[Laravel] IRIs are not denormalized to Eloquent models before FormRequest validation

[shahzaibtariqbutt]

API Platform version(s) affected: 4.1.20

Description
When using API Platform with Laravel and FormRequest validation, relation fields sent as IRIs (e.g. "/areas/{id}") are not denormalized to Eloquent models before the validation runs.
Instead, FormRequest receives the raw string. This differs from Symfony’s behavior, where relation IRIs are denormalized into Doctrine entities before Symfony Validator runs.

How to reproduce

1. Have an API Platform Laravel resource with a relation to Area.
2. Send JSON: { "area": "/areas/01abc123..." }
3. In the FormRequest: dd($this->input('area'));
4. Outputs "/areas/01abc123..."

Example Code

#[ApiResource(
    operations: [
        new Post(
            rules: StoreSlotRequest::class,
            denormalizationContext: [
                'groups' => [
                    'slot:write'
                ],
            ],
        )
     ]
)]
#[ApiProperty(property: 'area',
    serialize: new Groups(['slot:write']
))]
class Slot extends Model{}

class StoreSlotRequest extends FormRequest
{
  public function rules(): array
    {
       dd($this->input('area')); // "/areas/01abc123..."
    }
}

[soyuka]

Indeed, we can not transform to an object before validation with form request because Laravel validation system works best on an array, this array should be the raw json body.

I suggested a way of getting the object at soyuka@624cb1b#diff-c7658cf2d0066b48c2709e085a740ae6cfbe649d077a44d7ec5aac45d5391771R39-R43 :

namespace Workbench\App\Http\Requests;

use Workbench\App\Models\Area;
use ApiPlatform\Metadata\IriConverterInterface;
use Illuminate\Foundation\Http\FormRequest;
use Illuminate\Support\Facades\App;

class StoreSlotRequest extends FormRequest
{
    public static ?Area $receivedArea = null;

    public function authorize(): bool
    {
        return true;
    }

    public function rules(): array
    {
        $iriConverter = App::get(IriConverterInterface::class);

        return [
            'name' => ['required', 'string', 'max:255'],
            'area' => [
                'required',
                'string',
                function (string $attribute, mixed $value, \Closure $fail) use ($iriConverter): void {
                    if (!(self::$receivedArea = $iriConverter->getResourceFromIri($value))) {
                        $fail("The {$attribute} is invalid.");
                    }
                },
            ],
        ];
    }
}