[JsonStreamer] Add synthetic properties support

src/Symfony/Component/JsonStreamer/CHANGELOG.md

@@ -8,6 +8,7 @@ CHANGELOG
  * Remove `nikic/php-parser` dependency
  * Add `_current_object` to the context passed to value transformers during write operations
  * Add `include_null_properties` option to encode the properties with `null` value
+ * Add synthetic properties support
 
 7.3
 ---

src/Symfony/Component/JsonStreamer/Mapping/PropertyMetadata.php

@@ -25,19 +25,31 @@ final class PropertyMetadata
      * @param list<string|\Closure> $streamToNativeValueTransformers
      */
     public function __construct(
-        private string $name,
+        private ?string $name,
         private Type $type,
         private array $nativeToStreamValueTransformers = [],
         private array $streamToNativeValueTransformers = [],
     ) {
     }
 
-    public function getName(): string
+    /**
+     * @param list<string|\Closure> $nativeToStreamValueTransformers
+     * @param list<string|\Closure> $streamToNativeValueTransformers
+     */
+    public static function createSynthetic(
+        Type $type,
+        array $nativeToStreamValueTransformers = [],
+        array $streamToNativeValueTransformers = [],
+    ): self {
+        return new self(null, $type, $nativeToStreamValueTransformers, $streamToNativeValueTransformers);
+    }
+
+    public function getName(): ?string
     {
         return $this->name;
     }
 
-    public function withName(string $name): self
+    public function withName(?string $name): self
     {
         return new self($name, $this->type, $this->nativeToStreamValueTransformers, $this->streamToNativeValueTransformers);
     }

src/Symfony/Component/JsonStreamer/Mapping/Read/AttributePropertyMetadataLoader.php

@@ -42,8 +42,12 @@ public function load(string $className, array $options = [], array $context = []
         $result = [];
 
         foreach ($initialResult as $initialStreamedName => $initialMetadata) {
+            if (!$initialName = $initialMetadata->getName()) {
+                continue;
+            }
+
             try {
-                $propertyReflection = new \ReflectionProperty($className, $initialMetadata->getName());
+                $propertyReflection = new \ReflectionProperty($className, $initialName);
             } catch (\ReflectionException $e) {
                 throw new RuntimeException($e->getMessage(), $e->getCode(), $e);
             }

src/Symfony/Component/JsonStreamer/Mapping/Write/AttributePropertyMetadataLoader.php

@@ -42,8 +42,12 @@ public function load(string $className, array $options = [], array $context = []
         $result = [];
 
         foreach ($initialResult as $initialStreamedName => $initialMetadata) {
+            if (!$initialName = $initialMetadata->getName()) {
+                continue;
+            }
+
             try {
-                $propertyReflection = new \ReflectionProperty($className, $initialMetadata->getName());
+                $propertyReflection = new \ReflectionProperty($className, $initialName);
             } catch (\ReflectionException $e) {
                 throw new RuntimeException($e->getMessage(), $e->getCode(), $e);
             }

src/Symfony/Component/JsonStreamer/Read/StreamReaderGenerator.php

@@ -127,6 +127,10 @@ private function createDataModel(Type $type, array $options = [], array $context
             $propertiesMetadata = $this->propertyMetadataLoader->load($className, $options, $context);
 
             foreach ($propertiesMetadata as $streamedName => $propertyMetadata) {
+                if (!$propertyMetadata->getName()) {
+                    continue;
+                }
+
                 $propertiesNodes[$streamedName] = [
                     'name' => $propertyMetadata->getName(),
                     'value' => $this->createDataModel($propertyMetadata->getType(), $options, $context),

src/Symfony/Component/JsonStreamer/Tests/Fixtures/Mapping/SyntheticPropertyMetadataLoader.php

@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\JsonStreamer\Tests\Fixtures\Mapping;
+
+use Symfony\Component\JsonStreamer\Mapping\PropertyMetadata;
+use Symfony\Component\JsonStreamer\Mapping\PropertyMetadataLoaderInterface;
+use Symfony\Component\TypeInfo\Type;
+
+final class SyntheticPropertyMetadataLoader implements PropertyMetadataLoaderInterface
+{
+    public function load(string $className, array $options = [], array $context = []): array
+    {
+        return [
+            'synthetic' => PropertyMetadata::createSynthetic(Type::true(), [
+                self::true(...),
+            ]),
+        ];
+    }
+
+    public static function true(): true
+    {
+        return true;
+    }
+}

