id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
20442	Stale ContentType objects cause a NoneType error in get_for_id	Diederik van der Boor	Diederik van der Boor	"When content types are stale an error occurs when using `ContentType.objects.get_for_id()`:

{{{
Traceback (most recent call last):
  ...
  File ""/Users/diederik/Sites/webapps/django/django/contrib/contenttypes/tests.py"", line 280, in <lambda>
    test = ContentType.objects.get_for_id(ct.pk)
  File ""/Users/diederik/Sites/webapps/django/django/contrib/contenttypes/models.py"", line 107, in get_for_id
    self._add_to_cache(self.db, ct)
  File ""/Users/diederik/Sites/webapps/django/django/contrib/contenttypes/models.py"", line 122, in _add_to_cache
    key = (model._meta.app_label, model._meta.model_name)
AttributeError: 'NoneType' object has no attribute '_meta'
}}}

The object can still be fetched, but `ct.model_class()` returns `None` which causes the `_add_to_cache` function to operate on a NoneType.
"	Bug	closed	contrib.contenttypes	1.6	Normal	fixed	dceu13		Unreviewed	1	0	0	0	0	0