On Aug 19, 2016 6:46 PM, Chris Angelico <ros...@gmail.com> wrote:
>
> On Sat, Aug 20, 2016 at 2:25 AM, Steve Dower <steve.do...@python.org> wrote:
> > On 19Aug2016 0910, Chris Angelico wrote:
> >>
> >> On Sat, Aug 20, 2016 at 1:26 AM, Steve Dower <steve.do...@python.org>
> >> wrote:
> >>>
> >>> Check any .pth files you can find. I suspect mpl_toolkits has some magic
> >>> in
> >>> it to make the namespace package work on 2.7.
> >>
> >>
> >> $ cat
> >> /usr/local/lib/python3.6/site-packages/matplotlib-1.5.1-py3.6-nspkg.pth
> >> import sys, types, os;p =
> >> os.path.join(sys._getframe(1).f_locals['sitedir'],
> >> *('mpl_toolkits',));ie =
> >> os.path.exists(os.path.join(p,'__init__.py'));m = not ie and
> >> sys.modules.setdefault('mpl_toolkits',
> >> types.ModuleType('mpl_toolkits'));mp = (m or []) and
> >> m.__dict__.setdefault('__path__',[]);(p not in mp) and mp.append(p)
> >>
> >> Is it possible that that's the cause? And if so, should "python -I"
> >> remove /usr/local/lib/python3.6/site-packages from sys.path?
> >
> >
> > That explains the extra modules - types.py imports collections and
> > collections.abc, which would seem to account for the rest.
> >
> > I'm not sure whether that's causing the problem or not, but temporarily
> > renaming that pth file so it isn't picked up may help you track down the
> > test issue.
>
> Sure enough, that did fix the problem - that is to say, renaming it
> did allow test_site to pass. Thanks!
>
> > "python -S" is the only way to avoid .pth files, but that's a pretty heavy
> > hammer.
>
> Hmmmmmmm. So the question is, what is this test testing? For
> reference, here's the code:
>
> class StartupImportTests(unittest.TestCase):
>
> def test_startup_imports(self):
> # This tests checks which modules are loaded by Python when it
> # initially starts upon startup.
> popen = subprocess.Popen([sys.executable, '-I', '-v', '-c',
> 'import sys; print(set(sys.modules))'],
> stdout=subprocess.PIPE,
> stderr=subprocess.PIPE)
> stdout, stderr = popen.communicate()
> stdout = stdout.decode('utf-8')
> stderr = stderr.decode('utf-8')
> modules = eval(stdout)
>
> self.assertIn('site', modules)
>
> # http://bugs.python.org/issue19205
> re_mods = {'re', '_sre', 'sre_compile', 'sre_constants', 'sre_parse'}
> # _osx_support uses the re module in many placs
> if sys.platform != 'darwin':
> self.assertFalse(modules.intersection(re_mods), stderr)
> # http://bugs.python.org/issue9548
> self.assertNotIn('locale', modules, stderr)
> if sys.platform != 'darwin':
> # http://bugs.python.org/issue19209
> self.assertNotIn('copyreg', modules, stderr)
> # http://bugs.python.org/issue19218>
> collection_mods = {'_collections', 'collections', 'functools',
> 'heapq', 'itertools', 'keyword', 'operator',
> 'reprlib', 'types', 'weakref'
> }.difference(sys.builtin_module_names)
> self.assertFalse(modules.intersection(collection_mods), stderr)
>
>
> It asserts that 'site' is in the list of loaded modules, so simply
> adding '-S' to the subpython parameters doesn't work. But this test,
> as written, depends on the behaviour of arbitrary third-party modules
> installed with pip, which seems wrong for a standard library test.
> AIUI this is trying to catch changes that accidentally cause large
> modules to be loaded on startup, correct? Which is all well and good,
> but Python shouldn't have test failures due to matplotlib being
> installed.
>
> I see two (or three) ways to deal with this.
>
> 1) Declare it a bug in matplotlib, and demand that .pth files not
> import anything that wouldn't otherwise be imported.
>
> 2) Change the test to add '-S' and remove the assertion about 'site'
> being present; this means that site.py itself is no longer covered by
> the test.
>
> 3) Accept the status quo: this test can fail if .pth files are present.
>
4) split the test in two: one running with -S to check no collections, (and for *not* site.py). The other without -S, and check for site.py.
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