MenuTreeHierarchyConstraint.php

<?php

namespace Drupal\menu_link_content\Plugin\Validation\Constraint;

use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Validation\Attribute\Constraint;

/**
 * Validation constraint for changing the menu hierarchy in pending revisions.
 */
class MenuTreeHierarchyConstraint extends CompositeConstraintBase {
    
    /**
     * The default violation message.
     *
     * @var string
     */
    public $message = 'You can only change the hierarchy for the <em>published</em> version of this menu link.';
    
    /**
     * {@inheritdoc}
     */
    public function coversFields() {
        return [
            'parent',
            'weight',
        ];
    }

}