[1.7.x] Fixed #22750, #22248: Model renaming now also alters field FKs

3 files changed, 36 insertions, 69 deletions

diff --git a/tests/migrations/test_autodetector.py b/tests/migrations/test_autodetector.py
index 629acbd610..6d163873ad 100644
--- a/tests/migrations/test_autodetector.py
+++ b/tests/migrations/test_autodetector.py
@@ -75,9 +75,7 @@ class AutodetectorTests(TestCase):
         return output
 
     def assertNumberMigrations(self, changes, app_label, number):
-        if not changes.get(app_label, None):
-            self.fail("No migrations found for %s\n%s" % (app_label, self.repr_changes(changes)))
-        if len(changes[app_label]) != number:
+        if len(changes.get(app_label, [])) != number:
             self.fail("Incorrect number of migrations (%s) for %s (expected %s)\n%s" % (
                 len(changes[app_label]),
                 app_label,
@@ -283,7 +281,7 @@ class AutodetectorTests(TestCase):
         changes = autodetector._detect_changes()
 
         # Right number of migrations for model rename?
-        self.assertEqual(len(changes['testapp']), 1)
+        self.assertNumberMigrations(changes, 'testapp', 1)
         # Right number of actions?
         migration = changes['testapp'][0]
         self.assertEqual(len(migration.operations), 1)
@@ -292,17 +290,9 @@ class AutodetectorTests(TestCase):
         self.assertEqual(action.__class__.__name__, "RenameModel")
         self.assertEqual(action.old_name, "Author")
         self.assertEqual(action.new_name, "Writer")
-
-        # Right number of migrations for related field rename?
-        self.assertEqual(len(changes['otherapp']), 1)
-        # Right number of actions?
-        migration = changes['otherapp'][0]
-        self.assertEqual(len(migration.operations), 1)
-        # Right action?
-        action = migration.operations[0]
-        self.assertEqual(action.__class__.__name__, "AlterField")
-        self.assertEqual(action.name, "author")
-        self.assertEqual(action.field.rel.to, "testapp.Writer")
+        # Now that RenameModel handles related fields too, there should be
+        # no AlterField for the related field.
+        self.assertNumberMigrations(changes, 'otherapp', 0)
 
     def test_rename_model_with_renamed_rel_field(self):
         """
@@ -314,9 +304,8 @@ class AutodetectorTests(TestCase):
         after = self.make_project_state([self.author_renamed_with_book, self.book_with_field_and_author_renamed])
         autodetector = MigrationAutodetector(before, after, MigrationQuestioner({"ask_rename_model": True, "ask_rename": True}))
         changes = autodetector._detect_changes()
-
         # Right number of migrations for model rename?
-        self.assertEqual(len(changes['testapp']), 1)
+        self.assertNumberMigrations(changes, 'testapp', 1)
         # Right number of actions?
         migration = changes['testapp'][0]
         self.assertEqual(len(migration.operations), 1)
@@ -325,21 +314,17 @@ class AutodetectorTests(TestCase):
         self.assertEqual(action.__class__.__name__, "RenameModel")
         self.assertEqual(action.old_name, "Author")
         self.assertEqual(action.new_name, "Writer")
-
         # Right number of migrations for related field rename?
-        self.assertEqual(len(changes['otherapp']), 1)
+        # Alter is already taken care of.
+        self.assertNumberMigrations(changes, 'otherapp', 1)
         # Right number of actions?
         migration = changes['otherapp'][0]
-        self.assertEqual(len(migration.operations), 2)
+        self.assertEqual(len(migration.operations), 1)
         # Right actions?
         action = migration.operations[0]
         self.assertEqual(action.__class__.__name__, "RenameField")
         self.assertEqual(action.old_name, "author")
         self.assertEqual(action.new_name, "writer")
-        action = migration.operations[1]
-        self.assertEqual(action.__class__.__name__, "AlterField")
-        self.assertEqual(action.name, "writer")
-        self.assertEqual(action.field.rel.to, "testapp.Writer")
 
     def test_fk_dependency(self):
         "Tests that having a ForeignKey automatically adds a dependency"
diff --git a/tests/migrations/test_base.py b/tests/migrations/test_base.py
index 2dba30b2aa..839929d087 100644
--- a/tests/migrations/test_base.py
+++ b/tests/migrations/test_base.py
@@ -46,3 +46,17 @@ class MigrationTestBase(TransactionTestCase):
 
