[Bug]: Unable to bundle types from dependency while importing from root but works for sub-path modules

[Asuka109]

Version

System:
    OS: macOS 15.0
    CPU: (10) arm64 Apple M1 Pro
    Memory: 151.06 MB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Browsers:
    Safari: 18.0
  npmPackages:
    @rslib/core: ^0.0.16 => 0.0.16

Details

There is a minimal repro slimmed from a package using Rsbuild.

src/index.ts

import type { RsbuildPluginAPI as Foo } from 'my-kit';
import type { RsbuildPluginAPI as Bar } from 'my-kit/plugin';

export type { Foo, Bar };

While all the things is actually exported from ./node_modules/my-kit/dist-types/types/plugin.d.ts.

node_modules/my-kit/dist-types
├── index.d.ts
└── types
    ├── index.d.ts
    └── plugin.d.ts

The weird thing is if I import types from my-kit (./node_modules/my-kit/dist-types/index.d.ts). It will come into being a relative path import statement from ./types (but there no dist/types/index.d.ts or somethings like it in there).

dist/index.d.ts (actual)

import { RsbuildPluginAPI as Foo } from './types';

export declare type Bar = {};

export { Foo }

export { }

But I expected it should be bundle into the dist/index.d.ts just like if I import the some type from the sub-path module my-kit/plugin (./node_modules/my-kit/dist-types/types/plugin.d.ts). It would be seems like:

dist/index.d.ts (expected)

export declare type Foo = {};

export declare type Bar = {};

export { Foo, Foo }

Reproduce link

https://github.com/Asuka109/repro-rslib-relative-path-typings

Reproduce Steps

1. pnpm install
2. pnpm build

[Timeless0911]

same as #470

If I write full index path like below, it work as expected.

- export type { RsbuildPluginAPI } from './types';

+ export type { RsbuildPluginAPI } from './types/index';

[Asuka109]

It sounds like a ES Module limitation or something which won't resolve any directory as a module by appending ./index...

[fi3ework]

type-fest is shipped in CJS mode, so api-extractor should follow Node.js resolution strategy, which should handles /index.