SSR not working with Bun since canary 9

[Jayllyz]

Before canary 9 this works good.
Bun is v1.2.19

bun --bun run build
$ turbo run build
turbo 2.5.5

next build --turbopack
   ▲ Next.js 15.4.2-canary.15 (Turbopack)
   - Environments: .env
   - Experiments (use with caution):
     ⨯ reactCompiler
     · serverActions
     · optimizePackageImports
     ✓ browserDebugInfoInTerminal
     ✓ turbopackPersistentCaching

   Creating an optimized production build ...
 ✓ Finished writing to disk in 376ms
 ✓ Compiled successfully in 1589ms
   Linting and checking validity of types  ... ✓ Finished writing to persistent cache in 525ms
 ✓ Linting and checking validity of types
 ✓ Collecting page data
Error occurred prerendering page "/register". Read more: https://nextjs.org/docs/messages/prerender-error
Error: Failed to load chunk server/chunks/ssr/d0131_@hookform_resolvers_zod_dist_zod_mjs_e05dfee4._.js from parent module 8561
    at loadChunkAsync (.next/server/chunks/ssr/[turbopack]_runtime.js:582:36)
    at processTicksAndRejections (null) {
  digest: '259102768',
  [cause]: TypeError: Expected CommonJS module to have a function wrapper. If you weren't messing around with Bun's internals, this is a bug
in Bun
      at anonymous (null)
      at loadChunkUncached (.next/server/chunks/ssr/[turbopack]_runtime.js:548:26)
      at loadChunkAsync (.next/server/chunks/ssr/[turbopack]_runtime.js:574:13)
}
Export encountered an error on /register/page: /register, exiting the build.
 ⨯ Next.js build worker exited with code: 1 and signal: null

[sedegah]

You're getting this error because Turbopack (in Next.js canary.15) is generating a server chunk that Bun (v1.2.19) can't properly load. The issue is likely caused by a module like @hookform/resolvers/zod being compiled into a format Bun doesn't support well especially when mixing CommonJS and ESM.

You said it worked fine before canary 9. That means a change in Turbopack after that version broke compatibility with Bun.

Fixes

1. Downgrade Next.js
   Go back to the last working version:

2. Disable Turbopack
   Use the stable Webpack bundler instead:

3. Isolate the problematic module
   Try dynamically importing @hookform/resolvers/zod:

Stick to canary.9 or use --no-turbo for now if you're using Bun.

[hrougier]

I encountered the exact same issue, and downgrading to 15.4.2-canary.8 resolved it.
It seems the problem might have been introduced by #81738, which was merged in canary.9.

Do you think we should open a new issue for this?

Edit:

Just to add, starting from canary.9, the issue doesn't occur on Vercel builds which also use Bun 1.2.19 but only as a package manager, guess it runs the build script through node.