Guard against trying to use .is_authenticated() on a plain string. The error condition can occur when an exception has been triggered before the auth middleware has run. Related to ietf-tools#767 and ietf-tools#768.

 - Legacy-Id: 4052

Author: levkowetz

ietf/idtracker/templatetags/ietf_filters.py

@@ -453,7 +453,7 @@ def format_history_text(text):
 @register.filter
 def user_roles_json(user):
     roles = {}
-    if user.is_authenticated():
+    if not isinstance(user, basestring) and user.is_authenticated():
         if settings.USE_DB_REDESIGN_PROXY_CLASSES:
             from ietf.group.models import Role
             for r in Role.objects.filter(person__user=user).select_related(depth=1):