Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.320
diff -u -r1.320 bootstrap.inc
--- includes/bootstrap.inc	2 Nov 2009 03:46:43 -0000	1.320
+++ includes/bootstrap.inc	2 Nov 2009 21:49:38 -0000
@@ -2032,9 +2032,13 @@
   // Reset a single value, or all values.
   if ($reset) {
     if (isset($name)) {
-      unset($data[$name]);
+      $data[$name] = NULL; // Set data to NULL
+      unset($data[$name]); // Remove reference
     }
     else {
+      foreach (array_keys($data) as $name) {
+        $data[$name] = NULL; // Set data to NULL
+      }
       $data = array();
     }
     // We must return a reference to a variable.
Index: includes/module.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/module.inc,v
retrieving revision 1.164
diff -u -r1.164 module.inc
--- includes/module.inc	1 Nov 2009 22:10:07 -0000	1.164
+++ includes/module.inc	2 Nov 2009 21:49:38 -0000
@@ -367,7 +367,13 @@
  * @see module_implements_write_cache().
  */
 function module_implements($hook, $sort = FALSE, $reset = FALSE) {
-  $implementations = &drupal_static(__FUNCTION__, array());
+  // Use a static variable to store a reference to drupal_static()'s data so
+  // drupal_static() only needs to be called once.
+  static $cache = array();
+  if (!isset($cache['implementations'])) {
+   $cache['implementations'] = &drupal_static(__FUNCTION__, array());
+  }
+  $implementations = &$cache['implementations'];
 
   // We maintain a persistent cache of hook implementations in addition to the
   // static cache to avoid looping through every module and every hook on each