bug #32951 [Mailer] Fix dispatcher not available in Mailer (fabpot)

This PR was merged into the 4.4 branch.

Discussion
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[Mailer] Fix dispatcher not available in Mailer

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

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 - Bug fixes must be submitted against the lowest maintained branch where they apply
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Commits
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77951de [Mailer] fixed dispatcher not available in Mailer

src/Symfony/Bundle/FrameworkBundle/Resources/config/mailer.xml

@@ -8,6 +8,7 @@
         <service id="mailer.mailer" class="Symfony\Component\Mailer\Mailer">
             <argument type="service" id="mailer.default_transport" />
             <argument type="service" id="messenger.default_bus" on-invalid="ignore" />
+            <argument type="service" id="event_dispatcher" on-invalid="ignore" />
         </service>
         <service id="mailer" alias="mailer.mailer" />
         <service id="Symfony\Component\Mailer\MailerInterface" alias="mailer.mailer" />

src/Symfony/Component/Mailer/Mailer.php

@@ -17,6 +17,7 @@
 use Symfony\Component\Mailer\Transport\TransportInterface;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Mime\RawMessage;
+use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
@@ -25,8 +26,9 @@ class Mailer implements MailerInterface
 {
     private $transport;
     private $bus;
+    private $dispatcher;
 
-    public function __construct(TransportInterface $transport, MessageBusInterface $bus = null)
+    public function __construct(TransportInterface $transport, MessageBusInterface $bus = null, EventDispatcherInterface $dispatcher = null)
     {
         $this->transport = $transport;
         $this->bus = $bus;
@@ -40,18 +42,20 @@ public function send(RawMessage $message, SmtpEnvelope $envelope = null): void
             return;
         }
 
-        $message = clone $message;
-        if (null !== $envelope) {
-            $envelope = clone $envelope;
-        } else {
-            try {
-                $envelope = new DelayedSmtpEnvelope($message);
-            } catch (\Exception $e) {
-                throw new TransportException('Cannot send message without a valid envelope.', 0, $e);
+        if (null !== $this->dispatcher) {
+            $message = clone $message;
+            if (null !== $envelope) {
+                $envelope = clone $envelope;
+            } else {
+                try {
+                    $envelope = new DelayedSmtpEnvelope($message);
+                } catch (\Exception $e) {
+                    throw new TransportException('Cannot send message without a valid envelope.', 0, $e);
+                }
             }
+            $event = new MessageEvent($message, $envelope, $this->transport->getName());
+            $this->dispatcher->dispatch($event);
         }
-        $event = new MessageEvent($message, $envelope, $this->transport->getName());
-        $this->dispatcher->dispatch($event);
 
         $this->bus->dispatch(new SendEmailMessage($message, $envelope));
     }