Issue #2240459 by Gábor Hojtsy, penyaskito | LoMo: Fixed Applying default...

Issue #2240459 by Gábor Hojtsy, penyaskito | LoMo: Fixed Applying default language fallback rules to interface translation has impressively bad results.

core/lib/Drupal/Core/Entity/EntityManager.php

@@ -773,8 +773,8 @@ public function getTranslationFromContext(EntityInterface $entity, $langcode = N
       // Retrieve language fallback candidates to perform the entity language
       // negotiation.
       $context['data'] = $entity;
-      $context += array('operation' => 'entity_view');
-      $candidates = $this->languageManager->getFallbackCandidates($langcode, $context);
+      $context += array('operation' => 'entity_view', 'langcode' => $langcode);
+      $candidates = $this->languageManager->getFallbackCandidates($context);
 
       // Ensure the default language has the proper language code.
       $default_language = $entity->getUntranslated()->language();

core/lib/Drupal/Core/Language/LanguageManager.php

@@ -194,7 +194,7 @@ public function isLanguageLocked($langcode) {
   /**
    * {@inheritdoc}
    */
-  public function getFallbackCandidates($langcode = NULL, array $context = array()) {
+  public function getFallbackCandidates(array $context = array()) {
     return array(LanguageInterface::LANGCODE_DEFAULT);
   }
 

core/lib/Drupal/Core/Language/LanguageManagerInterface.php

@@ -132,22 +132,27 @@ public function isLanguageLocked($langcode);
   /**
    * Returns the language fallback candidates for a given context.
    *
-   * @param string $langcode
-   *   (optional) The language of the current context. Defaults to NULL.
    * @param array $context
    *   (optional) An associative array of data that can be useful to determine
    *   the fallback sequence. The following keys are used in core:
-   *   - langcode: The desired language.
+   *   - langcode: Language code of the desired language.
    *   - operation: The name of the operation indicating the context where
-   *     language fallback is being applied, e.g. 'entity_view'.
-   *   - data: An arbitrary data structure that makes sense in the provided
-   *     context, e.g. an entity.
+   *     language fallback is being applied. The following operations are
+   *     defined in core, but more may be defined in contributed modules:
+   *       - entity_view: Invoked when an entity is about to be displayed.
+   *         The data key contains the loaded entity.
+   *       - views_query: Invoked when a field based views query is performed.
+   *         The data key contains a reference to the field object.
+   *       - locale_lookup: Invoked when a string translation was not found.
+   *         The data key contains the source string.
+   *   - data: A data structure that makes sense in the provided
+   *     context, see above.
    *
    * @return array
    *   An array of language codes sorted by priority: first values should be
    *   tried first.
    */
-  public function getFallbackCandidates($langcode = NULL, array $context = array());
+  public function getFallbackCandidates(array $context = array());
 
   /**
    * Returns the language switch links for the given language type.

core/modules/field/src/Plugin/views/field/Field.php

@@ -305,7 +305,7 @@ public function query($use_groupby = FALSE) {
           $this->view->display_handler->options['field_langcode']
         );
         $placeholder = $this->placeholder();
-        $langcode_fallback_candidates = $this->languageManager->getFallbackCandidates($langcode, array('operation' => 'views_query', 'data' => $this));
+        $langcode_fallback_candidates = $this->languageManager->getFallbackCandidates(array('langcode' => $langcode, 'operation' => 'views_query', 'data' => $this));
         $this->query->addWhereExpression(0, "$column IN($placeholder) OR $column IS NULL", array($placeholder => $langcode_fallback_candidates));
       }
     }

core/modules/language/src/ConfigurableLanguageManager.php

@@ -326,17 +326,24 @@ public function updateLockedLanguageWeights() {
   /**
    * {@inheritdoc}
    */
-  public function getFallbackCandidates($langcode = NULL, array $context = array()) {
+  public function getFallbackCandidates(array $context = array()) {
     if ($this->isMultilingual()) {
-      // Get languages ordered by weight, add BaseLanguageInterface::LANGCODE_NOT_SPECIFIED
-      // at the end.
-      $candidates = array_keys($this->getLanguages());
-      $candidates[] = BaseLanguageInterface::LANGCODE_NOT_SPECIFIED;
-      $candidates = array_combine($candidates, $candidates);
-
-      // The first candidate should always be the desired language if specified.
-      if (!empty($langcode)) {
-        $candidates = array($langcode => $langcode) + $candidates;
+      $candidates = array();
+      if (empty($context['operation']) || $context['operation'] != 'locale_lookup') {
+        // If the fallback context is not locale_lookup, initialize the
+        // candidates with languages ordered by weight and add
+        // BaseLanguageInterface::LANGCODE_NOT_SPECIFIED at the end. Interface
+        // translation fallback should only be based on explicit configuration
+        // gathered via the alter hooks below.
+        $candidates = array_keys($this->getLanguages());
+        $candidates[] = BaseLanguageInterface::LANGCODE_NOT_SPECIFIED;
+        $candidates = array_combine($candidates, $candidates);
+
+        // The first candidate should always be the desired language if
+        // specified.
+        if (!empty($context['langcode'])) {
+          $candidates = array($context['langcode'] => $context['langcode']) + $candidates;
+        }
       }
 
