Wrong exception handling for @RequestParam of type boolean

[mzatko]

If an invalid value is passed to @RequestParam of type boolean, an IllegalArgumentException is thrown, which is indistinguishable from other IllegalArgumentException exceptions.
This then leads to a 500 InternalServerError, which is clearly incorrect, as it is a clear example of a 400(BadRequest) error.

example

@GetMapping
ResponseEntity<Void> getException(@RequestParam(name = "bool", defaultValue = "false", required = false) boolean bool) {
   ...
}

then pasing GET http://server:port/?bool=dummy

causes 500 internalServerError

[Gautam-aman]

Hi, I’d like to work on this issue.

I plan to add a failing MockMvc test demonstrating that an invalid boolean
@RequestParam currently results in a 500 response, and then update the
argument resolution logic so it correctly returns 400 Bad Request.

Please let me know if there’s any preferred approach before I open a PR.

[bclozel]

@mzatko can you share a minimal sample? I cannot reproduce the behavior you are describing. Please find my sample attached.

illegalarg.zip

[bclozel]

@Gautam-aman it looks like you went ahead without confirming the problem first. I'll close the other issue and the 2 PRs as we're not sure we need anything at the moment.

[mzatko]

@bclozel I had "deeper" look at the problem, it looks like it is @ExceptionHandler problem. In fact, there is @MethodArgumentTypeMismatchException thrown however I had no @ExceptionHandler(MethodArgumentTypeMismatchException.class) defined so exception was handled by @ExceptionHandler(IllegalArgumentException.class) as it is a cause of @MethodArgumentTypeMismatchException. @MethodArgumentTypeMismatchException is cut out completely from "causes chain" and ignored as if never existed. It is really strange behavior of @ExceptionHanler
I am closing this issue.