[BUG] pnpm symlink compatibility

[ha1fstack]

Describe the bug

┌──────────────────────────────┐
│ OpenNext — Generating bundle │
└──────────────────────────────┘

Bundling middleware function...
Bundling static assets...
Bundling cache assets...
Building server function: default...
node:fs:3086
  binding.copyFile(
          ^

Error: EPERM: operation not permitted, copyfile '...\.next\standalone\node_modules\.pnpm\sharp@0.33.5\node_modules\@img\sharp-wasm32' -> '...\.open-next\server-functions\default\node_modules\.pnpm\sharp@0.33.5\node_modules\@img\sharp-wasm32'
    at copyFileSync (node:fs:3086:11)
    at file:///.../node_modules/.pnpm/@opennextjs+aws@https+++pkg.pr.new+@opennextjs+aws@748/node_modules/@opennextjs/aws/dist/build/copyTracedFiles.js:140:13
    at Map.forEach (<anonymous>)
    at copyTracedFiles (file:///.../node_modules/.pnpm/@opennextjs+aws@https+++pkg.pr.new+@opennextjs+aws@748/node_modules/@opennextjs/aws/dist/build/copyTracedFiles.js:111:17)
    at generateBundle (file:///.../node_modules/.pnpm/@opennextjs+cloudflare@https+++pkg.pr.new+@opennextjs+cloudflare@9a89f04_wrangler@3.109.3_@cl_kqmgsg5g3b7oqvmpys6frm3g2a/node_modules/@opennextjs/cloudflare/dist/cli/build/open-next/createServerBundle.js:106:11)
    at createServerBundle (file:///.../node_modules/.pnpm/@opennextjs+cloudflare@https+++pkg.pr.new+@opennextjs+cloudflare@9a89f04_wrangler@3.109.3_@cl_kqmgsg5g3b7oqvmpys6frm3g2a/node_modules/@opennextjs/cloudflare/dist/cli/build/open-next/createServerBundle.js:66:11)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async build (file:///.../node_modules/.pnpm/@opennextjs+cloudflare@https+++pkg.pr.new+@opennextjs+cloudflare@9a89f04_wrangler@3.109.3_@cl_kqmgsg5g3b7oqvmpys6frm3g2a/node_modules/@opennextjs/cloudflare/dist/cli/build/build.js:74:5)
    at async file:///.../node_modules/.pnpm/@opennextjs+cloudflare@https+++pkg.pr.new+@opennextjs+cloudflare@9a89f04_wrangler@3.109.3_@cl_kqmgsg5g3b7oqvmpys6frm3g2a/node_modules/@opennextjs/cloudflare/dist/cli/index.js:7:1 {
  errno: -4048,
  code: 'EPERM',
  syscall: 'copyfile',
  path: '...\\.next\\standalone\\node_modules\\.pnpm\\sharp@0.33.5\\node_modules\\@img\\sharp-wasm32',
  dest: '...\\.open-next\\server-functions\\default\\node_modules\\.pnpm\\sharp@0.33.5\\node_modules\\@img\\sharp-wasm32'
}

Node.js v22.14.0

Steps to reproduce

• pnpm latest, node lts, windows
• nextjs starter template

pnpm with node-linker=isolated breaks build

1. throws EPERM error while build
2. node_modules folder gets corrupted so have to reinstall dependency from scratch everytime I build

If switched to node-linker=hoisted so symlink is disabled, the problems are gone

tested on windows only, guess other platforms are fine

Expected behavior

• build should work
• node_modules folder should be intact

@opennextjs/cloudflare version

latest stable / canary

Wrangler version

3.109.3

next info output

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Education
  Available memory (MB): 65278
  Available CPU cores: 24
Binaries:
  Node: 22.14.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.5.0
Relevant Packages:
  next: 15.1.7 // Latest available version is detected (15.1.7).
  eslint-config-next: 15.1.7
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.3
Next.js Config:
  output: N/A

Additional context

No response

[vicb]

We will not support windows without WSL (see #577 for rationale).

[joshua92y]

For anyone still hitting this: we tracked down the root cause in @opennextjs/aws copyTracedFiles — on Windows, pnpm directory symlinks are recreated from the raw readlink value without a link type, and Node falls back to a file-type symlink when the target does not exist yet, producing links Windows cannot traverse (esbuild then fails with "Cannot read directory ...: Access is denied").

Filed upstream with full analysis and a verified fix (junctions resolved against the destination directory — no node-linker=hoisted switch needed, works with the default isolated layout):

• Issue: copyTracedFiles recreates pnpm symlinks as broken links on Windows (esbuild "Cannot read directory: Access is denied") opennextjs-aws#1184
• PR: fix: recreate pnpm symlinks as junctions on Windows in copyTracedFiles opennextjs-aws#1185