Symfony2 security token cleared after redirect - security

Question

I have built a login form, with a custom provider which successfully sets the auth token.
I can see the "logged in as" in the profiler, while on the redirect interception page. The form then redirects to my success page.
For some reason, my success page, doesn't recognise that I'm logged in and loops back to the login page.
security:
encoders:
EP\Common\Entity\User: sha1
encode_as_base64: false
role_hierarchy:
ROLE_ADMIN: ROLE_USER
ROLE_SUPER_ADMIN: [ROLE_USER, ROLE_ADMIN, ROLE_ALLOWED_TO_SWITCH]
providers:
main:
entity: { class EP\Common\Entity\User, property: username }
firewalls:
dev:
pattern: ^/(_(profiler|wdt)|css|images|js)/
security: false
login_form:
pattern: ^/cms/(login|logout)$
security: false
cms:
pattern: ^/cms/
security: true
provider: main
form_login:
check_path: /cms/login_check
login_path: /cms/login
logout:
path: /cms/logout
target: /cms/login
access_control:
- { path: ^/cms/login, roles: IS_AUTHENTICATED_ANONYMOUSLY, requires_channel: http }
- { path: /cms, roles: ROLE_USER }

Answer 1

I've discovered why this is.
I'd added these methods to my User class (notice the [0] on unserialize - doctrine was looking for the ID of the user based on the first character of the ID):
/**
* (PHP 5 >= 5.1.0)<br/>
* String representation of object
* #link http://php.net/manual/en/serializable.serialize.php
* #return string the string representation of the object or null
*/
public function serialize()
{
return serialize($this->getId());
}
/**
* (PHP 5 >= 5.1.0)<br/>
* Constructs the object
* #link http://php.net/manual/en/serializable.unserialize.php
* #param string $serialized <p>
* The string representation of the object.
* </p>
* #return mixed the original value unserialized.
*/
public function unserialize($serialized)
{
$this->_uuid = unserialize($serialized)[0];
}