Display error message on 500 error page

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/EventListener/ExceptionListener.php

@@ -34,7 +34,10 @@ class ExceptionListener
         }
 
         $response = new Response(
-            $this->twig->render($template, ['status_code' => $statusCode]),
+            $this->twig->render($template, [
+                'status_code' => $statusCode,
+                'error_message' => $exception->getMessage(),
+            ]),
             $statusCode,
         );
 

templates/error/500.html.twig

@@ -13,7 +13,12 @@
             <div class="border-4 border-gray-900 bg-white shadow-[6px_6px_0px_rgba(0,0,0,1)] p-12">
                 <div class="text-8xl font-black uppercase tracking-tighter mb-4">{{ status_code }}</div>
                 <h1 class="text-3xl font-black uppercase tracking-tighter italic mb-4">Erreur serveur</h1>
-                <p class="font-bold text-gray-500 italic mb-8">Une erreur inattendue s'est produite. Nos equipes ont ete notifiees.</p>
+                <p class="font-bold text-gray-500 italic mb-4">Une erreur inattendue s'est produite. Nos equipes ont ete notifiees.</p>
+                {% if error_message is defined and error_message %}
+                <div class="card-brutal-red mb-8">
+                    <p class="text-sm font-mono break-all">{{ error_message }}</p>
+                </div>
+                {% endif %}
                 <a href="/" class="btn-brutal font-black uppercase text-sm tracking-widest hover:bg-indigo-600 hover:text-white transition-all">
                     Retour a l'accueil
                 </a>

tests/EventListener/ExceptionListenerTest.php

@@ -43,7 +43,7 @@ class ExceptionListenerTest extends TestCase
         $twig = $this->createMock(Environment::class);
         $twig->expects(self::once())
             ->method('render')
-            ->with('error/404.html.twig', ['status_code' => 404])
+            ->with('error/404.html.twig', ['status_code' => 404, 'error_message' => 'Not found'])
             ->willReturn('<h1>404</h1>');
 
         $listener = new ExceptionListener($twig, 'prod');
@@ -61,7 +61,7 @@ class ExceptionListenerTest extends TestCase
         $twig = $this->createMock(Environment::class);
         $twig->expects(self::once())
             ->method('render')
-            ->with('error/500.html.twig', ['status_code' => 500])
+            ->with('error/500.html.twig', ['status_code' => 500, 'error_message' => 'Server error'])
             ->willReturn('<h1>500</h1>');
 
         $listener = new ExceptionListener($twig, 'prod');
@@ -78,7 +78,7 @@ class ExceptionListenerTest extends TestCase
         $twig = $this->createMock(Environment::class);
         $twig->expects(self::once())
             ->method('render')
-            ->with('error/500.html.twig', ['status_code' => 403])
+            ->with('error/500.html.twig', ['status_code' => 403, 'error_message' => 'Forbidden'])
             ->willReturn('<h1>403</h1>');
 
         $listener = new ExceptionListener($twig, 'prod');