Fix generic handling of ParamConverter

Fixes: #35774
(cherry picked from commit c3479a0)

extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/simple/GenericsParamConverterTest.java

@@ -0,0 +1,109 @@
+package io.quarkus.resteasy.reactive.server.test.simple;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.CoreMatchers.is;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Type;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.QueryParam;
+import jakarta.ws.rs.ext.ParamConverter;
+import jakarta.ws.rs.ext.ParamConverterProvider;
+import jakarta.ws.rs.ext.Provider;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+
+public class GenericsParamConverterTest {
+
+    @RegisterExtension
+    static QuarkusUnitTest test = new QuarkusUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addClasses(TestEnum.class, Wrapper.class,
+                            WrapperParamConverterProvider.class, WrapperParamConverterProvider.WrapperParamConverter.class,
+                            TestResource.class));
+
+    @Test
+    public void wrapper() {
+        given()
+                .when().get("/test/single?wrapper=ACTIVE")
+                .then()
+                .statusCode(200)
+                .body(is("ACTIVE"));
+    }
+
+    @Test
+    public void wrapperList() {
+        given()
+                .when().get("/test/list?wrapperList=INACTIVE&wrapperList=ACTIVE")
+                .then()
+                .statusCode(200)
+                .body(is("INACTIVE,ACTIVE"));
+    }
+
+    @Path("/test")
+    public static class TestResource {
+
+        @GET
+        @Path("/list")
+        public String list(@QueryParam("wrapperList") final List<Wrapper<TestEnum>> wrapperList) {
+            return wrapperList.stream().map(w -> w.getValue().name()).collect(Collectors.joining(","));
+        }
+
+        @GET
+        @Path("/single")
+        public String single(@QueryParam("wrapper") final Wrapper<TestEnum> wrapper) {
+            return wrapper.getValue().toString();
+        }
+    }
+
+    public enum TestEnum {
+        ACTIVE,
+        INACTIVE
+    }
+
+    public static class Wrapper<E extends Enum<E>> {
+        private final E value;
+
+        public Wrapper(final E value) {
+            this.value = value;
+        }
+
+        public E getValue() {
+            return value;
+        }
+    }
+
+    @Provider
+    public static class WrapperParamConverterProvider implements ParamConverterProvider {
+
+        @Override
+        @SuppressWarnings("unchecked")
+        public <T> ParamConverter<T> getConverter(final Class<T> rawType, final Type genericType,
+                final Annotation[] annotations) {
+            if (Wrapper.class.isAssignableFrom(rawType)) {
+                return (ParamConverter<T>) new WrapperParamConverter();
+            }
+            return null;
+        }
+
+        public static class WrapperParamConverter implements ParamConverter<Wrapper<?>> {
+
+            @Override
+            public Wrapper<?> fromString(String value) {
+                return new Wrapper<>(Enum.valueOf(TestEnum.class, value));
+            }
+
+            @Override
+            public String toString(Wrapper<?> wrapper) {
+                return wrapper != null ? wrapper.getValue().toString() : null;
+            }
+        }
+    }
+}

independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/startup/RuntimeResourceDeployment.java

@@ -527,6 +527,8 @@ private static void smartInitParameterConverter(int i, ParameterConverter quarku
                     Type genericType = genericArguments[0];
                     if (genericType instanceof Class) {
                         genericTypeClassName = ((Class<?>) genericType).getName();
+                    } else if (genericType instanceof ParameterizedType) {
+                        genericTypeClassName = ((ParameterizedType) genericType).getRawType().getTypeName();
                     } else if (genericType instanceof WildcardType) {
                         WildcardType genericTypeWildcardType = (WildcardType) genericType;
                         Type[] upperBounds = genericTypeWildcardType.getUpperBounds();