updated core to 8.6.1 via composer

core/modules/action/src/ActionFormBase.php

@@ -132,7 +132,7 @@ abstract class ActionFormBase extends EntityForm {
    */
   public function save(array $form, FormStateInterface $form_state) {
     $this->entity->save();
-    drupal_set_message($this->t('The action has been successfully saved.'));
+    $this->messenger()->addStatus($this->t('The action has been successfully saved.'));
 
     $form_state->setRedirect('entity.action.collection');
   }

core/modules/action/src/Form/ActionAdminManageForm.php

@@ -72,7 +72,7 @@ class ActionAdminManageForm extends FormBase {
       '#empty_option' => $this->t('- Select -'),
     ];
     $form['parent']['actions'] = [
-      '#type' => 'actions'
+      '#type' => 'actions',
     ];
     $form['parent']['actions']['submit'] = [
       '#type' => 'submit',

core/modules/action/src/Plugin/Action/EmailAction.php

@@ -139,12 +139,11 @@ class EmailAction extends ConfigurableActionBase implements ContainerFactoryPlug
     }
     $params = ['context' => $this->configuration];
 
-    if ($this->mailManager->mail('system', 'action_send_email', $recipient, $langcode, $params)) {
+    $message = $this->mailManager->mail('system', 'action_send_email', $recipient, $langcode, $params);
+    // Error logging is handled by \Drupal\Core\Mail\MailManager::mail().
+    if ($message['result']) {
       $this->logger->notice('Sent email to %recipient', ['%recipient' => $recipient]);
     }
-    else {
-      $this->logger->error('Unable to send email to %recipient', ['%recipient' => $recipient]);
-    }
   }
 
   /**

core/modules/action/src/Plugin/Action/MessageAction.php

@@ -5,6 +5,7 @@ namespace Drupal\action\Plugin\Action;
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Action\ConfigurableActionBase;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Messenger\MessengerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Session\AccountInterface;
@@ -36,6 +37,13 @@ class MessageAction extends ConfigurableActionBase implements ContainerFactoryPl
    */
   protected $renderer;
 
+  /**
+   * The messenger.
+   *
+   * @var \Drupal\Core\Messenger\MessengerInterface
+   */
+  protected $messenger;
+
   /**
    * Constructs a MessageAction object.
    *
@@ -49,19 +57,22 @@ class MessageAction extends ConfigurableActionBase implements ContainerFactoryPl
    *   The token service.
    * @param \Drupal\Core\Render\RendererInterface $renderer
    *   The renderer.
+   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
+   *   The messenger.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, Token $token, RendererInterface $renderer) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, Token $token, RendererInterface $renderer, MessengerInterface $messenger) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
 
     $this->token = $token;
     $this->renderer = $renderer;
+    $this->messenger = $messenger;
   }
 
   /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
-    return new static($configuration, $plugin_id, $plugin_definition, $container->get('token'), $container->get('renderer'));
+    return new static($configuration, $plugin_id, $plugin_definition, $container->get('token'), $container->get('renderer'), $container->get('messenger'));
   }
 
   /**
@@ -77,7 +88,7 @@ class MessageAction extends ConfigurableActionBase implements ContainerFactoryPl
     ];
 
     // @todo Fix in https://www.drupal.org/node/2577827
-    drupal_set_message($this->renderer->renderPlain($build));
+    $this->messenger->addStatus($this->renderer->renderPlain($build));
   }
 
   /**