PersistProcessor::handleLazyObjectRelations() crashes on uninitialized typed properties

[marius-swfy]

API Platform version(s) affected

4.2.15 (introduced by #7521)

Description

PersistProcessor::handleLazyObjectRelations() iterates all entity properties via ReflectionProperty::getValue() without first checking ReflectionProperty::isInitialized(). This causes a fatal error for typed properties that are only set during Doctrine @PrePersist lifecycle callbacks, since handleLazyObjectRelations() runs before EntityManager::persist().

The issue only affects operations where $operation->canMap() returns true (i.e. ObjectMapper-enabled resources).

How to reproduce

Given a simple entity with typed properties initialized via @PrePersist:

#[ORM\Entity]
#[ORM\HasLifecycleCallbacks]
#[Map(target: BookResource::class)]
class Book
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    public int $id;

    #[ORM\Column(length: 255)]
    public string $title;

    #[ORM\Column(length: 50)]
    public string $status;

    #[ORM\Column]
    public int $version;

    #[ORM\Column(type: Types::DATETIME_IMMUTABLE)]
    public DateTimeInterface $createdAt;

    #[ORM\PrePersist]
    public function initializeDefaults(): void
    {
        $this->status = 'draft';
        $this->version = 1;
        $this->createdAt = new DateTimeImmutable();
    }
}

And an API resource using ObjectMapper:

#[ApiResource(
    shortName: 'books',
    operations: [new Post()],
    stateOptions: new Options(entityClass: Book::class),
)]
#[Map(target: Book::class)]
final class BookResource
{
    #[ApiProperty(identifier: true)]
    public ?int $id = null;

    #[Assert\NotBlank]
    public ?string $title = null;
}

Sending a POST request:

{
    "data": {
        "type": "books",
        "attributes": {
            "title": "My Book"
        }
    }
}

Results in:

Typed property Book::$status must not be accessed before initialization

Stack trace:

PersistProcessor.php:171  ReflectionProperty->getValue()
PersistProcessor.php:107  PersistProcessor->handleLazyObjectRelations()

Possible fix

Add an isInitialized() check before accessing the property value in handleLazyObjectRelations():

 foreach ($reflectionProperties as $propertyName => $reflectionProperty) {
     if ($classMetadata->isIdentifier($propertyName)) {
         continue;
     }

+    if (!$reflectionProperty->isInitialized($data)) {
+        continue;
+    }
+
     $value = $reflectionProperty->getValue($data);

     if (!\is_object($value)) {
         continue;
     }

Since the method's purpose is to find lazy-loaded object relations, skipping uninitialized properties is safe — they cannot contain a lazy proxy object.

Additional Context

This pattern of typed properties without defaults + @PrePersist initialization is common and well-documented in Doctrine. The issue is specifically caused by handleLazyObjectRelations() running at line 107 (before $manager->persist($data) at line 111), so @PrePersist callbacks have not yet fired.