Error: Uninitialized string offset: 0 in menu_get_object()

In some cases when path is not exiting ie it should return 404 the key for that path 'cache_menu:menu_item:hash:serialized' , where hash is the hashed path returns an empty string. This confuses the output and throws error like:

Notice: Uninitialized string offset: 0 in menu_get_object() (line 956 of /home/vivek/projects/cse/work/iep/public_html/includes/menu.inc).

This can be fixed if the line number 27 in the file lib/Redis/Cache/Predis.php is changed from :

if (!isset($serialized)) {

to :

if (empty($serialized)) {