       // Let other modules hook in and add/change candidates.
@@ -349,7 +356,7 @@ public function getFallbackCandidates($langcode = NULL, array $context = array()
       $this->moduleHandler->alter($types, $candidates, $context);
     }
     else {
-      $candidates = parent::getFallbackCandidates($langcode, $context);
+      $candidates = parent::getFallbackCandidates($context);
     }
 
     return $candidates;

core/modules/language/src/Tests/LanguageFallbackTest.php

@@ -56,7 +56,7 @@ public function testCandidates() {
     $this->state->set('language_test.fallback_operation_alter.candidates', TRUE);
     $expected[] = LanguageInterface::LANGCODE_NOT_SPECIFIED;
     $expected[] = LanguageInterface::LANGCODE_NOT_APPLICABLE;
-    $candidates = $this->languageManager->getFallbackCandidates(NULL, array('operation' => 'test'));
+    $candidates = $this->languageManager->getFallbackCandidates(array('operation' => 'test'));
     $this->assertEqual(array_values($candidates), $expected, 'Language fallback candidates are alterable for specific operations.');
 
     // Check that when the site is monolingual no language fallback is applied.

core/modules/locale/src/LocaleLookup.php

@@ -127,7 +127,7 @@ protected function resolveCacheMiss($offset) {
     // If there is no translation available for the current language then use
     // language fallback to try other translations.
     if ($value === TRUE) {
-      $fallbacks = $this->languageManager->getFallbackCandidates($this->langcode, array('operation' => 'locale_lookup', 'data' => $offset));
+      $fallbacks = $this->languageManager->getFallbackCandidates(array('langcode' => $this->langcode, 'operation' => 'locale_lookup', 'data' => $offset));
       if (!empty($fallbacks)) {
         foreach ($fallbacks as $langcode) {
           $translation = $this->stringStorage->findTranslation(array(

core/modules/locale/src/Tests/LocaleLocaleLookupTest.php

@@ -11,7 +11,7 @@
 use Drupal\simpletest\WebTestBase;
 
 /**
- * Tests that LocaleLookup does not cause circular references.
+ * Tests LocaleLookup.
  *
  * @group locale
  */
@@ -22,12 +22,14 @@ class LocaleLocaleLookupTest extends WebTestBase {
    *
    * @var array
    */
-  public static $modules = array('locale');
+  public static $modules = array('locale', 'locale_test');
 
   /**
-   * Tests hasTranslation().
+   * {@inheritdoc}
    */
-  public function testCircularDependency() {
+  public function setUp() {
+    parent::setUp();
+
     // Change the language default object to different values.
     $new_language_default = new Language(array(
       'id' => 'fr',
@@ -39,9 +41,29 @@ public function testCircularDependency() {
     ));
     language_save($new_language_default);
     $this->drupalLogin($this->root_user);
+  }
+
+  /**
+   * Tests that there are no circular dependencies.
+   */
+  public function testCircularDependency() {
     // Ensure that we can enable early_translation_test on a non-english site.
     $this->drupalPostForm('admin/modules', array('modules[Testing][early_translation_test][enable]' => TRUE), t('Save configuration'));
     $this->assertResponse(200);
   }
 
+  /**
+   * Test language fallback defaults.
+   */
+  public function testLanguageFallbackDefaults() {
+    $this->drupalGet('');
+    // Ensure state of fallback languages persisted by
+    // locale_test_language_fallback_candidates_locale_lookup_alter() is empty.
+    $this->assertEqual(\Drupal::state()->get('locale.test_language_fallback_candidates_locale_lookup_alter_candidates'), array());
+    // Make sure there is enough information provided for alter hooks.
+    $context = \Drupal::state()->get('locale.test_language_fallback_candidates_locale_lookup_alter_context');
+    $this->assertEqual($context['langcode'], 'fr');
+    $this->assertEqual($context['operation'], 'locale_lookup');
+  }
+
 }

core/modules/locale/tests/modules/locale_test/locale_test.module

@@ -129,3 +129,11 @@ function locale_test_locale_translation_projects_alter(&$projects) {
     );
   }
 }
+
+/**
+ * Implements hook_language_fallback_candidates_OPERATION_alter().
+ */
+function locale_test_language_fallback_candidates_locale_lookup_alter(array &$candidates, array $context) {
+  \Drupal::state()->set('locale.test_language_fallback_candidates_locale_lookup_alter_candidates', $candidates);
+  \Drupal::state()->set('locale.test_language_fallback_candidates_locale_lookup_alter_context', $context);
+}

core/modules/locale/tests/src/LocaleLookupTest.php

@@ -158,8 +158,8 @@ public function testResolveCacheMissWithFallback($langcode, $string, $context, $
 
     $this->languageManager->expects($this->any())
       ->method('getFallbackCandidates')
-      ->will($this->returnCallback(function ($langcode) {
-        switch ($langcode) {
+      ->will($this->returnCallback(function (array $context = array()) {
+        switch ($context['langcode']) {
           case 'pl':
             return array('cs', 'en');
 

core/tests/Drupal/Tests/Core/Entity/EntityManagerTest.php

@@ -925,10 +925,10 @@ public function testGetTranslationFromContext() {
 
     $this->languageManager->expects($this->exactly(2))
       ->method('getFallbackCandidates')
-      ->will($this->returnCallback(function ($langcode = NULL, array $context = array()) {
+      ->will($this->returnCallback(function (array $context = array()) {
         $candidates = array();
-        if ($langcode) {
-          $candidates[$langcode] = $langcode;
+        if (!empty($context['langcode'])) {
+          $candidates[$context['langcode']] = $context['langcode'];
         }
         return $candidates;
       }));