Render BCMath\Number (PHP 8.4+) as string instead of object

src/JsonSchema/Metadata/Property/Factory/SchemaPropertyMetadataFactory.php

@@ -319,6 +319,10 @@ private function getClassSchemaDefinition(?string $className, ?bool $readableLin
             return ['type' => 'string', 'format' => 'binary'];
         }
 
+        if (is_a($className, \BcMath\Number::class, true)) {
+            return ['type' => 'string', 'format' => 'string'];
+        }
+
         $isResourceClass = $this->isResourceClass($className);
         if (!$isResourceClass && is_a($className, \BackedEnum::class, true)) {
             $enumCases = array_map(static fn (\BackedEnum $enum): string|int => $enum->value, $className::cases());
@@ -509,6 +513,13 @@ private function getLegacyClassType(?string $className, bool $nullable, ?bool $r
             ];
         }
 
+        if (is_a($className, \BcMath\Number::class, true)) {
+            return [
+                'type' => 'string',
+                'format' => 'string',
+            ];
+        }
+
         $isResourceClass = $this->isResourceClass($className);
         if (!$isResourceClass && is_a($className, \BackedEnum::class, true)) {
             $enumCases = array_map(static fn (\BackedEnum $enum): string|int => $enum->value, $className::cases());

src/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php

@@ -66,6 +66,7 @@
 use Symfony\Component\JsonStreamer\JsonStreamWriter;
 use Symfony\Component\ObjectMapper\ObjectMapper;
 use Symfony\Component\Serializer\NameConverter\CamelCaseToSnakeCaseNameConverter;
+use Symfony\Component\Serializer\Normalizer\NumberNormalizer;
 use Symfony\Component\Uid\AbstractUid;
 use Symfony\Component\Validator\Validator\ValidatorInterface;
 use Symfony\Component\Yaml\Yaml;
@@ -267,6 +268,15 @@ private function registerCommonConfiguration(ContainerBuilder $container, array
             $loader->load('symfony/uid.php');
         }
 
+        // symfony/serializer:7.3 added the NumberNormalizer
+        // symfony/framework-bundle:7.3 added the serializer.normalizer.number` service
+        // if symfony/serializer >= 7.3 and symfony/framework-bundle < 7.3, the service is registred
+        if (class_exists(NumberNormalizer::class) && !$container->has('serializer.normalizer.number')) {
+            $numberNormalizerDefinition = new Definition(NumberNormalizer::class);
+            $numberNormalizerDefinition->addTag('serializer.normalizer', ['built_in' => true, 'priority' => -915]);
+            $container->setDefinition('serializer.normalizer.number', $numberNormalizerDefinition);
+        }
+
         $defaultContext = ['hydra_prefix' => $config['serializer']['hydra_prefix']] + ($container->hasParameter('serializer.default_context') ? $container->getParameter('serializer.default_context') : []);
 
         $container->setParameter('api_platform.serializer.default_context', $defaultContext);

tests/Fixtures/TestBundle/ApiResource/MathNumber.php

@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <[email protected]>
+ *
+ * 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\ApiProperty;
+use ApiPlatform\Metadata\Get;
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\Metadata\Post;
+
+if (class_exists(\BcMath\Number::class)) {
+    #[Get(
+        provider: [self::class, 'provide'],
+    )]
+    #[Post]
+    class MathNumber
+    {
+        #[ApiProperty(identifier: true)]
+        public int $id;
+
+        #[ApiProperty(property: 'value')]
+        public ?\BcMath\Number $value;
+
+        public static function provide(Operation $operation, array $uriVariables = [], array $context = []): self
+        {
+            $mathNumber = new self();
+            $mathNumber->id = $uriVariables['id'];
+            $mathNumber->value = new \BcMath\Number('300.55');
+
+            return $mathNumber;
+        }
+    }
+}

tests/Functional/MathNumberTest.php

@@ -0,0 +1,81 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <[email protected]>
+ *
+ * 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\Functional;
+
+use ApiPlatform\Symfony\Bundle\Test\ApiTestCase;
+use ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\MathNumber;
+use ApiPlatform\Tests\SetupClassResourcesTrait;
+use PHPUnit\Framework\Attributes\RequiresPhp;
+use PHPUnit\Framework\Attributes\RequiresPhpExtension;
+use Symfony\Component\Serializer\Normalizer\NumberNormalizer;
+
+#[RequiresPhp('^8.4')]
+#[RequiresPhpExtension('bcmath')]
+final class MathNumberTest extends ApiTestCase
+{
+    use SetupClassResourcesTrait;
+
+    protected static ?bool $alwaysBootKernel = false;
+
+    /**
+     * @return class-string[]
+     */
+    public static function getResources(): array
+    {
+        return [MathNumber::class];
+    }
+
+    protected function setUp(): void
+    {
+        if (!class_exists(NumberNormalizer::class)) {
+            $this->markTestSkipped('Requires BcMath/Number and symfony/serialiser >=7.3');
+        }
+
+        parent::setUp();
+    }
+
+    public function testGetMathNumber(): void
+    {
+        self::createClient()->request('GET', '/math_numbers/1', ['headers' => ['Accept' => 'application/ld+json']]);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertJsonEquals([
+            '@context' => '/contexts/MathNumber',
+            '@id' => '/math_numbers/1',
+            '@type' => 'MathNumber',
+            'id' => 1,
+            'value' => '300.55',
+        ]);
+    }
+
+    public function testPostMathNumber(): void
+    {
+        self::createClient()->request('POST', '/math_numbers', [
+            'headers' => ['Content-Type' => 'application/ld+json'],
+            'json' => [
+                'id' => 2,
+                'value' => '120.23',
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertJsonEquals([
+            '@context' => '/contexts/MathNumber',
+            '@id' => '/math_numbers/2',
+            '@type' => 'MathNumber',
+            'id' => 2,
+            'value' => '120.23',
+        ]);
+    }
+}