fix: error formats

src/Symfony/EventListener/ErrorListener.php

@@ -68,8 +68,9 @@ public function __construct(
     protected function duplicateRequest(\Throwable $exception, Request $request): Request
     {
         $format = $this->getRequestFormat($request, $this->errorFormats, false);
-        // Because ErrorFormatGuesser is buggy in some cases
-        $request->setRequestFormat($format);
+        // Reset the request format as it may be that the original request format negotiation won't have the same result
+        // when an error occurs
+        $request->setRequestFormat(null);
         $apiOperation = $this->initializeOperation($request);
 
         // TODO: add configuration flag to:

src/Symfony/Routing/ApiLoader.php

@@ -90,11 +90,10 @@ public function load(mixed $data, ?string $type = null): RouteCollection
                         $path,
                         [
                             '_controller' => $controller ?? 'api_platform.action.placeholder',
-                            '_format' => null,
                             '_stateless' => $operation->getStateless(),
                             '_api_resource_class' => $resourceClass,
                             '_api_operation_name' => $operationName,
-                        ] + ($operation->getDefaults() ?? []),
+                        ] + ($operation->getDefaults() ?? []) + ['_format' => null],
                         $operation->getRequirements() ?? [],
                         $operation->getOptions() ?? [],
                         $operation->getHost() ?? '',

tests/Fixtures/TestBundle/ApiResource/XmlWithJsonError.php

@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\ApiResource;
+
+use ApiPlatform\Metadata\Post;
+
+#[Post(inputFormats: ['xml' => 'application/xml'], uriVariables: ['id'])]
+class XmlWithJsonError
+{
+}

tests/Functional/ErrorTest.php

@@ -15,6 +15,7 @@
 
 use ApiPlatform\State\ApiResource\Error;
 use ApiPlatform\Symfony\Bundle\Test\ApiTestCase;
+use ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\XmlWithJsonError;
 use ApiPlatform\Tests\SetupClassResourcesTrait;
 use PHPUnit\Framework\Attributes\DataProvider;
 
@@ -29,7 +30,7 @@ final class ErrorTest extends ApiTestCase
      */
     public static function getResources(): array
     {
-        return [Error::class];
+        return [Error::class, XmlWithJsonError::class];
     }
 
     #[DataProvider('formatsProvider')]
@@ -79,4 +80,15 @@ public static function formatsProvider(): array
             ],
         ];
     }
+
+    public function testJsonError(): void
+    {
+        self::createClient()->request('POST', '/xml_with_json_errors', [
+            'headers' => ['content-type' => 'application/json'],
+            'body' => '<xml></xml>',
+        ]);
+
+        $this->assertResponseStatusCodeSame(415);
+        $this->assertJsonContains(['detail' => 'The content-type "application/json" is not supported. Supported MIME types are "application/xml".']);
+    }
 }

tests/Symfony/Routing/ApiLoaderTest.php

@@ -321,7 +321,7 @@ private function getRoute(string $path, string $controller, ?bool $stateless, st
             $path,
             [
                 '_controller' => $controller,
-                '_format' => null,
+                '_format' => $extraDefaults['_format'] ?? null,
                 '_stateless' => $stateless,
                 '_api_resource_class' => $resourceClass,
                 '_api_operation_name' => $operationName,