@xabbuh awesome! I confirmed it works as would validation groups work for every other constraint, i.e. in validation.xml you add groups to Valid and now pass the validation_groups option when creating the form. Valid will only be applied if any of the groups in validation_groups equals those specified in validation.xml.

However, I do think there is one super useful use case not covered. Consider a Profile object having profilePicture and coverPhoto properties - both of type Image, which internally has a file property of type File. Let's say we have different maximum file sizes for both of them, so we add 2 File constraints to the Image object. And both properties should be valid at all times for Profile.

<class name="Profile">
  <property name="profilePicture">
    <constraint name="Valid" />
  </property>
  <property name="coverPhoto">
    <constraint name="Valid" />
  </property>
</class>

<class name="Image">
  <property name="file">
    <constraint name="File">
      <option name="maxSize">100k</option>
      <option name="groups">
        <value>profile-picture</value>
      </option>
    </constraint>
    <constraint name="File">
      <option name="maxSize">1000k</option>
      <option name="groups">
        <value>cover-photo</value>
      </option>
    </constraint>
  </property>
</class>

In ProfileType we'd have something like this probably.

$builder->add('profilePicture', ImageType::class, ['validation_groups' => ['profile-picture']]);
$builder->add('coverPhoto', ImageType::class, ['validation_groups' => ['cover-photo']);

But try as you might, it seems to me that validation for these File objects does not kick in.

$form = $factory->create(ProfileType::class);
$form->handleRequest($request);
$form->isValid(); // returns true for files larger than what was specified

Of course this is a bit nonsensical example, but I tried to simplify as much as possible. In one of my projects we for example have Document objects which wrap all files and in one of the entities one property can contain only XML files and the other one can accept a different whitelist of types.

@kgilden This seems logical to me as the root form itself is validated in the Default group. Configuration validation_groups for the root form to be, for example, ['Default', 'profile-picture', 'cover-photo'] should do the trick.

@xabbuh ahh yes, sorry for the confusion. I should note that this patch is still required to make my example above work. The same groups must also be added to Valid constraints and then it works as expected.

@kgilden You are right. But IMO this behaviour is straight-forward with how validation groups in Symfony work in general. Do you disagree with that?

@xabbuh it's straight-forward if for example the File constraint is applied to two distinct properties on the root object, i.e.

<class name="Profile">
  <property name="profilePicture">
    <constraint name="File">
        <!-- distinct options -->
    </constraint>
  </property>
  <property name="coverPhoto">
    <constraint name="File">
        <!-- distinct options -->
    </constraint>
  </property>
</class>

What I think is currently not possible is when you want to validate the same objects deeper. After this PR it's possible to do as follows.

<class name="Profile">
  <property name="profilePicture">
    <constraint name="Valid">
      <option name="groups">
        <value>profile-picture</value>
      </option>
    </constraint>
  </property>
  <property name="coverPhoto">
    <constraint name="Valid">
      <option name="groups">
        <value>cover-photo</value>
      </option>
    </constraint>
  </property>
</class>

<class name="Image">
  <property name="file">
    <constraint name="File">
      <option name="maxSize">100k</option>
      <option name="groups">
        <value>profile-picture</value>
      </option>
    </constraint>
    <constraint name="File">
      <option name="maxSize">1000k</option>
      <option name="groups">
        <value>cover-photo</value>
      </option>
    </constraint>
  </property>
</class>

class ProfileType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('profilePicture', ImageType::class);
        $builder->add('coverPhoto', ImageType::class);
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(['validation_groups' => ['Default', 'cover-photo', 'profile-picture']]);
    }
}

Correct me if I'm wrong, but I don't think there was a way to do it prior to this PR.

Indeed, that's not possible right now.

+1 for this feature. The use case described by kgilden happens regularly for me (deep cascade validation groups)

@xabbuh Can you add a note in the CHANGELOG before I can merge?

@fabpot done, but are we sure that this is the right way to implement it?

ping @symfony/deciders

Thank you @xabbuh.

Hi,
What if value is null? i need @Assert\Valid only after and when @Assert\NotNull is valid, currently i get 500 error because of that empty value

@Atiragram : This is already supposed to be fixed in #25297, available since 3.4.1. If you still encounter an issue, please open a new issue with a reproducer or a failing test case. Thanks!