Commit 5e2c4d7a authored by Attila Tovt's avatar Attila Tovt Committed by Tim Graham
Browse files

Fixed #26264 -- Fixed prefetch_related() crashes with values_list(flat=True)

parent 3389c5ea

django/db/models/query.py

+6 −5
Original line number Diff line number Diff line
@@ -1421,11 +1421,12 @@ def prefetch_related_objects(model_instances, *related_lookups): 
                if not hasattr(obj, '_prefetched_objects_cache'):

                    try:

                        obj._prefetched_objects_cache = {}

                    except AttributeError:

                        # Must be in a QuerySet subclass that is not returning

                        # Model instances, either in Django or 3rd

                        # party. prefetch_related() doesn't make sense, so quit

                        # now.

                    except (AttributeError, TypeError):

                        # Must be an immutable object from

                        # values_list(flat=True), for example (TypeError) or

                        # a QuerySet subclass that isn't returning Model

                        # instances (AttributeError), either in Django or a 3rd

                        # party. prefetch_related() doesn't make sense, so quit.

                        good_objects = False

                        break

            if not good_objects:

tests/prefetch_related/test_uuid.py

+11 −0
Original line number Diff line number Diff line
@@ -44,6 +44,17 @@ class UUIDPrefetchRelated(TestCase): 
        with self.assertNumQueries(0):

            self.assertEqual(2, len(flea.pets_visited.all()))



    def test_prefetch_related_from_uuid_model_to_uuid_model_with_values_flat(self):

        pet = Pet.objects.create(name='Fifi')

        pet.people.add(

            Person.objects.create(name='Ellen'),

            Person.objects.create(name='George'),

        )

        self.assertSequenceEqual(

            Pet.objects.prefetch_related('fleas_hosted').values_list('id', flat=True),

            [pet.id]

        )





class UUIDPrefetchRelatedLookups(TestCase):