Description:
------------
There is a problem in the redis 3.1 extension in php 7+, when redis is used as a session handler. The problem only manifests itself when new session is being created, and has to do with php7 expecting a String. Please reference a related bug: https://bugs.php.net/bug.php?id=71187 which is for Memcached but Redis seems to have the same issue.

The following php workaround fixed the problem:

class RedisSession extends SessionHandler
{
        public function read($session_id) {
                return (string)parent::read($session_id);
        }
}

$sess = new RedisSession();
session_set_save_handler($sess, true);

Test script:
---------------
in php.ini i have:

session.save_handler = redis
session.save_path = "tcp://localhost:6379?weight=1"

in test.php i have:

session_start();

Expected result:
----------------
I would expect new session to be initialized.


Actual result:
--------------
Warning: session_start(): Failed to read session data: redis (path: tcp://local