fix test runner and pyximport in Py 2.7.9 and 3.4+: setuptools replaces...

fix test runner and pyximport in Py 2.7.9 and 3.4+: setuptools replaces "distutils.dist.Distribution" *after* we import it, which then breaks the input validation in "distutils.cmd"

pyximport/pyxbuild.py

@@ -6,7 +6,6 @@ out_fname = pyx_to_dll("foo.pyx")
 import os
 import sys
 
-from distutils.dist import Distribution
 from distutils.errors import DistutilsArgError, DistutilsError, CCompilerError
 from distutils.extension import Extension
 from distutils.util import grok_environment_error
@@ -67,9 +66,12 @@ def pyx_to_dll(filename, ext = None, force_rebuild = 0,
     if HAS_CYTHON and build_in_temp:
         args.append("--pyrex-c-in-temp")
     sargs = setup_args.copy()
-    sargs.update(
-        {"script_name": None,
-         "script_args": args + script_args} )
+    sargs.update({
+        "script_name": None,
+        "script_args": args + script_args,
+    })
+    # late import, in case setuptools replaced it
+    from distutils.dist import Distribution
     dist = Distribution(sargs)
     if not dist.ext_modules:
         dist.ext_modules = []

runtests.py

@@ -71,14 +71,19 @@ except NameError:
 WITH_CYTHON = True
 CY3_DIR = None
 
-from distutils.dist import Distribution
 from distutils.core import Extension
 from distutils.command.build_ext import build_ext as _build_ext
 from distutils import sysconfig
-distutils_distro = Distribution()
 
 
-if sys.platform == 'win32':
+def get_distutils_distro(_cache=[]):
+    if _cache:
+        return _cache[0]
+    # late import to accomodate for setuptools override
+    from distutils.dist import Distribution
+    distutils_distro = Distribution()
+
+    if sys.platform == 'win32':
         # TODO: Figure out why this hackery (see http://thread.gmane.org/gmane.comp.python.cython.devel/8280/).
         config_files = distutils_distro.find_config_files()
         try: config_files.remove('setup.cfg')
@@ -89,6 +94,9 @@ if sys.platform == 'win32':
         try: cfgfiles.remove('setup.cfg')
         except ValueError: pass
         distutils_distro.parse_config_files(cfgfiles)
+    _cache.append(distutils_distro)
+    return distutils_distro
+
 
 EXT_DEP_MODULES = {
     'tag:numpy' : 'numpy',
@@ -802,7 +810,7 @@ class CythonCompileTestCase(unittest.TestCase):
         cwd = os.getcwd()
         os.chdir(workdir)
         try:
-            build_extension = build_ext(distutils_distro)
+            build_extension = build_ext(get_distutils_distro())
             build_extension.include_dirs = INCLUDE_DIRS[:]
             if incdir:
                 build_extension.include_dirs.append(incdir)