Enable WARN logging with DefaultHandlerExceptionResolver

[philwebb]

Currently if an exception such as MissingServletRequestParameterException is thrown no stack-trace is logged. It would be useful to provide an option to add them.

Something like this in EnableWebMvcConfiguration:

        @Override
        protected void configureHandlerExceptionResolvers(
                List<HandlerExceptionResolver> exceptionResolvers) {
            addDefaultHandlerExceptionResolvers(exceptionResolvers);
            for (HandlerExceptionResolver resolver : exceptionResolvers) {
                if (resolver instanceof DefaultHandlerExceptionResolver) {
                    ((DefaultHandlerExceptionResolver) resolver)
                            .setWarnLogCategory(DefaultHandlerExceptionResolver.class
                                    .getName());
                }
            }
        }

I'm not sure if this should be on or off by default.

[philwebb]

@wilkinsona @dsyer Any thoughts about this? Trying to debug #2162 highlighted the problem. Not sure if we should enable by default because the logs could get pretty full just by people posting incomplete data.

[wilkinsona]

Tricky one. On the one hand, it could be used as a form of DoS attack if you managed to flood the logs with exception messages. On the other hand, it'd make problem diagnosis easier.

I could be convinced either way but perhaps we should err toward secure by default and default to off?

[philwebb]

Moving to 1.3. Could be another good candidate to enable during development but not in production.

[chrylis]

I'm not familiar enough with the internals of the MVC chain post-controller to say whether mine is a duplicate, but they're semantically related. This one seems to be dealing with resolving controller arguments, and mine is about exceptions thrown after the controller has returned an argument during JSON/XML serialization.