[Python-Dev] weird bug in test_winreg

[Guido van Rossum]

> I just noticed a weird traceback in test_winreg.  When I import
> test.autotest on Windows, I get a "test failed" notice for
> test_winreg.  When I run it by itself the test succeeds.  But when I
> first import test.autotest and then import test.test_winreg (which
> should rerun the latter, since test.regrtest unloads all test modules
> after they have run), I get an AttributeError telling me that 'None'
> object has no attribute 'get'.  This is in encodings.__init__.py in
> the first call to _cache.get() in search_function.  Somehow this is
> called by SetValueEx() in WriteTestData() in test/test_winreg.py.  But
> inspection of the encodings module shows that _cache is {}, not None,
> and the source shows no evidence of how this could have happened.

I may have sounded confused: the problem is not caused by the
reload().  The test fails the first time around when run by
test.autotest.  My suspicion is that another test somehow overwrites
encodings._cache?

--Guido van Rossum (home page: http://www.python.org/~guido/)