@FeignClient with decode404 set doesn't return Optional.empty on 404

For a method which returns something of type Optional, when decode404 is set to true and you receive a 2xx response, then the type is correctly wrapped into an Optional. If you receive a 404 response, then null is returned rather than Optional.empty().

I would expect Optional.empty() to be returned if 404 is returned and decode404 is set.

Example:

@FeignClient(decode404 = true)
public interface SecondService {
    @RequestMapping(method = RequestMethod.GET, value = "/foo/{id}")
    Optional<Foo> getFoo(@PathVariable("id") String id);
}