Fixes #20587: Handle stale ContentTypes in has_feature() #20592
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
When deleting stale ContentTypes during remove_stale_contenttypes, the pre_delete signal triggers notify_object_changed(), which calls has_feature() with the ContentType instance. For stale types (those with no corresponding model class), model_class() returns None, which then gets passed to issubclass() in the feature test lambda, causing a TypeError. The previous implementation in has_feature() checked for None before attempting ObjectType lookup. The optimization in 5ceb6a6 removed this safety check when refactoring the ContentType code path to use direct feature registry lookups. This restores the null check to maintain the original behavior of returning False for stale ContentTypes.
jnovinger
requested review from
a team and
jeremystretch
and removed request for
a team
jeremystretch
approved these changes
Oct 15, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fixes: #20587
Fixes #20587 (and its duplicate #20588) by adding a null check when handling stale
ContentTypes inhas_feature().When running
remove_stale_contenttypes(executed byupgrade.sh), the management command fails withTypeError: issubclass() arg 1 must be a class. This occurs when deleting ContentTypes that no longer have corresponding model classes—referred to as "stale" ContentTypes. These arise when models are renamed/removed between versions or when plugins are uninstalled.The error path:
pre_deletesignal fires when deleting the stale ContentTypenotify_object_changed()signal handler callshas_feature(instance, 'notifications')has_feature()callsmodel_class()on the ContentType, which returnsNonefor stale typesNonegets passed directly to the feature test lambda:issubclass(None, NotificationsMixin)→ TypeErrorRoot Cause:
Commit 5ceb6a6 (which fixed #20290) changed the ContentType code path in
has_feature()to use direct feature registry lookups in addition to ObjectType lookups. However, this refactoring inadvertently removed the null safety check that existed in the previous implementation.https://gist.github.com/jnovinger/35948fc653c0425a5f9b207f9b77883f is available as a reproduction script to verify this fix.