Rewrote portions of the app- and model-cache initialisation to handle some…

Rewrote portions of the app- and model-cache initialisation to handle some corner cases. It is now possible to use m2m relations before everything is imported and still get the right results later when importing is complete. Also, get_apps() should always return the same results, so apps won't randomly disappear in the admin interface.

Also reorganised the structure of loading.py, since the number of global variables was exploding. The public API is still backwards compatible.

Fixed #1796 and #2438 (he claims, optimistically).


git-svn-id: http://code.djangoproject.com/svn/django/trunk@5919 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/options.py

@@ -2,7 +2,7 @@ from django.conf import settings
 from django.db.models.related import RelatedObject
 from django.db.models.fields.related import ManyToManyRel
 from django.db.models.fields import AutoField, FieldDoesNotExist
-from django.db.models.loading import get_models
+from django.db.models.loading import get_models, cache_ready
 from django.db.models.query import orderlist2sql
 from django.db.models import Manager
 from django.utils.translation import activate, deactivate_all, get_language, string_concat
@@ -179,7 +179,8 @@ class Options(object):
                 for f in klass._meta.many_to_many:
                     if f.rel and self == f.rel.to._meta:
                         rel_objs.append(RelatedObject(f.rel.to, klass, f))
-            self._all_related_many_to_many_objects = rel_objs
+            if cache_ready():
+                self._all_related_many_to_many_objects = rel_objs
             return rel_objs
 
     def get_ordered_objects(self):