Daniel Urban <urban.dani...@gmail.com> added the comment: Thanks for the review!
I've updated my patch: - renamed it to _PyType_CalculateMetaclass - in __build_class__ call it even when a metaclass is declared - added a test for this case (which fails with my previous patch) However I noticed another problem: the declared metaclass (the object passed with the metaclass keyword in the class definition) according to PEP 3115 can be any callable object, not only a PyTypeObject. Problems: 1. In this case, PyType_IsSubtype will be called on something that is not a PyTypeObject (I don't know if that's a big problem, currently it seems to work). 2. The bigger problem: a simple construct, like: class X(object, metaclass=func): pass (where func is for example a function) won't work, because in _PyType_CalculateMetaclass it will detect, that func isn't a super- or subtype of object.__class__, and will raise an exception: "metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases". My first idea to solve this problem is to ignore this case in __build_class__ (check for a returned NULL, and call PyErr_Clear), and use the declared metaclass. (I don't know, if this can cause other problems, I haven't thought much about it yet.) ---------- Added file: http://bugs.python.org/file21729/issue_1294232_2.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue1294232> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com