`` will apply the given pattern(s) to all
+as with that option, a key of ``""`` will apply the given pattern(s) to all
 packages.  However, any files that match these patterns will be *excluded*
 from installation, even if they were listed in ``package_data`` or were
 included as a result of using ``include_package_data``.
@@ -1016,11 +840,11 @@ and Python Eggs.  It is strongly recommended that, if you are using data files,
 you should use the :ref:`ResourceManager API` of ``pkg_resources`` to access
 them.  The ``pkg_resources`` module is distributed as part of setuptools, so if
 you're using setuptools to distribute your package, there is no reason not to
-use its resource management API.  See also `Accessing Package Resources`_ for
+use its resource management API.  See also `Importlib Resources`_ for
 a quick example of converting code that uses ``__file__`` to use
 ``pkg_resources`` instead.
 
-.. _Accessing Package Resources: http://peak.telecommunity.com/DevCenter/PythonEggs#accessing-package-resources
+.. _Importlib Resources: https://docs.python.org/3/library/importlib.html#module-importlib.resources
 
 
 Non-Package Data Files
@@ -1035,6 +859,7 @@ no supported facility to reliably retrieve these resources.
 Instead, the PyPA recommends that any data files you wish to be accessible at
 run time be included in the package.
 
+.. _Automatic Resource Extraction:
 
 Automatic Resource Extraction
 -----------------------------
@@ -1080,6 +905,8 @@ Extensible Applications and Frameworks
 
 .. _Entry Points:
 
+.. _Dynamic Discovery of Services and Plugins:
+
 Dynamic Discovery of Services and Plugins
 -----------------------------------------
 
@@ -1112,12 +939,12 @@ for our hypothetical blogging tool::
 
     setup(
         # ...
-        entry_points={'blogtool.parsers': '.rst = some_module:SomeClass'}
+        entry_points={"blogtool.parsers": ".rst = some_module:SomeClass"}
     )
 
     setup(
         # ...
-        entry_points={'blogtool.parsers': ['.rst = some_module:a_func']}
+        entry_points={"blogtool.parsers": [".rst = some_module:a_func"]}
     )
 
     setup(
@@ -1182,13 +1009,12 @@ preferred way of working (as opposed to using a common independent staging area
 or the site-packages directory).
 
 To do this, use the ``setup.py develop`` command.  It works very similarly to
-``setup.py install`` or the EasyInstall tool, except that it doesn't actually
-install anything.  Instead, it creates a special ``.egg-link`` file in the
-deployment directory, that links to your project's source code.  And, if your
-deployment directory is Python's ``site-packages`` directory, it will also
-update the ``easy-install.pth`` file to include your project's source code,
-thereby making it available on ``sys.path`` for all programs using that Python
-installation.
+``setup.py install``, except that it doesn't actually install anything.
+Instead, it creates a special ``.egg-link`` file in the deployment directory,
+that links to your project's source code.  And, if your deployment directory is
+Python's ``site-packages`` directory, it will also update the
+``easy-install.pth`` file to include your project's source code, thereby making
+it available on ``sys.path`` for all programs using that Python installation.
 
 If you have enabled the ``use_2to3`` flag, then of course the ``.egg-link``
 will not link directly to your source code when run under Python 3, since
@@ -1216,7 +1042,7 @@ command; see the section on the `develop`_ command below for more details.
 Note that you can also apply setuptools commands to non-setuptools projects,
 using commands like this::
 
-   python -c "import setuptools; execfile('setup.py')" develop
+   python -c "import setuptools; with open('setup.py') as f: exec(compile(f.read(), 'setup.py', 'exec'))" develop
 
 That is, you can simply list the normal setup commands and options following
 the quoted part.
@@ -1225,28 +1051,28 @@ the quoted part.
 Distributing a ``setuptools``-based project
 ===========================================
 
-Detailed instructions to distribute a setuptools project can be found at 
+Detailed instructions to distribute a setuptools project can be found at
 `Packaging project tutorials`_.
 
 .. _Packaging project tutorials: https://packaging.python.org/tutorials/packaging-projects/#generating-distribution-archives
 
 Before you begin, make sure you have the latest versions of setuptools and wheel::
 
-    python3 -m pip install --user --upgrade setuptools wheel
+    pip install --upgrade setuptools wheel
 
 To build a setuptools project, run this command from the same directory where
 setup.py is located::
 
-    python3 setup.py sdist bdist_wheel
+    setup.py sdist bdist_wheel
 
 This will generate distribution archives in the `dist` directory.
 
-Before you upload the generated archives make sure you're registered on 
+Before you upload the generated archives make sure you're registered on
 https://test.pypi.org/account/register/. You will also need to verify your email
 to be able to upload any packages.
 You should install twine to be able to upload packages::
 
-    python3 -m pip install --user --upgrade setuptools wheel
+    pip install --upgrade twine
 
 Now, to upload these archives, run::
 
@@ -1254,25 +1080,11 @@ Now, to upload these archives, run::
 
 To install your newly uploaded package ``example_pkg``,  you can use pip::
 
-    python3 -m pip install --index-url https://test.pypi.org/simple/ example_pkg
+    pip install --index-url https://test.pypi.org/simple/ example_pkg
 
 If you have issues at any point, please refer to `Packaging project tutorials`_
 for clarification.
 
-Distributing legacy ``setuptools`` projects using ez_setup.py
--------------------------------------------------------------
-
-.. warning:: **ez_setup** is deprecated in favor of PIP with **PEP-518** support.
-
-Distributing packages using the legacy ``ez_setup.py`` and ``easy_install`` is 
-deprecated in favor of PIP. Please consider migrating to using pip and twine based
-distribution.
-
-However, if you still have any ``ez_setup`` based packages, documentation for 
-ez_setup based distributions can be found at `ez_setup distribution guide`_.
-
-.. _ez_setup distribution guide: ez_setup.html
-
 Setting the ``zip_safe`` flag
 -----------------------------
 
@@ -1308,20 +1120,14 @@ you've checked over all the warnings it issued, and you are either satisfied it
 doesn't work, you can always change it to ``False``, which will force
 ``setuptools`` to install your project as a directory rather than as a zipfile.
 
-Of course, the end-user can still override either decision, if they are using
-EasyInstall to install your package.  And, if you want to override for testing
-purposes, you can just run ``setup.py easy_install --zip-ok .`` or ``setup.py
-easy_install --always-unzip .`` in your project directory. to install the
-package as a zipfile or directory, respectively.
-
 In the future, as we gain more experience with different packages and become
 more satisfied with the robustness of the ``pkg_resources`` runtime, the
 "zip safety" analysis may become less conservative.  However, we strongly
 recommend that you determine for yourself whether your project functions
 correctly when installed as a zipfile, correct any problems if you can, and
 then make an explicit declaration of ``True`` or ``False`` for the ``zip_safe``
-flag, so that it will not be necessary for ``bdist_egg`` or ``EasyInstall`` to
-try to guess whether your project can work as a zipfile.
+flag, so that it will not be necessary for ``bdist_egg`` to try to guess
+whether your project can work as a zipfile.
 
 .. _Namespace Packages:
 
@@ -1346,7 +1152,7 @@ participates in.  For example, the ZopeInterface project might do this::
 
     setup(
         # ...
-        namespace_packages=['zope']
+        namespace_packages=["zope"]
     )
 
 because it contains a ``zope.interface`` package that lives in the ``zope``
@@ -1364,7 +1170,7 @@ packages' ``__init__.py`` files (and the ``__init__.py`` of any parent
 packages), in a normal Python package layout.  These ``__init__.py`` files
 *must* contain the line::
 
-    __import__('pkg_resources').declare_namespace(__name__)
+    __import__("pkg_resources").declare_namespace(__name__)
 
 This code ensures that the namespace package machinery is operating and that
 the current package is registered as a namespace package.
@@ -1435,9 +1241,9 @@ to generate a daily build or snapshot for.  See the section below on the
 
 (Also, before you release your project, be sure to see the section above on
 `Specifying Your Project's Version`_ for more information about how pre- and
-post-release tags affect how setuptools and EasyInstall interpret version
-numbers.  This is important in order to make sure that dependency processing
-tools will know which versions of your project are newer than others.)
+post-release tags affect how version numbers are interpreted.  This is
+important in order to make sure that dependency processing tools will know
+which versions of your project are newer than others.)
 
 Finally, if you are creating builds frequently, and either building them in a
 downloadable location or are copying them to a distribution server, you should
@@ -1447,7 +1253,7 @@ pattern.  So, you can use a command line like::
 
     setup.py egg_info -rbDEV bdist_egg rotate -m.egg -k3
 
-to build an egg whose version info includes 'DEV-rNNNN' (where NNNN is the
+to build an egg whose version info includes "DEV-rNNNN" (where NNNN is the
 most recent Subversion revision that affected the source tree), and then
 delete any egg files from the distribution directory except for the three
 that were built most recently.
@@ -1493,58 +1299,6 @@ all practical purposes, you'll probably use only the ``--formats`` option, if
 you use any option at all.
 
 
-Making your package available for EasyInstall
----------------------------------------------
-
-There may be reasons why you don't want to upload distributions to
-PyPI, and just want your existing distributions (or perhaps a Subversion
-checkout) to be used instead.
-
-There are three ``setup()`` arguments that affect EasyInstall:
-
-``url`` and ``download_url``
-   These become links on your project's PyPI page.  EasyInstall will examine
-   them to see if they link to a package ("primary links"), or whether they are
-   HTML pages.  If they're HTML pages, EasyInstall scans all HREF's on the
-   page for primary links
-
-``long_description``
-   EasyInstall will check any URLs contained in this argument to see if they
-   are primary links.
-
-A URL is considered a "primary link" if it is a link to a .tar.gz, .tgz, .zip,
-.egg, .egg.zip, .tar.bz2, or .exe file, or if it has an ``#egg=project`` or
-``#egg=project-version`` fragment identifier attached to it.  EasyInstall
-attempts to determine a project name and optional version number from the text
-of a primary link *without* downloading it.  When it has found all the primary
-links, EasyInstall will select the best match based on requested version,
-platform compatibility, and other criteria.
-
-So, if your ``url`` or ``download_url`` point either directly to a downloadable
-source distribution, or to HTML page(s) that have direct links to such, then
-EasyInstall will be able to locate downloads automatically.  If you want to
-make Subversion checkouts available, then you should create links with either
-``#egg=project`` or ``#egg=project-version`` added to the URL.  You should
-replace ``project`` and ``version`` with the values they would have in an egg
-filename.  (Be sure to actually generate an egg and then use the initial part
-of the filename, rather than trying to guess what the escaped form of the
-project name and version number will be.)
-
-Note that Subversion checkout links are of lower precedence than other kinds
-of distributions, so EasyInstall will not select a Subversion checkout for
-downloading unless it has a version included in the ``#egg=`` suffix, and
-it's a higher version than EasyInstall has seen in any other links for your
-project.
-
-As a result, it's a common practice to use mark checkout URLs with a version of
-"dev" (i.e., ``#egg=projectname-dev``), so that users can do something like
-this::
-
-    easy_install --editable projectname==dev
-
-in order to check out the in-development version of ``projectname``.
-
-
 Making "Official" (Non-Snapshot) Releases
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -1558,7 +1312,7 @@ tagging the release, so the trunk will still produce development snapshots.
 Alternately, if you are not branching for releases, you can override the
 default version options on the command line, using something like::
 
-    python setup.py egg_info -Db "" sdist bdist_egg
+    setup.py egg_info -Db "" sdist bdist_egg
 
 The first part of this command (``egg_info -Db ""``) will override the
 configured tag information, before creating source and binary eggs. Thus, these
@@ -1568,11 +1322,11 @@ build designation string.
 Of course, if you will be doing this a lot, you may wish to create a personal
 alias for this operation, e.g.::
 
-    python setup.py alias -u release egg_info -Db ""
+    setup.py alias -u release egg_info -Db ""
 
 You can then use it like this::
 
-    python setup.py release sdist bdist_egg
+    setup.py release sdist bdist_egg
 
 Or of course you can create more elaborate aliases that do all of the above.
 See the sections below on the `egg_info`_ and `alias`_ commands for more ideas.
@@ -1589,7 +1343,7 @@ To ensure Cython is available, include Cython in the build-requires section
 of your pyproject.toml::
 
     [build-system]
-    requires=[..., 'cython']
+    requires=[..., "cython"]
 
 Built with pip 10 or later, that declaration is sufficient to include Cython
 in the build. For broader compatibility, declare the dependency in your
@@ -1689,6 +1443,9 @@ file locations.
 ``bdist_egg`` - Create a Python Egg for the project
 ===================================================
 
+.. warning::
+    **eggs** are deprecated in favor of wheels, and not supported by pip.
+
 This command generates a Python Egg (``.egg`` file) for the project.  Python
 Eggs are the preferred binary distribution format for EasyInstall, because they
 are cross-platform (for "pure" packages), directly importable, and contain
@@ -1796,9 +1553,9 @@ Here are some of the options that the ``develop`` command accepts.  Note that
 they affect the project's dependencies as well as the project itself, so if you
 have dependencies that need to be installed and you use ``--exclude-scripts``
 (for example), the dependencies' scripts will not be installed either!  For
-this reason, you may want to use EasyInstall to install the project's
-dependencies before using the ``develop`` command, if you need finer control
-over the installation options for dependencies.
+this reason, you may want to use pip to install the project's dependencies
+before using the ``develop`` command, if you need finer control over the
+installation options for dependencies.
 
 ``--uninstall, -u``
     Un-deploy the current project.  You may use the ``--install-dir`` or ``-d``
@@ -1808,10 +1565,10 @@ over the installation options for dependencies.
     staging area is Python's ``site-packages`` directory.
 
     Note that this option currently does *not* uninstall script wrappers!  You
-    must uninstall them yourself, or overwrite them by using EasyInstall to
-    activate a different version of the package.  You can also avoid installing
-    script wrappers in the first place, if you use the ``--exclude-scripts``
-    (aka ``-x``) option when you run ``develop`` to deploy the project.
+    must uninstall them yourself, or overwrite them by using pip to install a
+    different version of the package.  You can also avoid installing script
+    wrappers in the first place, if you use the ``--exclude-scripts`` (aka
+    ``-x``) option when you run ``develop`` to deploy the project.
 
 ``--multi-version, -m``
     "Multi-version" mode. Specifying this option prevents ``develop`` from
@@ -1820,8 +1577,8 @@ over the installation options for dependencies.
     removed upon successful deployment.  In multi-version mode, no specific
     version of the package is available for importing, unless you use
     ``pkg_resources.require()`` to put it on ``sys.path``, or you are running
-    a wrapper script generated by ``setuptools`` or EasyInstall.  (In which
-    case the wrapper script calls ``require()`` for you.)
+    a wrapper script generated by ``setuptools``.  (In which case the wrapper
+    script calls ``require()`` for you.)
 
     Note that if you install to a directory other than ``site-packages``,
     this option is automatically in effect, because ``.pth`` files can only be
@@ -1874,25 +1631,6 @@ files), the ``develop`` command will use them as defaults, unless you override
 them in a ``[develop]`` section or on the command line.
 
 
-``easy_install`` - Find and install packages
-============================================
-
-This command runs the `EasyInstall tool
-<easy_install.html>`_ for you.  It is exactly
-equivalent to running the ``easy_install`` command.  All command line arguments
-following this command are consumed and not processed further by the distutils,
-so this must be the last command listed on the command line.  Please see
-the EasyInstall documentation for the options reference and usage examples.
-Normally, there is no reason to use this command via the command line, as you
-can just use ``easy_install`` directly.  It's only listed here so that you know
-it's a distutils command, which means that you can:
-
-* create command aliases that use it,
-* create distutils extensions that invoke it as a subcommand, and
-* configure options for it in your ``setup.cfg`` or other distutils config
-  files.
-
-
 .. _egg_info:
 
 ``egg_info`` - Create egg metadata and set build tags
@@ -1905,7 +1643,7 @@ to support "daily builds" or "snapshot" releases.  It is run automatically by
 the ``sdist``, ``bdist_egg``, ``develop``, and ``test`` commands in order to
 update the project's metadata, but you can also specify it explicitly in order
 to temporarily change the project's version string while executing other
-commands.  (It also generates the``.egg-info/SOURCES.txt`` manifest file, which
+commands.  (It also generates the ``.egg-info/SOURCES.txt`` manifest file, which
 is used when you are building source distributions.)
 
 In addition to writing the core egg metadata defined by ``setuptools`` and
@@ -1951,9 +1689,9 @@ added in the following order:
 (Note: Because these options modify the version number used for source and
 binary distributions of your project, you should first make sure that you know
 how the resulting version numbers will be interpreted by automated tools
-like EasyInstall.  See the section above on `Specifying Your Project's
-Version`_ for an explanation of pre- and post-release tags, as well as tips on
-how to choose and verify a versioning scheme for your your project.)
+like pip.  See the section above on `Specifying Your Project's Version`_ for an
+explanation of pre- and post-release tags, as well as tips on how to choose and
+verify a versioning scheme for your project.)
 
 For advanced uses, there is one other option that can be set, to change the
 location of the project's ``.egg-info`` directory.  Commands that need to find
@@ -1978,12 +1716,12 @@ Other ``egg_info`` Options
 
 Creating a dated "nightly build" snapshot egg::
 
-    python setup.py egg_info --tag-date --tag-build=DEV bdist_egg
+    setup.py egg_info --tag-date --tag-build=DEV bdist_egg
 
 Creating a release with no version tags, even if some default tags are
 specified in ``setup.cfg``::
 
-    python setup.py egg_info -RDb "" sdist bdist_egg
+    setup.py egg_info -RDb "" sdist bdist_egg
 
 (Notice that ``egg_info`` must always appear on the command line *before* any
 commands that you want the version changes to apply to.)
@@ -2135,6 +1873,11 @@ distutils configuration file the option will be added to (or removed from).
 ``test`` - Build package and run a unittest suite
 =================================================
 
+.. warning::
+    ``test`` is deprecated and will be removed in a future version. Users
+    looking for a generic test entry point independent of test runner are
+    encouraged to use `tox <https://tox.readthedocs.io>`_.
+
 When doing test-driven development, or running automated builds that need
 testing before they are deployed for downloading or use, it's often useful
 to be able to run a project's unit tests without actually deploying the project
@@ -2152,7 +1895,7 @@ result (which must be a ``unittest.TestSuite``) is added to the tests to be
 run.  If the named suite is a package, any submodules and subpackages are
 recursively added to the overall test suite.  (Note: if your project specifies
 a ``test_loader``, the rules for processing the chosen ``test_suite`` may
-differ; see the `test_loader`_ documentation for more details.)
+differ; see the :ref:`test_loader <test_loader>` documentation for more details.)
 
 Note that many test systems including ``doctest`` support wrapping their
 non-``unittest`` tests in ``TestSuite`` objects.  So, if you are using a test
@@ -2180,22 +1923,21 @@ available:
     If you did not set a ``test_suite`` in your ``setup()`` call, and do not
     provide a ``--test-suite`` option, an error will occur.
 
+New in 41.5.0: Deprecated the test command.
+
 
 .. _upload:
 
 ``upload`` - Upload source and/or egg distributions to PyPI
 ===========================================================
 
-.. warning::
-    **upload** is deprecated in favor of using `twine
-    <https://pypi.org/p/twine>`_
-
-The ``upload`` command is implemented and `documented
-<https://docs.python.org/3.1/distutils/uploading.html>`_
-in distutils.
+The ``upload`` command was deprecated in version 40.0 and removed in version
+42.0. Use `twine <https://pypi.org/p/twine>`_ instead.
 
-New in 20.1: Added keyring support.
-New in 40.0: Deprecated the upload command.
+For  more information on the current best practices in uploading your packages
+to PyPI, see the Python Packaging User Guide's "Packaging Python Projects"
+tutorial specifically the section on `uploading the distribution archives
+<https://packaging.python.org/tutorials/packaging-projects/#uploading-the-distribution-archives>`_.
 
 
 -----------------------------------------
@@ -2205,8 +1947,9 @@ Configuring setup() using setup.cfg files
 .. note:: New in 30.3.0 (8 Dec 2016).
 
 .. important::
-    A ``setup.py`` file containing a ``setup()`` function call is still
-    required even if your configuration resides in ``setup.cfg``.
+    If compatibility with legacy builds (i.e. those not using the :pep:`517`
+    build API) is desired, a ``setup.py`` file containing a ``setup()`` function
+    call is still required even if your configuration resides in ``setup.cfg``.
 
 ``Setuptools`` allows using configuration files (usually :file:`setup.cfg`)
 to define a package’s metadata and other options that are normally supplied
@@ -2291,11 +2034,54 @@ Metadata and options are set in the config sections of the same name.
 * In some cases, complex values can be provided in dedicated subsections for
   clarity.
 
-* Some keys allow ``file:``, ``attr:``, and ``find:`` and ``find_namespace:`` directives in
+* Some keys allow ``file:``, ``attr:``, ``find:``, and ``find_namespace:`` directives in
   order to cover common usecases.
 
 * Unknown keys are ignored.
 
+setup.cfg-only projects
+=======================
+
+.. versionadded:: 40.9.0
+
+If ``setup.py`` is missing from the project directory when a :pep:`517`
+build is invoked, ``setuptools`` emulates a dummy ``setup.py`` file containing
+only a ``setuptools.setup()`` call.
+
+.. note::
+
+    :pep:`517` doesn't support editable installs so this is currently
+    incompatible with ``pip install -e .``, as :pep:`517` does not support editable installs.
+
+This means that you can have a Python project with all build configuration
+specified in ``setup.cfg``, without a ``setup.py`` file, if you **can rely
+on** your project always being built by a :pep:`517`/:pep:`518` compatible
+frontend.
+
+To use this feature:
+
+* Specify build requirements and :pep:`517` build backend in
+  ``pyproject.toml``.
+  For example:
+
+  .. code-block:: toml
+
+      [build-system]
+      requires = [
+        "setuptools >= 40.9.0",
+        "wheel",
+      ]
+      build-backend = "setuptools.build_meta"
+
+* Use a :pep:`517` compatible build frontend, such as ``pip >= 19`` or ``pep517``.
+
+  .. warning::
+
+      As :pep:`517` is new, support is not universal, and frontends that
+      do support it may still have bugs. For compatibility, you may want to
+      put a ``setup.py`` file containing only a ``setuptools.setup()``
+      invocation.
+
 
 Using a ``src/`` layout
 =======================
@@ -2345,6 +2131,12 @@ Special directives:
 
 * ``attr:`` - Value is read from a module attribute.  ``attr:`` supports
   callables and iterables; unsupported types are cast using ``str()``.
+
+  In order to support the common case of a literal value assigned to a variable
+  in a module containing (directly or indirectly) third-party imports,
+  ``attr:`` first tries to read the value from the module by examining the
+  module's AST.  If that fails, ``attr:`` falls back to importing the module.
+
 * ``file:`` - Value is read from a list of files and then concatenated
 
 
@@ -2375,6 +2167,7 @@ maintainer_email                maintainer-email   str
 classifiers                     classifier         file:, list-comma
 license                                            str
 license_file                                       str
+license_files                                      list-comma
 description                     summary            file:, str
 long_description                long-description   file:, str
 long_description_content_type                      str                38.6.0
@@ -2416,7 +2209,7 @@ tests_require            list-semi
 include_package_data     bool
 packages                 find:, find_namespace:, list-comma
 package_dir              dict
-package_data             section
+package_data             section                                              (1)
 exclude_package_data     section
 namespace_packages       list-comma
 py_modules               list-comma
@@ -2433,6 +2226,10 @@ data_files               dict                                 40.6.0
 
     **find_namespace directive** - The ``find_namespace:`` directive is supported since Python >=3.3.
 
+Notes:
+1. In the `package_data` section, a key named with a single asterisk (`*`)
+refers to all packages, in lieu of the empty string used in `setup.py`.
+
 
 Configuration API
 =================
@@ -2447,7 +2244,7 @@ parsing ``metadata`` and ``options`` sections into a dictionary.
 
     from setuptools.config import read_configuration
 
-    conf_dict = read_configuration('/home/user/dev/package/setup.cfg')
+    conf_dict = read_configuration("/home/user/dev/package/setup.cfg")
 
 
 By default, ``read_configuration()`` will read only the file provided
@@ -2515,6 +2312,10 @@ script defines entry points for them!
 Adding ``setup()`` Arguments
 ----------------------------
 
+.. warning:: Adding arguments to setup is discouraged as such arguments
+   are only supported through imperative execution and not supported through
+   declarative config.
+
 Sometimes, your commands may need additional arguments to the ``setup()``
 call.  You can enable this by defining entry points in the
 ``distutils.setup_keywords`` group.  For example, if you wanted a ``setup()``
@@ -2566,6 +2367,25 @@ script using your extension lists your project in its ``setup_requires``
 argument.
 
 
+Customizing Distribution Options
+--------------------------------
+
+Plugins may wish to extend or alter the options on a Distribution object to
+suit the purposes of that project. For example, a tool that infers the
+``Distribution.version`` from SCM-metadata may need to hook into the
+option finalization. To enable this feature, Setuptools offers an entry
+point "setuptools.finalize_distribution_options". That entry point must
+be a callable taking one argument (the Distribution instance).
+
+If the callable has an ``.order`` property, that value will be used to
+determine the order in which the hook is called. Lower numbers are called
+first and the default is zero (0).
+
+Plugins may read, alter, and set properties on the distribution, but each
+plugin is encouraged to load the configuration/settings for their behavior
+independently.
+
+
 Adding new EGG-INFO Files
 -------------------------
 
@@ -2604,7 +2424,7 @@ a file.  Here's what the writer utility looks like::
         argname = os.path.splitext(basename)[0]
         value = getattr(cmd.distribution, argname, None)
         if value is not None:
-            value = '\n'.join(value) + '\n'
+            value = "\n".join(value) + "\n"
         cmd.write_or_delete_file(argname, filename, value)
 
 As you can see, ``egg_info.writers`` entry points must be a function taking
diff --git a/launcher.c b/launcher.c
index be69f0c6..23ef3ac2 100644
--- a/launcher.c
+++ b/launcher.c
@@ -37,6 +37,7 @@
 #include <windows.h>
 #include <tchar.h>
 #include <fcntl.h>
+#include <process.h>
 
 int child_pid=0;
 
diff --git a/netlify.toml b/netlify.toml
index ec21e7be..5828132e 100644
--- a/netlify.toml
+++ b/netlify.toml
@@ -1,5 +1,7 @@
 # Configuration for pull request documentation previews via Netlify
 
+# Netlify relies on there being a ./runtime.txt to indicate Python 3.
+
 [build]
-    publish = "docs/build/html"
+    publish = "build/html"
     command = "pip install tox && tox -e docs"
diff --git a/pkg_resources/__init__.py b/pkg_resources/__init__.py
index 1f170cfd..edd3d2e8 100644
--- a/pkg_resources/__init__.py
+++ b/pkg_resources/__init__.py
@@ -55,7 +55,7 @@ except NameError:
     FileExistsError = OSError
 
 from pkg_resources.extern import six
-from pkg_resources.extern.six.moves import urllib, map, filter
+from pkg_resources.extern.six.moves import map, filter
 
 # capture these to bypass sandboxing
 from os import utime
@@ -83,13 +83,14 @@ __import__('pkg_resources.extern.packaging.version')
 __import__('pkg_resources.extern.packaging.specifiers')
 __import__('pkg_resources.extern.packaging.requirements')
 __import__('pkg_resources.extern.packaging.markers')
+__import__('pkg_resources.py2_warn')
 
 
 __metaclass__ = type
 
 
-if (3, 0) < sys.version_info < (3, 4):
-    raise RuntimeError("Python 3.4 or later is required")
+if (3, 0) < sys.version_info < (3, 5):
+    raise RuntimeError("Python 3.5 or later is required")
 
 if six.PY2:
     # Those builtin exceptions are only defined in Python 3
@@ -178,10 +179,10 @@ def get_supported_platform():
     """Return this platform's maximum compatible version.
 
     distutils.util.get_platform() normally reports the minimum version
-    of Mac OS X that would be required to *use* extensions produced by
+    of macOS that would be required to *use* extensions produced by
     distutils.  But what we want when checking compatibility is to know the
-    version of Mac OS X that we are *running*.  To allow usage of packages that
-    explicitly require a newer version of Mac OS X, we must also know the
+    version of macOS that we are *running*.  To allow usage of packages that
+    explicitly require a newer version of macOS, we must also know the
     current version of the OS.
 
     If this condition occurs for any other platform with a version in its
@@ -191,9 +192,9 @@ def get_supported_platform():
     m = macosVersionString.match(plat)
     if m is not None and sys.platform == "darwin":
         try:
-            plat = 'macosx-%s-%s' % ('.'.join(_macosx_vers()[:2]), m.group(3))
+            plat = 'macosx-%s-%s' % ('.'.join(_macos_vers()[:2]), m.group(3))
         except ValueError:
-            # not Mac OS X
+            # not macOS
             pass
     return plat
 
@@ -333,7 +334,7 @@ class UnknownExtra(ResolutionError):
 
 _provider_factories = {}
 
-PY_MAJOR = sys.version[:3]
+PY_MAJOR = '{}.{}'.format(*sys.version_info)
 EGG_DIST = 3
 BINARY_DIST = 2
 SOURCE_DIST = 1
@@ -364,7 +365,7 @@ def get_provider(moduleOrReq):
     return _find_adapter(_provider_factories, loader)(module)
 
 
-def _macosx_vers(_cache=[]):
+def _macos_vers(_cache=[]):
     if not _cache:
         version = platform.mac_ver()[0]
         # fallback for MacPorts
@@ -380,7 +381,7 @@ def _macosx_vers(_cache=[]):
     return _cache[0]
 
 
-def _macosx_arch(machine):
+def _macos_arch(machine):
     return {'PowerPC': 'ppc', 'Power_Macintosh': 'ppc'}.get(machine, machine)
 
 
@@ -388,18 +389,18 @@ def get_build_platform():
     """Return this platform's string for platform-specific distributions
 
     XXX Currently this is the same as ``distutils.util.get_platform()``, but it
-    needs some hacks for Linux and Mac OS X.
+    needs some hacks for Linux and macOS.
     """
     from sysconfig import get_platform
 
     plat = get_platform()
     if sys.platform == "darwin" and not plat.startswith('macosx-'):
         try:
-            version = _macosx_vers()
+            version = _macos_vers()
             machine = os.uname()[4].replace(" ", "_")
             return "macosx-%d.%d-%s" % (
                 int(version[0]), int(version[1]),
-                _macosx_arch(machine),
+                _macos_arch(machine),
             )
         except ValueError:
             # if someone is running a non-Mac darwin system, this will fall
@@ -425,7 +426,7 @@ def compatible_platforms(provided, required):
         # easy case
         return True
 
-    # Mac OS X special cases
+    # macOS special cases
     reqMac = macosVersionString.match(required)
     if reqMac:
         provMac = macosVersionString.match(provided)
@@ -434,7 +435,7 @@ def compatible_platforms(provided, required):
         if not provMac:
             # this is backwards compatibility for packages built before
             # setuptools 0.6. All packages built after this point will
-            # use the new macosx designation.
+            # use the new macOS designation.
             provDarwin = darwinVersionString.match(provided)
             if provDarwin:
                 dversion = int(provDarwin.group(1))
@@ -442,7 +443,7 @@ def compatible_platforms(provided, required):
                 if dversion == 7 and macosversion >= "10.3" or \
                         dversion == 8 and macosversion >= "10.4":
                     return True
-            # egg isn't macosx or legacy darwin
+            # egg isn't macOS or legacy darwin
             return False
 
         # are they the same major version and machine type?
@@ -1234,12 +1235,13 @@ class ResourceManager:
         mode = os.stat(path).st_mode
         if mode & stat.S_IWOTH or mode & stat.S_IWGRP:
             msg = (
-                "%s is writable by group/others and vulnerable to attack "
-                "when "
-                "used with get_resource_filename. Consider a more secure "
+                "Extraction path is writable by group/others "
+                "and vulnerable to attack when "
+                "used with get_resource_filename ({path}). "
+                "Consider a more secure "
                 "location (set with .set_extraction_path or the "
-                "PYTHON_EGG_CACHE environment variable)." % path
-            )
+                "PYTHON_EGG_CACHE environment variable)."
+            ).format(**locals())
             warnings.warn(msg, UserWarning)
 
     def postprocess(self, tempname, filename):
@@ -2067,11 +2069,14 @@ def find_on_path(importer, path_item, only=False):
 
 
 def dist_factory(path_item, entry, only):
-    """
-    Return a dist_factory for a path_item and entry
-    """
+    """Return a dist_factory for the given entry."""
     lower = entry.lower()
-    is_meta = any(map(lower.endswith, ('.egg-info', '.dist-info')))
+    is_egg_info = lower.endswith('.egg-info')
+    is_dist_info = (
+        lower.endswith('.dist-info') and
+        os.path.isdir(os.path.join(path_item, entry))
+    )
+    is_meta = is_egg_info or is_dist_info
     return (
         distributions_from_metadata
         if is_meta else
@@ -2195,10 +2200,14 @@ def _handle_ns(packageName, path_item):
     if importer is None:
         return None
 
-    # capture warnings due to #1111
-    with warnings.catch_warnings():
-        warnings.simplefilter("ignore")
-        loader = importer.find_module(packageName)
+    # use find_spec (PEP 451) and fall-back to find_module (PEP 302)
+    try:
+        loader = importer.find_spec(packageName).loader
+    except AttributeError:
+        # capture warnings due to #1111
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore")
+            loader = importer.find_module(packageName)
 
     if loader is None:
         return None
@@ -2328,7 +2337,8 @@ register_namespace_handler(object, null_ns_handler)
 
 def normalize_path(filename):
     """Normalize a file/dir name for comparison purposes"""
-    return os.path.normcase(os.path.realpath(os.path.normpath(_cygwin_patch(filename))))
+    return os.path.normcase(os.path.realpath(os.path.normpath(
+        _cygwin_patch(filename))))
 
 
 def _cygwin_patch(filename):  # pragma: nocover
@@ -2536,15 +2546,6 @@ class EntryPoint:
         return maps
 
 
-def _remove_md5_fragment(location):
-    if not location:
-        return ''
-    parsed = urllib.parse.urlparse(location)
-    if parsed[-1].startswith('md5='):
-        return urllib.parse.urlunparse(parsed[:-1] + ('',))
-    return location
-
-
 def _version_from_file(lines):
     """
     Given an iterable of lines from a Metadata file, return
@@ -2601,7 +2602,7 @@ class Distribution:
             self.parsed_version,
             self.precedence,
             self.key,
-            _remove_md5_fragment(self.location),
+            self.location,
             self.py_version or '',
             self.platform or '',
         )
@@ -3109,6 +3110,7 @@ class Requirement(packaging.requirements.Requirement):
         self.extras = tuple(map(safe_extra, self.extras))
         self.hashCmp = (
             self.key,
+            self.url,
             self.specifier,
             frozenset(self.extras),
             str(self.marker) if self.marker else None,
@@ -3286,6 +3288,7 @@ def _initialize_master_working_set():
     list(map(working_set.add_entry, sys.path))
     globals().update(locals())
 
+
 class PkgResourcesDeprecationWarning(Warning):
     """
     Base class for warning about deprecations in ``pkg_resources``
diff --git a/pkg_resources/api_tests.txt b/pkg_resources/api_tests.txt
index 0a75170e..ded18800 100644
--- a/pkg_resources/api_tests.txt
+++ b/pkg_resources/api_tests.txt
@@ -36,7 +36,7 @@ Distributions have various introspectable attributes::
     >>> dist.version
     '0.9'
 
-    >>> dist.py_version == sys.version[:3]
+    >>> dist.py_version == '{}.{}'.format(*sys.version_info)
     True
 
     >>> print(dist.platform)
@@ -290,8 +290,8 @@ Platform Compatibility Rules
 ----------------------------
 
 On the Mac, there are potential compatibility issues for modules compiled
-on newer versions of Mac OS X than what the user is running. Additionally,
-Mac OS X will soon have two platforms to contend with: Intel and PowerPC.
+on newer versions of macOS than what the user is running. Additionally,
+macOS will soon have two platforms to contend with: Intel and PowerPC.
 
 Basic equality works as on other platforms::
 
diff --git a/pkg_resources/extern/__init__.py b/pkg_resources/extern/__init__.py
index c1eb9e99..bf98d8f2 100644
--- a/pkg_resources/extern/__init__.py
+++ b/pkg_resources/extern/__init__.py
@@ -43,13 +43,6 @@ class VendorImporter:
                 __import__(extant)
                 mod = sys.modules[extant]
                 sys.modules[fullname] = mod
-                # mysterious hack:
-                # Remove the reference to the extant package/module
-                # on later Python versions to cause relative imports
-                # in the vendor package to resolve the same modules
-                # as those going through this importer.
-                if prefix and sys.version_info > (3, 3):
-                    del sys.modules[extant]
                 return mod
             except ImportError:
                 pass
diff --git a/pkg_resources/py2_warn.py b/pkg_resources/py2_warn.py
new file mode 100644
index 00000000..bfc35234
--- /dev/null
+++ b/pkg_resources/py2_warn.py
@@ -0,0 +1,21 @@
+import sys
+import warnings
+import textwrap
+
+
+msg = textwrap.dedent("""
+    You are running Setuptools on Python 2, which is no longer
+    supported and
+    >>> SETUPTOOLS WILL STOP WORKING <<<
+    in a subsequent release (no sooner than 2020-04-20).
+    Please ensure you are installing
+    Setuptools using pip 9.x or later or pin to `setuptools<45`
+    in your environment.
+    If you have done those things and are still encountering
+    this message, please follow up at
+    https://bit.ly/setuptools-py2-warning.
+    """)
+
+pre = "Setuptools will stop working on Python 2\n"
+
+sys.version_info < (3,) and warnings.warn(pre + "*" * 60 + msg + "*" * 60)
diff --git a/pkg_resources/tests/data/my-test-package-source/setup.cfg b/pkg_resources/tests/data/my-test-package-source/setup.cfg
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package-source/setup.cfg
diff --git a/pkg_resources/tests/data/my-test-package-source/setup.py b/pkg_resources/tests/data/my-test-package-source/setup.py
new file mode 100644
index 00000000..fe80d28f
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package-source/setup.py
@@ -0,0 +1,6 @@
+import setuptools
+setuptools.setup(
+    name="my-test-package",
+    version="1.0",
+    zip_safe=True,
+)
diff --git a/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/PKG-INFO b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/PKG-INFO
new file mode 100644
index 00000000..7328e3f7
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/PKG-INFO
@@ -0,0 +1,10 @@
+Metadata-Version: 1.0
+Name: my-test-package
+Version: 1.0
+Summary: UNKNOWN
+Home-page: UNKNOWN
+Author: UNKNOWN
+Author-email: UNKNOWN
+License: UNKNOWN
+Description: UNKNOWN
+Platform: UNKNOWN
diff --git a/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/SOURCES.txt b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/SOURCES.txt
new file mode 100644
index 00000000..3c4ee167
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/SOURCES.txt
@@ -0,0 +1,7 @@
+setup.cfg
+setup.py
+my_test_package.egg-info/PKG-INFO
+my_test_package.egg-info/SOURCES.txt
+my_test_package.egg-info/dependency_links.txt
+my_test_package.egg-info/top_level.txt
+my_test_package.egg-info/zip-safe
\ No newline at end of file
diff --git a/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/dependency_links.txt b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/dependency_links.txt
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/dependency_links.txt
@@ -0,0 +1 @@
+
diff --git a/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/top_level.txt b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/top_level.txt
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/top_level.txt
@@ -0,0 +1 @@
+
diff --git a/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/zip-safe b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/zip-safe
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package_unpacked-egg/my_test_package-1.0-py3.7.egg/EGG-INFO/zip-safe
@@ -0,0 +1 @@
+
diff --git a/pkg_resources/tests/data/my-test-package_zipped-egg/my_test_package-1.0-py3.7.egg b/pkg_resources/tests/data/my-test-package_zipped-egg/my_test_package-1.0-py3.7.egg
new file mode 100644
index 00000000..5115b895
--- /dev/null
+++ b/pkg_resources/tests/data/my-test-package_zipped-egg/my_test_package-1.0-py3.7.egg
diff --git a/pkg_resources/tests/test_find_distributions.py b/pkg_resources/tests/test_find_distributions.py
index d735c590..f9594422 100644
--- a/pkg_resources/tests/test_find_distributions.py
+++ b/pkg_resources/tests/test_find_distributions.py
@@ -1,17 +1,9 @@
-import subprocess
-import sys
-
+import py
 import pytest
 import pkg_resources
 
-SETUP_TEMPLATE = """
-import setuptools
-setuptools.setup(
-    name="my-test-package",
-    version="1.0",
-    zip_safe=True,
-)
-""".lstrip()
+
+TESTS_DATA_DIR = py.path.local(__file__).dirpath('data')
 
 
 class TestFindDistributions:
@@ -21,46 +13,22 @@ class TestFindDistributions:
         target_dir = tmpdir.mkdir('target')
         # place a .egg named directory in the target that is not an egg:
         target_dir.mkdir('not.an.egg')
-        return str(target_dir)
-
-    @pytest.fixture
-    def project_dir(self, tmpdir):
-        project_dir = tmpdir.mkdir('my-test-package')
-        (project_dir / "setup.py").write(SETUP_TEMPLATE)
-        return str(project_dir)
+        return target_dir
 
     def test_non_egg_dir_named_egg(self, target_dir):
-        dists = pkg_resources.find_distributions(target_dir)
+        dists = pkg_resources.find_distributions(str(target_dir))
         assert not list(dists)
 
-    def test_standalone_egg_directory(self, project_dir, target_dir):
-        # install this distro as an unpacked egg:
-        args = [
-            sys.executable,
-            '-c', 'from setuptools.command.easy_install import main; main()',
-            '-mNx',
-            '-d', target_dir,
-            '--always-unzip',
-            project_dir,
-        ]
-        subprocess.check_call(args)
-        dists = pkg_resources.find_distributions(target_dir)
+    def test_standalone_egg_directory(self, target_dir):
+        (TESTS_DATA_DIR / 'my-test-package_unpacked-egg').copy(target_dir)
+        dists = pkg_resources.find_distributions(str(target_dir))
         assert [dist.project_name for dist in dists] == ['my-test-package']
-        dists = pkg_resources.find_distributions(target_dir, only=True)
+        dists = pkg_resources.find_distributions(str(target_dir), only=True)
         assert not list(dists)
 
-    def test_zipped_egg(self, project_dir, target_dir):
-        # install this distro as an unpacked egg:
-        args = [
-            sys.executable,
-            '-c', 'from setuptools.command.easy_install import main; main()',
-            '-mNx',
-            '-d', target_dir,
-            '--zip-ok',
-            project_dir,
-        ]
-        subprocess.check_call(args)
-        dists = pkg_resources.find_distributions(target_dir)
+    def test_zipped_egg(self, target_dir):
+        (TESTS_DATA_DIR / 'my-test-package_zipped-egg').copy(target_dir)
+        dists = pkg_resources.find_distributions(str(target_dir))
         assert [dist.project_name for dist in dists] == ['my-test-package']
-        dists = pkg_resources.find_distributions(target_dir, only=True)
+        dists = pkg_resources.find_distributions(str(target_dir), only=True)
         assert not list(dists)
diff --git a/pkg_resources/tests/test_pkg_resources.py b/pkg_resources/tests/test_pkg_resources.py
index 5960868a..189a8668 100644
--- a/pkg_resources/tests/test_pkg_resources.py
+++ b/pkg_resources/tests/test_pkg_resources.py
@@ -17,7 +17,9 @@ try:
 except ImportError:
     import mock
 
-from pkg_resources import DistInfoDistribution, Distribution, EggInfoDistribution
+from pkg_resources import (
+    DistInfoDistribution, Distribution, EggInfoDistribution,
+)
 from setuptools.extern import six
 from pkg_resources.extern.six.moves import map
 from pkg_resources.extern.six import text_type, string_types
@@ -279,8 +281,8 @@ def make_distribution_no_version(tmpdir, basename):
         ('dist-info', 'METADATA', DistInfoDistribution),
     ],
 )
-def test_distribution_version_missing(tmpdir, suffix, expected_filename,
-    expected_dist_type):
+def test_distribution_version_missing(
+        tmpdir, suffix, expected_filename, expected_dist_type):
     """
     Test Distribution.version when the "Version" header is missing.
     """
@@ -328,6 +330,14 @@ def test_distribution_version_missing_undetected_path():
     assert msg == expected
 
 
+@pytest.mark.parametrize('only', [False, True])
+def test_dist_info_is_not_dir(tmp_path, only):
+    """Test path containing a file with dist-info extension."""
+    dist_info = tmp_path / 'foobar.dist-info'
+    dist_info.touch()
+    assert not pkg_resources.dist_factory(str(tmp_path), str(dist_info), only)
+
+
 class TestDeepVersionLookupDistutils:
     @pytest.fixture
     def env(self, tmpdir):
diff --git a/pkg_resources/tests/test_resources.py b/pkg_resources/tests/test_resources.py
index 86afcf74..ed7cdfcc 100644
--- a/pkg_resources/tests/test_resources.py
+++ b/pkg_resources/tests/test_resources.py
@@ -15,7 +15,7 @@ import pkg_resources
 from pkg_resources import (
     parse_requirements, VersionConflict, parse_version,
     Distribution, EntryPoint, Requirement, safe_version, safe_name,
-    WorkingSet, PkgResourcesDeprecationWarning)
+    WorkingSet)
 
 
 # from Python 3.6 docs.
@@ -116,7 +116,7 @@ class TestDistro:
         self.checkFooPkg(d)
 
         d = Distribution("/some/path")
-        assert d.py_version == sys.version[:3]
+        assert d.py_version == '{}.{}'.format(*sys.version_info)
         assert d.platform is None
 
     def testDistroParse(self):
@@ -501,7 +501,6 @@ class TestEntryPoints:
             ep.load(require=False)
 
 
-
 class TestRequirements:
     def testBasics(self):
         r = Requirement.parse("Twisted>=1.2")
@@ -520,6 +519,11 @@ class TestRequirements:
         assert r1 == r2
         assert str(r1) == str(r2)
         assert str(r2) == "Twisted==1.2c1,>=1.2"
+        assert (
+            Requirement("Twisted")
+            !=
+            Requirement("Twisted @ https://localhost/twisted.zip")
+        )
 
     def testBasicContains(self):
         r = Requirement("Twisted>=1.2")
@@ -546,11 +550,23 @@ class TestRequirements:
             ==
             hash((
                 "twisted",
+                None,
                 packaging.specifiers.SpecifierSet(">=1.2"),
                 frozenset(["foo", "bar"]),
                 None
             ))
         )
+        assert (
+            hash(Requirement.parse("Twisted @ https://localhost/twisted.zip"))
+            ==
+            hash((
+                "twisted",
+                "https://localhost/twisted.zip",
+                packaging.specifiers.SpecifierSet(),
+                frozenset(),
+                None
+            ))
+        )
 
     def testVersionEquality(self):
         r1 = Requirement.parse("foo==0.3a2")
diff --git a/pkg_resources/tests/test_working_set.py b/pkg_resources/tests/test_working_set.py
index b3ca4ea8..7a759bbb 100644
--- a/pkg_resources/tests/test_working_set.py
+++ b/pkg_resources/tests/test_working_set.py
@@ -14,8 +14,8 @@ __metaclass__ = type
 
 def strip_comments(s):
     return '\n'.join(
-        l for l in s.split('\n')
-        if l.strip() and not l.strip().startswith('#')
+        line for line in s.split('\n')
+        if line.strip() and not line.strip().startswith('#')
     )
 
 
diff --git a/pyproject.toml b/pyproject.toml
index 07c23bb5..cfdc2574 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,11 @@
 [build-system]
-requires = ["wheel"]
+requires = [
+    # avoid self install on Python 2; ref #1996
+    "setuptools >= 40.8; python_version > '3'",
+    "wheel",
+]
+build-backend = "setuptools.build_meta"
+backend-path = ["."]
 
