Nick Coghlan added the comment: Keep in mind that part of the problem here is finding stdlib code that needs to be fixed to handle subclasses correctly. The existing APIs have permitted use with subclasses for years but are, in fact, the wrong tool for that in many cases.
The problem to be solved isn't "this code should handle ducktyping" but, "this code should either reject subclasses or else handle them without corrupting them". Using the same API for both external invocation and for subclasses calling up to the parent is a problem. For code in critical paths, doing the same type check twice is also a problem. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue10977> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com