Take MediaType set in pre-match filter into when returning Response

Fixes: quarkusio#41097

Author: geoand

independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/serialization/DynamicEntityWriter.java

@@ -41,8 +41,15 @@ public void write(ResteasyReactiveRequestContext context, Object entity) throws
             ServerHttpRequest vertxRequest = context.serverRequest();
             // first check and see if the resource method defined a media type and try to use it
             if ((context.getTarget() != null) && (context.getTarget().getProduces() != null)) {
-                MediaType negotiatedMediaType = context.getTarget().getProduces()
-                        .negotiateProduces(vertxRequest.getRequestHeader(HttpHeaders.ACCEPT)).getKey();
+                MediaType negotiatedMediaType = null;
+                List<String> accepts = context.getHttpHeaders().getRequestHeader(HttpHeaders.ACCEPT);
+                for (String accept : accepts) {
+                    negotiatedMediaType = context.getTarget().getProduces().negotiateProduces(accept).getKey();
+                    if (negotiatedMediaType != null) {
+                        break;
+                    }
+                }
+
                 List<MessageBodyWriter<?>> writersList = serialisers.findWriters(null, entity.getClass(), negotiatedMediaType,
                         RuntimeType.SERVER);
                 if (!writersList.isEmpty()) {

independent-projects/resteasy-reactive/server/vertx/src/test/java/org/jboss/resteasy/reactive/server/vertx/test/matching/PreMatchAcceptInHeaderTest.java

@@ -20,6 +20,7 @@
 import jakarta.ws.rs.core.HttpHeaders;
 import jakarta.ws.rs.core.MediaType;
 import jakarta.ws.rs.core.MultivaluedMap;
+import jakarta.ws.rs.core.Response;
 import jakarta.ws.rs.ext.Provider;
 
 import org.jboss.resteasy.reactive.server.spi.ResteasyReactiveResourceInfo;
@@ -123,6 +124,37 @@ void entityTextWithAcceptToTextInFilter() {
                 .body(equalTo("text"));
     }
 
+    @Test
+    void responseEntityJsonWithoutAcceptToTextInFilter() {
+        given().accept("application/json")
+                .when()
+                .get("test/response")
+                .then()
+                .statusCode(200)
+                .body(containsString("\"text\""));
+    }
+
+    @Test
+    void responseEntityTextWithoutAcceptToTextInFilter() {
+        given().accept("text/plain")
+                .when()
+                .get("test/response")
+                .then()
+                .statusCode(200)
+                .body(equalTo("text"));
+    }
+
+    @Test
+    void responseEntityTextWithAcceptToTextInFilter() {
+        given().accept("application/json")
+                .header("x-set-accept-to-text", "true")
+                .when()
+                .get("test/response")
+                .then()
+                .statusCode(200)
+                .body(equalTo("text"));
+    }
+
     @Path("/test")
     public static class Resource {
 
@@ -152,6 +184,13 @@ public String html() {
         public Entity entity() {
             return new Entity("text");
         }
+
+        @GET
+        @Path("response")
+        @Produces({ MediaType.TEXT_PLAIN, MediaType.TEXT_HTML })
+        public Response response() {
+            return Response.ok(new Entity("text")).build();
+        }
     }
 
     public record Entity(String value) {