Support ESLint 9

[MikeMcC399]

Issue

This plugin should support usage with ESLint v9.0.0 announcement dated Apr 5, 2024.

See also the Migration Guide to v9.x.

The repo test running jest fails with ESlint 9.

Versions

eslint@9.0.0
eslint-plugin-cypress@2.15.2
Ubuntu 22.04.4 LTS
Node.js 20.12.2 LTS

Steps to reproduce

Ubuntu 22.04.4 LTS, Node.js 20.12.1 LTS

git clone https://github.com/cypress-io/eslint-plugin-cypress
cd eslint-plugin-cypress
npm install eslint@9 -D
npm test

Logs

Test log

The full log is not shown here. It starts with:

$ npm test

> eslint-plugin-cypress@0.0.0-development test
> jest

 FAIL  tests/lib/rules/no-unnecessary-waiting.js
  ● no-unnecessary-waiting › valid › foo.wait(10)

    ConfigError: ESLint configuration in rule-tester is invalid: Config (unnamed): Key "parserOptions": This appears to be in eslintrc format rather than flat config format.

      at rethrowConfigError (node_modules/@humanwhocodes/config-array/api.js:225:8)
      at node_modules/@humanwhocodes/config-array/api.js:1018:5
          at Array.reduce (<anonymous>)
      at FlatConfigArray.getConfig (node_modules/@humanwhocodes/config-array/api.js:1014:39)
      at runRuleForItem (node_modules/eslint/lib/rule-tester/rule-tester.js:793:25)
      at testValidTemplate (node_modules/eslint/lib/rule-tester/rule-tester.js:908:28)
      at Object.<anonymous> (node_modules/eslint/lib/rule-tester/rule-tester.js:1258:33)

and ends with:

 PASS  tests/config.js

Test Suites: 9 failed, 1 passed, 10 total
Tests:       130 failed, 3 passed, 133 total
Snapshots:   0 total
Time:        1.651 s, estimated 3 s
Ran all test suites.

Related

• Upgrade to new ESLint Flat configuration files #146
• Eslint 8 deprecated rules context: planned failure Eslint 9 #154

Edit: Updated for latest changes to repo Apr 18, 2024

[MikeMcC399]

Unfortunately the title of this issue and the errors it describes are not in sync.

• PR docs: add document for FlatCompat use #201 provides documentation about using the plugin in FlatCompat mode. Using this as a basis it should be possible to open up the plugin also for usage with ESLint 9.x very soon.

• The test errors described are due to breaking changes in the v9 > RuleTester. The rules themselves have already been worked on to make them compatible with ESLint 9.x. That was done in PR fix: convert deprecated context calls #182.

• The set of tests need to be reworked to deal with the changes described in Testing rules with flat config and the RuleTester class and FlatRuleTester is now RuleTester. Once this is done, I expect to close this issue.

• The single outstanding item will be Upgrade to new ESLint Flat configuration files #146. Due to the FlatCompat mode, this is not a gating factor to use the plugin under ESLint 9.x, although it is definitely a desirable enhancement.

[MikeMcC399]

• ESLint v9 is now supported by this plugin in release v3.2.0
• See README for configuration details.

Enjoy 😄 !

[MikeMcC399]

The repo https://github.com/cypress-io/cypress-example-kitchensink demonstrates eslint-plugin-cypress@3.2.0 running under eslint@9.2.0.