Fixed #28723 -- Fixed RelatedManager's prefetch_related() cache name.

django/db/models/fields/related_descriptors.py

@@ -581,7 +581,7 @@ def create_reverse_many_to_one_manager(superclass, rel):
 
         def get_queryset(self):
             try:
-                return self.instance._prefetched_objects_cache[self.field.related_query_name()]
+                return self.instance._prefetched_objects_cache[self.field.remote_field.get_cache_name()]
             except (AttributeError, KeyError):
                 queryset = super().get_queryset()
                 return self._apply_rel_filters(queryset)
@@ -604,7 +604,7 @@ def create_reverse_many_to_one_manager(superclass, rel):
             for rel_obj in queryset:
                 instance = instances_dict[rel_obj_attr(rel_obj)]
                 setattr(rel_obj, self.field.name, instance)
-            cache_name = self.field.related_query_name()
+            cache_name = self.field.remote_field.get_cache_name()
             return queryset, rel_obj_attr, instance_attr, False, cache_name, False
 
         def add(self, *objs, bulk=True):

tests/prefetch_related/tests.py

@@ -2,7 +2,7 @@ from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ObjectDoesNotExist
 from django.db import connection
 from django.db.models import Prefetch, QuerySet
-from django.db.models.query import get_prefetcher
+from django.db.models.query import get_prefetcher, prefetch_related_objects
 from django.test import TestCase, override_settings
 from django.test.utils import CaptureQueriesContext
 
@@ -1329,6 +1329,8 @@ class DirectPrefechedObjectCacheReuseTests(TestCase):
             AuthorAddress.objects.create(author=cls.author12, address='Haunted house'),
             AuthorAddress.objects.create(author=cls.author21, address='Happy place'),
         ]
+        cls.bookwithyear1 = BookWithYear.objects.create(title='Poems', published_year=2010)
+        cls.bookreview1 = BookReview.objects.create(book=cls.bookwithyear1)
 
     def test_detect_is_fetched(self):
         """
@@ -1405,6 +1407,14 @@ class DirectPrefechedObjectCacheReuseTests(TestCase):
             self.assertEqual(book1.first_authors[1].happy_place, [])
             self.assertEqual(book2.first_authors[0].happy_place, [self.author2_address1])
 
+    def test_prefetch_reverse_foreign_key(self):
+        with self.assertNumQueries(2):
+            bookwithyear1, = BookWithYear.objects.prefetch_related('bookreview_set')
+        with self.assertNumQueries(0):
+            self.assertCountEqual(bookwithyear1.bookreview_set.all(), [self.bookreview1])
+        with self.assertNumQueries(0):
+            prefetch_related_objects([bookwithyear1], 'bookreview_set')
+
 
 class ReadPrefetchedObjectsCacheTests(TestCase):
     @classmethod