Issue #1914070 by Sutharsan, pp, YesCT: Improve version fallback for install language.

core/lib/Drupal/Core/StringTranslation/Translator/FileTranslation.php

@@ -59,6 +59,10 @@ protected function loadLanguage($langcode) {
   /**
    * Finds installer translations either for a specific or all languages.
    *
+   * Filenames must match the pattern:
+   *  - 'drupal-[number].*.[langcode].po
+   *  - 'drupal-[number].*.*.po
+   *
    * @param string $langcode
    *   (optional) The language code corresponding to the language for which we
    *   want to find translation files. If omitted, information on all available
@@ -71,7 +75,7 @@ protected function loadLanguage($langcode) {
    * @see file_scan_directory()
    */
   public function findTranslationFiles($langcode = NULL) {
-    $files = file_scan_directory($this->directory, '!drupal-\d+\.\d+\.' . (!empty($langcode) ? preg_quote($langcode, '!') : '[^\.]+') . '\.po$!', array('recurse' => FALSE));
+    $files = file_scan_directory($this->directory, '!drupal-\d+\.[^\.]+\.' . (!empty($langcode) ? preg_quote($langcode, '!') : '[^\.]+') . '\.po$!', array('recurse' => FALSE));
     return $files;
   }
 

core/modules/system/lib/Drupal/system/Tests/Installer/InstallerTranslationVersionUnitTest.php

+<?php
+
+/**
+ * @file
+ * Contains Drupal\system\Tests\Installer\InstallerTranslationVersionUnitTest.
+ */
+
+namespace Drupal\system\Tests\Installer;
+
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests translation release version fallback.
+ */
+class InstallerTranslationVersionUnitTest extends DrupalUnitTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Installer translation version fallback',
+      'description' => 'Tests the translation version fallback used during site installation to determine available translation files.',
+      'group' => 'Installer',
+    );
+  }
+
+  protected function setUp() {
+    parent::setUp();
+    require_once DRUPAL_ROOT . '/core/includes/install.core.inc';
+  }
+
+  /**
+   * Asserts version fallback results of install_get_localization_release().
+   *
+   * @param $version
+   *   Version string for which to determine version fallbacks.
+   * @param $fallback
+   *   Array of fallback versions ordered for most to least significant.
+   * @param string $message
+   *   (optional) A message to display with the assertion.
+   * @param string $group
+   *   (optional) The group this message is in.
+   *
+   * @return bool
+   *   TRUE if the assertion succeeded, FALSE otherwise.
+   */
+  protected function assertVersionFallback($version, $fallback, $message = '', $group = 'Other') {
+    $equal = TRUE;
+    $results = install_get_localization_release($version);
+    // Check the calculated results with the required results.
+    // The $results is an array of arrays, each containing:
+    //   'version': A release version (e.g. 8.0)
+    //   'core'   : The matching core version (e.g. 8.x)
+    if (count($fallback) == count($results)) {
+      foreach($results as $key => $result) {
+        $equal &= $result['version'] == $fallback[$key];
+        list($major_release) = explode('.', $fallback[$key]);
+        $equal &= $result['core'] == $major_release . '.x';
+      }
+    }
+    else {
+      $equal = FALSE;
+    }
+    $message = $message ? $message : t('Version fallback for @version.', array('@version' => $version));
+    return $this->assert((bool) $equal, $message, $group);
+  }
+
+  /**
+   * Tests version fallback of install_get_localization_release().
+   */
+  public function testVersionFallback() {
+    $version = '8.0';
+    $fallback = array('8.0', '8.0-rc1', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.1';
+    $fallback = array('8.1', '8.0', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.12';
+    $fallback = array('8.12', '8.11', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-dev';
+    $fallback = array('8.0-rc1', '8.0-beta1', '8.0-alpha2', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.9-dev';
+    $fallback = array('8.8', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-alpha3';
+    $fallback = array('8.0-alpha3', '8.0-alpha2', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-alpha1';
+    $fallback = array('8.0-alpha1', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-beta2';
+    $fallback = array('8.0-beta2', '8.0-beta1', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-beta1';
+    $fallback = array('8.0-beta1', '8.0-alpha2', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-rc8';
+    $fallback = array('8.0-rc8', '8.0-rc7', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-rc1';
+    $fallback = array('8.0-rc1', '8.0-beta1', '7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '8.0-foo2';
+    $fallback = array('7.0');
+    $this->assertVersionFallback($version, $fallback);
+
+    $version = '99.2';
+    $fallback = array('99.2', '99.1', '98.0');
+    $this->assertVersionFallback($version, $fallback);
+  }
+}