Refs #28586 -- Copied fetch modes to related objects.

This change ensures that behavior and performance remain consistent when
traversing relationships.

1 files changed, 31 insertions, 1 deletions

diff --git a/tests/generic_relations/tests.py b/tests/generic_relations/tests.py
index 3de243d7b8..dceb8f4bae 100644
--- a/tests/generic_relations/tests.py
+++ b/tests/generic_relations/tests.py
@@ -813,7 +813,6 @@ class GenericRelationsTests(TestCase):
             self.assertEqual(quartz_tag.content_object, self.quartz)
 
     def test_fetch_mode_raise(self):
-        TaggedItem.objects.create(tag="lion", content_object=self.lion)
         tag = TaggedItem.objects.fetch_mode(RAISE).get(tag="yellow")
         msg = "Fetching of TaggedItem.content_object blocked."
         with self.assertRaisesMessage(FieldFetchBlocked, msg) as cm:
@@ -821,6 +820,37 @@ class GenericRelationsTests(TestCase):
         self.assertIsNone(cm.exception.__cause__)
         self.assertTrue(cm.exception.__suppress_context__)
 
+    def test_fetch_mode_copied_forward_fetching_one(self):
+        tag = TaggedItem.objects.fetch_mode(FETCH_PEERS).get(tag="yellow")
+        self.assertEqual(tag.content_object, self.lion)
+        self.assertEqual(
+            tag.content_object._state.fetch_mode,
+            FETCH_PEERS,
+        )
+
+    def test_fetch_mode_copied_forward_fetching_many(self):
+        tags = list(TaggedItem.objects.fetch_mode(FETCH_PEERS).order_by("tag"))
+        tag = [t for t in tags if t.tag == "yellow"][0]
+        self.assertEqual(tag.content_object, self.lion)
+        self.assertEqual(
+            tag.content_object._state.fetch_mode,
+            FETCH_PEERS,
+        )
+
+    def test_fetch_mode_copied_reverse_fetching_one(self):
+        animal = Animal.objects.fetch_mode(FETCH_PEERS).get(pk=self.lion.pk)
+        self.assertEqual(animal._state.fetch_mode, FETCH_PEERS)
+        tag = animal.tags.get(tag="yellow")
+        self.assertEqual(tag._state.fetch_mode, FETCH_PEERS)
+
+    def test_fetch_mode_copied_reverse_fetching_many(self):
+        animals = list(Animal.objects.fetch_mode(FETCH_PEERS))
+        animal = animals[0]
+        self.assertEqual(animal._state.fetch_mode, FETCH_PEERS)
+        tags = list(animal.tags.all())
+        tag = tags[0]
+        self.assertEqual(tag._state.fetch_mode, FETCH_PEERS)
+
 
 class ProxyRelatedModelTest(TestCase):
     def test_default_behavior(self):