BcConfigSubscriber.php

<?php

namespace Drupal\serialization\EventSubscriber;

use Drupal\Core\Config\ConfigCrudEvent;
use Drupal\Core\Config\ConfigEvents;
use Drupal\Core\DrupalKernelInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Config event subscriber to rebuild the container when BC config is saved.
 */
class BcConfigSubscriber implements EventSubscriberInterface {
    
    /**
     * The Drupal Kernel.
     *
     * @var \Drupal\Core\DrupalKernelInterface
     */
    protected $kernel;
    
    /**
     * BcConfigSubscriber constructor.
     *
     * @param \Drupal\Core\DrupalKernelInterface $kernel
     *   The Drupal Kernel.
     */
    public function __construct(DrupalKernelInterface $kernel) {
        $this->kernel = $kernel;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() {
        $events[ConfigEvents::SAVE][] = 'onConfigSave';
        return $events;
    }
    
    /**
     * Invalidates the service container if serialization BC config gets updated.
     *
     * @param \Drupal\Core\Config\ConfigCrudEvent $event
     */
    public function onConfigSave(ConfigCrudEvent $event) {
        $saved_config = $event->getConfig();
        if ($saved_config->getName() === 'serialization.settings') {
            if ($event->isChanged('bc_primitives_as_strings') || $event->isChanged('bc_timestamp_normalizer_unix')) {
                $this->kernel
                    ->invalidateContainer();
            }
        }
    }

}