[Zope-dev] SVN: zope.interface/trunk/ Fix a regression introduced in 3.6.4, that made one zope.app.interface test fail

[Gediminas Paulauskas]

2011/8/6 Tres Seaver <tseaver at palladion.com>:
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> On 08/04/2011 10:18 AM, Gediminas Paulauskas wrote:
>> Log message for revision 122462: Fix a regression introduced in
>> 3.6.4, that made one zope.app.interface test fail
>>
>>
>> Changed: U   zope.interface/trunk/CHANGES.txt U
>> zope.interface/trunk/src/zope/interface/interface.py
>>
>> -=- Modified: zope.interface/trunk/CHANGES.txt
>> ===================================================================
>> --- zope.interface/trunk/CHANGES.txt  2011-08-04 13:44:20 UTC (rev
>> 122461) +++ zope.interface/trunk/CHANGES.txt  2011-08-04 14:18:37 UTC
>> (rev 122462) @@ -11,10 +11,12 @@
>>
>> - Fix testing deprecation warnings issued when tested under Py3K.
>>
>> +- Fix ``InterfaceClass.__hash__`` to match comparison function. +
>> 3.6.4 (2011-07-04) ------------------
>>
>> -- LP 804951:  InterfaceClass instances were unhashable under Python
>> 3.x. +- LP #804951:  InterfaceClass instances were unhashable under
>> Python 3.x.
>>
>> 3.6.3 (2011-05-26) ------------------
>>
>> Modified: zope.interface/trunk/src/zope/interface/interface.py
>> ===================================================================
>> --- zope.interface/trunk/src/zope/interface/interface.py      2011-08-04
>> 13:44:20 UTC (rev 122461) +++
>> zope.interface/trunk/src/zope/interface/interface.py  2011-08-04
>> 14:18:37 UTC (rev 122462) @@ -682,7 +682,8 @@ return (n1 > n2) - (n1
>> < n2)
>>
>> def __hash__(self): -        return hash((self.__name__,
>> self.__module__)) +        return hash((getattr(self, '__name__',
>> ''), +                     getattr(self, '__module__', '')))
>
> I don't think this is a regression -- how do you legitimately create an
> interface without both those attributes?   The point of the comparison
> function is to work even when handed a non-Interface object as one of
> the two terms being compared, which doesn't apply to the case of a hash.
> If there is code in zope.app.interface which is constructing a class
> derived from Interface but which doesn't call Interface.__init__ before
> hashing the instance, that code is *broken*, and should be fixed.

It was my attempt to fix tests that were failing for more than a week,
and it worked. zope.app.interface might be broken, but I couldn't
understand why
it failed, especially the "foreign connection" exception. Here I saw
asymmetry between __eq__ and __hash__, and I still feel that my fix
was better than returning 1.

In addition to zope.app.interface, there was another problem with
Tahoe-LAFS: https://bugs.launchpad.net/zope.interface/+bug/811792 that
Tres helped to solve.

-- 
Gediminas