Symfony render required on TextField true - symfony

Question

I don't understand why the rendering of this subform doesn't render the required tag on my TextType firstName;
My form in based on a Order entity
OrderFormType has a CollectionType of Tent, based on TentFormType
TentFormType has a CollectionType of Camper, based on CamperFormType
So Order > Tent > Camper
namespace AppBundle\Form\Type;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
//...
class CamperFormType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('firstName', TextType::class, [
'required' => true, //Should even not been usefull since SF2.8
'label' => 'First name',
'attr' => [
'placeholder' => 'First name'
],
]);
//...
}
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults([
'data_class' => 'AppBundle\Entity\Camper',
'csrf_protection' => true,
'error_bubbling' => true,
'csrf_field_name' => '_token',
//...
]);
}
}
The fields are simply rendered with a form_widget:
{{ form_widget(form.firstName) }}
{{ form_widget(form.lastName) }}
But that not add the required field:
<input id="app_order_form_type_tents_0_campers_0_firstName" name="app_order_form_type[tents][0][campers][0][firstName]" placeholder="First name" class="form-control" type="text">
<input id="app_order_form_type_tents_0_campers_0_lastName" name="app_order_form_type[tents][0][campers][0][lastName]" placeholder="Last name" class="form-control" type="text">
I could do
{{ form_widget(form.firstName, {'attr': {'required': 'required'}}) }}
{{ form_widget(form.lastName, {'attr': {'required': 'required'}}) }}
But it shouldn't be required with my FormType...
Does anyone knows why ?
--EDIT--
My Camper Entity
<?php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;
/**
* Camper.
*
* #ORM\Table(name="camper")
* #ORM\Entity()
*/
class Camper
{
/**
* #var int
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var string
* #Assert\NotBlank()
*
* #ORM\Column(name="firstName", type="string", length=255, nullable=false)
*/
private $firstName;
// ...
}

Answer 1

I'm sorry, i can not use comments so i put a suggestion here...
Try:
{{ form_start(form) }}
{{ form_widget(form) }}
{{ form_end(form) }}