ConfigSubscriber::onConfigSave

public ConfigSubscriber::onConfigSave(ConfigCrudEvent $event)

public function onConfigSave(ConfigCrudEvent $event) {
  $saved_config = $event->getConfig();
  if ($saved_config->getName() == 'system.site' && $event->isChanged('default_langcode')) {
    $new_default_langcode = $saved_config->get('default_langcode');
    $default_language = $this->configFactory->get('language.entity.' . $new_default_langcode);
    // During an import the language might not exist yet.
    if (!$default_language->isNew()) {
      $this->languageDefault->set(new Language($default_language->get()));
      $this->languageManager->reset();

      // Directly update language negotiation settings instead of calling
      // language_negotiation_url_prefixes_update() to ensure that the code
      // obeys the hook_update_N() restrictions.
      $negotiation_config = $this->configFactory->getEditable('language.negotiation');
      $negotiation_changed = FALSE;
      $url_prefixes = $negotiation_config->get('url.prefixes');
      $old_default_langcode = $saved_config->getOriginal('default_langcode');
      if (empty($url_prefixes[$old_default_langcode])) {
        $negotiation_config->set('url.prefixes.' . $old_default_langcode, $old_default_langcode);
        $negotiation_changed = TRUE;
      }
      if (empty($url_prefixes[$new_default_langcode])) {
        $negotiation_config->set('url.prefixes.' . $new_default_langcode, '');
        $negotiation_changed = TRUE;
      }
      if ($negotiation_changed) {
        $negotiation_config->save(TRUE);
      }
    }
    // Trigger a container rebuild on the next request by invalidating it.
    ConfigurableLanguageManager::rebuildServices();
  }
  elseif ($saved_config->getName() == 'language.types' && $event->isChanged('negotiation')) {
    // If the negotiation configuration changed the language negotiator and
    // the language path processor have to be reset so that they regenerate
    // the method instances and also sort them accordingly to the new config.
    $this->languageNegotiator->reset();
    if (isset($this->pathProcessorLanguage)) {
      $this->pathProcessorLanguage->reset();
    }
  }
}