 [tool.towncrier]
     package = "setuptools"
diff --git a/pytest.ini b/pytest.ini
index 612fb91f..479a2965 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,7 +1,25 @@
 [pytest]
-addopts=--doctest-modules --doctest-glob=pkg_resources/api_tests.txt -r sxX
-norecursedirs=dist build *.egg setuptools/extern pkg_resources/extern .*
-flake8-ignore =
-    setuptools/site-patch.py F821
-    setuptools/py*compat.py F811
+addopts=--doctest-modules --flake8 --doctest-glob=pkg_resources/api_tests.txt -r sxX
+norecursedirs=dist build *.egg setuptools/extern pkg_resources/extern pkg_resources/tests/data tools .* setuptools/_vendor pkg_resources/_vendor
 doctest_optionflags=ELLIPSIS ALLOW_UNICODE
+filterwarnings =
+    # Fail on warnings
+    error
+    # https://github.com/pypa/setuptools/issues/1823
+    ignore:bdist_wininst command is deprecated
+    # Suppress this error; unimportant for CI tests
+    ignore:Extraction path is writable by group/others:UserWarning
+    # Suppress Python 2 deprecation warning
+    ignore:Setuptools will stop working on Python 2:UserWarning
+    # Suppress weird RuntimeWarning.
+    ignore:Parent module 'setuptools' not found while handling absolute import:RuntimeWarning
+    # Suppress use of bytes for filenames on Windows until fixed #2016
+    ignore:The Windows bytes API has been deprecated:DeprecationWarning
+    # Suppress other Python 2 UnicodeWarnings
+    ignore:Unicode equal comparison failed to convert:UnicodeWarning
+    ignore:Unicode unequal comparison failed to convert:UnicodeWarning
+    # https://github.com/pypa/setuptools/issues/2025
+    ignore:direct construction of .*Item has been deprecated:DeprecationWarning
+    # https://github.com/pypa/setuptools/issues/2081
+    ignore:lib2to3 package is deprecated:PendingDeprecationWarning
+    ignore:lib2to3 package is deprecated:DeprecationWarning
diff --git a/runtime.txt b/runtime.txt
new file mode 100644
index 00000000..475ba515
--- /dev/null
+++ b/runtime.txt
@@ -0,0 +1 @@
+3.7
diff --git a/setup.cfg b/setup.cfg
index ff87464b..72d4dce9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -14,12 +14,9 @@ repository = https://upload.pypi.org/legacy/
 [sdist]
 formats = zip
 
-[bdist_wheel]
-universal = 1
-
 [metadata]
 name = setuptools
-version = 41.0.1
+version = 46.4.0
 description = Easily download, build, install, upgrade, and uninstall Python packages
 author = Python Packaging Authority
 author_email = distutils-sig@python.org
@@ -35,13 +32,12 @@ classifiers =
     Intended Audience :: Developers
     License :: OSI Approved :: MIT License
     Operating System :: OS Independent
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.4
+    Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3.5
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
     Topic :: Software Development :: Libraries :: Python Modules
     Topic :: System :: Archiving :: Packaging
     Topic :: System :: Systems Administration
@@ -49,7 +45,7 @@ classifiers =
 
 [options]
 zip_safe = True
-python_requires = >=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*
+python_requires = >=3.5
 py_modules = easy_install
 packages = find:
 
@@ -59,5 +55,27 @@ exclude = *.tests
 [options.extras_require]
 ssl =
     wincertstore==0.2; sys_platform=='win32'
+
 certs =
     certifi==2016.9.26
+
+tests =
+    mock
+    pytest-flake8
+    flake8-2020; python_version>="3.6"
+    virtualenv>=13.0.0
+    pytest-virtualenv>=1.2.7
+    pytest>=3.7
+    wheel
+    coverage>=4.5.1
+    pytest-cov>=2.5.1
+    paver; python_version>="3.6"
+    futures; python_version=="2.7"
+    pip>=19.1 # For proper file:// URLs support.
+
+docs =
+    # Keep these in sync with docs/requirements.txt
+    sphinx
+    jaraco.packaging>=6.1
+    rst.linker>=1.9
+    pygments-github-lexers==0.0.5
diff --git a/setup.py b/setup.py
index f5030dd6..1fe18bd1 100755
--- a/setup.py
+++ b/setup.py
@@ -44,7 +44,7 @@ def _gen_console_scripts():
     if any(os.environ.get(var) not in (None, "", "0") for var in var_names):
         return
     tmpl = "easy_install-{shortver} = setuptools.command.easy_install:main"
-    yield tmpl.format(shortver=sys.version[:3])
+    yield tmpl.format(shortver='{}.{}'.format(*sys.version_info))
 
 
 package_data = dict(
@@ -89,6 +89,12 @@ setup_params = dict(
             "%(cmd)s = setuptools.command.%(cmd)s:%(cmd)s" % locals()
             for cmd in read_commands()
         ],
+        "setuptools.finalize_distribution_options": [
+            "parent_finalize = setuptools.dist:_Distribution.finalize_options",
+            "keywords = setuptools.dist:Distribution._finalize_setup_keywords",
+            "2to3_doctests = "
+            "setuptools.dist:Distribution._finalize_2to3_doctests",
+        ],
         "distutils.setup_keywords": [
             "eager_resources        = setuptools.dist:assert_string_list",
             "namespace_packages     = setuptools.dist:check_nsp",
diff --git a/setuptools/__init__.py b/setuptools/__init__.py
index a71b2bbd..811f3fd2 100644
--- a/setuptools/__init__.py
+++ b/setuptools/__init__.py
@@ -1,7 +1,6 @@
 """Extensions to the 'distutils' for large or complex distributions"""
 
 import os
-import sys
 import functools
 import distutils.core
 import distutils.filelist
@@ -17,7 +16,7 @@ from setuptools.extern.six.moves import filter, map
 
 import setuptools.version
 from setuptools.extension import Extension
-from setuptools.dist import Distribution, Feature
+from setuptools.dist import Distribution
 from setuptools.depends import Require
 from . import monkey
 
@@ -25,13 +24,13 @@ __metaclass__ = type
 
 
 __all__ = [
-    'setup', 'Distribution', 'Feature', 'Command', 'Extension', 'Require',
+    'setup', 'Distribution', 'Command', 'Extension', 'Require',
     'SetuptoolsDeprecationWarning',
     'find_packages'
 ]
 
 if PY3:
-  __all__.append('find_namespace_packages')
+    __all__.append('find_namespace_packages')
 
 __version__ = setuptools.version.__version__
 
@@ -123,7 +122,7 @@ class PEP420PackageFinder(PackageFinder):
 find_packages = PackageFinder.find
 
 if PY3:
-  find_namespace_packages = PEP420PackageFinder.find
+    find_namespace_packages = PEP420PackageFinder.find
 
 
 def _install_setup_requires(attrs):
@@ -144,6 +143,7 @@ def setup(**attrs):
     _install_setup_requires(attrs)
     return distutils.core.setup(**attrs)
 
+
 setup.__doc__ = distutils.core.setup.__doc__
 
 
@@ -191,8 +191,8 @@ class Command(_Command):
                 ok = False
             if not ok:
                 raise DistutilsOptionError(
-                      "'%s' must be a list of strings (got %r)"
-                      % (option, val))
+                    "'%s' must be a list of strings (got %r)"
+                    % (option, val))
 
     def reinitialize_command(self, command, reinit_subcommands=0, **kw):
         cmd = _Command.reinitialize_command(self, command, reinit_subcommands)
@@ -224,5 +224,9 @@ def findall(dir=os.curdir):
     return list(files)
 
 
+class sic(str):
+    """Treat this string as-is (https://en.wikipedia.org/wiki/Sic)"""
+
+
 # Apply monkey patches
 monkey.patch_all()
diff --git a/setuptools/_imp.py b/setuptools/_imp.py
new file mode 100644
index 00000000..451e45a8
--- /dev/null
+++ b/setuptools/_imp.py
@@ -0,0 +1,82 @@
+"""
+Re-implementation of find_module and get_frozen_object
+from the deprecated imp module.
+"""
+
+import os
+import importlib.util
+import importlib.machinery
+
+from .py34compat import module_from_spec
+
+
+PY_SOURCE = 1
+PY_COMPILED = 2
+C_EXTENSION = 3
+C_BUILTIN = 6
+PY_FROZEN = 7
+
+
+def find_spec(module, paths):
+    finder = (
+        importlib.machinery.PathFinder().find_spec
+        if isinstance(paths, list) else
+        importlib.util.find_spec
+    )
+    return finder(module, paths)
+
+
+def find_module(module, paths=None):
+    """Just like 'imp.find_module()', but with package support"""
+    spec = find_spec(module, paths)
+    if spec is None:
+        raise ImportError("Can't find %s" % module)
+    if not spec.has_location and hasattr(spec, 'submodule_search_locations'):
+        spec = importlib.util.spec_from_loader('__init__.py', spec.loader)
+
+    kind = -1
+    file = None
+    static = isinstance(spec.loader, type)
+    if spec.origin == 'frozen' or static and issubclass(
+            spec.loader, importlib.machinery.FrozenImporter):
+        kind = PY_FROZEN
+        path = None  # imp compabilty
+        suffix = mode = ''  # imp compability
+    elif spec.origin == 'built-in' or static and issubclass(
+            spec.loader, importlib.machinery.BuiltinImporter):
+        kind = C_BUILTIN
+        path = None  # imp compabilty
+        suffix = mode = ''  # imp compability
+    elif spec.has_location:
+        path = spec.origin
+        suffix = os.path.splitext(path)[1]
+        mode = 'r' if suffix in importlib.machinery.SOURCE_SUFFIXES else 'rb'
+
+        if suffix in importlib.machinery.SOURCE_SUFFIXES:
+            kind = PY_SOURCE
+        elif suffix in importlib.machinery.BYTECODE_SUFFIXES:
+            kind = PY_COMPILED
+        elif suffix in importlib.machinery.EXTENSION_SUFFIXES:
+            kind = C_EXTENSION
+
+        if kind in {PY_SOURCE, PY_COMPILED}:
+            file = open(path, mode)
+    else:
+        path = None
+        suffix = mode = ''
+
+    return file, path, (suffix, mode, kind)
+
+
+def get_frozen_object(module, paths=None):
+    spec = find_spec(module, paths)
+    if not spec:
+        raise ImportError("Can't find %s" % module)
+    return spec.loader.get_code(module)
+
+
+def get_module(module, paths, info):
+    spec = find_spec(module, paths)
+    if not spec:
+        raise ImportError("Can't find %s" % module)
+    return module_from_spec(spec)
diff --git a/setuptools/_vendor/ordered_set.py b/setuptools/_vendor/ordered_set.py
new file mode 100644
index 00000000..14876000
--- /dev/null
+++ b/setuptools/_vendor/ordered_set.py
@@ -0,0 +1,488 @@
+"""
+An OrderedSet is a custom MutableSet that remembers its order, so that every
+entry has an index that can be looked up.
+
+Based on a recipe originally posted to ActiveState Recipes by Raymond Hettiger,
+and released under the MIT license.
+"""
+import itertools as it
+from collections import deque
+
+try:
+    # Python 3
+    from collections.abc import MutableSet, Sequence
+except ImportError:
+    # Python 2.7
+    from collections import MutableSet, Sequence
+
+SLICE_ALL = slice(None)
+__version__ = "3.1"
+
+
+def is_iterable(obj):
+    """
+    Are we being asked to look up a list of things, instead of a single thing?
+    We check for the `__iter__` attribute so that this can cover types that
+    don't have to be known by this module, such as NumPy arrays.
+
+    Strings, however, should be considered as atomic values to look up, not
+    iterables. The same goes for tuples, since they are immutable and therefore
+    valid entries.
+
+    We don't need to check for the Python 2 `unicode` type, because it doesn't
+    have an `__iter__` attribute anyway.
+    """
+    return (
+        hasattr(obj, "__iter__")
+        and not isinstance(obj, str)
+        and not isinstance(obj, tuple)
+    )
+
+
+class OrderedSet(MutableSet, Sequence):
+    """
+    An OrderedSet is a custom MutableSet that remembers its order, so that
+    every entry has an index that can be looked up.
+
+    Example:
+        >>> OrderedSet([1, 1, 2, 3, 2])
+        OrderedSet([1, 2, 3])
+    """
+
+    def __init__(self, iterable=None):
+        self.items = []
+        self.map = {}
+        if iterable is not None:
+            self |= iterable
+
+    def __len__(self):
+        """
+        Returns the number of unique elements in the ordered set
+
+        Example:
+            >>> len(OrderedSet([]))
+            0
+            >>> len(OrderedSet([1, 2]))
+            2
+        """
+        return len(self.items)
+
+    def __getitem__(self, index):
+        """
+        Get the item at a given index.
+
+        If `index` is a slice, you will get back that slice of items, as a
+        new OrderedSet.
+
+        If `index` is a list or a similar iterable, you'll get a list of
+        items corresponding to those indices. This is similar to NumPy's
+        "fancy indexing". The result is not an OrderedSet because you may ask
+        for duplicate indices, and the number of elements returned should be
+        the number of elements asked for.
+
+        Example:
+            >>> oset = OrderedSet([1, 2, 3])
+            >>> oset[1]
+            2
+        """
+        if isinstance(index, slice) and index == SLICE_ALL:
+            return self.copy()
+        elif is_iterable(index):
+            return [self.items[i] for i in index]
+        elif hasattr(index, "__index__") or isinstance(index, slice):
+            result = self.items[index]
+            if isinstance(result, list):
+                return self.__class__(result)
+            else:
+                return result
+        else:
+            raise TypeError("Don't know how to index an OrderedSet by %r" % index)
+
+    def copy(self):
+        """
+        Return a shallow copy of this object.
+
+        Example:
+            >>> this = OrderedSet([1, 2, 3])
+            >>> other = this.copy()
+            >>> this == other
+            True
+            >>> this is other
+            False
+        """
+        return self.__class__(self)
+
+    def __getstate__(self):
+        if len(self) == 0:
+            # The state can't be an empty list.
+            # We need to return a truthy value, or else __setstate__ won't be run.
+            #
+            # This could have been done more gracefully by always putting the state
+            # in a tuple, but this way is backwards- and forwards- compatible with
+            # previous versions of OrderedSet.
+            return (None,)
+        else:
+            return list(self)
+
+    def __setstate__(self, state):
+        if state == (None,):
+            self.__init__([])
+        else:
+            self.__init__(state)
+
+    def __contains__(self, key):
+        """
+        Test if the item is in this ordered set
+
+        Example:
+            >>> 1 in OrderedSet([1, 3, 2])
+            True
+            >>> 5 in OrderedSet([1, 3, 2])
+            False
+        """
+        return key in self.map
+
+    def add(self, key):
+        """
+        Add `key` as an item to this OrderedSet, then return its index.
+
+        If `key` is already in the OrderedSet, return the index it already
+        had.
+
+        Example:
+            >>> oset = OrderedSet()
+            >>> oset.append(3)
+            0
+            >>> print(oset)
+            OrderedSet([3])
+        """
+        if key not in self.map:
+            self.map[key] = len(self.items)
+            self.items.append(key)
+        return self.map[key]
+
+    append = add
+
+    def update(self, sequence):
+        """
+        Update the set with the given iterable sequence, then return the index
+        of the last element inserted.
+
+        Example:
+            >>> oset = OrderedSet([1, 2, 3])
+            >>> oset.update([3, 1, 5, 1, 4])
+            4
+            >>> print(oset)
+            OrderedSet([1, 2, 3, 5, 4])
+        """
+        item_index = None
+        try:
+            for item in sequence:
+                item_index = self.add(item)
+        except TypeError:
+            raise ValueError(
+                "Argument needs to be an iterable, got %s" % type(sequence)
+            )
+        return item_index
+
+    def index(self, key):
+        """
+        Get the index of a given entry, raising an IndexError if it's not
+        present.
+
+        `key` can be an iterable of entries that is not a string, in which case
+        this returns a list of indices.
+
+        Example:
+            >>> oset = OrderedSet([1, 2, 3])
+            >>> oset.index(2)
+            1
+        """
+        if is_iterable(key):
+            return [self.index(subkey) for subkey in key]
+        return self.map[key]
+
+    # Provide some compatibility with pd.Index
+    get_loc = index
+    get_indexer = index
+
+    def pop(self):
+        """
+        Remove and return the last element from the set.
+
+        Raises KeyError if the set is empty.
+
+        Example:
+            >>> oset = OrderedSet([1, 2, 3])
+            >>> oset.pop()
+            3
+        """
+        if not self.items:
+            raise KeyError("Set is empty")
+
+        elem = self.items[-1]
+        del self.items[-1]
+        del self.map[elem]
+        return elem
+
+    def discard(self, key):
+        """
+        Remove an element.  Do not raise an exception if absent.
+
+        The MutableSet mixin uses this to implement the .remove() method, which
+        *does* raise an error when asked to remove a non-existent item.
+
+        Example:
+            >>> oset = OrderedSet([1, 2, 3])
+            >>> oset.discard(2)
+            >>> print(oset)
+            OrderedSet([1, 3])
+            >>> oset.discard(2)
+            >>> print(oset)
+            OrderedSet([1, 3])
+        """
+        if key in self:
+            i = self.map[key]
+            del self.items[i]
+            del self.map[key]
+            for k, v in self.map.items():
+                if v >= i:
+                    self.map[k] = v - 1
+
+    def clear(self):
+        """
+        Remove all items from this OrderedSet.
+        """
+        del self.items[:]
+        self.map.clear()
+
+    def __iter__(self):
+        """
+        Example:
+            >>> list(iter(OrderedSet([1, 2, 3])))
+            [1, 2, 3]
+        """
+        return iter(self.items)
+
+    def __reversed__(self):
+        """
+        Example:
+            >>> list(reversed(OrderedSet([1, 2, 3])))
+            [3, 2, 1]
+        """
+        return reversed(self.items)
+
+    def __repr__(self):
+        if not self:
+            return "%s()" % (self.__class__.__name__,)
+        return "%s(%r)" % (self.__class__.__name__, list(self))
+
+    def __eq__(self, other):
+        """
+        Returns true if the containers have the same items. If `other` is a
+        Sequence, then order is checked, otherwise it is ignored.
+
+        Example:
+            >>> oset = OrderedSet([1, 3, 2])
+            >>> oset == [1, 3, 2]
+            True
+            >>> oset == [1, 2, 3]
+            False
+            >>> oset == [2, 3]
+            False
+            >>> oset == OrderedSet([3, 2, 1])
+            False
+        """
+        # In Python 2 deque is not a Sequence, so treat it as one for
+        # consistent behavior with Python 3.
+        if isinstance(other, (Sequence, deque)):
+            # Check that this OrderedSet contains the same elements, in the
+            # same order, as the other object.
+            return list(self) == list(other)
+        try:
+            other_as_set = set(other)
+        except TypeError:
+            # If `other` can't be converted into a set, it's not equal.
+            return False
+        else:
+            return set(self) == other_as_set
+
+    def union(self, *sets):
+        """
+        Combines all unique items.
+        Each items order is defined by its first appearance.
+
+        Example:
+            >>> oset = OrderedSet.union(OrderedSet([3, 1, 4, 1, 5]), [1, 3], [2, 0])
+            >>> print(oset)
+            OrderedSet([3, 1, 4, 5, 2, 0])
+            >>> oset.union([8, 9])
+            OrderedSet([3, 1, 4, 5, 2, 0, 8, 9])
+            >>> oset | {10}
+            OrderedSet([3, 1, 4, 5, 2, 0, 10])
+        """
+        cls = self.__class__ if isinstance(self, OrderedSet) else OrderedSet
+        containers = map(list, it.chain([self], sets))
+        items = it.chain.from_iterable(containers)
+        return cls(items)
+
+    def __and__(self, other):
+        # the parent implementation of this is backwards
+        return self.intersection(other)
+
+    def intersection(self, *sets):
+        """
+        Returns elements in common between all sets. Order is defined only
+        by the first set.
+
+        Example:
+            >>> oset = OrderedSet.intersection(OrderedSet([0, 1, 2, 3]), [1, 2, 3])
+            >>> print(oset)
+            OrderedSet([1, 2, 3])
+            >>> oset.intersection([2, 4, 5], [1, 2, 3, 4])
+            OrderedSet([2])
+            >>> oset.intersection()
+            OrderedSet([1, 2, 3])
+        """
+        cls = self.__class__ if isinstance(self, OrderedSet) else OrderedSet
+        if sets:
+            common = set.intersection(*map(set, sets))
+            items = (item for item in self if item in common)
+        else:
+            items = self
+        return cls(items)
+
+    def difference(self, *sets):
+        """
+        Returns all elements that are in this set but not the others.
+
+        Example:
+            >>> OrderedSet([1, 2, 3]).difference(OrderedSet([2]))
+            OrderedSet([1, 3])
+            >>> OrderedSet([1, 2, 3]).difference(OrderedSet([2]), OrderedSet([3]))
+            OrderedSet([1])
+            >>> OrderedSet([1, 2, 3]) - OrderedSet([2])
+            OrderedSet([1, 3])
+            >>> OrderedSet([1, 2, 3]).difference()
+            OrderedSet([1, 2, 3])
+        """
+        cls = self.__class__
+        if sets:
+            other = set.union(*map(set, sets))
+            items = (item for item in self if item not in other)
+        else:
+            items = self
+        return cls(items)
+
+    def issubset(self, other):
+        """
+        Report whether another set contains this set.
+
+        Example:
+            >>> OrderedSet([1, 2, 3]).issubset({1, 2})
+            False
+            >>> OrderedSet([1, 2, 3]).issubset({1, 2, 3, 4})
+            True
+            >>> OrderedSet([1, 2, 3]).issubset({1, 4, 3, 5})
+            False
+        """
+        if len(self) > len(other):  # Fast check for obvious cases
+            return False
+        return all(item in other for item in self)
+
+    def issuperset(self, other):
+        """
+        Report whether this set contains another set.
+
+        Example:
+            >>> OrderedSet([1, 2]).issuperset([1, 2, 3])
+            False
+            >>> OrderedSet([1, 2, 3, 4]).issuperset({1, 2, 3})
+            True
+            >>> OrderedSet([1, 4, 3, 5]).issuperset({1, 2, 3})
+            False
+        """
+        if len(self) < len(other):  # Fast check for obvious cases
+            return False
+        return all(item in self for item in other)
+
+    def symmetric_difference(self, other):
+        """
+        Return the symmetric difference of two OrderedSets as a new set.
+        That is, the new set will contain all elements that are in exactly
+        one of the sets.
+
+        Their order will be preserved, with elements from `self` preceding
+        elements from `other`.
+
+        Example:
+            >>> this = OrderedSet([1, 4, 3, 5, 7])
+            >>> other = OrderedSet([9, 7, 1, 3, 2])
+            >>> this.symmetric_difference(other)
+            OrderedSet([4, 5, 9, 2])
+        """
+        cls = self.__class__ if isinstance(self, OrderedSet) else OrderedSet
+        diff1 = cls(self).difference(other)
+        diff2 = cls(other).difference(self)
+        return diff1.union(diff2)
+
+    def _update_items(self, items):
+        """
+        Replace the 'items' list of this OrderedSet with a new one, updating
+        self.map accordingly.
+        """
+        self.items = items
+        self.map = {item: idx for (idx, item) in enumerate(items)}
+
+    def difference_update(self, *sets):
+        """
+        Update this OrderedSet to remove items from one or more other sets.
+
+        Example:
+            >>> this = OrderedSet([1, 2, 3])
+            >>> this.difference_update(OrderedSet([2, 4]))
+            >>> print(this)
+            OrderedSet([1, 3])
+
+            >>> this = OrderedSet([1, 2, 3, 4, 5])
+            >>> this.difference_update(OrderedSet([2, 4]), OrderedSet([1, 4, 6]))
+            >>> print(this)
+            OrderedSet([3, 5])
+        """
+        items_to_remove = set()
+        for other in sets:
+            items_to_remove |= set(other)
+        self._update_items([item for item in self.items if item not in items_to_remove])
+
+    def intersection_update(self, other):
+        """
+        Update this OrderedSet to keep only items in another set, preserving
+        their order in this set.
+
+        Example:
+            >>> this = OrderedSet([1, 4, 3, 5, 7])
+            >>> other = OrderedSet([9, 7, 1, 3, 2])
+            >>> this.intersection_update(other)
+            >>> print(this)
+            OrderedSet([1, 3, 7])
+        """
+        other = set(other)
+        self._update_items([item for item in self.items if item in other])
+
+    def symmetric_difference_update(self, other):
+        """
+        Update this OrderedSet to remove items from another set, then
+        add items from the other set that were not present in this set.
+
+        Example:
+            >>> this = OrderedSet([1, 4, 3, 5, 7])
+            >>> other = OrderedSet([9, 7, 1, 3, 2])
+            >>> this.symmetric_difference_update(other)
+            >>> print(this)
+            OrderedSet([4, 5, 9, 2])
+        """
+        items_to_add = [item for item in other if item not in self]
+        items_to_remove = set(other)
+        self._update_items(
+            [item for item in self.items if item not in items_to_remove] + items_to_add
+        )
diff --git a/setuptools/_vendor/packaging/__about__.py b/setuptools/_vendor/packaging/__about__.py
index 95d330ef..dc95138d 100644
--- a/setuptools/_vendor/packaging/__about__.py
+++ b/setuptools/_vendor/packaging/__about__.py
@@ -4,18 +4,24 @@
 from __future__ import absolute_import, division, print_function
 
 __all__ = [
-    "__title__", "__summary__", "__uri__", "__version__", "__author__",
-    "__email__", "__license__", "__copyright__",
+    "__title__",
+    "__summary__",
+    "__uri__",
+    "__version__",
+    "__author__",
+    "__email__",
+    "__license__",
+    "__copyright__",
 ]
 
 __title__ = "packaging"
 __summary__ = "Core utilities for Python packages"
 __uri__ = "https://github.com/pypa/packaging"
 
-__version__ = "16.8"
+__version__ = "19.2"
 
 __author__ = "Donald Stufft and individual contributors"
 __email__ = "donald@stufft.io"
 
 __license__ = "BSD or Apache License, Version 2.0"
-__copyright__ = "Copyright 2014-2016 %s" % __author__
+__copyright__ = "Copyright 2014-2019 %s" % __author__
diff --git a/setuptools/_vendor/packaging/__init__.py b/setuptools/_vendor/packaging/__init__.py
index 5ee62202..a0cf67df 100644
--- a/setuptools/_vendor/packaging/__init__.py
+++ b/setuptools/_vendor/packaging/__init__.py
@@ -4,11 +4,23 @@
 from __future__ import absolute_import, division, print_function
 
 from .__about__ import (
-    __author__, __copyright__, __email__, __license__, __summary__, __title__,
-    __uri__, __version__
+    __author__,
+    __copyright__,
+    __email__,
+    __license__,
+    __summary__,
+    __title__,
+    __uri__,
+    __version__,
 )
 
 __all__ = [
-    "__title__", "__summary__", "__uri__", "__version__", "__author__",
-    "__email__", "__license__", "__copyright__",
+    "__title__",
+    "__summary__",
+    "__uri__",
+    "__version__",
+    "__author__",
+    "__email__",
+    "__license__",
+    "__copyright__",
 ]
diff --git a/setuptools/_vendor/packaging/_compat.py b/setuptools/_vendor/packaging/_compat.py
index 210bb80b..25da473c 100644
--- a/setuptools/_vendor/packaging/_compat.py
+++ b/setuptools/_vendor/packaging/_compat.py
@@ -12,9 +12,9 @@ PY3 = sys.version_info[0] == 3
 # flake8: noqa
 
 if PY3:
-    string_types = str,
+    string_types = (str,)
 else:
-    string_types = basestring,
+    string_types = (basestring,)
 
 
 def with_metaclass(meta, *bases):
@@ -27,4 +27,5 @@ def with_metaclass(meta, *bases):
     class metaclass(meta):
         def __new__(cls, name, this_bases, d):
             return meta(name, bases, d)
-    return type.__new__(metaclass, 'temporary_class', (), {})
+
+    return type.__new__(metaclass, "temporary_class", (), {})
diff --git a/setuptools/_vendor/packaging/_structures.py b/setuptools/_vendor/packaging/_structures.py
index ccc27861..68dcca63 100644
--- a/setuptools/_vendor/packaging/_structures.py
+++ b/setuptools/_vendor/packaging/_structures.py
@@ -5,7 +5,6 @@ from __future__ import absolute_import, division, print_function
 
 
 class Infinity(object):
-
     def __repr__(self):
         return "Infinity"
 
@@ -33,11 +32,11 @@ class Infinity(object):
     def __neg__(self):
         return NegativeInfinity
 
+
 Infinity = Infinity()
 
 
 class NegativeInfinity(object):
-
     def __repr__(self):
         return "-Infinity"
 
@@ -65,4 +64,5 @@ class NegativeInfinity(object):
     def __neg__(self):
         return Infinity
 
+
 NegativeInfinity = NegativeInfinity()
diff --git a/setuptools/_vendor/packaging/markers.py b/setuptools/_vendor/packaging/markers.py
index 031332a3..4bdfdb24 100644
--- a/setuptools/_vendor/packaging/markers.py
+++ b/setuptools/_vendor/packaging/markers.py
@@ -17,8 +17,11 @@ from .specifiers import Specifier, InvalidSpecifier
 
 
 __all__ = [
-    "InvalidMarker", "UndefinedComparison", "UndefinedEnvironmentName",
-    "Marker", "default_environment",
+    "InvalidMarker",
+    "UndefinedComparison",
+    "UndefinedEnvironmentName",
+    "Marker",
+    "default_environment",
 ]
 
 
@@ -42,7 +45,6 @@ class UndefinedEnvironmentName(ValueError):
 
 
 class Node(object):
-
     def __init__(self, value):
         self.value = value
 
@@ -57,62 +59,52 @@ class Node(object):
 
 
 class Variable(Node):
-
     def serialize(self):
         return str(self)
 
 
 class Value(Node):
-
     def serialize(self):
         return '"{0}"'.format(self)
 
 
 class Op(Node):
-
     def serialize(self):
         return str(self)
 
 
 VARIABLE = (
-    L("implementation_version") |
-    L("platform_python_implementation") |
-    L("implementation_name") |
-    L("python_full_version") |
-    L("platform_release") |
-    L("platform_version") |
-    L("platform_machine") |
-    L("platform_system") |
-    L("python_version") |
-    L("sys_platform") |
-    L("os_name") |
-    L("os.name") |  # PEP-345
-    L("sys.platform") |  # PEP-345
-    L("platform.version") |  # PEP-345
-    L("platform.machine") |  # PEP-345
-    L("platform.python_implementation") |  # PEP-345
-    L("python_implementation") |  # undocumented setuptools legacy
-    L("extra")
+    L("implementation_version")
+    | L("platform_python_implementation")
+    | L("implementation_name")
+    | L("python_full_version")
+    | L("platform_release")
+    | L("platform_version")
+    | L("platform_machine")
+    | L("platform_system")
+    | L("python_version")
+    | L("sys_platform")
+    | L("os_name")
+    | L("os.name")
+    | L("sys.platform")  # PEP-345
+    | L("platform.version")  # PEP-345
+    | L("platform.machine")  # PEP-345
+    | L("platform.python_implementation")  # PEP-345
+    | L("python_implementation")  # PEP-345
+    | L("extra")  # undocumented setuptools legacy
 )
 ALIASES = {
-    'os.name': 'os_name',
-    'sys.platform': 'sys_platform',
-    'platform.version': 'platform_version',
-    'platform.machine': 'platform_machine',
-    'platform.python_implementation': 'platform_python_implementation',
-    'python_implementation': 'platform_python_implementation'
+    "os.name": "os_name",
+    "sys.platform": "sys_platform",
+    "platform.version": "platform_version",
+    "platform.machine": "platform_machine",
+    "platform.python_implementation": "platform_python_implementation",
+    "python_implementation": "platform_python_implementation",
 }
 VARIABLE.setParseAction(lambda s, l, t: Variable(ALIASES.get(t[0], t[0])))
 
 VERSION_CMP = (
-    L("===") |
-    L("==") |
-    L(">=") |
-    L("<=") |
-    L("!=") |
-    L("~=") |
-    L(">") |
-    L("<")
+    L("===") | L("==") | L(">=") | L("<=") | L("!=") | L("~=") | L(">") | L("<")
 )
 
 MARKER_OP = VERSION_CMP | L("not in") | L("in")
@@ -152,8 +144,11 @@ def _format_marker(marker, first=True):
     # where the single item is itself it's own list. In that case we want skip
     # the rest of this function so that we don't get extraneous () on the
     # outside.
-    if (isinstance(marker, list) and len(marker) == 1 and
-            isinstance(marker[0], (list, tuple))):
+    if (
+        isinstance(marker, list)
+        and len(marker) == 1
+        and isinstance(marker[0], (list, tuple))
+    ):
         return _format_marker(marker[0])
 
     if isinstance(marker, list):
@@ -239,20 +234,20 @@ def _evaluate_markers(markers, environment):
 
 
 def format_full_version(info):
-    version = '{0.major}.{0.minor}.{0.micro}'.format(info)
+    version = "{0.major}.{0.minor}.{0.micro}".format(info)
     kind = info.releaselevel
-    if kind != 'final':
+    if kind != "final":
         version += kind[0] + str(info.serial)
     return version
 
 
 def default_environment():
-    if hasattr(sys, 'implementation'):
+    if hasattr(sys, "implementation"):
         iver = format_full_version(sys.implementation.version)
         implementation_name = sys.implementation.name
     else:
-        iver = '0'
-        implementation_name = ''
+        iver = "0"
+        implementation_name = ""
 
     return {
         "implementation_name": implementation_name,
@@ -264,19 +259,19 @@ def default_environment():
         "platform_version": platform.version(),
         "python_full_version": platform.python_version(),
         "platform_python_implementation": platform.python_implementation(),
-        "python_version": platform.python_version()[:3],
+        "python_version": ".".join(platform.python_version_tuple()[:2]),
         "sys_platform": sys.platform,
     }
 
 
 class Marker(object):
-
     def __init__(self, marker):
         try:
             self._markers = _coerce_parse_result(MARKER.parseString(marker))
         except ParseException as e:
             err_str = "Invalid marker: {0!r}, parse error at {1!r}".format(
-                marker, marker[e.loc:e.loc + 8])
+                marker, marker[e.loc : e.loc + 8]
+            )
             raise InvalidMarker(err_str)
 
     def __str__(self):
diff --git a/setuptools/_vendor/packaging/requirements.py b/setuptools/_vendor/packaging/requirements.py
index 5b493416..8a0c2cb9 100644
--- a/setuptools/_vendor/packaging/requirements.py
+++ b/setuptools/_vendor/packaging/requirements.py
@@ -38,8 +38,8 @@ IDENTIFIER = Combine(ALPHANUM + ZeroOrMore(IDENTIFIER_END))
 NAME = IDENTIFIER("name")
 EXTRA = IDENTIFIER
 
-URI = Regex(r'[^ ]+')("url")
-URL = (AT + URI)
+URI = Regex(r"[^ ]+")("url")
+URL = AT + URI
 
 EXTRAS_LIST = EXTRA + ZeroOrMore(COMMA + EXTRA)
 EXTRAS = (LBRACKET + Optional(EXTRAS_LIST) + RBRACKET)("extras")
@@ -48,28 +48,31 @@ VERSION_PEP440 = Regex(Specifier._regex_str, re.VERBOSE | re.IGNORECASE)
 VERSION_LEGACY = Regex(LegacySpecifier._regex_str, re.VERBOSE | re.IGNORECASE)
 
 VERSION_ONE = VERSION_PEP440 ^ VERSION_LEGACY
-VERSION_MANY = Combine(VERSION_ONE + ZeroOrMore(COMMA + VERSION_ONE),
-                       joinString=",", adjacent=False)("_raw_spec")
+VERSION_MANY = Combine(
+    VERSION_ONE + ZeroOrMore(COMMA + VERSION_ONE), joinString=",", adjacent=False
+)("_raw_spec")
 _VERSION_SPEC = Optional(((LPAREN + VERSION_MANY + RPAREN) | VERSION_MANY))
-_VERSION_SPEC.setParseAction(lambda s, l, t: t._raw_spec or '')
+_VERSION_SPEC.setParseAction(lambda s, l, t: t._raw_spec or "")
 
 VERSION_SPEC = originalTextFor(_VERSION_SPEC)("specifier")
 VERSION_SPEC.setParseAction(lambda s, l, t: t[1])
 
 MARKER_EXPR = originalTextFor(MARKER_EXPR())("marker")
 MARKER_EXPR.setParseAction(
-    lambda s, l, t: Marker(s[t._original_start:t._original_end])
+    lambda s, l, t: Marker(s[t._original_start : t._original_end])
 )
-MARKER_SEPERATOR = SEMICOLON
-MARKER = MARKER_SEPERATOR + MARKER_EXPR
+MARKER_SEPARATOR = SEMICOLON
+MARKER = MARKER_SEPARATOR + MARKER_EXPR
 
 VERSION_AND_MARKER = VERSION_SPEC + Optional(MARKER)
 URL_AND_MARKER = URL + Optional(MARKER)
 
-NAMED_REQUIREMENT = \
-    NAME + Optional(EXTRAS) + (URL_AND_MARKER | VERSION_AND_MARKER)
+NAMED_REQUIREMENT = NAME + Optional(EXTRAS) + (URL_AND_MARKER | VERSION_AND_MARKER)
 
 REQUIREMENT = stringStart + NAMED_REQUIREMENT + stringEnd
+# setuptools.extern.pyparsing isn't thread safe during initialization, so we do it eagerly, see
+# issue #104
+REQUIREMENT.parseString("x[]")
 
 
 class Requirement(object):
@@ -90,15 +93,21 @@ class Requirement(object):
             req = REQUIREMENT.parseString(requirement_string)
         except ParseException as e:
             raise InvalidRequirement(
-                "Invalid requirement, parse error at \"{0!r}\"".format(
-                    requirement_string[e.loc:e.loc + 8]))
+                'Parse error at "{0!r}": {1}'.format(
+                    requirement_string[e.loc : e.loc + 8], e.msg
+                )
+            )
 
         self.name = req.name
         if req.url:
             parsed_url = urlparse.urlparse(req.url)
-            if not (parsed_url.scheme and parsed_url.netloc) or (
-                    not parsed_url.scheme and not parsed_url.netloc):
-                raise InvalidRequirement("Invalid URL given")
+            if parsed_url.scheme == "file":
+                if urlparse.urlunparse(parsed_url) != req.url:
+                    raise InvalidRequirement("Invalid URL given")
+            elif not (parsed_url.scheme and parsed_url.netloc) or (
+                not parsed_url.scheme and not parsed_url.netloc
+            ):
+                raise InvalidRequirement("Invalid URL: {0}".format(req.url))
             self.url = req.url
         else:
             self.url = None
@@ -117,6 +126,8 @@ class Requirement(object):
 
         if self.url:
             parts.append("@ {0}".format(self.url))
+            if self.marker:
+                parts.append(" ")
 
         if self.marker:
             parts.append("; {0}".format(self.marker))
diff --git a/setuptools/_vendor/packaging/specifiers.py b/setuptools/_vendor/packaging/specifiers.py
index 7f5a76cf..743576a0 100644
--- a/setuptools/_vendor/packaging/specifiers.py
+++ b/setuptools/_vendor/packaging/specifiers.py
@@ -19,7 +19,6 @@ class InvalidSpecifier(ValueError):
 
 
 class BaseSpecifier(with_metaclass(abc.ABCMeta, object)):
-
     @abc.abstractmethod
     def __str__(self):
         """
@@ -84,10 +83,7 @@ class _IndividualSpecifier(BaseSpecifier):
         if not match:
             raise InvalidSpecifier("Invalid specifier: '{0}'".format(spec))
 
-        self._spec = (
-            match.group("operator").strip(),
-            match.group("version").strip(),
-        )
+        self._spec = (match.group("operator").strip(), match.group("version").strip())
 
         # Store whether or not this Specifier should accept prereleases
         self._prereleases = prereleases
@@ -99,11 +95,7 @@ class _IndividualSpecifier(BaseSpecifier):
             else ""
         )
 
-        return "<{0}({1!r}{2})>".format(
-            self.__class__.__name__,
-            str(self),
-            pre,
-        )
+        return "<{0}({1!r}{2})>".format(self.__class__.__name__, str(self), pre)
 
     def __str__(self):
         return "{0}{1}".format(*self._spec)
@@ -194,11 +186,12 @@ class _IndividualSpecifier(BaseSpecifier):
                 # If our version is a prerelease, and we were not set to allow
                 # prereleases, then we'll store it for later incase nothing
                 # else matches this specifier.
-                if (parsed_version.is_prerelease and not
-                        (prereleases or self.prereleases)):
+                if parsed_version.is_prerelease and not (
+                    prereleases or self.prereleases
+                ):
                     found_prereleases.append(version)
                 # Either this is not a prerelease, or we should have been
-                # accepting prereleases from the begining.
+                # accepting prereleases from the beginning.
                 else:
                     yielded = True
                     yield version
@@ -213,8 +206,7 @@ class _IndividualSpecifier(BaseSpecifier):
 
 class LegacySpecifier(_IndividualSpecifier):
 
-    _regex_str = (
-        r"""
+    _regex_str = r"""
         (?P<operator>(==|!=|<=|>=|<|>))
         \s*
         (?P<version>
@@ -225,10 +217,8 @@ class LegacySpecifier(_IndividualSpecifier):
                       # them, and a comma since it's a version separator.
         )
         """
-    )
 
-    _regex = re.compile(
-        r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+    _regex = re.compile(r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
 
     _operators = {
         "==": "equal",
@@ -269,13 +259,13 @@ def _require_version_compare(fn):
         if not isinstance(prospective, Version):
             return False
         return fn(self, prospective, spec)
+
     return wrapped
 
 
 class Specifier(_IndividualSpecifier):
 
-    _regex_str = (
-        r"""
+    _regex_str = r"""
         (?P<operator>(~=|==|!=|<=|>=|<|>|===))
         (?P<version>
             (?:
@@ -367,10 +357,8 @@ class Specifier(_IndividualSpecifier):
             )
         )
         """
-    )
 
-    _regex = re.compile(
-        r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+    _regex = re.compile(r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
 
     _operators = {
         "~=": "compatible",
@@ -397,8 +385,7 @@ class Specifier(_IndividualSpecifier):
         prefix = ".".join(
             list(
                 itertools.takewhile(
-                    lambda x: (not x.startswith("post") and not
-                               x.startswith("dev")),
+                    lambda x: (not x.startswith("post") and not x.startswith("dev")),
                     _version_split(spec),
                 )
             )[:-1]
@@ -407,8 +394,9 @@ class Specifier(_IndividualSpecifier):
         # Add the prefix notation to the end of our string
         prefix += ".*"
 
-        return (self._get_operator(">=")(prospective, spec) and
-                self._get_operator("==")(prospective, prefix))
+        return self._get_operator(">=")(prospective, spec) and self._get_operator("==")(
+            prospective, prefix
+        )
 
     @_require_version_compare
     def _compare_equal(self, prospective, spec):
@@ -428,7 +416,7 @@ class Specifier(_IndividualSpecifier):
             # Shorten the prospective version to be the same length as the spec
             # so that we can determine if the specifier is a prefix of the
             # prospective version or not.
-            prospective = prospective[:len(spec)]
+            prospective = prospective[: len(spec)]
 
             # Pad out our two sides with zeros so that they both equal the same
             # length.
@@ -503,7 +491,7 @@ class Specifier(_IndividualSpecifier):
                 return False
 
         # Ensure that we do not allow a local version of the version mentioned
-        # in the specifier, which is techincally greater than, to match.
+        # in the specifier, which is technically greater than, to match.
         if prospective.local is not None:
             if Version(prospective.base_version) == Version(spec.base_version):
                 return False
@@ -567,27 +555,17 @@ def _pad_version(left, right):
     right_split.append(list(itertools.takewhile(lambda x: x.isdigit(), right)))
 
     # Get the rest of our versions
-    left_split.append(left[len(left_split[0]):])
-    right_split.append(right[len(right_split[0]):])
+    left_split.append(left[len(left_split[0]) :])
+    right_split.append(right[len(right_split[0]) :])
 
     # Insert our padding
-    left_split.insert(
-        1,
-        ["0"] * max(0, len(right_split[0]) - len(left_split[0])),
-    )
-    right_split.insert(
-        1,
-        ["0"] * max(0, len(left_split[0]) - len(right_split[0])),
-    )
+    left_split.insert(1, ["0"] * max(0, len(right_split[0]) - len(left_split[0])))
+    right_split.insert(1, ["0"] * max(0, len(left_split[0]) - len(right_split[0])))
 
