Don't assign an ACL to a non existant holder

apps/acls/utils.py

@@ -7,15 +7,15 @@ from django.contrib.contenttypes.models import ContentType
 from common.models import AnonymousUserSingleton
 
 from .models import AccessEntry, DefaultAccessEntry, CreatorSingleton
-from .classes import EncapsulatedObject, AccessHolder, ClassAccessHolder
+from .classes import (EncapsulatedObject, AccessHolder, ClassAccessHolder,
+    get_source_object)
 
 logger = logging.getLogger(__name__)
 
 
 def apply_default_acls(obj, actor=None):
     logger.debug('actor, init: %s' % actor)
-    if isinstance(obj, EncapsulatedObject):
-        obj = obj.source_object
+    obj = get_source_object(obj)
 
     if actor:
         actor = AnonymousUserSingleton.objects.passthru_check(actor)
@@ -25,6 +25,8 @@ def apply_default_acls(obj, actor=None):
     for default_acl in DefaultAccessEntry.objects.filter(content_type=content_type):
         holder = CreatorSingleton.objects.passthru_check(default_acl.holder_object, actor)
        
+        if holder:
+            # When the creator is admin
             access_entry = AccessEntry(
                 permission=default_acl.permission,
                 holder_object=holder,