[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Nikolaus Rath added the comment: Raymond, it would be nice if you could respond to my last comment... -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Raymond Hettinger added the comment: Sorry Nikolaus, I'm happy with the code and docs as they are. In general, you should assume that unless documented otherwise, any pure python container (stdlib or 3rd party) has undefined behavior if you mutate while iterating (like you should not assume thread-safety unless a container is documented as threadsafe). At your behest, I added extra code to trigger an earlier and more visible failure in some circumstances, but that is the limit. OrderedDicts have been around for a good while (not just the stdlib but also in other code predating the one in the stdlib), so we know that this hasn't been a problem in practice. Please declare victory, move on, and don't keep extending this closed thread. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Nikolaus Rath added the comment: Raymond, I think your patch does not really address the issue reported here. The dict documentation still guarantees that mutating a dict during iteration will raise a RuntimeError or may skip elements. The OrderedDict documentation still does not point out that OrderedDicts behave differently, yet they still raise a different exception than a regular dict in the same situation. I believe it should be possible to pass an OrderedDict to any function expecting a regular dict. This is still not possible. But even if you think this is not desirable (or not worth the cost), could we at least *document* that OrderedDicts behave differently? -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Roundup Robot added the comment: New changeset a3c345ba3563 by Raymond Hettinger in branch 'default': Issue #19414: Have the OrderedDict mark deleted links as unusable. http://hg.python.org/cpython/rev/a3c345ba3563 -- nosy: +python-dev ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Raymond Hettinger added the comment: To address Armin's concern, I'm triggering an early failure by setting the link fields to None. That will help prevent accidental reliance on non-guaranteed behaviors. -- resolution: - fixed status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Nikolaus Rath added the comment: The patch applies cleanly to 3.4 and 3.5, not sure why the review link does not show up. I'm attaching the file again, maybe that helps. -- Added file: http://bugs.python.org/file34804/issue19414_r2.diff ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Chris Angelico added the comment: I agree that current behaviour is a bit confusing; also, the implication is that deleting from the dictionary while you have an iterator may leave some hanging references around the place, which raises a red flag in my mind (maybe something else might find the stale data, too). My inclination would be to Armin's idea of setting next to None. Seems simpler than trying too hard to patch around something that's a bad idea anyway. -- nosy: +Rosuav ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Changes by Alexander Belopolsky alexander.belopol...@gmail.com: -- nosy: +belopolsky ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Nikolaus Rath added the comment: I have attached a patch that fixes this issue. Looking at Raymonds comments in issue 19332, I have kept new code out of the critical path in __iter__ and instead modified the __delitem__ method (I assume that an element is removed only once, but may be iterated over many times). The updated __delitem__ now also updates the prev and next links of the removed item itself. When the current item is removed during an iteration, the iteration thus stops. I hope that's an acceptable solution. -- keywords: +patch Added file: http://bugs.python.org/file33359/issue19414.diff ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue19414] iter(ordered_dict) yields keys not in dict in some circumstances
Changes by Nikolaus Rath nikol...@rath.org: -- title: OrderedDict.values() behavior for modified instance - iter(ordered_dict) yields keys not in dict in some circumstances ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue19414 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
