fix(jsonld): prefix error @type with hydra:

features/main/relation.feature

@@ -493,7 +493,7 @@ Feature: Relations support
       "properties": {
         "@type": {
           "type": "string",
-          "pattern": "^Error$"
+          "pattern": "^hydra:Error$"
         },
         "title": {
           "type": "string",

features/serializer/vo_relations.feature

@@ -148,7 +148,7 @@ Feature: Value object as ApiResource
       "properties": {
         "@type": {
           "type": "string",
-          "pattern": "^Error$"
+          "pattern": "^hydra:Error$"
         },
         "title": {
           "type": "string",

src/JsonLd/Serializer/ErrorNormalizer.php

@@ -28,12 +28,17 @@ public function __construct(private readonly NormalizerInterface $inner, private
 
     public function normalize(mixed $object, ?string $format = null, array $context = []): array|string|int|float|bool|\ArrayObject|null
     {
+        $context += $this->defaultContext;
         $normalized = $this->inner->normalize($object, $format, $context);
-        $hydraPrefix = $this->getHydraPrefix($context + $this->defaultContext);
+        $hydraPrefix = $this->getHydraPrefix($context);
         if (!$hydraPrefix) {
             return $normalized;
         }
 
+        if ('Error' === $normalized['@type']) {
+            $normalized['@type'] = 'hydra:Error';
+        }
+
         if (isset($normalized['description'])) {
             $normalized['hydra:description'] = $normalized['description'];
         }

tests/JsonLd/Serializer/ErrorNormalizerTest.php

@@ -0,0 +1,35 @@
+<?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\JsonLd\Serializer;
+
+use ApiPlatform\JsonLd\ContextBuilder;
+use ApiPlatform\JsonLd\Serializer\ErrorNormalizer;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+
+final class ErrorNormalizerTest extends TestCase
+{
+    public function testAddHydraPrefix(): void
+    {
+        $provider = $this->createMock(NormalizerInterface::class);
+        $provider->method('normalize')->willReturn(['@type' => 'Error', 'title' => 'foo', 'description' => 'bar']);
+        $errorNormalizer = new ErrorNormalizer($provider, ['hydra_prefix' => ContextBuilder::HYDRA_CONTEXT_HAS_PREFIX]);
+        $res = $errorNormalizer->normalize(new \stdClass());
+        $this->assertEquals('hydra:Error', $res['@type']);
+        $this->assertArrayHasKey('hydra:description', $res);
+        $this->assertEquals($res['hydra:description'], $res['description']);
+        $this->assertArrayHasKey('hydra:title', $res);
+        $this->assertEquals($res['hydra:title'], $res['title']);
+    }
+}