[@rollup/plugin-eslint] New flat config `eslint.config.js` is not recognized

[chkosoptim]

• Rollup Plugin Name: @rollup/plugin-eslint
• Rollup Plugin Version: 9.0.5
• Rollup Version: 4.14.3
• Operating System (or Browser): Windows 10
• Node Version: 20.12.2
• Link to reproduction: https://replit.com/@christiankoch2/rollup-eslint-config-not-found

Expected Behavior

The plugin should recognize and work with the new flat config (default since ESLint 9.0.0) eslint.config.js.

Actual Behavior

Running npx rollup --config yields:

[!] (plugin eslint) Error: No ESLint configuration found in <PATH>\src.
src/handler.ts
    at CascadingConfigArrayFactory._finalizeConfigArray (<PATH>\node_modules\@rollup\plugin-eslint\node_modules\@eslint\eslintrc\lib\cascading-config-array-factory.js:521:19)  
    at CascadingConfigArrayFactory.getConfigArrayForFile (<PATH>\node_modules\@rollup\plugin-eslint\node_modules\@eslint\eslintrc\lib\cascading-config-array-factory.js:312:21) 
    at CLIEngine.isPathIgnored (<PATH>\node_modules\@rollup\plugin-eslint\node_modules\eslint\lib\cli-engine\cli-engine.js:1000:18)
    at ESLint.isPathIgnored (<PATH>\node_modules\@rollup\plugin-eslint\node_modules\eslint\lib\eslint\eslint.js:681:26)
    at Object.transform (file:///<PATH>/node_modules/@rollup/plugin-eslint/dist/es/index.js:24:54)
    at <PATH>\node_modules\rollup\dist\shared\rollup.js:989:40

Additional Information

original rollup.config.js (no difference if other plugins are removed):

import commonjs from '@rollup/plugin-commonjs'
import typescript from 'rollup-plugin-typescript2'
import eslint from '@rollup/plugin-eslint'
import resolve from '@rollup/plugin-node-resolve'
import json from '@rollup/plugin-json'

export default {
  input: 'src/handler.ts',
  output: {
    dir: 'dist/cjs',
    format: 'cjs'
  },
  plugins: [
    json(),
    commonjs(),
    resolve(),
    eslint({ throwOnError: true, fix: true }),
    typescript({ useTsconfigDeclarationDir: true })
  ]
}

[ribeiroguilherme]

Is there any workaround for this for the time being?

[manferlo81]

I use the "overrides" entry on package.json, You have to edit it every time you update eslint but it works. The problem is @rollup/plugin-eslint is using eslint@8, the "overrides" entry will force eslint to be whatever version you set there.

{
  "overrides": {
    "eslint": "^9.9.0"
  }
}

Update: It works if you are using eslint@9 but with eslint@8 (with flat config) I am still getting an error.

[Tardo]

@manferlo81 nice!

I have it like this:

"overrides": {
  "@rollup/plugin-eslint": {
    "eslint": "^9.9"
  }
},