cexbrayat/tseslint-config-repro

TypeScript ESLint projectService

The project has 2 tsconfig files:

• tsconfig.app.json, to compile src/app.ts and adds types from other.d.ts, with a test function typed as any (unused in the compiled code).
• tsconfig.test.json, to compile src/test.ts and adds types from test.d.ts, with a test function properly typed (used in the compiled code).

Both compilation work fine: pnpm tsc-app and pnpm tsc-test.

The following ESLint config is used:

// @ts-check

import eslint from '@eslint/js';
import tseslint from 'typescript-eslint';

export default tseslint.config(
  {
    files: ['src/*.ts'],
    extends: [
      eslint.configs.recommended,
      ...tseslint.configs.recommendedTypeChecked,    
    ],
    languageOptions: {
      parserOptions: {
        // this doesn't work, as tseslint uses the wrong tsconfig for the test.ts file
        projectService: true,
        // this works, but is not ideal
        // project: ['./tsconfig.app.json', './tsconfig.test.json'],
        tsconfigRootDir: import.meta.dirname
      },
    }
  }
);

When using projectService: true, the lint command fails with:

❯ pnpm lint

> tseslint-config-repro@1.0.0 lint /Users/cedric/Code/temp/tseslint-config-repro
> eslint .


/Users/cedric/Code/temp/tseslint-config-repro/src/test.ts
  1:1  error  Unsafe call of an `any` typed value  @typescript-eslint/no-unsafe-call

✖ 1 problem (1 error, 0 warnings)

It does work when using project: ['./tsconfig.app.json', './tsconfig.test.json'].

I suppose that projectService does not use the proper tsconfig. This is a minimal reproduction of what we saw on Angular projects (which are generated with 2 tsconfig files as well).