InputBag.php

<?php

namespace Drupal\Core\Http;

use Symfony\Component\HttpFoundation\ParameterBag;

/**
 * Forward compatibility class for Symfony 5.
 *
 * @internal only used as a bridge from Symfony 4 to Symfony 5, will be removed
 *   in drupal:10.0.0.
 */
final class InputBag extends ParameterBag {
    
    /**
     * Returns the parameters.
     *
     * @param string|null $key
     *   The name of the parameter to return or null to get them all.
     *
     * @return array
     *   An array of parameters.
     */
    public function all(string $key = NULL) : array {
        if ($key === NULL) {
            return $this->parameters;
        }
        $value = $this->parameters[$key] ?? [];
        if (!is_array($value)) {
            throw new \UnexpectedValueException(sprintf('Unexpected value for parameter "%s": expecting "array", got "%s".', $key, get_debug_type($value)));
        }
        return $value;
    }

}