Summary

Found this bug when writing code for #46537.

In current eslint setup, you cannot import from dirs whose name start with index like index_patterns in src/plugins dir even if they are in the same folder.

For example:

// src/plugins/data/server/plugin.ts
import { X } from './index_patterns'; // eslint error;
import { Y } from './hello_world'; // OK;

The cause of the problem is that traverseToTopFolder() returns the wrong folder when a folder name starts with 'index'.

You can check it out by running the script below:

const mm = require('micromatch');
const path = require('path');

const from = [
  'src/plugins/**/server/**/*',
  '!src/plugins/**/server/index*',
];

function traverseToTopFolder(src, pattern) {
  while (mm([src], pattern).length > 0) {
    const srcIdx = src.lastIndexOf(path.sep);
    src = src.slice(0, srcIdx);
  }
  return src;
}

console.log(traverseToTopFolder('src/plugins/data/server/plugin.ts', from));
console.log(traverseToTopFolder('src/plugins/data/server/index_patterns/index.ts', from));
console.log(traverseToTopFolder('src/plugins/data/server/dummy/index.ts', from));

Result:

src/plugins/data/server
src/plugins/data/server/index_patterns
src/plugins/data/server

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately
• This includes a feature addition or change that requires a release note and was labeled appropriately