Clone on lazy ghost does loose data

[Nilz11]

Bug Report

Q	A
BC Break	yes/no
Version	2.13

Summary

Issue seems to be the same as in doctrine/orm:

doctrine/orm#11787

If you call clone on an unitialized proxy loaded via @ReferenceOne, it does not initialize properly and data is gone.

Current behavior

$child = $parent->getChild(); // Proxy of $child. Empty. 
$clonedParent = clone $child;

$clonedParent->getName(); // Name if empty, even though it was set in database

How to reproduce

Workaround is to force load the document by accessing property:

$parent->getChild(); // Proxy of $child. Empty. 
$parent->getChild()->getName(); // Force orm to load Proxy.
$parent->getChild(); // Now a fully loaded Proxy;

$clonedParent = clone $parent;
$clonedParent->getChild(); // Proxy of $child. Fully loaded.

Expected behavior

I would expect the proxy to load / initialize properly on calling clone or throw an error.

I couldnt find a usable workaround except forcing it by accessing a different property first. I dont understand the logic here deep enough.

[GromNaN]

I wrote the following test that fails with both lazy proxy implementations; with the following error:

Error: Cannot access uninitialized non-nullable property Doctrine\ODM\MongoDB\Tests\Functional\Ticket\GH2851Child::$name by reference

Unit Test Code

<?php

declare(strict_types=1);

namespace Doctrine\ODM\MongoDB\Tests\Functional\Ticket;

use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;
use Doctrine\ODM\MongoDB\Tests\BaseTestCase;

class GH2851Test extends BaseTestCase
{
    public function testOverridingFieldsType(): void
    {
        $parent        = new GH2851Parent();
        $child         = new GH2851Child();
        $child->name   = 'child name';
        $parent->child = $child;

        $this->dm->persist($parent);
        $this->dm->persist($child);
        $this->dm->flush();
        $this->dm->clear();

        $fetchedParent = $this->dm->find(GH2851Parent::class, $parent->id);
        $clonedChild = clone $fetchedParent->child;
        $this->assertSame('child name', $clonedChild->name);
    }
}

#[ODM\Document]
class GH2851Parent
{
    #[ODM\Id]
    public string $id;

    /** @var int|string|null */
    #[ODM\ReferenceOne(targetDocument: GH2851Child::class, cascade: ['persist'])]
    public GH2851Child $child;
}

#[ODM\Document]
class GH2851Child
{
    #[ODM\Id]
    public string $id;

    #[ODM\Field(type: 'string')]
    public string $name;
}

That proves the lazy object is not loaded when the object is cloned.

[GromNaN]

There is no issue using the native lazy objects introduced in #2840