Fixed #23728 -- Added the --exit option to makemigrations.

If no changes that need migrations are found, `makemigrations --exit`
exits with error code 1.

docs/ref/django-admin.txt

@@ -719,6 +719,14 @@ a merge.
 The ``--name`` option allows you to give the migration(s) a custom name instead
 of a generated one.
 
+.. django-admin-option:: --exit, -e
+
+.. versionadded:: 1.8
+
+The ``--exit`` option will cause ``makemigrations`` to exit with error code 1
+when no migration are created (or would have been created, if combined with
+``--dry-run``).
+
 migrate [<app_label> [<migrationname>]]
 ---------------------------------------
 

docs/releases/1.8.txt

@@ -333,6 +333,9 @@ Management Commands
   :setting:`FIXTURE_DIRS` contains duplicates or a default fixture directory
   path (``app_name/fixtures``), an exception is raised.
 
+* :djadmin:`makemigrations` now supports an :djadminopt:`--exit` option to
+  exit with an error code if no migrations are created.
+
 Middleware
 ^^^^^^^^^^