feature symfony#59967 [Mailer][TwigBridge] Add support for translatable subject (norkunas)

This PR was merged into the 7.3 branch.

Discussion
----------

[Mailer][TwigBridge] Add support for translatable subject

| Q             | A
| ------------- | ---
| Branch?       | 7.3
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Issues        | Fix symfony#54203
| License       | MIT

Commits
-------

97eb49b [Mailer][TwigBridge] Add support for translatable subject

Author: fabpot

src/Symfony/Bridge/Twig/CHANGELOG.md

@@ -6,6 +6,7 @@ CHANGELOG
 
  * Add `is_granted_for_user()` Twig function
  * Add `field_id()` Twig form helper function
+ * Add `TemplatedEmail::getTranslatableSubject()` method
 
 7.2
 ---

src/Symfony/Bridge/Twig/Mime/TemplatedEmail.php

@@ -18,11 +18,29 @@
  */
 class TemplatedEmail extends Email
 {
+    private string|\Stringable|null $subject = null;
     private ?string $htmlTemplate = null;
     private ?string $textTemplate = null;
     private ?string $locale = null;
     private array $context = [];
 
+    /**
+     * @return $this
+     */
+    public function subject(string|\Stringable $subject): static
+    {
+        parent::subject($subject);
+
+        $this->subject = $subject;
+
+        return $this;
+    }
+
+    public function getTranslatableSubject(): string|\Stringable|null
+    {
+        return $this->subject;
+    }
+
     /**
      * @return $this
      */
@@ -100,7 +118,7 @@ public function markAsRendered(): void
      */
     public function __serialize(): array
     {
-        return [$this->htmlTemplate, $this->textTemplate, $this->context, parent::__serialize(),  $this->locale];
+        return [$this->htmlTemplate, $this->textTemplate, $this->context, parent::__serialize(), $this->locale, $this->subject];
     }
 
     /**
@@ -110,6 +128,7 @@ public function __unserialize(array $data): void
     {
         [$this->htmlTemplate, $this->textTemplate, $this->context, $parentData] = $data;
         $this->locale = $data[4] ?? null;
+        $this->subject = $data[5] ?? null;
 
         parent::__unserialize($parentData);
     }

src/Symfony/Bridge/Twig/Tests/Mime/TemplatedEmailTest.php

@@ -20,7 +20,10 @@
 use Symfony\Component\Serializer\Normalizer\MimeMessageNormalizer;
 use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
 use Symfony\Component\Serializer\Normalizer\PropertyNormalizer;
+use Symfony\Component\Serializer\Normalizer\TranslatableNormalizer;
 use Symfony\Component\Serializer\Serializer;
+use Symfony\Component\Translation\IdentityTranslator;
+use Symfony\Component\Translation\TranslatableMessage;
 
 class TemplatedEmailTest extends TestCase
 {
@@ -44,19 +47,22 @@ public function testSerialize()
             ->htmlTemplate('text.html.twig')
             ->context($context = ['a' => 'b'])
             ->locale($locale = 'fr_FR')
+            ->subject($subject = new TranslatableMessage('hello {{ name }}', ['name' => 'John'], 'greetings'))
         ;
 
         $email = unserialize(serialize($email));
         $this->assertEquals('text.txt.twig', $email->getTextTemplate());
         $this->assertEquals('text.html.twig', $email->getHtmlTemplate());
         $this->assertEquals($context, $email->getContext());
         $this->assertEquals($locale, $email->getLocale());
+        $this->assertEquals($subject, $email->getTranslatableSubject());
     }
 
     public function testSymfonySerialize()
     {
         // we don't add from/sender to check that validation is not triggered to serialize an email
         $e = new TemplatedEmail();
+        $e->subject(new TranslatableMessage('hello.world'));
         $e->to('[email protected]');
         $e->textTemplate('email.txt.twig');
         $e->htmlTemplate('email.html.twig');
@@ -67,6 +73,7 @@ public function testSymfonySerialize()
 
         $expectedJson = <<<EOF
 {
+    "subject": "hello.world",
     "htmlTemplate": "email.html.twig",
     "textTemplate": "email.txt.twig",
     "locale": "en",
@@ -84,6 +91,15 @@ public function testSymfonySerialize()
         }
     ],
     "headers": {
+        "subject": [
+            {
+                "value": "hello.world",
+                "name": "Subject",
+                "lineLength": 76,
+                "lang": null,
+                "charset": "utf-8"
+            }
+        ],
         "to": [
             {
                 "addresses": [
@@ -108,6 +124,7 @@ public function testSymfonySerialize()
         $serializer = new Serializer([
             new ArrayDenormalizer(),
             new MimeMessageNormalizer($propertyNormalizer),
+            new TranslatableNormalizer(new IdentityTranslator()),
             new ObjectNormalizer(null, null, null, $extractor),
             $propertyNormalizer,
         ], [new JsonEncoder()]);

src/Symfony/Bundle/TwigBundle/Resources/config/mailer.php

@@ -18,7 +18,11 @@
 return static function (ContainerConfigurator $container) {
     $container->services()
         ->set('twig.mailer.message_listener', MessageListener::class)
-            ->args([null, service('twig.mime_body_renderer')])
+            ->args([
+                null,
+                service('twig.mime_body_renderer'),
+                '$translator' => service('translator')->ignoreOnInvalid(),
+            ])
             ->tag('kernel.event_subscriber')
 