-    return (
-        list(itertools.chain(*left_split)),
-        list(itertools.chain(*right_split)),
-    )
+    return (list(itertools.chain(*left_split)), list(itertools.chain(*right_split)))
 
 
 class SpecifierSet(BaseSpecifier):
-
     def __init__(self, specifiers="", prereleases=None):
         # Split on , to break each indidivual specifier into it's own item, and
         # strip each item to remove leading/trailing whitespace.
@@ -721,10 +699,7 @@ class SpecifierSet(BaseSpecifier):
         # given version is contained within all of them.
         # Note: This use of all() here means that an empty set of specifiers
         #       will always return True, this is an explicit design decision.
-        return all(
-            s.contains(item, prereleases=prereleases)
-            for s in self._specs
-        )
+        return all(s.contains(item, prereleases=prereleases) for s in self._specs)
 
     def filter(self, iterable, prereleases=None):
         # Determine if we're forcing a prerelease or not, if we're not forcing
diff --git a/setuptools/_vendor/packaging/tags.py b/setuptools/_vendor/packaging/tags.py
new file mode 100644
index 00000000..ec9942f0
--- /dev/null
+++ b/setuptools/_vendor/packaging/tags.py
@@ -0,0 +1,404 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+from __future__ import absolute_import
+
+import distutils.util
+
+try:
+    from importlib.machinery import EXTENSION_SUFFIXES
+except ImportError:  # pragma: no cover
+    import imp
+
+    EXTENSION_SUFFIXES = [x[0] for x in imp.get_suffixes()]
+    del imp
+import platform
+import re
+import sys
+import sysconfig
+import warnings
+
+
+INTERPRETER_SHORT_NAMES = {
+    "python": "py",  # Generic.
+    "cpython": "cp",
+    "pypy": "pp",
+    "ironpython": "ip",
+    "jython": "jy",
+}
+
+
+_32_BIT_INTERPRETER = sys.maxsize <= 2 ** 32
+
+
+class Tag(object):
+
+    __slots__ = ["_interpreter", "_abi", "_platform"]
+
+    def __init__(self, interpreter, abi, platform):
+        self._interpreter = interpreter.lower()
+        self._abi = abi.lower()
+        self._platform = platform.lower()
+
+    @property
+    def interpreter(self):
+        return self._interpreter
+
+    @property
+    def abi(self):
+        return self._abi
+
+    @property
+    def platform(self):
+        return self._platform
+
+    def __eq__(self, other):
+        return (
+            (self.platform == other.platform)
+            and (self.abi == other.abi)
+            and (self.interpreter == other.interpreter)
+        )
+
+    def __hash__(self):
+        return hash((self._interpreter, self._abi, self._platform))
+
+    def __str__(self):
+        return "{}-{}-{}".format(self._interpreter, self._abi, self._platform)
+
+    def __repr__(self):
+        return "<{self} @ {self_id}>".format(self=self, self_id=id(self))
+
+
+def parse_tag(tag):
+    tags = set()
+    interpreters, abis, platforms = tag.split("-")
+    for interpreter in interpreters.split("."):
+        for abi in abis.split("."):
+            for platform_ in platforms.split("."):
+                tags.add(Tag(interpreter, abi, platform_))
+    return frozenset(tags)
+
+
+def _normalize_string(string):
+    return string.replace(".", "_").replace("-", "_")
+
+
+def _cpython_interpreter(py_version):
+    # TODO: Is using py_version_nodot for interpreter version critical?
+    return "cp{major}{minor}".format(major=py_version[0], minor=py_version[1])
+
+
+def _cpython_abis(py_version):
+    abis = []
+    version = "{}{}".format(*py_version[:2])
+    debug = pymalloc = ucs4 = ""
+    with_debug = sysconfig.get_config_var("Py_DEBUG")
+    has_refcount = hasattr(sys, "gettotalrefcount")
+    # Windows doesn't set Py_DEBUG, so checking for support of debug-compiled
+    # extension modules is the best option.
+    # https://github.com/pypa/pip/issues/3383#issuecomment-173267692
+    has_ext = "_d.pyd" in EXTENSION_SUFFIXES
+    if with_debug or (with_debug is None and (has_refcount or has_ext)):
+        debug = "d"
+    if py_version < (3, 8):
+        with_pymalloc = sysconfig.get_config_var("WITH_PYMALLOC")
+        if with_pymalloc or with_pymalloc is None:
+            pymalloc = "m"
+        if py_version < (3, 3):
+            unicode_size = sysconfig.get_config_var("Py_UNICODE_SIZE")
+            if unicode_size == 4 or (
+                unicode_size is None and sys.maxunicode == 0x10FFFF
+            ):
+                ucs4 = "u"
+    elif debug:
+        # Debug builds can also load "normal" extension modules.
+        # We can also assume no UCS-4 or pymalloc requirement.
+        abis.append("cp{version}".format(version=version))
+    abis.insert(
+        0,
+        "cp{version}{debug}{pymalloc}{ucs4}".format(
+            version=version, debug=debug, pymalloc=pymalloc, ucs4=ucs4
+        ),
+    )
+    return abis
+
+
+def _cpython_tags(py_version, interpreter, abis, platforms):
+    for abi in abis:
+        for platform_ in platforms:
+            yield Tag(interpreter, abi, platform_)
+    for tag in (Tag(interpreter, "abi3", platform_) for platform_ in platforms):
+        yield tag
+    for tag in (Tag(interpreter, "none", platform_) for platform_ in platforms):
+        yield tag
+    # PEP 384 was first implemented in Python 3.2.
+    for minor_version in range(py_version[1] - 1, 1, -1):
+        for platform_ in platforms:
+            interpreter = "cp{major}{minor}".format(
+                major=py_version[0], minor=minor_version
+            )
+            yield Tag(interpreter, "abi3", platform_)
+
+
+def _pypy_interpreter():
+    return "pp{py_major}{pypy_major}{pypy_minor}".format(
+        py_major=sys.version_info[0],
+        pypy_major=sys.pypy_version_info.major,
+        pypy_minor=sys.pypy_version_info.minor,
+    )
+
+
+def _generic_abi():
+    abi = sysconfig.get_config_var("SOABI")
+    if abi:
+        return _normalize_string(abi)
+    else:
+        return "none"
+
+
+def _pypy_tags(py_version, interpreter, abi, platforms):
+    for tag in (Tag(interpreter, abi, platform) for platform in platforms):
+        yield tag
+    for tag in (Tag(interpreter, "none", platform) for platform in platforms):
+        yield tag
+
+
+def _generic_tags(interpreter, py_version, abi, platforms):
+    for tag in (Tag(interpreter, abi, platform) for platform in platforms):
+        yield tag
+    if abi != "none":
+        tags = (Tag(interpreter, "none", platform_) for platform_ in platforms)
+        for tag in tags:
+            yield tag
+
+
+def _py_interpreter_range(py_version):
+    """
+    Yield Python versions in descending order.
+
+    After the latest version, the major-only version will be yielded, and then
+    all following versions up to 'end'.
+    """
+    yield "py{major}{minor}".format(major=py_version[0], minor=py_version[1])
+    yield "py{major}".format(major=py_version[0])
+    for minor in range(py_version[1] - 1, -1, -1):
+        yield "py{major}{minor}".format(major=py_version[0], minor=minor)
+
+
+def _independent_tags(interpreter, py_version, platforms):
+    """
+    Return the sequence of tags that are consistent across implementations.
+
+    The tags consist of:
+    - py*-none-<platform>
+    - <interpreter>-none-any
+    - py*-none-any
+    """
+    for version in _py_interpreter_range(py_version):
+        for platform_ in platforms:
+            yield Tag(version, "none", platform_)
+    yield Tag(interpreter, "none", "any")
+    for version in _py_interpreter_range(py_version):
+        yield Tag(version, "none", "any")
+
+
+def _mac_arch(arch, is_32bit=_32_BIT_INTERPRETER):
+    if not is_32bit:
+        return arch
+
+    if arch.startswith("ppc"):
+        return "ppc"
+
+    return "i386"
+
+
+def _mac_binary_formats(version, cpu_arch):
+    formats = [cpu_arch]
+    if cpu_arch == "x86_64":
+        if version < (10, 4):
+            return []
+        formats.extend(["intel", "fat64", "fat32"])
+
+    elif cpu_arch == "i386":
+        if version < (10, 4):
+            return []
+        formats.extend(["intel", "fat32", "fat"])
+
+    elif cpu_arch == "ppc64":
+        # TODO: Need to care about 32-bit PPC for ppc64 through 10.2?
+        if version > (10, 5) or version < (10, 4):
+            return []
+        formats.append("fat64")
+
+    elif cpu_arch == "ppc":
+        if version > (10, 6):
+            return []
+        formats.extend(["fat32", "fat"])
+
+    formats.append("universal")
+    return formats
+
+
+def _mac_platforms(version=None, arch=None):
+    version_str, _, cpu_arch = platform.mac_ver()
+    if version is None:
+        version = tuple(map(int, version_str.split(".")[:2]))
+    if arch is None:
+        arch = _mac_arch(cpu_arch)
+    platforms = []
+    for minor_version in range(version[1], -1, -1):
+        compat_version = version[0], minor_version
+        binary_formats = _mac_binary_formats(compat_version, arch)
+        for binary_format in binary_formats:
+            platforms.append(
+                "macosx_{major}_{minor}_{binary_format}".format(
+                    major=compat_version[0],
+                    minor=compat_version[1],
+                    binary_format=binary_format,
+                )
+            )
+    return platforms
+
+
+# From PEP 513.
+def _is_manylinux_compatible(name, glibc_version):
+    # Check for presence of _manylinux module.
+    try:
+        import _manylinux
+
+        return bool(getattr(_manylinux, name + "_compatible"))
+    except (ImportError, AttributeError):
+        # Fall through to heuristic check below.
+        pass
+
+    return _have_compatible_glibc(*glibc_version)
+
+
+def _glibc_version_string():
+    # Returns glibc version string, or None if not using glibc.
+    import ctypes
+
+    # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen
+    # manpage says, "If filename is NULL, then the returned handle is for the
+    # main program". This way we can let the linker do the work to figure out
+    # which libc our process is actually using.
+    process_namespace = ctypes.CDLL(None)
+    try:
+        gnu_get_libc_version = process_namespace.gnu_get_libc_version
+    except AttributeError:
+        # Symbol doesn't exist -> therefore, we are not linked to
+        # glibc.
+        return None
+
+    # Call gnu_get_libc_version, which returns a string like "2.5"
+    gnu_get_libc_version.restype = ctypes.c_char_p
+    version_str = gnu_get_libc_version()
+    # py2 / py3 compatibility:
+    if not isinstance(version_str, str):
+        version_str = version_str.decode("ascii")
+
+    return version_str
+
+
+# Separated out from have_compatible_glibc for easier unit testing.
+def _check_glibc_version(version_str, required_major, minimum_minor):
+    # Parse string and check against requested version.
+    #
+    # We use a regexp instead of str.split because we want to discard any
+    # random junk that might come after the minor version -- this might happen
+    # in patched/forked versions of glibc (e.g. Linaro's version of glibc
+    # uses version strings like "2.20-2014.11"). See gh-3588.
+    m = re.match(r"(?P<major>[0-9]+)\.(?P<minor>[0-9]+)", version_str)
+    if not m:
+        warnings.warn(
+            "Expected glibc version with 2 components major.minor,"
+            " got: %s" % version_str,
+            RuntimeWarning,
+        )
+        return False
+    return (
+        int(m.group("major")) == required_major
+        and int(m.group("minor")) >= minimum_minor
+    )
+
+
+def _have_compatible_glibc(required_major, minimum_minor):
+    version_str = _glibc_version_string()
+    if version_str is None:
+        return False
+    return _check_glibc_version(version_str, required_major, minimum_minor)
+
+
+def _linux_platforms(is_32bit=_32_BIT_INTERPRETER):
+    linux = _normalize_string(distutils.util.get_platform())
+    if linux == "linux_x86_64" and is_32bit:
+        linux = "linux_i686"
+    manylinux_support = (
+        ("manylinux2014", (2, 17)),  # CentOS 7 w/ glibc 2.17 (PEP 599)
+        ("manylinux2010", (2, 12)),  # CentOS 6 w/ glibc 2.12 (PEP 571)
+        ("manylinux1", (2, 5)),  # CentOS 5 w/ glibc 2.5 (PEP 513)
+    )
+    manylinux_support_iter = iter(manylinux_support)
+    for name, glibc_version in manylinux_support_iter:
+        if _is_manylinux_compatible(name, glibc_version):
+            platforms = [linux.replace("linux", name)]
+            break
+    else:
+        platforms = []
+    # Support for a later manylinux implies support for an earlier version.
+    platforms += [linux.replace("linux", name) for name, _ in manylinux_support_iter]
+    platforms.append(linux)
+    return platforms
+
+
+def _generic_platforms():
+    platform = _normalize_string(distutils.util.get_platform())
+    return [platform]
+
+
+def _interpreter_name():
+    name = platform.python_implementation().lower()
+    return INTERPRETER_SHORT_NAMES.get(name) or name
+
+
+def _generic_interpreter(name, py_version):
+    version = sysconfig.get_config_var("py_version_nodot")
+    if not version:
+        version = "".join(map(str, py_version[:2]))
+    return "{name}{version}".format(name=name, version=version)
+
+
+def sys_tags():
+    """
+    Returns the sequence of tag triples for the running interpreter.
+
+    The order of the sequence corresponds to priority order for the
+    interpreter, from most to least important.
+    """
+    py_version = sys.version_info[:2]
+    interpreter_name = _interpreter_name()
+    if platform.system() == "Darwin":
+        platforms = _mac_platforms()
+    elif platform.system() == "Linux":
+        platforms = _linux_platforms()
+    else:
+        platforms = _generic_platforms()
+
+    if interpreter_name == "cp":
+        interpreter = _cpython_interpreter(py_version)
+        abis = _cpython_abis(py_version)
+        for tag in _cpython_tags(py_version, interpreter, abis, platforms):
+            yield tag
+    elif interpreter_name == "pp":
+        interpreter = _pypy_interpreter()
+        abi = _generic_abi()
+        for tag in _pypy_tags(py_version, interpreter, abi, platforms):
+            yield tag
+    else:
+        interpreter = _generic_interpreter(interpreter_name, py_version)
+        abi = _generic_abi()
+        for tag in _generic_tags(interpreter, py_version, abi, platforms):
+            yield tag
+    for tag in _independent_tags(interpreter, py_version, platforms):
+        yield tag
diff --git a/setuptools/_vendor/packaging/utils.py b/setuptools/_vendor/packaging/utils.py
index 942387ce..88418786 100644
--- a/setuptools/_vendor/packaging/utils.py
+++ b/setuptools/_vendor/packaging/utils.py
@@ -5,6 +5,8 @@ from __future__ import absolute_import, division, print_function
 
 import re
 
+from .version import InvalidVersion, Version
+
 
 _canonicalize_regex = re.compile(r"[-_.]+")
 
@@ -12,3 +14,44 @@ _canonicalize_regex = re.compile(r"[-_.]+")
 def canonicalize_name(name):
     # This is taken from PEP 503.
     return _canonicalize_regex.sub("-", name).lower()
+
+
+def canonicalize_version(version):
+    """
+    This is very similar to Version.__str__, but has one subtle differences
+    with the way it handles the release segment.
+    """
+
+    try:
+        version = Version(version)
+    except InvalidVersion:
+        # Legacy versions cannot be normalized
+        return version
+
+    parts = []
+
+    # Epoch
+    if version.epoch != 0:
+        parts.append("{0}!".format(version.epoch))
+
+    # Release segment
+    # NB: This strips trailing '.0's to normalize
+    parts.append(re.sub(r"(\.0)+$", "", ".".join(str(x) for x in version.release)))
+
+    # Pre-release
+    if version.pre is not None:
+        parts.append("".join(str(x) for x in version.pre))
+
+    # Post-release
+    if version.post is not None:
+        parts.append(".post{0}".format(version.post))
+
+    # Development release
+    if version.dev is not None:
+        parts.append(".dev{0}".format(version.dev))
+
+    # Local version segment
+    if version.local is not None:
+        parts.append("+{0}".format(version.local))
+
+    return "".join(parts)
diff --git a/setuptools/_vendor/packaging/version.py b/setuptools/_vendor/packaging/version.py
index 83b5ee8c..95157a1f 100644
--- a/setuptools/_vendor/packaging/version.py
+++ b/setuptools/_vendor/packaging/version.py
@@ -10,14 +10,11 @@ import re
 from ._structures import Infinity
 
 
-__all__ = [
-    "parse", "Version", "LegacyVersion", "InvalidVersion", "VERSION_PATTERN"
-]
+__all__ = ["parse", "Version", "LegacyVersion", "InvalidVersion", "VERSION_PATTERN"]
 
 
 _Version = collections.namedtuple(
-    "_Version",
-    ["epoch", "release", "dev", "pre", "post", "local"],
+    "_Version", ["epoch", "release", "dev", "pre", "post", "local"]
 )
 
 
@@ -40,7 +37,6 @@ class InvalidVersion(ValueError):
 
 
 class _BaseVersion(object):
-
     def __hash__(self):
         return hash(self._key)
 
@@ -70,7 +66,6 @@ class _BaseVersion(object):
 
 
 class LegacyVersion(_BaseVersion):
-
     def __init__(self, version):
         self._version = str(version)
         self._key = _legacy_cmpkey(self._version)
@@ -90,6 +85,26 @@ class LegacyVersion(_BaseVersion):
         return self._version
 
     @property
+    def epoch(self):
+        return -1
+
+    @property
+    def release(self):
+        return None
+
+    @property
+    def pre(self):
+        return None
+
+    @property
+    def post(self):
+        return None
+
+    @property
+    def dev(self):
+        return None
+
+    @property
     def local(self):
         return None
 
@@ -101,13 +116,19 @@ class LegacyVersion(_BaseVersion):
     def is_postrelease(self):
         return False
 
+    @property
+    def is_devrelease(self):
+        return False
 
-_legacy_version_component_re = re.compile(
-    r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE,
-)
+
+_legacy_version_component_re = re.compile(r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE)
 
 _legacy_version_replacement_map = {
-    "pre": "c", "preview": "c", "-": "final-", "rc": "c", "dev": "@",
+    "pre": "c",
+    "preview": "c",
+    "-": "final-",
+    "rc": "c",
+    "dev": "@",
 }
 
 
@@ -154,6 +175,7 @@ def _legacy_cmpkey(version):
 
     return epoch, parts
 
+
 # Deliberately not anchored to the start and end of the string, to make it
 # easier for 3rd party code to reuse
 VERSION_PATTERN = r"""
@@ -190,10 +212,7 @@ VERSION_PATTERN = r"""
 
 class Version(_BaseVersion):
 
-    _regex = re.compile(
-        r"^\s*" + VERSION_PATTERN + r"\s*$",
-        re.VERBOSE | re.IGNORECASE,
-    )
+    _regex = re.compile(r"^\s*" + VERSION_PATTERN + r"\s*$", re.VERBOSE | re.IGNORECASE)
 
     def __init__(self, version):
         # Validate the version and parse it into pieces
@@ -205,18 +224,11 @@ class Version(_BaseVersion):
         self._version = _Version(
             epoch=int(match.group("epoch")) if match.group("epoch") else 0,
             release=tuple(int(i) for i in match.group("release").split(".")),
-            pre=_parse_letter_version(
-                match.group("pre_l"),
-                match.group("pre_n"),
-            ),
+            pre=_parse_letter_version(match.group("pre_l"), match.group("pre_n")),
             post=_parse_letter_version(
-                match.group("post_l"),
-                match.group("post_n1") or match.group("post_n2"),
-            ),
-            dev=_parse_letter_version(
-                match.group("dev_l"),
-                match.group("dev_n"),
+                match.group("post_l"), match.group("post_n1") or match.group("post_n2")
             ),
+            dev=_parse_letter_version(match.group("dev_l"), match.group("dev_n")),
             local=_parse_local_version(match.group("local")),
         )
 
@@ -237,33 +249,58 @@ class Version(_BaseVersion):
         parts = []
 
         # Epoch
-        if self._version.epoch != 0:
-            parts.append("{0}!".format(self._version.epoch))
+        if self.epoch != 0:
+            parts.append("{0}!".format(self.epoch))
 
         # Release segment
-        parts.append(".".join(str(x) for x in self._version.release))
+        parts.append(".".join(str(x) for x in self.release))
 
         # Pre-release
-        if self._version.pre is not None:
-            parts.append("".join(str(x) for x in self._version.pre))
+        if self.pre is not None:
+            parts.append("".join(str(x) for x in self.pre))
 
         # Post-release
-        if self._version.post is not None:
-            parts.append(".post{0}".format(self._version.post[1]))
+        if self.post is not None:
+            parts.append(".post{0}".format(self.post))
 
         # Development release
-        if self._version.dev is not None:
-            parts.append(".dev{0}".format(self._version.dev[1]))
+        if self.dev is not None:
+            parts.append(".dev{0}".format(self.dev))
 
         # Local version segment
-        if self._version.local is not None:
-            parts.append(
-                "+{0}".format(".".join(str(x) for x in self._version.local))
-            )
+        if self.local is not None:
+            parts.append("+{0}".format(self.local))
 
         return "".join(parts)
 
     @property
+    def epoch(self):
+        return self._version.epoch
+
+    @property
+    def release(self):
+        return self._version.release
+
+    @property
+    def pre(self):
+        return self._version.pre
+
+    @property
+    def post(self):
+        return self._version.post[1] if self._version.post else None
+
+    @property
+    def dev(self):
+        return self._version.dev[1] if self._version.dev else None
+
+    @property
+    def local(self):
+        if self._version.local:
+            return ".".join(str(x) for x in self._version.local)
+        else:
+            return None
+
+    @property
     def public(self):
         return str(self).split("+", 1)[0]
 
@@ -272,27 +309,25 @@ class Version(_BaseVersion):
         parts = []
 
         # Epoch
-        if self._version.epoch != 0:
-            parts.append("{0}!".format(self._version.epoch))
+        if self.epoch != 0:
+            parts.append("{0}!".format(self.epoch))
 
         # Release segment
-        parts.append(".".join(str(x) for x in self._version.release))
+        parts.append(".".join(str(x) for x in self.release))
 
         return "".join(parts)
 
     @property
-    def local(self):
-        version_string = str(self)
-        if "+" in version_string:
-            return version_string.split("+", 1)[1]
-
-    @property
     def is_prerelease(self):
-        return bool(self._version.dev or self._version.pre)
+        return self.dev is not None or self.pre is not None
 
     @property
     def is_postrelease(self):
-        return bool(self._version.post)
+        return self.post is not None
+
+    @property
+    def is_devrelease(self):
+        return self.dev is not None
 
 
 def _parse_letter_version(letter, number):
@@ -326,7 +361,7 @@ def _parse_letter_version(letter, number):
         return letter, int(number)
 
 
-_local_version_seperators = re.compile(r"[\._-]")
+_local_version_separators = re.compile(r"[\._-]")
 
 
 def _parse_local_version(local):
@@ -336,7 +371,7 @@ def _parse_local_version(local):
     if local is not None:
         return tuple(
             part.lower() if not part.isdigit() else int(part)
-            for part in _local_version_seperators.split(local)
+            for part in _local_version_separators.split(local)
         )
 
 
@@ -347,12 +382,7 @@ def _cmpkey(epoch, release, pre, post, dev, local):
     # re-reverse it back into the correct order and make it a tuple and use
     # that for our sorting key.
     release = tuple(
-        reversed(list(
-            itertools.dropwhile(
-                lambda x: x == 0,
-                reversed(release),
-            )
-        ))
+        reversed(list(itertools.dropwhile(lambda x: x == 0, reversed(release))))
     )
 
     # We need to "trick" the sorting algorithm to put 1.0.dev0 before 1.0a0.
@@ -385,9 +415,6 @@ def _cmpkey(epoch, release, pre, post, dev, local):
         # - Numeric segments sort numerically
         # - Shorter versions sort before longer versions when the prefixes
         #   match exactly
-        local = tuple(
-            (i, "") if isinstance(i, int) else (-Infinity, i)
-            for i in local
-        )
+        local = tuple((i, "") if isinstance(i, int) else (-Infinity, i) for i in local)
 
     return epoch, release, pre, post, dev, local
diff --git a/setuptools/_vendor/vendored.txt b/setuptools/_vendor/vendored.txt
index 7d77863d..65183d9a 100644
--- a/setuptools/_vendor/vendored.txt
+++ b/setuptools/_vendor/vendored.txt
@@ -1,3 +1,4 @@
-packaging==16.8
+packaging==19.2
 pyparsing==2.2.1
 six==1.10.0
+ordered-set==3.1.1
diff --git a/setuptools/archive_util.py b/setuptools/archive_util.py
index 81436044..64528ca7 100644
--- a/setuptools/archive_util.py
+++ b/setuptools/archive_util.py
@@ -25,7 +25,8 @@ def default_filter(src, dst):
     return dst
 
 
-def unpack_archive(filename, extract_dir, progress_filter=default_filter,
+def unpack_archive(
+        filename, extract_dir, progress_filter=default_filter,
         drivers=None):
     """Unpack `filename` to `extract_dir`, or raise ``UnrecognizedFormat``
 
@@ -148,7 +149,8 @@ def unpack_tarfile(filename, extract_dir, progress_filter=default_filter):
 
                 # resolve any links and to extract the link targets as normal
                 # files
-                while member is not None and (member.islnk() or member.issym()):
+                while member is not None and (
+                        member.islnk() or member.issym()):
                     linkpath = member.linkname
                     if member.issym():
                         base = posixpath.dirname(member.name)
diff --git a/setuptools/build_meta.py b/setuptools/build_meta.py
index 10c4b528..a1c951cf 100644
--- a/setuptools/build_meta.py
+++ b/setuptools/build_meta.py
@@ -48,6 +48,7 @@ __all__ = ['get_requires_for_build_sdist',
            '__legacy__',
            'SetupRequirementsError']
 
+
 class SetupRequirementsError(BaseException):
     def __init__(self, specifiers):
         self.specifiers = specifiers
@@ -143,7 +144,8 @@ class _BuildMetaBackend(object):
 
     def get_requires_for_build_wheel(self, config_settings=None):
         config_settings = self._fix_config(config_settings)
-        return self._get_build_requires(config_settings, requirements=['wheel'])
+        return self._get_build_requires(
+            config_settings, requirements=['wheel'])
 
     def get_requires_for_build_sdist(self, config_settings=None):
         config_settings = self._fix_config(config_settings)
@@ -160,8 +162,10 @@ class _BuildMetaBackend(object):
             dist_infos = [f for f in os.listdir(dist_info_directory)
                           if f.endswith('.dist-info')]
 
-            if (len(dist_infos) == 0 and
-                len(_get_immediate_subdirectories(dist_info_directory)) == 1):
+            if (
+                len(dist_infos) == 0 and
+                len(_get_immediate_subdirectories(dist_info_directory)) == 1
+            ):
 
                 dist_info_directory = os.path.join(
                     dist_info_directory, os.listdir(dist_info_directory)[0])
@@ -193,7 +197,8 @@ class _BuildMetaBackend(object):
                         config_settings["--global-option"])
             self.run_setup()
 
-            result_basename = _file_with_extension(tmp_dist_dir, result_extension)
+            result_basename = _file_with_extension(
+                tmp_dist_dir, result_extension)
             result_path = os.path.join(result_directory, result_basename)
             if os.path.exists(result_path):
                 # os.rename will fail overwriting on non-Unix.
@@ -202,7 +207,6 @@ class _BuildMetaBackend(object):
 
         return result_basename
 
-
     def build_wheel(self, wheel_directory, config_settings=None,
                     metadata_directory=None):
         return self._build_with_temp_dir(['bdist_wheel'], '.whl',
@@ -217,9 +221,12 @@ class _BuildMetaBackend(object):
 class _BuildMetaLegacyBackend(_BuildMetaBackend):
     """Compatibility backend for setuptools
 
-    This is a version of setuptools.build_meta that endeavors to maintain backwards
-    compatibility with pre-PEP 517 modes of invocation. It exists as a temporary
-    bridge between the old packaging mechanism and the new packaging mechanism,
+    This is a version of setuptools.build_meta that endeavors
+    to maintain backwards
+    compatibility with pre-PEP 517 modes of invocation. It
+    exists as a temporary
+    bridge between the old packaging mechanism and the new
+    packaging mechanism,
     and will eventually be removed.
     """
     def run_setup(self, setup_script='setup.py'):
@@ -232,6 +239,12 @@ class _BuildMetaLegacyBackend(_BuildMetaBackend):
         if script_dir not in sys.path:
             sys.path.insert(0, script_dir)
 
+        # Some setup.py scripts (e.g. in pygame and numpy) use sys.argv[0] to
+        # get the directory of the source code. They expect it to refer to the
+        # setup.py script.
+        sys_argv_0 = sys.argv[0]
+        sys.argv[0] = setup_script
+
         try:
             super(_BuildMetaLegacyBackend,
                   self).run_setup(setup_script=setup_script)
@@ -242,6 +255,8 @@ class _BuildMetaLegacyBackend(_BuildMetaBackend):
             # the original path so that the path manipulation does not persist
             # within the hook after run_setup is called.
             sys.path[:] = sys_path
+            sys.argv[0] = sys_argv_0
+
 
 # The primary backend
 _BACKEND = _BuildMetaBackend()
diff --git a/setuptools/command/__init__.py b/setuptools/command/__init__.py
index fe619e2e..743f5588 100644
--- a/setuptools/command/__init__.py
+++ b/setuptools/command/__init__.py
@@ -2,8 +2,7 @@ __all__ = [
     'alias', 'bdist_egg', 'bdist_rpm', 'build_ext', 'build_py', 'develop',
     'easy_install', 'egg_info', 'install', 'install_lib', 'rotate', 'saveopts',
     'sdist', 'setopt', 'test', 'install_egg_info', 'install_scripts',
-    'register', 'bdist_wininst', 'upload_docs', 'upload', 'build_clib',
-    'dist_info',
+    'bdist_wininst', 'upload_docs', 'build_clib', 'dist_info',
 ]
 
 from distutils.command.bdist import bdist
diff --git a/setuptools/command/bdist_egg.py b/setuptools/command/bdist_egg.py
index 9f8df917..1b28d4c9 100644
--- a/setuptools/command/bdist_egg.py
+++ b/setuptools/command/bdist_egg.py
@@ -11,13 +11,14 @@ import os
 import re
 import textwrap
 import marshal
+import warnings
 
 from setuptools.extern import six
 
 from pkg_resources import get_build_platform, Distribution, ensure_directory
 from pkg_resources import EntryPoint
 from setuptools.extension import Library
-from setuptools import Command
+from setuptools import Command, SetuptoolsDeprecationWarning
 
 try:
     # Python 2.7 or >=3.2
@@ -278,13 +279,19 @@ class bdist_egg(Command):
         if ep is None:
             return 'w'  # not an eggsecutable, do it the usual way.
 
+        warnings.warn(
+            "Eggsecutables are deprecated and will be removed in a future "
+            "version.",
+            SetuptoolsDeprecationWarning
+        )
+
         if not ep.attrs or ep.extras:
             raise DistutilsSetupError(
                 "eggsecutable entry point (%r) cannot have 'extras' "
                 "or refer to a module" % (ep,)
             )
 
-        pyver = sys.version[:3]
+        pyver = '{}.{}'.format(*sys.version_info)
         pkg = ep.module_name
         full = '.'.join(ep.attrs)
         base = ep.attrs[0]
diff --git a/setuptools/command/bdist_wininst.py b/setuptools/command/bdist_wininst.py
index 073de97b..ff4b6345 100644
--- a/setuptools/command/bdist_wininst.py
+++ b/setuptools/command/bdist_wininst.py
@@ -1,4 +1,7 @@
 import distutils.command.bdist_wininst as orig
+import warnings
+
+from setuptools import SetuptoolsDeprecationWarning
 
 
 class bdist_wininst(orig.bdist_wininst):
@@ -14,6 +17,12 @@ class bdist_wininst(orig.bdist_wininst):
         return cmd
 
     def run(self):
+        warnings.warn(
+            "bdist_wininst is deprecated and will be removed in a future "
+            "version. Use bdist_wheel (wheel packages) instead.",
+            SetuptoolsDeprecationWarning
+        )
+
         self._is_running = True
         try:
             orig.bdist_wininst.run(self)
diff --git a/setuptools/command/build_clib.py b/setuptools/command/build_clib.py
index 09caff6f..67ce2444 100644
--- a/setuptools/command/build_clib.py
+++ b/setuptools/command/build_clib.py
@@ -25,9 +25,9 @@ class build_clib(orig.build_clib):
             sources = build_info.get('sources')
             if sources is None or not isinstance(sources, (list, tuple)):
                 raise DistutilsSetupError(
-                       "in 'libraries' option (library '%s'), "
-                       "'sources' must be present and must be "
-                       "a list of source filenames" % lib_name)
+                    "in 'libraries' option (library '%s'), "
+                    "'sources' must be present and must be "
+                    "a list of source filenames" % lib_name)
             sources = list(sources)
 
             log.info("building '%s' library", lib_name)
@@ -38,9 +38,9 @@ class build_clib(orig.build_clib):
             obj_deps = build_info.get('obj_deps', dict())
             if not isinstance(obj_deps, dict):
                 raise DistutilsSetupError(
-                       "in 'libraries' option (library '%s'), "
-                       "'obj_deps' must be a dictionary of "
-                       "type 'source: list'" % lib_name)
+                    "in 'libraries' option (library '%s'), "
+                    "'obj_deps' must be a dictionary of "
+                    "type 'source: list'" % lib_name)
             dependencies = []
 
             # Get the global dependencies that are specified by the '' key.
@@ -48,9 +48,9 @@ class build_clib(orig.build_clib):
             global_deps = obj_deps.get('', list())
             if not isinstance(global_deps, (list, tuple)):
                 raise DistutilsSetupError(
-                       "in 'libraries' option (library '%s'), "
-                       "'obj_deps' must be a dictionary of "
-                       "type 'source: list'" % lib_name)
+                    "in 'libraries' option (library '%s'), "
+                    "'obj_deps' must be a dictionary of "
+                    "type 'source: list'" % lib_name)
 
             # Build the list to be used by newer_pairwise_group
             # each source will be auto-added to its dependencies.
@@ -60,39 +60,42 @@ class build_clib(orig.build_clib):
                 extra_deps = obj_deps.get(source, list())
                 if not isinstance(extra_deps, (list, tuple)):
                     raise DistutilsSetupError(
-                           "in 'libraries' option (library '%s'), "
-                           "'obj_deps' must be a dictionary of "
-                           "type 'source: list'" % lib_name)
+                        "in 'libraries' option (library '%s'), "
+                        "'obj_deps' must be a dictionary of "
+                        "type 'source: list'" % lib_name)
                 src_deps.extend(extra_deps)
                 dependencies.append(src_deps)
 
             expected_objects = self.compiler.object_filenames(
-                    sources,
-                    output_dir=self.build_temp
-                    )
+                sources,
+                output_dir=self.build_temp,
+            )
 
-            if newer_pairwise_group(dependencies, expected_objects) != ([], []):
+            if (
+                newer_pairwise_group(dependencies, expected_objects)
+                != ([], [])
+            ):
                 # First, compile the source code to object files in the library
                 # directory.  (This should probably change to putting object
                 # files in a temporary build directory.)
                 macros = build_info.get('macros')
                 include_dirs = build_info.get('include_dirs')
                 cflags = build_info.get('cflags')
-                objects = self.compiler.compile(
-                        sources,
-                        output_dir=self.build_temp,
-                        macros=macros,
-                        include_dirs=include_dirs,
-                        extra_postargs=cflags,
-                        debug=self.debug
-                        )
+                self.compiler.compile(
+                    sources,
+                    output_dir=self.build_temp,
+                    macros=macros,
+                    include_dirs=include_dirs,
+                    extra_postargs=cflags,
+                    debug=self.debug
+                )
 
             # Now "link" the object files together into a static library.
             # (On Unix at least, this isn't really linking -- it just
             # builds an archive.  Whatever.)
             self.compiler.create_static_lib(
-                    expected_objects,
-                    lib_name,
-                    output_dir=self.build_clib,
-                    debug=self.debug
-                    )
+                expected_objects,
+                lib_name,
+                output_dir=self.build_clib,
+                debug=self.debug
+            )
diff --git a/setuptools/command/build_ext.py b/setuptools/command/build_ext.py
index 60a8a32f..03b6f346 100644
--- a/setuptools/command/build_ext.py
+++ b/setuptools/command/build_ext.py
@@ -1,7 +1,6 @@
 import os
 import sys
 import itertools
-import imp
 from distutils.command.build_ext import build_ext as _du_build_ext
 from distutils.file_util import copy_file
 from distutils.ccompiler import new_compiler
@@ -12,6 +11,14 @@ from distutils import log
 from setuptools.extension import Library
 from setuptools.extern import six
 
+if six.PY2:
+    import imp
+
+    EXTENSION_SUFFIXES = [
+        s for s, _, tp in imp.get_suffixes() if tp == imp.C_EXTENSION]
+else:
+    from importlib.machinery import EXTENSION_SUFFIXES
+
 try:
     # Attempt to use Cython for building extensions, if available
     from Cython.Distutils.build_ext import build_ext as _build_ext
@@ -23,7 +30,7 @@ except ImportError:
 
 # make sure _config_vars is initialized
 get_config_var("LDSHARED")
-from distutils.sysconfig import _config_vars as _CONFIG_VARS
+from distutils.sysconfig import _config_vars as _CONFIG_VARS  # noqa
 
 
 def _customize_compiler_for_shlib(compiler):
@@ -59,12 +66,14 @@ elif os.name != 'nt':
     except ImportError:
         pass
 
-if_dl = lambda s: s if have_rtld else ''
+
+def if_dl(s):
+    return s if have_rtld else ''
 
 
 def get_abi3_suffix():
     """Return the file extension for an abi3-compliant Extension()"""
-    for suffix, _, _ in (s for s in imp.get_suffixes() if s[2] == imp.C_EXTENSION):
+    for suffix in EXTENSION_SUFFIXES:
         if '.abi3' in suffix:  # Unix
             return suffix
         elif suffix == '.pyd':  # Windows
@@ -107,7 +116,7 @@ class build_ext(_build_ext):
         if fullname in self.ext_map:
             ext = self.ext_map[fullname]
             use_abi3 = (
-                six.PY3
+                not six.PY2
                 and getattr(ext, 'py_limited_api')
                 and get_abi3_suffix()
             )
diff --git a/setuptools/command/build_py.py b/setuptools/command/build_py.py
index b0314fd4..9d0288a5 100644
--- a/setuptools/command/build_py.py
+++ b/setuptools/command/build_py.py
@@ -7,6 +7,7 @@ import textwrap
 import io
 import distutils.errors
 import itertools
+import stat
 
 from setuptools.extern import six
 from setuptools.extern.six.moves import map, filter, filterfalse
@@ -20,6 +21,10 @@ except ImportError:
             "do nothing"
 
 
+def make_writable(target):
+    os.chmod(target, os.stat(target).st_mode | stat.S_IWRITE)
+
+
 class build_py(orig.build_py, Mixin2to3):
     """Enhanced 'build_py' command that includes data files with packages
 
@@ -121,6 +126,7 @@ class build_py(orig.build_py, Mixin2to3):
                 self.mkpath(os.path.dirname(target))
                 srcfile = os.path.join(src_dir, filename)
                 outf, copied = self.copy_file(srcfile, target)
+                make_writable(target)
                 srcfile = os.path.abspath(srcfile)
                 if (copied and
                         srcfile in self.distribution.convert_2to3_doctests):
diff --git a/setuptools/command/develop.py b/setuptools/command/develop.py
index 009e4f93..b5619246 100644
--- a/setuptools/command/develop.py
+++ b/setuptools/command/develop.py
@@ -108,7 +108,7 @@ class develop(namespaces.DevelopInstaller, easy_install):
         return path_to_setup
 
     def install_for_development(self):
-        if six.PY3 and getattr(self.distribution, 'use_2to3', False):
+        if not six.PY2 and getattr(self.distribution, 'use_2to3', False):
             # If we run 2to3 we can not do this inplace:
 
             # Ensure metadata is up-to-date
diff --git a/setuptools/command/easy_install.py b/setuptools/command/easy_install.py
index 06c98271..5a9576ff 100644
--- a/setuptools/command/easy_install.py
+++ b/setuptools/command/easy_install.py
@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 """
 Easy Install
 ------------
@@ -121,7 +120,8 @@ else:
             return False
 
 
-_one_liner = lambda text: textwrap.dedent(text).strip().replace('\n', '; ')
+def _one_liner(text):
+    return textwrap.dedent(text).strip().replace('\n', '; ')
 
 
 class easy_install(Command):
@@ -156,19 +156,16 @@ class easy_install(Command):
          "allow building eggs from local checkouts"),
         ('version', None, "print version information and exit"),
         ('no-find-links', None,
-         "Don't load find-links defined in packages being installed")
+         "Don't load find-links defined in packages being installed"),
+        ('user', None, "install in user site-package '%s'" % site.USER_SITE)
     ]
     boolean_options = [
         'zip-ok', 'multi-version', 'exclude-scripts', 'upgrade', 'always-copy',
         'editable',
-        'no-deps', 'local-snapshots-ok', 'version'
+        'no-deps', 'local-snapshots-ok', 'version',
+        'user'
     ]
 
-    if site.ENABLE_USER_SITE:
-        help_msg = "install in user site-package '%s'" % site.USER_SITE
-        user_options.append(('user', None, help_msg))
-        boolean_options.append('user')
-
     negative_opt = {'always-unzip': 'zip-ok'}
     create_index = PackageIndex
 
@@ -241,7 +238,7 @@ class easy_install(Command):
         """
         Render the Setuptools version and installation details, then exit.
         """
-        ver = sys.version[:3]
+        ver = '{}.{}'.format(*sys.version_info)
         dist = get_distribution('setuptools')
         tmpl = 'setuptools {dist.version} from {dist.location} (Python {ver})'
         print(tmpl.format(**locals()))
@@ -272,6 +269,9 @@ class easy_install(Command):
             self.config_vars['userbase'] = self.install_userbase
             self.config_vars['usersite'] = self.install_usersite
 
+        elif self.user:
+            log.warn("WARNING: The user site-packages directory is disabled.")
+
         self._fix_install_dir_for_user_site()
 
         self.expand_basedirs()
@@ -410,7 +410,13 @@ class easy_install(Command):
         ]
         self._expand_attrs(dirs)
 
-    def run(self):
+    def run(self, show_deprecation=True):
+        if show_deprecation:
+            self.announce(
+                "WARNING: The easy_install command is deprecated "
+                "and will be removed in a future version.",
+                log.WARN,
+            )
         if self.verbose != self.distribution.verbose:
             log.set_verbosity(self.verbose)
         try:
@@ -453,6 +459,12 @@ class easy_install(Command):
         instdir = normalize_path(self.install_dir)
         pth_file = os.path.join(instdir, 'easy-install.pth')
 
+        if not os.path.exists(instdir):
+            try:
+                os.makedirs(instdir)
+            except (OSError, IOError):
+                self.cant_write_to_target()
+
         # Is it a configured, PYTHONPATH, implicit, or explicit site dir?
         is_site_dir = instdir in self.all_site_dirs
 
@@ -472,8 +484,9 @@ class easy_install(Command):
                 self.cant_write_to_target()
 
         if not is_site_dir and not self.multi_version:
-            # Can't install non-multi to non-site dir
-            raise DistutilsError(self.no_default_version_msg())
+            # Can't install non-multi to non-site dir with easy_install
+            pythonpath = os.environ.get('PYTHONPATH', '')
+            log.warn(self.__no_default_msg, self.install_dir, pythonpath)
 
         if is_site_dir:
             if self.pth_file is None:
@@ -501,13 +514,13 @@ class easy_install(Command):
         the distutils default setting) was:
 
             %s
-        """).lstrip()
+        """).lstrip()  # noqa
 
     __not_exists_id = textwrap.dedent("""
         This directory does not currently exist.  Please create it and try again, or
         choose a different installation directory (using the -d or --install-dir
         option).
-        """).lstrip()
+        """).lstrip()  # noqa
 
     __access_msg = textwrap.dedent("""
         Perhaps your account does not have write access to this directory?  If the
@@ -523,7 +536,7 @@ class easy_install(Command):
           https://setuptools.readthedocs.io/en/latest/easy_install.html
 
         Please make the appropriate changes for your system and try again.
-        """).lstrip()
+        """).lstrip()  # noqa
 
     def cant_write_to_target(self):
         msg = self.__cant_write_msg % (sys.exc_info()[1], self.install_dir,)
@@ -1087,13 +1100,13 @@ class easy_install(Command):
             pkg_resources.require("%(name)s")  # latest installed version
             pkg_resources.require("%(name)s==%(version)s")  # this exact version
             pkg_resources.require("%(name)s>=%(version)s")  # this version or higher
-        """).lstrip()
+        """).lstrip()  # noqa
 
     __id_warning = textwrap.dedent("""
         Note also that the installation directory must be on sys.path at runtime for
         this to work.  (e.g. by being the application's script directory, by being on
         PYTHONPATH, or by being added to sys.path by your code.)
-        """)
+        """)  # noqa
 
     def installation_report(self, req, dist, what="Installed"):
         """Helpful installation message for display to package users"""
@@ -1118,7 +1131,7 @@ class easy_install(Command):
             %(python)s setup.py develop
 
         See the setuptools documentation for the "develop" command for more info.
-        """).lstrip()
+        """).lstrip()  # noqa
 
     def report_editable(self, spec, setup_script):
         dirname = os.path.dirname(setup_script)
@@ -1180,8 +1193,7 @@ class easy_install(Command):
         # to the setup.cfg file.
         ei_opts = self.distribution.get_option_dict('easy_install').copy()
         fetch_directives = (
-            'find_links', 'site_dirs', 'index_url', 'optimize',
-            'site_dirs', 'allow_hosts',
+            'find_links', 'site_dirs', 'index_url', 'optimize', 'allow_hosts',
         )
         fetch_options = {}
         for key, val in ei_opts.items():
@@ -1302,11 +1314,8 @@ class easy_install(Command):
           https://setuptools.readthedocs.io/en/latest/easy_install.html#custom-installation-locations
 
 
-        Please make the appropriate changes for your system and try again.""").lstrip()
-
-    def no_default_version_msg(self):
-        template = self.__no_default_msg
-        return template % (self.install_dir, os.environ.get('PYTHONPATH', ''))
+        Please make the appropriate changes for your system and try again.
+        """).strip()
 
     def install_site_py(self):
         """Make sure there's a site.py in the target dir, if needed"""
@@ -1412,7 +1421,7 @@ def get_site_dirs():
                     os.path.join(
                         prefix,
                         "lib",
-                        "python" + sys.version[:3],
+                        "python{}.{}".format(*sys.version_info),
                         "site-packages",
                     ),
                     os.path.join(prefix, "lib", "site-python"),
@@ -1433,7 +1442,7 @@ def get_site_dirs():
                             home,
                             'Library',
                             'Python',
-                            sys.version[:3],
+                            '{}.{}'.format(*sys.version_info),
                             'site-packages',
                         )
                         sitedirs.append(home_sp)
@@ -1562,7 +1571,7 @@ def get_exe_prefixes(exe_filename):
                 continue
             if parts[0].upper() in ('PURELIB', 'PLATLIB'):
                 contents = z.read(name)
-                if six.PY3:
+                if not six.PY2:
                     contents = contents.decode()
                 for pth in yield_lines(contents):
                     pth = pth.strip().replace('\\', '/')
@@ -2088,7 +2097,8 @@ class ScriptWriter:
     @classmethod
     def get_script_header(cls, script_text, executable=None, wininst=False):
         # for backward compatibility
-        warnings.warn("Use get_header", EasyInstallDeprecationWarning, stacklevel=2)
+        warnings.warn(
+            "Use get_header", EasyInstallDeprecationWarning, stacklevel=2)
         if wininst:
             executable = "python.exe"
         return cls.get_header(script_text, executable)
@@ -2337,6 +2347,8 @@ def _patch_usage():
     finally:
         distutils.core.gen_usage = saved
 
+
 class EasyInstallDeprecationWarning(SetuptoolsDeprecationWarning):
-    """Class for warning about deprecations in EasyInstall in SetupTools. Not ignored by default, unlike DeprecationWarning."""
-    
+    """
+    Warning for EasyInstall deprecations, bypassing suppression.
+    """
diff --git a/setuptools/command/egg_info.py b/setuptools/command/egg_info.py
index 5d8f451e..7fa89541 100644
--- a/setuptools/command/egg_info.py
+++ b/setuptools/command/egg_info.py
@@ -33,6 +33,7 @@ from setuptools.glob import glob
 from setuptools.extern import packaging
 from setuptools import SetuptoolsDeprecationWarning
 
+
 def translate_pattern(glob):
     """
     Translate a file path glob like '*.txt' in to a regular expression.
@@ -113,7 +114,7 @@ def translate_pattern(glob):
             pat += sep
 
     pat += r'\Z'
-    return re.compile(pat, flags=re.MULTILINE|re.DOTALL)
+    return re.compile(pat, flags=re.MULTILINE | re.DOTALL)
 
 
 class InfoCommon:
@@ -266,7 +267,7 @@ class egg_info(InfoCommon, Command):
         to the file.
         """
         log.info("writing %s to %s", what, filename)
-        if six.PY3:
+        if not six.PY2:
             data = data.encode("utf-8")
         if not self.dry_run:
             f = open(filename, 'wb')
@@ -637,7 +638,9 @@ def warn_depends_obsolete(cmd, basename, filename):
 
 def _write_requirements(stream, reqs):
     lines = yield_lines(reqs or ())
-    append_cr = lambda line: line + '\n'
+
+    def append_cr(line):
+        return line + '\n'
     lines = map(append_cr, lines)
     stream.writelines(lines)
 
@@ -703,7 +706,8 @@ def get_pkg_info_revision():
     Get a -r### off of PKG-INFO Version in case this is an sdist of
     a subversion revision.
     """
-    warnings.warn("get_pkg_info_revision is deprecated.", EggInfoDeprecationWarning)
+    warnings.warn(
+        "get_pkg_info_revision is deprecated.", EggInfoDeprecationWarning)
     if os.path.exists('PKG-INFO'):
         with io.open('PKG-INFO') as f:
             for line in f:
@@ -714,4 +718,4 @@ def get_pkg_info_revision():
 
 
 class EggInfoDeprecationWarning(SetuptoolsDeprecationWarning):
-    """Class for warning about deprecations in eggInfo in setupTools. Not ignored by default, unlike DeprecationWarning."""
+    """Deprecated behavior warning for EggInfo, bypassing suppression."""
diff --git a/setuptools/command/install.py b/setuptools/command/install.py
index 31a5ddb5..72b9a3e4 100644
--- a/setuptools/command/install.py
+++ b/setuptools/command/install.py
@@ -114,7 +114,7 @@ class install(orig.install):
             args.insert(0, setuptools.bootstrap_install_from)
 
         cmd.args = args
-        cmd.run()
+        cmd.run(show_deprecation=False)
         setuptools.bootstrap_install_from = None
 
 
diff --git a/setuptools/command/install_lib.py b/setuptools/command/install_lib.py
index 2b31c3e3..2e9d8757 100644
--- a/setuptools/command/install_lib.py
+++ b/setuptools/command/install_lib.py
@@ -1,5 +1,5 @@
 import os
-import imp
+import sys
 from itertools import product, starmap
 import distutils.command.install_lib as orig
 
@@ -74,10 +74,11 @@ class install_lib(orig.install_lib):
         yield '__init__.pyc'
         yield '__init__.pyo'
 
-        if not hasattr(imp, 'get_tag'):
+        if not hasattr(sys, 'implementation'):
             return
 
-        base = os.path.join('__pycache__', '__init__.' + imp.get_tag())
+        base = os.path.join(
+            '__pycache__', '__init__.' + sys.implementation.cache_tag)
         yield base + '.pyc'
         yield base + '.pyo'
         yield base + '.opt-1.pyc'
diff --git a/setuptools/command/install_scripts.py b/setuptools/command/install_scripts.py
index 16234273..8c9a15e2 100644
--- a/setuptools/command/install_scripts.py
+++ b/setuptools/command/install_scripts.py
@@ -32,8 +32,11 @@ class install_scripts(orig.install_scripts):
         )
         bs_cmd = self.get_finalized_command('build_scripts')
         exec_param = getattr(bs_cmd, 'executable', None)
-        bw_cmd = self.get_finalized_command("bdist_wininst")
-        is_wininst = getattr(bw_cmd, '_is_running', False)
+        try:
+            bw_cmd = self.get_finalized_command("bdist_wininst")
+            is_wininst = getattr(bw_cmd, '_is_running', False)
+        except ImportError:
+            is_wininst = False
         writer = ei.ScriptWriter
         if is_wininst:
             exec_param = "python.exe"
diff --git a/setuptools/command/py36compat.py b/setuptools/command/py36compat.py
index 61063e75..28860558 100644
--- a/setuptools/command/py36compat.py
+++ b/setuptools/command/py36compat.py
@@ -132,5 +132,5 @@ class sdist_add_defaults:
 
 if hasattr(sdist.sdist, '_add_defaults_standards'):
     # disable the functionality already available upstream
-    class sdist_add_defaults:
+    class sdist_add_defaults:  # noqa
         pass
diff --git a/setuptools/command/register.py b/setuptools/command/register.py
index 98bc0156..b8266b9a 100644
--- a/setuptools/command/register.py
+++ b/setuptools/command/register.py
@@ -1,18 +1,18 @@
 from distutils import log
 import distutils.command.register as orig
 
+from setuptools.errors import RemovedCommandError
+
 
 class register(orig.register):
-    __doc__ = orig.register.__doc__
+    """Formerly used to register packages on PyPI."""
 
     def run(self):
-        try:
-            # Make sure that we are using valid current name/version info
-            self.run_command('egg_info')
-            orig.register.run(self)
-        finally:
-            self.announce(
-                "WARNING: Registering is deprecated, use twine to "
-                "upload instead (https://pypi.org/p/twine/)",
-                log.WARN
-            )
+        msg = (
+            "The register command has been removed, use twine to upload "
+            + "instead (https://pypi.org/p/twine)"
+        )
+
+        self.announce("ERROR: " + msg, log.ERROR)
+
+        raise RemovedCommandError(msg)
diff --git a/setuptools/command/sdist.py b/setuptools/command/sdist.py
index dc253981..8c3438ea 100644
--- a/setuptools/command/sdist.py
+++ b/setuptools/command/sdist.py
@@ -5,7 +5,7 @@ import sys
 import io
 import contextlib
 
-from setuptools.extern import six
+from setuptools.extern import six, ordered_set
 
 from .py36compat import sdist_add_defaults
 
@@ -121,19 +121,40 @@ class sdist(sdist_add_defaults, orig.sdist):
     if has_leaky_handle:
         read_template = __read_template_hack
 
+    def _add_defaults_optional(self):
+        if six.PY2:
+            sdist_add_defaults._add_defaults_optional(self)
+        else:
+            super()._add_defaults_optional()
+        if os.path.isfile('pyproject.toml'):
+            self.filelist.append('pyproject.toml')
+
     def _add_defaults_python(self):
         """getting python files"""
         if self.distribution.has_pure_modules():
             build_py = self.get_finalized_command('build_py')
             self.filelist.extend(build_py.get_source_files())
-            # This functionality is incompatible with include_package_data, and
-            # will in fact create an infinite recursion if include_package_data
-            # is True.  Use of include_package_data will imply that
-            # distutils-style automatic handling of package_data is disabled
-            if not self.distribution.include_package_data:
-                for _, src_dir, _, filenames in build_py.data_files:
-                    self.filelist.extend([os.path.join(src_dir, filename)
-                                          for filename in filenames])
+            self._add_data_files(self._safe_data_files(build_py))
+
+    def _safe_data_files(self, build_py):
+        """
+        Extracting data_files from build_py is known to cause
+        infinite recursion errors when `include_package_data`
+        is enabled, so suppress it in that case.
+        """
+        if self.distribution.include_package_data:
+            return ()
+        return build_py.data_files
+
+    def _add_data_files(self, data_files):
+        """
+        Add data files as found in build_py.data_files.
+        """
+        self.filelist.extend(
+            os.path.join(src_dir, name)
+            for _, src_dir, _, filenames in data_files
+            for name in filenames
+        )
 
     def _add_defaults_data_files(self):
         try:
@@ -186,7 +207,7 @@ class sdist(sdist_add_defaults, orig.sdist):
         manifest = open(self.manifest, 'rb')
         for line in manifest:
             # The manifest must contain UTF-8. See #303.
-            if six.PY3:
+            if not six.PY2:
                 try:
                     line = line.decode('UTF-8')
                 except UnicodeDecodeError:
@@ -200,10 +221,12 @@ class sdist(sdist_add_defaults, orig.sdist):
         manifest.close()
 
     def check_license(self):
-        """Checks if license_file' is configured and adds it to
-        'self.filelist' if the value contains a valid path.
+        """Checks if license_file' or 'license_files' is configured and adds any
+        valid paths to 'self.filelist'.
         """
 
+        files = ordered_set.OrderedSet()
+
         opts = self.distribution.get_option_dict('metadata')
 
         # ignore the source of the value
@@ -211,11 +234,19 @@ class sdist(sdist_add_defaults, orig.sdist):
 
         if license_file is None:
             log.debug("'license_file' option was not specified")
-            return
+        else:
+            files.add(license_file)
 
-        if not os.path.exists(license_file):
-            log.warn("warning: Failed to find the configured license file '%s'",
-                    license_file)
-            return
+        try:
+            files.update(self.distribution.metadata.license_files)
+        except TypeError:
+            log.warn("warning: 'license_files' option is malformed")
+
+        for f in files:
+            if not os.path.exists(f):
+                log.warn(
+                    "warning: Failed to find the configured license file '%s'",
+                    f)
+                files.remove(f)
 
-        self.filelist.append(license_file)
+        self.filelist.extend(files)
diff --git a/setuptools/command/test.py b/setuptools/command/test.py
index 973e4eb2..2d83967d 100644
--- a/setuptools/command/test.py
+++ b/setuptools/command/test.py
@@ -74,7 +74,7 @@ class NonDataProperty:
 class test(Command):
     """Command to run unit tests after in-place build"""
 
-    description = "run unit tests after in-place build"
+    description = "run unit tests after in-place build (deprecated)"
 
     user_options = [
         ('test-module=', 'm', "Run 'test_suite' in specified module"),
@@ -129,7 +129,8 @@ class test(Command):
 
     @contextlib.contextmanager
     def project_on_sys_path(self, include_dists=[]):
-        with_2to3 = six.PY3 and getattr(self.distribution, 'use_2to3', False)
+        with_2to3 = not six.PY2 and getattr(
+            self.distribution, 'use_2to3', False)
 
         if with_2to3:
             # If we run 2to3 we can not do this inplace:
@@ -214,6 +215,14 @@ class test(Command):
         return itertools.chain(ir_d, tr_d, er_d)
 
     def run(self):
+        self.announce(
+            "WARNING: Testing via this command is deprecated and will be "
+            "removed in a future version. Users looking for a generic test "
+            "entry point independent of test runner are encouraged to use "
+            "tox.",
+            log.WARN,
+        )
+
         installed_dists = self.install_dists(self.distribution)
 
         cmd = ' '.join(self._argv)
@@ -232,7 +241,7 @@ class test(Command):
         # Purge modules under test from sys.modules. The test loader will
         # re-import them from the build location. Required when 2to3 is used
         # with namespace packages.
-        if six.PY3 and getattr(self.distribution, 'use_2to3', False):
+        if not six.PY2 and getattr(self.distribution, 'use_2to3', False):
             module = self.test_suite.split('.')[0]
             if module in _namespace_packages:
                 del_modules = []
diff --git a/setuptools/command/upload.py b/setuptools/command/upload.py
index 6db8888b..ec7f81e2 100644
--- a/setuptools/command/upload.py
+++ b/setuptools/command/upload.py
@@ -1,196 +1,17 @@
-import io
-import os
-import hashlib
-import getpass
-
-from base64 import standard_b64encode
-
 from distutils import log
 from distutils.command import upload as orig
-from distutils.spawn import spawn
-
-from distutils.errors import DistutilsError
 
-from setuptools.extern.six.moves.urllib.request import urlopen, Request
-from setuptools.extern.six.moves.urllib.error import HTTPError
-from setuptools.extern.six.moves.urllib.parse import urlparse
+from setuptools.errors import RemovedCommandError
 
 
 class upload(orig.upload):
-    """
-    Override default upload behavior to obtain password
-    in a variety of different ways.
-    """
-    def run(self):
-        try:
-            orig.upload.run(self)
-        finally:
-            self.announce(
-                "WARNING: Uploading via this command is deprecated, use twine "
-                "to upload instead (https://pypi.org/p/twine/)",
-                log.WARN
-            )
+    """Formerly used to upload packages to PyPI."""
 
