feature symfony#61006 [JsonStreamer] Provide current object to value transformers (mtarld)

This PR was merged into the 7.4 branch.

Discussion
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[JsonStreamer] Provide current object to value transformers

| Q             | A
| ------------- | ---
| Branch?       | 7.4
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Issues        |
| License       | MIT

A new attempt to symfony#59281.

As discussed with `@soyuka`, it is really important to have access to the current object during stream writing.
Without that, it'll for example be impossible for API Platform to generate resource IRIs (https://github.com/api-platform/core/blob/main/src/Metadata/IriConverterInterface.php#L46).

This PR makes is available in value transformers' `$context` under the `_current_object` key.

Commits
-------

e9dcd42 [JsonStreamer] Allow to access current object when writing

Author: nicolas-grekas

src/Symfony/Component/JsonStreamer/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Remove `nikic/php-parser` dependency
+ * Add `_current_object` to the context passed to value transformers during write operations
 
 7.3
 ---

src/Symfony/Component/JsonStreamer/Tests/Fixtures/stream_writer/object_with_value_transformer.php

@@ -190,6 +190,42 @@ public function testWriteObjectWithValueTransformer()
         );
     }
 
+    public function testValueTransformerHasAccessToCurrentObject()
+    {
+        $dummy = new DummyWithValueTransformerAttributes();
+        $dummy->id = 10;
+        $dummy->active = true;
+
+        $this->assertWritten(
+            '{"id":"20","active":"true","name":"dummy","range":"10..20"}',
+            $dummy,
+            Type::object(DummyWithValueTransformerAttributes::class),
+            options: ['scale' => 1],
+            valueTransformers: [
+                BooleanToStringValueTransformer::class => new class($this) implements ValueTransformerInterface {
+                    public function __construct(
+                        private JsonStreamWriterTest $test,
+                    ) {
+                    }
+
+                    public function transform(mixed $value, array $options = []): mixed
+                    {
+                        $this->test->assertArrayHasKey('_current_object', $options);
+                        $this->test->assertInstanceof(DummyWithValueTransformerAttributes::class, $options['_current_object']);
+
+                        return (new BooleanToStringValueTransformer())->transform($value, $options);
+                    }
+
+                    public static function getStreamValueType(): Type
+                    {
+                        return BooleanToStringValueTransformer::getStreamValueType();
+                    }
+                },
+                DoubleIntAndCastToStringValueTransformer::class => new DoubleIntAndCastToStringValueTransformer(),
+            ],
+        );
+    }
+
     public function testWriteObjectWithPhpDoc()
     {
         $dummy = new DummyWithPhpDoc();

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

@@ -23,7 +23,10 @@
 interface ValueTransformerInterface
 {
     /**
-     * @param array<string, mixed> $options
+     * @param array{
+     *     _current_object?: object, // When writing stream: the object holding the current property
+     *     ...<string, mixed>,
+     * } $options
      */
     public function transform(mixed $value, array $options = []): mixed;
 

src/Symfony/Component/JsonStreamer/ValueTransformer/ValueTransformerInterface.php

@@ -138,7 +138,7 @@ private function createDataModel(Type $type, string $accessor, array $options =
                 foreach ($propertyMetadata->getNativeToStreamValueTransformer() as $valueTransformer) {
                     if (\is_string($valueTransformer)) {
                         $valueTransformerServiceAccessor = "\$valueTransformers->get('$valueTransformer')";
-                        $propertyAccessor = "{$valueTransformerServiceAccessor}->transform($propertyAccessor, \$options)";
+                        $propertyAccessor = "{$valueTransformerServiceAccessor}->transform($propertyAccessor, ['_current_object' => $accessor] + \$options)";
 
                         continue;
                     }
@@ -152,7 +152,7 @@ private function createDataModel(Type $type, string $accessor, array $options =
                     $functionName = !$functionReflection->getClosureCalledClass()
                         ? $functionReflection->getName()
                         : \sprintf('%s::%s', $functionReflection->getClosureCalledClass()->getName(), $functionReflection->getName());
-                    $arguments = $functionReflection->isUserDefined() ? "$propertyAccessor, \$options" : $propertyAccessor;
+                    $arguments = $functionReflection->isUserDefined() ? "$propertyAccessor, ['_current_object' => $accessor] + \$options" : $propertyAccessor;
 
                     $propertyAccessor = "$functionName($arguments)";
                 }