Support backed enums in #[MapQueryParameter]

[kells64000]

Symfony version(s) affected

6.3.1

Description

If you use #[MapQueryParameter] and type the property with Enum, the QueryParameterValueResolver only accepts scalars.

If I change the resolver to BackedEnumValueResolver, it only looks at the attributes and not the query.
The enum is never resolved and the value is null.

How to reproduce

Controller:

#[Route('/', name: 'test_param_enum']
public function testParameterAction(#[MapQueryParameter] Status $status = null) 
{
        
}

OR

#[Route('/', name: 'test_param_enum']
public function testParameterAction(#[MapQueryParameter(resolver: BackedEnumValueResolver::class)] Status $status = null) 
{
        
}

Enum:

enum Status: string
{
    case New = 'new';
    case Published = 'published';
}

Query:

/?status=new

Possible Solution

1. Allow enum in QueryParameterValueResolver
2. Check for query parameters in BackedEnumValueResolver
3. Add a new resolver QueryParameterBackedEnumValueResolver
4. ???

Additional Context

No response

[andersmateusz]

@kells64000
Why do u consider this a bug? In documentation (https://symfony.com/blog/new-in-symfony-6-3-query-parameters-mapper) there is no non-scalar value usage example. According to source code Symfony\Component\HttpKernel\Controller\ArgumentResolver\BackedEnumValueResolver can resolve only Symfony\Component\HttpFoundation\Request::attributes. Considering another Symfony\Component\HttpKernel\ControllerValueResolverInterface implementation i.e. Symfony\Component\HttpKernel\Controller\ArgumentResolver\DateTimeValueResolver there is also only support for attributes:

 if (!is_a($argument->getType(), \DateTimeInterface::class, true) || !$request->attributes->has($argument->getName())) {
     return [];
 }

So I would consider this as feature, not as a bug. The question is whether this feature is needed or not.

[derrabus]

I agree that this is a new feature. And it makes total sense to support enums here. Do you want to wirk on a PR?

[andersmateusz]

@derrabus
Sure, I can work on this. I propose to change issue name to '#[MapQueryParameter] Add support for \BackedEnum'.

[kells64000]

It was a bug for me because why can I use any resolver if none of them looks at the query parameters?

[andersmateusz]

It was a bug for me because why can I use any resolver if none of them looks at the query parameters?

Only QueryParameterValueResolver supports resolving query parameters, besides there are many implementations of ArgumentResolverInterface, but I agree that it is misleading that you can use any ArgumentResolverInterface as argument for #[MapQueryParameter]. I guess authors aimed to allow for custom query parameter value resolver. There are annotations that suggest that you can use only QueryParameterValueResolver for resolving params, although it would be good to make typing more precise e.i. by using intersection types how i described in my PR #51004.