-    def finalize_options(self):
-        orig.upload.finalize_options(self)
-        self.username = (
-            self.username or
-            getpass.getuser()
-        )
-        # Attempt to obtain password. Short circuit evaluation at the first
-        # sign of success.
-        self.password = (
-            self.password or
-            self._load_password_from_keyring() or
-            self._prompt_for_password()
+    def run(self):
+        msg = (
+            "The upload command has been removed, use twine to upload "
+            + "instead (https://pypi.org/p/twine)"
         )
 
-    def upload_file(self, command, pyversion, filename):
-        # Makes sure the repository URL is compliant
-        schema, netloc, url, params, query, fragments = \
-            urlparse(self.repository)
-        if params or query or fragments:
-            raise AssertionError("Incompatible url %s" % self.repository)
-
-        if schema not in ('http', 'https'):
-            raise AssertionError("unsupported schema " + schema)
-
-        # Sign if requested
-        if self.sign:
-            gpg_args = ["gpg", "--detach-sign", "-a", filename]
-            if self.identity:
-                gpg_args[2:2] = ["--local-user", self.identity]
-            spawn(gpg_args,
-                  dry_run=self.dry_run)
-
-        # Fill in the data - send all the meta-data in case we need to
-        # register a new release
-        with open(filename, 'rb') as f:
-            content = f.read()
-
-        meta = self.distribution.metadata
-
-        data = {
-            # action
-            ':action': 'file_upload',
-            'protocol_version': '1',
-
-            # identify release
-            'name': meta.get_name(),
-            'version': meta.get_version(),
-
-            # file content
-            'content': (os.path.basename(filename), content),
-            'filetype': command,
-            'pyversion': pyversion,
-            'md5_digest': hashlib.md5(content).hexdigest(),
-
-            # additional meta-data
-            'metadata_version': str(meta.get_metadata_version()),
-            'summary': meta.get_description(),
-            'home_page': meta.get_url(),
-            'author': meta.get_contact(),
-            'author_email': meta.get_contact_email(),
-            'license': meta.get_licence(),
-            'description': meta.get_long_description(),
-            'keywords': meta.get_keywords(),
-            'platform': meta.get_platforms(),
-            'classifiers': meta.get_classifiers(),
-            'download_url': meta.get_download_url(),
-            # PEP 314
-            'provides': meta.get_provides(),
-            'requires': meta.get_requires(),
-            'obsoletes': meta.get_obsoletes(),
-            }
-
-        data['comment'] = ''
-
-        if self.sign:
-            data['gpg_signature'] = (os.path.basename(filename) + ".asc",
-                                     open(filename+".asc", "rb").read())
-
-        # set up the authentication
-        user_pass = (self.username + ":" + self.password).encode('ascii')
-        # The exact encoding of the authentication string is debated.
-        # Anyway PyPI only accepts ascii for both username or password.
-        auth = "Basic " + standard_b64encode(user_pass).decode('ascii')
-
-        # Build up the MIME payload for the POST data
-        boundary = '--------------GHSKFJDLGDS7543FJKLFHRE75642756743254'
-        sep_boundary = b'\r\n--' + boundary.encode('ascii')
-        end_boundary = sep_boundary + b'--\r\n'
-        body = io.BytesIO()
-        for key, value in data.items():
-            title = '\r\nContent-Disposition: form-data; name="%s"' % key
-            # handle multiple entries for the same name
-            if not isinstance(value, list):
-                value = [value]
-            for value in value:
-                if type(value) is tuple:
-                    title += '; filename="%s"' % value[0]
-                    value = value[1]
-                else:
-                    value = str(value).encode('utf-8')
-                body.write(sep_boundary)
-                body.write(title.encode('utf-8'))
-                body.write(b"\r\n\r\n")
-                body.write(value)
-        body.write(end_boundary)
-        body = body.getvalue()
-
-        msg = "Submitting %s to %s" % (filename, self.repository)
-        self.announce(msg, log.INFO)
-
-        # build the Request
-        headers = {
-            'Content-type': 'multipart/form-data; boundary=%s' % boundary,
-            'Content-length': str(len(body)),
-            'Authorization': auth,
-        }
-
-        request = Request(self.repository, data=body,
-                          headers=headers)
-        # send the data
-        try:
-            result = urlopen(request)
-            status = result.getcode()
-            reason = result.msg
-        except HTTPError as e:
-            status = e.code
-            reason = e.msg
-        except OSError as e:
-            self.announce(str(e), log.ERROR)
-            raise
-
-        if status == 200:
-            self.announce('Server response (%s): %s' % (status, reason),
-                          log.INFO)
-            if self.show_response:
-                text = getattr(self, '_read_pypi_response',
-                               lambda x: None)(result)
-                if text is not None:
-                    msg = '\n'.join(('-' * 75, text, '-' * 75))
-                    self.announce(msg, log.INFO)
-        else:
-            msg = 'Upload failed (%s): %s' % (status, reason)
-            self.announce(msg, log.ERROR)
-            raise DistutilsError(msg)
-
-    def _load_password_from_keyring(self):
-        """
-        Attempt to load password from keyring. Suppress Exceptions.
-        """
-        try:
-            keyring = __import__('keyring')
-            return keyring.get_password(self.repository, self.username)
-        except Exception:
-            pass
-
-    def _prompt_for_password(self):
-        """
-        Prompt for a password on the tty. Suppress Exceptions.
-        """
-        try:
-            return getpass.getpass()
-        except (Exception, KeyboardInterrupt):
-            pass
+        self.announce("ERROR: " + msg, log.ERROR)
+        raise RemovedCommandError(msg)
diff --git a/setuptools/command/upload_docs.py b/setuptools/command/upload_docs.py
index 07aa564a..0351da77 100644
--- a/setuptools/command/upload_docs.py
+++ b/setuptools/command/upload_docs.py
@@ -24,7 +24,7 @@ from .upload import upload
 
 
 def _encode(s):
-    errors = 'surrogateescape' if six.PY3 else 'strict'
+    errors = 'strict' if six.PY2 else 'surrogateescape'
     return s.encode('utf-8', errors)
 
 
@@ -127,8 +127,8 @@ class upload_docs(upload):
         """
         Build up the MIME payload for the POST data
         """
-        boundary = b'--------------GHSKFJDLGDS7543FJKLFHRE75642756743254'
-        sep_boundary = b'\n--' + boundary
+        boundary = '--------------GHSKFJDLGDS7543FJKLFHRE75642756743254'
+        sep_boundary = b'\n--' + boundary.encode('ascii')
         end_boundary = sep_boundary + b'--'
         end_items = end_boundary, b"\n",
         builder = functools.partial(
@@ -138,7 +138,7 @@ class upload_docs(upload):
         part_groups = map(builder, data.items())
         parts = itertools.chain.from_iterable(part_groups)
         body_items = itertools.chain(parts, end_items)
-        content_type = 'multipart/form-data; boundary=%s' % boundary.decode('ascii')
+        content_type = 'multipart/form-data; boundary=%s' % boundary
         return b''.join(body_items), content_type
 
     def upload_file(self, filename):
@@ -153,7 +153,7 @@ class upload_docs(upload):
         # set up the authentication
         credentials = _encode(self.username + ':' + self.password)
         credentials = standard_b64encode(credentials)
-        if six.PY3:
+        if not six.PY2:
             credentials = credentials.decode('ascii')
         auth = "Basic " + credentials
 
diff --git a/setuptools/config.py b/setuptools/config.py
index b6626043..45df2e3f 100644
--- a/setuptools/config.py
+++ b/setuptools/config.py
@@ -1,23 +1,64 @@
 from __future__ import absolute_import, unicode_literals
+import ast
 import io
 import os
 import sys
 
 import warnings
 import functools
+import importlib
 from collections import defaultdict
 from functools import partial
 from functools import wraps
-from importlib import import_module
+import contextlib
 
 from distutils.errors import DistutilsOptionError, DistutilsFileError
 from setuptools.extern.packaging.version import LegacyVersion, parse
+from setuptools.extern.packaging.specifiers import SpecifierSet
 from setuptools.extern.six import string_types, PY3
 
 
 __metaclass__ = type
 
 
+class StaticModule:
+    """
+    Attempt to load the module by the name
+    """
+    def __init__(self, name):
+        spec = importlib.util.find_spec(name)
+        with open(spec.origin) as strm:
+            src = strm.read()
+        module = ast.parse(src)
+        vars(self).update(locals())
+        del self.self
+
+    def __getattr__(self, attr):
+        try:
+            return next(
+                ast.literal_eval(statement.value)
+                for statement in self.module.body
+                if isinstance(statement, ast.Assign)
+                for target in statement.targets
+                if isinstance(target, ast.Name) and target.id == attr
+            )
+        except Exception:
+            raise AttributeError(
+                "{self.name} has no attribute {attr}".format(**locals()))
+
+
+@contextlib.contextmanager
+def patch_path(path):
+    """
+    Add path to front of sys.path for the duration of the context.
+    """
+    try:
+        sys.path.insert(0, path)
+        yield
+    finally:
+        sys.path.remove(path)
+
+
 def read_configuration(
         filepath, find_others=False, ignore_option_errors=False):
     """Read given configuration file and returns options from it as a dict.
@@ -343,15 +384,16 @@ class ConfigHandler:
             elif '' in package_dir:
                 # A custom parent directory was specified for all root modules
                 parent_path = os.path.join(os.getcwd(), package_dir[''])
-        sys.path.insert(0, parent_path)
-        try:
-            module = import_module(module_name)
-            value = getattr(module, attr_name)
 
-        finally:
-            sys.path = sys.path[1:]
+        with patch_path(parent_path):
+            try:
+                # attempt to load value statically
+                return getattr(StaticModule(module_name), attr_name)
+            except Exception:
+                # fallback to simple import
+                module = importlib.import_module(module_name)
 
-        return value
+        return getattr(module, attr_name)
 
     @classmethod
     def _get_parser_compound(cls, *parse_methods):
@@ -482,6 +524,7 @@ class ConfigMetadataHandler(ConfigHandler):
             'obsoletes': parse_list,
             'classifiers': self._get_parser_compound(parse_file, parse_list),
             'license': exclude_files_parser('license'),
+            'license_files': parse_list,
             'description': parse_file,
             'long_description': parse_file,
             'version': self._parse_version,
@@ -554,6 +597,7 @@ class ConfigOptionsHandler(ConfigHandler):
             'packages': self._parse_packages,
             'entry_points': self._parse_file,
             'py_modules': parse_list,
+            'python_requires': SpecifierSet,
         }
 
     def _parse_packages(self, value):
diff --git a/setuptools/dep_util.py b/setuptools/dep_util.py
index 2931c13e..521eb716 100644
--- a/setuptools/dep_util.py
+++ b/setuptools/dep_util.py
@@ -1,5 +1,6 @@
 from distutils.dep_util import newer_group
 
+
 # yes, this is was almost entirely copy-pasted from
 # 'newer_pairwise()', this is just another convenience
 # function.
@@ -10,7 +11,8 @@ def newer_pairwise_group(sources_groups, targets):
     of 'newer_group()'.
     """
     if len(sources_groups) != len(targets):
-        raise ValueError("'sources_group' and 'targets' must be the same length")
+        raise ValueError(
+            "'sources_group' and 'targets' must be the same length")
 
     # build a pair of lists (sources_groups, targets) where source is newer
     n_sources = []
diff --git a/setuptools/depends.py b/setuptools/depends.py
index 45e7052d..a37675cb 100644
--- a/setuptools/depends.py
+++ b/setuptools/depends.py
@@ -1,11 +1,13 @@
 import sys
-import imp
 import marshal
+import contextlib
 from distutils.version import StrictVersion
-from imp import PKG_DIRECTORY, PY_COMPILED, PY_SOURCE, PY_FROZEN
 
 from .py33compat import Bytecode
 
+from .py27compat import find_module, PY_COMPILED, PY_FROZEN, PY_SOURCE
+from . import py27compat
+
 
 __all__ = [
     'Require', 'find_module', 'get_module_constant', 'extract_constant'
@@ -15,7 +17,8 @@ __all__ = [
 class Require:
     """A prerequisite to building or installing a distribution"""
 
-    def __init__(self, name, requested_version, module, homepage='',
+    def __init__(
+            self, name, requested_version, module, homepage='',
             attribute=None, format=None):
 
         if format is None and requested_version is not None:
@@ -79,23 +82,15 @@ class Require:
         return self.version_ok(version)
 
 
-def find_module(module, paths=None):
-    """Just like 'imp.find_module()', but with package support"""
-
-    parts = module.split('.')
-
-    while parts:
-        part = parts.pop(0)
-        f, path, (suffix, mode, kind) = info = imp.find_module(part, paths)
-
-        if kind == PKG_DIRECTORY:
-            parts = parts or ['__init__']
-            paths = [path]
-
-        elif parts:
-            raise ImportError("Can't find %r in %s" % (parts, module))
+def maybe_close(f):
+    @contextlib.contextmanager
+    def empty():
+        yield
+        return
+    if not f:
+        return empty()
 
-    return info
+    return contextlib.closing(f)
 
 
 def get_module_constant(module, symbol, default=-1, paths=None):
@@ -106,28 +101,23 @@ def get_module_constant(module, symbol, default=-1, paths=None):
     constant.  Otherwise, return 'default'."""
 
     try:
-        f, path, (suffix, mode, kind) = find_module(module, paths)
+        f, path, (suffix, mode, kind) = info = find_module(module, paths)
     except ImportError:
         # Module doesn't exist
         return None
 
-    try:
+    with maybe_close(f):
         if kind == PY_COMPILED:
             f.read(8)  # skip magic & date
             code = marshal.load(f)
         elif kind == PY_FROZEN:
-            code = imp.get_frozen_object(module)
+            code = py27compat.get_frozen_object(module, paths)
         elif kind == PY_SOURCE:
             code = compile(f.read(), path, 'exec')
         else:
             # Not something we can parse; we'll have to import it.  :(
-            if module not in sys.modules:
-                imp.load_module(module, f, path, (suffix, mode, kind))
-            return getattr(sys.modules[module], symbol, None)
-
-    finally:
-        if f:
-            f.close()
+            imported = py27compat.get_module(module, paths, info)
+            return getattr(imported, symbol, None)
 
     return extract_constant(code, symbol, default)
 
diff --git a/setuptools/dist.py b/setuptools/dist.py
index ea6411b1..fe64afa9 100644
--- a/setuptools/dist.py
+++ b/setuptools/dist.py
@@ -19,19 +19,18 @@ import itertools
 from collections import defaultdict
 from email import message_from_file
 
-from distutils.errors import (
-    DistutilsOptionError, DistutilsPlatformError, DistutilsSetupError,
-)
+from distutils.errors import DistutilsOptionError, DistutilsSetupError
 from distutils.util import rfc822_escape
 from distutils.version import StrictVersion
 
 from setuptools.extern import six
 from setuptools.extern import packaging
+from setuptools.extern import ordered_set
 from setuptools.extern.six.moves import map, filter, filterfalse
 
 from . import SetuptoolsDeprecationWarning
 
-from setuptools.depends import Require
+import setuptools
 from setuptools import windows_support
 from setuptools.monkey import get_unpatched
 from setuptools.config import parse_configuration
@@ -161,7 +160,7 @@ def write_pkg_file(self, file):
     if self.download_url:
         write_field('Download-URL', self.download_url)
     for project_url in self.project_urls.items():
-        write_field('Project-URL',  '%s, %s' % project_url)
+        write_field('Project-URL', '%s, %s' % project_url)
 
     long_desc = rfc822_escape(self.get_long_description())
     write_field('Description', long_desc)
@@ -213,8 +212,12 @@ def check_importable(dist, attr, value):
 
 
 def assert_string_list(dist, attr, value):
-    """Verify that value is a string list or None"""
+    """Verify that value is a string list"""
     try:
+        # verify that value is a list or tuple to exclude unordered
+        # or single-use iterables
+        assert isinstance(value, (list, tuple))
+        # verify that elements of value are strings
         assert ''.join(value) != value
     except (TypeError, ValueError, AttributeError, AssertionError):
         raise DistutilsSetupError(
@@ -307,20 +310,17 @@ def check_test_suite(dist, attr, value):
 
 def check_package_data(dist, attr, value):
     """Verify that value is a dictionary of package names to glob lists"""
-    if isinstance(value, dict):
-        for k, v in value.items():
-            if not isinstance(k, str):
-                break
-            try:
-                iter(v)
-            except TypeError:
-                break
-        else:
-            return
-    raise DistutilsSetupError(
-        attr + " must be a dictionary mapping package names to lists of "
-        "wildcard patterns"
-    )
+    if not isinstance(value, dict):
+        raise DistutilsSetupError(
+            "{!r} must be a dictionary mapping package names to lists of "
+            "string wildcard patterns".format(attr))
+    for k, v in value.items():
+        if not isinstance(k, six.string_types):
+            raise DistutilsSetupError(
+                "keys of {!r} dict must be strings (got {!r})"
+                .format(attr, k)
+            )
+        assert_string_list(dist, 'values of {!r} dict'.format(attr), v)
 
 
 def check_packages(dist, attr, value):
@@ -336,7 +336,7 @@ _Distribution = get_unpatched(distutils.core.Distribution)
 
 
 class Distribution(_Distribution):
-    """Distribution with support for features, tests, and package data
+    """Distribution with support for tests and package data
 
     This is an enhanced version of 'distutils.dist.Distribution' that
     effectively adds the following new optional keyword arguments to 'setup()':
@@ -363,21 +363,6 @@ class Distribution(_Distribution):
         EasyInstall and requests one of your extras, the corresponding
         additional requirements will be installed if needed.
 
-     'features' **deprecated** -- a dictionary mapping option names to
-        'setuptools.Feature'
-        objects.  Features are a portion of the distribution that can be
-        included or excluded based on user options, inter-feature dependencies,
-        and availability on the current system.  Excluded features are omitted
-        from all setup commands, including source and binary distributions, so
-        you can create multiple distributions from the same source tree.
-        Feature names should be valid Python identifiers, except that they may
-        contain the '-' (minus) sign.  Features can be included or excluded
-        via the command line options '--with-X' and '--without-X', where 'X' is
-        the name of the feature.  Whether a feature is included by default, and
-        whether you are allowed to control this from the command line, is
-        determined by the Feature object.  See the 'Feature' class for more
-        information.
-
      'test_suite' -- the name of a test suite to run for the 'test' command.
         If the user runs 'python setup.py test', the package will be installed,
         and the named test suite will be run.  The format is the same as
@@ -399,14 +384,14 @@ class Distribution(_Distribution):
     for manipulating the distribution's contents.  For example, the 'include()'
     and 'exclude()' methods can be thought of as in-place add and subtract
     commands that add or remove packages, modules, extensions, and so on from
-    the distribution.  They are used by the feature subsystem to configure the
-    distribution for the included and excluded features.
+    the distribution.
     """
 
     _DISTUTILS_UNSUPPORTED_METADATA = {
         'long_description_content_type': None,
         'project_urls': dict,
-        'provides_extras': set,
+        'provides_extras': ordered_set.OrderedSet,
+        'license_files': ordered_set.OrderedSet,
     }
 
     _patched_dist = None
@@ -429,10 +414,6 @@ class Distribution(_Distribution):
         if not have_package_data:
             self.package_data = {}
         attrs = attrs or {}
-        if 'features' in attrs or 'require_features' in attrs:
-            Feature.warn_deprecated()
-        self.require_features = []
-        self.features = {}
         self.dist_files = []
         # Filter-out setuptools' specific options.
         self.src_root = attrs.pop("src_root", None)
@@ -458,30 +439,40 @@ class Distribution(_Distribution):
                 value = default() if default else None
             setattr(self.metadata, option, value)
 
-        if isinstance(self.metadata.version, numbers.Number):
+        self.metadata.version = self._normalize_version(
+            self._validate_version(self.metadata.version))
+        self._finalize_requires()
+
+    @staticmethod
+    def _normalize_version(version):
+        if isinstance(version, setuptools.sic) or version is None:
+            return version
+
+        normalized = str(packaging.version.Version(version))
+        if version != normalized:
+            tmpl = "Normalizing '{version}' to '{normalized}'"
+            warnings.warn(tmpl.format(**locals()))
+            return normalized
+        return version
+
+    @staticmethod
+    def _validate_version(version):
+        if isinstance(version, numbers.Number):
             # Some people apparently take "version number" too literally :)
-            self.metadata.version = str(self.metadata.version)
+            version = str(version)
 
-        if self.metadata.version is not None:
+        if version is not None:
             try:
-                ver = packaging.version.Version(self.metadata.version)
-                normalized_version = str(ver)
-                if self.metadata.version != normalized_version:
-                    warnings.warn(
-                        "Normalizing '%s' to '%s'" % (
-                            self.metadata.version,
-                            normalized_version,
-                        )
-                    )
-                    self.metadata.version = normalized_version
+                packaging.version.Version(version)
             except (packaging.version.InvalidVersion, TypeError):
                 warnings.warn(
                     "The version specified (%r) is an invalid version, this "
                     "may not work as expected with newer versions of "
                     "setuptools, pip, and PyPI. Please see PEP 440 for more "
-                    "details." % self.metadata.version
+                    "details." % version
                 )
-        self._finalize_requires()
+                return setuptools.sic(version)
+        return version
 
     def _finalize_requires(self):
         """
@@ -568,7 +559,7 @@ class Distribution(_Distribution):
         from setuptools.extern.six.moves.configparser import ConfigParser
 
         # Ignore install directory options if we have a venv
-        if six.PY3 and sys.prefix != sys.base_prefix:
+        if not six.PY2 and sys.prefix != sys.base_prefix:
             ignore_options = [
                 'install-base', 'install-platbase', 'install-lib',
                 'install-platlib', 'install-purelib', 'install-headers',
@@ -590,7 +581,7 @@ class Distribution(_Distribution):
             with io.open(filename, encoding='utf-8') as reader:
                 if DEBUG:
                     self.announce("  reading {filename}".format(**locals()))
-                (parser.read_file if six.PY3 else parser.readfp)(reader)
+                (parser.readfp if six.PY2 else parser.read_file)(reader)
             for section in parser.sections():
                 options = parser.options(section)
                 opt_dict = self.get_option_dict(section)
@@ -633,7 +624,7 @@ class Distribution(_Distribution):
 
         Ref #1653
         """
-        if six.PY3:
+        if not six.PY2:
             return val
         try:
             return val.encode()
@@ -699,17 +690,6 @@ class Distribution(_Distribution):
                             ignore_option_errors=ignore_option_errors)
         self._finalize_requires()
 
-    def parse_command_line(self):
-        """Process features after parsing command line options"""
-        result = _Distribution.parse_command_line(self)
-        if self.features:
-            self._finalize_features()
-        return result
-
-    def _feature_attrname(self, name):
-        """Convert feature name to corresponding option attribute name"""
-        return 'with_' + name.replace('-', '_')
-
     def fetch_build_eggs(self, requires):
         """Resolve pre-setup requirements"""
         resolved_dists = pkg_resources.working_set.resolve(
@@ -722,15 +702,28 @@ class Distribution(_Distribution):
         return resolved_dists
 
     def finalize_options(self):
-        _Distribution.finalize_options(self)
-        if self.features:
-            self._set_global_opts_from_features()
+        """
+        Allow plugins to apply arbitrary operations to the
+        distribution. Each hook may optionally define a 'order'
+        to influence the order of execution. Smaller numbers
+        go first and the default is 0.
+        """
+        group = 'setuptools.finalize_distribution_options'
 
+        def by_order(hook):
+            return getattr(hook, 'order', 0)
+        eps = map(lambda e: e.load(), pkg_resources.iter_entry_points(group))
+        for ep in sorted(eps, key=by_order):
+            ep(self)
+
+    def _finalize_setup_keywords(self):
         for ep in pkg_resources.iter_entry_points('distutils.setup_keywords'):
             value = getattr(self, ep.name, None)
             if value is not None:
                 ep.require(installer=self.fetch_build_egg)
                 ep.load()(self, ep.name, value)
+
+    def _finalize_2to3_doctests(self):
         if getattr(self, 'convert_2to3_doctests', None):
             # XXX may convert to set here when we can rely on set being builtin
             self.convert_2to3_doctests = [
@@ -757,76 +750,8 @@ class Distribution(_Distribution):
 
     def fetch_build_egg(self, req):
         """Fetch an egg needed for building"""
-        from setuptools.command.easy_install import easy_install
-        dist = self.__class__({'script_args': ['easy_install']})
-        opts = dist.get_option_dict('easy_install')
-        opts.clear()
-        opts.update(
-            (k, v)
-            for k, v in self.get_option_dict('easy_install').items()
-            if k in (
-                # don't use any other settings
-                'find_links', 'site_dirs', 'index_url',
-                'optimize', 'site_dirs', 'allow_hosts',
-            ))
-        if self.dependency_links:
-            links = self.dependency_links[:]
-            if 'find_links' in opts:
-                links = opts['find_links'][1] + links
-            opts['find_links'] = ('setup', links)
-        install_dir = self.get_egg_cache_dir()
-        cmd = easy_install(
-            dist, args=["x"], install_dir=install_dir,
-            exclude_scripts=True,
-            always_copy=False, build_directory=None, editable=False,
-            upgrade=False, multi_version=True, no_report=True, user=False
-        )
-        cmd.ensure_finalized()
-        return cmd.easy_install(req)
-
-    def _set_global_opts_from_features(self):
-        """Add --with-X/--without-X options based on optional features"""
-
-        go = []
-        no = self.negative_opt.copy()
-
-        for name, feature in self.features.items():
-            self._set_feature(name, None)
-            feature.validate(self)
-
-            if feature.optional:
-                descr = feature.description
-                incdef = ' (default)'
-                excdef = ''
-                if not feature.include_by_default():
-                    excdef, incdef = incdef, excdef
-
-                new = (
-                    ('with-' + name, None, 'include ' + descr + incdef),
-                    ('without-' + name, None, 'exclude ' + descr + excdef),
-                )
-                go.extend(new)
-                no['without-' + name] = 'with-' + name
-
-        self.global_options = self.feature_options = go + self.global_options
-        self.negative_opt = self.feature_negopt = no
-
-    def _finalize_features(self):
-        """Add/remove features and resolve dependencies between them"""
-
-        # First, flag all the enabled items (and thus their dependencies)
-        for name, feature in self.features.items():
-            enabled = self.feature_is_included(name)
-            if enabled or (enabled is None and feature.include_by_default()):
-                feature.include_in(self)
-                self._set_feature(name, 1)
-
-        # Then disable the rest, so that off-by-default features don't
-        # get flagged as errors when they're required by an enabled feature
-        for name, feature in self.features.items():
-            if not self.feature_is_included(name):
-                feature.exclude_from(self)
-                self._set_feature(name, 0)
+        from setuptools.installer import fetch_build_egg
+        return fetch_build_egg(self, req)
 
     def get_command_class(self, command):
         """Pluggable version of get_command_class()"""
@@ -857,25 +782,6 @@ class Distribution(_Distribution):
                 self.cmdclass[ep.name] = cmdclass
         return _Distribution.get_command_list(self)
 
-    def _set_feature(self, name, status):
-        """Set feature's inclusion status"""
-        setattr(self, self._feature_attrname(name), status)
-
-    def feature_is_included(self, name):
-        """Return 1 if feature is included, 0 if excluded, 'None' if unknown"""
-        return getattr(self, self._feature_attrname(name))
-
-    def include_feature(self, name):
-        """Request inclusion of feature named 'name'"""
-
-        if self.feature_is_included(name) == 0:
-            descr = self.features[name].description
-            raise DistutilsOptionError(
-                descr + " is required, but was excluded or is not available"
-            )
-        self.features[name].include_in(self)
-        self._set_feature(name, 1)
-
     def include(self, **attrs):
         """Add items to distribution that are named in keyword arguments
 
@@ -1120,160 +1026,6 @@ class Distribution(_Distribution):
                 sys.stdout.detach(), encoding, errors, newline, line_buffering)
 
 
-class Feature:
-    """
-    **deprecated** -- The `Feature` facility was never completely implemented
-    or supported, `has reported issues
-    <https://github.com/pypa/setuptools/issues/58>`_ and will be removed in
-    a future version.
-
-    A subset of the distribution that can be excluded if unneeded/wanted
-
-    Features are created using these keyword arguments:
-
-      'description' -- a short, human readable description of the feature, to
-         be used in error messages, and option help messages.
-
-      'standard' -- if true, the feature is included by default if it is
-         available on the current system.  Otherwise, the feature is only
-         included if requested via a command line '--with-X' option, or if
-         another included feature requires it.  The default setting is 'False'.
-
-      'available' -- if true, the feature is available for installation on the
-         current system.  The default setting is 'True'.
-
-      'optional' -- if true, the feature's inclusion can be controlled from the
-         command line, using the '--with-X' or '--without-X' options.  If
-         false, the feature's inclusion status is determined automatically,
-         based on 'availabile', 'standard', and whether any other feature
-         requires it.  The default setting is 'True'.
-
-      'require_features' -- a string or sequence of strings naming features
-         that should also be included if this feature is included.  Defaults to
-         empty list.  May also contain 'Require' objects that should be
-         added/removed from the distribution.
-
-      'remove' -- a string or list of strings naming packages to be removed
-         from the distribution if this feature is *not* included.  If the
-         feature *is* included, this argument is ignored.  This argument exists
-         to support removing features that "crosscut" a distribution, such as
-         defining a 'tests' feature that removes all the 'tests' subpackages
-         provided by other features.  The default for this argument is an empty
-         list.  (Note: the named package(s) or modules must exist in the base
-         distribution when the 'setup()' function is initially called.)
-
-      other keywords -- any other keyword arguments are saved, and passed to
-         the distribution's 'include()' and 'exclude()' methods when the
-         feature is included or excluded, respectively.  So, for example, you
-         could pass 'packages=["a","b"]' to cause packages 'a' and 'b' to be
-         added or removed from the distribution as appropriate.
-
-    A feature must include at least one 'requires', 'remove', or other
-    keyword argument.  Otherwise, it can't affect the distribution in any way.
-    Note also that you can subclass 'Feature' to create your own specialized
-    feature types that modify the distribution in other ways when included or
-    excluded.  See the docstrings for the various methods here for more detail.
-    Aside from the methods, the only feature attributes that distributions look
-    at are 'description' and 'optional'.
-    """
-
-    @staticmethod
-    def warn_deprecated():
-        msg = (
-            "Features are deprecated and will be removed in a future "
-            "version. See https://github.com/pypa/setuptools/issues/65."
-        )
-        warnings.warn(msg, DistDeprecationWarning, stacklevel=3)
-
-    def __init__(
-            self, description, standard=False, available=True,
-            optional=True, require_features=(), remove=(), **extras):
-        self.warn_deprecated()
-
-        self.description = description
-        self.standard = standard
-        self.available = available
-        self.optional = optional
-        if isinstance(require_features, (str, Require)):
-            require_features = require_features,
-
-        self.require_features = [
-            r for r in require_features if isinstance(r, str)
-        ]
-        er = [r for r in require_features if not isinstance(r, str)]
-        if er:
-            extras['require_features'] = er
-
-        if isinstance(remove, str):
-            remove = remove,
-        self.remove = remove
-        self.extras = extras
-
-        if not remove and not require_features and not extras:
-            raise DistutilsSetupError(
-                "Feature %s: must define 'require_features', 'remove', or "
-                "at least one of 'packages', 'py_modules', etc."
-            )
-
-    def include_by_default(self):
-        """Should this feature be included by default?"""
-        return self.available and self.standard
-
-    def include_in(self, dist):
-        """Ensure feature and its requirements are included in distribution
-
-        You may override this in a subclass to perform additional operations on
-        the distribution.  Note that this method may be called more than once
-        per feature, and so should be idempotent.
-
-        """
-
-        if not self.available:
-            raise DistutilsPlatformError(
-                self.description + " is required, "
-                "but is not available on this platform"
-            )
-
-        dist.include(**self.extras)
-
-        for f in self.require_features:
-            dist.include_feature(f)
-
-    def exclude_from(self, dist):
-        """Ensure feature is excluded from distribution
-
-        You may override this in a subclass to perform additional operations on
-        the distribution.  This method will be called at most once per
-        feature, and only after all included features have been asked to
-        include themselves.
-        """
-
-        dist.exclude(**self.extras)
-
-        if self.remove:
-            for item in self.remove:
-                dist.exclude_package(item)
-
-    def validate(self, dist):
-        """Verify that feature makes sense in context of distribution
-
-        This method is called by the distribution just before it parses its
-        command line.  It checks to ensure that the 'remove' attribute, if any,
-        contains only valid package/module names that are present in the base
-        distribution when 'setup()' is called.  You may override it in a
-        subclass to perform any other required validation of the feature
-        against a target distribution.
-        """
-
-        for item in self.remove:
-            if not dist.has_contents_for(item):
-                raise DistutilsSetupError(
-                    "%s wants to be able to remove %s, but the distribution"
-                    " doesn't contain any packages or modules under %s"
-                    % (self.description, item, item)
-                )
-
-
 class DistDeprecationWarning(SetuptoolsDeprecationWarning):
     """Class for warning about deprecations in dist in
     setuptools. Not ignored by default, unlike DeprecationWarning."""
diff --git a/setuptools/errors.py b/setuptools/errors.py
new file mode 100644
index 00000000..2701747f
--- /dev/null
+++ b/setuptools/errors.py
@@ -0,0 +1,16 @@
+"""setuptools.errors
+
+Provides exceptions used by setuptools modules.
+"""
+
+from distutils.errors import DistutilsError
+
+
+class RemovedCommandError(DistutilsError, RuntimeError):
+    """Error used for commands that have been removed in setuptools.
+
+    Since ``setuptools`` is built on ``distutils``, simply removing a command
+    from ``setuptools`` will make the behavior fall back to ``distutils``; this
+    error is raised if a command exists in ``distutils`` but has been actively
+    removed in ``setuptools``.
+    """
diff --git a/setuptools/extern/__init__.py b/setuptools/extern/__init__.py
index cb2fa329..4e79aa17 100644
--- a/setuptools/extern/__init__.py
+++ b/setuptools/extern/__init__.py
@@ -43,13 +43,6 @@ class VendorImporter:
                 __import__(extant)
                 mod = sys.modules[extant]
                 sys.modules[fullname] = mod
-                # mysterious hack:
-                # Remove the reference to the extant package/module
-                # on later Python versions to cause relative imports
-                # in the vendor package to resolve the same modules
-                # as those going through this importer.
-                if sys.version_info >= (3, ):
-                    del sys.modules[extant]
                 return mod
             except ImportError:
                 pass
@@ -69,5 +62,5 @@ class VendorImporter:
             sys.meta_path.append(self)
 
 
-names = 'six', 'packaging', 'pyparsing',
+names = 'six', 'packaging', 'pyparsing', 'ordered_set',
 VendorImporter(__name__, names, 'setuptools._vendor').install()
diff --git a/setuptools/glibc.py b/setuptools/glibc.py
deleted file mode 100644
index a134591c..00000000
--- a/setuptools/glibc.py
+++ /dev/null
@@ -1,86 +0,0 @@
-# This file originally from pip:
-# https://github.com/pypa/pip/blob/8f4f15a5a95d7d5b511ceaee9ed261176c181970/src/pip/_internal/utils/glibc.py
-from __future__ import absolute_import
-
-import ctypes
-import re
-import warnings
-
-
-def glibc_version_string():
-    "Returns glibc version string, or None if not using glibc."
-
-    # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen
-    # manpage says, "If filename is NULL, then the returned handle is for the
-    # main program". This way we can let the linker do the work to figure out
-    # which libc our process is actually using.
-    process_namespace = ctypes.CDLL(None)
-    try:
-        gnu_get_libc_version = process_namespace.gnu_get_libc_version
-    except AttributeError:
-        # Symbol doesn't exist -> therefore, we are not linked to
-        # glibc.
-        return None
-
-    # Call gnu_get_libc_version, which returns a string like "2.5"
-    gnu_get_libc_version.restype = ctypes.c_char_p
-    version_str = gnu_get_libc_version()
-    # py2 / py3 compatibility:
-    if not isinstance(version_str, str):
-        version_str = version_str.decode("ascii")
-
-    return version_str
-
-
-# Separated out from have_compatible_glibc for easier unit testing
-def check_glibc_version(version_str, required_major, minimum_minor):
-    # Parse string and check against requested version.
-    #
-    # We use a regexp instead of str.split because we want to discard any
-    # random junk that might come after the minor version -- this might happen
-    # in patched/forked versions of glibc (e.g. Linaro's version of glibc
-    # uses version strings like "2.20-2014.11"). See gh-3588.
-    m = re.match(r"(?P<major>[0-9]+)\.(?P<minor>[0-9]+)", version_str)
-    if not m:
-        warnings.warn("Expected glibc version with 2 components major.minor,"
-                      " got: %s" % version_str, RuntimeWarning)
-        return False
-    return (int(m.group("major")) == required_major and
-            int(m.group("minor")) >= minimum_minor)
-
-
-def have_compatible_glibc(required_major, minimum_minor):
-    version_str = glibc_version_string()
-    if version_str is None:
-        return False
-    return check_glibc_version(version_str, required_major, minimum_minor)
-
-
-# platform.libc_ver regularly returns completely nonsensical glibc
-# versions. E.g. on my computer, platform says:
-#
-#   ~$ python2.7 -c 'import platform; print(platform.libc_ver())'
-#   ('glibc', '2.7')
-#   ~$ python3.5 -c 'import platform; print(platform.libc_ver())'
-#   ('glibc', '2.9')
-#
-# But the truth is:
-#
-#   ~$ ldd --version
-#   ldd (Debian GLIBC 2.22-11) 2.22
-#
-# This is unfortunate, because it means that the linehaul data on libc
-# versions that was generated by pip 8.1.2 and earlier is useless and
-# misleading. Solution: instead of using platform, use our code that actually
-# works.
-def libc_ver():
-    """Try to determine the glibc version
-
-    Returns a tuple of strings (lib, version) which default to empty strings
-    in case the lookup fails.
-    """
-    glibc_version = glibc_version_string()
-    if glibc_version is None:
-        return ("", "")
-    else:
-        return ("glibc", glibc_version)
diff --git a/setuptools/installer.py b/setuptools/installer.py
new file mode 100644
index 00000000..1f183bd9
--- /dev/null
+++ b/setuptools/installer.py
@@ -0,0 +1,150 @@
+import glob
+import os
+import subprocess
+import sys
+from distutils import log
+from distutils.errors import DistutilsError
+
+import pkg_resources
+from setuptools.command.easy_install import easy_install
+from setuptools.extern import six
+from setuptools.wheel import Wheel
+
+from .py31compat import TemporaryDirectory
+
+
+def _fixup_find_links(find_links):
+    """Ensure find-links option end-up being a list of strings."""
+    if isinstance(find_links, six.string_types):
+        return find_links.split()
+    assert isinstance(find_links, (tuple, list))
+    return find_links
+
+
+def _legacy_fetch_build_egg(dist, req):
+    """Fetch an egg needed for building.
+
+    Legacy path using EasyInstall.
+    """
+    tmp_dist = dist.__class__({'script_args': ['easy_install']})
+    opts = tmp_dist.get_option_dict('easy_install')
+    opts.clear()
+    opts.update(
+        (k, v)
+        for k, v in dist.get_option_dict('easy_install').items()
+        if k in (
+            # don't use any other settings
+            'find_links', 'site_dirs', 'index_url',
+            'optimize', 'site_dirs', 'allow_hosts',
+        ))
+    if dist.dependency_links:
+        links = dist.dependency_links[:]
+        if 'find_links' in opts:
+            links = _fixup_find_links(opts['find_links'][1]) + links
+        opts['find_links'] = ('setup', links)
+    install_dir = dist.get_egg_cache_dir()
+    cmd = easy_install(
+        tmp_dist, args=["x"], install_dir=install_dir,
+        exclude_scripts=True,
+        always_copy=False, build_directory=None, editable=False,
+        upgrade=False, multi_version=True, no_report=True, user=False
+    )
+    cmd.ensure_finalized()
+    return cmd.easy_install(req)
+
+
+def fetch_build_egg(dist, req):
+    """Fetch an egg needed for building.
+
+    Use pip/wheel to fetch/build a wheel."""
+    # Check pip is available.
+    try:
+        pkg_resources.get_distribution('pip')
+    except pkg_resources.DistributionNotFound:
+        dist.announce(
+            'WARNING: The pip package is not available, falling back '
+            'to EasyInstall for handling setup_requires/test_requires; '
+            'this is deprecated and will be removed in a future version.',
+            log.WARN
+        )
+        return _legacy_fetch_build_egg(dist, req)
+    # Warn if wheel is not.
+    try:
+        pkg_resources.get_distribution('wheel')
+    except pkg_resources.DistributionNotFound:
+        dist.announce('WARNING: The wheel package is not available.', log.WARN)
+    # Ignore environment markers; if supplied, it is required.
+    req = strip_marker(req)
+    # Take easy_install options into account, but do not override relevant
+    # pip environment variables (like PIP_INDEX_URL or PIP_QUIET); they'll
+    # take precedence.
+    opts = dist.get_option_dict('easy_install')
+    if 'allow_hosts' in opts:
+        raise DistutilsError('the `allow-hosts` option is not supported '
+                             'when using pip to install requirements.')
+    if 'PIP_QUIET' in os.environ or 'PIP_VERBOSE' in os.environ:
+        quiet = False
+    else:
+        quiet = True
+    if 'PIP_INDEX_URL' in os.environ:
+        index_url = None
+    elif 'index_url' in opts:
+        index_url = opts['index_url'][1]
+    else:
+        index_url = None
+    if 'find_links' in opts:
+        find_links = _fixup_find_links(opts['find_links'][1])[:]
+    else:
+        find_links = []
+    if dist.dependency_links:
+        find_links.extend(dist.dependency_links)
+    eggs_dir = os.path.realpath(dist.get_egg_cache_dir())
+    environment = pkg_resources.Environment()
+    for egg_dist in pkg_resources.find_distributions(eggs_dir):
+        if egg_dist in req and environment.can_add(egg_dist):
+            return egg_dist
+    with TemporaryDirectory() as tmpdir:
+        cmd = [
+            sys.executable, '-m', 'pip',
+            '--disable-pip-version-check',
+            'wheel', '--no-deps',
+            '-w', tmpdir,
+        ]
+        if quiet:
+            cmd.append('--quiet')
+        if index_url is not None:
+            cmd.extend(('--index-url', index_url))
+        if find_links is not None:
+            for link in find_links:
+                cmd.extend(('--find-links', link))
+        # If requirement is a PEP 508 direct URL, directly pass
+        # the URL to pip, as `req @ url` does not work on the
+        # command line.
+        if req.url:
+            cmd.append(req.url)
+        else:
+            cmd.append(str(req))
+        try:
+            subprocess.check_call(cmd)
+        except subprocess.CalledProcessError as e:
+            raise DistutilsError(str(e))
+        wheel = Wheel(glob.glob(os.path.join(tmpdir, '*.whl'))[0])
+        dist_location = os.path.join(eggs_dir, wheel.egg_name())
+        wheel.install_as_egg(dist_location)
+        dist_metadata = pkg_resources.PathMetadata(
+            dist_location, os.path.join(dist_location, 'EGG-INFO'))
+        dist = pkg_resources.Distribution.from_filename(
+            dist_location, metadata=dist_metadata)
+        return dist
+
+
+def strip_marker(req):
+    """
+    Return a new requirement without the environment marker to avoid
+    calling pip with something like `babel; extra == "i18n"`, which
+    would always be ignored.
+    """
+    # create a copy to avoid mutating the input
+    req = pkg_resources.Requirement.parse(str(req))
+    req.marker = None
+    return req
diff --git a/setuptools/lib2to3_ex.py b/setuptools/lib2to3_ex.py
index 4b1a73fe..017f7285 100644
--- a/setuptools/lib2to3_ex.py
+++ b/setuptools/lib2to3_ex.py
@@ -7,11 +7,13 @@ Customized Mixin2to3 support:
 This module raises an ImportError on Python 2.
 """
 
+import warnings
 from distutils.util import Mixin2to3 as _Mixin2to3
 from distutils import log
 from lib2to3.refactor import RefactoringTool, get_fixers_from_package
 
 import setuptools
+from ._deprecation_warning import SetuptoolsDeprecationWarning
 
 
 class DistutilsRefactoringTool(RefactoringTool):
@@ -33,6 +35,13 @@ class Mixin2to3(_Mixin2to3):
             return
         if not files:
             return
+
+        warnings.warn(
+            "2to3 support is deprecated. If the project still "
+            "requires Python 2 support, please migrate to "
+            "a single-codebase solution or employ an "
+            "independent conversion process.",
+            SetuptoolsDeprecationWarning)
         log.info("Fixing " + " ".join(files))
         self.__build_fixer_names()
         self.__exclude_fixers()
diff --git a/setuptools/msvc.py b/setuptools/msvc.py
index b9c472f1..213e39c9 100644
--- a/setuptools/msvc.py
+++ b/setuptools/msvc.py
@@ -11,16 +11,22 @@ Microsoft Visual C++ 9.0:
 Microsoft Visual C++ 10.0:
     Microsoft Windows SDK 7.1 (x86, x64, ia64)
 
-Microsoft Visual C++ 14.0:
+Microsoft Visual C++ 14.X:
     Microsoft Visual C++ Build Tools 2015 (x86, x64, arm)
-    Microsoft Visual Studio 2017 (x86, x64, arm, arm64)
     Microsoft Visual Studio Build Tools 2017 (x86, x64, arm, arm64)
+    Microsoft Visual Studio Build Tools 2019 (x86, x64, arm, arm64)
+
+This may also support compilers shipped with compatible Visual Studio versions.
 """
 
-import os
+import json
+from io import open
+from os import listdir, pathsep
+from os.path import join, isfile, isdir, dirname
 import sys
 import platform
 import itertools
+import subprocess
 import distutils.errors
 from setuptools.extern.packaging.version import LegacyVersion
 
@@ -30,12 +36,9 @@ from .monkey import get_unpatched
 
 if platform.system() == 'Windows':
     from setuptools.extern.six.moves import winreg
-    safe_env = os.environ
+    from os import environ
 else:
-    """
-    Mock winreg and environ so the module can be imported
-    on this platform.
-    """
+    # Mock winreg and environ so the module can be imported on this platform.
 
     class winreg:
         HKEY_USERS = None
@@ -43,7 +46,7 @@ else:
         HKEY_LOCAL_MACHINE = None
         HKEY_CLASSES_ROOT = None
 
-    safe_env = dict()
+    environ = dict()
 
 _msvc9_suppress_errors = (
     # msvc9compiler isn't available on some platforms
@@ -63,15 +66,13 @@ except _msvc9_suppress_errors:
 def msvc9_find_vcvarsall(version):
     """
     Patched "distutils.msvc9compiler.find_vcvarsall" to use the standalone
-    compiler build for Python (VCForPython). Fall back to original behavior
-    when the standalone compiler is not available.
+    compiler build for Python
+    (VCForPython / Microsoft Visual C++ Compiler for Python 2.7).
 
