Update languages during rendering using approach from #3380219

Update and apply https://www.drupal.org/files/issues/2023-08-09/3380219-1-v1.x.patch Restore previous active and default languages after rendering

Closes #3035977

src/Plugin/search_api/processor/RenderedItem.php

@@ -4,14 +4,18 @@ namespace Drupal\search_api\Plugin\search_api\processor;
 
 use Drupal\Component\Utility\DeprecationHelper;
 use Drupal\Core\Entity\Entity\EntityViewMode;
+use Drupal\Core\Language\LanguageDefault;
+use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\Link;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Session\AccountSwitcherInterface;
 use Drupal\Core\Session\UserSession;
+use Drupal\Core\StringTranslation\TranslationManager;
 use Drupal\Core\Url;
 use Drupal\search_api\Datasource\DatasourceInterface;
 use Drupal\search_api\Item\ItemInterface;
 use Drupal\search_api\LoggerTrait;
+use Drupal\search_api\Plugin\search_api\datasource\ContentEntity;
 use Drupal\search_api\Plugin\search_api\processor\Property\RenderedItemProperty;
 use Drupal\search_api\Processor\ProcessorPluginBase;
 use Drupal\search_api\Utility\ThemeSwitcherInterface;
@@ -59,6 +63,20 @@ class RenderedItem extends ProcessorPluginBase {
    */
   protected $themeSwitcher;
 
+  /**
+   * The language manager.
+   *
+   * @var \Drupal\Core\Language\LanguageManagerInterface
+   */
+  protected $languageManager;
+
+  /**
+   * The language default.
+   *
+   * @var \Drupal\Core\Language\LanguageDefault
+   */
+  protected $languageDefault;
+
   /**
    * {@inheritdoc}
    */
@@ -70,7 +88,8 @@ class RenderedItem extends ProcessorPluginBase {
     $plugin->setRenderer($container->get('renderer'));
     $plugin->setThemeSwitcher($container->get('search_api.theme_switcher'));
     $plugin->setLogger($container->get('logger.channel.search_api'));
-
+    $plugin->setLanguageManager($container->get('language_manager'));
+    $plugin->setLanguageDefault($container->get('language.default'));
     return $plugin;
   }
 
@@ -143,6 +162,32 @@ class RenderedItem extends ProcessorPluginBase {
     return $this;
   }
 
+  /**
+   * Sets the language manager.
+   *
+   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
+   *   The language manager.
+   *
+   * @return $this
+   */
+  protected function setLanguageManager(LanguageManagerInterface $language_manager) {
+    $this->languageManager = $language_manager;
+    return $this;
+  }
+
+  /**
+   * Sets the default language.
+   *
+   * @param \Drupal\Core\Language\LanguageDefault $language_default
+   *   The default language.
+   *
+   * @return $this
+   */
+  protected function setLanguageDefault(LanguageDefault $language_default) {
+    $this->languageDefault = $language_default;
+    return $this;
+  }
+
   // @todo Add a supportsIndex() implementation that checks whether there is
   //   actually any datasource present which supports viewing.
 
@@ -217,6 +262,15 @@ class RenderedItem extends ProcessorPluginBase {
         if ($build) {
           // Add the excerpt to the render array to allow adding it to view modes.
           $build['#search_api_excerpt'] = $item->getExcerpt();
+
+          // Change the active language before rendering so string translations
+          // and field labels are rendered in the correct language.
+          if ($item->getDatasource() instanceof ContentEntity) {
+            $original_default_language = $this->languageDefault->get()->getId();
+            $original_active_language = $this->languageManager->getConfigOverrideLanguage()->getId();
+            $this->changeActiveLanguage($item->getLanguage(), $item->getLanguage());
+          }
+
           $value = (string) DeprecationHelper::backwardsCompatibleCall(
             \Drupal::VERSION, '10.3.0',
             fn () => $this->getRenderer()->renderInIsolation($build),
@@ -225,6 +279,11 @@ class RenderedItem extends ProcessorPluginBase {
           if ($value) {
             $field->addValue($value);
           }
+
+          // Restore the original active language.
+          if ($item->getDatasource() instanceof ContentEntity) {
+            $this->changeActiveLanguage($original_active_language, $original_default_language);
+          }
         }
       }
       catch (\Throwable $e) {
@@ -334,4 +393,41 @@ class RenderedItem extends ProcessorPluginBase {
     return TRUE;
   }
 
+  /**
+   * Changes the active language for translations.
+   *
+   * @param string $langcode
+   *   The langcode.
+   * @param string $default_langcode
+   *   The site default langcode.
+   */
+  protected function changeActiveLanguage($langcode, $default_langcode) {
+    if (!$this->languageManager->isMultilingual()) {
+      return;
+    }
+    $language = $this->languageManager->getLanguage($langcode);
+    $default_language = $this->languageManager->getLanguage($default_langcode);
+    if (!$language || !$default_language) {
+      return;
+    }
+    // The language manager has no method for overriding the default
+    // language, like it does for config overrides. We have to change the
+    // default language service's current language.
+    // @see https://www.drupal.org/project/drupal/issues/3029010
+    $this->languageDefault->set($default_language);
+    $this->languageManager->setConfigOverrideLanguage($language);
+    $this->languageManager->reset();
+
+    // The default string_translation service, TranslationManager, has a
+    // setDefaultLangcode method. However, this method is not present on
+    // either of its interfaces. Therefore we check for the concrete class
+    // here so that any swapped service does not break the application.
+    // @see https://www.drupal.org/project/drupal/issues/3029003
+    $string_translation = $this->getStringTranslation();
+    if ($string_translation instanceof TranslationManager) {
+      $string_translation->setDefaultLangcode($language->getId());
+      $string_translation->reset();
+    }
+  }
+
 }