Nyc should prefer .nycrc config over the package.json nyc stanza

[AndrewFinlay]

Expected Behavior

Nyc should prefer config found in an explicitly specified .nycrc file to config specified in the package.json nyc stanza. This allows you to override existing config using the cli.

Observed Behavior

Nyc prefers config from the nyc stanza in package.json

Bonus Points! Code (or Repository) that Reproduces Issue

Run nyc from the root of this repo with a .nycrc file specified via --nycrc-path, the set of exclude files is taken from package.json rather than .nycrc.

Forensic Information

Operating System: macOS High Sierra
Environment Information:
node v8.11.1
npm v6.1.0

This looks like it's an order of operations issue in "config-util.js", where .pkgConf('nyc', cwd) is applied to the yargs object before we load config from file and apply it to the argv object.

[coreyfarrell]

I'm leaning towards you being correct, but I'm not sure how to solve this. In any case this will be a breaking change and v13 is already frozen. This will give us time to think about edge cases related to this.

I haven't tried to reproduce your issue but one question: when nyc takes excludes from package.json rather than .nycrc, do both configs contain an exclude option?

[AndrewFinlay]

I found this one when making changes to nyc to fix the issues I was having with excluding files during instrumentation, see #890 and #893. I'd cloned nyc onto my local machine and was running from the nyc root directory, passing in my .nycrc file location as an option.

That .nycrc file had an exclude section, but it was never used, it picked up the exclude section from nyc's package.json instead, leaving me a little puzzled as to why none of my changes had any effect. So yes, both nyc's package.json nyc stanza and my .nycrc file had an exclude section.

I did take a shot at fixing this within nyc, and it's possible but it will need a bit of refinement, and to be honest I think the issue may really be in the way yargs handles multiple option sets.

Edit: Related to #388

[AndrewFinlay]

Bump, stale bot

[AndrewFinlay]

bump

[JaKXz]

@AndrewFinlay I've just pinned this issue for stale bot. Thanks!

[coreyfarrell]

@AndrewFinlay I suspect you might be correct about this potentially being a yargs issue. Any chance you have time to try putting together an isolation and reporting to the yargs repo?

[AndrewFinlay]

Sure thing, but it's not priority #1 at the moment so it may be a week or so.

[coreyfarrell]

I suspect this will be fixed when we start using @istanbuljs/load-nyc-config to load configuration. In this setup we'll stop using yargs.pkgConf and just provide a load config callback.

[AndrewFinlay]

Thought I'd check over this one again and it all seems to work properly now.

I've put together a demo repo here with tap snapshot test that might be useful in nyc.

[coreyfarrell]

I think we might have testing for this covered in @istanbuljs/load-nyc-config, if not that's probably where it belongs.

[AndrewFinlay]

Ok, I'll take a look over there and submit a PR if necessary.
BTW, thanks for your work on this through v15, it's nice to be able to work on nyc without the little roadblocks.