Bug: "Parsing error" for files that have been ignored

[doberkofler]

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• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue.
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Relevant Package

typescript-eslint

Playground Link

No response

Repro Code

It seems as if typescript-eslint would wrongly or not at all skip the files defined in the `ignores` property.
This might be related to #8511 but does not only happen when `extends` is used.

ESLint Config

// @ts-check

import globals from 'globals';
import tseslint from 'typescript-eslint';

export default tseslint.config({
	ignores: [
		'vendor/**/*',
	],
	languageOptions: {
		ecmaVersion: 2021,
		sourceType: 'module',
		globals: {
			...globals.es2021,
		}
	},
	rules: {
		'indent': ['warn', 'tab'],
		'linebreak-style': ['warn', 'unix'],
		'quotes': ['warn', 'single'],
		'semi': ['warn', 'always'],
	},
},
{
	files: ['**/*.js'],
},
{
	files: ['**/*.ts'],
	plugins: {
		'@typescript-eslint': tseslint.plugin,
	},
	languageOptions: {
		parser: tseslint.parser,
		parserOptions: {
			project: true,
		},
	},
	rules: {
		'indent': 'off',
		'@typescript-eslint/indent': ['warn', 'tab'],
		'quotes': 'off',
		'@typescript-eslint/quotes': ['warn', 'single'],
		'semi': 'off',
		'@typescript-eslint/semi': ['warn', 'always'],
	},
});

tsconfig

{
  "compilerOptions": {
    "target": "es2021",
    "module": "commonjs",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true,
    "allowJs": true,
    "checkJs": true
  },
  "include": ["src/**/*.ts"]
}

Expected Result

eslint should ignore the files in the vendor directory

Actual Result

eslint reports parse errors for files in the directory vendor:

0:0  error  Parsing error: ESLint was configured to run on `<tsconfigRootDir>/vendor/file.d.ts` using `parserOptions.project`: tsconfig.json
However, that TSConfig does not include this file. Either:
- Change ESLint's list of included files to not include this file
- Change that TSConfig to include this file
- Create a new TSConfig that includes this file and include it in your parserOptions.project
See the typescript-eslint docs for more info: https://typescript-eslint.io/linting/troubleshooting#i-get-errors-telling-me-eslint-was-configured-to-run--however-that-tsconfig-does-not--none-of-those-tsconfigs-include-this-file

Additional Info

No response

Versions

package	version
@typescript-eslint/eslint-plugin	7.1.0
@typescript-eslint/parser	7.1.0
TypeScript	5.3.3
ESLint	8.57.0
node	20.11.0

[bradzacher]

you can use the --print-config flag to show the config for the file.
I suspect you're butting up against how flat configs work compared to before.

when you specify ignores it specifically only applies to the flat config array item that it is attached to.
Or to illustrate:

export default [
  // this config object will NEVER be applied to `src/ignored.ts`
  { ignores: ['src/ignored.ts'], ...someConfig1 },

  // this config object will ALWAYS be applied to `src/ignored.ts`
  { ...someConfig2 },

  // this config object will NEVER be applied to `src/ignored.ts` -- but only because it doesn't match the pattern
  { files: ['**/*.js'], ...someConfig3 },

  // this config object will ALWAYS be applied to `src/ignored.ts`
  { files: ['**/*.ts'], ...someConfig4 },
];

It's a bit of a confusing switch from "legacy" configs where ignorePatterns applied to the entire config.

In flat configs if you want to specify global ignores you need to pass a config object with JUST the ignores property: https://eslint.org/docs/latest/use/configure/configuration-files-new#globally-ignoring-files-with-ignores

export default [
  // declares that src/ignored.ts is completely ignored by ESLint
  { ignores: ['src/ignored.ts'] },

  // this config object will NEVER be applied to `src/ignored.ts`
  { ...someConfig1 },

  // this config object will NEVER be applied to `src/ignored.ts`
  { ...someConfig2 },

  // this config object will NEVER be applied to `src/ignored.ts`
  { files: ['**/*.js'], ...someConfig3 },

  // this config object will NEVER be applied to `src/ignored.ts`
  { files: ['**/*.ts'], ...someConfig4 },
];

We hint at this new behaviour in our typescript-eslint package docs: https://typescript-eslint.io/packages/typescript-eslint#usage-with-other-plugins

[doberkofler]

Thank you for the thoughtful explanation and sorry i did not spot this myself!

[bradzacher]

It's easy to miss - I messed up a few things and wasted an hour or so the first time I used flat configs. There are some subtle changes to be sure!