Symfony 4 - The key "_username" must be a string, "NULL" given

Question

my project symfony 4 I have a function that serves me for authentication but also for registration:

/**
     * Login
     *
     * @Route("/login", name="account_login")
     * 
     * @return Response
     */
    public function login2(AuthenticationUtils $utils, Request $request, ObjectManager $manager, UserPasswordEncoderInterface $encoder)
    {
        // Connexion
        $error = $utils->getLastAuthenticationError();
        $username = $utils->getLastUsername();

        // Inscription
        $user = new User();
        $form = $this->createForm(RegistrationType::class, $user);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $password = $encoder->encodePassword($user, $user->getPassword());
            $user->setHash($password);
            $manager->persist($user);
            $manager->flush();

            $this->addFlash(
                'success',
                'Votre compte a bien été créé ! Vous pouvez maintenant vous connecter'
            );

            $this->redirectToRoute('account_login');
        }


        return $this->render('security/login.html.twig', [
            'hasError' => $error !== null,
            'username' => $username,
            'form' => $form->createView(),
        ]);
    }

So in my twig file I have my login form:

<form id="login-form" action="{{path('account_login')}}" method="post" role="form" style="display: block;">
     <div class="form-group">
          <label for="username">Email</label>
          <input type="text" name="_username" id="username" tabindex="1" class="form-control" placeholder="Adresse email" required value={{username}}>
     </div>
     <div class="form-group">
         <label for="password">Mot de passe</label>
         <input type="password" name="_password" id="password" tabindex="2" class="form-control" placeholder="Mot de passe">
     </div>
</form>

And my registration form :

{{form_start(form)}}
{{form_widget(form)}}
{{form_end(form)}}

But when I submit my registration form, I've this error :

The key "_username" must be a string, "NULL" given.

In my security.yml I've :

form_login:
        login_path: account_login
        check_path: account_login
        default_target_path: absence_index

      logout:
        path: account_logout
        target: account_login

I found this post : The key "_username" must be a string, "NULL" given symfony 4

It's the same problem I think, but I don't understand what's the solution.

Answer 1

mixing login and registration on one route is weird ... and I'm quite sure it won't work (without much hassle that is), because the framework already handles the request. (as in: it has some "form" that handles the request and produces errors)

However, you don't actually have to put it on one route ... just set the action on the registration and login form to the appropriate route and use the same templates.