[Form] Applying bug #18935 fix (done only on symfony/form)

[Ghriim]

Q	A
Branch?	3.2
Bug fix?	yes
New feature?	no
BC breaks?	yes (only for the behavior)
Deprecations?	no
Tests pass?	yes
Fixed tickets	symfony/form #11493
License	MIT
Doc PR	see symfony/form@8502f30)

[HeahDude]

This is a duplicate of #18935 which has been reverted.

Sadly we cannot afford this bc break, prepopulating data in a form does not belong to the scope of its validation if it is not submitted.

Btw, calling $form->isValid() without calling $form->isSubmitted() first has been deprecated in 3.2, so this can be more consistant.

[Ghriim]

I've discover this bug fix from this ticket #11493
Is their any work around for PATCH context if the fix on ViolationMapper is finally reverted ?

[HeahDude]

@Ghriim $this->get('validator')->validate($form->getData()) should be enough to avoid persisting wrong data ;), but you'll have to handle errors yourself though.

[xabbuh]

Can you confirm that the changes proposed in #30265 will fix this issue?