Disable nspkg.pth behavior on Python 3.3+. Fixes #805 and fixes pypa/pip#1924.

CHANGES.rst

@@ -2,6 +2,12 @@
 CHANGES
 =======
 
+v28.1.0
+-------
+
+* #805: Disable ``-nspkg.pth`` behavior on Python 3.3+ where
+  PEP-420 functionality is adequate. Fixes pip #1924.
+
 v28.0.0
 -------
 

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)",