feat: provide old content to Revised event

framework/core/src/Post/CommentPost.php

@@ -75,12 +75,14 @@ public static function reply($discussionId, $content, $userId, $ipAddress, User
     public function revise($content, User $actor)
     {
         if ($this->content !== $content) {
+            $oldContent = $this->content;
+
             $this->setContentAttribute($content, $actor);
 
             $this->edited_at = Carbon::now();
             $this->edited_user_id = $actor->id;
 
-            $this->raise(new Revised($this));
+            $this->raise(new Revised($this, $actor, $oldContent));
         }
 
         return $this;

framework/core/src/Post/Event/Revised.php

@@ -15,7 +15,7 @@
 class Revised
 {
     /**
-     * @var \Flarum\Post\CommentPost
+     * @var CommentPost
      */
     public $post;
 
@@ -25,11 +25,18 @@ class Revised
     public $actor;
 
     /**
-     * @param \Flarum\Post\CommentPost $post
+     * We manually set the old content because at this stage the post
+     * has already been updated with the new content. So the original
+     * content is not available anymore.
+     *
+     * @var string
      */
-    public function __construct(CommentPost $post, User $actor = null)
+    public $oldContent;
+
+    public function __construct(CommentPost $post, User $actor, string $oldContent)
     {
         $this->post = $post;
         $this->actor = $actor;
+        $this->oldContent = $oldContent;
     }
 }