Fix From/Sender handling in Emails

Author: fabpot

EventListener/EnvelopeListener.php

@@ -14,6 +14,7 @@
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\Mailer\Event\MessageEvent;
 use Symfony\Component\Mime\Address;
+use Symfony\Component\Mime\Message;
 
 /**
  * Manipulates the Envelope of a Message.
@@ -43,6 +44,13 @@ public function onMessage(MessageEvent $event): void
     {
         if ($this->sender) {
             $event->getEnvelope()->setSender($this->sender);
+
+            $message = $event->getMessage();
+            if ($message instanceof Message) {
+                if (!$message->getHeaders()->has('Sender') && !$message->getHeaders()->has('From')) {
+                    $message->getHeaders()->addMailboxHeader('Sender', $this->sender->getAddress());
+                }
+            }
         }
 
         if ($this->recipients) {

Transport/AbstractTransport.php

@@ -63,10 +63,6 @@ public function send(RawMessage $message, Envelope $envelope = null): ?SentMessa
             $envelope = $event->getEnvelope();
         }
 
-        if (!$envelope->getRecipients()) {
-            return null;
-        }
-
         $message = new SentMessage($message, $envelope);
         $this->doSend($message);