Avoid 406 Not Acceptable for error pages

[bclozel]

Given a Spring MVC Controller like:

@RestController
public class TestController {
	@GetMapping(path = "/test", produces = "text/plain")
	public String test() {
		throw new ExpectedException();
	}

	@ResponseStatus(value = HttpStatus.BAD_REQUEST, reason = "Expected!")
	static class ExpectedException extends RuntimeException {

	}
}

When clients send requests to the "/test" endpoint and the Accept: text/plain request header, the error response rendered by Spring Boot's ErrorController has an empty body and a "406 Not Acceptable" HTTP status. Although the client is not able to read the response body, we should not hide the original HTTP response status as it might give important information about the error.

This happens because the ErrorController tries to render the error map with the requested media type, which is text/plain. Since it is not possible to serialize the error map in that format, the original HTTP status response is overridden and the client gets a 406 instead.

In these cases, we should not write the response body and instead use the orignal HTTP response status with an empty response body.

We've seen instances of this problem in #13163 and spring-projects/spring-framework#23421

[snicoll]

@bclozel would it be possible to backport this one?

[bclozel]

@snicoll I'm not sure. This is improving the error handling support but it changes the existing behavior which is not strictly a bug. So I'm wondering if developers are expecting this somehow in tests, or (in a strange way) relying on this.

[rstoyanchev]

I think there is a good case for a backport. It seems unlikely that an application can do something meaningful that would depend on the current behavior. A test might be fail somewhere but that's an easy change.

[rstoyanchev]

It would be really useful to have this one in 2.2.x. I keep running into issues where the original status is obscured.

[wilkinsona]

It was back ported in 2f78c72 which was in 2.2.3. Assuming that you're seeing the problem with 2.2.3 or later, it sounds like we need to investigate to learn why you're still seeing a problem. @rstoyanchev is there a sample project somewhere that we can look at?

[rstoyanchev]

Ah yes indeed it was, and it is working as expected, my bad. Cheers!

[mojtaba-ghasemi]

in spring boot: imagine that we want to return in web service method same as:

ResponseEntity.status(HttpStatus.CREATED)
        .body(myObject);

myObject class need to use @Data annotation from Lombok package

@Data
public class myClass{
...
}