Merge form CollectionType with existing collection - symfony

Question

I would need some help about management of CollectionType. In order to make my question as clear as possible, I will change my situation to fit the official Symfony documentation, with Tasks and Tags.
What I would like :
A existing task have alrady some tags assigned to it
I want to submit a list of tags with an additional field (value)
If the submitted tags are already assigned to the task->tags collection, I want to update them
It they are not, I want to add them to the collection with the submitted values
Existing tags, no part of the form, must be kept
Here is the problem :
All task tags are always overwritten by submitted data, including bedore the handleRequest method is called in the controller.
Therefore, I can't even compare the existing data using the repository, since this one already contains the collection sent by the form, even at the top of the update function in the controller.
Entity wize, this is a ManyToMany relation with an additional field (called value), so in reality, 2 OneToMany relations. Here are the code :
Entity "Task"
class Task
{
#[ORM\Id]
#[ORM\GeneratedValue]
#[ORM\Column]
private ?int $id = null;
#[ORM\OneToMany(mappedBy: 'task', targetEntity: TaskTags::class, orphanRemoval: false, cascade: ['persist'])]
private Collection $TaskTags;
/**
* #return Collection<int, TaskTags>
*/
public function getTaskTags(): Collection
{
return $this->TaskTags;
}
public function addTaskTag(TaskTags $TaskTag): self
{
// I have voluntarily remove the presence condition during my tests
$this->TaskTags->add($TaskTag);
$TaskTag->setTask($this);
return $this;
}
public function removeTaskTag(TaskTags $TaskTag): self
{
if ($this->TaskTags->removeElement($TaskTag)) {
// set the owning side to null (unless already changed)
if ($TaskTag->getTask() === $this) {
$TaskTag->setTask(null);
}
}
return $this;
}
}
Entity "Tag"
class Tag
{
#[ORM\Id]
#[ORM\GeneratedValue]
#[ORM\Column]
private ?int $id = null;
#[ORM\OneToMany(mappedBy: 'tag', targetEntity: TaskTags::class, orphanRemoval: false)]
private Collection $TaskTags;
/**
* #return Collection<int, TaskTags>
*/
public function getTaskTags(): Collection
{
return $this->TaskTags;
}
public function addTaskTag(TaskTags $TaskTag): self
{
$this->TaskTags->add($TaskTag);
$TaskTag->setTag($this);
return $this;
}
public function removeTaskTag(TaskTags $TaskTag): self
{
if ($this->TaskTags->removeElement($TaskTag)) {
// set the owning side to null (unless already changed)
if ($TaskTag->getTag() === $this) {
$TaskTag->setTag(null);
}
}
return $this;
}
}
Entity "TaskTags"
class TaskTags
{
#[ORM\Id]
#[ORM\ManyToOne(inversedBy: 'TaskTags')]
#[ORM\JoinColumn(nullable: false)]
private Task $task;
#[ORM\Id]
#[ORM\ManyToOne(inversedBy: 'TaskTags')]
#[ORM\JoinColumn(nullable: false)]
private Tag $tag;
// The addional field
#[ORM\Column(nullable: true)]
private ?int $value = null;
public function getTask(): ?Task
{
return $this->task;
}
public function setTask(?Task $task): self
{
if(null !== $task) {
$this->task = $task;
}
return $this;
}
public function getTag(): ?Tag
{
return $this->tag;
}
public function setTag(?Tag $tag): self
{
if(null !== $tag) {
$this->tag = $tag;
}
return $this;
}
public function getValue(): ?string
{
return $this->value;
}
public function setValue(?string $value): self
{
$this->value = $value;
return $this;
}
}
FormType "TaskFormType"
class TaskFormType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
...
->add('TaskTags', CollectionType::class, [
'by_reference' => false,
'entry_type' => TaskTagsFormType::class,
'entry_options' => ['label' => false],
'allow_add' => true,
'allow_delete' => true,
'prototype' => true,
]);
}
public function configureOptions(OptionsResolver $resolver): void
{
$resolver->setDefaults([
'data_class' => Task::class,
'csrf_protection' => false
]);
}
}
FormType "TaskTagsFormType"
class TaskTagsFormType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
->add('task')
->add('tag')
->add('value')
;
}
Controller
#[Route('/tasks/edit/{id}/tags', name: 'app_edit_task')]
public function editasktags(Request $request, EntityManagerInterface $em, TaskTagsRepository $TaskTagsRepo): Response
{
...
// Create an ArrayCollection of the current tags assigned to the task
$task = $this->getTask();
// when displaying the form (method GET), this collection shows correctly the tags already assigned to the task
// when the form is submitted, it immediately becomes the collection sent by the form
$ExistingTaskTags = $TaskTagsRepo->findByTask($task);
$form = $this->createForm(TaskFormType::class, $task);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
// here begins all I have tried ... I was trying to compare the value in the DB and in the form, but because of the repo being overwritten I can't
$task = $form->getData();
$SubmittedTaskTags = $userForm->getTaskTags();
$CalculatedTaskTags = new ArrayCollection();
foreach ($ExistingTaskTags as $ExistingTaskTag) {
foreach ($SubmittedTaskTags as $SubmittedTaskTag) {
if ($ExistingTaskTag->getTag()->getId() !== $SubmittedTaskTag->getTag()->getId()) {
// The existing tag is not the same as submitted, keeping it as it in a new collection
$CalculatedTaskTags->add($ExistingTaskTag);
} else {
// The submitted tag is equal to the one in DB, so adding the submitted one
$SubmittedTaskTag->setTask($task);
$CalculatedTaskTags->add($SubmittedTaskTag);
}
}
}
$em->persist($task);
$em->flush();
}
return $this->render('task/edittasktags.twig.html', [
'form' => $form,
'task' => $this->getTask()
]);
}
My main issue is that I am not able to get the existing data one the form has been submitted, in order to perform a "merge"
I have tried so many things.
One I did not, and I'd like to avoid : sending the existing collection as hidden fields.
I don't like this at all since if the data have been modified in the meantime, we are sending outdated data, which could be a mess in multi tab usage.
Thank you in advance for your help, I understand this topic is not that easy.
NB : the code I sent it not my real code / entity. I've re written according to the Symfony doc case, so there could be some typo here and there, apologize.

Answer 1

Solution found.
I added 'mapped' => false in the FormType.
And I was able to retrieve the form data using
$SubmittedTags = $form->get('TaskTags')->getData();
The repository was not overwritten by the submitted collection.