Hibernate validator responses with wrong Content-Type header when working in reactive mode

[fedinskiy]

Describe the bug

I have two Resteasy Reactive endpoints, both have @Digits annotation from Hibernate Validator. One of the endpoint doesn't have any @Produces annotations, another has @Produces(MediaType.TEXT_PLAIN). When querying both with invalid values, both return message with header Content-Type=application/json(1) and with body, which is not json(2).

When quarkus-resteasy-reactive is replaced with quarkus-resteasy, both headers contain "text/plain".

Expected behavior

Validation messages should have "Content-Type" header, which faithfully describes content of body.
If endpoint has @Produces annotation, then content and headers of validation messages should conform to it.
If endpoint has no @Produces annotation, then validation messages should return text, to mirror the behavior of classic implementation.

Actual behavior

Both endpoints return responses with header Content-Type=application/json and bodies like that:

ViolationReport{title='Constraint Violation', status=400, violations=[Violation{field='validate.id', message='numeric value out of bounds'}]}

for comparison, proper json endpoints return bodies, like this:

{
    "title": "Constraint Violation",
    "status": 400,
    "violations": [
        {
            "field": "validate.id",
            "message": "numeric value out of bounds"
        }
    ]
}

How to Reproduce?

1. Clone: git clone git@github.com:fedinskiy/reproducer.git -b reproducer/validator-json-header
2. Run tests mvn clean verify -Preactive
3. Run mvn clean verify -Pclassic to verify, that classic version works as expected

Output of uname -a or ver

2.12.3.Final

Output of java -version

11.0.16 temurin

GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.12.3.Final

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

Apache Maven 3.8.6 (84538c9988a25aec085021c365c560670ad80f63)

Additional information

No response

[quarkus-bot]

/cc @gsmet, @yrodiere

[gsmet]

@geoand looks more like a RESTEasy Reactive issue to me. The OP provided a reproducer above.

I think there are two issues here: the content type and the content itself, which should probably be made more readable (not sure how RESTEasy Classic handles text plain validation).

[geoand]

I'll have a look next week.

Thanks for the heads up

[geoand]

#28343 takes care of it