Issue #3222577 by alexpott, podarok, daffie: ServiceNotFoundException You have requested a non-existent service "language_negotiator" - hook_modules_installed()

core/lib/Drupal/Core/DrupalKernel.php

@@ -515,6 +515,7 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
     }
     $this->container->get('stream_wrapper_manager')->unregister();
     $this->booted = FALSE;
+    $this->configStorage = NULL;
     $this->container = NULL;
     $this->moduleList = NULL;
     $this->moduleData = [];

core/lib/Drupal/Core/Test/FunctionalTestSetupTrait.php

@@ -292,7 +292,11 @@ trait FunctionalTestSetupTrait {
    */
   protected function doInstall() {
     require_once DRUPAL_ROOT . '/core/includes/install.core.inc';
-    install_drupal($this->classLoader, $this->installParameters());
+    $parameters = $this->installParameters();
+    // Simulate a real install which does not start with the any connections set
+    // in \Drupal\Core\Database\Database::$connections.
+    Database::removeConnection('default');
+    install_drupal($this->classLoader, $parameters);
   }
 
   /**

core/tests/Drupal/FunctionalTests/Installer/DrupalFlushAllCachesInInstallerTest.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace Drupal\FunctionalTests\Installer;
+
+use Drupal\Core\Serialization\Yaml;
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests drupal_flush_all_caches() during an install.
+ *
+ * @group Installer
+ */
+class DrupalFlushAllCachesInInstallerTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $profile = 'cache_flush_test';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function prepareEnvironment() {
+    parent::prepareEnvironment();
+    $info = [
+      'type' => 'profile',
+      'core_version_requirement' => '*',
+      'name' => 'Cache flush test',
+      'install' => ['language'],
+    ];
+    // File API functions are not available yet.
+    $path = $this->siteDirectory . '/profiles/cache_flush_test';
+    mkdir($path, 0777, TRUE);
+    file_put_contents("$path/cache_flush_test.info.yml", Yaml::encode($info));
+    $php_code = <<<EOF
+<?php
+function cache_flush_test_install() {
+  // Note it is bad practice to call this method during hook_install() as it
+  // results in an additional expensive container rebuild.
+  drupal_flush_all_caches();
+  // Ensure services are available after calling drupal_flush_all_caches().
+  \Drupal::state()->set('cache_flush_test', \Drupal::hasService('language_negotiator'));
+}
+EOF;
+
+    file_put_contents("$path/cache_flush_test.install", $php_code);
+  }
+
+  /**
+   * Confirms that the installation succeeded.
+   */
+  public function testInstalled() {
+    $this->assertTrue(\Drupal::state()->get('cache_flush_test'));
+  }
+
+}

core/tests/Drupal/FunctionalTests/Installer/InstallerTranslationTest.php

@@ -92,9 +92,9 @@ class InstallerTranslationTest extends InstallerTestBase {
     $this->rebuildContainer();
     /** @var \Drupal\user\Entity\User $account */
     $account = User::load(0);
-    $this->assertEquals('en', $account->language()->getId(), 'Anonymous user is English.');
+    $this->assertEquals('de', $account->language()->getId(), 'Anonymous user is German.');
     $account = User::load(1);
-    $this->assertEquals('en', $account->language()->getId(), 'Administrator user is English.');
+    $this->assertEquals('de', $account->language()->getId(), 'Administrator user is German.');
     $account = $this->drupalCreateUser();
     $this->assertEquals('de', $account->language()->getId(), 'New user is German.');