src/Symfony/Component/JsonStreamer/Tests/Fixtures/Model/DummyWithSyntheticProperties.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Symfony\Component\JsonStreamer\Tests\Fixtures\Model;
+
+class DummyWithSyntheticProperties
+{
+}

src/Symfony/Component/JsonStreamer/Tests/JsonStreamReaderTest.php

@@ -12,14 +12,17 @@
 namespace Symfony\Component\JsonStreamer\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Psr\Container\ContainerInterface;
 use Symfony\Component\JsonStreamer\JsonStreamReader;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Enum\DummyBackedEnum;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Mapping\SyntheticPropertyMetadataLoader;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\ClassicDummy;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithDateTimes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithGenerics;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNameAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNullableProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithPhpDoc;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithSyntheticProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithValueTransformerAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\ValueTransformer\DivideStringAndCastToIntValueTransformer;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\ValueTransformer\StringToBooleanValueTransformer;
@@ -176,6 +179,16 @@ public function testReadObjectWithDateTimes()
         }, '{"interface":"2024-11-20","immutable":"2025-11-20"}', Type::object(DummyWithDateTimes::class));
     }
 
+    public function testReadObjectWithSyntheticProperties()
+    {
+        $reader = new JsonStreamReader($this->createMock(ContainerInterface::class), new SyntheticPropertyMetadataLoader(), $this->streamReadersDir, $this->lazyGhostsDir);
+
+        $this->assertRead($reader, function (mixed $read) {
+            $this->assertInstanceOf(DummyWithSyntheticProperties::class, $read);
+            $this->assertSame([], get_object_vars($read));
+        }, '{"synthetic":true}', Type::object(DummyWithSyntheticProperties::class));
+    }
+
     public function testCreateStreamReaderFile()
     {
         $reader = JsonStreamReader::create(streamReadersDir: $this->streamReadersDir, lazyGhostsDir: $this->lazyGhostsDir);

src/Symfony/Component/JsonStreamer/Tests/JsonStreamWriterTest.php

@@ -13,9 +13,11 @@
 
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
+use Psr\Container\ContainerInterface;
 use Symfony\Component\JsonStreamer\Exception\NotEncodableValueException;
 use Symfony\Component\JsonStreamer\JsonStreamWriter;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Enum\DummyBackedEnum;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Mapping\SyntheticPropertyMetadataLoader;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\ClassicDummy;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithArray;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithDateTimes;
@@ -25,6 +27,7 @@
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNestedArray;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNullableProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithPhpDoc;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithSyntheticProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithUnionProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithValueTransformerAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\SelfReferencingDummy;
@@ -273,6 +276,13 @@ public function testWriteObjectWithDollarNamedProperties()
         $this->assertWritten('{"$foo":true,"{$foo->bar}":true}', new DummyWithDollarNamedProperties(), Type::object(DummyWithDollarNamedProperties::class));
     }
 
+    public function testWriteObjectWithSyntheticProperty()
+    {
+        $writer = new JsonStreamWriter($this->createMock(ContainerInterface::class), new SyntheticPropertyMetadataLoader(), $this->streamWritersDir);
+
+        $this->assertSame('{"synthetic":true}', (string) $writer->write(new DummyWithSyntheticProperties(), Type::object(DummyWithSyntheticProperties::class)));
+    }
+
     #[DataProvider('throwWhenMaxDepthIsReachedDataProvider')]
     public function testThrowWhenMaxDepthIsReached(Type $type, mixed $data)
     {

src/Symfony/Component/JsonStreamer/Tests/Read/StreamReaderGeneratorTest.php

@@ -22,10 +22,12 @@
 use Symfony\Component\JsonStreamer\Read\StreamReaderGenerator;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Enum\DummyBackedEnum;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Enum\DummyEnum;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Mapping\SyntheticPropertyMetadataLoader;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\ClassicDummy;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNameAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNullableProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithOtherDummies;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithSyntheticProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithUnionProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithValueTransformerAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\ValueTransformer\DivideStringAndCastToIntValueTransformer;
@@ -53,9 +55,9 @@ protected function setUp(): void
     }
 
     #[DataProvider('generatedStreamReaderDataProvider')]
-    public function testGeneratedStreamReader(string $fixture, Type $type)
+    public function testGeneratedStreamReader(string $fixture, Type $type, ?PropertyMetadataLoaderInterface $propertyMetadataLoader = null)
     {
-        $propertyMetadataLoader = new GenericTypePropertyMetadataLoader(
+        $propertyMetadataLoader ??= new GenericTypePropertyMetadataLoader(
             new DateTimeTypePropertyMetadataLoader(new AttributePropertyMetadataLoader(
                 new PropertyMetadataLoader(TypeResolver::create()),
                 new ServiceContainer([
@@ -81,7 +83,7 @@ public function testGeneratedStreamReader(string $fixture, Type $type)
     }
 
