Symfony version(s) affected

7.3.7

Description

It should be trivially possible to call return $this->json(null) in a controller, however the result of this varies depending whether the serializer service is present. If it is, the output is null, as expected. However, if it is not, the result is {}, and moreover, there is no clear way to "trick" it into somehow outputting null, since internally null is replaced with ArrayObject which explains why we get {} output instead.

How to reproduce

#[Route('/foo')]
final class Foo extends AbstractController
{
    #[Route(methods: ['GET'])]
    public function get(): Response
    {
        return $this->json(null);
    }
}

Possible Solution

The behaviour is normalized by installing the serializer component, but this should not be necessary to get sane behaviour.

Edit: actually it is possible to trick it by doing the following:

    public function get(): Response
    {
        $json = null;

        return $json ? $this->json($json) : new JsonResponse('null', json: true);
    }

This is definitely not an intuitive pattern, though.

Additional Context

No response