Fix compatibility issues with ESLint 9

[net]

ESLint 9 dropped support for some legacy plugin APIs. This migrates the plugin's rules to support ESLint 9, while staying backwards compatible.

Much of the diff is whitespace changes migrating legacy function rules to the object syntax, so I suggest viewing it with hide whitespace enabled.

Notably, this does not update the plugin to use the new flat config. This plugin will still work with the new flat config, but anyone wanting to use this in a flat config will have to use this compatibility syntax:

import relay from 'eslint-plugin-relay';

export default [
  // ...
  {
    plugins: { relay },
    // Note the default version on npm is a few years out of date, so to use
    // ts-recommended you have to install the latest @main tag via 
    //
    //     npm i --save-dev eslint-plugin-relay@main
    //
    rules: relay.configs['ts-recommended'].rules,
  },
];

If anyone wants to try updating the plugin to work natively with the new flat config, see: https://eslint.org/docs/latest/extend/plugin-migration-flat-config

Partially fixes #156.

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[tyao1]

Thanks for fixing compatibility issues! There are some lint error in the commit, could you take a look?

Run yarn run lint
yarn run v1.22.22
$ eslint eslint-plugin-relay.js src

/home/runner/work/eslint-plugin-relay/eslint-plugin-relay/src/rule-compat-uses-vars.js
  38:[4](https://github.com/relayjs/eslint-plugin-relay/actions/runs/13423081297/job/38121857195?pr=157#step:5:5)4  error  Parsing error: Unexpected token ?

/home/runner/work/eslint-plugin-relay/eslint-plugin-relay/src/rule-generated-flow-types.js
  88:42  error  Parsing error: Unexpected token ?

/home/runner/work/eslint-plugin-relay/eslint-plugin-relay/src/rule-generated-typescript-types.js
  332:44  error  Parsing error: Unexpected token ?

/home/runner/work/eslint-plugin-relay/eslint-plugin-relay/src/rule-graphql-naming.js
  [5](https://github.com/relayjs/eslint-plugin-relay/actions/runs/13423081297/job/38121857195?pr=157#step:5:6)9:54  error  Parsing error: Unexpected token ?

/home/runner/work/eslint-plugin-relay/eslint-plugin-relay/src/rule-graphql-syntax.js
  47:31  error  Parsing error: Unexpected token ?

/home/runner/work/eslint-plugin-relay/eslint-plugin-relay/src/utils.js
  48:48  error  Parsing error: Unexpected token ?

✖ [6](https://github.com/relayjs/eslint-plugin-relay/actions/runs/13423081297/job/38121857195?pr=157#step:5:7) problems (6 errors, 0 warnings)

[net]

@tyao1 I believe those are caused by the version of eslint that this repo itself uses being out of date. I’ll go ahead and update it to the latest if that works for you.

[fbjork]

Would be lovely to see this PR merged!

[net]

@tyao1 I fixed the lint errors by upgrading to ESLint 9. I also fixed all the failing tests.

Unfortunately, there are six flow tests that are still failing that I wasn't able to fix. I believe they're failing due to the original changes for ESLint 9 compatibility.

Since those changes are backwards compatible, I don't believe this PR introduces any regressions for users on older ESLint versions despite those failing tests. Flow users on ESLint 9 may experience the generated-flow-types rule not surfacing errors in a few cases where it should, but that seems preferable to not being able to use the eslint-plugin-relay at all. The tests aren't failing due to runtime errors; the rule just isn't returning errors in a few cases where they're expected.

I commented out the six failing flow tests here: e81285a

I believe this is mergable now :)

[tyao1]

@tyao1 I fixed the lint errors by upgrading to ESLint 9. I also fixed all the failing tests.

Unfortunately, there are six flow tests that are still failing that I wasn't able to fix. I believe they're failing due to the original changes for ESLint 9 compatibility.

Since those changes are backwards compatible, I don't believe this PR introduces any regressions for users on older ESLint versions despite those failing tests. Flow users on ESLint 9 may experience the generated-flow-types rule not surfacing errors in a few cases where it should, but that seems preferable to not being able to use the eslint-plugin-relay at all. The tests aren't failing due to runtime errors; the rule just isn't returning errors in a few cases where they're expected.

I commented out the six failing flow tests here: e81285a

I believe this is mergable now :)

thanks for the fixes. These rules with failing tests might be redundant with the latest flow. We can revisit these failing tests if needed.

Do you have access to merge?

[net]

Looks like the GitHub workflow errored so no release was published to NPM. Guessing it has something to do with actions/setup-node@v2 being pretty out of date—actions/setup-node@v4 is the latest now.

If no one looks into it I might take a look later.

[captbaritone]

Shipped in eslint-plugin-relay@0.0.0-main-e39d0e7f7bfc174041e83f84d14760ca88a2b158 if folks want to try it out and confirm that it works.

[eMerzh]

it works from here, i can remove the fixupPluginRules 👯 :)

thanks

[MTG2000]

Yup, working fine now.

Thanks! 👌