On Sun, 2008-03-23 at 17:42 -0700, George Sakkis wrote: > That's really weird... it's reproducible on Windows too. It doesn't > make any sense why the name of the variable would make a difference. > My guess is you hit some kind of obscure bug.
This is not a bug, just an unexpected feature: http://mail.python.org/pipermail/python-list/2005-January/304873.html What's happening is that at the end of the script, all objects in the global namespace are set to None (in order to decrease their reference count and trigger garbage collection). This happens in the order in which the names appear as keys in the globals dictionary. It randomly happens that "swaroop", "kalam", and "cath" all are hashed in front of "Person", but "cathy" is hashed after "Person". Hence, if Catherine is named cath, Python "None's" all the instances first and then the type last, and all is well. However, if Catherine is called cathy, Person is set to None before cathy. Then, in the lookup of the global name "Person" during cathy.__del__, Person is None, which doesn't have a "population" attribute, causing the AttributeError. Possible workarounds are: 1) Explicitly delete the global names for the instances before the script runs out. 2) Don't refer to the "Person" type by its global name in __del__, but indirectly as type(self). (This requires Person to be a new-style class, though.) -- Carsten Haese http://informixdb.sourceforge.net -- http://mail.python.org/mailman/listinfo/python-list