-    Redirect the path of "vcvarsall.bat".
+    Fall back to original behavior when the standalone compiler is not
+    available.
 
-    Known supported compilers
-    -------------------------
-    Microsoft Visual C++ 9.0:
-        Microsoft Visual C++ Compiler for Python 2.7 (x86, amd64)
+    Redirect the path of "vcvarsall.bat".
 
     Parameters
     ----------
@@ -80,24 +81,25 @@ def msvc9_find_vcvarsall(version):
 
     Return
     ------
-    vcvarsall.bat path: str
+    str
+        vcvarsall.bat path
     """
-    VC_BASE = r'Software\%sMicrosoft\DevDiv\VCForPython\%0.1f'
-    key = VC_BASE % ('', version)
+    vc_base = r'Software\%sMicrosoft\DevDiv\VCForPython\%0.1f'
+    key = vc_base % ('', version)
     try:
         # Per-user installs register the compiler path here
         productdir = Reg.get_value(key, "installdir")
     except KeyError:
         try:
             # All-user installs on a 64-bit system register here
-            key = VC_BASE % ('Wow6432Node\\', version)
+            key = vc_base % ('Wow6432Node\\', version)
             productdir = Reg.get_value(key, "installdir")
         except KeyError:
             productdir = None
 
     if productdir:
-        vcvarsall = os.path.os.path.join(productdir, "vcvarsall.bat")
-        if os.path.isfile(vcvarsall):
+        vcvarsall = join(productdir, "vcvarsall.bat")
+        if isfile(vcvarsall):
             return vcvarsall
 
     return get_unpatched(msvc9_find_vcvarsall)(version)
@@ -106,20 +108,10 @@ def msvc9_find_vcvarsall(version):
 def msvc9_query_vcvarsall(ver, arch='x86', *args, **kwargs):
     """
     Patched "distutils.msvc9compiler.query_vcvarsall" for support extra
-    compilers.
+    Microsoft Visual C++ 9.0 and 10.0 compilers.
 
     Set environment without use of "vcvarsall.bat".
 
-    Known supported compilers
-    -------------------------
-    Microsoft Visual C++ 9.0:
-        Microsoft Visual C++ Compiler for Python 2.7 (x86, amd64)
-        Microsoft Windows SDK 6.1 (x86, x64, ia64)
-        Microsoft Windows SDK 7.0 (x86, x64, ia64)
-
-    Microsoft Visual C++ 10.0:
-        Microsoft Windows SDK 7.1 (x86, x64, ia64)
-
     Parameters
     ----------
     ver: float
@@ -129,9 +121,10 @@ def msvc9_query_vcvarsall(ver, arch='x86', *args, **kwargs):
 
     Return
     ------
-    environment: dict
+    dict
+        environment
     """
-    # Try to get environement from vcvarsall.bat (Classical way)
+    # Try to get environment from vcvarsall.bat (Classical way)
     try:
         orig = get_unpatched(msvc9_query_vcvarsall)
         return orig(ver, arch, *args, **kwargs)
@@ -150,20 +143,161 @@ def msvc9_query_vcvarsall(ver, arch='x86', *args, **kwargs):
         raise
 
 
+def _msvc14_find_vc2015():
+    """Python 3.8 "distutils/_msvccompiler.py" backport"""
+    try:
+        key = winreg.OpenKey(
+            winreg.HKEY_LOCAL_MACHINE,
+            r"Software\Microsoft\VisualStudio\SxS\VC7",
+            0,
+            winreg.KEY_READ | winreg.KEY_WOW64_32KEY
+        )
+    except OSError:
+        return None, None
+
+    best_version = 0
+    best_dir = None
+    with key:
+        for i in itertools.count():
+            try:
+                v, vc_dir, vt = winreg.EnumValue(key, i)
+            except OSError:
+                break
+            if v and vt == winreg.REG_SZ and isdir(vc_dir):
+                try:
+                    version = int(float(v))
+                except (ValueError, TypeError):
+                    continue
+                if version >= 14 and version > best_version:
+                    best_version, best_dir = version, vc_dir
+    return best_version, best_dir
+
+
+def _msvc14_find_vc2017():
+    """Python 3.8 "distutils/_msvccompiler.py" backport
+
+    Returns "15, path" based on the result of invoking vswhere.exe
+    If no install is found, returns "None, None"
+
+    The version is returned to avoid unnecessarily changing the function
+    result. It may be ignored when the path is not None.
+
+    If vswhere.exe is not available, by definition, VS 2017 is not
+    installed.
+    """
+    root = environ.get("ProgramFiles(x86)") or environ.get("ProgramFiles")
+    if not root:
+        return None, None
+
+    try:
+        path = subprocess.check_output([
+            join(root, "Microsoft Visual Studio", "Installer", "vswhere.exe"),
+            "-latest",
+            "-prerelease",
+            "-requires", "Microsoft.VisualStudio.Component.VC.Tools.x86.x64",
+            "-property", "installationPath",
+            "-products", "*",
+        ]).decode(encoding="mbcs", errors="strict").strip()
+    except (subprocess.CalledProcessError, OSError, UnicodeDecodeError):
+        return None, None
+
+    path = join(path, "VC", "Auxiliary", "Build")
+    if isdir(path):
+        return 15, path
+
+    return None, None
+
+
+PLAT_SPEC_TO_RUNTIME = {
+    'x86': 'x86',
+    'x86_amd64': 'x64',
+    'x86_arm': 'arm',
+    'x86_arm64': 'arm64'
+}
+
+
+def _msvc14_find_vcvarsall(plat_spec):
+    """Python 3.8 "distutils/_msvccompiler.py" backport"""
+    _, best_dir = _msvc14_find_vc2017()
+    vcruntime = None
+
+    if plat_spec in PLAT_SPEC_TO_RUNTIME:
+        vcruntime_plat = PLAT_SPEC_TO_RUNTIME[plat_spec]
+    else:
+        vcruntime_plat = 'x64' if 'amd64' in plat_spec else 'x86'
+
+    if best_dir:
+        vcredist = join(best_dir, "..", "..", "redist", "MSVC", "**",
+                        vcruntime_plat, "Microsoft.VC14*.CRT",
+                        "vcruntime140.dll")
+        try:
+            import glob
+            vcruntime = glob.glob(vcredist, recursive=True)[-1]
+        except (ImportError, OSError, LookupError):
+            vcruntime = None
+
+    if not best_dir:
+        best_version, best_dir = _msvc14_find_vc2015()
+        if best_version:
+            vcruntime = join(best_dir, 'redist', vcruntime_plat,
+                             "Microsoft.VC140.CRT", "vcruntime140.dll")
+
+    if not best_dir:
+        return None, None
+
+    vcvarsall = join(best_dir, "vcvarsall.bat")
+    if not isfile(vcvarsall):
+        return None, None
+
+    if not vcruntime or not isfile(vcruntime):
+        vcruntime = None
+
+    return vcvarsall, vcruntime
+
+
+def _msvc14_get_vc_env(plat_spec):
+    """Python 3.8 "distutils/_msvccompiler.py" backport"""
+    if "DISTUTILS_USE_SDK" in environ:
+        return {
+            key.lower(): value
+            for key, value in environ.items()
+        }
+
+    vcvarsall, vcruntime = _msvc14_find_vcvarsall(plat_spec)
+    if not vcvarsall:
+        raise distutils.errors.DistutilsPlatformError(
+            "Unable to find vcvarsall.bat"
+        )
+
+    try:
+        out = subprocess.check_output(
+            'cmd /u /c "{}" {} && set'.format(vcvarsall, plat_spec),
+            stderr=subprocess.STDOUT,
+        ).decode('utf-16le', errors='replace')
+    except subprocess.CalledProcessError as exc:
+        raise distutils.errors.DistutilsPlatformError(
+            "Error executing {}".format(exc.cmd)
+        )
+
+    env = {
+        key.lower(): value
+        for key, _, value in
+        (line.partition('=') for line in out.splitlines())
+        if key and value
+    }
+
+    if vcruntime:
+        env['py_vcruntime_redist'] = vcruntime
+    return env
+
+
 def msvc14_get_vc_env(plat_spec):
     """
     Patched "distutils._msvccompiler._get_vc_env" for support extra
-    compilers.
+    Microsoft Visual C++ 14.X compilers.
 
     Set environment without use of "vcvarsall.bat".
 
-    Known supported compilers
-    -------------------------
-    Microsoft Visual C++ 14.0:
-        Microsoft Visual C++ Build Tools 2015 (x86, x64, arm)
-        Microsoft Visual Studio 2017 (x86, x64, arm, arm64)
-        Microsoft Visual Studio Build Tools 2017 (x86, x64, arm, arm64)
-
     Parameters
     ----------
     plat_spec: str
@@ -171,18 +305,13 @@ def msvc14_get_vc_env(plat_spec):
 
     Return
     ------
-    environment: dict
+    dict
+        environment
     """
-    # Try to get environment from vcvarsall.bat (Classical way)
-    try:
-        return get_unpatched(msvc14_get_vc_env)(plat_spec)
-    except distutils.errors.DistutilsPlatformError:
-        # Pass error Vcvarsall.bat is missing
-        pass
 
-    # If error, try to set environment directly
+    # Always use backport from CPython 3.8
     try:
-        return EnvironmentInfo(plat_spec, vc_min_ver=14.0).return_env()
+        return _msvc14_get_vc_env(plat_spec)
     except distutils.errors.DistutilsPlatformError as exc:
         _augment_exception(exc, 14.0)
         raise
@@ -217,9 +346,9 @@ def _augment_exception(exc, version, arch=''):
         if version == 9.0:
             if arch.lower().find('ia64') > -1:
                 # For VC++ 9.0, if IA64 support is needed, redirect user
-                # to Windows SDK 7.0
-                message += ' Get it with "Microsoft Windows SDK 7.0": '
-                message += msdownload % 3138
+                # to Windows SDK 7.0.
+                # Note: No download link available from Microsoft.
+                message += ' Get it with "Microsoft Windows SDK 7.0"'
             else:
                 # For VC++ 9.0 redirect user to Vc++ for Python 2.7 :
                 # This redirection link is maintained by Microsoft.
@@ -230,8 +359,8 @@ def _augment_exception(exc, version, arch=''):
             message += ' Get it with "Microsoft Windows SDK 7.1": '
             message += msdownload % 8279
         elif version >= 14.0:
-            # For VC++ 14.0 Redirect user to Visual C++ Build Tools
-            message += (' Get it with "Microsoft Visual C++ Build Tools": '
+            # For VC++ 14.X Redirect user to latest Visual C++ Build Tools
+            message += (' Get it with "Build Tools for Visual Studio": '
                         r'https://visualstudio.microsoft.com/downloads/')
 
     exc.args = (message, )
@@ -239,26 +368,50 @@ def _augment_exception(exc, version, arch=''):
 
 class PlatformInfo:
     """
-    Current and Target Architectures informations.
+    Current and Target Architectures information.
 
     Parameters
     ----------
     arch: str
         Target architecture.
     """
-    current_cpu = safe_env.get('processor_architecture', '').lower()
+    current_cpu = environ.get('processor_architecture', '').lower()
 
     def __init__(self, arch):
         self.arch = arch.lower().replace('x64', 'amd64')
 
     @property
     def target_cpu(self):
+        """
+        Return Target CPU architecture.
+
+        Return
+        ------
+        str
+            Target CPU
+        """
         return self.arch[self.arch.find('_') + 1:]
 
     def target_is_x86(self):
+        """
+        Return True if target CPU is x86 32 bits..
+
+        Return
+        ------
+        bool
+            CPU is x86 32 bits
+        """
         return self.target_cpu == 'x86'
 
     def current_is_x86(self):
+        """
+        Return True if current CPU is x86 32 bits..
+
+        Return
+        ------
+        bool
+            CPU is x86 32 bits
+        """
         return self.current_cpu == 'x86'
 
     def current_dir(self, hidex86=False, x64=False):
@@ -274,8 +427,8 @@ class PlatformInfo:
 
         Return
         ------
-        subfolder: str
-            '\target', or '' (see hidex86 parameter)
+        str
+            subfolder: '\target', or '' (see hidex86 parameter)
         """
         return (
             '' if (self.current_cpu == 'x86' and hidex86) else
@@ -296,8 +449,8 @@ class PlatformInfo:
 
         Return
         ------
-        subfolder: str
-            '\current', or '' (see hidex86 parameter)
+        str
+            subfolder: '\current', or '' (see hidex86 parameter)
         """
         return (
             '' if (self.target_cpu == 'x86' and hidex86) else
@@ -312,13 +465,13 @@ class PlatformInfo:
         Parameters
         ----------
         forcex86: bool
-            Use 'x86' as current architecture even if current acritecture is
+            Use 'x86' as current architecture even if current architecture is
             not x86.
 
         Return
         ------
-        subfolder: str
-            '' if target architecture is current architecture,
+        str
+            subfolder: '' if target architecture is current architecture,
             '\current_target' if not.
         """
         current = 'x86' if forcex86 else self.current_cpu
@@ -330,7 +483,7 @@ class PlatformInfo:
 
 class RegistryInfo:
     """
-    Microsoft Visual Studio related registry informations.
+    Microsoft Visual Studio related registry information.
 
     Parameters
     ----------
@@ -349,6 +502,11 @@ class RegistryInfo:
     def visualstudio(self):
         """
         Microsoft Visual Studio root registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
         return 'VisualStudio'
 
@@ -356,27 +514,47 @@ class RegistryInfo:
     def sxs(self):
         """
         Microsoft Visual Studio SxS registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
-        return os.path.join(self.visualstudio, 'SxS')
+        return join(self.visualstudio, 'SxS')
 
     @property
     def vc(self):
         """
         Microsoft Visual C++ VC7 registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
-        return os.path.join(self.sxs, 'VC7')
+        return join(self.sxs, 'VC7')
 
     @property
     def vs(self):
         """
         Microsoft Visual Studio VS7 registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
-        return os.path.join(self.sxs, 'VS7')
+        return join(self.sxs, 'VS7')
 
     @property
     def vc_for_python(self):
         """
         Microsoft Visual C++ for Python registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
         return r'DevDiv\VCForPython'
 
@@ -384,6 +562,11 @@ class RegistryInfo:
     def microsoft_sdk(self):
         """
         Microsoft SDK registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
         return 'Microsoft SDKs'
 
@@ -391,20 +574,35 @@ class RegistryInfo:
     def windows_sdk(self):
         """
         Microsoft Windows/Platform SDK registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
-        return os.path.join(self.microsoft_sdk, 'Windows')
+        return join(self.microsoft_sdk, 'Windows')
 
     @property
     def netfx_sdk(self):
         """
         Microsoft .NET Framework SDK registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
-        return os.path.join(self.microsoft_sdk, 'NETFXSDK')
+        return join(self.microsoft_sdk, 'NETFXSDK')
 
     @property
     def windows_kits_roots(self):
         """
         Microsoft Windows Kits Roots registry key.
+
+        Return
+        ------
+        str
+            Registry key
         """
         return r'Windows Kits\Installed Roots'
 
@@ -421,10 +619,11 @@ class RegistryInfo:
 
         Return
         ------
-        str: value
+        str
+            Registry key
         """
         node64 = '' if self.pi.current_is_x86() or x86 else 'Wow6432Node'
-        return os.path.join('Software', node64, 'Microsoft', key)
+        return join('Software', node64, 'Microsoft', key)
 
     def lookup(self, key, name):
         """
@@ -439,18 +638,19 @@ class RegistryInfo:
 
         Return
         ------
-        str: value
+        str
+            value
         """
-        KEY_READ = winreg.KEY_READ
+        key_read = winreg.KEY_READ
         openkey = winreg.OpenKey
         ms = self.microsoft
         for hkey in self.HKEYS:
             try:
-                bkey = openkey(hkey, ms(key), 0, KEY_READ)
+                bkey = openkey(hkey, ms(key), 0, key_read)
             except (OSError, IOError):
                 if not self.pi.current_is_x86():
                     try:
-                        bkey = openkey(hkey, ms(key, True), 0, KEY_READ)
+                        bkey = openkey(hkey, ms(key, True), 0, key_read)
                     except (OSError, IOError):
                         continue
                 else:
@@ -463,7 +663,7 @@ class RegistryInfo:
 
 class SystemInfo:
     """
-    Microsoft Windows and Visual Studio related system inormations.
+    Microsoft Windows and Visual Studio related system information.
 
     Parameters
     ----------
@@ -474,30 +674,52 @@ class SystemInfo:
     """
 
     # Variables and properties in this class use originals CamelCase variables
-    # names from Microsoft source files for more easy comparaison.
-    WinDir = safe_env.get('WinDir', '')
-    ProgramFiles = safe_env.get('ProgramFiles', '')
-    ProgramFilesx86 = safe_env.get('ProgramFiles(x86)', ProgramFiles)
+    # names from Microsoft source files for more easy comparison.
+    WinDir = environ.get('WinDir', '')
+    ProgramFiles = environ.get('ProgramFiles', '')
+    ProgramFilesx86 = environ.get('ProgramFiles(x86)', ProgramFiles)
 
     def __init__(self, registry_info, vc_ver=None):
         self.ri = registry_info
         self.pi = self.ri.pi
-        self.vc_ver = vc_ver or self._find_latest_available_vc_ver()
 
-    def _find_latest_available_vc_ver(self):
-        try:
-            return self.find_available_vc_vers()[-1]
-        except IndexError:
-            err = 'No Microsoft Visual C++ version found'
-            raise distutils.errors.DistutilsPlatformError(err)
+        self.known_vs_paths = self.find_programdata_vs_vers()
+
+        # Except for VS15+, VC version is aligned with VS version
+        self.vs_ver = self.vc_ver = (
+            vc_ver or self._find_latest_available_vs_ver())
 
-    def find_available_vc_vers(self):
+    def _find_latest_available_vs_ver(self):
         """
-        Find all available Microsoft Visual C++ versions.
+        Find the latest VC version
+
+        Return
+        ------
+        float
+            version
+        """
+        reg_vc_vers = self.find_reg_vs_vers()
+
+        if not (reg_vc_vers or self.known_vs_paths):
+            raise distutils.errors.DistutilsPlatformError(
+                'No Microsoft Visual C++ version found')
+
+        vc_vers = set(reg_vc_vers)
+        vc_vers.update(self.known_vs_paths)
+        return sorted(vc_vers)[-1]
+
+    def find_reg_vs_vers(self):
+        """
+        Find Microsoft Visual Studio versions available in registry.
+
+        Return
+        ------
+        list of float
+            Versions
         """
         ms = self.ri.microsoft
         vckeys = (self.ri.vc, self.ri.vc_for_python, self.ri.vs)
-        vc_vers = []
+        vs_vers = []
         for hkey in self.ri.HKEYS:
             for key in vckeys:
                 try:
@@ -508,49 +730,108 @@ class SystemInfo:
                 for i in range(values):
                     try:
                         ver = float(winreg.EnumValue(bkey, i)[0])
-                        if ver not in vc_vers:
-                            vc_vers.append(ver)
+                        if ver not in vs_vers:
+                            vs_vers.append(ver)
                     except ValueError:
                         pass
                 for i in range(subkeys):
                     try:
                         ver = float(winreg.EnumKey(bkey, i))
-                        if ver not in vc_vers:
-                            vc_vers.append(ver)
+                        if ver not in vs_vers:
+                            vs_vers.append(ver)
                     except ValueError:
                         pass
-        return sorted(vc_vers)
+        return sorted(vs_vers)
+
+    def find_programdata_vs_vers(self):
+        r"""
+        Find Visual studio 2017+ versions from information in
+        "C:\ProgramData\Microsoft\VisualStudio\Packages\_Instances".
+
+        Return
+        ------
+        dict
+            float version as key, path as value.
+        """
+        vs_versions = {}
+        instances_dir = \
+            r'C:\ProgramData\Microsoft\VisualStudio\Packages\_Instances'
+
+        try:
+            hashed_names = listdir(instances_dir)
+
+        except (OSError, IOError):
+            # Directory not exists with all Visual Studio versions
+            return vs_versions
+
+        for name in hashed_names:
+            try:
+                # Get VS installation path from "state.json" file
+                state_path = join(instances_dir, name, 'state.json')
+                with open(state_path, 'rt', encoding='utf-8') as state_file:
+                    state = json.load(state_file)
+                vs_path = state['installationPath']
+
+                # Raises OSError if this VS installation does not contain VC
+                listdir(join(vs_path, r'VC\Tools\MSVC'))
+
+                # Store version and path
+                vs_versions[self._as_float_version(
+                    state['installationVersion'])] = vs_path
+
+            except (OSError, IOError, KeyError):
+                # Skip if "state.json" file is missing or bad format
+                continue
+
+        return vs_versions
+
+    @staticmethod
+    def _as_float_version(version):
+        """
+        Return a string version as a simplified float version (major.minor)
+
+        Parameters
+        ----------
+        version: str
+            Version.
+
+        Return
+        ------
+        float
+            version
+        """
+        return float('.'.join(version.split('.')[:2]))
 
     @property
     def VSInstallDir(self):
         """
         Microsoft Visual Studio directory.
+
+        Return
+        ------
+        str
+            path
         """
         # Default path
-        name = 'Microsoft Visual Studio %0.1f' % self.vc_ver
-        default = os.path.join(self.ProgramFilesx86, name)
+        default = join(self.ProgramFilesx86,
+                       'Microsoft Visual Studio %0.1f' % self.vs_ver)
 
         # Try to get path from registry, if fail use default path
-        return self.ri.lookup(self.ri.vs, '%0.1f' % self.vc_ver) or default
+        return self.ri.lookup(self.ri.vs, '%0.1f' % self.vs_ver) or default
 
     @property
     def VCInstallDir(self):
         """
         Microsoft Visual C++ directory.
-        """
-        self.VSInstallDir
 
-        guess_vc = self._guess_vc() or self._guess_vc_legacy()
-
-        # Try to get "VC++ for Python" path from registry as default path
-        reg_path = os.path.join(self.ri.vc_for_python, '%0.1f' % self.vc_ver)
-        python_vc = self.ri.lookup(reg_path, 'installdir')
-        default_vc = os.path.join(python_vc, 'VC') if python_vc else guess_vc
-
-        # Try to get path from registry, if fail use default path
-        path = self.ri.lookup(self.ri.vc, '%0.1f' % self.vc_ver) or default_vc
+        Return
+        ------
+        str
+            path
+        """
+        path = self._guess_vc() or self._guess_vc_legacy()
 
-        if not os.path.isdir(path):
+        if not isdir(path):
             msg = 'Microsoft Visual C++ directory not found'
             raise distutils.errors.DistutilsPlatformError(msg)
 
@@ -558,186 +839,256 @@ class SystemInfo:
 
     def _guess_vc(self):
         """
-        Locate Visual C for 2017
+        Locate Visual C++ for VS2017+.
+
+        Return
+        ------
+        str
+            path
         """
-        if self.vc_ver <= 14.0:
-            return
+        if self.vs_ver <= 14.0:
+            return ''
+
+        try:
+            # First search in known VS paths
+            vs_dir = self.known_vs_paths[self.vs_ver]
+        except KeyError:
+            # Else, search with path from registry
+            vs_dir = self.VSInstallDir
+
+        guess_vc = join(vs_dir, r'VC\Tools\MSVC')
 
-        default = r'VC\Tools\MSVC'
-        guess_vc = os.path.join(self.VSInstallDir, default)
         # Subdir with VC exact version as name
         try:
-            vc_exact_ver = os.listdir(guess_vc)[-1]
-            return os.path.join(guess_vc, vc_exact_ver)
+            # Update the VC version with real one instead of VS version
+            vc_ver = listdir(guess_vc)[-1]
+            self.vc_ver = self._as_float_version(vc_ver)
+            return join(guess_vc, vc_ver)
         except (OSError, IOError, IndexError):
-            pass
+            return ''
 
     def _guess_vc_legacy(self):
         """
-        Locate Visual C for versions prior to 2017
+        Locate Visual C++ for versions prior to 2017.
+
+        Return
+        ------
+        str
+            path
         """
-        default = r'Microsoft Visual Studio %0.1f\VC' % self.vc_ver
-        return os.path.join(self.ProgramFilesx86, default)
+        default = join(self.ProgramFilesx86,
+                       r'Microsoft Visual Studio %0.1f\VC' % self.vs_ver)
+
+        # Try to get "VC++ for Python" path from registry as default path
+        reg_path = join(self.ri.vc_for_python, '%0.1f' % self.vs_ver)
+        python_vc = self.ri.lookup(reg_path, 'installdir')
+        default_vc = join(python_vc, 'VC') if python_vc else default
+
+        # Try to get path from registry, if fail use default path
+        return self.ri.lookup(self.ri.vc, '%0.1f' % self.vs_ver) or default_vc
 
     @property
     def WindowsSdkVersion(self):
         """
         Microsoft Windows SDK versions for specified MSVC++ version.
-        """
-        if self.vc_ver <= 9.0:
-            return ('7.0', '6.1', '6.0a')
-        elif self.vc_ver == 10.0:
-            return ('7.1', '7.0a')
-        elif self.vc_ver == 11.0:
-            return ('8.0', '8.0a')
-        elif self.vc_ver == 12.0:
-            return ('8.1', '8.1a')
-        elif self.vc_ver >= 14.0:
-            return ('10.0', '8.1')
+
+        Return
+        ------
+        tuple of str
+            versions
+        """
+        if self.vs_ver <= 9.0:
+            return '7.0', '6.1', '6.0a'
+        elif self.vs_ver == 10.0:
+            return '7.1', '7.0a'
+        elif self.vs_ver == 11.0:
+            return '8.0', '8.0a'
+        elif self.vs_ver == 12.0:
+            return '8.1', '8.1a'
+        elif self.vs_ver >= 14.0:
+            return '10.0', '8.1'
 
     @property
     def WindowsSdkLastVersion(self):
         """
-        Microsoft Windows SDK last version
+        Microsoft Windows SDK last version.
+
+        Return
+        ------
+        str
+            version
         """
-        return self._use_last_dir_name(os.path.join(
-            self.WindowsSdkDir, 'lib'))
+        return self._use_last_dir_name(join(self.WindowsSdkDir, 'lib'))
 
     @property
     def WindowsSdkDir(self):
         """
         Microsoft Windows SDK directory.
+
+        Return
+        ------
+        str
+            path
         """
         sdkdir = ''
         for ver in self.WindowsSdkVersion:
             # Try to get it from registry
-            loc = os.path.join(self.ri.windows_sdk, 'v%s' % ver)
+            loc = join(self.ri.windows_sdk, 'v%s' % ver)
             sdkdir = self.ri.lookup(loc, 'installationfolder')
             if sdkdir:
                 break
-        if not sdkdir or not os.path.isdir(sdkdir):
+        if not sdkdir or not isdir(sdkdir):
             # Try to get "VC++ for Python" version from registry
-            path = os.path.join(self.ri.vc_for_python, '%0.1f' % self.vc_ver)
+            path = join(self.ri.vc_for_python, '%0.1f' % self.vc_ver)
             install_base = self.ri.lookup(path, 'installdir')
             if install_base:
-                sdkdir = os.path.join(install_base, 'WinSDK')
-        if not sdkdir or not os.path.isdir(sdkdir):
+                sdkdir = join(install_base, 'WinSDK')
+        if not sdkdir or not isdir(sdkdir):
             # If fail, use default new path
             for ver in self.WindowsSdkVersion:
                 intver = ver[:ver.rfind('.')]
-                path = r'Microsoft SDKs\Windows Kits\%s' % (intver)
-                d = os.path.join(self.ProgramFiles, path)
-                if os.path.isdir(d):
+                path = r'Microsoft SDKs\Windows Kits\%s' % intver
+                d = join(self.ProgramFiles, path)
+                if isdir(d):
                     sdkdir = d
-        if not sdkdir or not os.path.isdir(sdkdir):
+        if not sdkdir or not isdir(sdkdir):
             # If fail, use default old path
             for ver in self.WindowsSdkVersion:
                 path = r'Microsoft SDKs\Windows\v%s' % ver
-                d = os.path.join(self.ProgramFiles, path)
-                if os.path.isdir(d):
+                d = join(self.ProgramFiles, path)
+                if isdir(d):
                     sdkdir = d
         if not sdkdir:
             # If fail, use Platform SDK
-            sdkdir = os.path.join(self.VCInstallDir, 'PlatformSDK')
+            sdkdir = join(self.VCInstallDir, 'PlatformSDK')
         return sdkdir
 
     @property
     def WindowsSDKExecutablePath(self):
         """
         Microsoft Windows SDK executable directory.
+
+        Return
+        ------
+        str
+            path
         """
         # Find WinSDK NetFx Tools registry dir name
-        if self.vc_ver <= 11.0:
+        if self.vs_ver <= 11.0:
             netfxver = 35
             arch = ''
         else:
             netfxver = 40
-            hidex86 = True if self.vc_ver <= 12.0 else False
+            hidex86 = True if self.vs_ver <= 12.0 else False
             arch = self.pi.current_dir(x64=True, hidex86=hidex86)
         fx = 'WinSDK-NetFx%dTools%s' % (netfxver, arch.replace('\\', '-'))
 
-        # liste all possibles registry paths
+        # list all possibles registry paths
         regpaths = []
-        if self.vc_ver >= 14.0:
+        if self.vs_ver >= 14.0:
             for ver in self.NetFxSdkVersion:
-                regpaths += [os.path.join(self.ri.netfx_sdk, ver, fx)]
+                regpaths += [join(self.ri.netfx_sdk, ver, fx)]
 
         for ver in self.WindowsSdkVersion:
-            regpaths += [os.path.join(self.ri.windows_sdk, 'v%sA' % ver, fx)]
+            regpaths += [join(self.ri.windows_sdk, 'v%sA' % ver, fx)]
 
         # Return installation folder from the more recent path
         for path in regpaths:
             execpath = self.ri.lookup(path, 'installationfolder')
             if execpath:
-                break
-        return execpath
+                return execpath
 
     @property
     def FSharpInstallDir(self):
         """
         Microsoft Visual F# directory.
+
+        Return
+        ------
+        str
+            path
         """
-        path = r'%0.1f\Setup\F#' % self.vc_ver
-        path = os.path.join(self.ri.visualstudio, path)
+        path = join(self.ri.visualstudio, r'%0.1f\Setup\F#' % self.vs_ver)
         return self.ri.lookup(path, 'productdir') or ''
 
     @property
     def UniversalCRTSdkDir(self):
         """
         Microsoft Universal CRT SDK directory.
+
+        Return
+        ------
+        str
+            path
         """
         # Set Kit Roots versions for specified MSVC++ version
-        if self.vc_ver >= 14.0:
-            vers = ('10', '81')
-        else:
-            vers = ()
+        vers = ('10', '81') if self.vs_ver >= 14.0 else ()
 
         # Find path of the more recent Kit
         for ver in vers:
             sdkdir = self.ri.lookup(self.ri.windows_kits_roots,
                                     'kitsroot%s' % ver)
             if sdkdir:
-                break
-        return sdkdir or ''
+                return sdkdir or ''
 
     @property
     def UniversalCRTSdkLastVersion(self):
         """
-        Microsoft Universal C Runtime SDK last version
+        Microsoft Universal C Runtime SDK last version.
+
+        Return
+        ------
+        str
+            version
         """
-        return self._use_last_dir_name(os.path.join(
-            self.UniversalCRTSdkDir, 'lib'))
+        return self._use_last_dir_name(join(self.UniversalCRTSdkDir, 'lib'))
 
     @property
     def NetFxSdkVersion(self):
         """
         Microsoft .NET Framework SDK versions.
+
+        Return
+        ------
+        tuple of str
+            versions
         """
-        # Set FxSdk versions for specified MSVC++ version
-        if self.vc_ver >= 14.0:
-            return ('4.6.1', '4.6')
-        else:
-            return ()
+        # Set FxSdk versions for specified VS version
+        return (('4.7.2', '4.7.1', '4.7',
+                 '4.6.2', '4.6.1', '4.6',
+                 '4.5.2', '4.5.1', '4.5')
+                if self.vs_ver >= 14.0 else ())
 
     @property
     def NetFxSdkDir(self):
         """
         Microsoft .NET Framework SDK directory.
+
+        Return
+        ------
+        str
+            path
         """
+        sdkdir = ''
         for ver in self.NetFxSdkVersion:
-            loc = os.path.join(self.ri.netfx_sdk, ver)
+            loc = join(self.ri.netfx_sdk, ver)
             sdkdir = self.ri.lookup(loc, 'kitsinstallationfolder')
             if sdkdir:
                 break
-        return sdkdir or ''
+        return sdkdir
 
     @property
     def FrameworkDir32(self):
         """
         Microsoft .NET Framework 32bit directory.
+
+        Return
+        ------
+        str
+            path
         """
         # Default path
-        guess_fw = os.path.join(self.WinDir, r'Microsoft.NET\Framework')
+        guess_fw = join(self.WinDir, r'Microsoft.NET\Framework')
 
         # Try to get path from registry, if fail use default path
         return self.ri.lookup(self.ri.vc, 'frameworkdir32') or guess_fw
@@ -746,9 +1097,14 @@ class SystemInfo:
     def FrameworkDir64(self):
         """
         Microsoft .NET Framework 64bit directory.
+
+        Return
+        ------
+        str
+            path
         """
         # Default path
-        guess_fw = os.path.join(self.WinDir, r'Microsoft.NET\Framework64')
+        guess_fw = join(self.WinDir, r'Microsoft.NET\Framework64')
 
         # Try to get path from registry, if fail use default path
         return self.ri.lookup(self.ri.vc, 'frameworkdir64') or guess_fw
@@ -757,6 +1113,11 @@ class SystemInfo:
     def FrameworkVersion32(self):
         """
         Microsoft .NET Framework 32bit versions.
+
+        Return
+        ------
+        tuple of str
+            versions
         """
         return self._find_dot_net_versions(32)
 
@@ -764,6 +1125,11 @@ class SystemInfo:
     def FrameworkVersion64(self):
         """
         Microsoft .NET Framework 64bit versions.
+
+        Return
+        ------
+        tuple of str
+            versions
         """
         return self._find_dot_net_versions(64)
 
@@ -775,6 +1141,11 @@ class SystemInfo:
         ----------
         bits: int
             Platform number of bits: 32 or 64.
+
+        Return
+        ------
+        tuple of str
+            versions
         """
         # Find actual .NET version in registry
         reg_ver = self.ri.lookup(self.ri.vc, 'frameworkver%d' % bits)
@@ -782,18 +1153,17 @@ class SystemInfo:
         ver = reg_ver or self._use_last_dir_name(dot_net_dir, 'v') or ''
 
         # Set .NET versions for specified MSVC++ version
-        if self.vc_ver >= 12.0:
-            frameworkver = (ver, 'v4.0')
-        elif self.vc_ver >= 10.0:
-            frameworkver = ('v4.0.30319' if ver.lower()[:2] != 'v4' else ver,
-                            'v3.5')
-        elif self.vc_ver == 9.0:
-            frameworkver = ('v3.5', 'v2.0.50727')
-        if self.vc_ver == 8.0:
-            frameworkver = ('v3.0', 'v2.0.50727')
-        return frameworkver
-
-    def _use_last_dir_name(self, path, prefix=''):
+        if self.vs_ver >= 12.0:
+            return ver, 'v4.0'
+        elif self.vs_ver >= 10.0:
+            return 'v4.0.30319' if ver.lower()[:2] != 'v4' else ver, 'v3.5'
+        elif self.vs_ver == 9.0:
+            return 'v3.5', 'v2.0.50727'
+        elif self.vs_ver == 8.0:
+            return 'v3.0', 'v2.0.50727'
+
+    @staticmethod
+    def _use_last_dir_name(path, prefix=''):
         """
         Return name of the last dir in path or '' if no dir found.
 
@@ -802,12 +1172,17 @@ class SystemInfo:
         path: str
             Use dirs in this path
         prefix: str
-            Use only dirs startings by this prefix
+            Use only dirs starting by this prefix
+
+        Return
+        ------
+        str
+            name
         """
         matching_dirs = (
             dir_name
-            for dir_name in reversed(os.listdir(path))
-            if os.path.isdir(os.path.join(path, dir_name)) and
+            for dir_name in reversed(listdir(path))
+            if isdir(join(path, dir_name)) and
             dir_name.startswith(prefix)
         )
         return next(matching_dirs, None) or ''
@@ -818,7 +1193,7 @@ class EnvironmentInfo:
     Return environment variables for specified Microsoft Visual C++ version
     and platform : Lib, Include, Path and libpath.
 
-    This function is compatible with Microsoft Visual C++ 9.0 to 14.0.
+    This function is compatible with Microsoft Visual C++ 9.0 to 14.X.
 
     Script created by analysing Microsoft environment configuration files like
     "vcvars[...].bat", "SetEnv.Cmd", "vcbuildtools.bat", ...
@@ -835,7 +1210,7 @@ class EnvironmentInfo:
     """
 
     # Variables and properties in this class use originals CamelCase variables
-    # names from Microsoft source files for more easy comparaison.
+    # names from Microsoft source files for more easy comparison.
 
     def __init__(self, arch, vc_ver=None, vc_min_ver=0):
         self.pi = PlatformInfo(arch)
@@ -847,204 +1222,257 @@ class EnvironmentInfo:
             raise distutils.errors.DistutilsPlatformError(err)
 
     @property
+    def vs_ver(self):
+        """
+        Microsoft Visual Studio.
+
+        Return
+        ------
+        float
+            version
+        """
+        return self.si.vs_ver
+
+    @property
     def vc_ver(self):
         """
         Microsoft Visual C++ version.
+
+        Return
+        ------
+        float
+            version
         """
         return self.si.vc_ver
 
     @property
     def VSTools(self):
         """
-        Microsoft Visual Studio Tools
+        Microsoft Visual Studio Tools.
+
+        Return
+        ------
+        list of str
+            paths
         """
         paths = [r'Common7\IDE', r'Common7\Tools']
 
-        if self.vc_ver >= 14.0:
+        if self.vs_ver >= 14.0:
             arch_subdir = self.pi.current_dir(hidex86=True, x64=True)
             paths += [r'Common7\IDE\CommonExtensions\Microsoft\TestWindow']
             paths += [r'Team Tools\Performance Tools']
             paths += [r'Team Tools\Performance Tools%s' % arch_subdir]
 
-        return [os.path.join(self.si.VSInstallDir, path) for path in paths]
+        return [join(self.si.VSInstallDir, path) for path in paths]
 
     @property
     def VCIncludes(self):
         """
-        Microsoft Visual C++ & Microsoft Foundation Class Includes
+        Microsoft Visual C++ & Microsoft Foundation Class Includes.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        return [os.path.join(self.si.VCInstallDir, 'Include'),
-                os.path.join(self.si.VCInstallDir, r'ATLMFC\Include')]
+        return [join(self.si.VCInstallDir, 'Include'),
+                join(self.si.VCInstallDir, r'ATLMFC\Include')]
 
     @property
     def VCLibraries(self):
         """
-        Microsoft Visual C++ & Microsoft Foundation Class Libraries
+        Microsoft Visual C++ & Microsoft Foundation Class Libraries.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver >= 15.0:
+        if self.vs_ver >= 15.0:
             arch_subdir = self.pi.target_dir(x64=True)
         else:
             arch_subdir = self.pi.target_dir(hidex86=True)
         paths = ['Lib%s' % arch_subdir, r'ATLMFC\Lib%s' % arch_subdir]
 
-        if self.vc_ver >= 14.0:
+        if self.vs_ver >= 14.0:
             paths += [r'Lib\store%s' % arch_subdir]
 
-        return [os.path.join(self.si.VCInstallDir, path) for path in paths]
+        return [join(self.si.VCInstallDir, path) for path in paths]
 
     @property
     def VCStoreRefs(self):
         """
-        Microsoft Visual C++ store references Libraries
+        Microsoft Visual C++ store references Libraries.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 14.0:
+        if self.vs_ver < 14.0:
             return []
-        return [os.path.join(self.si.VCInstallDir, r'Lib\store\references')]
+        return [join(self.si.VCInstallDir, r'Lib\store\references')]
 
     @property
     def VCTools(self):
         """
-        Microsoft Visual C++ Tools
+        Microsoft Visual C++ Tools.
+
+        Return
+        ------
+        list of str
+            paths
         """
         si = self.si
-        tools = [os.path.join(si.VCInstallDir, 'VCPackages')]
+        tools = [join(si.VCInstallDir, 'VCPackages')]
 
-        forcex86 = True if self.vc_ver <= 10.0 else False
+        forcex86 = True if self.vs_ver <= 10.0 else False
         arch_subdir = self.pi.cross_dir(forcex86)
         if arch_subdir:
-            tools += [os.path.join(si.VCInstallDir, 'Bin%s' % arch_subdir)]
+            tools += [join(si.VCInstallDir, 'Bin%s' % arch_subdir)]
 
-        if self.vc_ver == 14.0:
+        if self.vs_ver == 14.0:
             path = 'Bin%s' % self.pi.current_dir(hidex86=True)
-            tools += [os.path.join(si.VCInstallDir, path)]
+            tools += [join(si.VCInstallDir, path)]
 
-        elif self.vc_ver >= 15.0:
+        elif self.vs_ver >= 15.0:
             host_dir = (r'bin\HostX86%s' if self.pi.current_is_x86() else
                         r'bin\HostX64%s')
-            tools += [os.path.join(
+            tools += [join(
                 si.VCInstallDir, host_dir % self.pi.target_dir(x64=True))]
 
             if self.pi.current_cpu != self.pi.target_cpu:
-                tools += [os.path.join(
+                tools += [join(
                     si.VCInstallDir, host_dir % self.pi.current_dir(x64=True))]
 
         else:
-            tools += [os.path.join(si.VCInstallDir, 'Bin')]
+            tools += [join(si.VCInstallDir, 'Bin')]
 
         return tools
 
     @property
     def OSLibraries(self):
         """
-        Microsoft Windows SDK Libraries
+        Microsoft Windows SDK Libraries.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver <= 10.0:
+        if self.vs_ver <= 10.0:
             arch_subdir = self.pi.target_dir(hidex86=True, x64=True)
-            return [os.path.join(self.si.WindowsSdkDir, 'Lib%s' % arch_subdir)]
+            return [join(self.si.WindowsSdkDir, 'Lib%s' % arch_subdir)]
 
         else:
             arch_subdir = self.pi.target_dir(x64=True)
-            lib = os.path.join(self.si.WindowsSdkDir, 'lib')
+            lib = join(self.si.WindowsSdkDir, 'lib')
             libver = self._sdk_subdir
-            return [os.path.join(lib, '%sum%s' % (libver , arch_subdir))]
+            return [join(lib, '%sum%s' % (libver, arch_subdir))]
 
     @property
     def OSIncludes(self):
         """
-        Microsoft Windows SDK Include
+        Microsoft Windows SDK Include.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        include = os.path.join(self.si.WindowsSdkDir, 'include')
+        include = join(self.si.WindowsSdkDir, 'include')
 
-        if self.vc_ver <= 10.0:
-            return [include, os.path.join(include, 'gl')]
+        if self.vs_ver <= 10.0:
+            return [include, join(include, 'gl')]
 
         else:
-            if self.vc_ver >= 14.0:
+            if self.vs_ver >= 14.0:
                 sdkver = self._sdk_subdir
             else:
                 sdkver = ''
-            return [os.path.join(include, '%sshared' % sdkver),
-                    os.path.join(include, '%sum' % sdkver),
-                    os.path.join(include, '%swinrt' % sdkver)]
+            return [join(include, '%sshared' % sdkver),
+                    join(include, '%sum' % sdkver),
+                    join(include, '%swinrt' % sdkver)]
 
     @property
     def OSLibpath(self):
         """
-        Microsoft Windows SDK Libraries Paths
+        Microsoft Windows SDK Libraries Paths.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        ref = os.path.join(self.si.WindowsSdkDir, 'References')
+        ref = join(self.si.WindowsSdkDir, 'References')
         libpath = []
 
-        if self.vc_ver <= 9.0:
+        if self.vs_ver <= 9.0:
             libpath += self.OSLibraries
 
-        if self.vc_ver >= 11.0:
-            libpath += [os.path.join(ref, r'CommonConfiguration\Neutral')]
+        if self.vs_ver >= 11.0:
+            libpath += [join(ref, r'CommonConfiguration\Neutral')]
 
-        if self.vc_ver >= 14.0:
+        if self.vs_ver >= 14.0:
             libpath += [
                 ref,
-                os.path.join(self.si.WindowsSdkDir, 'UnionMetadata'),
-                os.path.join(
-                    ref,
-                    'Windows.Foundation.UniversalApiContract',
-                    '1.0.0.0',
-                ),
-                os.path.join(
-                    ref,
-                    'Windows.Foundation.FoundationContract',
-                    '1.0.0.0',
-                ),
-                os.path.join(
-                    ref,
-                    'Windows.Networking.Connectivity.WwanContract',
-                    '1.0.0.0',
-                ),
-                os.path.join(
-                    self.si.WindowsSdkDir,
-                    'ExtensionSDKs',
-                    'Microsoft.VCLibs',
-                    '%0.1f' % self.vc_ver,
-                    'References',
-                    'CommonConfiguration',
-                    'neutral',
-                ),
+                join(self.si.WindowsSdkDir, 'UnionMetadata'),
+                join(
+                    ref, 'Windows.Foundation.UniversalApiContract', '1.0.0.0'),
+                join(ref, 'Windows.Foundation.FoundationContract', '1.0.0.0'),
+                join(
+                    ref, 'Windows.Networking.Connectivity.WwanContract',
+                    '1.0.0.0'),
+                join(
+                    self.si.WindowsSdkDir, 'ExtensionSDKs', 'Microsoft.VCLibs',
+                    '%0.1f' % self.vs_ver, 'References', 'CommonConfiguration',
+                    'neutral'),
             ]
         return libpath
 
