Fixing check for swiftmailer in EmailSenderListener

CHANGELOG

@@ -1,3 +1,10 @@
+**Swiftmailer will stop being maintained at the end of November 2021.**
+
+Please, move to Symfony Mailer at your earliest convenience.
+Symfony Mailer is the next evolution of Swiftmailer.
+It provides the same features with support for modern PHP code and support for third-party providers.
+See https://symfony.com/doc/current/mailer.html for more information.
+
 # 3.5.0
 
  * Fix support for "stream_options" in configuration

DependencyInjection/Compiler/EnsureNoHotPathPass.php

@@ -20,7 +20,7 @@ class EnsureNoHotPathPass extends AbstractRecursivePass
 {
     protected function processValue($value, $isRoot = false)
     {
-        if ($value instanceof Definition && 0 === strpos($value->getClass(), 'Swift_')) {
+        if ($value instanceof Definition && null !== ($class = $value->getClass()) && 0 === strpos($class, 'Swift_')) {
             $value->clearTag('container.hot_path');
         }
 

EventListener/EmailSenderListener.php

@@ -45,7 +45,7 @@ public function onException()
 
     public function onTerminate()
     {
-        if (!$this->container->has('mailer') || $this->wasExceptionThrown) {
+        if ((!$this->container->has('mailer') && !$this->container->has('swiftmailer.mailer.default')) || $this->wasExceptionThrown) {
             return;
         }
         $mailers = array_keys($this->container->getParameter('swiftmailer.mailers'));

Resources/doc/index.rst

@@ -1,6 +1,12 @@
 Installation
 ============
 
+**Swiftmailer will stop being maintained at the end of November 2021.**
+
+Please, move to `Symfony Mailer <https://symfony.com/doc/current/mailer.html>`_ at your earliest convenience.
+`Symfony Mailer <https://symfony.com/doc/current/mailer.html>`_ is the next evolution of Swiftmailer.
+It provides the same features with support for modern PHP code and support for third-party providers.
+
 Step 1: Download the Bundle
 ---------------------------