ModerationStateConstraint.php

<?php

namespace Drupal\content_moderation\Plugin\Validation\Constraint;

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Validation\Attribute\Constraint;
use Symfony\Component\Validator\Constraint as SymfonyConstraint;

/**
 * Verifies that nodes have a valid moderation state.
 */
class ModerationStateConstraint extends SymfonyConstraint {
    public $message = 'Invalid state transition from %from to %to';
    public $invalidStateMessage = 'State %state does not exist on %workflow workflow';
    public $invalidTransitionAccess = 'You do not have access to transition from %original_state to %new_state';

}