Check if the language module is enabled. (#835)

Author: fubhy

graphql.services.yml

@@ -81,7 +81,7 @@ services:
   # Reset the current language during operations.
   graphql.operation_subscriber:
     class: Drupal\graphql\EventSubscriber\OperationSubscriber
-    arguments: ['@language_manager', '@string_translation', '@current_user', '@?language_negotiator']
+    arguments: ['@module_handler', '@language_manager', '@string_translation', '@current_user', '@?language_negotiator']
     tags:
       - { name: event_subscriber }
 

src/EventSubscriber/OperationSubscriber.php

@@ -2,28 +2,37 @@
 
 namespace Drupal\graphql\EventSubscriber;
 
+use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\StringTranslation\Translator\TranslatorInterface;
 use Drupal\graphql\Event\OperationEvent;
 use Drupal\graphql\Plugin\LanguageNegotiation\OperationLanguageNegotiation;
-use Drupal\language\ConfigurableLanguageManagerInterface;
 use Drupal\language\LanguageNegotiatorInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
 class OperationSubscriber implements EventSubscriberInterface {
 
   use CurrentLanguageResetTrait;
 
+  /**
+   * The module handler service.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
   /**
    * Constructs a OperationSubscriber object.
    *
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
    * @param \Drupal\Core\Language\LanguageManagerInterface $languageManager
    * @param \Drupal\Core\StringTranslation\Translator\TranslatorInterface $translator
    * @param \Drupal\Core\Session\AccountInterface $currentUser
    * @param \Drupal\language\LanguageNegotiatorInterface $languageNegotiator
    */
-  public function __construct(LanguageManagerInterface $languageManager, TranslatorInterface $translator, AccountInterface $currentUser, LanguageNegotiatorInterface $languageNegotiator = NULL) {
+  public function __construct(ModuleHandlerInterface $moduleHandler, LanguageManagerInterface $languageManager, TranslatorInterface $translator, AccountInterface $currentUser, LanguageNegotiatorInterface $languageNegotiator = NULL) {
+    $this->moduleHandler = $moduleHandler;
     $this->languageManager = $languageManager;
     $this->translator = $translator;
     $this->currentUser = $currentUser;
@@ -37,7 +46,7 @@ public function __construct(LanguageManagerInterface $languageManager, Translato
    *   The kernel event object.
    */
   public function onBeforeOperation(OperationEvent $event) {
-    if (!empty($this->languageNegotiator)) {
+    if ($this->moduleHandler->moduleExists('language') && !empty($this->languageNegotiator)) {
       OperationLanguageNegotiation::setContext($event->getContext());
     }
 
@@ -51,7 +60,7 @@ public function onBeforeOperation(OperationEvent $event) {
    *   The kernel event object.
    */
   public function onAfterOperation(OperationEvent $event) {
-    if (!empty($this->languageNegotiator)) {
+    if ($this->moduleHandler->moduleExists('language') && !empty($this->languageNegotiator)) {
       OperationLanguageNegotiation::setContext($event->getContext());
     }