Memory Overflow at Doctrine Module with related entities

まず persistEntity と grabEntityFromRepository を使用する機能テストから始め、次に Doctrine モジュールが oneToMany 関係を持つエンティティをどのように処理するかを調べます。TestGroup と TestUser のケースをコントローラーの動作と比較します。関連エンティティが再帰的な出力やメモリオーバーフローを発生させなくなれば完了です。

If an entity is on the 1 side of a 1:n relationship (i.e. it has oneToMany), and I handle it with the Doctrine Module, the object gets infinitely large, thereby causing a PHP memory overflow.

Details

I've set up these two entities:

AppBundle\Entity\TestGroup:
    type: entity
    table: test_group

    id:
        id:
            type: integer
            generator:
                strategy: IDENTITY
              
    fields:
        name:
            type: string
            length: 50
            nullable: true

    oneToMany:
        test_user:
            targetEntity: TestUser
            mappedBy: test_group

AppBundle\Entity\TestUser:
    type: entity
    table: test_user

    id:
        id:
            type: integer
            generator:
                strategy: IDENTITY
              
    fields:
        group_id:
            type: integer
            nullable: true
        name:
            type: string
            length: 50
            nullable: true

    manyToOne:
        test_group:
            targetEntity:
            inversedBy: test_user
            joinColumn:
                name: group_id
                referencedColumnName: id

Now I run this functional test:

public function tryMemoryLeak (FunctionalTester $I)
{
    $group = new \AppBundle\Entity\TestGroup();
    var_dump($group);
    $I->persistEntity($group);
    die;
    var_dump($group);
}

Result: The output from var_dump is normal; and the entity exists in the database. But as soon as I remove die; the bug occurs: I get endless (i.e. hundreds or thousands of lines) output in the console. The same happens if I fetch the entity from the database with $I->grabEntityFromRepository.
This explains what I initially observed: If I try to pass the object to some function, I get a memory overflow crash from PHP.

I've tried it with SQLite and PostgreSQL.

If I do the same with the TestUser entity, everything is normal. So I'm figuring it has something to do with the oneToMany setting.

And if I do it in a controller, everything is fine too - so I'm figuring there's no error in the entities.

Setup

• Codeception version: 2.3.5
• PHP Version: 7.1
• Operating System: Windows 10