Fixed #33984 -- Reverted "Fixed #32980 -- Made models cache related managers."

This reverts 4f8c7fd9d91b35e2c2922de4bb50c8c8066cbbc6 and adds
two regression tests:
- test_related_manager_refresh(), and
- test_create_copy_with_m2m().

Thanks joeli for the report.

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/many_to_many/tests.py b/tests/many_to_many/tests.py
index 53e870ddad..729f011446 100644
--- a/tests/many_to_many/tests.py
+++ b/tests/many_to_many/tests.py
@@ -92,6 +92,25 @@ class ManyToManyTests(TestCase):
         a5.authors.remove(user_2.username)
         self.assertSequenceEqual(a5.authors.all(), [])
 
+    def test_related_manager_refresh(self):
+        user_1 = User.objects.create(username="Jean")
+        user_2 = User.objects.create(username="Joe")
+        self.a3.authors.add(user_1.username)
+        self.assertSequenceEqual(user_1.article_set.all(), [self.a3])
+        # Change the username on a different instance of the same user.
+        user_1_from_db = User.objects.get(pk=user_1.pk)
+        self.assertSequenceEqual(user_1_from_db.article_set.all(), [self.a3])
+        user_1_from_db.username = "Paul"
+        self.a3.authors.set([user_2.username])
+        user_1_from_db.save()
+        # Assign a different article.
+        self.a4.authors.add(user_1_from_db.username)
+        self.assertSequenceEqual(user_1_from_db.article_set.all(), [self.a4])
+        # Refresh the instance with an evaluated related manager.
+        user_1.refresh_from_db()
+        self.assertEqual(user_1.username, "Paul")
+        self.assertSequenceEqual(user_1.article_set.all(), [self.a4])
+
     def test_add_remove_invalid_type(self):
         msg = "Field 'id' expected a number but got 'invalid'."
         for method in ["add", "remove"]: