Eloquent Value Object are not casted back when converting models to json.

[rela589n]

• Laravel Version: 7.15.0
• PHP Version: 7.3.7
• Database Driver & Version: 10.3.16-MariaDB

Description:

The problem is that value objects are not casted back when call Client::toJson().
So, for example we have next model:

App\Models\Client {#4028
     id: 7,
     name: "asdf@asdf.com",
     email_verified_at: null,
   }

Accessing name property gives us Name value object:

App\ValueObjects\Name^ {#4027
  #name: "asdf@asdf.com"
}

When we call $client->toJson(), we get empty object instead of primitive value:
{"id":7,"name":{},"email_verified_at":null}

Steps To Reproduce:

Client Eloquent Model:

class Client extends Authenticatable
{
    use Notifiable;

    protected $table = 'users';

    protected $hidden = [
        'password', 'remember_token',
    ];

    protected $casts = [
        'name'     => NameCast::class,
        'password' => PasswordCast::class,
    ];
}

Name Cast:

class NameCast implements CastsAttributes
{
    public function get($model, string $key, $value, $attributes)
    {
        return Name::create($value);
    }

    public function set($model, string $key, $setName, $attributes)
    {
        if (!$setName instanceof Name) {
            throw new \InvalidArgumentException('Parameter $setName must be instance of ' . Name::class);
        }

        return [
            $key => $setName->value()
        ];
    }
}

Name Value Object:

class Name
{
    public const MIN_LENGTH = 2;

    protected $name;

    private function __construct(string $name)
    {
        if (mb_strlen($name) < self::MIN_LENGTH) {
            throw new \InvalidArgumentException('Name must has at least ' . self::MIN_LENGTH . ' characters');
        }

        $this->name = $name;
    }

    public static function create(string $name): Name
    {
        return new static($name);
    }

    public function value()
    {
        return $this->name;
    }
}

[driesvints]

I get the same result and was also a bit surprised at this. I'm suspecting that this is the expected behavior and that you should implement Illuminate\Contracts\Support\Arrayable on your value object. But it would be good to clarify this in the docs.

Gonna wait to see what @taylorotwell says about this.

[taylorotwell]

Objects are expected to implement Arrayable / JsonSerializable to solve this. I thought I documented that but maybe not. If not we can update the documentation.

[driesvints]

I sent in a PR here: laravel/docs#6123