Add support for PEP 420 namespace packages to find_packages()

On Python 3.3+, `find_packages()` now considers any subdirectory of the
start directory that's not a regular package (i.e., that doesn't have an
`__init__.py`) to be a namespace package.

The other way this supports PEP 420 is by making sure `__pycache__`
directories are never added to the list of packages.

Fixes issue #97

2 files changed, 42 insertions, 1 deletions

diff --git a/setuptools/__init__.py b/setuptools/__init__.py
index a96e4c9d..86afab63 100644
--- a/setuptools/__init__.py
+++ b/setuptools/__init__.py
@@ -56,7 +56,10 @@ def find_packages(where='.', exclude=(), include=()):
             looks_like_package = (
                 '.' not in name
                 and os.path.isdir(fn)
-                and os.path.isfile(os.path.join(fn, '__init__.py'))
+                and (
+                    os.path.isfile(os.path.join(fn, '__init__.py'))
+                    or sys.version_info[:2] >= (3, 3)  # PEP 420
+                )
             )
             if looks_like_package:
                 pkg_name = prefix + name
diff --git a/setuptools/tests/test_find_packages.py b/setuptools/tests/test_find_packages.py
index c50309d2..abb0dd61 100644
--- a/setuptools/tests/test_find_packages.py
+++ b/setuptools/tests/test_find_packages.py
@@ -1,12 +1,16 @@
 """Tests for setuptools.find_packages()."""
 import os
 import shutil
+import sys
 import tempfile
 import unittest
 
 from setuptools import find_packages
 
 
+PEP420 = sys.version_info[:2] >= (3, 3)
+
+
 class TestFindPackages(unittest.TestCase):
 
     def setUp(self):
@@ -58,6 +62,7 @@ class TestFindPackages(unittest.TestCase):
         fp.close()
         return path
 
+    @unittest.skipIf(PEP420, 'Not a PEP 420 env')
     def test_regular_package(self):
         self._touch('__init__.py', self.pkg_dir)
         packages = find_packages(self.dist_dir)
@@ -80,3 +85,36 @@ class TestFindPackages(unittest.TestCase):
         self._touch('file.dat', data_dir)
         packages = find_packages(self.dist_dir)
         self.assertTrue('pkg.some.data' not in packages)
+
+    @unittest.skipIf(not PEP420, 'PEP 420 only')
+    def test_pep420_ns_package(self):
+        packages = find_packages(
+            self.dist_dir, include=['pkg*'], exclude=['pkg.subpkg.assets'])
+        self.assertEqual(packages, ['pkg', 'pkg.nspkg', 'pkg.subpkg'])
+
+    @unittest.skipIf(not PEP420, 'PEP 420 only')
+    def test_pep420_ns_package_no_includes(self):
+        packages = find_packages(
+            self.dist_dir, exclude=['pkg.subpkg.assets'])
+        self.assertEqual(packages, ['docs', 'pkg', 'pkg.nspkg', 'pkg.subpkg'])
+
+    @unittest.skipIf(not PEP420, 'PEP 420 only')
+    def test_pep420_ns_package_no_includes_or_excludes(self):
+        packages = find_packages(self.dist_dir)
+        expected = [
+            'docs', 'pkg', 'pkg.nspkg', 'pkg.subpkg', 'pkg.subpkg.assets']
+        self.assertEqual(packages, expected)
+
+    @unittest.skipIf(not PEP420, 'PEP 420 only')
+    def test_regular_package_with_nested_pep420_ns_packages(self):
+        self._touch('__init__.py', self.pkg_dir)
+        packages = find_packages(
+            self.dist_dir, exclude=['docs', 'pkg.subpkg.assets'])
+        self.assertEqual(packages, ['pkg', 'pkg.nspkg', 'pkg.subpkg'])
+
+    @unittest.skipIf(not PEP420, 'PEP 420 only')
+    def test_pep420_ns_package_no_non_package_dirs(self):
+        shutil.rmtree(self.docs_dir)
+        shutil.rmtree(os.path.join(self.dist_dir, 'pkg/subpkg/assets'))
+        packages = find_packages(self.dist_dir)
+        self.assertEqual(packages, ['pkg', 'pkg.nspkg', 'pkg.subpkg'])