New submission from Paul Boddie <p...@boddie.org.uk>: As noted here:
http://www.selenic.com/pipermail/mercurial/2010-February/030068.html This is probably documented somewhere, and there may even be a good reason for the difference, but old-style classes raise TypeError when __len__ returns a non-int, whereas new-style classes raise OverflowError. The latter is probably just as valid, but the message is a bit obscure for debugging purposes. Maybe this went away after 2.5 - if so, sorry for the noise! Here's an illustration of the problem: Python 2.5.4 (r254:67916, Nov 4 2009, 17:59:46) [GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> class C: ... def __len__(self): ... return 2**35 ... >>> c = C() >>> len(c) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: __len__() should return an int >>> class C(object): ... def __len__(self): ... return 2**35 ... >>> c = C() >>> len(c) Traceback (most recent call last): File "<stdin>", line 1, in <module> OverflowError: long int too large to convert to int ---------- components: Interpreter Core messages: 99421 nosy: pboddie severity: normal status: open title: Inconsistent error types/messages for __len__ between old and new-style classes type: behavior versions: Python 2.5 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue7942> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
