Pass a translator instance to getEmailSubject on MailableInterface (#2244)

* Pass a translator instance to getMailSubject (breaking change)

* Temporarily comment out getEmailSubject to avoid BC breaks

src/Notification/MailableInterface.php

@@ -9,6 +9,8 @@
 
 namespace Flarum\Notification;
 
+use Symfony\Component\Translation\TranslatorInterface;
+
 interface MailableInterface
 {
     /**
@@ -23,5 +25,7 @@ interface MailableInterface
      *
      * @return string
      */
-    public function getEmailSubject();
+    // TODO: This is temporarily commented out to avoid BC breaks between beta 13 and beta 14.
+    // It should be uncommented before beta 15.
+    // public function getEmailSubject(TranslatorInterface $translator);
 }

src/Notification/NotificationMailer.php

@@ -12,6 +12,7 @@ namespace Flarum\Notification;
 use Flarum\User\User;
 use Illuminate\Contracts\Mail\Mailer;
 use Illuminate\Mail\Message;
+use Symfony\Component\Translation\TranslatorInterface;
 
 class NotificationMailer
 {
@@ -21,11 +22,18 @@ class NotificationMailer
     protected $mailer;
 
     /**
-     * @param Mailer $mailer
+     * @var TranslatorInterface
      */
-    public function __construct(Mailer $mailer)
+    protected $translator;
+
+    /**
+     * @param Mailer $mailer
+     * @param TranslatorInterface $translator
+     */
+    public function __construct(Mailer $mailer, TranslatorInterface $translator)
     {
         $this->mailer = $mailer;
+        $this->translator = $translator;
     }
 
     /**
@@ -39,7 +47,7 @@ class NotificationMailer
             compact('blueprint', 'user'),
             function (Message $message) use ($blueprint, $user) {
                 $message->to($user->email, $user->username)
-                        ->subject($blueprint->getEmailSubject());
+                        ->subject($blueprint->getEmailSubject($this->translator));
             }
         );
     }