[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Irit Katriel added the comment: PR27648 fixes this, but it also breaks test_abc.test_issubclass_bad_arguments so it's not quite right. I don't know this area, but I think the problem is in the place the PR changes, and that the issue is due to this difference in the type of __subclasses__

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Change by Irit Katriel : -- keywords: +patch nosy: +iritkatriel nosy_count: 7.0 -> 8.0 pull_requests: +26142 stage: -> patch review pull_request: https://github.com/python/cpython/pull/27648 ___ Python tracker

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Change by myungsekyo : -- nosy: +myungsekyo ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Change by Caleb Donovick : -- nosy: +donovick ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Change by Jeffrey Kintscher : -- nosy: +Jeffrey.Kintscher ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Ivan Levkivskyi added the comment: I think this is related to how `__subclasscheck__` is implemented in `ABCMeta`. I just checked this also happens in Python 3.6 (i.e. it is not something specific to the C version introduced in Python 3.7). --

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Change by Ivan Levkivskyi : -- nosy: +levkivskyi ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

Change by SilentGhost : -- nosy: +rhettinger, stutzbach type: -> behavior ___ Python tracker ___ ___ Python-bugs-list mailing list

[issue36881] isinstance raises TypeError for metaclass with metaclass=ABCMeta

New submission from Randy Eckman : >>> from abc import ABCMeta >>> class AbstractMeta(type, metaclass=ABCMeta): pass ... >>> class Meta1(AbstractMeta): pass ... >>> class Meta2(AbstractMeta): pass ... >>> class ClassA(metaclass=Meta1): pass ... >>> isinstance(ClassA, Meta2) Traceback (most