Problem

When using experimentalDts in a with components in a subfolder the generated output points to files that don't exist.

Version info

tsup 8.0.1
@microsoft/api-extractor 7.38.3

Example

// input files
./src
  components/
    ComponentA/
      index.tsx

// tsup config
export default defineConfig({
      target: 'esnext',
      platform: 'neutral',
      format: 'esm',
      experimentalDts: true,
      entry: [ "./src/components/ComponentA.tsx" ]
});

// output files (Note how the components/ folder does not exist in dist)
./dist
  ComponentA/
      index.tsx
  _tsup-dts-rollup.d.ts

Now when looking into the dist/_tsup-dts-rollup.d.ts file it contains references to ./components/ComponentA resulting in broken typings.

Proposed fix

The generated paths in dist/_tsup-dts-rollup.d.ts somehow reference nonexisting files when the entry code is in a subdirectory, so the fix would probably have to check the actual location of the output file and reference that instead.

Other feedback

@ocavue
I originally tried out the experimentalDts option because I am building a number of entries (20+) and the dts build is very slow (~30 seconds). With the new experimentalDts option this time went down to ~7 seconds. Thanks for that great speed improvement. So it would be very nice to use if the generated paths were correct.