Reproduction link or steps

1. Create a tsdown config:

  import { defineConfig } from 'tsdown'

  export default defineConfig({
    entry: ['./src/index.ts'],
    format: ['esm'],
    unbundle: true,
    dts: true,
    exports: {
      devExports: true,
    },
  })

2. Create this file structure:

  src/
    index.ts
    components/
      text/
        index.ts

3. Run tsdown. It outputs: dist/

    index.js
    components/
      text/
        index.js

4. Check package.json. Only main export is generated:

  {
    "exports": {
      ".": "./src/index.ts",
      "./package.json": "./package.json"
    }
  }

What is expected?

devExports: true should generate subpath exports for each unbundled module:

  {
    "exports": {
      ".": "./src/index.ts",
      "./text": "./src/components/text/index.ts"
    },
    "publishConfig": {
      "exports": {
        ".": "./dist/index.js",
        "./text": "./dist/components/text/index.js"
      }
    }
  }

What is actually happening?

Only the main . export is generated. Consumers can't import individual unbundled modules:

  // Doesn't work - no subpath export defined
  import { Text } from '@my-lib/text'

  // Only this works - defeats the purpose of unbundling
  import { Text } from '@my-lib'

Any additional comments?

This makes it hard to build component libraries following modern patterns (Base UI, Radix UI, etc.) where each component is individually importable for better tree-shaking.

Current workaround is setting exports: false and manually maintaining all subpath exports, but that defeats the purpose of devExports: true.

When unbundle: true, it would be useful if devExports scanned the output structure and auto-generated subpath exports.