Remove warnings when using JSON formatter

[kalkov]

Hi, while parsing the json from json_formatter I get warnings like this :

  Warning: unrecognized cop Output found in

Which breaks the parsing. Don't you think it's good idea to put them in the json?

[yujinakayama]

I guess you are using --format json without --out somefile (so the JSON data will be outputted to the STDOUT) and the problem is that config validation warning is also outputted to the STDOUT.

I think the warning should be outputted to STDERR so that your JSON parser need to just take care of STDOUT.

[kalkov]

You are right, I'm not outputting to a file. It will be nice to have warnings in the JSON itself.

[yujinakayama]

I think there are some technical issues with storing warnings in JSON and actually I wonder if warnings really should be in JSON. So for now, I'll change the warning to be outputted to STDERR.

[kalkov]

Thanks