Username is changed even form input is invalid (Symfony) - symfony

Question

Currently I am working on a recipe app in Symfony 6. So far so good. Right now I want to enable the user to change his username. The username is at the same time also the UserIdentifier.
The username can also be changed successfully. I have a constraint that sets the length of the username. However, the form with the invalid value is submitted anyway and the user is logged out.
Maybe I made a mistake somewhere, but I'm really getting desperate. Actually, the problem is quite simple, but I can't find the right solution.
Thank you very much for your help!
My Controller
`
<?php
namespace App\Controller;
use App\Form\ProfileUsernameType;
use App\Repository\UserRepository;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;
class ProfileChangeUsernameController extends AbstractController
{
#[Route('/profile/changeUsername')]
public function changeUsername(UserRepository $userRepository, EntityManagerInterface $entityManager, Request $request)
{
$user = $this->getUser()->getUserIdentifier();
$username = $userRepository->findOneBy(['username' => $user ]);
$form = $this->createForm(ProfileUsernameType::class, $username);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
$username->setUsername($form->get('username')->getData());
$entityManager->persist($username);
$entityManager->flush();
}
return $this->render('profile/changeUsername.html.twig', [
'form' => $form,
]);
}
}
`
My Form
`
<?php
namespace App\Form;
use App\Entity\User;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;
use Symfony\Component\Validator\Constraints\Length;
use Symfony\Component\Validator\Constraints\NotBlank;
class ProfileUsernameType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
->add('username', TextType::class,[
'data_class' => null,
'attr' => [
'placeholder' => 'Username',
'autocomplete' => 'off',
],
'constraints' => [
new NotBlank(),
new Length(['min' => 5])],
])
->add('submit', SubmitType::class, ['label' => 'Submit your username'])
->getForm();
;
}
public function configureOptions(OptionsResolver $resolver): void
{
$resolver->setDefaults([
'data_class' => User::class,
]);
}
}
`
My Twig file
`
{% extends 'base.html.twig' %}
{% form_theme form 'bootstrap_5_layout.html.twig' %}
{% block body %}
{{ form_start(form)}}
{{ form_errors(form) }}
{{ form_widget(form.username) }}
{{ form_row(form.submit) }}
{{ form_end(form) }}
{% endblock %}
`

Answer 1

I was facing the same problem some time ago and found this solution:
In your ProfileUsernameType.php, do it like this:
$builder
->add('username', TextType::class, [
'attr' => [
'class' => 'form-control',
'readonly' => 'readonly',
'value' =>$user['username']
],
'label' => 'Username: '
])