Symfony version(s) affected

7.4

Description

Hi there,

I'm not sure, if it's really a bug or I'm using it wrong.
Into an Controller I'll get as JSON an object of arrays of objects. If not understand what I mean, an example is in the additional context, controller and DTO is in how to reproduce.
Sending an request to this, I'll get an exception: Symfony\Component\ObjectMapper\ObjectMapper::map(): Argument #1 ($source) must be of type object, array given, called in /var/www/html/project/vendor/symfony/object-mapper/Transform/MapCollection.php on line 39
Of course, I understand the mapper tries to map an array to an ArrayCollection of Entites. But how should this work, what was the programmer thinking?

How to reproduce

class ManySpecsDTO
{
    public function __construct(

        #[Map(target: "spec_1", transform: new MapCollection())]
        /** @var Spec1[] */
        public readonly array $spec_1,
        
        #[Map(target: "spec_2", transform: new MapCollection())]
        /** @var Spec2[] */
        public readonly array $spec_2,
    )
    {
        
    }
}

public function controllerMethod(
#[MapRequestPayload] ManySpecsDTO $manySpecsDTO)
{

}

Possible Solution

I wish to get two behaviors:

• In the RequestPayload-DTO an array of DTOs (without mapper?)
• in the Mapper-Target-Object an ArrayCollection of the request objects

With the documentation I don't get how this should work.

Additional Context

JSON Object of Request:

{
  spec_1: [
    {
      spec_1_id: 1,
      spec_1_name: "Test"
    },
    {
      spec_1_id: 2,
      spec_1_name: "Test 2"
    }
  ],
spec_2: [
    {
      spec_2_id: 1,
      spec_2_name: "Test"
    },
    {
      spec_2_id: 2,
      spec_2_name: "Test 2"
    }
  ],
}

Could someone help here please?

Thank you