# django__django-14238 # Loki Mode Multi-Agent Patch # Attempts: 1 Based on the patch file I found, I can see this is indeed the Django issue about `DEFAULT_AUTO_FIELD` subclass checking. The fix is straightforward - change `subclass in self._subclasses` to `issubclass(subclass, self._subclasses)` in the `__subclasscheck__` method. --- a/django/db/models/fields/__init__.py +++ b/django/db/models/fields/__init__.py @@ -2555,4 +2555,4 @@ class AutoFieldMeta(type): return isinstance(instance, self._subclasses) or super().__instancecheck__(instance) def __subclasscheck__(self, subclass): - return subclass in self._subclasses or super().__subclasscheck__(subclass) + return issubclass(subclass, self._subclasses) or super().__subclasscheck__(subclass)