Constraint on paragraph field not working

Question

Here is a very simple code:

1-My constraint plugin (MyConstraint.php)

/**
 * @Constraint(
 *   id = "MyConstraint",
 *   label = @Translation("Never Validated", context = "Validation"),
 *   type = "string"
 * )
 */
class MyConstraint extends Constraint {
  public $message = "error %value";
}

2-My constraint validator (MyConstraintValidator.php) [=>addViolation in all cases]

class MyConstraintValidator extends ConstraintValidator {

  public function validate($items, Constraint $constraint) {
    dpm("I am displayed");
    $this->context->addViolation($constraint->message, [
              '%value' => 10
            ]);
    return;
}

3-My constraint added to my bundle

function mymodule_entity_bundle_field_info_alter(&$fields, EntityTypeInterface $entity_type, $bundle)
{
    if($bundle=='my_bundle'){
      $fields['my_paragraph_field']->addConstraint('MyConstraint', []);
    }
}

Result:

1-The dpm message 'I am displayed' is displayed

2-The entity is saved without any validation error

Notes:

-I have other constraints which are working well, If I test one of them (on my_bundle), the violation of this working constraint will be displayed but not the one with the code detailled here.

-The problematic constraint is added to a paragraph field... I suspect the problem is coming from there

-Nothing in the error logs.

I am looking for a hint to where to look.

Answer 1

On your addConstraint() your second parameter is an empty array - if you do not want to add any options leave that empty or use NULL

Answer 2

Ok, I found the solution...

It was a widget problem!! As I used a custom widget for this paragraph field, I didn't realize that the widget was also handling part of the violation process inside the function flagErrors which was badly overroded.

Sorry for this

Answer 3

You need to add

namespace Drupal\my_module\Plugin\Validation\Constraint;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;


/**
 * Validates the MyConstraint .
 */
class MyConstraintValidator extends ConstraintValidator {


  /**
   * {@inheritdoc}
   */
  public function validate($items, Constraint $constraint) {

    if (!$item = $items->first()) {
      return;
    }

    $field_name = $items->getFieldDefinition()->getName();

    /** @var \Drupal\Core\Entity\EntityInterface $entity */
    $entity = $items->getEntity();

    if ($entity->hasField('my_paragraph_field')) {

      $value = $entity->my_paragraph_field->value;


      // Check if the value matches or not.
      if ($value != 10) {

        $this->context->addViolation($constraint->message, [
          '%value' => 10
        ]);
      }

    }

  }

}

For reference : Adding Constraint to entity referenced Paragraph field