Refs #28723 -- Fixed stale prefetch_related cache after add/remove.

Regression in 514b2c989a948e3c59bda0da0c9427acf643cf5b.

2 files changed, 17 insertions, 1 deletions

diff --git a/tests/prefetch_related/models.py b/tests/prefetch_related/models.py
index 68fdc2686d..cb64b52a15 100644
--- a/tests/prefetch_related/models.py
+++ b/tests/prefetch_related/models.py
@@ -86,7 +86,8 @@ class Reader(models.Model):
 
 
 class BookReview(models.Model):
-    book = models.ForeignKey(BookWithYear, models.CASCADE)
+    # Intentionally does not have a related name.
+    book = models.ForeignKey(BookWithYear, models.CASCADE, null=True)
     notes = models.TextField(null=True, blank=True)
 
 
diff --git a/tests/prefetch_related/tests.py b/tests/prefetch_related/tests.py
index adadfa33b2..e92d7f349f 100644
--- a/tests/prefetch_related/tests.py
+++ b/tests/prefetch_related/tests.py
@@ -1415,6 +1415,21 @@ class DirectPrefechedObjectCacheReuseTests(TestCase):
         with self.assertNumQueries(0):
             prefetch_related_objects([bookwithyear1], 'bookreview_set')
 
+    def test_add_clears_prefetched_objects(self):
+        bookwithyear = BookWithYear.objects.get(pk=self.bookwithyear1.pk)
+        prefetch_related_objects([bookwithyear], 'bookreview_set')
+        self.assertCountEqual(bookwithyear.bookreview_set.all(), [self.bookreview1])
+        new_review = BookReview.objects.create()
+        bookwithyear.bookreview_set.add(new_review)
+        self.assertCountEqual(bookwithyear.bookreview_set.all(), [self.bookreview1, new_review])
+
+    def test_remove_clears_prefetched_objects(self):
+        bookwithyear = BookWithYear.objects.get(pk=self.bookwithyear1.pk)
+        prefetch_related_objects([bookwithyear], 'bookreview_set')
+        self.assertCountEqual(bookwithyear.bookreview_set.all(), [self.bookreview1])
+        bookwithyear.bookreview_set.remove(self.bookreview1)
+        self.assertCountEqual(bookwithyear.bookreview_set.all(), [])
+
 
 class ReadPrefetchedObjectsCacheTests(TestCase):
     @classmethod