2010/10/27 Tres Seaver <tseaver@palladion.com>:
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On 10/27/2010 07:58 AM, Zope Tests Summarizer wrote: ...
Subject: FAILED : Zope Buildbot / zopetoolkit-py2.7 slave-ubuntu64 From: jdriessen at thehealthagency.com Date: Wed Oct 27 04:49:22 EDT 2010 URL: http://mail.zope.org/pipermail/zope-tests/2010-October/022426.html
Subject: FAILED : Zope Buildbot / zopetoolkit-py2.7 slave-ubuntu32 From: jdriessen at thehealthagency.com Date: Wed Oct 27 04:49:43 EDT 2010 URL: http://mail.zope.org/pipermail/zope-tests/2010-October/022427.html
Our failures now seem to be all on Python 2.7 (progress, of a sort). Many of them fail due to the following attempt to use a proxy as the target of a weakref:
- ----------------------------- %< ----------------------------- File "/home/zope/.buildout/eggs/zope.security-3.7.4-py2.7-linux-i686.egg/zope/security/tests/test_standard_checkers.py", line 509, in zope.security.tests.test_standard_checkers.test_ABCMeta Failed example: issubclass(PBar, Foo) Exception raised: Traceback (most recent call last): File "/usr/lib/python2.7/doctest.py", line 1253, in __run compileflags, 1) in test.globs File "<doctest zope.security.tests.test_standard_checkers.test_ABCMeta[6]>", line 1, in <module> issubclass(PBar, Foo) File "/usr/lib/python2.7/abc.py", line 151, in __subclasscheck__ if subclass in cls._abc_cache: File "/usr/lib/python2.7/_weakrefset.py", line 69, in __contains__ return ref(item) in self.data TypeError: cannot create weak reference to 'zope.security._proxy._Proxy' object
Ran 124 tests with 1 failures and 0 errors in 0.433 seconds. Tearing down left over layers: Tear down zope.testrunner.layer.UnitTests in 0.000 seconds. - ----------------------------- %< -----------------------------
Observations:
- - Proxies can't be weakref targets under either Python 2.6 or 2.7.
- - Under Python 2.7, the ABCMeta._abc_cache involved in the traceback is being morphed from a normal set (per the __new__ of the metaclass) to a _weakrefset.WeakSet. Such sets cannot hold non-weakref-target objects.
I investigated this issue today, and committed a fix http://zope3.pov.lt/trac/changeset/121714 It removes a check issubclass(PBar, Foo), where PBar is a proxy of class Bar. This worked in Python 2.6, but not in Python 2.7 anymore because ABC implementation was changed to use a WeakSet instead of set for the cache, and _Proxy objects cannot be ref'ed. However, other objects cannot be ref'ed either, the first argument to issubclass has to be a type (see http://bugs.python.org/issue10569). http://docs.zope.org/zopetoolkit/releases/overview-1.1.html#python-versions links to http://bugs.python.org/issue10360 as the underlying problem. I have applied the patch, but the test fails in the same place with a different stacktrace: File "/home/menesis/.buildout/eggs/zope.security-3.8.1-py2.7-linux-i686.egg/zope/security/tests/test_standard_checkers.py", line 509, in zope.security.tests.test_standard_checkers.test_ABCMeta Failed example: issubclass(PBar, Foo) Exception raised: Traceback (most recent call last): File "/usr/lib/python2.7/doctest.py", line 1254, in __run compileflags, 1) in test.globs File "<doctest zope.security.tests.test_standard_checkers.test_ABCMeta[6]>", line 1, in <module> issubclass(PBar, Foo) File "/home/menesis/src/zope/zopetoolkit-1.1/python/lib/python2.7/abc.py", line 171, in __subclasscheck__ cls._abc_cache.add(subclass) File "/home/menesis/src/zope/zopetoolkit-1.1/python/lib/python2.7/_weakrefset.py", line 84, in add self.data.add(ref(item, self._remove)) TypeError: cannot create weak reference to 'zope.security._proxy._Proxy' object So the patch, that we were waiting for to be released with python 2.7.2, does not help. So I removed the (incorrect) issubclass call, and the rest of the test passes, showing that ABC checker works correctly. Even if it would be good that issubclass worked, I think that mixing ABCs and Zope interfaces is very unlikely anyway. But having one test that is known to fail, and consequently not test all of ZTK at all is wrong. Now ZTK builders on python 2.7 can be added/enabled again. Please do so. Gediminas