Error in admin.site.register on pypy3.8 and Django 4.1+.

[Hasan Ramezani]

I tried to ​include Django 4.1 in django-axes. then I noticed the CI fails on ​Django 4.1 and ​Django main with the following error:

   File "/home/runner/work/django-axes/django-axes/.tox/pypy38-djmain/lib/pypy3.8/site-packages/django/contrib/auth/admin.py", line 29, in <module>
      class GroupAdmin(admin.ModelAdmin):
    File "/home/runner/work/django-axes/django-axes/.tox/pypy38-djmain/lib/pypy3.8/site-packages/django/contrib/admin/decorators.py", line 102, in _model_admin_wrapper
      raise ValueError("site must subclass AdminSite")
  ValueError: site must subclass AdminSite

It seems the error comes from ​register decorator

I've checked it and found this introduced after ​https://github.com/django/django/commit/97d7990abde3fe4b525ae83958fd0b52d6a1d13f

It seems the if not isinstance(admin_site, AdminSite): returns False after this change.

[Mariusz Felisiak]

Thanks for this ticket, however this can be an issue in PyPy, not in Django itself. Can you debug this issue and provide details about why and where Django is at fault? I'd start from creating a bug report in PyPy and reopen this ticket if they indicate that Django is at fault.

[Hasan Ramezani]

Ah sorry for the duplication.
Seems there is a related issue in ​PyPy and also you discussed about it in https://code.djangoproject.com/ticket/28358#comment:13

[Mariusz Felisiak]

I missed my own comments 🤦