fix(desktop): avoid recursive cpSync in stage-native-deps (Windows build crash)

[danilofalcao]

What does this PR do?

Fixes a hard crash that makes the desktop app impossible to build/package on Windows.

npm run pack (invoked by hermes desktop) dies silently at the stage-native-deps step with exit code 3221226505 (0xC0000409 / STATUS_STACK_BUFFER_OVERRUN):

bundled ...\dist\electron-preload.js
npm error Lifecycle script `build` failed with error:
npm error code 3221226505

Root cause: Node 22.x's native recursive cpSync (cpSyncCopyDir) is unreliable on Windows. cpSync(src, dest, { recursive: true }) throws EIO: "Access is denied." on the \\?\-prefixed destination — reproducible even for a plain directory of .js files — and hard-crashes the whole process (0xC0000409) when copying node-pty's conpty payload (OpenConsole.exe + conpty.dll). Per-file, non-recursive cpSync works every time.

Because the fault is native (not a JS exception), there's no stack trace and it can't be caught/retried — the process just vanishes. The desktop launcher then misreports this as a blocked Electron download and retries via a mirror, but the build never actually reaches the electron-builder step, so the retry can't help.

The fix routes the two recursive-cpSync directory copies in stage-native-deps.mjs through a small manual walk (copyDirRecursive) that copies files individually — the exact pattern the neighbouring copyGlobByExt already uses reliably. No behavior change on macOS/Linux (they were fine; this just uses a codepath that also works on Windows).

Related Issue

No linked issue — happy to open one if you'd prefer to track it. Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• apps/desktop/scripts/stage-native-deps.mjs
  • Added copyDirRecursive(srcDir, destDir) — walks a directory with readdirSync and copies each file with a non-recursive cpSync (recursing into subdirs itself), with a comment explaining why recursive cpSync is avoided.
  • Replaced the two cpSync(dir, { recursive: true }) calls (copyBuildRelease for build/Release/* subdirs, and the prebuilds/<target>/conpty copy) with copyDirRecursive.
• apps/desktop/scripts/stage-native-deps.test.mjs (new)
  • Verifies copyDirRecursive reproduces a nested tree (incl. a conpty/ subdir with binary blobs) with byte-exact copies.
  • Verifies it creates the destination even for an empty source.
  • Regression guard asserting stage-native-deps.mjs never calls cpSync with { recursive: true } (the crashing API).

How to Test

Reproduction (Windows 11, Node 22.x, from apps/desktop):

1. On main: npm run build → crashes at stage-native-deps with npm error code 3221226505, no stack trace.
2. With this PR: npm run build → exits 0; npm run pack → exits 0 and produces release/win-unpacked/Hermes.exe with the node-pty conpty binaries staged under resources/app.asar.unpacked/dist/node_modules/node-pty/.

Unit tests:

cd apps/desktop && node --test scripts/stage-native-deps.test.mjs
# tests 3  pass 3  fail 0

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass — N/A, this is a desktop build-script (Node) change; ran node --test scripts/stage-native-deps.test.mjs (3/3 pass) instead
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Windows 11 (WSL2), Node 22.23.x — full npm run pack now succeeds

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — code comment added explaining the Windows cpSync pitfall; no user-facing docs affected
• I've updated cli-config.yaml.example if I added/changed config keys — N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — N/A
• I've considered cross-platform impact (Windows, macOS) — macOS/Linux behavior unchanged (they already worked); fix only swaps to a codepath that additionally works on Windows
• I've updated tool descriptions/schemas if I changed tool behavior — N/A

Screenshots / Logs

Before (on main):

  dist\electron-preload.js  15.5kb
bundled ...\dist\electron-preload.js
npm error Lifecycle script `build` failed with error:
npm error code 3221226505

After (this PR):

[stage-native-deps] staged node-pty (win32-x64) -> ...\apps\desktop\dist\node_modules\node-pty
> hermes@0.17.0 postbuild
✓ assert-dist-built: dist/index.html + assets present
  • packaging       platform=win32 arch=x64 electron=40.10.2 appOutDir=release\win-unpacked
===PACK_ERRORLEVEL=0===