Ticket #30152: testcase_and_rough_fix.patch

django/db/backends/base/schema.py

@@ -32 +32 @@
     # Filter out m2m objects from reverse relations.
     # Return (old_relation, new_relation) tuples.
     return zip(
-        (obj for obj in old_field.model._meta.related_objects if _is_relevant_relation(obj, old_field)),
-        (obj for obj in new_field.model._meta.related_objects if _is_relevant_relation(obj, new_field))
+        (obj for obj in old_field.model._meta._get_fields(forward=False, reverse=True, include_hidden=True) if _is_relevant_relation(obj, old_field)),
+        (obj for obj in new_field.model._meta._get_fields(forward=False, reverse=True, include_hidden=True) if _is_relevant_relation(obj, new_field)),
     )
 
 
@@ -743 +743 @@
             self.execute(self._create_fk_sql(model, new_field, "_fk_%(to_table)s_%(to_column)s"))
         # Rebuild FKs that pointed to us if we previously had to drop them
         if drop_foreign_keys:
-            for rel in new_field.model._meta.related_objects:
+            for rel in new_field.model._meta._get_fields(forward=False, reverse=True, include_hidden=True):
                 if _is_relevant_relation(rel, new_field) and rel.field.db_constraint:
                     self.execute(self._create_fk_sql(rel.related_model, rel.field, "_fk"))
         # Does it have check constraints we need to add?

tests/migrations/test_operations.py

@@ -1458 +1458 @@
             operation.database_backwards("test_alflpkfk", editor, new_state, project_state)
         assertIdTypeEqualsFkType()
 
+    @skipUnlessDBFeature('supports_foreign_keys')
+    def test_alter_field_pk_m2m(self):
+        """
+        Tests the AlterField operation on primary keys changes any FKs pointing to it.
+        """
+        project_state = self.set_up_test_model("test_alflpkm2m", second_model=True)
+
+        project_state = self.apply_operations("test_alflpkm2m", project_state, operations=[
+            migrations.AddField(
+                "Pony", "stables",
+                models.ManyToManyField("Stable", related_name="ponies")
+            )
+        ])
+
+        # Test the state alteration
+        operation = migrations.AlterField("Pony", "id", models.FloatField(primary_key=True))
+        new_state = project_state.clone()
+        operation.state_forwards("test_alflpkm2m", new_state)
+        self.assertIsInstance(project_state.models["test_alflpkm2m", "pony"].get_field_by_name("id"), models.AutoField)
+        self.assertIsInstance(new_state.models["test_alflpkm2m", "pony"].get_field_by_name("id"), models.FloatField)
+
+        def assertIdTypeEqualsFkType():
+            with connection.cursor() as cursor:
+                id_type, id_null = [
+                    (c.type_code, c.null_ok)
+                    for c in connection.introspection.get_table_description(cursor, "test_alflpkm2m_pony")
+                    if c.name == "id"
+                ][0]
+                fk_type, fk_null = [
+                    (c.type_code, c.null_ok)
+                    for c in connection.introspection.get_table_description(cursor, "test_alflpkm2m_pony_stables")
+                    if c.name == "pony_id"
+                ][0]
+            self.assertEqual(id_type, fk_type)
+            self.assertEqual(id_null, fk_null)
+
+        assertIdTypeEqualsFkType()
+        # Test the database alteration
+        with connection.schema_editor() as editor:
+            operation.database_forwards("test_alflpkm2m", editor, project_state, new_state)
+        assertIdTypeEqualsFkType()
+        # And test reversal
+        with connection.schema_editor() as editor:
+            operation.database_backwards("test_alflpkm2m", editor, new_state, project_state)
+        assertIdTypeEqualsFkType()
+
+    @skipUnlessDBFeature('supports_foreign_keys')
+    def test_alter_field_pk_m2m_through(self):
+        """
+        Tests the AlterField operation on primary keys changes any FKs pointing to it.
+        """
+        project_state = self.set_up_test_model("test_alflpkm2mthrough", second_model=True)
+
+        project_state = self.apply_operations("test_alflpkm2mthrough", project_state, operations=[
+            migrations.CreateModel("PonyStables", fields=[
+                ("pony", models.ForeignKey('test_alflpkm2mthrough.Pony', models.CASCADE)),
+                ("stable", models.ForeignKey('test_alflpkm2mthrough.Stable', models.CASCADE)),
+            ]),
+            migrations.AddField(
+                "Pony", "stables",
+                models.ManyToManyField("Stable", related_name="ponies", through='test_alflpkm2mthrough.PonyStables')
+            )
+        ])
+        self.assertTableExists("test_alflpkm2mthrough_ponystables")
+
+        # Test the state alteration
+        operation = migrations.AlterField("Pony", "id", models.FloatField(primary_key=True))
+        new_state = project_state.clone()
+        operation.state_forwards("test_alflpkm2mthrough", new_state)
+        self.assertIsInstance(project_state.models["test_alflpkm2mthrough", "pony"].get_field_by_name("id"), models.AutoField)
+        self.assertIsInstance(new_state.models["test_alflpkm2mthrough", "pony"].get_field_by_name("id"), models.FloatField)
+
+        def assertIdTypeEqualsFkType():
+            with connection.cursor() as cursor:
+                id_type, id_null = [
+                    (c.type_code, c.null_ok)
+                    for c in connection.introspection.get_table_description(cursor, "test_alflpkm2mthrough_pony")
+                    if c.name == "id"
+                ][0]
+                fk_type, fk_null = [
+                    (c.type_code, c.null_ok)
+                    for c in connection.introspection.get_table_description(cursor, "test_alflpkm2mthrough_ponystables")
+                    if c.name == "pony_id"
+                ][0]
+            self.assertEqual(id_type, fk_type)
+            self.assertEqual(id_null, fk_null)
+
+        assertIdTypeEqualsFkType()
+        # Test the database alteration
+        with connection.schema_editor() as editor:
+            operation.database_forwards("test_alflpkm2mthrough", editor, project_state, new_state)
+        assertIdTypeEqualsFkType()
+        # And test reversal
+        with connection.schema_editor() as editor:
+            operation.database_backwards("test_alflpkm2mthrough", editor, new_state, project_state)
+        assertIdTypeEqualsFkType()
+
+
     def test_alter_field_reloads_state_on_fk_target_changes(self):
         """
         If AlterField doesn't reload state appropriately, the second AlterField