Add option to fail on warning when json error found

[wyardley]

Tell us more.

JSON formatting errors, like an extra comma, will throw a warning (both in the issue dashboard and in the Mend dashboard),

However, currently, even with --strict, renovate-config-validator won't fail that, even if the filename is .json vs .json5.

% RENOVATE_CONFIG_FILE=default.json LOG_LEVEL=debug npx -p renovate@39 renovate-config-validator --strict
 INFO: Validating renovate.json
DEBUG: Checking for config file in default.json
 WARN: File contents are invalid JSON but parse using JSON5. Support for this will be removed in a future release so please change to a support .json5 file name or ensure correct JSON syntax.
       "context": "default.json"
 INFO: Validating default.json
 INFO: Config validated successfully

I don't know if the --strict flag should barf on such errors (IMO, that would be ideal, though maybe breaking), but either way, it would be nice to have a way to force the command to exit non-0 on this kind of warning, either with --strict or with a new flag (--strict-json? --fail-on-warnings?).

I can (and did) add some basic JSON validation separately that will probably catch most such issues (I used the new fork of jsonlint).

[rarkins]

I would be happy for the --strict mode to error if this WARN is present, although I'm not sure how easy that is to achieve

[viceice]

pass the filename as CLI arg instead of env, then it should fail as expected

[wyardley]

I see that's documented now; I'd always used the env var because IIRC at one point that was the only way to set the filename (can't find the reference, so could be remembering wrong).

That said, unless I'm missing something, I see the same behavior (the program exiting 0) if I add an extra trailing coma to one line when using the filename as a positional argument, whether I use one file or more than one:

% npx renovate-config-validator --strict default.json
 WARN: File contents are invalid JSON but parse using JSON5. Support for this will be removed in a future release so please change to a support .json5 file name or ensure correct JSON syntax.
       "context": "default.json"
 INFO: Validating default.json
 INFO: Config validated successfully
% echo $?
0
% pnpm check

> @xyz/renovate-config@0.0.1 check /Users/william/git/renovate-config
> renovate-config-validator --strict default.json renovate.json

 WARN: File contents are invalid JSON but parse using JSON5. Support for this will be removed in a future release so please change to a support .json5 file name or ensure correct JSON syntax.
       "context": "default.json"
 INFO: Validating default.json
 INFO: Validating renovate.json
 INFO: Config validated successfully
% echo $?
0

(Side note: I did find the docs on passing filename(s) as positional arguments, but it would be super nice if renovate-config-generator had a --help / -h and / or help flag or argument; if this is something you're interested in, I could see if it would be hard to add that)