Backed enum serialization

[theofidry]

From #1608, BackedEnum are resolved as follows:

if (is_a($value, \BackedEnum::class)) {
  return $value->value;
}

I find this serialization a bit strange. Indeed if you consider the following object:

class UrlType {
  const WEBSITE = 'website';
  const OTHER = 'other';
}

with the following GraphQL configuration (using OverblogGraphQLBundle):

UrlType:
    type: enum
    config:
        values:
            WEBSITE: { value: website }
            OTHER: { value: other }

And the following class:

class Url {
  function __construct(
    public string $type,
  ) {}
}

Then with the object new Url(type: UrlType::WEBSITE), the returned JSON will be something along the lines of:

{
  "url": {
    "type": "WEBSITE"
  }
}

Note how it is the GraphQL UrlType name that is used to return the value. If you submit type: WEBSITE in GraphQL, then the value serialized to PHP will be 'website'.

Now the issue: make UrlType into a backed string enum instead:

enum UrlType: string {
  case WEBSITE = 'website';
  case OTHER = 'other';
}

Then the JSON response will now be:

{
  "url": {
    "type": "website"
  }
}

I do not know what is correct from the GraphQL spec perspective, but surely having such different behaviour when transforming a pseudo-enum into a backed enum seems incorrect?

[spawnia]

Good catch, fixed with https://github.com/webonyx/graphql-php/releases/tag/v15.14.3. Please consider sponsoring.