<?php

namespace FluxBB\Controllers;

use FluxBB\Models\Post;
use FluxBB\Repositories\Topics;
use FluxBB\Services\CreateReply;
use FluxBB\Services\CreateReplyObserver;
use Illuminate\Support\MessageBag;
use Auth;
use Input;
use Redirect;

class PostsController extends BaseController implements
    CreateReplyObserver
{
    public function postReply($tid)
    {
        $topic = $this->topics->findOrFail($tid);

        $service = new CreateReply($this, $this->topics);
        return $service->createReply($topic, Auth::user(), Input::get('req_message'));
    }

    public function replyCreated(Post $post)
    {
        return Redirect::route('viewpost', array('id' => $post->id));
    }

    public function replyValidationFailed(Post $post, MessageBag $errors)
    {
        return Redirect::route('posting@reply', array($post->topic_id))
                       ->withInput()
                       ->withErrors($errors);
    }
}

<?php

namespace FluxBB\Controllers;

use FluxBB\Models\Post;
use FluxBB\Repositories\Topics;
use FluxBB\Services\CreateReply;
use FluxBB\Services\CreateReplyObserver;
use Illuminate\Support\MessageBag;
use Auth;
use Input;
use Redirect;

class PostsController extends BaseController implements
    CreateReplyObserver
{
    public function postReply($tid)
    {
        $topic = $this->topics->find($tid); // TODO: 404?

        $service = new CreateReply($this, $this->topics);
        return $service->createReply($topic, Auth::user(), Input::get('req_message'));
    }

    public function replyCreated(Post $post)
    {
        return Redirect::route('viewpost', array('id' => $post->id));
    }

    public function replyValidationFailed(Post $post, MessageBag $errors)
    {
        return Redirect::route('posting@reply', array($post->topic_id))
                       ->withInput()
                       ->withErrors($errors);
    }
}

--- 
+++ 
@@ -16,7 +16,7 @@
 {
     public function postReply($tid)
     {
-        $topic = $this->topics->find($tid); // TODO: 404?
+        $topic = $this->topics->findOrFail($tid);
 
         $service = new CreateReply($this, $this->topics);
         return $service->createReply($topic, Auth::user(), Input::get('req_message'));
Throw exception if topic cannot be found.
