Add support for @ExceptionHandler inside @RestController

[wtell400]

When creating an @ExceptionHandler in a @RestController, similar to @RestControllerAdvice I expect the OpenAPI documentation to contain the response for this ExceptionHandler. I'm not sure if this is a bug of a missing feature and thus a feature request.

@RestControllerAdvice
public class ExceptionControllerAdvice
{
    // This is generated in OpenAPI documentation
    @ExceptionHandler(CustomException1.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public ErrorMessage handleException1(RuntimeException e)
    {
        return new ErrorMessage(HttpStatus.NOT_FOUND, e.getMessage());
    }
}

@RestController
public class ClassExceptionHandlerController
{
    // This is not generated in OpenAPI documentation
    @ExceptionHandler(CustomException2.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ErrorMessage handleException(RuntimeException e)
    {
        return new ErrorMessage(HttpStatus.BAD_REQUEST, e.getMessage());
    }

    @GetMapping("/classexceptionhandler/1")
    public void test1() {
        throw new CustomException1();
    }

    @GetMapping("/classexceptionhandler/2")
    public void test2() {
        throw new CustomException2();
    }
}

Expected:

• Both 400 (from @RestController) and 404 (from @RestControllerAdvice) as responses of mappings.

Actual:

• Only 404 (from @RestControllerAdvice) as response of mappings.

Using springdoc-openapi 1.4.1. See attached project.
springdoc-bug-classexceptionhandler.zip

[bnasslahsen]

@wtell400,

The support is now added on master, and you can validate it with the latest SNAPHSOT;
It will be available in the next release.