Fixed #23160 -- Correctly rename models with self referential fields.

Thanks to whitews AT gmail for the report.

django/db/migrations/operations/models.py

@@ -124,10 +124,14 @@ class RenameModel(Operation):
         del state.models[app_label, self.old_name.lower()]
         # Repoint the FKs and M2Ms pointing to us
         for related_object in (related_objects + related_m2m_objects):
-            related_key = (
-                related_object.model._meta.app_label,
-                related_object.model._meta.object_name.lower(),
-            )
+            # Use the new related key for self referential related objects.
+            if related_object.model == model:
+                related_key = (app_label, self.new_name.lower())
+            else:
+                related_key = (
+                    related_object.model._meta.app_label,
+                    related_object.model._meta.object_name.lower(),
+                )
             new_fields = []
             for name, field in state.models[related_key].fields:
                 if name == related_object.field.name:
@@ -152,12 +156,20 @@ class RenameModel(Operation):
             related_objects = old_model._meta.get_all_related_objects()
             related_m2m_objects = old_model._meta.get_all_related_many_to_many_objects()
             for related_object in (related_objects + related_m2m_objects):
+                if related_object.model == old_model:
+                    model = new_model
+                    related_key = (app_label, self.new_name.lower())
+                else:
+                    model = related_object.model
+                    related_key = (
+                        related_object.model._meta.app_label,
+                        related_object.model._meta.object_name.lower(),
+                    )
                 to_field = new_apps.get_model(
-                    related_object.model._meta.app_label,
-                    related_object.model._meta.object_name.lower(),
+                    *related_key
                 )._meta.get_field_by_name(related_object.field.name)[0]
                 schema_editor.alter_field(
-                    related_object.model,
+                    model,
                     related_object.field,
                     to_field,
                 )

tests/migrations/test_operations.py

@@ -111,6 +111,7 @@ class OperationTestBase(MigrationTestBase):
                 [
                     ("id", models.AutoField(primary_key=True)),
                     ("pony", models.ForeignKey("Pony")),
+                    ("friend", models.ForeignKey("self"))
                 ],
             ))
         if mti_model:
@@ -406,6 +407,42 @@ class OperationTests(OperationTestBase):
             self.assertFKExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_pony", "id"))
             self.assertFKNotExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_horse", "id"))
 
+    def test_rename_model_with_self_referential_fk(self):
+        """
+        Tests the RenameModel operation on model with self referential FK.
+        """
+        project_state = self.set_up_test_model("test_rmwsrf", related_model=True)
+        # Test the state alteration
+        operation = migrations.RenameModel("Rider", "HorseRider")
+        self.assertEqual(operation.describe(), "Rename model Rider to HorseRider")
+        new_state = project_state.clone()
+        operation.state_forwards("test_rmwsrf", new_state)
+        self.assertNotIn(("test_rmwsrf", "rider"), new_state.models)
+        self.assertIn(("test_rmwsrf", "horserider"), new_state.models)
+        # Remember, RenameModel also repoints all incoming FKs and M2Ms
+        self.assertEqual("test_rmwsrf.HorseRider", new_state.models["test_rmwsrf", "horserider"].fields[2][1].rel.to)
+        # Test the database alteration
+        self.assertTableExists("test_rmwsrf_rider")
+        self.assertTableNotExists("test_rmwsrf_horserider")
+        if connection.features.supports_foreign_keys:
+            self.assertFKExists("test_rmwsrf_rider", ["friend_id"], ("test_rmwsrf_rider", "id"))
+            self.assertFKNotExists("test_rmwsrf_horserider", ["friend_id"], ("test_rmwsrf_horserider", "id"))
+        with connection.schema_editor() as editor:
+            operation.database_forwards("test_rmwsrf", editor, project_state, new_state)
+        self.assertTableNotExists("test_rmwsrf_rider")
+        self.assertTableExists("test_rmwsrf_horserider")
+        if connection.features.supports_foreign_keys:
+            self.assertFKNotExists("test_rmwsrf_rider", ["friend_id"], ("test_rmwsrf_rider", "id"))
+            self.assertFKExists("test_rmwsrf_horserider", ["friend_id"], ("test_rmwsrf_horserider", "id"))
+        # And test reversal
+        with connection.schema_editor() as editor:
+            operation.database_backwards("test_rmwsrf", editor, new_state, project_state)
+        self.assertTableExists("test_rmwsrf_rider")
+        self.assertTableNotExists("test_rmwsrf_horserider")
+        if connection.features.supports_foreign_keys:
+            self.assertFKExists("test_rmwsrf_rider", ["friend_id"], ("test_rmwsrf_rider", "id"))
+            self.assertFKNotExists("test_rmwsrf_horserider", ["friend_id"], ("test_rmwsrf_horserider", "id"))
+
     def test_add_field(self):
         """
         Tests the AddField operation.