ConfigExistsConstraintValidator.php

<?php

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

use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

/**
 * Validates that a given config object exists.
 */
class ConfigExistsConstraintValidator extends ConstraintValidator implements ContainerInjectionInterface {
    
    /**
     * The config factory service.
     *
     * @var \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected ConfigFactoryInterface $configFactory;
    
    /**
     * Constructs a ConfigExistsConstraintValidator object.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config factory service.
     */
    public function __construct(ConfigFactoryInterface $config_factory) {
        $this->configFactory = $config_factory;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('config.factory'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function validate(mixed $name, Constraint $constraint) {
        assert($constraint instanceof ConfigExistsConstraint);
        // This constraint may be used to validate nullable (optional) values.
        if ($name === NULL) {
            return;
        }
        if (!in_array($constraint->prefix . $name, $this->configFactory
            ->listAll($constraint->prefix), TRUE)) {
            $this->context
                ->addViolation($constraint->message, [
                '@name' => $constraint->prefix . $name,
            ]);
        }
    }

}