[LiveComponent][Form] How to use constraints on the Entity's relationships?

[Growiel]

Hi there,

I'm transforming one of my forms to a LiveComponent but I am faced with an issue:

My form is handling a Payment entity, this entity has a Lease relationship:

#[ORM\ManyToOne(targetEntity: Lease::class, inversedBy: 'payments')]
#[ORM\JoinColumn(nullable: false)]
private Lease $lease;

I want to make sure that when the user adds a new payment, they do not go over the rent for the month, so I have this constraint in my amountPaid field:

/** @var Payment $payment */
$payment = $options['data'];

...
->add('amountPaid', NumberType::class, [
                'scale' => 2,
                'html5' => true,
                'label' => 'Amount Paid',
                'attr' => ['step' => '0.01', 'class' => 'form-control'],
                'constraints' => [
                    new GreaterThanOrEqual(0),
                    new LessThanOrEqual($payment->getLease()->getRemainingAmountToPayForCurrentMonth()),
                ]
            ])
... 

This works as expected in my standalone regular form in my controller.

It, however, fails completely with LiveComponent:

From what I was able to trace, the issue is that when the form is updated on the frontend, my original Payment entity with all of its relationship is discarded and a partial of it is created instead.

This is the first time instantiateForm() is called, with the Payment i supplied from the template. No issues here.

This is the second time instantiateForm() is called from ComponentWithFormTrait::submitForm() (line 162), the lease is uninitalized. In fact, every field except the one I just modified (for "automatic validation") is unintialized.

I believe this happens because when the data changes on the frontend, my Payment object in my form is changed to one that only has the data available in form hydrated in it, rather than being my original object updated with the form data. This is somewhat mentioned here but with no solution: https://symfony.com/bundles/ux-live-component/current/index.html#dynamically-updating-the-form-in-a-liveaction

I'm not sure what I can do here, except remove my constraint but I'd like to keep it. Is there a way for make LiveComponent retrieve my real payment and update it with $this->formValues when it re-renders?
Like a normal controller with a form would do: get the payment from id in the URL (or something else), then hydrate it with the new values, then validate it.

I tried adding an hidden EntityType with my lease, to try and force LiveComponent to re-populate it, but that did not work because the payment is not fetched through Doctrine and the relationship cannot be lazy loaded.

I hope I make sense and would appreciate any help I can get on this.

Thanks!

[Growiel]

Ok looks like once again I missed something in the doc: https://symfony.com/bundles/ux-live-component/current/index.html#liveprop-for-entities-more-complex-data

My entity is unpersisted at this point, I set the relation by hand in the controller:

$payment = new Payment();
$payment->setLease($lease);
$payment->setPaymentMethod(PaymentMethod::ONLINE_PAYMENT);
$payment->setPaymentDate(CarbonImmutable::now());
$payment->setAmountPaid($lease->getRemainingAmountToPayForCurrentMonth());
$payment->setStatus(PaymentStatus::PAID);

But since LiveComponent will never actually send the data of my payment as-is with the AJAX call, all the fields that are not in the form are lost, and even if they are not (adding an EntityType, they are set too late for the constraints to be set directly in buildForm().

I have to go but I guess I have to keep the EntityType AND use FormEvents to add my constraints AFTER the form has been re-hydrated (POST_SET_DATA most likely).

Another workaround could be to redo my controller logic in the LiveComponent: pass my Lease / leaseId in the component and in instantiateForm, set all my default data again.

Will report back, still open to suggestions in the meantime.

Thanks.

[Growiel]

The FormEvents route did not work, since even with the addition of the EntityType, my Payment being unpersisted is never properly re-created before the form is created.

What I ended up doing is passing my leaseId as a LiveProp, and recreating my unpersisted object like I used to do in the controller.

Not sure if it's the best, but it seems to do the job.