Metaclass problem on Python 3.2

[Dirkjan Ochtman]

This has been happening for a while now, in both 3.8.0 and 4.0.1:

Traceback (most recent call last):
  File "setup.py", line 138, in <module>
    **extra)
  File "/usr/lib64/python3.2/distutils/core.py", line 148, in setup
    dist.run_commands()
  File "/usr/lib64/python3.2/distutils/dist.py", line 917, in run_commands
    self.run_command(cmd)
  File "/usr/lib64/python3.2/distutils/dist.py", line 936, in run_command
    cmd_obj.run()
  File "/usr/lib64/python3.2/site-packages/setuptools/command/test.py", line 137, in run
    self.with_project_on_sys_path(self.run_tests)
  File "/usr/lib64/python3.2/site-packages/setuptools/command/test.py", line 117, in with_project_on_sys_path
    func()
  File "/usr/lib64/python3.2/site-packages/setuptools/command/test.py", line 146, in run_tests
    testLoader = loader_class()
  File "/usr/lib64/python3.2/unittest/main.py", line 123, in __init__
    self.parseArgs(argv)
  File "/usr/lib64/python3.2/unittest/main.py", line 191, in parseArgs
    self.createTests()
  File "/usr/lib64/python3.2/unittest/main.py", line 198, in createTests
    self.module)
  File "/usr/lib64/python3.2/unittest/loader.py", line 132, in loadTestsFromNames
    suites = [self.loadTestsFromName(name, module) for name in names]
  File "/usr/lib64/python3.2/unittest/loader.py", line 132, in <listcomp>
    suites = [self.loadTestsFromName(name, module) for name in names]
  File "/usr/lib64/python3.2/unittest/loader.py", line 103, in loadTestsFromName
    return self.loadTestsFromModule(obj)
  File "/usr/lib64/python3.2/site-packages/setuptools/command/test.py", line 21, in loadTestsFromModule
    tests.append(module.additional_tests())
  File "/usr/lib64/python3.2/site-packages/zope/interface/tests/__init__.py", line 10, in additional_tests
    locals(), [name])
  File "/usr/lib64/python3.2/site-packages/zope/interface/tests/test_odd_declarations.py", line 34, in <module>
    class Odd(object, metaclass=odd.MetaClass): pass
TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

[Marius Gedminas (mgedmin)]

I cannot reproduce this with zope.interface 4.0.5.

[Marius Gedminas (mgedmin)]

For that matter, I cannot reproduce this with 4.0.1 either. I tried both tox and buildout + bin/test, with Python 3.2.

[Marius Gedminas (mgedmin)]

Some discussion on IRC lead to the discovery that 'python setup.py test' fails when you've got an older version of zope.interface in the system Python site packages.