CssSelectorConstraint.php

<?php

declare (strict_types=1);
namespace Drupal\Core\Theme\Plugin\Validation\Constraint;

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

/**
 * Checks if the string is a correct CSS selector.
 */
class CssSelectorConstraint extends SymfonyConstraint {
  public function __construct(public string $message = 'The CSS selector @scope is invalid.', ?array $groups = NULL, mixed $payload = NULL) {
    parent::__construct(groups: $groups, payload: $payload);
  }

}