     @property
     def SdkTools(self):
         """
-        Microsoft Windows SDK Tools
+        Microsoft Windows SDK Tools.
+
+        Return
+        ------
+        list of str
+            paths
         """
         return list(self._sdk_tools())
 
     def _sdk_tools(self):
         """
-        Microsoft Windows SDK Tools paths generator
+        Microsoft Windows SDK Tools paths generator.
+
+        Return
+        ------
+        generator of str
+            paths
         """
-        if self.vc_ver < 15.0:
-            bin_dir = 'Bin' if self.vc_ver <= 11.0 else r'Bin\x86'
-            yield os.path.join(self.si.WindowsSdkDir, bin_dir)
+        if self.vs_ver < 15.0:
+            bin_dir = 'Bin' if self.vs_ver <= 11.0 else r'Bin\x86'
+            yield join(self.si.WindowsSdkDir, bin_dir)
 
         if not self.pi.current_is_x86():
             arch_subdir = self.pi.current_dir(x64=True)
             path = 'Bin%s' % arch_subdir
-            yield os.path.join(self.si.WindowsSdkDir, path)
+            yield join(self.si.WindowsSdkDir, path)
 
-        if self.vc_ver == 10.0 or self.vc_ver == 11.0:
+        if self.vs_ver in (10.0, 11.0):
             if self.pi.target_is_x86():
                 arch_subdir = ''
             else:
                 arch_subdir = self.pi.current_dir(hidex86=True, x64=True)
             path = r'Bin\NETFX 4.0 Tools%s' % arch_subdir
-            yield os.path.join(self.si.WindowsSdkDir, path)
+            yield join(self.si.WindowsSdkDir, path)
 
-        elif self.vc_ver >= 15.0:
-            path = os.path.join(self.si.WindowsSdkDir, 'Bin')
+        elif self.vs_ver >= 15.0:
+            path = join(self.si.WindowsSdkDir, 'Bin')
             arch_subdir = self.pi.current_dir(x64=True)
             sdkver = self.si.WindowsSdkLastVersion
-            yield os.path.join(path, '%s%s' % (sdkver, arch_subdir))
+            yield join(path, '%s%s' % (sdkver, arch_subdir))
 
         if self.si.WindowsSDKExecutablePath:
             yield self.si.WindowsSDKExecutablePath
@@ -1052,7 +1480,12 @@ class EnvironmentInfo:
     @property
     def _sdk_subdir(self):
         """
-        Microsoft Windows SDK version subdir
+        Microsoft Windows SDK version subdir.
+
+        Return
+        ------
+        str
+            subdir
         """
         ucrtver = self.si.WindowsSdkLastVersion
         return ('%s\\' % ucrtver) if ucrtver else ''
@@ -1060,22 +1493,32 @@ class EnvironmentInfo:
     @property
     def SdkSetup(self):
         """
-        Microsoft Windows SDK Setup
+        Microsoft Windows SDK Setup.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver > 9.0:
+        if self.vs_ver > 9.0:
             return []
 
-        return [os.path.join(self.si.WindowsSdkDir, 'Setup')]
+        return [join(self.si.WindowsSdkDir, 'Setup')]
 
     @property
     def FxTools(self):
         """
-        Microsoft .NET Framework Tools
+        Microsoft .NET Framework Tools.
+
+        Return
+        ------
+        list of str
+            paths
         """
         pi = self.pi
         si = self.si
 
-        if self.vc_ver <= 10.0:
+        if self.vs_ver <= 10.0:
             include32 = True
             include64 = not pi.target_is_x86() and not pi.current_is_x86()
         else:
@@ -1084,102 +1527,142 @@ class EnvironmentInfo:
 
         tools = []
         if include32:
-            tools += [os.path.join(si.FrameworkDir32, ver)
+            tools += [join(si.FrameworkDir32, ver)
                       for ver in si.FrameworkVersion32]
         if include64:
-            tools += [os.path.join(si.FrameworkDir64, ver)
+            tools += [join(si.FrameworkDir64, ver)
                       for ver in si.FrameworkVersion64]
         return tools
 
     @property
     def NetFxSDKLibraries(self):
         """
-        Microsoft .Net Framework SDK Libraries
+        Microsoft .Net Framework SDK Libraries.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 14.0 or not self.si.NetFxSdkDir:
+        if self.vs_ver < 14.0 or not self.si.NetFxSdkDir:
             return []
 
         arch_subdir = self.pi.target_dir(x64=True)
-        return [os.path.join(self.si.NetFxSdkDir, r'lib\um%s' % arch_subdir)]
+        return [join(self.si.NetFxSdkDir, r'lib\um%s' % arch_subdir)]
 
     @property
     def NetFxSDKIncludes(self):
         """
-        Microsoft .Net Framework SDK Includes
+        Microsoft .Net Framework SDK Includes.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 14.0 or not self.si.NetFxSdkDir:
+        if self.vs_ver < 14.0 or not self.si.NetFxSdkDir:
             return []
 
-        return [os.path.join(self.si.NetFxSdkDir, r'include\um')]
+        return [join(self.si.NetFxSdkDir, r'include\um')]
 
     @property
     def VsTDb(self):
         """
-        Microsoft Visual Studio Team System Database
+        Microsoft Visual Studio Team System Database.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        return [os.path.join(self.si.VSInstallDir, r'VSTSDB\Deploy')]
+        return [join(self.si.VSInstallDir, r'VSTSDB\Deploy')]
 
     @property
     def MSBuild(self):
         """
-        Microsoft Build Engine
+        Microsoft Build Engine.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 12.0:
+        if self.vs_ver < 12.0:
             return []
-        elif self.vc_ver < 15.0:
+        elif self.vs_ver < 15.0:
             base_path = self.si.ProgramFilesx86
             arch_subdir = self.pi.current_dir(hidex86=True)
         else:
             base_path = self.si.VSInstallDir
             arch_subdir = ''
 
-        path = r'MSBuild\%0.1f\bin%s' % (self.vc_ver, arch_subdir)
-        build = [os.path.join(base_path, path)]
+        path = r'MSBuild\%0.1f\bin%s' % (self.vs_ver, arch_subdir)
+        build = [join(base_path, path)]
 
-        if self.vc_ver >= 15.0:
+        if self.vs_ver >= 15.0:
             # Add Roslyn C# & Visual Basic Compiler
-            build += [os.path.join(base_path, path, 'Roslyn')]
+            build += [join(base_path, path, 'Roslyn')]
 
         return build
 
     @property
     def HTMLHelpWorkshop(self):
         """
-        Microsoft HTML Help Workshop
+        Microsoft HTML Help Workshop.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 11.0:
+        if self.vs_ver < 11.0:
             return []
 
-        return [os.path.join(self.si.ProgramFilesx86, 'HTML Help Workshop')]
+        return [join(self.si.ProgramFilesx86, 'HTML Help Workshop')]
 
     @property
     def UCRTLibraries(self):
         """
-        Microsoft Universal C Runtime SDK Libraries
+        Microsoft Universal C Runtime SDK Libraries.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 14.0:
+        if self.vs_ver < 14.0:
             return []
 
         arch_subdir = self.pi.target_dir(x64=True)
-        lib = os.path.join(self.si.UniversalCRTSdkDir, 'lib')
+        lib = join(self.si.UniversalCRTSdkDir, 'lib')
         ucrtver = self._ucrt_subdir
-        return [os.path.join(lib, '%sucrt%s' % (ucrtver, arch_subdir))]
+        return [join(lib, '%sucrt%s' % (ucrtver, arch_subdir))]
 
     @property
     def UCRTIncludes(self):
         """
-        Microsoft Universal C Runtime SDK Include
+        Microsoft Universal C Runtime SDK Include.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 14.0:
+        if self.vs_ver < 14.0:
             return []
 
-        include = os.path.join(self.si.UniversalCRTSdkDir, 'include')
-        return [os.path.join(include, '%sucrt' % self._ucrt_subdir)]
+        include = join(self.si.UniversalCRTSdkDir, 'include')
+        return [join(include, '%sucrt' % self._ucrt_subdir)]
 
     @property
     def _ucrt_subdir(self):
         """
-        Microsoft Universal C Runtime SDK version subdir
+        Microsoft Universal C Runtime SDK version subdir.
+
+        Return
+        ------
+        str
+            subdir
         """
         ucrtver = self.si.UniversalCRTSdkLastVersion
         return ('%s\\' % ucrtver) if ucrtver else ''
@@ -1187,31 +1670,52 @@ class EnvironmentInfo:
     @property
     def FSharp(self):
         """
-        Microsoft Visual F#
+        Microsoft Visual F#.
+
+        Return
+        ------
+        list of str
+            paths
         """
-        if self.vc_ver < 11.0 and self.vc_ver > 12.0:
+        if 11.0 > self.vs_ver > 12.0:
             return []
 
-        return self.si.FSharpInstallDir
+        return [self.si.FSharpInstallDir]
 
     @property
     def VCRuntimeRedist(self):
         """
-        Microsoft Visual C++ runtime redistribuable dll
-        """
-        arch_subdir = self.pi.target_dir(x64=True)
-        if self.vc_ver < 15:
-            redist_path = self.si.VCInstallDir
-            vcruntime = 'redist%s\\Microsoft.VC%d0.CRT\\vcruntime%d0.dll'
-        else:
-            redist_path = self.si.VCInstallDir.replace('\\Tools', '\\Redist')
-            vcruntime = 'onecore%s\\Microsoft.VC%d0.CRT\\vcruntime%d0.dll'
+        Microsoft Visual C++ runtime redistributable dll.
 
-        # Visual Studio 2017  is still Visual C++ 14.0
-        dll_ver = 14.0 if self.vc_ver == 15 else self.vc_ver
-
-        vcruntime = vcruntime % (arch_subdir, self.vc_ver, dll_ver)
-        return os.path.join(redist_path, vcruntime)
+        Return
+        ------
+        str
+            path
+        """
+        vcruntime = 'vcruntime%d0.dll' % self.vc_ver
+        arch_subdir = self.pi.target_dir(x64=True).strip('\\')
+
+        # Installation prefixes candidates
+        prefixes = []
+        tools_path = self.si.VCInstallDir
+        redist_path = dirname(tools_path.replace(r'\Tools', r'\Redist'))
+        if isdir(redist_path):
+            # Redist version may not be exactly the same as tools
+            redist_path = join(redist_path, listdir(redist_path)[-1])
+            prefixes += [redist_path, join(redist_path, 'onecore')]
+
+        prefixes += [join(tools_path, 'redist')]  # VS14 legacy path
+
+        # CRT directory
+        crt_dirs = ('Microsoft.VC%d.CRT' % (self.vc_ver * 10),
+                    # Sometime store in directory with VS version instead of VC
+                    'Microsoft.VC%d.CRT' % (int(self.vs_ver) * 10))
+
+        # vcruntime path
+        for prefix, crt_dir in itertools.product(prefixes, crt_dirs):
+            path = join(prefix, arch_subdir, crt_dir, vcruntime)
+            if isfile(path):
+                return path
 
     def return_env(self, exists=True):
         """
@@ -1221,6 +1725,11 @@ class EnvironmentInfo:
         ----------
         exists: bool
             It True, only return existing paths.
+
+        Return
+        ------
+        dict
+            environment
         """
         env = dict(
             include=self._build_paths('include',
@@ -1254,7 +1763,7 @@ class EnvironmentInfo:
                                     self.FSharp],
                                    exists),
         )
-        if self.vc_ver >= 14 and os.path.isfile(self.VCRuntimeRedist):
+        if self.vs_ver >= 14 and isfile(self.VCRuntimeRedist):
             env['py_vcruntime_redist'] = self.VCRuntimeRedist
         return env
 
@@ -1265,20 +1774,35 @@ class EnvironmentInfo:
         unique, extant, directories from those paths and from
         the environment variable. Raise an error if no paths
         are resolved.
+
+        Parameters
+        ----------
+        name: str
+            Environment variable name
+        spec_path_lists: list of str
+            Paths
+        exists: bool
+            It True, only return existing paths.
+
+        Return
+        ------
+        str
+            Pathsep-separated paths
         """
         # flatten spec_path_lists
         spec_paths = itertools.chain.from_iterable(spec_path_lists)
-        env_paths = safe_env.get(name, '').split(os.pathsep)
+        env_paths = environ.get(name, '').split(pathsep)
         paths = itertools.chain(spec_paths, env_paths)
-        extant_paths = list(filter(os.path.isdir, paths)) if exists else paths
+        extant_paths = list(filter(isdir, paths)) if exists else paths
         if not extant_paths:
             msg = "%s environment variable is empty" % name.upper()
             raise distutils.errors.DistutilsPlatformError(msg)
         unique_paths = self._unique_everseen(extant_paths)
-        return os.pathsep.join(unique_paths)
+        return pathsep.join(unique_paths)
 
     # from Python docs
-    def _unique_everseen(self, iterable, key=None):
+    @staticmethod
+    def _unique_everseen(iterable, key=None):
         """
         List unique elements, preserving order.
         Remember all elements ever seen.
diff --git a/setuptools/namespaces.py b/setuptools/namespaces.py
index dc16106d..5f403c96 100644
--- a/setuptools/namespaces.py
+++ b/setuptools/namespaces.py
@@ -47,13 +47,17 @@ class Installer:
         "p = os.path.join(%(root)s, *%(pth)r)",
         "importlib = has_mfs and __import__('importlib.util')",
         "has_mfs and __import__('importlib.machinery')",
-        "m = has_mfs and "
+        (
+            "m = has_mfs and "
             "sys.modules.setdefault(%(pkg)r, "
-                "importlib.util.module_from_spec("
-                    "importlib.machinery.PathFinder.find_spec(%(pkg)r, "
-                        "[os.path.dirname(p)])))",
-        "m = m or "
-            "sys.modules.setdefault(%(pkg)r, types.ModuleType(%(pkg)r))",
+            "importlib.util.module_from_spec("
+            "importlib.machinery.PathFinder.find_spec(%(pkg)r, "
+            "[os.path.dirname(p)])))"
+        ),
+        (
+            "m = m or "
+            "sys.modules.setdefault(%(pkg)r, types.ModuleType(%(pkg)r))"
+        ),
         "mp = (m or []) and m.__dict__.setdefault('__path__',[])",
         "(p not in mp) and mp.append(p)",
     )
diff --git a/setuptools/package_index.py b/setuptools/package_index.py
index 6b06f2ca..0744ea2a 100644
--- a/setuptools/package_index.py
+++ b/setuptools/package_index.py
@@ -46,7 +46,8 @@ __all__ = [
 _SOCKET_TIMEOUT = 15
 
 _tmpl = "setuptools/{setuptools.__version__} Python-urllib/{py_major}"
-user_agent = _tmpl.format(py_major=sys.version[:3], setuptools=setuptools)
+user_agent = _tmpl.format(
+    py_major='{}.{}'.format(*sys.version_info), setuptools=setuptools)
 
 
 def parse_requirement_arg(spec):
@@ -348,6 +349,8 @@ class PackageIndex(Environment):
         f = self.open_url(url, tmpl % url)
         if f is None:
             return
+        if isinstance(f, urllib.error.HTTPError) and f.code == 401:
+            self.info("Authentication error: %s" % f.msg)
         self.fetched_urls[f.url] = True
         if 'html' not in f.headers.get('content-type', '').lower():
             f.close()  # not html, we can't process it
@@ -1050,7 +1053,7 @@ def open_with_auth(url, opener=urllib.request.urlopen):
     parsed = urllib.parse.urlparse(url)
     scheme, netloc, path, params, query, frag = parsed
 
-    # Double scheme does not raise on Mac OS X as revealed by a
+    # Double scheme does not raise on macOS as revealed by a
     # failing test. We would expect "nonnumeric port". Refs #20.
     if netloc.endswith(':'):
         raise http_client.InvalidURL("nonnumeric port: ''")
@@ -1092,7 +1095,8 @@ def open_with_auth(url, opener=urllib.request.urlopen):
 
 # copy of urllib.parse._splituser from Python 3.8
 def _splituser(host):
-    """splituser('user[:passwd]@host[:port]') --> 'user[:passwd]', 'host[:port]'."""
+    """splituser('user[:passwd]@host[:port]')
+    --> 'user[:passwd]', 'host[:port]'."""
     user, delim, host = host.rpartition('@')
     return (user if delim else None), host
 
diff --git a/setuptools/pep425tags.py b/setuptools/pep425tags.py
deleted file mode 100644
index 48745a29..00000000
--- a/setuptools/pep425tags.py
+++ /dev/null
@@ -1,319 +0,0 @@
-# This file originally from pip:
-# https://github.com/pypa/pip/blob/8f4f15a5a95d7d5b511ceaee9ed261176c181970/src/pip/_internal/pep425tags.py
-"""Generate and work with PEP 425 Compatibility Tags."""
-from __future__ import absolute_import
-
-import distutils.util
-from distutils import log
-import platform
-import re
-import sys
-import sysconfig
-import warnings
-from collections import OrderedDict
-
-from .extern import six
-
-from . import glibc
-
-_osx_arch_pat = re.compile(r'(.+)_(\d+)_(\d+)_(.+)')
-
-
-def get_config_var(var):
-    try:
-        return sysconfig.get_config_var(var)
-    except IOError as e:  # Issue #1074
-        warnings.warn("{}".format(e), RuntimeWarning)
-        return None
-
-
-def get_abbr_impl():
-    """Return abbreviated implementation name."""
-    if hasattr(sys, 'pypy_version_info'):
-        pyimpl = 'pp'
-    elif sys.platform.startswith('java'):
-        pyimpl = 'jy'
-    elif sys.platform == 'cli':
-        pyimpl = 'ip'
-    else:
-        pyimpl = 'cp'
-    return pyimpl
-
-
-def get_impl_ver():
-    """Return implementation version."""
-    impl_ver = get_config_var("py_version_nodot")
-    if not impl_ver or get_abbr_impl() == 'pp':
-        impl_ver = ''.join(map(str, get_impl_version_info()))
-    return impl_ver
-
-
-def get_impl_version_info():
-    """Return sys.version_info-like tuple for use in decrementing the minor
-    version."""
-    if get_abbr_impl() == 'pp':
-        # as per https://github.com/pypa/pip/issues/2882
-        return (sys.version_info[0], sys.pypy_version_info.major,
-                sys.pypy_version_info.minor)
-    else:
-        return sys.version_info[0], sys.version_info[1]
-
-
-def get_impl_tag():
-    """
-    Returns the Tag for this specific implementation.
-    """
-    return "{}{}".format(get_abbr_impl(), get_impl_ver())
-
-
-def get_flag(var, fallback, expected=True, warn=True):
-    """Use a fallback method for determining SOABI flags if the needed config
-    var is unset or unavailable."""
-    val = get_config_var(var)
-    if val is None:
-        if warn:
-            log.debug("Config variable '%s' is unset, Python ABI tag may "
-                      "be incorrect", var)
-        return fallback()
-    return val == expected
-
-
-def get_abi_tag():
-    """Return the ABI tag based on SOABI (if available) or emulate SOABI
-    (CPython 2, PyPy)."""
-    soabi = get_config_var('SOABI')
-    impl = get_abbr_impl()
-    if not soabi and impl in {'cp', 'pp'} and hasattr(sys, 'maxunicode'):
-        d = ''
-        m = ''
-        u = ''
-        if get_flag('Py_DEBUG',
-                    lambda: hasattr(sys, 'gettotalrefcount'),
-                    warn=(impl == 'cp')):
-            d = 'd'
-        if get_flag('WITH_PYMALLOC',
-                    lambda: impl == 'cp',
-                    warn=(impl == 'cp')):
-            m = 'm'
-        if get_flag('Py_UNICODE_SIZE',
-                    lambda: sys.maxunicode == 0x10ffff,
-                    expected=4,
-                    warn=(impl == 'cp' and
-                          six.PY2)) \
-                and six.PY2:
-            u = 'u'
-        abi = '%s%s%s%s%s' % (impl, get_impl_ver(), d, m, u)
-    elif soabi and soabi.startswith('cpython-'):
-        abi = 'cp' + soabi.split('-')[1]
-    elif soabi:
-        abi = soabi.replace('.', '_').replace('-', '_')
-    else:
-        abi = None
-    return abi
-
-
-def _is_running_32bit():
-    return sys.maxsize == 2147483647
-
-
-def get_platform():
-    """Return our platform name 'win32', 'linux_x86_64'"""
-    if sys.platform == 'darwin':
-        # distutils.util.get_platform() returns the release based on the value
-        # of MACOSX_DEPLOYMENT_TARGET on which Python was built, which may
-        # be significantly older than the user's current machine.
-        release, _, machine = platform.mac_ver()
-        split_ver = release.split('.')
-
-        if machine == "x86_64" and _is_running_32bit():
-            machine = "i386"
-        elif machine == "ppc64" and _is_running_32bit():
-            machine = "ppc"
-
-        return 'macosx_{}_{}_{}'.format(split_ver[0], split_ver[1], machine)
-
-    # XXX remove distutils dependency
-    result = distutils.util.get_platform().replace('.', '_').replace('-', '_')
-    if result == "linux_x86_64" and _is_running_32bit():
-        # 32 bit Python program (running on a 64 bit Linux): pip should only
-        # install and run 32 bit compiled extensions in that case.
-        result = "linux_i686"
-
-    return result
-
-
-def is_manylinux1_compatible():
-    # Only Linux, and only x86-64 / i686
-    if get_platform() not in {"linux_x86_64", "linux_i686"}:
-        return False
-
-    # Check for presence of _manylinux module
-    try:
-        import _manylinux
-        return bool(_manylinux.manylinux1_compatible)
-    except (ImportError, AttributeError):
-        # Fall through to heuristic check below
-        pass
-
-    # Check glibc version. CentOS 5 uses glibc 2.5.
-    return glibc.have_compatible_glibc(2, 5)
-
-
-def get_darwin_arches(major, minor, machine):
-    """Return a list of supported arches (including group arches) for
-    the given major, minor and machine architecture of a macOS machine.
-    """
-    arches = []
-
-    def _supports_arch(major, minor, arch):
-        # Looking at the application support for macOS versions in the chart
-        # provided by https://en.wikipedia.org/wiki/OS_X#Versions it appears
-        # our timeline looks roughly like:
-        #
-        # 10.0 - Introduces ppc support.
-        # 10.4 - Introduces ppc64, i386, and x86_64 support, however the ppc64
-        #        and x86_64 support is CLI only, and cannot be used for GUI
-        #        applications.
-        # 10.5 - Extends ppc64 and x86_64 support to cover GUI applications.
-        # 10.6 - Drops support for ppc64
-        # 10.7 - Drops support for ppc
-        #
-        # Given that we do not know if we're installing a CLI or a GUI
-        # application, we must be conservative and assume it might be a GUI
-        # application and behave as if ppc64 and x86_64 support did not occur
-        # until 10.5.
-        #
-        # Note: The above information is taken from the "Application support"
-        #       column in the chart not the "Processor support" since I believe
-        #       that we care about what instruction sets an application can use
-        #       not which processors the OS supports.
-        if arch == 'ppc':
-            return (major, minor) <= (10, 5)
-        if arch == 'ppc64':
-            return (major, minor) == (10, 5)
-        if arch == 'i386':
-            return (major, minor) >= (10, 4)
-        if arch == 'x86_64':
-            return (major, minor) >= (10, 5)
-        if arch in groups:
-            for garch in groups[arch]:
-                if _supports_arch(major, minor, garch):
-                    return True
-        return False
-
-    groups = OrderedDict([
-        ("fat", ("i386", "ppc")),
-        ("intel", ("x86_64", "i386")),
-        ("fat64", ("x86_64", "ppc64")),
-        ("fat32", ("x86_64", "i386", "ppc")),
-    ])
-
-    if _supports_arch(major, minor, machine):
-        arches.append(machine)
-
-    for garch in groups:
-        if machine in groups[garch] and _supports_arch(major, minor, garch):
-            arches.append(garch)
-
-    arches.append('universal')
-
-    return arches
-
-
-def get_supported(versions=None, noarch=False, platform=None,
-                  impl=None, abi=None):
-    """Return a list of supported tags for each version specified in
-    `versions`.
-
-    :param versions: a list of string versions, of the form ["33", "32"],
-        or None. The first version will be assumed to support our ABI.
-    :param platform: specify the exact platform you want valid
-        tags for, or None. If None, use the local system platform.
-    :param impl: specify the exact implementation you want valid
-        tags for, or None. If None, use the local interpreter impl.
-    :param abi: specify the exact abi you want valid
-        tags for, or None. If None, use the local interpreter abi.
-    """
-    supported = []
-
-    # Versions must be given with respect to the preference
-    if versions is None:
-        versions = []
-        version_info = get_impl_version_info()
-        major = version_info[:-1]
-        # Support all previous minor Python versions.
-        for minor in range(version_info[-1], -1, -1):
-            versions.append(''.join(map(str, major + (minor,))))
-
-    impl = impl or get_abbr_impl()
-
-    abis = []
-
-    abi = abi or get_abi_tag()
-    if abi:
-        abis[0:0] = [abi]
-
-    abi3s = set()
-    import imp
-    for suffix in imp.get_suffixes():
-        if suffix[0].startswith('.abi'):
-            abi3s.add(suffix[0].split('.', 2)[1])
-
-    abis.extend(sorted(list(abi3s)))
-
-    abis.append('none')
-
-    if not noarch:
-        arch = platform or get_platform()
-        if arch.startswith('macosx'):
-            # support macosx-10.6-intel on macosx-10.9-x86_64
-            match = _osx_arch_pat.match(arch)
-            if match:
-                name, major, minor, actual_arch = match.groups()
-                tpl = '{}_{}_%i_%s'.format(name, major)
-                arches = []
-                for m in reversed(range(int(minor) + 1)):
-                    for a in get_darwin_arches(int(major), m, actual_arch):
-                        arches.append(tpl % (m, a))
-            else:
-                # arch pattern didn't match (?!)
-                arches = [arch]
-        elif platform is None and is_manylinux1_compatible():
-            arches = [arch.replace('linux', 'manylinux1'), arch]
-        else:
-            arches = [arch]
-
-        # Current version, current API (built specifically for our Python):
-        for abi in abis:
-            for arch in arches:
-                supported.append(('%s%s' % (impl, versions[0]), abi, arch))
-
-        # abi3 modules compatible with older version of Python
-        for version in versions[1:]:
-            # abi3 was introduced in Python 3.2
-            if version in {'31', '30'}:
-                break
-            for abi in abi3s:   # empty set if not Python 3
-                for arch in arches:
-                    supported.append(("%s%s" % (impl, version), abi, arch))
-
-        # Has binaries, does not use the Python API:
-        for arch in arches:
-            supported.append(('py%s' % (versions[0][0]), 'none', arch))
-
-    # No abi / arch, but requires our implementation:
-    supported.append(('%s%s' % (impl, versions[0]), 'none', 'any'))
-    # Tagged specifically as being cross-version compatible
-    # (with just the major version specified)
-    supported.append(('%s%s' % (impl, versions[0][0]), 'none', 'any'))
-
-    # No abi / arch, generic Python
-    for i, version in enumerate(versions):
-        supported.append(('py%s' % (version,), 'none', 'any'))
-        if i == 0:
-            supported.append(('py%s' % (version[0]), 'none', 'any'))
-
-    return supported
-
-
-implementation_tag = get_impl_tag()
diff --git a/setuptools/py27compat.py b/setuptools/py27compat.py
index 2985011b..ba39af52 100644
--- a/setuptools/py27compat.py
+++ b/setuptools/py27compat.py
@@ -2,6 +2,7 @@
 Compatibility Support for Python 2.7 and earlier
 """
 
+import sys
 import platform
 
 from setuptools.extern import six
@@ -15,7 +16,7 @@ def get_all_headers(message, key):
 
 
 if six.PY2:
-    def get_all_headers(message, key):
+    def get_all_headers(message, key):  # noqa
         return message.getheaders(key)
 
 
@@ -26,3 +27,34 @@ linux_py2_ascii = (
 
 rmtree_safe = str if linux_py2_ascii else lambda x: x
 """Workaround for http://bugs.python.org/issue24672"""
+
+
+try:
+    from ._imp import find_module, PY_COMPILED, PY_FROZEN, PY_SOURCE
+    from ._imp import get_frozen_object, get_module
+except ImportError:
+    import imp
+    from imp import PY_COMPILED, PY_FROZEN, PY_SOURCE  # noqa
+
+    def find_module(module, paths=None):
+        """Just like 'imp.find_module()', but with package support"""
+        parts = module.split('.')
+        while parts:
+            part = parts.pop(0)
+            f, path, (suffix, mode, kind) = info = imp.find_module(part, paths)
+
+            if kind == imp.PKG_DIRECTORY:
+                parts = parts or ['__init__']
+                paths = [path]
+
+            elif parts:
+                raise ImportError("Can't find %r in %s" % (parts, module))
+
+        return info
+
+    def get_frozen_object(module, paths):
+        return imp.get_frozen_object(module)
+
+    def get_module(module, paths, info):
+        imp.load_module(module, *info)
+        return sys.modules[module]
diff --git a/setuptools/py34compat.py b/setuptools/py34compat.py
new file mode 100644
index 00000000..3ad91722
--- /dev/null
+++ b/setuptools/py34compat.py
@@ -0,0 +1,13 @@
+import importlib
+
+try:
+    import importlib.util
+except ImportError:
+    pass
+
+
+try:
+    module_from_spec = importlib.util.module_from_spec
+except AttributeError:
+    def module_from_spec(spec):
+        return spec.loader.load_module(spec.name)
diff --git a/setuptools/sandbox.py b/setuptools/sandbox.py
index 685f3f72..e46dfc8d 100644
--- a/setuptools/sandbox.py
+++ b/setuptools/sandbox.py
@@ -13,6 +13,8 @@ from setuptools.extern import six
 from setuptools.extern.six.moves import builtins, map
 
 import pkg_resources.py31compat
+from distutils.errors import DistutilsError
+from pkg_resources import working_set
 
 if sys.platform.startswith('java'):
     import org.python.modules.posix.PosixModule as _os
@@ -23,8 +25,6 @@ try:
 except NameError:
     _file = None
 _open = open
-from distutils.errors import DistutilsError
-from pkg_resources import working_set
 
 
 __all__ = [
@@ -374,7 +374,7 @@ class AbstractSandbox:
 
 
 if hasattr(os, 'devnull'):
-    _EXCEPTIONS = [os.devnull,]
+    _EXCEPTIONS = [os.devnull]
 else:
     _EXCEPTIONS = []
 
@@ -466,7 +466,8 @@ class DirectorySandbox(AbstractSandbox):
 
 
 WRITE_FLAGS = functools.reduce(
-    operator.or_, [getattr(_os, a, 0) for a in
+    operator.or_, [
+        getattr(_os, a, 0) for a in
         "O_WRONLY O_RDWR O_APPEND O_CREAT O_TRUNC O_TEMPORARY".split()]
 )
 
diff --git a/setuptools/site-patch.py b/setuptools/site-patch.py
index 40b00de0..be0d43d3 100644
--- a/setuptools/site-patch.py
+++ b/setuptools/site-patch.py
@@ -38,22 +38,24 @@ def __boot():
     else:
         raise ImportError("Couldn't find the real 'site' module")
 
-    known_paths = dict([(makepath(item)[1], 1) for item in sys.path])  # 2.2 comp
+    # 2.2 comp
+    known_paths = dict([(
+        makepath(item)[1], 1) for item in sys.path])  # noqa
 
     oldpos = getattr(sys, '__egginsert', 0)  # save old insertion position
     sys.__egginsert = 0  # and reset the current one
 
     for item in PYTHONPATH:
-        addsitedir(item)
+        addsitedir(item)  # noqa
 
     sys.__egginsert += oldpos  # restore effective old position
 
-    d, nd = makepath(stdpath[0])
+    d, nd = makepath(stdpath[0])  # noqa
     insert_at = None
     new_path = []
 
     for item in sys.path:
-        p, np = makepath(item)
+        p, np = makepath(item)  # noqa
 
         if np == nd and insert_at is None:
             # We've hit the first 'system' path entry, so added entries go here
diff --git a/setuptools/ssl_support.py b/setuptools/ssl_support.py
index 226db694..17c14c46 100644
--- a/setuptools/ssl_support.py
+++ b/setuptools/ssl_support.py
@@ -35,7 +35,8 @@ try:
 except AttributeError:
     HTTPSHandler = HTTPSConnection = object
 
-is_available = ssl is not None and object not in (HTTPSHandler, HTTPSConnection)
+is_available = ssl is not None and object not in (
+    HTTPSHandler, HTTPSConnection)
 
 
 try:
@@ -85,8 +86,10 @@ if not match_hostname:
             return dn.lower() == hostname.lower()
 
         # RFC 6125, section 6.4.3, subitem 1.
-        # The client SHOULD NOT attempt to match a presented identifier in which
-        # the wildcard character comprises a label other than the left-most label.
+        # The client SHOULD NOT attempt to match a
+        # presented identifier in which the wildcard
+        # character comprises a label other than the
+        # left-most label.
         if leftmost == '*':
             # When '*' is a fragment by itself, it matches a non-empty dotless
             # fragment.
@@ -137,15 +140,16 @@ if not match_hostname:
                             return
                         dnsnames.append(value)
         if len(dnsnames) > 1:
-            raise CertificateError("hostname %r "
-                "doesn't match either of %s"
+            raise CertificateError(
+                "hostname %r doesn't match either of %s"
                 % (hostname, ', '.join(map(repr, dnsnames))))
         elif len(dnsnames) == 1:
-            raise CertificateError("hostname %r "
-                "doesn't match %r"
+            raise CertificateError(
+                "hostname %r doesn't match %r"
                 % (hostname, dnsnames[0]))
         else:
-            raise CertificateError("no appropriate commonName or "
+            raise CertificateError(
+                "no appropriate commonName or "
                 "subjectAltName fields were found")
 
 
@@ -158,7 +162,8 @@ class VerifyingHTTPSHandler(HTTPSHandler):
 
     def https_open(self, req):
         return self.do_open(
-            lambda host, **kw: VerifyingHTTPSConn(host, self.ca_bundle, **kw), req
+            lambda host, **kw: VerifyingHTTPSConn(host, self.ca_bundle, **kw),
+            req
         )
 
 
diff --git a/setuptools/tests/__init__.py b/setuptools/tests/__init__.py
index 5f4a1c29..6377d785 100644
--- a/setuptools/tests/__init__.py
+++ b/setuptools/tests/__init__.py
@@ -6,7 +6,7 @@ from setuptools.extern.six import PY2, PY3
 
 
 __all__ = [
-  'fail_on_ascii', 'py2_only', 'py3_only'
+    'fail_on_ascii', 'py2_only', 'py3_only', 'ack_2to3'
 ]
 
 
@@ -16,3 +16,5 @@ fail_on_ascii = pytest.mark.xfail(is_ascii, reason="Test fails in this locale")
 
 py2_only = pytest.mark.skipif(not PY2, reason="Test runs on Python 2 only")
 py3_only = pytest.mark.skipif(not PY3, reason="Test runs on Python 3 only")
+
+ack_2to3 = pytest.mark.filterwarnings('ignore:2to3 support is deprecated')
diff --git a/tests/requirements.txt b/setuptools/tests/requirements.txt
index cb3e6726..19bf5aef 100644
--- a/tests/requirements.txt
+++ b/setuptools/tests/requirements.txt
@@ -1,6 +1,6 @@
 mock
-pytest-flake8; python_version!="3.4"
-pytest-flake8<=1.0.0; python_version=="3.4"
+pytest-flake8
+flake8-2020; python_version>="3.6"
 virtualenv>=13.0.0
 pytest-virtualenv>=1.2.7
 pytest>=3.7
@@ -9,4 +9,4 @@ coverage>=4.5.1
 pytest-cov>=2.5.1
 paver; python_version>="3.6"
 futures; python_version=="2.7"
-pip==18.1  # Temporary workaround for #1644.
+pip>=19.1 # For proper file:// URLs support.
diff --git a/setuptools/tests/server.py b/setuptools/tests/server.py
index fc3a5975..8b17b081 100644
--- a/setuptools/tests/server.py
+++ b/setuptools/tests/server.py
@@ -1,10 +1,13 @@
 """Basic http server for tests to simulate PyPI or custom indexes
 """
 
+import os
 import time
 import threading
 
 from setuptools.extern.six.moves import BaseHTTPServer, SimpleHTTPServer
+from setuptools.extern.six.moves.urllib_parse import urljoin
+from setuptools.extern.six.moves.urllib.request import pathname2url
 
 
 class IndexServer(BaseHTTPServer.HTTPServer):
@@ -70,5 +73,19 @@ class MockServer(BaseHTTPServer.HTTPServer, threading.Thread):
         self.serve_forever()
 
     @property
+    def netloc(self):
+        return 'localhost:%s' % self.server_port
+
+    @property
     def url(self):
-        return 'http://localhost:%(server_port)s/' % vars(self)
+        return 'http://%s/' % self.netloc
+
+
+def path_to_url(path, authority=None):
+    """ Convert a path to a file: URL. """
+    path = os.path.normpath(os.path.abspath(path))
+    base = 'file:'
+    if authority is not None:
+        base += '//' + authority
+    url = urljoin(base, pathname2url(path))
+    return url
diff --git a/setuptools/tests/test_bdist_deprecations.py b/setuptools/tests/test_bdist_deprecations.py
new file mode 100644
index 00000000..704164aa
--- /dev/null
+++ b/setuptools/tests/test_bdist_deprecations.py
@@ -0,0 +1,23 @@
+"""develop tests
+"""
+import mock
+
+import pytest
+
+from setuptools.dist import Distribution
+from setuptools import SetuptoolsDeprecationWarning
+
+
+@mock.patch("distutils.command.bdist_wininst.bdist_wininst")
+def test_bdist_wininst_warning(distutils_cmd):
+    dist = Distribution(dict(
+        script_name='setup.py',
+        script_args=['bdist_wininst'],
+        name='foo',
+        py_modules=['hi'],
+    ))
+    dist.parse_command_line()
+    with pytest.warns(SetuptoolsDeprecationWarning):
+        dist.run_commands()
+
+    distutils_cmd.run.assert_called_once()
diff --git a/setuptools/tests/test_bdist_egg.py b/setuptools/tests/test_bdist_egg.py
index 54742aa6..8760ea30 100644
--- a/setuptools/tests/test_bdist_egg.py
+++ b/setuptools/tests/test_bdist_egg.py
@@ -7,6 +7,7 @@ import zipfile
 import pytest
 
 from setuptools.dist import Distribution
+from setuptools import SetuptoolsDeprecationWarning
 
 from . import contexts
 
@@ -42,7 +43,7 @@ class Test:
 
         # let's see if we got our egg link at the right place
         [content] = os.listdir('dist')
-        assert re.match(r'foo-0.0.0-py[23].\d.egg$', content)
+        assert re.match(r'foo-0.0.0-py[23].\d+.egg$', content)
 
     @pytest.mark.xfail(
         os.environ.get('PYTHONDONTWRITEBYTECODE'),
@@ -64,3 +65,17 @@ class Test:
         names = list(zi.filename for zi in zip.filelist)
         assert 'hi.pyc' in names
         assert 'hi.py' not in names
+
+    def test_eggsecutable_warning(self, setup_context, user_override):
+        dist = Distribution(dict(
+            script_name='setup.py',
+            script_args=['bdist_egg'],
+            name='foo',
+            py_modules=['hi'],
+            entry_points={
+                'setuptools.installation':
+                    ['eggsecutable = my_package.some_module:main_func']},
+        ))
+        dist.parse_command_line()
+        with pytest.warns(SetuptoolsDeprecationWarning):
+            dist.run_commands()
diff --git a/setuptools/tests/test_build_clib.py b/setuptools/tests/test_build_clib.py
index 3779e679..48bea2b4 100644
--- a/setuptools/tests/test_build_clib.py
+++ b/setuptools/tests/test_build_clib.py
@@ -8,8 +8,7 @@ from setuptools.dist import Distribution
 
 class TestBuildCLib:
     @mock.patch(
-            'setuptools.command.build_clib.newer_pairwise_group'
-            )
+        'setuptools.command.build_clib.newer_pairwise_group')
     def test_build_libraries(self, mock_newer):
         dist = Distribution()
         cmd = build_clib(dist)
diff --git a/setuptools/tests/test_build_meta.py b/setuptools/tests/test_build_meta.py
index e1efe561..8fcf3055 100644
--- a/setuptools/tests/test_build_meta.py
+++ b/setuptools/tests/test_build_meta.py
@@ -23,6 +23,7 @@ class BuildBackendBase:
         self.env = env
         self.backend_name = backend_name
 
+
 class BuildBackend(BuildBackendBase):
     """PEP 517 Build Backend"""
 
@@ -262,6 +263,27 @@ class TestBuildMetaBackend:
         assert os.path.isfile(
             os.path.join(os.path.abspath("out_sdist"), sdist_name))
 
+    def test_build_sdist_pyproject_toml_exists(self, tmpdir_cwd):
+        files = {
+            'setup.py': DALS("""
+                __import__('setuptools').setup(
+                    name='foo',
+                    version='0.0.0',
+                    py_modules=['hello']
+                )"""),
+            'hello.py': '',
+            'pyproject.toml': DALS("""
+                [build-system]
+                requires = ["setuptools", "wheel"]
+                build-backend = "setuptools.build_meta
+                """),
+        }
+        build_files(files)
+        build_backend = self.get_build_backend()
+        targz_path = build_backend.build_sdist("temp")
+        with tarfile.open(os.path.join("temp", targz_path)) as tar:
+            assert any('pyproject.toml' in name for name in tar.getnames())
+
     def test_build_sdist_setup_py_exists(self, tmpdir_cwd):
         # If build_sdist is called from a script other than setup.py,
         # ensure setup.py is included
@@ -385,6 +407,28 @@ class TestBuildMetaBackend:
 
         assert expected == sorted(actual)
 
+    _sys_argv_0_passthrough = {
+        'setup.py': DALS("""
+            import os
+            import sys
+
+            __import__('setuptools').setup(
+                name='foo',
+                version='0.0.0',
+            )
+
+            sys_argv = os.path.abspath(sys.argv[0])
+            file_path = os.path.abspath('setup.py')
+            assert sys_argv == file_path
+            """)
+    }
+
+    def test_sys_argv_passthrough(self, tmpdir_cwd):
+        build_files(self._sys_argv_0_passthrough)
+        build_backend = self.get_build_backend()
+        with pytest.raises(AssertionError):
+            build_backend.build_sdist("temp")
+
 
 class TestBuildMetaLegacyBackend(TestBuildMetaBackend):
     backend_name = 'setuptools.build_meta:__legacy__'
@@ -396,3 +440,9 @@ class TestBuildMetaLegacyBackend(TestBuildMetaBackend):
 
         build_backend = self.get_build_backend()
         build_backend.build_sdist("temp")
+
+    def test_sys_argv_passthrough(self, tmpdir_cwd):
+        build_files(self._sys_argv_0_passthrough)
+
+        build_backend = self.get_build_backend()
+        build_backend.build_sdist("temp")
diff --git a/setuptools/tests/test_build_py.py b/setuptools/tests/test_build_py.py
index b3a99f56..78a31ac4 100644
--- a/setuptools/tests/test_build_py.py
+++ b/setuptools/tests/test_build_py.py
@@ -1,4 +1,8 @@
 import os
+import stat
+import shutil
+
+import pytest
 
 from setuptools.dist import Distribution
 
@@ -20,3 +24,61 @@ def test_directories_in_package_data_glob(tmpdir_cwd):
     os.makedirs('path/subpath')
     dist.parse_command_line()
     dist.run_commands()
+
+
+def test_read_only(tmpdir_cwd):
+    """
+    Ensure read-only flag is not preserved in copy
+    for package modules and package data, as that
+    causes problems with deleting read-only files on
+    Windows.
+
+    #1451
+    """
+    dist = Distribution(dict(
+        script_name='setup.py',
+        script_args=['build_py'],
+        packages=['pkg'],
+        package_data={'pkg': ['data.dat']},
+        name='pkg',
+    ))
+    os.makedirs('pkg')
+    open('pkg/__init__.py', 'w').close()
+    open('pkg/data.dat', 'w').close()
+    os.chmod('pkg/__init__.py', stat.S_IREAD)
+    os.chmod('pkg/data.dat', stat.S_IREAD)
+    dist.parse_command_line()
+    dist.run_commands()
+    shutil.rmtree('build')
+
+
+@pytest.mark.xfail(
+    'platform.system() == "Windows"',
+    reason="On Windows, files do not have executable bits",
+    raises=AssertionError,
+    strict=True,
+)
+def test_executable_data(tmpdir_cwd):
+    """
+    Ensure executable bit is preserved in copy for
+    package data, as users rely on it for scripts.
+
+    #2041
+    """
+    dist = Distribution(dict(
+        script_name='setup.py',
+        script_args=['build_py'],
+        packages=['pkg'],
+        package_data={'pkg': ['run-me']},
+        name='pkg',
+    ))
+    os.makedirs('pkg')
+    open('pkg/__init__.py', 'w').close()
+    open('pkg/run-me', 'w').close()
+    os.chmod('pkg/run-me', 0o700)
+
+    dist.parse_command_line()
+    dist.run_commands()
+
+    assert os.stat('build/lib/pkg/run-me').st_mode & stat.S_IEXEC, \
+        "Script is not executable"
diff --git a/setuptools/tests/test_config.py b/setuptools/tests/test_config.py
index bc97664d..67992c04 100644
--- a/setuptools/tests/test_config.py
+++ b/setuptools/tests/test_config.py
@@ -1,7 +1,8 @@
-# -*- coding: UTF-8 -*-
+# -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 
 import contextlib
+
 import pytest
 
 from distutils.errors import DistutilsOptionError, DistutilsFileError
@@ -9,6 +10,7 @@ from mock import patch
 from setuptools.dist import Distribution, _Distribution
 from setuptools.config import ConfigHandler, read_configuration
 from setuptools.extern.six.moves import configparser
+from setuptools.extern import six
 from . import py2_only, py3_only
 from .textwrap import DALS
 
@@ -53,6 +55,7 @@ def fake_env(
         '    return [3, 4, 5, "dev"]\n'
         '\n'
     )
+
     return package_dir, config
 
 
@@ -267,11 +270,23 @@ class TestMetadata:
 
     def test_version(self, tmpdir):
 
-        _, config = fake_env(
+        package_dir, config = fake_env(
             tmpdir,
             '[metadata]\n'
             'version = attr: fake_package.VERSION\n'
         )
+
+        sub_a = package_dir.mkdir('subpkg_a')
+        sub_a.join('__init__.py').write('')
+        sub_a.join('mod.py').write('VERSION = (2016, 11, 26)')
+
+        sub_b = package_dir.mkdir('subpkg_b')
+        sub_b.join('__init__.py').write('')
+        sub_b.join('mod.py').write(
+            'import third_party_module\n'
+            'VERSION = (2016, 11, 26)'
+        )
+
         with get_dist(tmpdir) as dist:
             assert dist.metadata.version == '1.2.3'
 
@@ -289,13 +304,20 @@ class TestMetadata:
         with get_dist(tmpdir) as dist:
             assert dist.metadata.version == '1'
 
-        subpack = tmpdir.join('fake_package').mkdir('subpackage')
-        subpack.join('__init__.py').write('')
-        subpack.join('submodule.py').write('VERSION = (2016, 11, 26)')
+        config.write(
+            '[metadata]\n'
+            'version = attr: fake_package.subpkg_a.mod.VERSION\n'
+        )
+        with get_dist(tmpdir) as dist:
+            assert dist.metadata.version == '2016.11.26'
+
+        if six.PY2:
+            # static version loading is unsupported on Python 2
+            return
 
         config.write(
             '[metadata]\n'
-            'version = attr: fake_package.subpackage.submodule.VERSION\n'
+            'version = attr: fake_package.subpkg_b.mod.VERSION\n'
         )
         with get_dist(tmpdir) as dist:
             assert dist.metadata.version == '2016.11.26'
@@ -695,7 +717,7 @@ class TestOptions:
         )
         with get_dist(tmpdir) as dist:
             assert set(dist.packages) == set(
-                ['fake_package',  'fake_package.sub_two'])
+                ['fake_package', 'fake_package.sub_two'])
 
     @py2_only
     def test_find_namespace_directive_fails_on_py2(self, tmpdir):
@@ -748,7 +770,7 @@ class TestOptions:
         )
         with get_dist(tmpdir) as dist:
             assert set(dist.packages) == {
-                'fake_package',  'fake_package.sub_two'
+                'fake_package', 'fake_package.sub_two'
             }
 
     def test_extras_require(self, tmpdir):
@@ -819,6 +841,40 @@ class TestOptions:
             ]
             assert sorted(dist.data_files) == sorted(expected)
 
