Bug: ESLint API cannot find eslint-recommended.js

[daidodo]

Environment

Node version: v16.10.0
npm version: 7.24.0
Local ESLint version: 8.8.0
Global ESLint version: N/A
Operating System: macOS Big Sur

What parser are you using?

Default (Espree)

What did you do?

To reproduce the issue:

• git clone https://github.com/daidodo/eslint-api-issue.git
• cd eslint-api-issue && npm i && npx webpack
• node dist/main.js src/index.ts

What did you expect to happen?

I expect the output is the ESLint resolved config for the given file.
If you run npx tsc && node dist/main.js src/index.ts, you can get:

ESLint version: 8.8.0
eslint object: ESLint {}
Resolving ESLint config:
{
  env: {},
  globals: {},
  noInlineConfig: undefined,
  parser: null,
  parserOptions: {},
  plugins: [],
  reportUnusedDisableDirectives: undefined,
  rules: {
    'no-unused-vars': [ 'warn', [Object] ],
    'constructor-super': [ 'error' ],
    'for-direction': [ 'error' ],
    'getter-return': [ 'error' ],
    'no-async-promise-executor': [ 'error' ],
    'no-case-declarations': [ 'error' ],
    'no-class-assign': [ 'error' ],
    'no-compare-neg-zero': [ 'error' ],
    'no-cond-assign': [ 'error' ],
    'no-const-assign': [ 'error' ],
    'no-constant-condition': [ 'error' ],
    'no-control-regex': [ 'error' ],
    'no-debugger': [ 'error' ],
    'no-delete-var': [ 'error' ],
    'no-dupe-args': [ 'error' ],
    'no-dupe-class-members': [ 'error' ],
    'no-dupe-else-if': [ 'error' ],
    'no-dupe-keys': [ 'error' ],
    'no-duplicate-case': [ 'error' ],
    'no-empty': [ 'error' ],
    'no-empty-character-class': [ 'error' ],
    'no-empty-pattern': [ 'error' ],
    'no-ex-assign': [ 'error' ],
    'no-extra-boolean-cast': [ 'error' ],
    'no-extra-semi': [ 'error' ],
    'no-fallthrough': [ 'error' ],
    'no-func-assign': [ 'error' ],
    'no-global-assign': [ 'error' ],
    'no-import-assign': [ 'error' ],
    'no-inner-declarations': [ 'error' ],
    'no-invalid-regexp': [ 'error' ],
    'no-irregular-whitespace': [ 'error' ],
    'no-loss-of-precision': [ 'error' ],
    'no-misleading-character-class': [ 'error' ],
    'no-mixed-spaces-and-tabs': [ 'error' ],
    'no-new-symbol': [ 'error' ],
    'no-nonoctal-decimal-escape': [ 'error' ],
    'no-obj-calls': [ 'error' ],
    'no-octal': [ 'error' ],
    'no-prototype-builtins': [ 'error' ],
    'no-redeclare': [ 'error' ],
    'no-regex-spaces': [ 'error' ],
    'no-self-assign': [ 'error' ],
    'no-setter-return': [ 'error' ],
    'no-shadow-restricted-names': [ 'error' ],
    'no-sparse-arrays': [ 'error' ],
    'no-this-before-super': [ 'error' ],
    'no-undef': [ 'error' ],
    'no-unexpected-multiline': [ 'error' ],
    'no-unreachable': [ 'error' ],
    'no-unsafe-finally': [ 'error' ],
    'no-unsafe-negation': [ 'error' ],
    'no-unsafe-optional-chaining': [ 'error' ],
    'no-unused-labels': [ 'error' ],
    'no-useless-backreference': [ 'error' ],
    'no-useless-catch': [ 'error' ],
    'no-useless-escape': [ 'error' ],
    'no-with': [ 'error' ],
    'require-yield': [ 'error' ],
    'use-isnan': [ 'error' ],
    'valid-typeof': [ 'error' ]
  },
  settings: {},
  ignorePatterns: [ '**/xxx.js' ]
}

What actually happened?

If webpacked, the output would be:

ESLint version: 8.8.0
eslint object: ESLint {}

Error: Cannot read config file: /Users/xxx/Desktop/private/projects/conf/eslint-recommended.js
Error: Cannot find module '/Users/xxx/Desktop/private/projects/conf/eslint-recommended.js'
Require stack:
- /Users/xxx/Desktop/private/projects/eslint-api-issue/dist/noop.js
Referenced from: /Users/xxx/Desktop/private/projects/eslint-api-issue/package.json

Participation

• I am willing to submit a pull request for this issue.

Additional comments

I've submitted a similar issue (#13974) but got aged.
My guess is the __dirname in lib/cli-engine/cli-engine.js causes the issue. But I don't have enough context to confirm or fix it.

Thanks!

[nzakas]

As we discussed in the original issue, ESLint isn’t designed to be bundled with Webpack, so this isn’t something the team can prioritize. If you want to experiment with fixing the problem and submit a pull request, we can review it.

[daidodo]

@nzakas, thanks for the response!

Could you share your thoughts about how it should be fixed?
I'm new to internal of ESLint so any guidance would help.

[daidodo]

I've dived a bit and found this function which loads config extends.
I think one solution is to cache the internal extend objects (eslint:recommended and eslint:all) instead of their file paths. Both ways the CLI (e.g. eslint) will get the same result.
What do you think? Thanks!

[nzakas]

The problem is that all config data is loaded via filepaths, so we can’t just swap in an object without changing a lot of the complex plumbing of the config cascade.

[daidodo]

Correct me if I'm wrong.

There are two parts of the changes:

1. Setting extend objects to the cache. That can be done by changing all the places that extend file paths are set. At a glance, those places are:

   • eslint/lib/cli-engine/cli-engine.js

     Lines 619 to 620 in 5d60812

     	eslintRecommendedPath: path.resolve(__dirname, "../../conf/eslint-recommended.js"),
     	eslintAllPath: path.resolve(__dirname, "../../conf/eslint-all.js")

     
     Change to:

     eslintRecommendedConfig: require("../../conf/eslint-recommended.js"), 
     eslintAllConfig: require("../../conf/eslint-all.js")

   • eslint/lib/cli-engine/file-enumerator.js

     Lines 218 to 219 in 9a4ae3b

     	eslintRecommendedPath: path.resolve(__dirname, "../../conf/eslint-recommended.js"),
     	eslintAllPath: path.resolve(__dirname, "../../conf/eslint-all.js")

   • eslintrc: flat-compat.js
   • eslintrc: cascading-config-array-factory.js
   • eslintrc: config-array-factory.js
2. Changing the way extend config is calculated. That's to update _loadExtendedBuiltInConfig as follow:

    // ...
        if (extendName === "eslint:recommended") {
            return this._normalizeConfigData(this.eslintRecommendedConfig, {
                ...ctx,
                name: `${ctx.name} » ${extendName}`
            });
        }
    // ...

Plus there are changes to class ConfigArrayFactory constructor, of course.

Do you think if it would work? Thanks!

[nzakas]

I don’t know. Why don’t you try it and see what happens?

[mdjermanovic]

Reopening as this isn't fixed until #15616 gets merged.