Allow PhutilTranslator::translate() to return defaults

Summary: Allow PhutilTranslator::translate() to return defaults

Test Plan: Just check some strings returned correctly.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, Zolli, epriestley

Projects: #localization

Maniphest Tasks: T6845

Differential Revision: https://secure.phabricator.com/D11121

src/applications/base/controller/PhabricatorController.php

@@ -102,7 +102,7 @@ abstract class PhabricatorController extends AphrontController {
       $translation = newv($translation, array());
       PhutilTranslator::getInstance()
         ->setLanguage($translation->getLanguage())
-        ->addTranslations($translation->getTranslations());
+        ->addTranslations($translation->getCleanTranslations());
     }
 
     $preferences = $user->loadPreferences();

src/infrastructure/env/PhabricatorEnv.php

@@ -117,7 +117,7 @@ final class PhabricatorEnv {
     $translation = PhabricatorEnv::newObjectFromConfig('translation.provider');
     PhutilTranslator::getInstance()
       ->setLanguage($translation->getLanguage())
-      ->addTranslations($translation->getTranslations());
+      ->addTranslations($translation->getCleanTranslations());
   }
 
   private static function buildConfigurationSourceStack() {

src/infrastructure/internationalization/translation/PhabricatorTranslation.php

@@ -6,4 +6,32 @@ abstract class PhabricatorTranslation {
   abstract public function getName();
   abstract public function getTranslations();
 
+
+  /**
+   * Return the cleaned translation array.
+   *
+   * @return dict<string, wild> Translation map with empty translations removed.
+   */
+  public function getCleanTranslations() {
+    return $this->clean($this->getTranslations());
+  }
+
+
+  /**
+   * Removes NULL-valued translation keys from the translation map, to prevent
+   * echoing out empty strings.
+   *
+   * @param dict<string, wild> Translation map, with empty translations.
+   * @return dict<string, wild> Map with empty translations removed.
+   */
+  protected function clean(array $translation_array) {
+    foreach ($translation_array as $key => $translation_string) {
+      if ($translation_string === null) {
+        unset($translation_array[$key]);
+      }
+    }
+
+    return $translation_array;
+  }
+
 }