Issue #2182439 by tim.plunkett: Provide a \Drupal::hasService() method.

core/includes/bootstrap.inc

@@ -709,7 +709,7 @@ function drupal_get_filename($type, $name, $filename = NULL) {
     // Verify that we have an keyvalue service before using it. This is required
     // because this function is called during installation.
     // @todo Inject database connection into KeyValueStore\DatabaseStorage.
-    if (($container = \Drupal::getContainer()) && $container->has('keyvalue') && function_exists('db_query')) {
+    if (\Drupal::hasService('keyvalue') && function_exists('db_query')) {
       if ($type == 'module') {
         if (empty($files[$type])) {
           $files[$type] = \Drupal::moduleHandler()->getModuleList();

core/includes/install.inc

@@ -613,7 +613,7 @@ function drupal_install_system($install_state) {
   // Create tables.
   drupal_install_schema('system');
 
-  if (!\Drupal::getContainer()->has('kernel')) {
+  if (!\Drupal::hasService('kernel')) {
     // Immediately boot a kernel to have real services ready. If there's already
     // an initialized request object in the pre-kernel container, persist it in
     // the post-kernel container.

core/lib/Drupal.php

@@ -136,6 +136,19 @@ public static function service($id) {
     return static::$container->get($id);
   }
 
+  /**
+   * Indicates if a service is defined in the container.
+   *
+   * @param string $id
+   *   The ID of the service to check.
+   *
+   * @return bool
+   *   TRUE if the specified service exists, FALSE otherwise.
+   */
+  public static function hasService($id) {
+    return static::$container && static::$container->has($id);
+  }
+
   /**
    * Retrieves the currently active request object.
    *

core/lib/Drupal/Core/Form/FormBuilder.php

@@ -1810,7 +1810,7 @@ protected function drupalStaticReset($name = NULL) {
    */
   protected function currentUser() {
     if (!$this->currentUser) {
-      if (\Drupal::getContainer()->has('current_user')) {
+      if (\Drupal::hasService('current_user')) {
         $this->currentUser = \Drupal::currentUser();
       }
       else {

core/modules/system/lib/Drupal/system/Tests/Bootstrap/GetFilenameUnitTest.php

@@ -33,7 +33,7 @@ function testDrupalGetFilename() {
 
     // Assert that the test is meaningful by making sure the keyvalue service
     // does not exist.
-    $this->assertFalse(\Drupal::getContainer()->has('keyvalue'), 'The container has no keyvalue service.');
+    $this->assertFalse(\Drupal::hasService('keyvalue'), 'The container has no keyvalue service.');
     // Retrieving the location of a module.
     $this->assertIdentical(drupal_get_filename('module', 'xmlrpc'), 'core/modules/xmlrpc/xmlrpc.module', 'Retrieve module location.');
 

core/modules/system/lib/Drupal/system/Tests/ServiceProvider/ServiceProviderTest.php

@@ -33,9 +33,8 @@ public static function getInfo() {
    * Tests that services provided by module service providers get registered to the DIC.
    */
   function testServiceProviderRegistration() {
-    $container = \Drupal::getContainer();
-    $this->assertTrue($container->getDefinition('file.usage')->getClass() == 'Drupal\\service_provider_test\\TestFileUsage', 'Class has been changed');
-    $this->assertTrue($container->has('service_provider_test_class'), 'The service_provider_test_class service has been registered to the DIC');
+    $this->assertTrue(\Drupal::getContainer()->getDefinition('file.usage')->getClass() == 'Drupal\\service_provider_test\\TestFileUsage', 'Class has been changed');
+    $this->assertTrue(\Drupal::hasService('service_provider_test_class'), 'The service_provider_test_class service has been registered to the DIC');
     // The event subscriber method in the test class calls drupal_set_message with
     // a message saying it has fired. This will fire on every page request so it
     // should show up on the front page.
@@ -49,11 +48,11 @@ function testServiceProviderRegistration() {
   function testServiceProviderRegistrationDynamic() {
     // Uninstall the module and ensure the service provider's service is not registered.
     \Drupal::moduleHandler()->uninstall(array('service_provider_test'));
-    $this->assertFalse(\Drupal::getContainer()->has('service_provider_test_class'), 'The service_provider_test_class service does not exist in the DIC.');
+    $this->assertFalse(\Drupal::hasService('service_provider_test_class'), 'The service_provider_test_class service does not exist in the DIC.');
 
     // Install the module and ensure the service provider's service is registered.
     \Drupal::moduleHandler()->install(array('service_provider_test'));
-    $this->assertTrue(\Drupal::getContainer()->has('service_provider_test_class'), 'The service_provider_test_class service exists in the DIC.');
+    $this->assertTrue(\Drupal::hasService('service_provider_test_class'), 'The service_provider_test_class service exists in the DIC.');
   }
 
 }