+    def test_python_requires_simple(self, tmpdir):
+        fake_env(
+            tmpdir,
+            DALS("""
+            [options]
+            python_requires=>=2.7
+            """),
+        )
+        with get_dist(tmpdir) as dist:
+            dist.parse_config_files()
+
+    def test_python_requires_compound(self, tmpdir):
+        fake_env(
+            tmpdir,
+            DALS("""
+            [options]
+            python_requires=>=2.7,!=3.0.*
+            """),
+        )
+        with get_dist(tmpdir) as dist:
+            dist.parse_config_files()
+
+    def test_python_requires_invalid(self, tmpdir):
+        fake_env(
+            tmpdir,
+            DALS("""
+            [options]
+            python_requires=invalid
+            """),
+        )
+        with pytest.raises(Exception):
+            with get_dist(tmpdir) as dist:
+                dist.parse_config_files()
+
 
 saved_dist_init = _Distribution.__init__
 
@@ -847,7 +903,7 @@ class TestExternalSetters:
         return None
 
     @patch.object(_Distribution, '__init__', autospec=True)
-    def test_external_setters(self,  mock_parent_init, tmpdir):
+    def test_external_setters(self, mock_parent_init, tmpdir):
         mock_parent_init.side_effect = self._fake_distribution_init
 
         dist = Distribution(attrs={
diff --git a/setuptools/tests/test_develop.py b/setuptools/tests/test_develop.py
index 00d4bd9a..bb89a865 100644
--- a/setuptools/tests/test_develop.py
+++ b/setuptools/tests/test_develop.py
@@ -17,6 +17,7 @@ import pytest
 
 from setuptools.command.develop import develop
 from setuptools.dist import Distribution
+from setuptools.tests import ack_2to3
 from . import contexts
 from . import namespaces
 
@@ -65,6 +66,7 @@ class TestDevelop:
     @pytest.mark.skipif(
         in_virtualenv or in_venv,
         reason="Cannot run when invoked in a virtualenv or venv")
+    @ack_2to3
     def test_2to3_user_mode(self, test_env):
         settings = dict(
             name='foo',
@@ -95,7 +97,7 @@ class TestDevelop:
         with io.open(fn) as init_file:
             init = init_file.read().strip()
 
-        expected = 'print("foo")' if six.PY3 else 'print "foo"'
+        expected = 'print "foo"' if six.PY2 else 'print("foo")'
         assert init == expected
 
     def test_console_scripts(self, tmpdir):
@@ -161,7 +163,7 @@ class TestNamespaces:
         reason="https://github.com/pypa/setuptools/issues/851",
     )
     @pytest.mark.skipif(
-        platform.python_implementation() == 'PyPy' and six.PY3,
+        platform.python_implementation() == 'PyPy' and not six.PY2,
         reason="https://github.com/pypa/setuptools/issues/1202",
     )
     def test_namespace_package_importable(self, tmpdir):
diff --git a/setuptools/tests/test_dist.py b/setuptools/tests/test_dist.py
index 390c3dfc..531ea1b4 100644
--- a/setuptools/tests/test_dist.py
+++ b/setuptools/tests/test_dist.py
@@ -3,7 +3,16 @@
 from __future__ import unicode_literals
 
 import io
-from setuptools.dist import DistDeprecationWarning, _get_unpatched
+import collections
+import re
+import functools
+from distutils.errors import DistutilsSetupError
+from setuptools.dist import (
+    _get_unpatched,
+    check_package_data,
+    DistDeprecationWarning,
+)
+from setuptools import sic
 from setuptools import Distribution
 from setuptools.extern.six.moves.urllib.request import pathname2url
 from setuptools.extern.six.moves.urllib_parse import urljoin
@@ -54,7 +63,8 @@ def test_dist_fetch_build_egg(tmpdir):
             dist.fetch_build_egg(r)
             for r in reqs
         ]
-    assert [dist.key for dist in resolved_dists if dist] == reqs
+    # noqa below because on Python 2 it causes flakes
+    assert [dist.key for dist in resolved_dists if dist] == reqs  # noqa
 
 
 def test_dist__get_unpatched_deprecated():
@@ -62,75 +72,72 @@ def test_dist__get_unpatched_deprecated():
 
 
 def __read_test_cases():
-    # Metadata version 1.0
-    base_attrs = {
-        "name": "package",
-        "version": "0.0.1",
-        "author": "Foo Bar",
-        "author_email": "foo@bar.net",
-        "long_description": "Long\ndescription",
-        "description": "Short description",
-        "keywords": ["one", "two"]
-    }
-
-    def merge_dicts(d1, d2):
-        d1 = d1.copy()
-        d1.update(d2)
-
-        return d1
+    base = dict(
+        name="package",
+        version="0.0.1",
+        author="Foo Bar",
+        author_email="foo@bar.net",
+        long_description="Long\ndescription",
+        description="Short description",
+        keywords=["one", "two"],
+    )
+
+    params = functools.partial(dict, base)
 
     test_cases = [
-        ('Metadata version 1.0', base_attrs.copy()),
-        ('Metadata version 1.1: Provides', merge_dicts(base_attrs, {
-            'provides': ['package']
-        })),
-        ('Metadata version 1.1: Obsoletes', merge_dicts(base_attrs, {
-            'obsoletes': ['foo']
-        })),
-        ('Metadata version 1.1: Classifiers', merge_dicts(base_attrs, {
-            'classifiers': [
+        ('Metadata version 1.0', params()),
+        ('Metadata version 1.1: Provides', params(
+            provides=['package'],
+        )),
+        ('Metadata version 1.1: Obsoletes', params(
+            obsoletes=['foo'],
+        )),
+        ('Metadata version 1.1: Classifiers', params(
+            classifiers=[
                 'Programming Language :: Python :: 3',
                 'Programming Language :: Python :: 3.7',
                 'License :: OSI Approved :: MIT License',
-            ]})),
-        ('Metadata version 1.1: Download URL', merge_dicts(base_attrs, {
-            'download_url': 'https://example.com'
-        })),
-        ('Metadata Version 1.2: Requires-Python', merge_dicts(base_attrs, {
-            'python_requires': '>=3.7'
-        })),
+            ],
+        )),
+        ('Metadata version 1.1: Download URL', params(
+            download_url='https://example.com',
+        )),
+        ('Metadata Version 1.2: Requires-Python', params(
+            python_requires='>=3.7',
+        )),
         pytest.param(
             'Metadata Version 1.2: Project-Url',
-            merge_dicts(base_attrs, {
-                'project_urls': {
-                    'Foo': 'https://example.bar'
-                }
-            }), marks=pytest.mark.xfail(
-                reason="Issue #1578: project_urls not read"
-            )),
-        ('Metadata Version 2.1: Long Description Content Type',
-         merge_dicts(base_attrs, {
-             'long_description_content_type': 'text/x-rst; charset=UTF-8'
-         })),
+            params(project_urls=dict(Foo='https://example.bar')),
+            marks=pytest.mark.xfail(
+                reason="Issue #1578: project_urls not read",
+            ),
+        ),
+        ('Metadata Version 2.1: Long Description Content Type', params(
+            long_description_content_type='text/x-rst; charset=UTF-8',
+        )),
         pytest.param(
             'Metadata Version 2.1: Provides Extra',
-            merge_dicts(base_attrs, {
-                'provides_extras': ['foo', 'bar']
-            }), marks=pytest.mark.xfail(reason="provides_extras not read")),
-        ('Missing author, missing author e-mail',
-         {'name': 'foo', 'version': '1.0.0'}),
-        ('Missing author',
-         {'name': 'foo',
-          'version': '1.0.0',
-          'author_email': 'snorri@sturluson.name'}),
-        ('Missing author e-mail',
-         {'name': 'foo',
-          'version': '1.0.0',
-          'author': 'Snorri Sturluson'}),
-        ('Missing author',
-         {'name': 'foo',
-          'version': '1.0.0',
-          'author': 'Snorri Sturluson'}),
+            params(provides_extras=['foo', 'bar']),
+            marks=pytest.mark.xfail(reason="provides_extras not read"),
+        ),
+        ('Missing author', dict(
+            name='foo',
+            version='1.0.0',
+            author_email='snorri@sturluson.name',
+        )),
+        ('Missing author e-mail', dict(
+            name='foo',
+            version='1.0.0',
+            author='Snorri Sturluson',
+        )),
+        ('Missing author and e-mail', dict(
+            name='foo',
+            version='1.0.0',
+        )),
+        ('Bypass normalized version', dict(
+            name='foo',
+            version=sic('1.0.0a'),
+        )),
     ]
 
     return test_cases
@@ -263,3 +270,64 @@ def test_maintainer_author(name, attrs, tmpdir):
         else:
             line = '%s: %s' % (fkey, val)
             assert line in pkg_lines_set
+
+
+def test_provides_extras_deterministic_order():
+    extras = collections.OrderedDict()
+    extras['a'] = ['foo']
+    extras['b'] = ['bar']
+    attrs = dict(extras_require=extras)
+    dist = Distribution(attrs)
+    assert dist.metadata.provides_extras == ['a', 'b']
+    attrs['extras_require'] = collections.OrderedDict(
+        reversed(list(attrs['extras_require'].items())))
+    dist = Distribution(attrs)
+    assert dist.metadata.provides_extras == ['b', 'a']
+
+
+CHECK_PACKAGE_DATA_TESTS = (
+    # Valid.
+    ({
+        '': ['*.txt', '*.rst'],
+        'hello': ['*.msg'],
+    }, None),
+    # Not a dictionary.
+    ((
+        ('', ['*.txt', '*.rst']),
+        ('hello', ['*.msg']),
+    ), (
+        "'package_data' must be a dictionary mapping package"
+        " names to lists of string wildcard patterns"
+    )),
+    # Invalid key type.
+    ({
+        400: ['*.txt', '*.rst'],
+    }, (
+        "keys of 'package_data' dict must be strings (got 400)"
+    )),
+    # Invalid value type.
+    ({
+        'hello': str('*.msg'),
+    }, (
+        "\"values of 'package_data' dict\" "
+        "must be a list of strings (got '*.msg')"
+    )),
+    # Invalid value type (generators are single use)
+    ({
+        'hello': (x for x in "generator"),
+    }, (
+        "\"values of 'package_data' dict\" must be a list of strings "
+        "(got <generator object"
+    )),
+)
+
+
+@pytest.mark.parametrize(
+    'package_data, expected_message', CHECK_PACKAGE_DATA_TESTS)
+def test_check_package_data(package_data, expected_message):
+    if expected_message is None:
+        assert check_package_data(None, 'package_data', package_data) is None
+    else:
+        with pytest.raises(
+                DistutilsSetupError, match=re.escape(expected_message)):
+            check_package_data(None, str('package_data'), package_data)
diff --git a/setuptools/tests/test_easy_install.py b/setuptools/tests/test_easy_install.py
index c3fd1c6e..3044cbd0 100644
--- a/setuptools/tests/test_easy_install.py
+++ b/setuptools/tests/test_easy_install.py
@@ -15,28 +15,29 @@ import distutils.errors
 import io
 import zipfile
 import mock
-from setuptools.command.easy_install import (
-    EasyInstallDeprecationWarning, ScriptWriter, WindowsScriptWriter,
-)
 import time
+
 from setuptools.extern import six
-from setuptools.extern.six.moves import urllib
 
 import pytest
 
 from setuptools import sandbox
 from setuptools.sandbox import run_setup
 import setuptools.command.easy_install as ei
-from setuptools.command.easy_install import PthDistributions
+from setuptools.command.easy_install import (
+    EasyInstallDeprecationWarning, ScriptWriter, PthDistributions,
+    WindowsScriptWriter,
+)
 from setuptools.command import easy_install as easy_install_pkg
 from setuptools.dist import Distribution
 from pkg_resources import normalize_path, working_set
 from pkg_resources import Distribution as PRDistribution
-import setuptools.tests.server
+from setuptools.tests.server import MockServer, path_to_url
 from setuptools.tests import fail_on_ascii
 import pkg_resources
 
 from . import contexts
+from .files import build_files
 from .textwrap import DALS
 
 __metaclass__ = type
@@ -440,35 +441,40 @@ def distutils_package():
         yield
 
 
+@pytest.fixture
+def mock_index():
+    # set up a server which will simulate an alternate package index.
+    p_index = MockServer()
+    if p_index.server_port == 0:
+        # Some platforms (Jython) don't find a port to which to bind,
+        # so skip test for them.
+        pytest.skip("could not find a valid port")
+    p_index.start()
+    return p_index
+
+
 class TestDistutilsPackage:
     def test_bdist_egg_available_on_distutils_pkg(self, distutils_package):
         run_setup('setup.py', ['bdist_egg'])
 
 
 class TestSetupRequires:
-    def test_setup_requires_honors_fetch_params(self):
+
+    def test_setup_requires_honors_fetch_params(self, mock_index, monkeypatch):
         """
         When easy_install installs a source distribution which specifies
         setup_requires, it should honor the fetch parameters (such as
-        allow-hosts, index-url, and find-links).
+        index-url, and find-links).
         """
-        # set up a server which will simulate an alternate package index.
-        p_index = setuptools.tests.server.MockServer()
-        p_index.start()
-        netloc = 1
-        p_index_loc = urllib.parse.urlparse(p_index.url)[netloc]
-        if p_index_loc.endswith(':0'):
-            # Some platforms (Jython) don't find a port to which to bind,
-            #  so skip this test for them.
-            return
+        monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+        monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
         with contexts.quiet():
             # create an sdist that has a build-time dependency.
             with TestSetupRequires.create_sdist() as dist_file:
                 with contexts.tempdir() as temp_install_dir:
                     with contexts.environment(PYTHONPATH=temp_install_dir):
                         ei_params = [
-                            '--index-url', p_index.url,
-                            '--allow-hosts', p_index_loc,
+                            '--index-url', mock_index.url,
                             '--exclude-scripts',
                             '--install-dir', temp_install_dir,
                             dist_file,
@@ -478,10 +484,8 @@ class TestSetupRequires:
                             # fail because it doesn't exist.
                             with pytest.raises(SystemExit):
                                 easy_install_pkg.main(ei_params)
-        # there should have been two or three requests to the server
-        #  (three happens on Python 3.3a)
-        assert 2 <= len(p_index.requests) <= 3
-        assert p_index.requests[0].path == '/does-not-exist/'
+        # there should have been one requests to the server
+        assert [r.path for r in mock_index.requests] == ['/does-not-exist/']
 
     @staticmethod
     @contextlib.contextmanager
@@ -500,7 +504,9 @@ class TestSetupRequires:
                         version="1.0",
                         setup_requires = ['does-not-exist'],
                     )
-                """))])
+                """)),
+                ('setup.cfg', ''),
+            ])
             yield dist_path
 
     use_setup_cfg = (
@@ -623,7 +629,7 @@ class TestSetupRequires:
                 test_pkg = create_setup_requires_package(
                     temp_dir, setup_attrs=dict(version='attr: foobar.version'),
                     make_package=make_dependency_sdist,
-                    use_setup_cfg=use_setup_cfg+('version',),
+                    use_setup_cfg=use_setup_cfg + ('version',),
                 )
                 test_setup_py = os.path.join(test_pkg, 'setup.py')
                 with contexts.quiet() as (stdout, stderr):
@@ -632,6 +638,208 @@ class TestSetupRequires:
                 assert len(lines) > 0
                 assert lines[-1].strip() == '42'
 
+    def test_setup_requires_honors_pip_env(self, mock_index, monkeypatch):
+        monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+        monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
+        monkeypatch.setenv(str('PIP_INDEX_URL'), mock_index.url)
+        with contexts.save_pkg_resources_state():
+            with contexts.tempdir() as temp_dir:
+                test_pkg = create_setup_requires_package(
+                    temp_dir, 'python-xlib', '0.19',
+                    setup_attrs=dict(dependency_links=[]))
+                test_setup_cfg = os.path.join(test_pkg, 'setup.cfg')
+                with open(test_setup_cfg, 'w') as fp:
+                    fp.write(DALS(
+                        '''
+                        [easy_install]
+                        index_url = https://pypi.org/legacy/
+                        '''))
+                test_setup_py = os.path.join(test_pkg, 'setup.py')
+                with pytest.raises(distutils.errors.DistutilsError):
+                    run_setup(test_setup_py, [str('--version')])
+        assert len(mock_index.requests) == 1
+        assert mock_index.requests[0].path == '/python-xlib/'
+
+    def test_setup_requires_with_pep508_url(self, mock_index, monkeypatch):
+        monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+        monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
+        monkeypatch.setenv(str('PIP_INDEX_URL'), mock_index.url)
+        with contexts.save_pkg_resources_state():
+            with contexts.tempdir() as temp_dir:
+                dep_sdist = os.path.join(temp_dir, 'dep.tar.gz')
+                make_trivial_sdist(dep_sdist, 'dependency', '42')
+                dep_url = path_to_url(dep_sdist, authority='localhost')
+                test_pkg = create_setup_requires_package(
+                    temp_dir,
+                    # Ignored (overriden by setup_attrs)
+                    'python-xlib', '0.19',
+                    setup_attrs=dict(
+                        setup_requires='dependency @ %s' % dep_url))
+                test_setup_py = os.path.join(test_pkg, 'setup.py')
+                run_setup(test_setup_py, [str('--version')])
+        assert len(mock_index.requests) == 0
+
+    def test_setup_requires_with_allow_hosts(self, mock_index):
+        ''' The `allow-hosts` option in not supported anymore. '''
+        with contexts.save_pkg_resources_state():
+            with contexts.tempdir() as temp_dir:
+                test_pkg = os.path.join(temp_dir, 'test_pkg')
+                test_setup_py = os.path.join(test_pkg, 'setup.py')
+                test_setup_cfg = os.path.join(test_pkg, 'setup.cfg')
+                os.mkdir(test_pkg)
+                with open(test_setup_py, 'w') as fp:
+                    fp.write(DALS(
+                        '''
+                        from setuptools import setup
+                        setup(setup_requires='python-xlib')
+                        '''))
+                with open(test_setup_cfg, 'w') as fp:
+                    fp.write(DALS(
+                        '''
+                        [easy_install]
+                        allow_hosts = *
+                        '''))
+                with pytest.raises(distutils.errors.DistutilsError):
+                    run_setup(test_setup_py, [str('--version')])
+        assert len(mock_index.requests) == 0
+
+    def test_setup_requires_with_python_requires(self, monkeypatch, tmpdir):
+        ''' Check `python_requires` is honored. '''
+        monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+        monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
+        monkeypatch.setenv(str('PIP_NO_INDEX'), str('1'))
+        monkeypatch.setenv(str('PIP_VERBOSE'), str('1'))
+        dep_1_0_sdist = 'dep-1.0.tar.gz'
+        dep_1_0_url = path_to_url(str(tmpdir / dep_1_0_sdist))
+        dep_1_0_python_requires = '>=2.7'
+        make_python_requires_sdist(
+            str(tmpdir / dep_1_0_sdist), 'dep', '1.0', dep_1_0_python_requires)
+        dep_2_0_sdist = 'dep-2.0.tar.gz'
+        dep_2_0_url = path_to_url(str(tmpdir / dep_2_0_sdist))
+        dep_2_0_python_requires = '!=' + '.'.join(
+            map(str, sys.version_info[:2])) + '.*'
+        make_python_requires_sdist(
+            str(tmpdir / dep_2_0_sdist), 'dep', '2.0', dep_2_0_python_requires)
+        index = tmpdir / 'index.html'
+        index.write_text(DALS(
+            '''
+            <!DOCTYPE html>
+            <html><head><title>Links for dep</title></head>
+            <body>
+                <h1>Links for dep</h1>
+                <a href="{dep_1_0_url}" data-requires-python="{dep_1_0_python_requires}">{dep_1_0_sdist}</a><br/>
+                <a href="{dep_2_0_url}" data-requires-python="{dep_2_0_python_requires}">{dep_2_0_sdist}</a><br/>
+            </body>
+            </html>
+            ''').format(  # noqa
+                dep_1_0_url=dep_1_0_url,
+                dep_1_0_sdist=dep_1_0_sdist,
+                dep_1_0_python_requires=dep_1_0_python_requires,
+                dep_2_0_url=dep_2_0_url,
+                dep_2_0_sdist=dep_2_0_sdist,
+                dep_2_0_python_requires=dep_2_0_python_requires,
+        ), 'utf-8')
+        index_url = path_to_url(str(index))
+        with contexts.save_pkg_resources_state():
+            test_pkg = create_setup_requires_package(
+                str(tmpdir),
+                'python-xlib', '0.19',  # Ignored (overriden by setup_attrs).
+                setup_attrs=dict(
+                    setup_requires='dep', dependency_links=[index_url]))
+            test_setup_py = os.path.join(test_pkg, 'setup.py')
+            run_setup(test_setup_py, [str('--version')])
+        eggs = list(map(str, pkg_resources.find_distributions(
+            os.path.join(test_pkg, '.eggs'))))
+        assert eggs == ['dep 1.0']
+
+    @pytest.mark.parametrize(
+        'use_legacy_installer,with_dependency_links_in_setup_py',
+        itertools.product((False, True), (False, True)))
+    def test_setup_requires_with_find_links_in_setup_cfg(
+            self, monkeypatch, use_legacy_installer,
+            with_dependency_links_in_setup_py):
+        monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+        monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
+        with contexts.save_pkg_resources_state():
+            with contexts.tempdir() as temp_dir:
+                make_trivial_sdist(
+                    os.path.join(temp_dir, 'python-xlib-42.tar.gz'),
+                    'python-xlib',
+                    '42')
+                test_pkg = os.path.join(temp_dir, 'test_pkg')
+                test_setup_py = os.path.join(test_pkg, 'setup.py')
+                test_setup_cfg = os.path.join(test_pkg, 'setup.cfg')
+                os.mkdir(test_pkg)
+                with open(test_setup_py, 'w') as fp:
+                    if with_dependency_links_in_setup_py:
+                        dependency_links = [os.path.join(temp_dir, 'links')]
+                    else:
+                        dependency_links = []
+                    fp.write(DALS(
+                        '''
+                        from setuptools import installer, setup
+                        if {use_legacy_installer}:
+                            installer.fetch_build_egg = installer._legacy_fetch_build_egg
+                        setup(setup_requires='python-xlib==42',
+                        dependency_links={dependency_links!r})
+                        ''').format(use_legacy_installer=use_legacy_installer,  # noqa
+                                    dependency_links=dependency_links))
+                with open(test_setup_cfg, 'w') as fp:
+                    fp.write(DALS(
+                        '''
+                        [easy_install]
+                        index_url = {index_url}
+                        find_links = {find_links}
+                        ''').format(index_url=os.path.join(temp_dir, 'index'),
+                                    find_links=temp_dir))
+                run_setup(test_setup_py, [str('--version')])
+
+    def test_setup_requires_with_transitive_extra_dependency(
+            self, monkeypatch):
+        # Use case: installing a package with a build dependency on
+        # an already installed `dep[extra]`, which in turn depends
+        # on `extra_dep` (whose is not already installed).
+        with contexts.save_pkg_resources_state():
+            with contexts.tempdir() as temp_dir:
+                # Create source distribution for `extra_dep`.
+                make_trivial_sdist(
+                    os.path.join(temp_dir, 'extra_dep-1.0.tar.gz'),
+                    'extra_dep', '1.0')
+                # Create source tree for `dep`.
+                dep_pkg = os.path.join(temp_dir, 'dep')
+                os.mkdir(dep_pkg)
+                build_files({
+                    'setup.py':
+                    DALS("""
+                          import setuptools
+                          setuptools.setup(
+                              name='dep', version='2.0',
+                              extras_require={'extra': ['extra_dep']},
+                          )
+                         """),
+                    'setup.cfg': '',
+                }, prefix=dep_pkg)
+                # "Install" dep.
+                run_setup(
+                    os.path.join(dep_pkg, 'setup.py'), [str('dist_info')])
+                working_set.add_entry(dep_pkg)
+                # Create source tree for test package.
+                test_pkg = os.path.join(temp_dir, 'test_pkg')
+                test_setup_py = os.path.join(test_pkg, 'setup.py')
+                os.mkdir(test_pkg)
+                with open(test_setup_py, 'w') as fp:
+                    fp.write(DALS(
+                        '''
+                        from setuptools import installer, setup
+                        setup(setup_requires='dep[extra]')
+                        '''))
+                # Check...
+                monkeypatch.setenv(str('PIP_FIND_LINKS'), str(temp_dir))
+                monkeypatch.setenv(str('PIP_NO_INDEX'), str('1'))
+                monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+                monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
+                run_setup(test_setup_py, [str('--version')])
+
 
 def make_trivial_sdist(dist_path, distname, version):
     """
@@ -647,7 +855,9 @@ def make_trivial_sdist(dist_path, distname, version):
                  name=%r,
                  version=%r
              )
-         """ % (distname, version)))])
+         """ % (distname, version))),
+        ('setup.cfg', ''),
+    ])
 
 
 def make_nspkg_sdist(dist_path, distname, version):
@@ -683,12 +893,32 @@ def make_nspkg_sdist(dist_path, distname, version):
     make_sdist(dist_path, files)
 
 
+def make_python_requires_sdist(dist_path, distname, version, python_requires):
+    make_sdist(dist_path, [
+        (
+            'setup.py',
+            DALS("""\
+                import setuptools
+                setuptools.setup(
+                  name={name!r},
+                  version={version!r},
+                  python_requires={python_requires!r},
+                )
+                """).format(
+                name=distname, version=version,
+                python_requires=python_requires)),
+        ('setup.cfg', ''),
+    ])
+
+
 def make_sdist(dist_path, files):
     """
     Create a simple sdist tarball at dist_path, containing the files
     listed in ``files`` as ``(filename, content)`` tuples.
     """
 
+    # Distributions with only one file don't play well with pip.
+    assert len(files) > 1
     with tarfile.open(dist_path, 'w:gz') as dist:
         for filename, content in files:
             file_bytes = io.BytesIO(content.encode('utf-8'))
@@ -721,8 +951,8 @@ def create_setup_requires_package(path, distname='foobar', version='0.1',
     test_pkg = os.path.join(path, 'test_pkg')
     os.mkdir(test_pkg)
 
+    # setup.cfg
     if use_setup_cfg:
-        test_setup_cfg = os.path.join(test_pkg, 'setup.cfg')
         options = []
         metadata = []
         for name in use_setup_cfg:
@@ -734,27 +964,29 @@ def create_setup_requires_package(path, distname='foobar', version='0.1',
             if isinstance(value, (tuple, list)):
                 value = ';'.join(value)
             section.append('%s: %s' % (name, value))
-        with open(test_setup_cfg, 'w') as f:
-            f.write(DALS(
-                """
-                [metadata]
-                {metadata}
-                [options]
-                {options}
-                """
-            ).format(
-                options='\n'.join(options),
-                metadata='\n'.join(metadata),
-            ))
-
-    test_setup_py = os.path.join(test_pkg, 'setup.py')
+        test_setup_cfg_contents = DALS(
+            """
+            [metadata]
+            {metadata}
+            [options]
+            {options}
+            """
+        ).format(
+            options='\n'.join(options),
+            metadata='\n'.join(metadata),
+        )
+    else:
+        test_setup_cfg_contents = ''
+    with open(os.path.join(test_pkg, 'setup.cfg'), 'w') as f:
+        f.write(test_setup_cfg_contents)
 
+    # setup.py
     if setup_py_template is None:
         setup_py_template = DALS("""\
             import setuptools
             setuptools.setup(**%r)
         """)
-    with open(test_setup_py, 'w') as f:
+    with open(os.path.join(test_pkg, 'setup.py'), 'w') as f:
         f.write(setup_py_template % test_setup_attrs)
 
     foobar_path = os.path.join(path, '%s-%s.tar.gz' % (distname, version))
diff --git a/setuptools/tests/test_egg_info.py b/setuptools/tests/test_egg_info.py
index 316eb2ed..109f9135 100644
--- a/setuptools/tests/test_egg_info.py
+++ b/setuptools/tests/test_egg_info.py
@@ -524,28 +524,28 @@ class TestEggInfo:
                               [metadata]
                               license_file = LICENSE
                               """),
-            'LICENSE': DALS("Test license")
-        }, True), # with license
+            'LICENSE': "Test license"
+        }, True),  # with license
         ({
             'setup.cfg': DALS("""
                               [metadata]
                               license_file = INVALID_LICENSE
                               """),
-            'LICENSE': DALS("Test license")
-        }, False), # with an invalid license
+            'LICENSE': "Test license"
+        }, False),  # with an invalid license
         ({
             'setup.cfg': DALS("""
                               """),
-            'LICENSE': DALS("Test license")
-        }, False), # no license_file attribute
+            'LICENSE': "Test license"
+        }, False),  # no license_file attribute
         ({
             'setup.cfg': DALS("""
                               [metadata]
                               license_file = LICENSE
                               """),
-            'MANIFEST.in': DALS("exclude LICENSE"),
-            'LICENSE': DALS("Test license")
-        }, False) # license file is manually excluded
+            'MANIFEST.in': "exclude LICENSE",
+            'LICENSE': "Test license"
+        }, False)  # license file is manually excluded
     ])
     def test_setup_cfg_license_file(
             self, tmpdir_cwd, env, files, license_in_sources):
@@ -565,7 +565,211 @@ class TestEggInfo:
             assert 'LICENSE' in sources_text
         else:
             assert 'LICENSE' not in sources_text
-            assert 'INVALID_LICENSE' not in sources_text # for invalid license test
+            # for invalid license test
+            assert 'INVALID_LICENSE' not in sources_text
+
+    @pytest.mark.parametrize("files, incl_licenses, excl_licenses", [
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files =
+                                  LICENSE-ABC
+                                  LICENSE-XYZ
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, ['LICENSE-ABC', 'LICENSE-XYZ'], []),  # with licenses
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files = LICENSE-ABC, LICENSE-XYZ
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, ['LICENSE-ABC', 'LICENSE-XYZ'], []),  # with commas
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files =
+                                  LICENSE-ABC
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, ['LICENSE-ABC'], ['LICENSE-XYZ']),  # with one license
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files =
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, [], ['LICENSE-ABC', 'LICENSE-XYZ']),  # empty
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files = LICENSE-XYZ
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, ['LICENSE-XYZ'], ['LICENSE-ABC']),  # on same line
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files =
+                                  LICENSE-ABC
+                                  INVALID_LICENSE
+                              """),
+            'LICENSE-ABC': "Test license"
+        }, ['LICENSE-ABC'], ['INVALID_LICENSE']),  # with an invalid license
+        ({
+            'setup.cfg': DALS("""
+                              """),
+            'LICENSE': "Test license"
+        }, [], ['LICENSE']),  # no license_files attribute
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files = LICENSE
+                              """),
+            'MANIFEST.in': "exclude LICENSE",
+            'LICENSE': "Test license"
+        }, [], ['LICENSE']),  # license file is manually excluded
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_files =
+                                  LICENSE-ABC
+                                  LICENSE-XYZ
+                              """),
+            'MANIFEST.in': "exclude LICENSE-XYZ",
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, ['LICENSE-ABC'], ['LICENSE-XYZ'])  # subset is manually excluded
+    ])
+    def test_setup_cfg_license_files(
+            self, tmpdir_cwd, env, files, incl_licenses, excl_licenses):
+        self._create_project()
+        build_files(files)
+
+        environment.run_setup_py(
+            cmd=['egg_info'],
+            pypath=os.pathsep.join([env.paths['lib'], str(tmpdir_cwd)])
+        )
+        egg_info_dir = os.path.join('.', 'foo.egg-info')
+
+        with open(os.path.join(egg_info_dir, 'SOURCES.txt')) as sources_file:
+            sources_lines = list(line.strip() for line in sources_file)
+
+        for lf in incl_licenses:
+            assert sources_lines.count(lf) == 1
+
+        for lf in excl_licenses:
+            assert sources_lines.count(lf) == 0
+
+    @pytest.mark.parametrize("files, incl_licenses, excl_licenses", [
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file =
+                              license_files =
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+        }, [], ['LICENSE-ABC', 'LICENSE-XYZ']),  # both empty
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file =
+                                  LICENSE-ABC
+                                  LICENSE-XYZ
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-XYZ': "XYZ license"
+            # license_file is still singular
+        }, [], ['LICENSE-ABC', 'LICENSE-XYZ']),
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file = LICENSE-ABC
+                              license_files =
+                                  LICENSE-XYZ
+                                  LICENSE-PQR
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-PQR': "PQR license",
+            'LICENSE-XYZ': "XYZ license"
+        }, ['LICENSE-ABC', 'LICENSE-PQR', 'LICENSE-XYZ'], []),  # combined
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file = LICENSE-ABC
+                              license_files =
+                                  LICENSE-ABC
+                                  LICENSE-XYZ
+                                  LICENSE-PQR
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-PQR': "PQR license",
+            'LICENSE-XYZ': "XYZ license"
+            # duplicate license
+        }, ['LICENSE-ABC', 'LICENSE-PQR', 'LICENSE-XYZ'], []),
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file = LICENSE-ABC
+                              license_files =
+                                  LICENSE-XYZ
+                              """),
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-PQR': "PQR license",
+            'LICENSE-XYZ': "XYZ license"
+            # combined subset
+        }, ['LICENSE-ABC', 'LICENSE-XYZ'], ['LICENSE-PQR']),
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file = LICENSE-ABC
+                              license_files =
+                                  LICENSE-XYZ
+                                  LICENSE-PQR
+                              """),
+            'LICENSE-PQR': "Test license"
+            # with invalid licenses
+        }, ['LICENSE-PQR'], ['LICENSE-ABC', 'LICENSE-XYZ']),
+        ({
+            'setup.cfg': DALS("""
+                              [metadata]
+                              license_file = LICENSE-ABC
+                              license_files =
+                                LICENSE-PQR
+                                LICENSE-XYZ
+                              """),
+            'MANIFEST.in': "exclude LICENSE-ABC\nexclude LICENSE-PQR",
+            'LICENSE-ABC': "ABC license",
+            'LICENSE-PQR': "PQR license",
+            'LICENSE-XYZ': "XYZ license"
+            # manually excluded
+        }, ['LICENSE-XYZ'], ['LICENSE-ABC', 'LICENSE-PQR'])
+    ])
+    def test_setup_cfg_license_file_license_files(
+            self, tmpdir_cwd, env, files, incl_licenses, excl_licenses):
+        self._create_project()
+        build_files(files)
+
+        environment.run_setup_py(
+            cmd=['egg_info'],
+            pypath=os.pathsep.join([env.paths['lib'], str(tmpdir_cwd)])
+        )
+        egg_info_dir = os.path.join('.', 'foo.egg-info')
+
+        with open(os.path.join(egg_info_dir, 'SOURCES.txt')) as sources_file:
+            sources_lines = list(line.strip() for line in sources_file)
+
+        for lf in incl_licenses:
+            assert sources_lines.count(lf) == 1
+
+        for lf in excl_licenses:
+            assert sources_lines.count(lf) == 0
 
     def test_long_description_content_type(self, tmpdir_cwd, env):
         # Test that specifying a `long_description_content_type` keyword arg to
diff --git a/setuptools/tests/test_extern.py b/setuptools/tests/test_extern.py
new file mode 100644
index 00000000..3519a680
--- /dev/null
+++ b/setuptools/tests/test_extern.py
@@ -0,0 +1,22 @@
+import importlib
+import pickle
+
+from setuptools import Distribution
+from setuptools.extern import ordered_set
+from setuptools.tests import py3_only
+
+
+def test_reimport_extern():
+    ordered_set2 = importlib.import_module(ordered_set.__name__)
+    assert ordered_set is ordered_set2
+
+
+def test_orderedset_pickle_roundtrip():
+    o1 = ordered_set.OrderedSet([1, 2, 5])
+    o2 = pickle.loads(pickle.dumps(o1))
+    assert o1 == o2
+
+
+@py3_only
+def test_distribution_picklable():
+    pickle.loads(pickle.dumps(Distribution()))
diff --git a/setuptools/tests/test_glibc.py b/setuptools/tests/test_glibc.py
deleted file mode 100644
index 795fdc56..00000000
--- a/setuptools/tests/test_glibc.py
+++ /dev/null
@@ -1,52 +0,0 @@
-import warnings
-
-import pytest
-
-from setuptools.glibc import check_glibc_version
-
-__metaclass__ = type
-
-
-@pytest.fixture(params=[
-    "2.20",
-    # used by "linaro glibc", see gh-3588
-    "2.20-2014.11",
-    # weird possibilities that I just made up
-    "2.20+dev",
-    "2.20-custom",
-    "2.20.1",
-    ])
-def two_twenty(request):
-    return request.param
-
-
-@pytest.fixture(params=["asdf", "", "foo.bar"])
-def bad_string(request):
-    return request.param
-
-
-class TestGlibc:
-    def test_manylinux1_check_glibc_version(self, two_twenty):
-        """
-        Test that the check_glibc_version function is robust against weird
-        glibc version strings.
-        """
-        assert check_glibc_version(two_twenty, 2, 15)
-        assert check_glibc_version(two_twenty, 2, 20)
-        assert not check_glibc_version(two_twenty, 2, 21)
-        assert not check_glibc_version(two_twenty, 3, 15)
-        assert not check_glibc_version(two_twenty, 1, 15)
-
-    def test_bad_versions(self, bad_string):
-        """
-        For unparseable strings, warn and return False
-        """
-        with warnings.catch_warnings(record=True) as ws:
-            warnings.filterwarnings("always")
-            assert not check_glibc_version(bad_string, 2, 5)
-            for w in ws:
-                if "Expected glibc version with" in str(w.message):
-                    break
-            else:
-                # Didn't find the warning we were expecting
-                assert False
diff --git a/setuptools/tests/test_integration.py b/setuptools/tests/test_integration.py
index 1e132188..f1a27f8b 100644
--- a/setuptools/tests/test_integration.py
+++ b/setuptools/tests/test_integration.py
@@ -64,7 +64,7 @@ def install_context(request, tmpdir, monkeypatch):
     monkeypatch.setattr('site.USER_BASE', user_base.strpath)
     monkeypatch.setattr('site.USER_SITE', user_site.strpath)
     monkeypatch.setattr('sys.path', sys.path + [install_dir.strpath])
-    monkeypatch.setenv('PYTHONPATH', os.path.pathsep.join(sys.path))
+    monkeypatch.setenv(str('PYTHONPATH'), str(os.path.pathsep.join(sys.path)))
 
     # Set up the command for performing the installation.
     dist = Distribution()
@@ -143,6 +143,7 @@ def test_build_deps_on_distutils(request, tmpdir_factory, build_dep):
             'tests_require',
             'python_requires',
             'install_requires',
+            'long_description_content_type',
         ]
         assert not match or match.group(1).strip('"\'') in allowed_unknowns
 
diff --git a/setuptools/tests/test_msvc14.py b/setuptools/tests/test_msvc14.py
new file mode 100644
index 00000000..7833aab4
--- /dev/null
+++ b/setuptools/tests/test_msvc14.py
@@ -0,0 +1,84 @@
+# -*- coding: utf-8 -*-
+"""
+Tests for msvc support module (msvc14 unit tests).
+"""
+
+import os
+from distutils.errors import DistutilsPlatformError
+import pytest
+import sys
+
+
+@pytest.mark.skipif(sys.platform != "win32",
+                    reason="These tests are only for win32")
+class TestMSVC14:
+    """Python 3.8 "distutils/tests/test_msvccompiler.py" backport"""
+    def test_no_compiler(self):
+        import setuptools.msvc as _msvccompiler
+        # makes sure query_vcvarsall raises
+        # a DistutilsPlatformError if the compiler
+        # is not found
+
+        def _find_vcvarsall(plat_spec):
+            return None, None
+
+        old_find_vcvarsall = _msvccompiler._msvc14_find_vcvarsall
+        _msvccompiler._msvc14_find_vcvarsall = _find_vcvarsall
+        try:
+            pytest.raises(DistutilsPlatformError,
+                          _msvccompiler._msvc14_get_vc_env,
+                          'wont find this version')
+        finally:
+            _msvccompiler._msvc14_find_vcvarsall = old_find_vcvarsall
+
+    @pytest.mark.skipif(sys.version_info[0] < 3,
+                        reason="Unicode requires encode/decode on Python 2")
+    def test_get_vc_env_unicode(self):
+        import setuptools.msvc as _msvccompiler
+
+        test_var = 'ṰḖṤṪ┅ṼẨṜ'
+        test_value = '₃⁴₅'
+
+        # Ensure we don't early exit from _get_vc_env
+        old_distutils_use_sdk = os.environ.pop('DISTUTILS_USE_SDK', None)
+        os.environ[test_var] = test_value
+        try:
+            env = _msvccompiler._msvc14_get_vc_env('x86')
+            assert test_var.lower() in env
+            assert test_value == env[test_var.lower()]
+        finally:
+            os.environ.pop(test_var)
+            if old_distutils_use_sdk:
+                os.environ['DISTUTILS_USE_SDK'] = old_distutils_use_sdk
+
+    def test_get_vc2017(self):
+        import setuptools.msvc as _msvccompiler
+
+        # This function cannot be mocked, so pass it if we find VS 2017
+        # and mark it skipped if we do not.
+        version, path = _msvccompiler._msvc14_find_vc2017()
+        if os.environ.get('APPVEYOR_BUILD_WORKER_IMAGE', '') in [
+            'Visual Studio 2017'
+        ]:
+            assert version
+        if version:
+            assert version >= 15
+            assert os.path.isdir(path)
+        else:
+            pytest.skip("VS 2017 is not installed")
+
+    def test_get_vc2015(self):
+        import setuptools.msvc as _msvccompiler
+
+        # This function cannot be mocked, so pass it if we find VS 2015
+        # and mark it skipped if we do not.
+        version, path = _msvccompiler._msvc14_find_vc2015()
+        if os.environ.get('APPVEYOR_BUILD_WORKER_IMAGE', '') in [
+            'Visual Studio 2015', 'Visual Studio 2017'
+        ]:
+            assert version
+        if version:
+            assert version >= 14
+            assert os.path.isdir(path)
+        else:
+            pytest.skip("VS 2015 is not installed")
diff --git a/setuptools/tests/test_packageindex.py b/setuptools/tests/test_packageindex.py
index 60d968fd..29aace13 100644
--- a/setuptools/tests/test_packageindex.py
+++ b/setuptools/tests/test_packageindex.py
@@ -3,15 +3,14 @@ from __future__ import absolute_import
 import sys
 import os
 import distutils.errors
+import platform
 
 from setuptools.extern import six
 from setuptools.extern.six.moves import urllib, http_client
 import mock
 import pytest
 
-import pkg_resources
 import setuptools.package_index
-from setuptools.tests.server import IndexServer
 from .textwrap import DALS
 
 
@@ -114,43 +113,6 @@ class TestPackageIndex:
         url = 'file:///tmp/test_package_index'
         assert index.url_ok(url, True)
 
-    def test_links_priority(self):
-        """
-        Download links from the pypi simple index should be used before
-        external download links.
-        https://bitbucket.org/tarek/distribute/issue/163
-
-        Usecase :
-        - someone uploads a package on pypi, a md5 is generated
-        - someone manually copies this link (with the md5 in the url) onto an
-          external page accessible from the package page.
-        - someone reuploads the package (with a different md5)
-        - while easy_installing, an MD5 error occurs because the external link
-          is used
-        -> Setuptools should use the link from pypi, not the external one.
-        """
-        if sys.platform.startswith('java'):
-            # Skip this test on jython because binding to :0 fails
-            return
-
-        # start an index server
-        server = IndexServer()
-        server.start()
-        index_url = server.base_url() + 'test_links_priority/simple/'
-
-        # scan a test index
-        pi = setuptools.package_index.PackageIndex(index_url)
-        requirement = pkg_resources.Requirement.parse('foobar')
-        pi.find_packages(requirement)
-        server.stop()
-
-        # the distribution has been found
-        assert 'foobar' in pi
-        # we have only one link, because links are compared without md5
-        assert len(pi['foobar']) == 1
-        # the link should be from the index
-        assert 'correct_md5' in pi['foobar'][0].location
-
     def test_parse_bdist_wininst(self):
         parse = setuptools.package_index.parse_bdist_wininst
 
@@ -221,11 +183,11 @@ class TestPackageIndex:
             ('+ubuntu_0', '+ubuntu.0'),
         ]
         versions = [
-            [''.join([e, r, p, l]) for l in ll]
+            [''.join([e, r, p, loc]) for loc in locs]
             for e in epoch
             for r in releases
             for p in sum([pre, post, dev], [''])
-            for ll in local]
+            for locs in local]
         for v, vc in versions:
             dists = list(setuptools.package_index.distros_for_url(
                 'http://example.com/example.zip#egg=example-' + v))
@@ -322,17 +284,27 @@ class TestContentCheckers:
         assert rep == 'My message about md5'
 
 
+@pytest.fixture
+def temp_home(tmpdir, monkeypatch):
+    key = (
+        'USERPROFILE'
+        if platform.system() == 'Windows' and sys.version_info > (3, 8) else
+        'HOME'
+    )
+
+    monkeypatch.setitem(os.environ, key, str(tmpdir))
+    return tmpdir
+
+
 class TestPyPIConfig:
-    def test_percent_in_password(self, tmpdir, monkeypatch):
-        monkeypatch.setitem(os.environ, 'HOME', str(tmpdir))
-        pypirc = tmpdir / '.pypirc'
-        with pypirc.open('w') as strm:
-            strm.write(DALS("""
-                [pypi]
-                repository=https://pypi.org
-                username=jaraco
-                password=pity%
-            """))
+    def test_percent_in_password(self, temp_home):
+        pypirc = temp_home / '.pypirc'
+        pypirc.write(DALS("""
+            [pypi]
+            repository=https://pypi.org
+            username=jaraco
+            password=pity%
+        """))
         cfg = setuptools.package_index.PyPIConfig()
         cred = cfg.creds_by_repository['https://pypi.org']
         assert cred.username == 'jaraco'
diff --git a/setuptools/tests/test_pep425tags.py b/setuptools/tests/test_pep425tags.py
deleted file mode 100644
index 30afdec7..00000000
--- a/setuptools/tests/test_pep425tags.py
+++ /dev/null
@@ -1,170 +0,0 @@
-import sys
-
-import pytest
-from mock import patch
-
-from setuptools import pep425tags
-
-__metaclass__ = type
-
-
-class TestPEP425Tags:
-
-    def mock_get_config_var(self, **kwd):
-        """
-        Patch sysconfig.get_config_var for arbitrary keys.
-        """
-        get_config_var = pep425tags.sysconfig.get_config_var
-
-        def _mock_get_config_var(var):
-            if var in kwd:
-                return kwd[var]
-            return get_config_var(var)
-        return _mock_get_config_var
-
-    def abi_tag_unicode(self, flags, config_vars):
-        """
-        Used to test ABI tags, verify correct use of the `u` flag
-        """
-        config_vars.update({'SOABI': None})
-        base = pep425tags.get_abbr_impl() + pep425tags.get_impl_ver()
-
-        if sys.version_info < (3, 3):
-            config_vars.update({'Py_UNICODE_SIZE': 2})
-            mock_gcf = self.mock_get_config_var(**config_vars)
-            with patch(
-                    'setuptools.pep425tags.sysconfig.get_config_var',
-                    mock_gcf):
-                abi_tag = pep425tags.get_abi_tag()
-                assert abi_tag == base + flags
-
-            config_vars.update({'Py_UNICODE_SIZE': 4})
-            mock_gcf = self.mock_get_config_var(**config_vars)
-            with patch('setuptools.pep425tags.sysconfig.get_config_var',
-                       mock_gcf):
-                abi_tag = pep425tags.get_abi_tag()
-                assert abi_tag == base + flags + 'u'
-
-        else:
-            # On Python >= 3.3, UCS-4 is essentially permanently enabled, and
-            # Py_UNICODE_SIZE is None. SOABI on these builds does not include
-            # the 'u' so manual SOABI detection should not do so either.
-            config_vars.update({'Py_UNICODE_SIZE': None})
-            mock_gcf = self.mock_get_config_var(**config_vars)
-            with patch('setuptools.pep425tags.sysconfig.get_config_var',
-                       mock_gcf):
-                abi_tag = pep425tags.get_abi_tag()
-                assert abi_tag == base + flags
-
-    def test_broken_sysconfig(self):
-        """
-        Test that pep425tags still works when sysconfig is broken.
-        Can be a problem on Python 2.7
-        Issue #1074.
-        """
-        def raises_ioerror(var):
-            raise IOError("I have the wrong path!")
-
-        with patch('setuptools.pep425tags.sysconfig.get_config_var',
-                   raises_ioerror):
-            with pytest.warns(RuntimeWarning):
-                assert len(pep425tags.get_supported())
-
-    def test_no_hyphen_tag(self):
-        """
-        Test that no tag contains a hyphen.
-        """
-        mock_gcf = self.mock_get_config_var(SOABI='cpython-35m-darwin')
-
-        with patch('setuptools.pep425tags.sysconfig.get_config_var',
-                   mock_gcf):
-            supported = pep425tags.get_supported()
-
-        for (py, abi, plat) in supported:
-            assert '-' not in py
-            assert '-' not in abi
-            assert '-' not in plat
-
-    def test_manual_abi_noflags(self):
-        """
-        Test that no flags are set on a non-PyDebug, non-Pymalloc ABI tag.
-        """
-        self.abi_tag_unicode('', {'Py_DEBUG': False, 'WITH_PYMALLOC': False})
-
-    def test_manual_abi_d_flag(self):
-        """
-        Test that the `d` flag is set on a PyDebug, non-Pymalloc ABI tag.
-        """
-        self.abi_tag_unicode('d', {'Py_DEBUG': True, 'WITH_PYMALLOC': False})
-
-    def test_manual_abi_m_flag(self):
-        """
-        Test that the `m` flag is set on a non-PyDebug, Pymalloc ABI tag.
-        """
-        self.abi_tag_unicode('m', {'Py_DEBUG': False, 'WITH_PYMALLOC': True})
-
-    def test_manual_abi_dm_flags(self):
-        """
-        Test that the `dm` flags are set on a PyDebug, Pymalloc ABI tag.
-        """
-        self.abi_tag_unicode('dm', {'Py_DEBUG': True, 'WITH_PYMALLOC': True})
-
-
-class TestManylinux1Tags:
-
-    @patch('setuptools.pep425tags.get_platform', lambda: 'linux_x86_64')
-    @patch('setuptools.glibc.have_compatible_glibc',
-           lambda major, minor: True)
-    def test_manylinux1_compatible_on_linux_x86_64(self):
-        """
-        Test that manylinux1 is enabled on linux_x86_64
-        """
-        assert pep425tags.is_manylinux1_compatible()
-
-    @patch('setuptools.pep425tags.get_platform', lambda: 'linux_i686')
-    @patch('setuptools.glibc.have_compatible_glibc',
-           lambda major, minor: True)
-    def test_manylinux1_compatible_on_linux_i686(self):
-        """
-        Test that manylinux1 is enabled on linux_i686
-        """
-        assert pep425tags.is_manylinux1_compatible()
-
-    @patch('setuptools.pep425tags.get_platform', lambda: 'linux_x86_64')
-    @patch('setuptools.glibc.have_compatible_glibc',
-           lambda major, minor: False)
-    def test_manylinux1_2(self):
-        """
-        Test that manylinux1 is disabled with incompatible glibc
-        """
-        assert not pep425tags.is_manylinux1_compatible()
-
-    @patch('setuptools.pep425tags.get_platform', lambda: 'arm6vl')
-    @patch('setuptools.glibc.have_compatible_glibc',
-           lambda major, minor: True)
-    def test_manylinux1_3(self):
-        """
-        Test that manylinux1 is disabled on arm6vl
-        """
-        assert not pep425tags.is_manylinux1_compatible()
-
-    @patch('setuptools.pep425tags.get_platform', lambda: 'linux_x86_64')
-    @patch('setuptools.glibc.have_compatible_glibc',
-           lambda major, minor: True)
-    @patch('sys.platform', 'linux2')
-    def test_manylinux1_tag_is_first(self):
-        """
-        Test that the more specific tag manylinux1 comes first.
-        """
-        groups = {}
-        for pyimpl, abi, arch in pep425tags.get_supported():
-            groups.setdefault((pyimpl, abi), []).append(arch)
-
-        for arches in groups.values():
-            if arches == ['any']:
-                continue
-            # Expect the most specific arch first:
-            if len(arches) == 3:
-                assert arches == ['manylinux1_x86_64', 'linux_x86_64', 'any']
-            else:
-                assert arches == ['manylinux1_x86_64', 'linux_x86_64']
diff --git a/setuptools/tests/test_register.py b/setuptools/tests/test_register.py
index 96114595..98605806 100644
--- a/setuptools/tests/test_register.py
+++ b/setuptools/tests/test_register.py
@@ -1,43 +1,22 @@
-import mock
-from distutils import log
-
-import pytest
-
 from setuptools.command.register import register
 from setuptools.dist import Distribution
+from setuptools.errors import RemovedCommandError
 
