=== modified file 'includes/common.inc'
--- includes/common.inc	2009-02-02 15:42:43 +0000
+++ includes/common.inc	2009-02-02 21:48:31 +0000
@@ -1883,16 +1883,14 @@ function drupal_page_footer() {
  *   An associative array.
  */
 function drupal_map_assoc($array, $function = NULL) {
-  if (!isset($function) && !empty($array)) {
-    return array_combine($array, $array);
- }
-  elseif (function_exists($function)) {
-    $result = array();
-    foreach ($array as $value) {
-      $result[$value] = $function($value);
-    }
-    return $result;
+  if (empty($array)) {
+    return $array;
+  }
+  $keys = $array;
+  if ($function) {
+    array_walk($array, $function);
   }
+  return array_combine($keys, $array);
 }
 
 /**