Fixed #4049 -- Improved error handling in auth() context processor. Based on a patch from gregorth.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@6356 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/context_processors.py

@@ -13,11 +13,19 @@ def auth(request):
     """
     Returns context variables required by apps that use Django's authentication
     system.
+
+    If there is no 'user' attribute in the request, uses AnonymousUser (from
+    django.contrib.auth).
     """
+    if hasattr(request, 'user'):
+        user = request.user
+    else:
+        from django.contrib.auth.models import AnonymousUser
+        user = AnonymousUser()
     return {
-        'user': request.user,
-        'messages': request.user.get_and_delete_messages(),
-        'perms': PermWrapper(request.user),
+        'user': user,
+        'messages': user.get_and_delete_messages(),
+        'perms': PermWrapper(user),
     }
 
 def debug(request):