Fixed #18093 -- Added a pk to AnonymousUser.

django/contrib/auth/models.py

@@ -404,6 +404,7 @@ class User(models.Model):
 
 class AnonymousUser(object):
     id = None
+    pk = None
     username = ''
     is_staff = False
     is_active = False

django/contrib/auth/tests/basic.py

@@ -52,6 +52,7 @@ class BasicTestCase(TestCase):
     def test_anonymous_user(self):
         "Check the properties of the anonymous user"
         a = AnonymousUser()
+        self.assertEqual(a.pk, None)
         self.assertFalse(a.is_authenticated())
         self.assertFalse(a.is_staff)
         self.assertFalse(a.is_active)