Support Yarn 2 link protocol aliases

Clear and concise description of the problem

Yarn 2 offers the link protocol as a tool-agnostic way to configure aliases: https://yarnpkg.com/features/protocols/#why-is-the-link-protocol-recommended-over-aliases-for-path-mapping

{
  "dependencies": {
    "src": "link:./src"
  }
}

The problem is that Vite tries to pre-bundle the linked directory as a dependency

error when starting dev server:
Error: The following dependencies are imported but could not be resolved:

  src/<path> (imported by <path>)

Suggested solution

Vite could recognize this pattern by either:

• detecting that the linked folder is within the project root;
• not attempting to pre-bundle “link:” dependencies altogether as they are not treated as packages by yarn.

Alternative

As a work-around this works:

export default defineConfig({
  optimizeDeps: {
    exclude: ["src"],
  },
});

UPDATE: it doesn’t work. But resolve.alias can be used instead.

But it’d be nicer to have this handled automatically.

Additional context

[drazik]

Is anything planned to fix this? It would be awesome if Vite worked with this Yarn feature. It makes alias tool-agnostic. Currently I have it enabled and working for multiple tools, but it fails in Vite, so I have to manually duplicate aliases in vite.config.ts.

I would be happy to help if possible, but I am a newcomer so I will need help entering Vite’s codebase I think.

[merceyz]

From https://github.com/vitejs/vite/issues/2825#issuecomment-812932848 @swandir

NPM does not support “link:”;

While that is true it does support file: which achieves the same thing.

PNPM crashes the install if a “link:”-ed directory does not contain package.json;

This was fixed in pnpm v7.