From 198b30168d4e94af42e0dc7967bd3259b5c5790b Mon Sep 17 00:00:00 2001 From: Simon Charette Date: Sat, 25 Jan 2025 00:12:17 -0500 Subject: Fixed #36135 -- Fixed reverse GenericRelation prefetching. The get_(local|foreign)_related_value methods of GenericRelation must be reversed because it defines (from|to)_fields and associated related_fields in the reversed order as it's effectively a reverse GenericForeignKey itself. The related value methods must also account for the fact that referenced primary key values might be stored as a string on the model defining the GenericForeignKey but as integer on the model defining the GenericRelation. This is achieved by calling the to_python method of the involved content type in get_foreign_related_value just like GenericRelatedObjectManager does. Lastly reverse many-to-one manager's prefetch_related_querysets should use set_cached_value instead of direct attribute assignment as direct assignment might are disallowed on ReverseManyToOneDescriptor descriptors. This is likely something that was missed in f5233dc (refs #32511) when the is_cached guard was added. Thanks 1xinghuan for the report. --- tests/prefetch_related/tests.py | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'tests') diff --git a/tests/prefetch_related/tests.py b/tests/prefetch_related/tests.py index b44a34c456..d3c096574a 100644 --- a/tests/prefetch_related/tests.py +++ b/tests/prefetch_related/tests.py @@ -1254,6 +1254,20 @@ class GenericRelationTests(TestCase): ], ) + def test_reverse_generic_relation(self): + # Create two distinct bookmarks to ensure the bookmark and + # tagged item models primary are offset. + first_bookmark = Bookmark.objects.create() + second_bookmark = Bookmark.objects.create() + TaggedItem.objects.create( + content_object=first_bookmark, favorite=second_bookmark + ) + with self.assertNumQueries(2): + obj = TaggedItem.objects.prefetch_related("favorite_bookmarks").get() + with self.assertNumQueries(0): + prefetched_bookmarks = obj.favorite_bookmarks.all() + self.assertQuerySetEqual(prefetched_bookmarks, [second_bookmark]) + class MultiTableInheritanceTest(TestCase): @classmethod -- cgit v1.3