Fixed #24919 -- Allowed disabling of migrations on a per app basis

django/db/migrations/loader.py

@@ -66,6 +66,9 @@ class MigrationLoader(object):
         for app_config in apps.get_app_configs():
             # Get the migrations module directory
             module_name = self.migrations_module(app_config.label)
+            if module_name is None:
+                self.unmigrated_apps.add(app_config.label)
+                continue
             was_loaded = module_name in sys.modules
             try:
                 module = import_module(module_name)

docs/ref/settings.txt

@@ -1862,6 +1862,15 @@ In this case, migrations pertaining to the ``blog`` app will be contained in the
 If you provide the ``app_label`` argument, :djadmin:`makemigrations` will
 automatically create the package if it doesn't already exist.
 
+.. versionadded:: 1.9
+
+When you supply ``None`` as a value for an app, Django will consider the app as
+an app without migrations regardless of an existing ``migrations`` submodule.
+This can be used, for example, in a test settings file to skip migrations while
+testing (tables will still be created for the apps' models). If this is used in
+your general project settings, remember to use the migrate
+:djadminopt:`--run-syncdb` option if you want to create tables for the app.
+
 .. setting:: MONTH_DAY_FORMAT
 
 MONTH_DAY_FORMAT

docs/releases/1.9.txt

@@ -446,6 +446,9 @@ Migrations
 
 * Added support for serialization of ``functools.partial`` objects.
 
+* When supplying ``None`` as a value in :setting:`MIGRATION_MODULES`, Django
+  will consider the app an app without migrations.
+
 Models
 ^^^^^^
 

tests/migrations/test_loader.py

@@ -179,6 +179,29 @@ class LoaderTests(TestCase):
                 "App missing __init__.py in migrations module not in unmigrated apps."
             )
 
+    @override_settings(
+        INSTALLED_APPS=['migrations.migrations_test_apps.migrated_app'],
+    )
+    def test_marked_as_migrated(self):
+        """
+        Undefined MIGRATION_MODULES implies default migration module.
+        """
+        migration_loader = MigrationLoader(connection)
+        self.assertEqual(migration_loader.migrated_apps, {'migrated_app'})
+        self.assertEqual(migration_loader.unmigrated_apps, set())
+
+    @override_settings(
+        INSTALLED_APPS=['migrations.migrations_test_apps.migrated_app'],
+        MIGRATION_MODULES={"migrated_app": None},
+    )
+    def test_marked_as_unmigrated(self):
+        """
+        MIGRATION_MODULES allows disabling of migrations for a particular app.
+        """
+        migration_loader = MigrationLoader(connection)
+        self.assertEqual(migration_loader.migrated_apps, set())
+        self.assertEqual(migration_loader.unmigrated_apps, {'migrated_app'})
+
     @override_settings(MIGRATION_MODULES={"migrations": "migrations.test_migrations_squashed"})
     def test_loading_squashed(self):
         "Tests loading a squashed migration"