Jim Jewett added the comment: If I know that a Counter (or any class X) can be updated in place, I will be surprised to find out that I'm using a different instance after a successful in-place operation.
I would even consider that (replacement of the original instance) a security risk, though it is mitigated by the fact that I don't see how to exploit it without already being able to create arbitrary subclasses. > For subclassing to work, the fix is: > > if not hasattr(other, 'items') or type(self) is not Counter: > return NotImplemented That breaks for Counter subclasses on the left hand side -- even a trivial subclass to change the repr would fail unless the _i* methods were all re-implemented, either by the otherwise-trivial Counter subclass or by the right-hand objects. If you start making it work for the obvious cases, you just make the failure conditions more obscure. ---------- nosy: +Jim.Jewett _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue22766> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
