RestEasy Reactive warns when the endpoint returns JSON as String

[sberyozkin]

Describe the bug

It is a minor one, I've been experimenting with Oidc Proxy (I need to experiment with OpenAI plugins) - this is a Quarkus JAX-RS endpoint which is presented as an OIDC provider which is implemented by delegating OIDC requests to the real provider such as Keycloak. For example, it returns a JSON containing various tokens and some other properties - it does not need to convert it to a bean, it is simply:

@Produces("application/json")
@GET
public String getJsonWebKeySet() {
}

I have 2 such methods and 2 warnings are generated, for example:

2024-01-04 17:26:24,362 WARN  [io.qua.res.rea.ser.dep.QuarkusServerEndpointIndexer] (build-74) Quarkus detected the use of JSON in JAX-RS method 'org.acme.security.openid.connect.plugin.OidcProxy#jwks' but no JSON extension has been added. Consider adding 'quarkus-resteasy-reactive-jackson' (recommended) or 'quarkus-resteasy-reactive-jsonb'.

The methods still work as expected without adding these extensions.

Expected behavior

Do not issue warning if the return type is String as it will be covered without having to add 'quarkus-resteasy-reactive-jackson' (or 'quarkus-resteasy-reactive-jsonb')

Actual behavior

No response

How to Reproduce?

No response

Output of uname -a or ver

No response

Output of java -version

No response

Quarkus version or git rev

No response

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

No response

[quarkus-bot]

/cc @FroMage (resteasy-reactive), @geoand (resteasy-reactive), @stuartwdouglas (resteasy-reactive)