do not strip empty sections in `extras_require`

2 files changed, 20 insertions, 0 deletions

diff --git a/setuptools/dist.py b/setuptools/dist.py
index 0787261e..dfe700bd 100644
--- a/setuptools/dist.py
+++ b/setuptools/dist.py
@@ -369,6 +369,8 @@ class Distribution(Distribution_parse_config_files, _Distribution):
         spec_ext_reqs = getattr(self, 'extras_require', None) or {}
         self._tmp_extras_require = defaultdict(list)
         for section, v in spec_ext_reqs.items():
+            # Do not strip empty sections.
+            self._tmp_extras_require[section]
             for r in pkg_resources.parse_requirements(v):
                 suffix = self._suffix_for(r)
                 self._tmp_extras_require[section + suffix].append(r)
diff --git a/setuptools/tests/test_egg_info.py b/setuptools/tests/test_egg_info.py
index d9d4ec3b..9ea7cdce 100644
--- a/setuptools/tests/test_egg_info.py
+++ b/setuptools/tests/test_egg_info.py
@@ -274,6 +274,8 @@ class TestEggInfo(object):
         with open(requires_txt) as fp:
             install_requires = fp.read()
         expected_requires = DALS('''
+             [extra]
+
              [extra:{marker}]
              barbazquux[test]
              ''').format(marker=self.mismatch_marker_alternate)
@@ -306,6 +308,8 @@ class TestEggInfo(object):
         with open(requires_txt) as fp:
             install_requires = fp.read()
         expected_requires = DALS('''
+             [extra]
+
              [extra:{marker}]
              barbazquux
              ''').format(marker=self.mismatch_marker_alternate)
@@ -328,6 +332,20 @@ class TestEggInfo(object):
             self._run_install_command(tmpdir_cwd, env)
         assert glob.glob(os.path.join(env.paths['lib'], 'barbazquux*')) == []
 
+    def test_extras_require_with_empty_section(self, tmpdir_cwd, env):
+        tmpl = 'extras_require={{"empty": []}},'
+        req = tmpl.format(marker=self.invalid_marker)
+        self._setup_script_with_requires(req)
+        self._run_install_command(tmpdir_cwd, env)
+        egg_info_dir = self._find_egg_info_files(env.paths['lib']).base
+        requires_txt = os.path.join(egg_info_dir, 'requires.txt')
+        with open(requires_txt) as fp:
+            install_requires = fp.read()
+        expected_requires = DALS('''
+             [empty]
+             ''').format(marker=self.mismatch_marker_alternate)
+        assert install_requires.lstrip() == expected_requires
+
     def test_python_requires_egg_info(self, tmpdir_cwd, env):
         self._setup_script_with_requires(
             """python_requires='>=2.7.12',""")