feat: remove legacy eslintrc configuration

[MikeMcC399]

BREAKING CHANGE: Drop legacy configuration support

• closes Drop legacy config support #257

Situation

Since the release of ESLint v9.0.0 on Apr 5, 2024 all mainstream plugins have been able to migrate to offer a flat configuration option. The need to retain support for legacy eslintrc configuration for actively evolving projects has therefore significantly diminished.

The deprecated eslintrc configuration option requires ESLint v8 for CI testing and this version has been in end-of-life status since Oct 5, 2024. This setup is not sustainable in the long term.

Deprecation was already announced in the plugins documentation ESLINTRC-CONFIG.md > Deprecations with [email protected] on Oct 30, 2024.

This means that users have had more than one year to become acquainted with flat configurations, and have had more than 6 months deprecation notice specifically for this plugin.

Change

• The default configuration eslint-plugin-cypress now resolves to the flat configuration instead of to the legacy configuration

• The explicit flat configuration eslint-plugin-cypress/flat continues to resolve to the flat configuration. Since it is however now the default, it becomes redundant to explictly add /flat. It therefore becomes deprecated and documentation states that it is planned for removal in a future major version.

• The legacy.js export which provided deprecated legacy rules and cypress/recommended is removed

• The directory tests-legacy containing rule testing for eslintrc configurations is removed. Corresponding Jest tests and configs are also removed.

• In the circle.yml workflow

  • tests run in the CircleCI convenience image cimg/node:22.16.0 corresponding to the active Node.js LTS version
  • the test-v8 job is removed
  • configurations for the test-project are updated to use eslint-plugin-cypress instead of eslint-plugin-cypress/flat
  • a default-deprecation configuration is added to test eslint-plugin-cypress/flat

• .node-version and .nvmrc are updated to Node.js 22.16.0.

• Rules in lib/flat.js are alphabetically sorted for better maintainability.

• Documentation is updated:

  • README
  • FLAT-CONFIG
  • ESLINTRC-CONFIG
  • CONTRIBUTING

• globals is updated from 15.15.0 to 16.2.0 (current latest)

• semantic-release is updated from 24.2.3 to 24.2.5 (current latest)

[cypress-app-bot]

• Create a Draft Pull Request if your PR is not ready for review. Mark the PR as Ready for Review when you're ready for a Cypress team member to review the PR.

[MikeMcC399]

ci/circleci: test-v8 needs to be removed as a required job, since it has been removed from the circle.yml workflow

[jennifer-shehane]

I do so love deleting code. Breaking change semantic commit looks good. Changes look good. I removed the v8 status check. Good with deprecation of /flat

[jennifer-shehane]

🎉 This PR is included in version 5.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[MikeMcC399]

@jennifer-shehane

I do so love deleting code.

😁 The legacy code wasn't maintainable anymore, so it was definitely good to be able to delete it. I did check on Discord with the ESLint folks about the general timing of removing support for legacy configs and they also thought it was OK now.

Breaking change semantic commit looks good. Changes look good. I removed the v8 status check. Good with deprecation of /flat

Thanks for removing the status check!

If you are able to edit out "simplify import text explanation" from the release notes, that would be clearer, as this was just an afterthought to the README document edit and shouldn't be highlighted.

[jennifer-shehane]

@MikeMcC399 I updated the release log: https://github.com/cypress-io/eslint-plugin-cypress/releases/tag/v5.0.0

[MikeMcC399]

@jennifer-shehane

I updated the release log: https://github.com/cypress-io/eslint-plugin-cypress/releases/tag/v5.0.0

Thanks! That looks much better now!