Symfony 4.4 User checker on login process not triggered - symfony

Question

I am implementing user registration process on Symfony 4.4 (without bundle) and I am stuck at the last step.
So far, this is what I have done:
Registration form is created
When user submit registration form he is well added to the database. A field activation token in user entity is fullfill.
An email with the activation token as parameter is automatically send to the user to activate his account
If the user click on the link, activation token field is set to 'null' in the user entity
In a user checker I check if the activation token is null
If activation token is not null I need to refuse the login and redirect the user to homepage with a flash message :I am stuck on this part, my User checker is not triggered. User can login with token not null.
Here is my user checker:
namespace App\Security;
use App\Exception\AccountDeletedException;
use App\Security\User as AppUser;
use Symfony\Component\Security\Core\Exception\AccountExpiredException;
use Symfony\Component\Security\Core\User\UserCheckerInterface;
use Symfony\Component\Security\Core\User\UserInterface;
use Symfony\Component\Security\Core\Exception\DisabledException;
class UserChecker implements UserCheckerInterface
{
public function checkPreAuth(UserInterface $user)
{
if (!$user instanceof AppUser) {
return;
}
// User account is not validated
if ($user->getValidationToken() !== null) {
throw new DisabledException('User account is not activated');
}
}
public function checkPostAuth(UserInterface $user)
{
if (!$user instanceof AppUser) {
return;
}
// user account is expired, the user may be notified
if ($user->isExpired()) {
throw new AccountExpiredException('...');
}
}
}
Security.yalm:
security:
encoders:
App\Entity\User:
algorithm: auto
# https://symfony.com/doc/current/security.html#where-do-users-come-from-user-providers
providers:
# used to reload user from session & other features (e.g. switch_user)
app_user_provider:
entity:
class: App\Entity\User
property: email
firewalls:
dev:
pattern: ^/(_(profiler|wdt)|css|images|js)/
security: false
main:
anonymous: lazy
provider: app_user_provider
guard:
authenticators:
- App\Security\AppCustomAuthenticator
logout:
path: app_logout
user_checker: App\Security\UserChecker

Answer 1

Change :
use App\Security\User as AppUser
To
use App\Entity\User as AppUser;
(or whatever namespace you have on your User class)
Side note : on preAuth, you can check for the presence of the token and not if valid or not since the auth is not passed... this should be done on real Authentification, or post it...