bug 564353, no more race conditions or any errors.

apps/cake/backends.py

@@ -2,6 +2,7 @@ import logging
 from time import time
 
 from django.contrib.auth.models import User
+from django.db import IntegrityError
 
 import phpserialize
 
@@ -55,7 +56,15 @@ class SessionBackend:
             # Chances are we are suffering from replication lag, but
             # let's play it safe and just not authenticate.
             return None
+        except IntegrityError, e:
+            # Typically a duplicate key.
+            log.warning('DB Error for UserProfile {0}: {1}'.format(user_id, e))
+            return None
 
+        except Exception, e:
+            log.error('Unknown exception for UserProfile {0}: {1}'.format(
+                    user_id, e))
+            return None
 
         return profile.user
 

apps/cake/tests.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 from django.contrib.auth.models import AnonymousUser, User
+from django.db import IntegrityError
 
 from mock import Mock, patch
 from nose.tools import eq_
@@ -91,7 +92,7 @@ class CakeTestCase(TestCase):
 
     @patch('django.db.models.fields.related.'
            'ReverseSingleRelatedObjectDescriptor.__get__')
-    def test_bad_user_id(self, p_mock):
+    def test_backend_profile_exceptions(self, p_mock):
         # We have a legitimate profile, but for some reason the user_id is phony
         s = SessionBackend()
         backend = SessionBackend()
@@ -100,6 +101,13 @@ class CakeTestCase(TestCase):
         p_mock.side_effect = User.DoesNotExist()
         eq_(None, s.authenticate(session))
 
+        p_mock.side_effect = IntegrityError()
+        eq_(None, s.authenticate(session))
+
+        p_mock.side_effect = Exception()
+        eq_(None, s.authenticate(session))
+
+
 
 class TestHelpers(TestCase):