Including eslint-plugin-import cause lint postpone

[ogonkov]

When including eslint-plugin-import (even without any rules) cause tests to "stuck" after showing lint results.

Lint shows results, and then waits for some time before shell receives exit code.

Installed eslint dependencies:

├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]

Reduced eslint config

{
    plugins: [
        'react',
        'react-hooks',
        'jsx-a11y',
        // 'import'
    ],
    parser: '@babel/eslint-parser',
    parserOptions: {
        ecmaVersion: 10,
        sourceType: 'module',
        impliedStrict: true,
        ecmaFeatures: {
            jsx: true
        }
    },
    env: {
        browser: true,
        amd: true,
        es6: true
    },
    'extends': [
        'eslint:recommended',
        'plugin:react/recommended',
        'plugin:jsx-a11y/recommended'
    ],
    settings: {
        'import/resolver': {
            webpack: {
                config: path.resolve(__dirname, 'app/webpack.config.js')
            }
        },
    }
}

When un-commenting import line, i see this strange behaviour, like something happens in background after lint finished.

✖ 23 problems (6 errors, 17 warnings)
  3 errors and 4 warnings potentially fixable with the `--fix` option.

// <-- Stuck happens here, before showing log bellow

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] lint:js-staged: `CI_MERGE_REQUEST_TARGET_BRANCH_NAME=master ./contrib/ci/gitlab-lint-changed-js.sh`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the [email protected] lint:js-staged script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

[ljharb]

That’s very strange; with no rules enabled, i wouldn’t expect the plugin to do anything. If you remove all the other things from your config, do you still see this behavior?

[ogonkov]

You mean other plugins? When config is run without import plugin everything happen smooth. That make me guess that problem is in import plugin

[ogonkov]

Seems like without settings.import/resolver problem is gone.

[ljharb]

What’s in your webpack config? Perhaps the contents of that are contributing?

[ogonkov]

Oh. Wow. Thank you, @ljharb!

My webpack config returns promise, and looks like it was the reason of that stuck.

Even more, this seems was a reason of memory leak, that was the initial reason of debugging eslint config. Looks like that eslint-plugin-import/eslint-import-resolver-webpack is not working well with webpack configs, that returns promise.

Should i file another bug?

[ljharb]

Since eslint runs synchronously, I don't think it's possible for an async webpack config to integrate with eslint.

[ljharb]

Closing in favor of #883.

[ogonkov]

That should be added to readme, to avoid further mistakes.

[ljharb]

Sure, a PR to do so would be appreciated.