[ObjectMapper] read source metadata before transform

fixes symfony#61027

Author: soyuka

src/Symfony/Component/ObjectMapper/ObjectMapper.php

@@ -72,6 +72,12 @@ public function map(object $source, object|string|null $target = null): object
         }
 
         $mappedTarget = $mappingToObject ? $target : $targetRefl->newInstanceWithoutConstructor();
+
+        if (!$metadata && ($targetMetadata = $this->metadataFactory->create($mappedTarget))) {
+            $metadata = $targetMetadata;
+            $map = $this->getMapTarget($metadata, null, $source, null);
+        }
+
         if ($map && $map->transform) {
             $mappedTarget = $this->applyTransforms($map, $mappedTarget, $source, null);
 

src/Symfony/Component/ObjectMapper/Tests/Fixtures/TargetTransform/SourceEntity.php

@@ -0,0 +1,17 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ObjectMapper\Tests\Fixtures\TargetTransform;
+
+class SourceEntity
+{
+    public string $name;
+}

src/Symfony/Component/ObjectMapper/Tests/Fixtures/TargetTransform/TargetDto.php

@@ -0,0 +1,29 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ObjectMapper\Tests\Fixtures\TargetTransform;
+
+use Symfony\Component\ObjectMapper\Attribute\Map;
+
+#[Map(source: SourceEntity::class, transform: [self::class, 't'])]
+class TargetDto
+{
+    #[Map(if: false)]
+    public bool $transformed;
+    public string $name;
+
+    public static function t(mixed $value, object $source, ?object $target)
+    {
+        $value->transformed = true;
+
+        return $value;
+    }
+}

src/Symfony/Component/ObjectMapper/Tests/ObjectMapperTest.php

@@ -64,6 +64,8 @@
 use Symfony\Component\ObjectMapper\Tests\Fixtures\ServiceLocator\B as ServiceLocatorB;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\ServiceLocator\ConditionCallable;
 use Symfony\Component\ObjectMapper\Tests\Fixtures\ServiceLocator\TransformCallable;
+use Symfony\Component\ObjectMapper\Tests\Fixtures\TargetTransform\SourceEntity;
+use Symfony\Component\ObjectMapper\Tests\Fixtures\TargetTransform\TargetDto as TargetTransformTargetDto;
 use Symfony\Component\PropertyAccess\PropertyAccess;
 
 final class ObjectMapperTest extends TestCase
@@ -447,4 +449,17 @@ public static function validPartialInputProvider(): iterable
 
         yield [$p, $f];
     }
+
+    public function testMapWithSourceTransform()
+    {
+        $source = new SourceEntity();
+        $source->name = 'test';
+
+        $mapper = new ObjectMapper();
+        $target = $mapper->map($source, TargetTransformTargetDto::class);
+
+        $this->assertInstanceOf(TargetTransformTargetDto::class, $target);
+        $this->assertTrue($target->transformed);
+        $this->assertSame('test', $target->name);
+    }
 }