[issue27275] KeyError thrown by optimised collections.OrderedDict.popitem()
New submission from William Pitcock: The C-based optimised version of collections.OrderedDict occasionally throws KeyErrors when deleting items. See https://github.com/mailgun/expiringdict/issues/16 for an example of this regression. Backporting 3.6's patches to 3.5.1 does not resolve the issue. :( -- components: Library (Lib) messages: 267957 nosy: kaniini priority: normal severity: normal status: open title: KeyError thrown by optimised collections.OrderedDict.popitem() type: behavior versions: Python 3.5, Python 3.6 ___ Python tracker <http://bugs.python.org/issue27275> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27275] KeyError thrown by optimised collections.OrderedDict.popitem()
William Pitcock added the comment: A frequent reproducer is to run the expiringdict tests on Python 3.5.1, unfortunately I cannot come up with a testcase. Replacing use of popitem() with "del self[next(OrderedDict.__iter__(self))]" removes the KeyErrors and the structure otherwise works fine. -- ___ Python tracker <http://bugs.python.org/issue27275> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27275] KeyError thrown by optimised collections.OrderedDict.popitem()
William Pitcock added the comment: At least in my case, the application is single-threaded. I don't think this is a locking-related issue as the expiringdict test case itself fails which is also single-threaded. -- ___ Python tracker <http://bugs.python.org/issue27275> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27275] KeyError thrown by optimised collections.OrderedDict.popitem()
William Pitcock added the comment: It seems to me that calling __contains__() (PySequence_Contains()) isn't necessary, as the first and last elements of the list are already known, and therefore known to be in the list. Revising the behaviour of popitem() to avoid calling _odict_popkey_hash() seems like it may provide a marginal performance benefit as well as fix the problem. Calling PyObject_DelItem() directly on the node should work fine I believe. -- ___ Python tracker <http://bugs.python.org/issue27275> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
