[2.x] fix(tags): update tag metadata when a pending discussion is approved

extensions/tags/src/Listener/UpdateTagMetadata.php

@@ -39,13 +39,29 @@ public function subscribe(Dispatcher $events): void
         $events->listen(PostDeleted::class, $this->whenPostIsDeleted(...));
         $events->listen(PostHidden::class, $this->whenPostIsHidden(...));
         $events->listen(PostRestored::class, $this->whenPostIsRestored(...));
+
+        // Refresh metadata skipped while a post was pending approval.
+        $events->listen('Flarum\Approval\Event\PostWasApproved', $this->whenPostIsApproved(...));
     }
 
     public function whenDiscussionIsStarted(Started $event): void
     {
         $this->updateTags($event->discussion, 1);
     }
 
+    public function whenPostIsApproved(object $event): void
+    {
+        $discussion = $event->post->discussion;
+        $delta = $event->post->number === 1 ? 1 : 0;
+
+        // The visibility change may not be persisted yet; if so, defer to its save.
+        if ($discussion->is_private) {
+            $discussion->afterSave(fn (Discussion $discussion) => $this->updateTags($discussion, $delta));
+        } else {
+            $this->updateTags($discussion, $delta);
+        }
+    }
+
     public function whenDiscussionWasTagged(DiscussionWasTagged $event): void
     {
         $oldTags = Tag::whereIn('id', Arr::pluck($event->oldTags, 'id'))->get();