Raymond Hettinger <raymond.hettin...@gmail.com> added the comment:
> As in most (but not all) cases of dunder methods it > is looked up in a class, ignoring instance attributes. That is true, but the starting point in this case is a class so the attribute lookup should be in that class, not its metaclass. Guido's original code was correct and it became broken in 3.1 in the switch from PyObject_GetAttr(cls, name) to _PyObject_LookupSpecial(cls, &PyId___instancecheck__). Also, the demonstration code I gave (that matches the documentation) used to work in 3.0 and prior. It broken in 3.1. ---------- nosy: +gvanrossum _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue45791> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
