feat: eslint 9 support

[brettz9]

Adds ESLint 9 support.

Attempts to dogfood with flat config and ESLint 9 use internally, but a few plugins could not be upgraded (See the config file).

I also upgraded a number of dependencies/devDeps and adjusted tests accordingly.

This still should need a closer look and testing (I couldn't get the spec:e2e script working though that could be a slow connection where I am), but I thought I'd try to get the ball rolling with this draft.

[dargmuesli]

Are those changes backwards compatible? If not, the merged changes should include an exclamation mark likefeat!: eslint 9 support to make sure the release has a proper version.

[brettz9]

Are those changes backwards compatible? If not, the merged changes should include an exclamation mark likefeat!: eslint 9 support to make sure the release has a proper version.

Ah yes, thanks for the reminder. It is currently breaking, with globals now requiring Node 18 (and I should update engines as well), though I could revert those changes if such a switch is not desired, as otherwise the changes should not be breaking. I would personally think it is reasonable to up the minimum version and use the latest version.

[brettz9]

I've updated to indicate it is a breaking change, but the PR title doesn't accept the exclamation mark, so I just did it within the commit.

[amilajack]

@brettz9 is this PR ready for review? it's still in draft

[brettz9]

Yes, it's ready for review. I just put it as a draft because I didn't want to convey it was ready for a quick merge, as someone should at least confirm the spec:e2e tests (I have a spotty connection where I am so it may be that which is preventing me from completing and reviewing those tests.)

[amilajack]

Published this to next tag. Please test and I can push to latest tag

npm i eslint-plugin-compat@next

[dargmuesli]

Seems to be working for me!
Just keep in mind to check if it's breaking for eslint v8 users and publish as v6 maybe, not v5.1.0.

[brettz9]

It should still work with ESLint 8 (and whatever earlier versions were still working before the changes--the peerDependencies go back a ways). But it is a breaking change due to the Node version bump.

Works for me also in both ESLint 8 and ESLint 9.

[xconverge]

I do see this with yarn (4.3.1), but will ignore it. I just figured I would mention it...

 eslint is listed by your project with version 9.6.0 (pe4bd0), which doesn't satisfy what eslint-plugin-compat and other dependencies request (^8.0.0).

maybe missing a || ^9.0.0 somewhere? hmm it looks right in this MR...

lock file looks good too..not sure what is going on

-"eslint-plugin-compat@npm:5.0.0":
-  version: 5.0.0
-  resolution: "eslint-plugin-compat@npm:5.0.0"
+"eslint-plugin-compat@npm:5.1.0-0":
+  version: 5.1.0-0
+  resolution: "eslint-plugin-compat@npm:5.1.0-0"
   dependencies:
-    "@mdn/browser-compat-data": "npm:^5.5.19"
+    "@mdn/browser-compat-data": "npm:^5.5.35"
     ast-metadata-inferer: "npm:^0.8.0"
-    browserslist: "npm:^4.23.0"
-    caniuse-lite: "npm:^1.0.30001605"
+    browserslist: "npm:^4.23.1"
+    caniuse-lite: "npm:^1.0.30001639"
     find-up: "npm:^5.0.0"
-    globals: "npm:^13.24.0"
+    globals: "npm:^15.7.0"
     lodash.memoize: "npm:^4.1.2"
-    semver: "npm:^7.6.0"
+    semver: "npm:^7.6.2"
   peerDependencies:
-    eslint: ^4.0.0 || ^5.0.0 || ^6.0.0 || ^7.0.0 || ^8.0.0
-  checksum: 10c0/07c0a90e601dffec0ea31c2c85c32679ab13238c030936d25fa57433e8c37566428249ee4fee6f98a107d8fc90214000ac4e6d4eaf646bd34bb96248bc5112e3
+    eslint: ^4.0.0 || ^5.0.0 || ^6.0.0 || ^7.0.0 || ^8.0.0 || ^9.0.0
+  checksum: 10c0/183183bb39e10ea0c3a489679a43b8c351f915457000330f57954a49b6d4a647237bd0b3a4621b4cf6a3f3c90e62a159cdf28f0d4716238321dc3919676a7ed0
   languageName: node
   linkType: hard

[amilajack]

Published 6.0.0 🥳