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 
-class TestRegisterTest:
-    def test_warns_deprecation(self):
-        dist = Distribution()
-
-        cmd = register(dist)
-        cmd.run_command = mock.Mock()
-        cmd.send_metadata = mock.Mock()
-        cmd.announce = mock.Mock()
-
-        cmd.run()
+import pytest
 
-        cmd.announce.assert_called_with(
-            "WARNING: Registering is deprecated, use twine to upload instead "
-            "(https://pypi.org/p/twine/)",
-            log.WARN
-        )
 
-    def test_warns_deprecation_when_raising(self):
+class TestRegister:
+    def test_register_exception(self):
+        """Ensure that the register command has been properly removed."""
         dist = Distribution()
+        dist.dist_files = [(mock.Mock(), mock.Mock(), mock.Mock())]
 
         cmd = register(dist)
-        cmd.run_command = mock.Mock()
-        cmd.send_metadata = mock.Mock()
-        cmd.send_metadata.side_effect = Exception
-        cmd.announce = mock.Mock()
 
-        with pytest.raises(Exception):
+        with pytest.raises(RemovedCommandError):
             cmd.run()
-
-        cmd.announce.assert_called_with(
-            "WARNING: Registering is deprecated, use twine to upload instead "
-            "(https://pypi.org/p/twine/)",
-            log.WARN
-        )
diff --git a/setuptools/tests/test_sdist.py b/setuptools/tests/test_sdist.py
index d2c4e0cf..0bea53df 100644
--- a/setuptools/tests/test_sdist.py
+++ b/setuptools/tests/test_sdist.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
 """sdist tests"""
 
+from __future__ import print_function, unicode_literals
+
 import os
-import shutil
 import sys
 import tempfile
 import unicodedata
@@ -50,7 +51,7 @@ def quiet():
 
 # Convert to POSIX path
 def posix(path):
-    if six.PY3 and not isinstance(path, str):
+    if not six.PY2 and not isinstance(path, str):
         return path.replace(os.sep.encode('ascii'), b'/')
     else:
         return path.replace(os.sep, '/')
@@ -89,30 +90,28 @@ fail_on_latin1_encoded_filenames = pytest.mark.xfail(
 )
 
 
+def touch(path):
+    path.write_text('', encoding='utf-8')
+
+
 class TestSdistTest:
-    def setup_method(self, method):
-        self.temp_dir = tempfile.mkdtemp()
-        with open(os.path.join(self.temp_dir, 'setup.py'), 'w') as f:
-            f.write(SETUP_PY)
+    @pytest.fixture(autouse=True)
+    def source_dir(self, tmpdir):
+        (tmpdir / 'setup.py').write_text(SETUP_PY, encoding='utf-8')
 
         # Set up the rest of the test package
-        test_pkg = os.path.join(self.temp_dir, 'sdist_test')
-        os.mkdir(test_pkg)
-        data_folder = os.path.join(self.temp_dir, "d")
-        os.mkdir(data_folder)
+        test_pkg = tmpdir / 'sdist_test'
+        test_pkg.mkdir()
+        data_folder = tmpdir / 'd'
+        data_folder.mkdir()
         # *.rst was not included in package_data, so c.rst should not be
         # automatically added to the manifest when not under version control
-        for fname in ['__init__.py', 'a.txt', 'b.txt', 'c.rst',
-                      os.path.join(data_folder, "e.dat")]:
-            # Just touch the files; their contents are irrelevant
-            open(os.path.join(test_pkg, fname), 'w').close()
-
-        self.old_cwd = os.getcwd()
-        os.chdir(self.temp_dir)
+        for fname in ['__init__.py', 'a.txt', 'b.txt', 'c.rst']:
+            touch(test_pkg / fname)
+        touch(data_folder / 'e.dat')
 
-    def teardown_method(self, method):
-        os.chdir(self.old_cwd)
-        shutil.rmtree(self.temp_dir)
+        with tmpdir.as_cwd():
+            yield
 
     def test_package_data_in_sdist(self):
         """Regression test for pull request #4: ensures that files listed in
@@ -175,14 +174,14 @@ class TestSdistTest:
         manifest = cmd.filelist.files
         assert 'setup.py' not in manifest
 
-    def test_defaults_case_sensitivity(self):
+    def test_defaults_case_sensitivity(self, tmpdir):
         """
         Make sure default files (README.*, etc.) are added in a case-sensitive
         way to avoid problems with packages built on Windows.
         """
 
-        open(os.path.join(self.temp_dir, 'readme.rst'), 'w').close()
-        open(os.path.join(self.temp_dir, 'SETUP.cfg'), 'w').close()
+        touch(tmpdir / 'readme.rst')
+        touch(tmpdir / 'SETUP.cfg')
 
         dist = Distribution(SETUP_ATTRS)
         # the extension deliberately capitalized for this test
@@ -230,10 +229,6 @@ class TestSdistTest:
         u_contents = contents.decode('UTF-8')
 
         # The manifest should contain the UTF-8 filename
-        if six.PY2:
-            fs_enc = sys.getfilesystemencoding()
-            filename = filename.decode(fs_enc)
-
         assert posix(filename) in u_contents
 
     @py3_only
@@ -334,7 +329,7 @@ class TestSdistTest:
             cmd.read_manifest()
 
         # The filelist should contain the UTF-8 filename
-        if six.PY3:
+        if not six.PY2:
             filename = filename.decode('utf-8')
         assert filename in cmd.filelist.files
 
@@ -374,7 +369,7 @@ class TestSdistTest:
     @fail_on_latin1_encoded_filenames
     def test_sdist_with_utf8_encoded_filename(self):
         # Test for #303.
-        dist = Distribution(SETUP_ATTRS)
+        dist = Distribution(self.make_strings(SETUP_ATTRS))
         dist.script_name = 'setup.py'
         cmd = sdist(dist)
         cmd.ensure_finalized()
@@ -388,7 +383,7 @@ class TestSdistTest:
         if sys.platform == 'darwin':
             filename = decompose(filename)
 
-        if six.PY3:
+        if not six.PY2:
             fs_enc = sys.getfilesystemencoding()
 
             if sys.platform == 'win32':
@@ -405,10 +400,19 @@ class TestSdistTest:
         else:
             assert filename in cmd.filelist.files
 
+    @classmethod
+    def make_strings(cls, item):
+        if isinstance(item, dict):
+            return {
+                key: cls.make_strings(value) for key, value in item.items()}
+        if isinstance(item, list):
+            return list(map(cls.make_strings, item))
+        return str(item)
+
     @fail_on_latin1_encoded_filenames
     def test_sdist_with_latin1_encoded_filename(self):
         # Test for #303.
-        dist = Distribution(SETUP_ATTRS)
+        dist = Distribution(self.make_strings(SETUP_ATTRS))
         dist.script_name = 'setup.py'
         cmd = sdist(dist)
         cmd.ensure_finalized()
@@ -421,7 +425,19 @@ class TestSdistTest:
         with quiet():
             cmd.run()
 
-        if six.PY3:
+        if six.PY2:
+            # Under Python 2 there seems to be no decoded string in the
+            # filelist.  However, due to decode and encoding of the
+            # file name to get utf-8 Manifest the latin1 maybe excluded
+            try:
+                # fs_enc should match how one is expect the decoding to
+                # be proformed for the manifest output.
+                fs_enc = sys.getfilesystemencoding()
+                filename.decode(fs_enc)
+                assert filename in cmd.filelist.files
+            except UnicodeDecodeError:
+                filename not in cmd.filelist.files
+        else:
             # not all windows systems have a default FS encoding of cp1252
             if sys.platform == 'win32':
                 # Latin-1 is similar to Windows-1252 however
@@ -436,18 +452,36 @@ class TestSdistTest:
                 # The Latin-1 filename should have been skipped
                 filename = filename.decode('latin-1')
                 filename not in cmd.filelist.files
-        else:
-            # Under Python 2 there seems to be no decoded string in the
-            # filelist.  However, due to decode and encoding of the
-            # file name to get utf-8 Manifest the latin1 maybe excluded
-            try:
-                # fs_enc should match how one is expect the decoding to
-                # be proformed for the manifest output.
-                fs_enc = sys.getfilesystemencoding()
-                filename.decode(fs_enc)
-                assert filename in cmd.filelist.files
-            except UnicodeDecodeError:
-                filename not in cmd.filelist.files
+
+    def test_pyproject_toml_in_sdist(self, tmpdir):
+        """
+        Check if pyproject.toml is included in source distribution if present
+        """
+        touch(tmpdir / 'pyproject.toml')
+        dist = Distribution(SETUP_ATTRS)
+        dist.script_name = 'setup.py'
+        cmd = sdist(dist)
+        cmd.ensure_finalized()
+        with quiet():
+            cmd.run()
+        manifest = cmd.filelist.files
+        assert 'pyproject.toml' in manifest
+
+    def test_pyproject_toml_excluded(self, tmpdir):
+        """
+        Check that pyproject.toml can excluded even if present
+        """
+        touch(tmpdir / 'pyproject.toml')
+        with open('MANIFEST.in', 'w') as mts:
+            print('exclude pyproject.toml', file=mts)
+        dist = Distribution(SETUP_ATTRS)
+        dist.script_name = 'setup.py'
+        cmd = sdist(dist)
+        cmd.ensure_finalized()
+        with quiet():
+            cmd.run()
+        manifest = cmd.filelist.files
+        assert 'pyproject.toml' not in manifest
 
 
 def test_default_revctrl():
diff --git a/setuptools/tests/test_setopt.py b/setuptools/tests/test_setopt.py
index 3fb04fb4..1b038954 100644
--- a/setuptools/tests/test_setopt.py
+++ b/setuptools/tests/test_setopt.py
@@ -15,7 +15,7 @@ class TestEdit:
     def parse_config(filename):
         parser = configparser.ConfigParser()
         with io.open(filename, encoding='utf-8') as reader:
-            (parser.read_file if six.PY3 else parser.readfp)(reader)
+            (parser.readfp if six.PY2 else parser.read_file)(reader)
         return parser
 
     @staticmethod
diff --git a/setuptools/tests/test_setuptools.py b/setuptools/tests/test_setuptools.py
index 5896a69a..08d263ae 100644
--- a/setuptools/tests/test_setuptools.py
+++ b/setuptools/tests/test_setuptools.py
@@ -4,7 +4,7 @@ import sys
 import os
 import distutils.core
 import distutils.cmd
-from distutils.errors import DistutilsOptionError, DistutilsPlatformError
+from distutils.errors import DistutilsOptionError
 from distutils.errors import DistutilsSetupError
 from distutils.core import Extension
 from distutils.version import LooseVersion
@@ -14,7 +14,6 @@ import pytest
 import setuptools
 import setuptools.dist
 import setuptools.depends as dep
-from setuptools import Feature
 from setuptools.depends import Require
 from setuptools.extern import six
 
@@ -108,6 +107,11 @@ class TestDepends:
         assert not req.is_present()
         assert not req.is_current()
 
+    @needs_bytecode
+    def test_require_present(self):
+        # In #1896, this test was failing for months with the only
+        # complaint coming from test runners (not end users).
+        # TODO: Evaluate if this code is needed at all.
         req = Require('Tests', None, 'tests', homepage="http://example.com")
         assert req.format is None
         assert req.attribute is None
@@ -211,86 +215,6 @@ class TestDistro:
             self.dist.exclude(package_dir=['q'])
 
 
-@pytest.mark.filterwarnings('ignore:Features are deprecated')
-class TestFeatures:
-    def setup_method(self, method):
-        self.req = Require('Distutils', '1.0.3', 'distutils')
-        self.dist = makeSetup(
-            features={
-                'foo': Feature(
-                    "foo", standard=True, require_features=['baz', self.req]),
-                'bar': Feature("bar", standard=True, packages=['pkg.bar'],
-                               py_modules=['bar_et'], remove=['bar.ext'],
-                               ),
-                'baz': Feature(
-                        "baz", optional=False, packages=['pkg.baz'],
-                        scripts=['scripts/baz_it'],
-                        libraries=[('libfoo', 'foo/foofoo.c')]
-                       ),
-                'dwim': Feature("DWIM", available=False, remove='bazish'),
-            },
-            script_args=['--without-bar', 'install'],
-            packages=['pkg.bar', 'pkg.foo'],
-            py_modules=['bar_et', 'bazish'],
-            ext_modules=[Extension('bar.ext', ['bar.c'])]
-        )
-
-    def testDefaults(self):
-        assert not Feature(
-            "test", standard=True, remove='x', available=False
-        ).include_by_default()
-        assert Feature("test", standard=True, remove='x').include_by_default()
-        # Feature must have either kwargs, removes, or require_features
-        with pytest.raises(DistutilsSetupError):
-            Feature("test")
-
-    def testAvailability(self):
-        with pytest.raises(DistutilsPlatformError):
-            self.dist.features['dwim'].include_in(self.dist)
-
-    def testFeatureOptions(self):
-        dist = self.dist
-        assert (
-            ('with-dwim', None, 'include DWIM') in dist.feature_options
-        )
-        assert (
-            ('without-dwim', None, 'exclude DWIM (default)')
-            in dist.feature_options
-        )
-        assert (
-            ('with-bar', None, 'include bar (default)') in dist.feature_options
-        )
-        assert (
-            ('without-bar', None, 'exclude bar') in dist.feature_options
-        )
-        assert dist.feature_negopt['without-foo'] == 'with-foo'
-        assert dist.feature_negopt['without-bar'] == 'with-bar'
-        assert dist.feature_negopt['without-dwim'] == 'with-dwim'
-        assert ('without-baz' not in dist.feature_negopt)
-
-    def testUseFeatures(self):
-        dist = self.dist
-        assert dist.with_foo == 1
-        assert dist.with_bar == 0
-        assert dist.with_baz == 1
-        assert ('bar_et' not in dist.py_modules)
-        assert ('pkg.bar' not in dist.packages)
-        assert ('pkg.baz' in dist.packages)
-        assert ('scripts/baz_it' in dist.scripts)
-        assert (('libfoo', 'foo/foofoo.c') in dist.libraries)
-        assert dist.ext_modules == []
-        assert dist.require_features == [self.req]
-
-        # If we ask for bar, it should fail because we explicitly disabled
-        # it on the command line
-        with pytest.raises(DistutilsOptionError):
-            dist.include_feature('bar')
-
-    def testFeatureWithInvalidRemove(self):
-        with pytest.raises(SystemExit):
-            makeSetup(features={'x': Feature('x', remove='y')})
-
-
 class TestCommandTests:
     def testTestIsCommand(self):
         test_cmd = makeSetup().get_command_obj('test')
diff --git a/setuptools/tests/test_test.py b/setuptools/tests/test_test.py
index faaa6ba9..892fd120 100644
--- a/setuptools/tests/test_test.py
+++ b/setuptools/tests/test_test.py
@@ -1,7 +1,8 @@
-# -*- coding: UTF-8 -*-
+# -*- coding: utf-8 -*-
 
 from __future__ import unicode_literals
 
+import mock
 from distutils import log
 import os
 
@@ -9,9 +10,10 @@ import pytest
 
 from setuptools.command.test import test
 from setuptools.dist import Distribution
+from setuptools.tests import ack_2to3
 
 from .textwrap import DALS
-from . import contexts
+
 
 SETUP_PY = DALS("""
     from setuptools import setup
@@ -73,6 +75,7 @@ def quiet_log():
 
 
 @pytest.mark.usefixtures('sample_test', 'quiet_log')
+@ack_2to3
 def test_test(capfd):
     params = dict(
         name='foo',
@@ -85,9 +88,7 @@ def test_test(capfd):
     dist.script_name = 'setup.py'
     cmd = test(dist)
     cmd.ensure_finalized()
-    # The test runner calls sys.exit
-    with contexts.suppress_exceptions(SystemExit):
-        cmd.run()
+    cmd.run()
     out, err = capfd.readouterr()
     assert out == 'Foo\n'
 
@@ -119,8 +120,57 @@ def test_tests_are_run_once(capfd):
     dist.script_name = 'setup.py'
     cmd = test(dist)
     cmd.ensure_finalized()
-    # The test runner calls sys.exit
-    with contexts.suppress_exceptions(SystemExit):
-        cmd.run()
+    cmd.run()
     out, err = capfd.readouterr()
     assert out == 'Foo\n'
+
+
+@pytest.mark.usefixtures('sample_test')
+@ack_2to3
+def test_warns_deprecation(capfd):
+    params = dict(
+        name='foo',
+        packages=['name', 'name.space', 'name.space.tests'],
+        namespace_packages=['name'],
+        test_suite='name.space.tests.test_suite',
+        use_2to3=True
+    )
+    dist = Distribution(params)
+    dist.script_name = 'setup.py'
+    cmd = test(dist)
+    cmd.ensure_finalized()
+    cmd.announce = mock.Mock()
+    cmd.run()
+    capfd.readouterr()
+    msg = (
+        "WARNING: Testing via this command is deprecated and will be "
+        "removed in a future version. Users looking for a generic test "
+        "entry point independent of test runner are encouraged to use "
+        "tox."
+    )
+    cmd.announce.assert_any_call(msg, log.WARN)
+
+
+@pytest.mark.usefixtures('sample_test')
+@ack_2to3
+def test_deprecation_stderr(capfd):
+    params = dict(
+        name='foo',
+        packages=['name', 'name.space', 'name.space.tests'],
+        namespace_packages=['name'],
+        test_suite='name.space.tests.test_suite',
+        use_2to3=True
+    )
+    dist = Distribution(params)
+    dist.script_name = 'setup.py'
+    cmd = test(dist)
+    cmd.ensure_finalized()
+    cmd.run()
+    out, err = capfd.readouterr()
+    msg = (
+        "WARNING: Testing via this command is deprecated and will be "
+        "removed in a future version. Users looking for a generic test "
+        "entry point independent of test runner are encouraged to use "
+        "tox.\n"
+    )
+    assert msg in err
diff --git a/setuptools/tests/test_upload.py b/setuptools/tests/test_upload.py
index 320c6959..7586cb26 100644
--- a/setuptools/tests/test_upload.py
+++ b/setuptools/tests/test_upload.py
@@ -1,213 +1,22 @@
-import mock
-import os
-import re
-
-from distutils import log
-from distutils.errors import DistutilsError
-
-import pytest
-
 from setuptools.command.upload import upload
 from setuptools.dist import Distribution
-from setuptools.extern import six
-
-
-def _parse_upload_body(body):
-    boundary = u'\r\n----------------GHSKFJDLGDS7543FJKLFHRE75642756743254'
-    entries = []
-    name_re = re.compile(u'^Content-Disposition: form-data; name="([^\"]+)"')
-
-    for entry in body.split(boundary):
-        pair = entry.split(u'\r\n\r\n')
-        if not len(pair) == 2:
-            continue
-
-        key, value = map(six.text_type.strip, pair)
-        m = name_re.match(key)
-        if m is not None:
-            key = m.group(1)
-
-        entries.append((key, value))
-
-    return entries
-
-
-@pytest.fixture
-def patched_upload(tmpdir):
-    class Fix:
-        def __init__(self, cmd, urlopen):
-            self.cmd = cmd
-            self.urlopen = urlopen
-
-        def __iter__(self):
-            return iter((self.cmd, self.urlopen))
-
-        def get_uploaded_metadata(self):
-            request = self.urlopen.call_args_list[0][0][0]
-            body = request.data.decode('utf-8')
-            entries = dict(_parse_upload_body(body))
-
-            return entries
+from setuptools.errors import RemovedCommandError
 
-    class ResponseMock(mock.Mock):
-        def getheader(self, name, default=None):
-            """Mocked getheader method for response object"""
-            return {
-                'content-type': 'text/plain; charset=utf-8',
-            }.get(name.lower(), default)
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 
-    with mock.patch('setuptools.command.upload.urlopen') as urlopen:
-        urlopen.return_value = ResponseMock()
-        urlopen.return_value.getcode.return_value = 200
-        urlopen.return_value.read.return_value = b''
-
-        content = os.path.join(str(tmpdir), "content_data")
-
-        with open(content, 'w') as f:
-            f.write("Some content")
-
-        dist = Distribution()
-        dist.dist_files = [('sdist', '3.7.0', content)]
-
-        cmd = upload(dist)
-        cmd.announce = mock.Mock()
-        cmd.username = 'user'
-        cmd.password = 'hunter2'
-
-        yield Fix(cmd, urlopen)
-
-
-class TestUploadTest:
-    def test_upload_metadata(self, patched_upload):
-        cmd, patch = patched_upload
-
-        # Set the metadata version to 2.1
-        cmd.distribution.metadata.metadata_version = '2.1'
-
-        # Run the command
-        cmd.ensure_finalized()
-        cmd.run()
-
-        # Make sure we did the upload
-        patch.assert_called_once()
-
-        # Make sure the metadata version is correct in the headers
-        entries = patched_upload.get_uploaded_metadata()
-        assert entries['metadata_version'] == '2.1'
-
-    def test_warns_deprecation(self):
-        dist = Distribution()
-        dist.dist_files = [(mock.Mock(), mock.Mock(), mock.Mock())]
-
-        cmd = upload(dist)
-        cmd.upload_file = mock.Mock()
-        cmd.announce = mock.Mock()
-
-        cmd.run()
+import pytest
 
-        cmd.announce.assert_called_once_with(
-            "WARNING: Uploading via this command is deprecated, use twine to "
-            "upload instead (https://pypi.org/p/twine/)",
-            log.WARN
-        )
 
-    def test_warns_deprecation_when_raising(self):
+class TestUpload:
+    def test_upload_exception(self):
+        """Ensure that the register command has been properly removed."""
         dist = Distribution()
         dist.dist_files = [(mock.Mock(), mock.Mock(), mock.Mock())]
 
         cmd = upload(dist)
-        cmd.upload_file = mock.Mock()
-        cmd.upload_file.side_effect = Exception
-        cmd.announce = mock.Mock()
-
-        with pytest.raises(Exception):
-            cmd.run()
-
-        cmd.announce.assert_called_once_with(
-            "WARNING: Uploading via this command is deprecated, use twine to "
-            "upload instead (https://pypi.org/p/twine/)",
-            log.WARN
-        )
-
-    @pytest.mark.parametrize('url', [
-        'https://example.com/a;parameter',    # Has parameters
-        'https://example.com/a?query',        # Has query
-        'https://example.com/a#fragment',     # Has fragment
-        'ftp://example.com',                  # Invalid scheme
-
-    ])
-    def test_upload_file_invalid_url(self, url, patched_upload):
-        patched_upload.urlopen.side_effect = Exception("Should not be reached")
-
-        cmd = patched_upload.cmd
-        cmd.repository = url
-
-        cmd.ensure_finalized()
-        with pytest.raises(AssertionError):
-            cmd.run()
-
-    def test_upload_file_http_error(self, patched_upload):
-        patched_upload.urlopen.side_effect = six.moves.urllib.error.HTTPError(
-            'https://example.com',
-            404,
-            'File not found',
-            None,
-            None
-        )
-
-        cmd = patched_upload.cmd
-        cmd.ensure_finalized()
 
-        with pytest.raises(DistutilsError):
+        with pytest.raises(RemovedCommandError):
             cmd.run()
-
-        cmd.announce.assert_any_call(
-            'Upload failed (404): File not found',
-            log.ERROR)
-
-    def test_upload_file_os_error(self, patched_upload):
-        patched_upload.urlopen.side_effect = OSError("Invalid")
-
-        cmd = patched_upload.cmd
-        cmd.ensure_finalized()
-
-        with pytest.raises(OSError):
-            cmd.run()
-
-        cmd.announce.assert_any_call('Invalid', log.ERROR)
-
-    @mock.patch('setuptools.command.upload.spawn')
-    def test_upload_file_gpg(self, spawn, patched_upload):
-        cmd, urlopen = patched_upload
-
-        cmd.sign = True
-        cmd.identity = "Alice"
-        cmd.dry_run = True
-        content_fname = cmd.distribution.dist_files[0][2]
-        signed_file = content_fname + '.asc'
-
-        with open(signed_file, 'wb') as f:
-            f.write("signed-data".encode('utf-8'))
-
-        cmd.ensure_finalized()
-        cmd.run()
-
-        # Make sure that GPG was called
-        spawn.assert_called_once_with([
-            "gpg", "--detach-sign", "--local-user", "Alice", "-a",
-            content_fname
-        ], dry_run=True)
-
-        # Read the 'signed' data that was transmitted
-        entries = patched_upload.get_uploaded_metadata()
-        assert entries['gpg_signature'] == 'signed-data'
-
-    def test_show_response_no_error(self, patched_upload):
-        # This test is just that show_response doesn't throw an error
-        # It is not really important what the printed response looks like
-        # in a deprecated command, but we don't want to introduce new
-        # errors when importing this function from distutils
-
-        patched_upload.cmd.show_response = True
-        patched_upload.cmd.ensure_finalized()
-        patched_upload.cmd.run()
diff --git a/setuptools/tests/test_virtualenv.py b/setuptools/tests/test_virtualenv.py
index d7b98c77..555273ae 100644
--- a/setuptools/tests/test_virtualenv.py
+++ b/setuptools/tests/test_virtualenv.py
@@ -13,6 +13,17 @@ from .test_easy_install import make_nspkg_sdist
 
 
 @pytest.fixture(autouse=True)
+def disable_requires_python(monkeypatch):
+    """
+    Disable Requires-Python on Python 2.7
+    """
+    if sys.version_info > (3,):
+        return
+
+    monkeypatch.setenv('PIP_IGNORE_REQUIRES_PYTHON', 'true')
+
+
+@pytest.fixture(autouse=True)
 def pytest_virtualenv_works(virtualenv):
     """
     pytest_virtualenv may not work. if it doesn't, skip these
@@ -46,10 +57,7 @@ def test_clean_env_install(bare_virtualenv):
     """
     Check setuptools can be installed in a clean environment.
     """
-    bare_virtualenv.run(' && '.join((
-        'cd {source}',
-        'python setup.py install',
-    )).format(source=SOURCE_DIR))
+    bare_virtualenv.run(['python', 'setup.py', 'install'], cd=SOURCE_DIR)
 
 
 def _get_pip_versions():
@@ -62,7 +70,7 @@ def _get_pip_versions():
             from urllib.request import urlopen
             from urllib.error import URLError
         except ImportError:
-            from urllib2 import urlopen, URLError # Python 2.7 compat
+            from urllib2 import urlopen, URLError  # Python 2.7 compat
 
         try:
             urlopen('https://pypi.org', timeout=1)
@@ -104,10 +112,9 @@ def test_pip_upgrade_from_source(pip_version, virtualenv):
     dist_dir = virtualenv.workspace
     # Generate source distribution / wheel.
     virtualenv.run(' && '.join((
-        'cd {source}',
         'python setup.py -q sdist -d {dist}',
         'python setup.py -q bdist_wheel -d {dist}',
-    )).format(source=SOURCE_DIR, dist=dist_dir))
+    )).format(dist=dist_dir), cd=SOURCE_DIR)
     sdist = glob.glob(os.path.join(dist_dir, '*.zip'))[0]
     wheel = glob.glob(os.path.join(dist_dir, '*.whl'))[0]
     # Then update from wheel.
@@ -116,14 +123,12 @@ def test_pip_upgrade_from_source(pip_version, virtualenv):
     virtualenv.run('pip install --no-cache-dir --upgrade ' + sdist)
 
 
-def test_test_command_install_requirements(bare_virtualenv, tmpdir):
+def _check_test_command_install_requirements(virtualenv, tmpdir):
     """
     Check the test command will install all required dependencies.
     """
-    bare_virtualenv.run(' && '.join((
-        'cd {source}',
-        'python setup.py develop',
-    )).format(source=SOURCE_DIR))
+    # Install setuptools.
+    virtualenv.run('python setup.py develop', cd=SOURCE_DIR)
 
     def sdist(distname, version):
         dist_path = tmpdir.join('%s-%s.tar.gz' % (distname, version))
@@ -174,19 +179,27 @@ def test_test_command_install_requirements(bare_virtualenv, tmpdir):
             open('success', 'w').close()
             '''))
     # Run test command for test package.
-    bare_virtualenv.run(' && '.join((
-        'cd {tmpdir}',
-        'python setup.py test -s test',
-    )).format(tmpdir=tmpdir))
+    virtualenv.run(
+        ['python', 'setup.py', 'test', '-s', 'test'], cd=str(tmpdir))
     assert tmpdir.join('success').check()
 
 
+def test_test_command_install_requirements(virtualenv, tmpdir):
+    # Ensure pip/wheel packages are installed.
+    virtualenv.run(
+        "python -c \"__import__('pkg_resources').require(['pip', 'wheel'])\"")
+    _check_test_command_install_requirements(virtualenv, tmpdir)
+
+
+def test_test_command_install_requirements_when_using_easy_install(
+        bare_virtualenv, tmpdir):
+    _check_test_command_install_requirements(bare_virtualenv, tmpdir)
+
+
 def test_no_missing_dependencies(bare_virtualenv):
     """
     Quick and dirty test to ensure all external dependencies are vendored.
     """
     for command in ('upload',):  # sorted(distutils.command.__all__):
-        bare_virtualenv.run(' && '.join((
-            'cd {source}',
-            'python setup.py {command} -h',
-        )).format(command=command, source=SOURCE_DIR))
+        bare_virtualenv.run(
+            ['python', 'setup.py', command, '-h'], cd=SOURCE_DIR)
diff --git a/setuptools/tests/test_wheel.py b/setuptools/tests/test_wheel.py
index e85a4a7e..f72ccbbf 100644
--- a/setuptools/tests/test_wheel.py
+++ b/setuptools/tests/test_wheel.py
@@ -18,6 +18,7 @@ import pytest
 
 from pkg_resources import Distribution, PathMetadata, PY_MAJOR
 from setuptools.extern.packaging.utils import canonicalize_name
+from setuptools.extern.packaging.tags import parse_tag
 from setuptools.wheel import Wheel
 
 from .contexts import tempdir
@@ -124,11 +125,12 @@ def flatten_tree(tree):
 
 
 def format_install_tree(tree):
-    return {x.format(
-        py_version=PY_MAJOR,
-        platform=get_platform(),
-        shlib_ext=get_config_var('EXT_SUFFIX') or get_config_var('SO'))
-            for x in tree}
+    return {
+        x.format(
+            py_version=PY_MAJOR,
+            platform=get_platform(),
+            shlib_ext=get_config_var('EXT_SUFFIX') or get_config_var('SO'))
+        for x in tree}
 
 
 def _check_wheel_install(filename, install_dir, install_tree_includes,
@@ -451,6 +453,35 @@ WHEEL_INSTALL_TESTS = (
     ),
 
     dict(
+        id='empty_namespace_package',
+        file_defs={
+            'foobar': {
+                '__init__.py':
+                    "__import__('pkg_resources').declare_namespace(__name__)",
+            },
+        },
+        setup_kwargs=dict(
+            namespace_packages=['foobar'],
+            packages=['foobar'],
+        ),
+        install_tree=flatten_tree({
+            'foo-1.0-py{py_version}.egg': [
+                'foo-1.0-py{py_version}-nspkg.pth',
+                {'EGG-INFO': [
+                    'PKG-INFO',
+                    'RECORD',
+                    'WHEEL',
+                    'namespace_packages.txt',
+                    'top_level.txt',
+                ]},
+                {'foobar': [
+                    '__init__.py',
+                ]},
+            ]
+        }),
+    ),
+
+    dict(
         id='data_in_package',
         file_defs={
             'foo': {
@@ -543,3 +574,12 @@ def test_wheel_no_dist_dir():
                 _check_wheel_install(wheel_path, install_dir, None,
                                      project_name,
                                      version, None)
+
+
+def test_wheel_is_compatible(monkeypatch):
+    def sys_tags():
+        for t in parse_tag('cp36-cp36m-manylinux1_x86_64'):
+            yield t
+    monkeypatch.setattr('setuptools.wheel.sys_tags', sys_tags)
+    assert Wheel(
+        'onnxruntime-0.1.2-cp36-cp36m-manylinux1_x86_64.whl').is_compatible()
diff --git a/setuptools/wheel.py b/setuptools/wheel.py
index e11f0a1d..ec1106a7 100644
--- a/setuptools/wheel.py
+++ b/setuptools/wheel.py
@@ -1,6 +1,7 @@
 """Wheels support."""
 
 from distutils.util import get_platform
+from distutils import log
 import email
 import itertools
 import os
@@ -11,9 +12,9 @@ import zipfile
 import pkg_resources
 import setuptools
 from pkg_resources import parse_version
+from setuptools.extern.packaging.tags import sys_tags
 from setuptools.extern.packaging.utils import canonicalize_name
 from setuptools.extern.six import PY3
-from setuptools import pep425tags
 from setuptools.command.egg_info import write_requirements
 
 
@@ -76,7 +77,8 @@ class Wheel:
 
     def is_compatible(self):
         '''Is the wheel is compatible with the current platform?'''
-        supported_tags = pep425tags.get_supported()
+        supported_tags = set(
+            (t.interpreter, t.abi, t.platform) for t in sys_tags())
         return next((True for t in self.tags() if t in supported_tags), False)
 
     def egg_name(self):
@@ -162,11 +164,17 @@ class Wheel:
                 extras_require=extras_require,
             ),
         )
-        write_requirements(
-            setup_dist.get_command_obj('egg_info'),
-            None,
-            os.path.join(egg_info, 'requires.txt'),
-        )
+        # Temporarily disable info traces.
+        log_threshold = log._global_log.threshold
+        log.set_threshold(log.WARN)
+        try:
+            write_requirements(
+                setup_dist.get_command_obj('egg_info'),
+                None,
+                os.path.join(egg_info, 'requires.txt'),
+            )
+        finally:
+            log.set_threshold(log_threshold)
 
     @staticmethod
     def _move_data_entries(destination_eggdir, dist_data):
@@ -206,6 +214,8 @@ class Wheel:
             for mod in namespace_packages:
                 mod_dir = os.path.join(destination_eggdir, *mod.split('.'))
                 mod_init = os.path.join(mod_dir, '__init__.py')
-                if os.path.exists(mod_dir) and not os.path.exists(mod_init):
+                if not os.path.exists(mod_dir):
+                    os.mkdir(mod_dir)
+                if not os.path.exists(mod_init):
                     with open(mod_init, 'w') as fp:
                         fp.write(NAMESPACE_PACKAGE_INIT)
diff --git a/tests/manual_test.py b/tests/manual_test.py
deleted file mode 100644
index 99db4b01..00000000
--- a/tests/manual_test.py
+++ /dev/null
@@ -1,100 +0,0 @@
-#!/usr/bin/env python
-
-import sys
-import os
-import shutil
-import tempfile
-import subprocess
-from distutils.command.install import INSTALL_SCHEMES
-from string import Template
-
-from setuptools.extern.six.moves import urllib
-
-
-def _system_call(*args):
-    assert subprocess.call(args) == 0
-
-
-def tempdir(func):
-    def _tempdir(*args, **kwargs):
-        test_dir = tempfile.mkdtemp()
-        old_dir = os.getcwd()
-        os.chdir(test_dir)
-        try:
-            return func(*args, **kwargs)
-        finally:
-            os.chdir(old_dir)
-            shutil.rmtree(test_dir)
-
-    return _tempdir
-
-
-SIMPLE_BUILDOUT = """\
-[buildout]
-
-parts = eggs
-
-[eggs]
-recipe = zc.recipe.egg
-
-eggs =
-    extensions
-"""
-
-BOOTSTRAP = 'http://downloads.buildout.org/1/bootstrap.py'
-PYVER = sys.version.split()[0][:3]
-
-_VARS = {'base': '.',
-         'py_version_short': PYVER}
-
-scheme = 'nt' if sys.platform == 'win32' else 'unix_prefix'
-PURELIB = INSTALL_SCHEMES[scheme]['purelib']
-
-
-@tempdir
-def test_virtualenv():
-    """virtualenv with setuptools"""
-    purelib = os.path.abspath(Template(PURELIB).substitute(**_VARS))
-    _system_call('virtualenv', '--no-site-packages', '.')
-    _system_call('bin/easy_install', 'setuptools==dev')
-    # linux specific
-    site_pkg = os.listdir(purelib)
-    site_pkg.sort()
-    assert 'setuptools' in site_pkg[0]
-    easy_install = os.path.join(purelib, 'easy-install.pth')
-    with open(easy_install) as f:
-        res = f.read()
-    assert 'setuptools' in res
-
-
-@tempdir
-def test_full():
-    """virtualenv + pip + buildout"""
-    _system_call('virtualenv', '--no-site-packages', '.')
-    _system_call('bin/easy_install', '-q', 'setuptools==dev')
-    _system_call('bin/easy_install', '-qU', 'setuptools==dev')
-    _system_call('bin/easy_install', '-q', 'pip')
-    _system_call('bin/pip', 'install', '-q', 'zc.buildout')
-
-    with open('buildout.cfg', 'w') as f:
-        f.write(SIMPLE_BUILDOUT)
-
-    with open('bootstrap.py', 'w') as f:
-        f.write(urllib.request.urlopen(BOOTSTRAP).read())
-
-    _system_call('bin/python', 'bootstrap.py')
-    _system_call('bin/buildout', '-q')
-    eggs = os.listdir('eggs')
-    eggs.sort()
-    assert len(eggs) == 3
-    assert eggs[1].startswith('setuptools')
-    del eggs[1]
-    assert eggs == [
-        'extensions-0.3-py2.6.egg',
-        'zc.recipe.egg-1.2.2-py2.6.egg',
-    ]
-
-
-if __name__ == '__main__':
-    test_virtualenv()
-    test_full()
diff --git a/tools/finalize.py b/tools/finalize.py
new file mode 100644
index 00000000..98b06c07
--- /dev/null
+++ b/tools/finalize.py
@@ -0,0 +1,81 @@
+"""
+Finalize the repo for a release. Invokes towncrier and bumpversion.
+"""
+
+__requires__ = ['bump2version', 'towncrier']
+
+
+import subprocess
+import pathlib
+import re
+import sys
+
+
+def release_kind():
+    """
+    Determine which release to make based on the files in the
+    changelog.
+    """
+    # use min here as 'major' < 'minor' < 'patch'
+    return min(
+        'major' if 'breaking' in file.name else
+        'minor' if 'change' in file.name else
+        'patch'
+        for file in pathlib.Path('changelog.d').iterdir()
+    )
+
+
+bump_version_command = [
+    sys.executable,
+    '-m', 'bumpversion',
+    release_kind(),
+]
+
+
+def get_version():
+    cmd = bump_version_command + ['--dry-run', '--verbose']
+    out = subprocess.check_output(cmd, text=True)
+    return re.search('^new_version=(.*)', out, re.MULTILINE).group(1)
+
+
+def update_changelog():
+    cmd = [
+        sys.executable, '-m',
+        'towncrier',
+        '--version', get_version(),
+        '--yes',
+    ]
+    subprocess.check_call(cmd)
+
+
+def bump_version():
+    cmd = bump_version_command + ['--allow-dirty']
+    subprocess.check_call(cmd)
+
+
+def ensure_config():
+    """
+    Double-check that Git has an e-mail configured.
+    """
+    subprocess.check_output(['git', 'config', 'user.email'])
+
+
+def check_changes():
+    """
+    Verify that all of the files in changelog.d have the appropriate
+    names.
+    """
+    allowed = 'deprecation', 'breaking', 'change', 'doc', 'misc'
+    assert all(
+        any(key in file.name for key in allowed)
+        for file in pathlib.Path('changelog.d').iterdir()
+        if file.name != '.gitignore'
+    )
+
+
+if __name__ == '__main__':
+    print("Cutting release at", get_version())
+    ensure_config()
+    check_changes()
+    update_changelog()
+    bump_version()
diff --git a/tools/tox_pip.py b/tools/tox_pip.py
new file mode 100644
index 00000000..9fe4f905
--- /dev/null
+++ b/tools/tox_pip.py
@@ -0,0 +1,82 @@
+import os
+import subprocess
+import sys
+import re
+
+
+def remove_setuptools():
+    """
+    Remove setuptools from the current environment.
+    """
+    print("Removing setuptools")
+    cmd = [sys.executable, '-m', 'pip', 'uninstall', '-y', 'setuptools']
+    # set cwd to something other than '.' to avoid detecting
+    # '.' as the installed package.
+    subprocess.check_call(cmd, cwd='.tox')
+
+
+def bootstrap():
+    print("Running bootstrap")
+    cmd = [sys.executable, '-m', 'bootstrap']
+    subprocess.check_call(cmd)
+
+
+def is_install_self(args):
+    """
+    Do the args represent an install of .?
+    """
+    def strip_extras(arg):
+        match = re.match(r'(.*)?\[.*\]$', arg)
+        return match.group(1) if match else arg
+
+    return (
+        'install' in args
+        and any(
+            arg in ['.', os.getcwd()]
+            for arg in map(strip_extras, args)
+        )
+    )
+
+
+def pip(*args):
+    cmd = [sys.executable, '-m', 'pip'] + list(args)
+    return subprocess.check_call(cmd)
+
+
+def test_dependencies():
+    from ConfigParser import ConfigParser
+
+    def clean(dep):
+        spec, _, _ = dep.partition('#')
+        return spec.strip()
+
+    parser = ConfigParser()
+    parser.read('setup.cfg')
+    raw = parser.get('options.extras_require', 'tests').split('\n')
+    return filter(None, map(clean, raw))
+
+
+def disable_python_requires():
+    """
+    On Python 2, install the dependencies that are selective
+    on Python version while honoring REQUIRES_PYTHON, then
+    disable REQUIRES_PYTHON so that pip can install this
+    checkout of setuptools.
+    """
+    pip('install', *test_dependencies())
+    os.environ['PIP_IGNORE_REQUIRES_PYTHON'] = 'true'
+
+
+def run(args):
+    os.environ['PIP_USE_PEP517'] = 'true'
+
+    if is_install_self(args):
+        remove_setuptools()
+        bootstrap()
+        sys.version_info > (3,) or disable_python_requires()
+
+    pip(*args)
+
+
+if __name__ == '__main__':
+    run(sys.argv[1:])
diff --git a/tox.ini b/tox.ini
index e0eef95a..aa99e283 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,26 +1,32 @@
-# Note: Run "python bootstrap.py" before running Tox, to generate metadata.
-#
 # To run Tox against all supported Python interpreters, you can set:
 #
-# export TOXENV='py27,py3{4,5,6},pypy,pypy3'
+# export TOXENV='py3{5,6,7,8},pypy,pypy3'
 
 [tox]
 envlist=python
+minversion = 3.2
+requires =
+	tox-pip-version >= 0.0.6
+	# workaround for #1998
+	virtualenv < 20
+
+[helpers]
+# Custom pip behavior
+pip = python {toxinidir}/tools/tox_pip.py
 
 [testenv]
-deps=-rtests/requirements.txt
-# Changed from default (`python -m pip ...`)
-# to prevent the current working directory
-# from being added to `sys.path`.
-install_command=python -c 'import sys; sys.path.remove(""); from pkg_resources import load_entry_point; load_entry_point("pip", "console_scripts", "pip")()' install {opts} {packages}
-# Same as above.
-list_dependencies_command={envbindir}/pip freeze --all
-setenv=COVERAGE_FILE={toxworkdir}/.coverage.{envname}
+pip_version = pip
+install_command = {[helpers]pip} install {opts} {packages}
+list_dependencies_command = {[helpers]pip} freeze --all
+setenv =
+	COVERAGE_FILE={toxworkdir}/.coverage.{envname}
 # TODO: The passed environment variables came from copying other tox.ini files
 # These should probably be individually annotated to explain what needs them.
-passenv=APPDATA HOMEDRIVE HOMEPATH windir APPVEYOR APPVEYOR_* CI CODECOV_* TRAVIS TRAVIS_* NETWORK_REQUIRED
+passenv=APPDATA HOMEDRIVE HOMEPATH windir Program* CommonProgram* VS* APPVEYOR APPVEYOR_* CI CODECOV_* TRAVIS TRAVIS_* NETWORK_REQUIRED
 commands=pytest --cov-config={toxinidir}/tox.ini --cov-report= {posargs}
 usedevelop=True
+extras =
+	tests
 
 
 [testenv:coverage]
@@ -40,12 +46,12 @@ skip_install=True
 commands=codecov -X gcov --file {toxworkdir}/coverage.xml
 
 [testenv:docs]
-deps = -r{toxinidir}/docs/requirements.txt
-skip_install=True
+extras =
+        docs
+        testing
+changedir = docs
 commands =
-    python {toxinidir}/bootstrap.py
-    sphinx-build -W -b html -d {envtmpdir}/doctrees docs docs/build/html
-    sphinx-build -W -b man -d {envtmpdir}/doctrees docs docs/build/man
+        python -m sphinx . {toxinidir}/build/html
 
 [coverage:run]
 source=
@@ -53,3 +59,31 @@ source=
 	setuptools
 omit=
 	*/_vendor/*
+
+[testenv:finalize]
+skip_install = True
+deps =
+	towncrier
+	bump2version
+passenv = *
+commands =
+	python tools/finalize.py
+
+[testenv:release]
+skip_install = True
+deps =
+	wheel
+	twine[keyring]>=1.13
+	path
+	jaraco.tidelift
+passenv =
+	TWINE_PASSWORD
+	TIDELIFT_TOKEN
+setenv =
+	TWINE_USERNAME = {env:TWINE_USERNAME:__token__}
+commands =
+	python -m bootstrap
+	python -c "import path; path.Path('dist').rmtree_p()"
+	python setup.py release
+	python -m twine upload dist/*
+	python -m jaraco.tidelift.publish-release-notes