Bug: Build fails on new projects due to incompatibility with eslint@9.29.0

[dkvc]

Error

This issue affects all new Vue projects created with the standard scaffolding (pnpm create vue@latest) since the release of eslint@9.29.0. It can also be reproduced on existing projects by updating eslint from 9.28.0 to 9.29.0

The default eslint.config.ts generated by create-vue now fails during the vue-tsc --build step with a TS2345 type error.

Possible Cause

The API contract of defineConfigWithVueTs appears to be broken by the eslint@9.29.0 release. The function expects a very specific object shape, but helper functions from the eslint package itself now return objects that no longer match that shape.

Here's the commit that contains the changes to FlatConfig in eslint: eslint/eslint@7ab77a2

Reproducing the Bug

1. Run pnpm create vue@latest
2. Select Typescript and ESLint Support.
3. Run pnpm i. The latest version eslint@9.29.0 will be installed.
4. Run pnpm build.

Error Log

eslint.config.ts:18:3 - error TS2345: Argument of type 'Config<RulesRecord>' is not assignable to parameter of type 'InfiniteDepthConfigWithExtendsAndVueSupport'.
  Type 'Config<RulesRecord>' is not assignable to type 'ConfigItemWithExtendsAndVueSupport'.
    Types of property 'languageOptions' are incompatible.
      Type 'import("/mnt/e/Repos/test/test/node_modules/.pnpm/eslint@9.29.0_jiti@2.4.2/node_modules/eslint/lib/types/index").Linter.LanguageOptions | undefined' is not assignable to type 'import("/mnt/e/Repos/test/test/node_modules/.pnpm/@typescript-eslint+utils@8.34.0_eslint@9.29.0_jiti@2.4.2__typescript@5.8.3/node_modules/@typescript-eslint/utils/dist/ts-eslint/Config").FlatConfig.LanguageOptions | undefined'.
        Type 'import("/mnt/e/Repos/test/test/node_modules/.pnpm/eslint@9.29.0_jiti@2.4.2/node_modules/eslint/lib/types/index").Linter.LanguageOptions' is not assignable to type 'import("/mnt/e/Repos/test/test/node_modules/.pnpm/@typescript-eslint+utils@8.34.0_eslint@9.29.0_jiti@2.4.2__typescript@5.8.3/node_modules/@typescript-eslint/utils/dist/ts-eslint/Config").FlatConfig.LanguageOptions'.
          Types of property 'ecmaVersion' are incompatible.
            Type 'EcmaVersion | undefined' is not assignable to type 'EcmaVersion'.
              Type '17' is not assignable to type 'EcmaVersion'.

18   globalIgnores(['**/dist/**', '**/dist-ssr/**', '**/coverage/**']),
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Notes/Assumptions

I assume this is a type incompatibility between eslint and @typescript-eslint/utils.

eslint-config-typescript/src/utilities.ts

Lines 17 to 24 in 0a6480d

	type ConfigItem = TSESLint.FlatConfig.Config
	type InfiniteDepthConfigWithExtendsAndVueSupport =
	| TsEslintConfigForVue
	| ConfigItemWithExtendsAndVueSupport
	| InfiniteDepthConfigWithExtendsAndVueSupport[]
	interface ConfigItemWithExtendsAndVueSupport extends ConfigItem {
	extends?: InfiniteDepthConfigWithExtendsAndVueSupport[]
	}

Here, ConfigItemWithExtendsAndVueSupport depends on ConfigItem, which further depends on TSESLint.FlatConfig.Config. Based on the error log, it appears LanguageOptions from @typescript-eslint/utils requires changes.

https://github.com/typescript-eslint/typescript-eslint/blob/de8943e98e188d83801ec1044ffc69451db1aa63/packages/utils/src/ts-eslint/Config.ts#L215-L252

