Code elimination broken for module that exports frontend and Node.js

Bug report

Describe the bug

The code elimination is broken, if you import from a file, which exports both frontend and Node.js code.

To Reproduce

Clone and run: https://github.com/timsuchanek/build-cv-messing-around

Expected behavior

The code elimination should sort out the frontend and Node.js code correctly.

Screenshots

System information

• OS: Ubuntu 20
• Version of Next.js: 9.5.2
• Version of Node.js: 14.8.0

Additional context

This is an isolated reproduction of a problem a Prisma user hit with running Prisma Client in getStaticProps https://github.com/prisma/prisma/issues/3252

[fimbault]

I’ve tested that under a slightly different setup, using SQLite as a sort of extreme case (to avoid backend calls for data that is potentially configurable, like in a CMS - updates are done through git push -, but runtime access in readonly mode and without having to maintain it on a central server). In some settings it works, in others it doesn’t.

Here’s an example of stack trace when it doesn’t work:

error - ./node_modules/@prisma/client/runtime/index.js:87:2855 Module not found: Can’t resolve ‘async_hooks’ null Could not find files for / in .next/build-manifest.json

so it fails on the instruction {AsyncResource:Iy}=required(“async_hook”)

Note : I retried this morning, and the example works. So I’m not sure what happened. If I can reproduce, I’ll publish a code example.

[timneutkens]

As of right now it’s not possible to have both client-side JS and Node.js-specific code as the tree shaking of getStaticProps / getStaticPaths works on the module level, it’s not a whole program optimization. You can see what is removed and what is not here: https://next-code-elimination.now.sh/

The elimination is only applied to page files in the pages directory.