Make discussion slug URL parameter optional

src/Forum/Actions/DiscussionAction.php

@@ -16,7 +16,7 @@ class DiscussionAction extends ClientAction
         $page = max(1, array_get($queryParams, 'page'));
 
         $params = [
-            'id' => array_get($routeParams, 'id'),
+            'id' => (int) array_get($routeParams, 'id'),
             'page' => [
                 'near' => array_get($routeParams, 'near'),
                 'offset' => ($page - 1) * 20,

src/Forum/ForumServiceProvider.php

@@ -57,7 +57,7 @@ class ForumServiceProvider extends ServiceProvider
         );
 
         $routes->get(
-            '/d/{id:\d+}[/{slug}[/{near}]]',
+            '/d/{id:\d+(?:-[^/]*)?}[/{near}]',
             'flarum.forum.discussion',
             $this->action('Flarum\Forum\Actions\DiscussionAction')
         );