[New] add eslint 9 support

[michaelfaith]

This change adds support for eslint v9. All three example projects have been updated to use the latest eslint, and the root package's dev and peer deps have been updated.

In order to make this work with both v9 and older versions, I had to update the parser options helper to adjust the config passed into the RuleTester. It was also necessary update jest to a newer version, in order to resolve eslint's use of node:fs/promises.

Note: the removed test cases are exact duplicates of other tests. v9 fails tests when its determined to be an exact duplicate.

Closes: #978

[ljharb]

we can't upgrade jest, because jest 24 is the last version that supports node 6.

[michaelfaith]

Hmm. Ok, but jest 24 isn't able to resolve node:fs/promises which eslint uses (so we hit this when importing RuleTester from eslint). I could map node:fs/promises to something like fs-extra using jest's moduleNameMapper? So the project is never going higher than jest 24?

[ljharb]

at some point we'll have a breaking change that drops older eslints/nodes, but i'm more likely to bail on jest entirely and use something less frictiony regardless.

can you map node:fs/promises to fs/promises, instead? the node: prefix is pretty useless.

[michaelfaith]

After a few iterations, I got it working. I ended up having to map several built in node modules, as well as a couple of esm entry points of eslint packages, I also had to add a polyfill for structuredClone, which eslint uses as part of RuleTester and was added in node 17.

[michaelfaith]

Everything's green now, if you want to take another look when you have the time. It may be worth considering dynamically installing a newer jest for v9 and removing all of those workarounds (in the same way each eslint version is being installed), but I'll leave that to you.

[socket-security]

New and removed dependencies detected. Learn more about Socket for GitHub ↗︎

Package	New capabilities	Transitives	Size	Publisher
npm/@eslint/js@9.9.1	None	0	14.2 kB	eslintbot
npm/core-js@3.38.1	None	0	1.24 MB	zloirock
npm/eslint@9.9.1	environment Transitive: eval, filesystem, shell, unsafe	+88	9.91 MB	eslintbot
npm/globals@15.9.0	None	0	174 kB	sindresorhus

View full report↗︎

[codecov]

Codecov Report

Attention: Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.

Project coverage is 98.73%. Comparing base (a08fbcc) to head (1231f61).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
__tests__/__util__/parserOptionsMapper.js	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1009      +/-   ##
==========================================
- Coverage   99.03%   98.73%   -0.30%     
==========================================
  Files         107      107              
  Lines        1660     1666       +6     
  Branches      588      591       +3     
==========================================
+ Hits         1644     1645       +1     
- Misses         16       21       +5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ljharb]

Seems good!

[iamtomcat]

When is this going out? Currently just using it from the repository directly.

[ljharb]

@iamtomcat i'm not sure how you'd do that in a practical sense, since we have a build process. It's only been 2 days - I'd suggest not using it at all until it's published.

[iamtomcat]

Hey @ljharb I appreciate you getting the change out, I wasn't trying to rush you, just wanted to get a time frame was all.

Thanks again.

[ljharb]

it's now released; v6.10.0.

[ruiaraujo012]

@ljharb I think something is missing, there's no v6.10.0 release, there is a tag but not a release.

[ljharb]

oh thanks, i always forget github releases (which don't matter; only npm matters)

[ruiaraujo012]

Oh, you're right, I didn't check npm 🙈 sorry.