[qiukeren]

it suddenly occurs today even not yesterday

from here, vue created projects have this problem, not only 9.28.0

    "eslint": "^9.22.0",

SHELL: npm run build
 
> index1@0.0.0 build
> run-p type-check "build-only {@}" --


> index1@0.0.0 build-only
> vite build


> index1@0.0.0 type-check
> vue-tsc --build

vite v6.3.5 building for production...
transforming (1) src/main.tseslint.config.ts:17:3 - error TS2345: Argument of type 'Config<RulesRecord>' is not assignable to parameter of type 'InfiniteDepthConfigWithExtendsAndVueSupport'.
  Type 'Config<RulesRecord>' is not assignable to type 'ConfigItemWithExtendsAndVueSupport'.
    Types of property 'languageOptions' are incompatible.
      Type 'import("/DIR/src/demo/src/main/index1/node_modules/eslint/lib/types/index").Linter.LanguageOptions | undefined' is not assignable to type 'import("/DIR/src/demo/src/main/index1/node_modules/@typescript-eslint/utils/dist/ts-eslint/Config").FlatConfig.LanguageOptions | undefined'.
        Type 'import("/DIR/src/demo/src/main/index1/node_modules/eslint/lib/types/index").Linter.LanguageOptions' is not assignable to type 'import("/DIR/src/demo/src/main/index1/node_modules/@typescript-eslint/utils/dist/ts-eslint/Config").FlatConfig.LanguageOptions'.
          Types of property 'ecmaVersion' are incompatible.
            Type 'EcmaVersion | undefined' is not assignable to type 'EcmaVersion'.
              Type '17' is not assignable to type 'EcmaVersion'.

17   globalIgnores(['**/dist/**', '**/dist-ssr/**', '**/coverage/**']),
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

✓ 53 modules transformed.
dist/index.html                      0.43 kB │ gzip:  0.29 kB
dist/assets/AboutView-CSIvawM9.css   0.09 kB │ gzip:  0.10 kB
dist/assets/index-5dJgFXHu.css       4.21 kB │ gzip:  1.30 kB
dist/assets/AboutView-B6UJm9Jx.js    0.23 kB │ gzip:  0.21 kB
dist/assets/index-Pj5_I0LE.js       96.49 kB │ gzip: 37.94 kB
✓ built in 851ms

Found 1 error.

ERROR: "type-check" exited with 2.
SHELL:  cat package.json 
{
  "name": "index1",
  "version": "0.0.0",
  "private": true,
  "type": "module",
  "scripts": {
    "dev": "vite",
    "build": "run-p type-check \"build-only {@}\" --",
    "preview": "vite preview",
    "build-only": "vite build",
    "type-check": "vue-tsc --build",
    "lint": "eslint . --fix",
    "format": "prettier --write src/"
  },
  "dependencies": {
    "pinia": "^3.0.1",
    "vue": "^3.5.13",
    "vue-router": "^4.5.0"
  },
  "devDependencies": {
    "@tsconfig/node22": "^22.0.1",
    "@types/node": "^22.14.0",
    "@vitejs/plugin-vue": "^5.2.3",
    "@vue/eslint-config-prettier": "^10.2.0",
    "@vue/eslint-config-typescript": "^14.5.0",
    "@vue/tsconfig": "^0.7.0",
    "eslint": "^9.22.0",
    "eslint-plugin-vue": "~10.0.0",
    "jiti": "^2.4.2",
    "npm-run-all2": "^7.0.2",
    "prettier": "3.5.3",
    "typescript": "~5.8.0",
    "vite": "^6.2.4",
    "vite-plugin-vue-devtools": "^7.7.2",
    "vue-tsc": "^2.2.8"
  }
}

[haoqunjiang]

The fix is pending release: typescript-eslint/typescript-eslint#11304

[haoqunjiang]

We release a latest version every Monday at 17:00 UTC (Tuesdays at 12:30 AM GMT+7:30) using the latest commit to main at that time. This release is performed automatically by a Github action located in a private repository. This release goes to the standard latest tag on npm.

It will be released soon.

[haoqunjiang]

Fixed in @typescript-eslint/types 8.34.1