Multiple Sulu entity inheritance

[bober888]

Q	A
Sulu Version	2.5.10
PHP Version	8.1
DB Version	PostgreSQL 10.12
Browser Version	--

Actual Behavior + Steps to Reproduce

The problem occurs when overloading entities multiple times. For example, we create a new entity Base\User, which inherits from Sulu\User. We override the email column in the .orm mapping using XML with the <attribute-override> attribute. Then we create another entity App\User, which inherits from Base/User:

<?php

declare(strict_types=1);

namespace App;

class User extends \Base\User
{
}

<?php

declare(strict_types=1);

namespace Base;

class User extends \Sulu\Bundle\SecurityBundle\Entity\User
{
}

Base\User mapping:

<?xml version="1.0" encoding="utf-8"?>
<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
                  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                  xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping http://doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
    <mapped-superclass name="Base\User" table="se_users">
            <attribute-overrides>
                <attribute-override name="email">
                    <field unique="false" length="255" nullable="true"/>
                </attribute-override>
             <attribute-overrides>
    </mapped-superclass>
</doctrine-mapping>

Upon running doctrine:scheme:validate, we encounter the error "Invalid field override named 'email' for class 'Base\User'". The issue arises in the class Sulu\Component\Persistence\EventSubscriber\ORM\MetadataSubscriber, which takes parents (Base\User then Sulu\User) from App\User and sets metadata for App\User associations. The error occurs at line 105: $configuration->getMetadataDriverImpl()->loadMetadataForClass($parent, $parentMetadata);, during the initialization of metadata for Base\User (in the loadMetadataForClass method) because it does not consider that the entity may have its own parents.

Expected Behavior + Possible Solutions

The expected behavior is that the method should initialize metadata for all parent entities and gradually set it for all children. A correct implementation can be found, for example, in the Doctrine\Persistence\Mapping\AbstractClassMetadataFactory class in the getAllMetadata() method.

[bober888]

As possible solution:
subcriber.patch

Patched on one project, where this problem was detected. With this solution works fine

[alexander-schranz]

We don't have yet any experience with using a mapped super class between of them or using attribute-override, but think it should be possible with some refactoring. I remeber that we used a normaly entity in between with them adding new properties where there no problem.

Still I want to mention that we can never guarante backwards compatibility for models which are changed via attribute-override, this may can crash if Sulu depends on some cases like this attribute being unique or a specific length for an index.

If you want to contribute a patch, give it a try, but it will require some special test setup so we can guarantee it will work in future.