     def assertIndexNotExists(self, table, columns):
         return self.assertIndexExists(table, columns, False)
+
+    def assertFKExists(self, table, columns, to, value=True):
+        with connection.cursor() as cursor:
+            self.assertEqual(
+                value,
+                any(
+                    c["foreign_key"] == to
+                    for c in connection.introspection.get_constraints(cursor, table).values()
+                    if c['columns'] == list(columns)
+                ),
+            )
+
+    def assertFKNotExists(self, table, columns, to, value=True):
+        return self.assertFKExists(table, columns, to, False)
diff --git a/tests/migrations/test_operations.py b/tests/migrations/test_operations.py
index 19d19e81b5..472d7b003e 100644
--- a/tests/migrations/test_operations.py
+++ b/tests/migrations/test_operations.py
@@ -245,68 +245,36 @@ class OperationTests(MigrationTestBase):
         """
         Tests the RenameModel operation.
         """
-        project_state = self.set_up_test_model("test_rnmo")
+        project_state = self.set_up_test_model("test_rnmo", related_model=True)
         # Test the state alteration
         operation = migrations.RenameModel("Pony", "Horse")
         new_state = project_state.clone()
         operation.state_forwards("test_rnmo", new_state)
         self.assertNotIn(("test_rnmo", "pony"), new_state.models)
         self.assertIn(("test_rnmo", "horse"), new_state.models)
+        # Remember, RenameModel also repoints all incoming FKs and M2Ms
+        self.assertEqual("test_rnmo.Horse", new_state.models["test_rnmo", "rider"].fields[1][1].rel.to)
         # Test the database alteration
         self.assertTableExists("test_rnmo_pony")
         self.assertTableNotExists("test_rnmo_horse")
+        if connection.features.supports_foreign_keys:
+            self.assertFKExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_pony", "id"))
+            self.assertFKNotExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_horse", "id"))
         with connection.schema_editor() as editor:
             operation.database_forwards("test_rnmo", editor, project_state, new_state)
         self.assertTableNotExists("test_rnmo_pony")
         self.assertTableExists("test_rnmo_horse")
+        if connection.features.supports_foreign_keys:
+            self.assertFKNotExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_pony", "id"))
+            self.assertFKExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_horse", "id"))
         # And test reversal
         with connection.schema_editor() as editor:
             operation.database_backwards("test_rnmo", editor, new_state, project_state)
-        self.assertTableExists("test_dlmo_pony")
+        self.assertTableExists("test_rnmo_pony")
         self.assertTableNotExists("test_rnmo_horse")
-
-    # See #22248 - this will fail until that's fixed.
-    #
-    # def test_rename_model_with_related(self):
-    #     """
-    #     Tests the real-world combo of a RenameModel operation with AlterField
-    #     for a related field.
-    #     """
-    #     project_state = self.set_up_test_model(
-    #         "test_rnmowr", related_model=True)
-    #     # Test the state alterations
-    #     model_operation = migrations.RenameModel("Pony", "Horse")
-    #     new_state = project_state.clone()
-    #     model_operation.state_forwards("test_rnmowr", new_state)
-    #     self.assertNotIn(("test_rnmowr", "pony"), new_state.models)
-    #     self.assertIn(("test_rnmowr", "horse"), new_state.models)
-
-    #     self.assertEqual(
-    #         "Pony",
-    #         project_state.render().get_model("test_rnmowr", "rider")
-    #         ._meta.get_field_by_name("pony")[0].rel.to._meta.object_name)
-    #     field_operation = migrations.AlterField(
-    #         "Rider", "pony", models.ForeignKey("Horse"))
-    #     field_operation.state_forwards("test_rnmowr", new_state)
-    #     self.assertEqual(
-    #         "Horse",
-    #         new_state.render().get_model("test_rnmowr", "rider")
-    #         ._meta.get_field_by_name("pony")[0].rel.to._meta.object_name)
-
-    #     # Test the database alterations
-    #     self.assertTableExists("test_rnmowr_pony")
-    #     self.assertTableNotExists("test_rnmowr_horse")
-    #     with connection.schema_editor() as editor:
-    #         model_operation.database_forwards("test_rnmowr", editor, project_state, new_state)
-    #         field_operation.database_forwards("test_rnmowr", editor, project_state, new_state)
-    #     self.assertTableNotExists("test_rnmowr_pony")
-    #     self.assertTableExists("test_rnmowr_horse")
-    #     # And test reversal
-    #     with connection.schema_editor() as editor:
-    #         field_operation.database_backwards("test_rnmowr", editor, new_state, project_state)
-    #         model_operation.database_backwards("test_rnmowr", editor, new_state, project_state)
-    #     self.assertTableExists("test_rnmowr_pony")
-    #     self.assertTableNotExists("test_rnmowr_horse")
+        if connection.features.supports_foreign_keys:
+            self.assertFKExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_pony", "id"))
+            self.assertFKNotExists("test_rnmo_rider", ["pony_id"], ("test_rnmo_horse", "id"))
 
     def test_add_field(self):
         """