Title: isinstance() and issubclass() fail with abc.ABCMeta
Type: Severity: normal
Components: Core Versions: Jython 2.7
Milestone: Jython 2.7.2
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: Nosy List: Arfrever, gthank, jeff.allen, pjenvey, zyasoft
Priority: Keywords:

Created on 2013-05-20.09:52:20 by Arfrever, last changed 2018-03-23.22:36:14 by jeff.allen.

msg8023 (view) Author: Arfrever Frehtes Taifersar Arahesis (Arfrever) Date: 2013-05-20.09:52:20
isinstance() and issubclass() fail with abc.ABCMeta in Jython. They work in CPython.

$ cat
import abc
class A(abc.ABCMeta): pass
print(isinstance(0, abc.ABCMeta))
print(issubclass(A, abc.ABCMeta))
print(issubclass(abc.ABCMeta, abc.ABCMeta))
$ python2.7
$ jython2.7
Traceback (most recent call last):
  File "", line 3, in <module>
    print(isinstance(0, abc.ABCMeta))
RuntimeError: maximum recursion depth exceeded in __instancecheck__
msg8024 (view) Author: Philip Jenvey (pjenvey) Date: 2013-05-20.18:08:27
It'd be helpful to know what method call inside of __instancecheck__ (I assume the message refers to ABCMeta.__instance__check__) ends up triggering the recursion
msg8397 (view) Author: Hank Gay (gthank) Date: 2014-05-13.19:49:42
Target beta 4.
msg8398 (view) Author: Jim Baker (zyasoft) Date: 2014-05-13.20:08:48
Interesting, I was reviewing and I see that there was a related problem in CPython earlier, as seen in the commented-out code. Of course this commented-out code actually works on both CPython and Jython now, so we have to fix Arfrever's case:

    def test_isinstance_class(self):
        class A:
            __metaclass__ = abc.ABCMeta
        class OldstyleClass:
        self.assertFalse(isinstance(OldstyleClass, A))
        self.assertTrue(isinstance(OldstyleClass, type(OldstyleClass)))
        self.assertFalse(isinstance(A, OldstyleClass))
        # This raises a recursion depth error, but is low-priority:
        # self.assertTrue(isinstance(A, abc.ABCMeta))
msg11706 (view) Author: Jeff Allen (jeff.allen) Date: 2018-02-24.23:33:24
This seems to be working now:
PS 272a1> jython
Jython 2.7.2a1+ (default:d74f8c2cd56f, Feb 24 2018, 17:18:53)
[Java HotSpot(TM) 64-Bit Server VM (Oracle Corporation)] on java1.8.0_151
Type "help", "copyright", "credits" or "license" for more information.
>>> import abc
>>> class A(abc.ABCMeta): pass
>>> print(isinstance(0, abc.ABCMeta))
>>> print(issubclass(A, abc.ABCMeta))
>>> print(issubclass(abc.ABCMeta, abc.ABCMeta))

msg11853 (view) Author: Jeff Allen (jeff.allen) Date: 2018-03-23.22:36:14
Now apparently fixed, but I don't know at what changeset. Given #msg8398 it was fixed by updates to the stdlib?
Date User Action Args
2018-03-23 22:36:14jeff.allensetstatus: open -> closed
resolution: accepted -> fixed
messages: + msg11853
2018-02-24 23:33:24jeff.allensetnosy: + jeff.allen
messages: + msg11706
2015-11-02 03:21:29zyasoftsetmilestone: Jython 2.7.2
2014-05-13 20:08:48zyasoftsetnosy: + zyasoft
messages: + msg8398
2014-05-13 19:49:42gthanksetnosy: + gthank
messages: + msg8397
2014-05-04 20:29:36zyasoftsetresolution: accepted
2013-05-20 18:08:27pjenveysetmessages: + msg8024
2013-05-20 09:53:56Arfreversetnosy: + pjenvey
2013-05-20 09:52:20Arfrevercreate