Property promotion not working correctly with associations/proxies

[delolmo]

Bug Report

Q	A
BC Break	no
Version	2.17.1

Summary

I opened this #10456 in the past, hoping that it had been fixed in #10385, but I still keep getting the same error.

Given that associations are loaded through proxies, when using constructor promotion in entities, PHP will throw an error when trying to access a property of the proxy object.

Current behavior

The stated above.

How to reproduce

Given these entities (i.e.):

use Doctrine\ORM\Mapping as ORM;
use Ramsey\UuidInterface;

final class User 
{
      public function __construct(
            #[ORM\Id]
            #[ORM\Column(type: 'uuid_binary')]
            public UuidInterface $id,
            #[ORM\Column(type: 'string', unique: true)
            public string $username,
      ){
      }
}

final class Group
{
      public function __construct(
            #[ORM\Id]
            #[ORM\Column(type: 'uuid_binary')]
            public UuidInterface $id,
            #[ORM\Column(type: 'string', unique: true)
            public string $name,
      ){
      }
}

final readonly class Member
{
      public function __construct(
            #[ORM\Id]
            #[ORM\Column(type: 'uuid_binary')]
            public UuidInterface $id,
            #[ORM\ManyToOne(targetEntity: User::class)
            public User $user,
            #[ORM\ManyToOne(targetEntity: Group::class)
            public Group $group,
      ){
      }
}

One would expect this code to work:

$membersRepo = $entityManager->getRepository(Member::class);
$allMembers = $membersRepo->findAll();

foreach ($allMembers as $member) {
        print_r([$member->user->username, $member->group->name]);
}

But the following error is thrown:

PHP Fatal error:  Uncaught Error: Typed property User::$username must not be accessed before initialization in (...)

Expected behavior

If possible, no error should be thrown and properties should be initialized when trying to access the proxy object.

[delolmo]

Just to continue with the example, this actually works (although it comes as no surprise):

$membersRepo = $entityManager->getRepository(Member::class);
$allMembers = $membersRepo->findAll();

foreach ($allMembers as $member) {
        $entityManager->refresh($user);
        $entityManager->refresh($group);
        print_r([$member->user->username, $member->group->name]);
}