         ->set('twig.mime_body_renderer', BodyRenderer::class)

src/Symfony/Component/Mailer/CHANGELOG.md

@@ -9,6 +9,7 @@ CHANGELOG
  * Add DSN param `source_ip` to allow binding to a (specific) IPv4 or IPv6 address.
  * Add DSN param `require_tls` to enforce use of TLS/STARTTLS
  * Add `DkimSignedMessageListener`, `SmimeEncryptedMessageListener`, and `SmimeSignedMessageListener`
+ * Add support for translatable subject in `TemplatedEmail`
 
 7.2
 ---

src/Symfony/Component/Mailer/EventListener/MessageListener.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\Mailer\EventListener;
 
+use Symfony\Bridge\Twig\Mime\TemplatedEmail;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\Mailer\Event\MessageEvent;
 use Symfony\Component\Mailer\Exception\InvalidArgumentException;
@@ -19,9 +20,11 @@
 use Symfony\Component\Mime\Header\Headers;
 use Symfony\Component\Mime\Header\MailboxListHeader;
 use Symfony\Component\Mime\Message;
+use Symfony\Component\Translation\TranslatableMessage;
+use Symfony\Contracts\Translation\TranslatorInterface;
 
 /**
- * Manipulates the headers and the body of a Message.
+ * Manipulates the headers, subject, and the body of a Message.
  *
  * @author Fabien Potencier <[email protected]>
  */
@@ -45,6 +48,7 @@ public function __construct(
         private ?Headers $headers = null,
         private ?BodyRendererInterface $renderer = null,
         array $headerRules = self::DEFAULT_RULES,
+        private ?TranslatorInterface $translator = null,
     ) {
         foreach ($headerRules as $headerName => $rule) {
             $this->addHeaderRule($headerName, $rule);
@@ -68,6 +72,7 @@ public function onMessage(MessageEvent $event): void
         }
 
         $this->setHeaders($message);
+        $this->translateSubject($message);
         $this->renderMessage($message);
     }
 
@@ -115,6 +120,15 @@ private function setHeaders(Message $message): void
         }
     }
 
+    private function translateSubject(Message $message): void
+    {
+        if (!$message instanceof TemplatedEmail || !$this->translator || !$message->getTranslatableSubject() instanceof TranslatableMessage) {
+            return;
+        }
+
+        $message->subject($message->getTranslatableSubject()->trans($this->translator, $message->getLocale()));
+    }
+
     private function renderMessage(Message $message): void
     {
         if (!$this->renderer) {

src/Symfony/Component/Mailer/Tests/EventListener/MessageListenerTest.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\Mailer\Tests\EventListener;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Bridge\Twig\Mime\TemplatedEmail;
 use Symfony\Component\Mailer\Envelope;
 use Symfony\Component\Mailer\Event\MessageEvent;
 use Symfony\Component\Mailer\EventListener\MessageListener;
@@ -20,6 +21,8 @@
 use Symfony\Component\Mime\Header\MailboxListHeader;
 use Symfony\Component\Mime\Header\UnstructuredHeader;
 use Symfony\Component\Mime\Message;
+use Symfony\Component\Translation\TranslatableMessage;
+use Symfony\Contracts\Translation\TranslatorInterface;
 
 class MessageListenerTest extends TestCase
 {
@@ -114,4 +117,25 @@ public static function provideHeaders(): iterable
         ];
         yield 'Capitalized header rule (case-insensitive), replace if set' => [$initialHeaders, $defaultHeaders, $defaultHeaders, $rules];
     }
+
+    public function testTranslatableSubject()
+    {
+        $message = new TemplatedEmail();
+        $message->subject(new TranslatableMessage('hello.world'));
+        $listener = new MessageListener(translator: new class implements TranslatorInterface {
+            public function trans(string $id, array $parameters = [], ?string $domain = null, ?string $locale = null): string
+            {
+                return 'Hello World';
+            }
+
+            public function getLocale(): string
+            {
+                return 'en';
+            }
+        });
+        $event = new MessageEvent($message, new Envelope(new Address('[email protected]'), [new Address('[email protected]')]), 'smtp');
+        $listener->onMessage($event);
+
+        $this->assertSame('Hello World', $message->getSubject());
+    }
 }

src/Symfony/Component/Mailer/composer.json

@@ -21,13 +21,14 @@
         "psr/event-dispatcher": "^1",
         "psr/log": "^1|^2|^3",
         "symfony/event-dispatcher": "^6.4|^7.0",
-        "symfony/mime": "^7.2",
+        "symfony/mime": "^7.3",
         "symfony/service-contracts": "^2.5|^3"
     },
     "require-dev": {
         "symfony/console": "^6.4|^7.0",
         "symfony/http-client": "^6.4|^7.0",
         "symfony/messenger": "^6.4|^7.0",
+        "symfony/translation": "^6.4|^7.0",
         "symfony/twig-bridge": "^6.4|^7.0"
     },
     "conflict": {

src/Symfony/Component/Mime/Email.php

@@ -58,9 +58,9 @@ class Email extends Message
     /**
      * @return $this
      */
-    public function subject(string $subject): static
+    public function subject(string|\Stringable $subject): static
     {
-        return $this->setHeaderBody('Text', 'Subject', $subject);
+        return $this->setHeaderBody('Text', 'Subject', (string) $subject);
     }
 
     public function getSubject(): ?string