Index: update.php
===================================================================
RCS file: /cvs/drupal/drupal/update.php,v
retrieving revision 1.293
diff -u -p -r1.293 update.php
--- update.php	29 Jul 2009 05:59:59 -0000	1.293
+++ update.php	29 Jul 2009 22:54:28 -0000
@@ -363,6 +363,10 @@ if (empty($op) && $update_access_allowed
   // Set up theme system for the maintenance page.
   drupal_maintenance_theme();
 
+  // Rebuild the registry to ensure that removed hooks in modules do not result
+  // in undefined function errors and that newly defined hooks are called.
+  registry_rebuild();
+
   // Check the update requirements for Drupal.
   update_check_requirements();