[divybot]

Fixes deno desktop on Windows, where the webview and raw backends were broken (cef worked). The root cause was in the laufey native backend runtime (littledivy/laufey); this PR consumes the fixed laufey v0.4.1 and adds a Windows dev-workflow fix.

The two laufey bugs (fixed upstream in laufey v0.4.1)

1. raw (winit) — the backend still declared LAUFEY_API_VERSION = 25 and its laufey_backend_api struct was missing the five custom-scheme vtable pointers added to the C ABI in v26. The deno-side capi (v26) rejects any backend whose version != 26, so it failed to load:

   API version mismatch: expected 26, got 25
   Runtime init failed with code: -2
   

   Fixed by adding the five trailing fields (null) so the struct matches the v26 layout, and bumping the constant to 26.

2. webview — Failed to create WebView2 environment (CO_E_NOTINITIALIZED, blank window), or an immediate 0xc0000409 crash for some users. WebView2 is single-threaded-apartment; the message loop runs on WinMain's thread, but create_window ran WebView2 creation directly on the runtime's worker thread (no COM init, no message pump) → environment creation fails and the controller callback never fires. Fixed by marshaling all WebView2/COM work to the UI thread (message-only dispatcher window + RunOnUiThread). Also hardens the app:// path that was suspected upstream (retry env creation without the custom scheme; try/catch around the resource handler).

deno-side changes here

• Bump laufey 0.4.0 → 0.4.1 and regenerate cli/laufey_sums.lock from the v0.4.1 SHA256SUMS (digests verified against the published archives out-of-band).
• locate_dev_backend_binary only ever looked for extensionless binaries, so LAUFEY_DEV_DIR could never resolve a backend on Windows (laufey_winit.exe etc.). Append the host EXE_SUFFIX.

Verification (Windows 11, x86_64)

Reproduced both failures and verified the fix end-to-end through deno's real download/launch path with the published v0.4.1 backend archives. All three backends now open a working native window — before/after screenshots in the comment below.

Refs #35562

Closes denoland/divybot#610

[divybot]

Windows 11 verification — all three backends

Reproduced and fixed on a real Windows 11 box (x86_64), deno desktop --backend <b> --hmr app.ts serving a tiny HTML page.

raw (winit)

Before: no window —

API version mismatch: expected 26, got 25
Runtime init failed with code: -2

After: native window opens (blank content is expected — raw has no webview; apps render via the raw window handle).

webview (WebView2)

Before: no window —

Failed to create WebView2 environment

(CO_E_NOTINITIALIZED / 0x800401f0; some users saw an immediate 0xc0000409 crash instead.)
After: window renders the served page.

cef (control — already worked, unchanged)

Backends were built from littledivy/laufey fix/windows-webview-raw-backends (released as v0.4.1) and run through the exact deno desktop download/launch path (cached backend exe swapped in place).

[divybot]

Upstream: the backend fixes are in littledivy/laufey main and shipped in v0.4.1 (commits fix(winit): bump backend to API v26 … and fix(webview): drive WebView2 from the UI thread on Windows). laufey's own CI is green for those commits (lint / Windows winit+webview builds / capi tests).

The screenshots above were captured running the published v0.4.1 laufey-{webview,winit}-x86_64-pc-windows-msvc archives through deno desktop's real download/launch path on Windows 11 — cef unchanged (control), webview now renders the served page, raw now opens a native window (blank is expected — raw has no webview).