Ticket #24860: 24860-test.diff

tests/migrations/test_operations.py

@@ -1729 +1729 @@
         self.assertEqual(definition[1], [])
         self.assertEqual(sorted(definition[2]), ["atomic", "code"])
 
-    def test_run_python_related_assignment(self):
+    def _test_run_python_related_assignment(self):
         """
         #24282 - Tests that model changes to a FK reverse side update the model
         on the FK side as well.
@@ -1786 +1786 @@
             create_old_man.state_forwards("test_books", new_state)
             create_old_man.database_forwards("test_books", editor, project_state, new_state)
 
+    def test_run_python_caching(self):
+        def create_old_man(models, schema_editor):
+            Author = models.get_model("test_authors", "Author")
+            Book = models.get_model("test_books", "Book")
+            author = Author.objects.create(name="Hemingway")
+            Book.objects.create(title="Old Man and The Sea", author=author)
+
+            for book in Book.objects.all():
+                book.new_title = book.title
+                book.save()
+
+        def test_prefetch(models, schema_editor):
+            Author = models.get_model("test_authors", "Author")
+            authors = Author.objects.all().prefetch_related('book_set')
+            assert authors[0].book_set.all()[0].new_title == "Old Man and The Sea"
+
+        create_author = migrations.CreateModel(
+            "Author",
+            [
+                ("id", models.AutoField(primary_key=True)),
+                ("name", models.CharField(max_length=100)),
+            ],
+            options={},
+        )
+        create_book = migrations.CreateModel(
+            "Book",
+            [
+                ("id", models.AutoField(primary_key=True)),
+                ("title", models.CharField(max_length=100)),
+                ("new_title", models.CharField(max_length=100)),
+                ("author", models.ForeignKey("test_authors.Author"))
+            ],
+            options={},
+        )
+        create_old_man = migrations.RunPython(create_old_man)
+        delete_book_title = migrations.RemoveField("Book", "title")
+        test_prefetch = migrations.RunPython(test_prefetch)
+
+        project_state = ProjectState()
+        new_state = project_state.clone()
+        with connection.schema_editor() as editor:
+            create_author.state_forwards("test_authors", new_state)
+            create_author.database_forwards("test_authors", editor, project_state, new_state)
+        project_state = new_state
+        new_state = new_state.clone()
+        with connection.schema_editor() as editor:
+            create_book.state_forwards("test_books", new_state)
+            create_book.database_forwards("test_books", editor, project_state, new_state)
+        project_state = new_state
+        new_state = new_state.clone()
+        with connection.schema_editor() as editor:
+            create_old_man.state_forwards("test_books", new_state)
+            create_old_man.database_forwards("test_books", editor, project_state, new_state)
+        with connection.schema_editor() as editor:
+            delete_book_title.state_forwards("test_books", new_state)
+            delete_book_title.database_forwards("test_books", editor, project_state, new_state)
+        project_state = new_state
+        new_state = new_state.clone()
+        with connection.schema_editor() as editor:
+            test_prefetch.state_forwards("test_books", new_state)
+            test_prefetch.database_forwards("test_books", editor, project_state, new_state)
+
+
     def test_run_python_noop(self):
         """
         #24098 - Tests no-op RunPython operations.