对symfony表单集合进行验证失败后，将良好的数据保留在表单中

Question

I have a form with a dynamic form collection. The point is that I don't want to allow the user to remove specific entries (that are modified in another part of the app). So I added a specific validation constraint that works: the form is not valid if I remove an element that is not "deletable".

The problem is that, as the element was removed in what the user submitted, the element is not in the form anymore, and after submit form data is locked.

Here is an example to show the problem:

class AppointmentController extends Controller
{

    public function editAppointment(Request $request, Appointment $appointment)
    {
        // Here
        // count($appointment->getSlot()) === 3

        $form = $this->createForm('appointment', $appointment, [
            'questionnaire' => $questionnaire
        ]);
        $form->handleRequest($request);

        if ($form->isValid()) {
            // Persisting
        }

        // Here on failing validation, there is
        // count($appointment->getSlot()) === 2
        // Because we removed one slot from "dynamically" in the form, but the user can't do that,
        // so we need to reset the slots but it's not possible because form data is locked after "submit".
        return $this->render('App:Appointment:edit.html.twig', ['form' => $form->createView()]);
    }
}

class AppointmentType extends AbstractTYpe
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('slots', 'collection', [
                'type' => new SlotType(),
                'allow_add' => true,
                'prototype' => true,
                'allow_delete' => true,
                'error_bubbling' => false,
                'by_reference' => false,
                'constraints' => [
                    new WrongSlotRemoval($builder->getData()->getSlots())
                ]
            ])
        ;
    }
}

class WrongSlotRemoval extends Constraint
{
    public $message = 'Impossible to delete slog.';

    /**
     * @var null|\App\Entity\AppointmentSlot[]
     */
    private $slots;

    /**
     * @param \App\Entity\AppointmentSlot[]|null $slots
     */
    public function __construct($slots = null)
    {
        // Clone the collection because it can be modified by reference
        // in order to add or delete items.
        if ($slots !== null) {
            $this->slots = clone $slots;
        }
    }

    /**
     * @return \App\Entity\AppointmentSlot[]
     */
    public function getSlots()
    {
        return $this->slots;
    }

    /**
     * @param \App\Entity\AppointmentSlot[] $slots
     * @return self
     */
    public function setSlots($slots)
    {
        $this->slots = $slots;

        return $this;
    }
}

class WrongSlotRemovalValidator extends ConstraintValidator
{
    /**
     * @param \App\Entity\AppointmentSlot[] $object
     * @param WrongSlotRemoval $constraint
     */
    public function validate($object, Constraint $constraint)
    {
        foreach($constraint->getSlots() as $slot) {
            if (!$object->contains($slot) && !$slot->isDeletable()) {

                $this->context
                    ->buildViolation($constraint->message)
                    ->addViolation()
                ;

                return;
            }
        }
    }
}

Any idea about how to modify form data after submit ?

Here is a screen of the problem: http://file.nekland.fr/dev/pb_form_collection.jpeg

Answer 1

This is a Symfony limitation: https://github.com/symfony/symfony/issues/5480

A workaround exists: re-creating the form and copy errors of each node of the form to the new form (that contains good data).

My solution will be to throw an error in the validator because the user is not able to remove an item (the cross is disabled), so he hacked the system. Showing an error is not a problem.