Ticket #13416: django_ticket_13416.diff

django/db/models/base.py

@@ -606 +606 @@
             else:
                 # m2m-ish but with no through table? GenericRelation: cascade delete
                 for sub_obj in f.value_from_object(self).all():
-                    # Generic relations not enforced by db constraints, thus we can set
-                    # nullable=True, order does not matter
-                    sub_obj._collect_sub_objects(seen_objs, self, True)
+                    # Generic relations not enforced by db constraints, but don't
+                    # set nullable=True because post_delete hook might rely on
+                    # parent object being in db.
+                    sub_obj._collect_sub_objects(seen_objs, self, False)
 
         # Handle any ancestors (for the model-inheritance case). We do this by
         # traversing to the most remote parent classes -- those with no parents