[issue12248] __dir__ semantics changed in Python 2.7.2
Soren Hansen added the comment: When I first investigated this problem (I reported the original bug on Launchpad), my first attempt to address this issue in pymox had me quite stumped. The class in question has a __getattr__ method. Up until now, this hasn't affected the use of dir(), but it does now. I really just wanted it return whatever it used to return (since that has worked so far), but realising that this was an old-style class, I couldn't just call super(TheClass, self).__dir__(). So my question is: If this change stays (which seems clear given that the only changes proposed here are ways of relaxing the type requirement of the __dir__ method's return value, not reverting the change altogether), and I have an old-style class with a __getattr__ defined, how do I make that class return whatever it would have usually returned for __dir__()? -- nosy: +soren ___ Python tracker <http://bugs.python.org/issue12248> ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12248] __dir__ semantics changed in Python 2.7.2
Soren Hansen added the comment: 2011/6/4 Benjamin Peterson : > 2011/6/4 Soren Hansen : >> So my question is: If this change stays (which seems clear given that the >> only changes proposed here are ways of relaxing the type requirement of the >> __dir__ method's return value, not reverting the change altogether), and I >> have an old-style class with a __getattr__ defined, how do I make that class >> return whatever it would have usually returned for __dir__()? > > Yes, this is a limitation of magic methods on old style classes. The > usual method is something like this: > > def __getattr__(self, name): > if name == "__dir__": > return self.__dir__ > # Other stuff > > Of course, the best fix is to use new-style classes. :) If I do this: = test.py == class Foo: def __getattr__(self, name): if name == '__dir__': return self.__dir__ return 'something else' a = Foo() print dir(a) After a lot of this: File "test.py", line 4, in __getattr__ return self.__dir__ File "test.py", line 4, in __getattr__ return self.__dir__ File "test.py", line 4, in __getattr__ return self.__dir__ ...I end up with a "RuntimeError: maximum recursion depth exceeded". I can't say I'm surprised :) -- ___ Python tracker <http://bugs.python.org/issue12248> ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12248] __dir__ semantics changed in Python 2.7.2
Soren Hansen added the comment: 2011/6/5 Benjamin Peterson : > 2011/6/4 Soren Hansen : >> ...I end up with a "RuntimeError: maximum recursion depth exceeded". I >> can't say I'm surprised :) > Ah, sorry I should have thought before writing that. :) > self.__class__.__dir__.__get__(self, self.__class__) should work, > though. Yeah, that one does seem to work. Excellent, thanks! -- ___ Python tracker <http://bugs.python.org/issue12248> ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
