Ticket #1562: extend-1562.diff

core.js

@@ -579 +579 @@
                     continue;
 
                 // Recurse if we're merging object values
-                if ( deep && copy && typeof copy == "object" && src && !copy.nodeType )
-                    target[ name ] = jQuery.extend( deep, src, copy );
+                if ( deep && copy && typeof copy == "object" && !copy.nodeType )
+                    target[ name ] = jQuery.extend( deep, 
+                        // Never move original objects, clone them
+                        src || copy.length !== undefined ? [ ] : { }
+                    , copy );
 
                 // Don't bring in undefined values
                 else if ( copy !== undefined )