Bug: test:types broken with eslint>=9.31.0

[mureinik]

Environment

Node version: 24.4.1
npm version: 11.4.2
ESLint version: 9.31.0
eslint-plugin-n version: 17.21.0
Operating System: macOS

What rule do you want to report?

The CI process - test:types

Link to Minimal Reproducible Example

npm run test:types

What did you expect to happen?

The CI should pass

Participation

• I am willing to submit a pull request for this issue.

Additional comments

Since eslint@9.31.0 was released, the CI fails:

➜  eslint-plugin-n git:(master) npm run test:types
npm warn using --force Recommended protections disabled.

> eslint-plugin-n@17.21.0 test:types
> tsc --noEmit --emitDeclarationOnly false

lib/rules/no-path-concat.js:201:67 - error TS2339: Property 'getScope' does not exist on type 'PluginRuleContext<{ RuleOptions: unknown[]; }>'.

201                     sourceCode.getScope?.(programNode) ?? context.getScope()
                                                                      ~~~~~~~~

lib/util/eslint-compat.js:20:69 - error TS2339: Property 'getScope' does not exist on type 'RuleContext'.

20     return sourceCode.getScope?.(node || sourceCode.ast) || context.getScope()
                                                                       ~~~~~~~~

lib/util/eslint-compat.js:28:55 - error TS2339: Property 'getAncestors' does not exist on type 'RuleContext'.

28     return sourceCode.getAncestors?.(node) || context.getAncestors()
                                                         ~~~~~~~~~~~~


Found 3 errors in 2 files.

Errors  Files
     1  lib/rules/no-path-concat.js:201
     2  lib/util/eslint-compat.js:20

[mureinik]

The root cause is eslint/eslint#19910 that removed some of eslint's (deprecated?) type declarations. The failures seen above are consistent with the changes in that PR, which was included in eslint@9.31.0.

[aladdin-add]

it's a bugfix to remove the types in eslint - as they have been removed in eslint v9.

We're still using it to support eslint v8 at the same time, and I'm not sure what the best way to do that is, but the easiest way to fix it seems to be to simply ignore it (something like ts-ignore)?

[mureinik]

it's a bugfix to remove the types in eslint - as they have been removed in eslint v9.

We're still using it to support eslint v8 at the same time, and I'm not sure what the best way to do that is, but the easiest way to fix it seems to be to simply ignore it (something like ts-ignore)?

The simplest thing I could think of (as done in #460) was to lock down eslit to 9.30.1, which restores the implicit behavior the master branch had prior to the release of 9.31.0 about two weeks ago.
If you (or any other contributors) think that using ts-ignore is a better idea, I'm game.

[aladdin-add]

yes, please - locking the version would prevent us from testing the latest release. I don’t believe this is what we want.

[mureinik]

@aladdin-add Good point.
I've updated #460 accordingly.