Yuri, I think you are making a good case (though I would like for you to be a good citizen and use the bug tracker to submit this for review). Benjamin, what do you think?
--Guido On Mon, Aug 23, 2010 at 7:14 PM, Yury Selivanov <yseliva...@gmail.com> wrote: >> On 2010-08-23, at 10:56 AM, Guido van Rossum wrote: >> On Mon, Aug 23, 2010 at 7:46 AM, Benjamin Peterson <benja...@python.org> >> wrote: >>> 2010/8/23 Yury Selivanov <yseliva...@gmail.com>: >>>> 1) I propose to change 'hasattr' behaviour in Python 3, making it to >>>> swallow only AttributeError exceptions (exactly like 'getattr'). >>>> Probably, Python 3.2 release is our last chance. >>> >>> I would be in support of that. >> >> I am cautiously in favor. The existing behavior is definitely a >> mistake and a trap. But it has been depended on for almost 20 years >> now. >> >> I recommend that you create a patch, apply it, run the *entire* stdlib >> test suite and see how much breaks. That will give you an idea of the >> damage to expect for 3rd party code. > > Have done a little testing. > > The patch to builtin 'hasattr' function is trivial, and can be found > attached to this letter (with the corresponding unittest): > > - if (!PyErr_ExceptionMatches(PyExc_Exception)) > + if (!PyErr_ExceptionMatches(PyExc_AttributeError)) > > So, after applying it, hasattr swallows only AttributeError exceptions. > > > All tests from Python 3.2 test suite were good. > > After that, I've applied the patch on Python 2.6 and tested SqlAlchemy, > Django and Twisted. > > - SqlAlchemy has failed three unittests, but those tests were designed > specifically to handle 'hasattr' weird behaviour, so we can consider > the change has no impact on SqlAlchemy. > > - Twisted - failed 3 tests out of ~3200, but it fails them on the same > machine on an unpatched Python too, and they seem unrelated. > > - Django - all tests passed. > > > I tested our internal company framework (~100K LOC) and, again, all > tests passed. > > > -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
