Refactored registration of models.

Got rid of AppConfig._stub. As a side effect, app_cache.app_configs now
only contains entries for applications that are in INSTALLED_APPS, which
is a good thing and will allow dramatic simplifications (which I will
perform in the next commit). That required adjusting all methods that
iterate on app_configs without checking the "installed" flag, hence the
large changes in get_model[s].

Introduced AppCache.all_models to store models:
- while the app cache is being populated and a suitable app config
  object to register models isn't available yet;
- for applications that aren't in INSTALLED_APPS since they don't have
  an app config any longer.

Replaced get_model(seed_cache=False) by registered_model() which can be
kept simple and safe to call at any time, and removed the seed_cache
argument to get_model[s]. There's no replacement for that private API.

Allowed non-master app caches to go through populate() as it is now
safe to do so. They were introduced in 1.7 so backwards compatibility
isn't a concern as long as the migrations framework keeps working.

1 files changed, 3 insertions, 0 deletions

diff --git a/tests/managers_regress/tests.py b/tests/managers_regress/tests.py
index f2897862ec..b9c8244612 100644
--- a/tests/managers_regress/tests.py
+++ b/tests/managers_regress/tests.py
@@ -128,6 +128,7 @@ class ManagersRegressionTests(TestCase):
 
         finally:
             app_cache.app_configs['managers_regress'].models = _old_models
+            app_cache.all_models['managers_regress'] = _old_models
             app_cache._get_models_cache = {}
 
     @override_settings(TEST_SWAPPABLE_MODEL='managers_regress.Parent')
@@ -155,6 +156,7 @@ class ManagersRegressionTests(TestCase):
 
         finally:
             app_cache.app_configs['managers_regress'].models = _old_models
+            app_cache.all_models['managers_regress'] = _old_models
             app_cache._get_models_cache = {}
 
     @override_settings(TEST_SWAPPABLE_MODEL='managers_regress.Parent')
@@ -182,6 +184,7 @@ class ManagersRegressionTests(TestCase):
 
         finally:
             app_cache.app_configs['managers_regress'].models = _old_models
+            app_cache.all_models['managers_regress'] = _old_models
             app_cache._get_models_cache = {}
 
     def test_regress_3871(self):