Eslint 9 fails with legacy config .eslintrc

[MikeMcC399]

Issue

Linting with an Eslint deprecated Configuration File fails when using the environment variable setting ESLINT_USE_FLAT_CONFIG = false and the repository being tested uses the configuration file

.eslintrc.

Versions

[email protected]
[email protected]
Ubuntu 22.04.4 LTS
Node.js 20.12.1 LTS

Steps to reproduce

Ubuntu 22.04.4 LTS, Node.js 20.12.1 LTS

git clone --branch test/eslint-9-cypress https://github.com/MikeMcC399/cypress-example-kitchensink
cd cypress-example-kitchensink
npm ci
export ESLINT_USE_FLAT_CONFIG=false
npm run lint

Logs

$ npm run lint

> [email protected] lint
> eslint --fix cypress app/assets/js/scripts.js


Oops! Something went wrong! :(

ESLint: 9.0.0

TypeError: context.getAncestors is not a function
Occurred while linting /home/mike/github/tmp/cypress-example-kitchensink/cypress/e2e/1-getting-started/todo.cy.js:20
Rule: "cypress/no-async-tests"
    at Identifier (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint-plugin-cypress/lib/rules/no-async-tests.js:32:37)
    at ruleErrorHandler (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/linter.js:1145:48)
    at /home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/safe-emitter.js:45:58
    at Array.forEach (<anonymous>)
    at Object.emit (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/safe-emitter.js:45:38)
    at NodeEventGenerator.applySelector (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/node-event-generator.js:297:26)
    at NodeEventGenerator.applySelectors (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/node-event-generator.js:326:22)
    at NodeEventGenerator.enterNode (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/node-event-generator.js:340:14)
    at runRules (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/linter.js:1184:40)
    at Linter._verifyWithoutProcessors (/home/mike/github/tmp/cypress-example-kitchensink/node_modules/eslint/lib/linter/linter.js:1453:31)
(node:5779) ESLintRCWarning: You are using an eslintrc configuration file, which is deprecated and support will be removed in v10.0.0. Please migrate to an eslint.config.js file. See https://eslint.org/docs/latest/use/configure/migration-guide for details.
(Use `node --trace-warnings ...` to show where the warning was created)

Related

• Peer dependency failure using npm ci on repo source #153
• Upgrade to new ESLint Flat configuration files #146
• Eslint 8 deprecated rules context: planned failure Eslint 9 #154
• Support ESLint 9 #155

References

• Eslint > Configuration Files (Deprecated)

[brettz9]

Besides the flat files, ESLint 9 also changed some APIs. In this case, as can be seen in the error message, it is that context.getAncestors has been dropped. See https://eslint.org/blog/2023/09/preparing-custom-rules-eslint-v9/#context.getancestors()

[MikeMcC399]

Thanks @brettz9 !

• I was struggling a little about how to report the different migration issues. I've noted this also in Eslint 8 deprecated rules context: planned failure Eslint 9 #154.

• There is a similar issue also for the related mocha plugin Rules fail with ESLint 9.0.0 - context.getScope is not a function lo1tuma/eslint-plugin-mocha#352 Edit: the mocha issue is fixed now.

[MikeMcC399]

• There is a great tracking list on 📈 Tracking: Flat Config support eslint/eslint#18093 showing compatibility progress.

[MikeMcC399]

The plugin should prevent installation with ESLint 9.x until it is compatible with this version.

[MikeMcC399]

• See also related issue Outdated peerDependencies eslint >= 3.2.1 #175

[MikeMcC399]

• This issue is resolved by PR feat: support eslint v7 & v8 instead of ">= 3.2.1" #176 which restricts the use of the plugin to ESLint v7 and v8

• The enhancement request to support ESLint v9 is logged under issue Support ESLint 9 #155

• The underlying API deprecations are planned to be resolved by PR fix: convert deprecated context calls #182