     /**
-     * @return iterable<array{0: string, 1: Type}>
+     * @return iterable<array{0: string, 1: Type, 2?: PropertyMetadataLoaderInterface}>
      */
     public static function generatedStreamReaderDataProvider(): iterable
     {
@@ -107,6 +109,7 @@ public static function generatedStreamReaderDataProvider(): iterable
         yield ['object_in_object', Type::object(DummyWithOtherDummies::class)];
         yield ['object_with_nullable_properties', Type::object(DummyWithNullableProperties::class)];
         yield ['object_with_value_transformer', Type::object(DummyWithValueTransformerAttributes::class)];
+        yield ['object_with_synthetic_properties', Type::object(DummyWithSyntheticProperties::class), new SyntheticPropertyMetadataLoader()];
 
         yield ['union', Type::union(Type::int(), Type::list(Type::enum(DummyBackedEnum::class)), Type::object(DummyWithNameAttributes::class))];
         yield ['object_with_union', Type::object(DummyWithUnionProperties::class)];

src/Symfony/Component/JsonStreamer/Tests/Write/StreamWriterGeneratorTest.php

@@ -21,12 +21,14 @@
 use Symfony\Component\JsonStreamer\Mapping\Write\DateTimeTypePropertyMetadataLoader;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Enum\DummyBackedEnum;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Enum\DummyEnum;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Mapping\SyntheticPropertyMetadataLoader;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\ClassicDummy;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithArray;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithDollarNamedProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNameAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithNestedArray;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithOtherDummies;
+use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithSyntheticProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithUnionProperties;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithValueTransformerAttributes;
 use Symfony\Component\JsonStreamer\Tests\Fixtures\Model\SelfReferencingDummy;
@@ -56,9 +58,9 @@ protected function setUp(): void
     }
 
     #[DataProvider('generatedStreamWriterDataProvider')]
-    public function testGeneratedStreamWriter(string $fixture, Type $type)
+    public function testGeneratedStreamWriter(string $fixture, Type $type, ?PropertyMetadataLoaderInterface $propertyMetadataLoader = null)
     {
-        $propertyMetadataLoader = new GenericTypePropertyMetadataLoader(
+        $propertyMetadataLoader ??= new GenericTypePropertyMetadataLoader(
             new DateTimeTypePropertyMetadataLoader(new AttributePropertyMetadataLoader(
                 new PropertyMetadataLoader(TypeResolver::create()),
                 new ServiceContainer([
@@ -79,7 +81,7 @@ public function testGeneratedStreamWriter(string $fixture, Type $type)
     }
 
     /**
-     * @return iterable<array{0: string, 1: Type}>
+     * @return iterable<array{0: string, 1: Type, 2?: PropertyMetadataLoaderInterface}>
      */
     public static function generatedStreamWriterDataProvider(): iterable
     {
@@ -111,6 +113,7 @@ public static function generatedStreamWriterDataProvider(): iterable
         yield ['object_with_value_transformer', Type::object(DummyWithValueTransformerAttributes::class)];
         yield ['self_referencing_object', Type::object(SelfReferencingDummy::class)];
         yield ['object_with_dollar_named_properties', Type::object(DummyWithDollarNamedProperties::class)];
+        yield ['object_with_synthetic_properties', Type::object(DummyWithSyntheticProperties::class), new SyntheticPropertyMetadataLoader()];
 
         yield ['union', Type::union(Type::int(), Type::list(Type::enum(DummyBackedEnum::class)), Type::object(DummyWithNameAttributes::class))];
         yield ['object_with_union', Type::object(DummyWithUnionProperties::class)];

src/Symfony/Component/JsonStreamer/Write/StreamWriterGenerator.php

@@ -133,7 +133,7 @@ private function createDataModel(Type $type, string $accessor, array $options =
             $propertiesNodes = [];
 
             foreach ($propertiesMetadata as $streamedName => $propertyMetadata) {
-                $propertyAccessor = $accessor.'->'.$propertyMetadata->getName();
+                $propertyAccessor = $propertyMetadata->getName() ? $accessor.'->'.$propertyMetadata->getName() : 'null';
 
                 foreach ($propertyMetadata->getNativeToStreamValueTransformer() as $valueTransformer) {
                     if (\is_string($valueTransformer)) {