Merge suppression of namespace handling when PEP-420 can handle namespace packages.

CHANGES.rst

@@ -8,6 +8,9 @@ v28.2.0
 * #809: In ``find_packages()``, restore support for excluding
   a parent package without excluding a child package.
 
+* #805: Disable ``-nspkg.pth`` behavior on Python 3.3+ where
+  PEP-420 functionality is adequate. Fixes pip #1924.
+
 v28.1.0
 -------
 

setup.cfg

 [bumpversion]
-current_version = 28.1.0
+current_version = 28.2.0
 commit = True
 tag = True
 

setup.py

@@ -88,7 +88,7 @@ def pypi_link(pkg_filename):
 
 setup_params = dict(
     name="setuptools",
-    version="28.1.0",
+    version="28.2.0",
     description="Easily download, build, install, upgrade, and uninstall "
         "Python packages",
     author="Python Packaging Authority",

setuptools/command/install_egg_info.py

@@ -82,9 +82,10 @@ class install_egg_info(Command):
 
     _nspkg_tmpl = (
         "import sys, types, os",
+        "pep420 = sys.version_info > (3, 3)",
         "p = os.path.join(sys._getframe(1).f_locals['sitedir'], *%(pth)r)",
         "ie = os.path.exists(os.path.join(p,'__init__.py'))",
-        "m = not ie and "
+        "m = not ie and not pep420 and "
             "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)",