Ticket #3323: django.db.models.options.rev6263.diff

django/db/models/options.py

@@ -186 +186 @@
             rel_objs = []
             for klass in get_models():
                 for f in klass._meta.many_to_many:
+                    if f.rel and isinstance(f.rel.to, str):
+                        raise Exception("class %s has unresolved string relation" % klass)
                     if f.rel and self == f.rel.to._meta:
                         rel_objs.append(RelatedObject(f.rel.to, klass, f))
             if app_cache_ready():