Index: includes/common.inc
===================================================================
--- includes/common.inc (revision 556)
+++ includes/common.inc (working copy)
@@ -1366,6 +1366,7 @@
  * alternative than url().
  */
 function url($path = NULL, $options = array()) {
+$options = is_array($options) ? $options : array(); // validate $options input
   // Merge in defaults.
   $options += array(
     'fragment' => '',