`"Key "0" in object with ArrayAccess of class does not exist` error after change of computer

Question

I changed my computer and tried to import my project to my new computer.

I use Symfony (6 on my old PC and 7 on my new one). I used Doctrine to recreate the database locally before importing all data. In the project a Book has Authors and an Editor.

Why do I get error "Key "0" in object with ArrayAccess of class "Doctrine\ORM\PersistentCollection" does not exist.?

Even though it loads all the data, the Collection of Authors is empty, and for the Editor, I have:

-lazyObjectState: Symfony\Component\VarExporter\Internal\LazyObjectState {#1038 ▼
        +status: UNINITIALIZED_FULL

My relations are mapped. I don't have this problem on my old PC.

Entities:

<?php

namespace App\Entity;

use App\Repository\LibrisRepository;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\DBAL\Types\Types;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity(repositoryClass: LibrisRepository::class)]
#[ORM\Table("exlibris")]
class Libris implements \JsonSerializable
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    [...]

    #[ORM\ManyToOne(inversedBy: 'libris')]
    #[ORM\JoinColumn(nullable: false)]
    private ?Editeur $editeur = null;

    #[ORM\ManyToMany(targetEntity: Auteur::class, inversedBy: 'libris')]
    private Collection $auteurs;

    #[ORM\Column(length: 100, nullable: true)]
    private ?string $xl_img = null;

    #[ORM\Column(length: 50)]
    private ?string $xl_livre = null; /*nom du Libris*/

    #[ORM\OneToMany(mappedBy: 'libris', targetEntity: BDConcern::class)]
    private Collection $bdConcernes;

<?php

namespace App\Entity;

use App\Repository\AuteurRepository;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity(repositoryClass: AuteurRepository::class)]
class Auteur implements \JsonSerializable
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 30)]
    private ?string $nom = null;

    #[ORM\Column(length: 30, nullable: true)]
    private ?string $prenom = null;

    #[ORM\ManyToMany(targetEntity: Libris::class, mappedBy: 'auteurs')]
    private Collection $libris;

Got the error here :

    {% for l in listL %}
            [...]
                {{ l.auteurs[0].prenom }} {{ l.auteurs[0].nom }}</p>
            [...]
    {% endfor %}

dd of listL

AccueilController:

$listL = $libRepo->findAccRecent();

libRepo :

public function findAccRecent(): array
   {
        $etats = [1, 2];

    return $this->createQueryBuilder('l')
           ->andWhere('l.xl_etat IN (:etat)')
           ->setParameter('etat', $etats)
           ->orderBy('l.xl_date', 'DESC')
           ->setMaxResults(18)
           ->getQuery()
           ->getResult();
   }

Answer 1

Found out that not adding all the joins in the repository was the problem. Don't know why it worked before.