RESTEasy Reactive: issues with char parameter

[FroMage]

Describe the bug

When I have an endpoint with a char parameter, native-image doesn't work:

Error: com.oracle.graal.pointsto.constraints.UnresolvedElementException: Discovered unresolved method during parsing: java.lang.Character.valueOf(java.lang.String). To diagnose the issue you can use the --allow-incomplete-classpath option. The missing method is then reported at run time when it is accessed the first time.
Trace: 
	at parsing io.quarkus.generated.char$quarkusrestparamConverter$.convert(Unknown Source)
Call path from entry point to io.quarkus.generated.char$quarkusrestparamConverter$.convert(Object): 
	at io.quarkus.generated.char$quarkusrestparamConverter$.convert(Unknown Source)
	at org.jboss.resteasy.reactive.server.core.parameters.converters.RuntimeResolvedConverter.convert(RuntimeResolvedConverter.java:23)
	at org.jboss.resteasy.reactive.server.handlers.ParameterHandler.handleResult(ParameterHandler.java:92)
	at org.jboss.resteasy.reactive.server.handlers.ParameterHandler.handle(ParameterHandler.java:55)
	at org.jboss.resteasy.reactive.server.handlers.ParameterHandler.handle(ParameterHandler.java:15)
	at org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext.run(AbstractResteasyReactiveContext.java:141)
	at java.lang.Thread.run(Thread.java:829)
	at com.oracle.svm.core.thread.JavaThreads.threadStartRoutine(JavaThreads.java:597)
	at com.oracle.svm.core.posix.thread.PosixJavaThreads.pthreadStartRoutine(PosixJavaThreads.java:194)
	at com.oracle.svm.core.code.IsolateEnterStub.PosixJavaThreads_pthreadStartRoutine_e1f4a8c0039f8337338252cd8734f63a79b5e3df(generated:0)

This is due to https://github.com/quarkusio/quarkus/blob/main/independent-projects/resteasy-reactive/server/processor/src/main/java/org/jboss/resteasy/reactive/server/processor/generation/converters/GeneratedConverterIndexerExtension.java because Character.valueOf(String) doesn't exist.

If you don't compile natively, endpoints with a char parameter return a 404 because some converter is needed:

package io.quarkiverse.renarde.util;

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.ws.rs.ext.ParamConverter;
import javax.ws.rs.ext.ParamConverterProvider;
import javax.ws.rs.ext.Provider;

@Provider
public class MyParamConverters implements ParamConverterProvider {

    public static class CharacterParamConverter implements ParamConverter<Character> {

        @Override
        public Character fromString(String value) {
            if (StringUtils.isEmpty(value))
                return null;
            if (value.length() != 1)
                throw new RuntimeException("Invalid character: " + value);
            return value.charAt(0);
        }

        @Override
        public String toString(Character value) {
            if (value == null)
                return null;
            return value.toString();
        }
    }

    @Override
    public <T> ParamConverter<T> getConverter(Class<T> rawType, Type genericType, Annotation[] annotations) {
        if (rawType == Character.class || rawType == char.class)
            return (ParamConverter<T>) new CharacterParamConverter();
        return null;
    }

}

I don't think this converter should be required, so it's probably a bug.

Expected behavior

No response

Actual behavior

No response

How to Reproduce?

No response

Output of uname -a or ver

No response

Output of java -version

No response

GraalVM version (if different from Java)

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 @geoand, @stuartwdouglas

[geoand]

I'll have a look, thanks

[gastaldi]

Here is a test case that reproduces the issue:

package org.jboss.resteasy.reactive.server.vertx.test.simple;

import org.jboss.resteasy.reactive.server.vertx.test.framework.ResteasyReactiveUnitTest;
import org.jboss.shrinkwrap.api.ShrinkWrap;
import org.jboss.shrinkwrap.api.spec.JavaArchive;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.RegisterExtension;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;

import static io.restassured.RestAssured.when;
import static org.hamcrest.Matchers.equalTo;

public class ParamConverterTest {

    @RegisterExtension
    static ResteasyReactiveUnitTest test = new ResteasyReactiveUnitTest()
            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
                    .addClasses(EchoResource.class));

    @Test
    public void charParam() {
        when().get("/echo/character?param=a")
                .then()
                    .statusCode(200)
                    .body(equalTo("a"));
    }

    @Path("echo")
    public static class EchoResource {

        @Path("character")
        @GET
        public String echoChar(@QueryParam("param") char param) {
            return "" + param;
        }
    }

}

[geoand]

char as a type does not make a tremendous amount of sense, but I opened #24549 in any case