Desktop: renderer unresponsive on startup — marked.js walkTokens synchronous Markdown AST traversal blocks UI thread

[ACbye]

Description

OpenCode Desktop v1.17.7 on Windows 10 x64 crashes immediately after startup. The renderer process becomes unresponsive within ~60 seconds of launch, even without any user interaction — just opening the app and entering an existing project triggers the freeze.
This is the same root cause as issue #30906 (renderer unresponsive due to synchronous CPU-intensive operations on the UI thread), but triggered through a different code path: Markdown AST traversal (marked.js walkTokens) rather than diff computation (Myers execEditLength).
The app was auto-updated from v1.15.13 → v1.17.3 → v1.17.7. v1.15.13 worked fine; the regression started with the v1.16.0 Electron update.
Key log evidence:
window.log (16:33:49):
renderer unresponsive { window: 'main', currentURL: 'oc://renderer/index.html' }
Unresponsive samples (9 total) — all stuck in synchronous Markdown rendering:
at B.walkTokens (main-BR8G9WSs.js:11645:5) ← marked.js sync AST walk
at session-composer-state-C0aC1gfR.js:3396:20 ← Promise.all waiting
→ Markdown → PacedMarkdown → Show component chain ← SolidJS reactive cascade
window.log (16:36:03) — second session, same pattern:
renderer unresponsive after only 57 seconds of uptime
at h → q → J → vn → heal → stream (session-composer-state)
→ Markdown component render via SolidJS createResource/createComputed
manifest.json: uptime=69.88s — app killed within ~70 seconds
server.log at crash time:
global event disconnected
Secondary (non-fatal) issues observed across all sessions:

• @opencode-ai/plugin@local install failure (every 30-120s retry loop)
• duplicate skill name: find-skills (3 locations)
• ghostty-vt warning: unimplemented mode: 25
• Occasional fetch terminated errors to siliconflow API

Plugins

None (default installation, no custom plugins)

OpenCode version

v1.17.7 (auto-updated from v1.17.3, originally v1.15.13) Electron 42.3.3 / Chrome 148.0.7778.218 / Node 24.15.0 Windows x64, NSIS installer at %LOCALAPPDATA%\Programs@opencode-aidesktop

Steps to reproduce

1. Install OpenCode Desktop v1.17.7 on Windows 10/11 x64
2. Open an existing project with chat history (any project with prior sessions)
3. Wait 30-60 seconds — no interaction needed
4. Renderer becomes unresponsive, window freezes, process killed after ~10s watchdog timeout
   This happens on EVERY launch, not intermittently. The app is unusable.

Screenshot and/or share link

window.log

window.log

Operating System

Windows 10 x64 (build 19045)

Terminal

N/A — using Desktop app, not TUI

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Desktop v1.16.0 Windows: renderer unresponsive / UI freeze when computing diff of large files #30906: Desktop v1.16.0 Windows renderer unresponsive / UI freeze (same root cause you referenced)
• Renderer unresponsive (freezes) with Solid.js findDOMIndex infinite loop - OpenCode 1.16.2 #31099: Renderer unresponsive with SolidJS infinite loop — similar freeze/crash symptoms
• Desktop app renderer freezes/crashes repeatedly #31594: Desktop app renderer freezes/crashes repeatedly
• Renderer freezes / "app not responding" when computing large diffs #32046: Renderer freezes / "app not responding" when computing large diffs

If your issue is distinct from these (e.g., triggered specifically by Markdown AST traversal via marked.js walkTokens rather than diff computation), please clarify the difference so maintainers can track it separately.

[ACbye]

This issue differs from the referenced ones in trigger path:

• Renderer freezes / "app not responding" when computing large diffs #32046: diff computation (Myers execEditLength) → not relevant
• Desktop v1.16.0 Windows: renderer unresponsive / UI freeze when computing diff of large files #30906 / Renderer unresponsive (freezes) with Solid.js findDOMIndex infinite loop - OpenCode 1.16.2 #31099 / Desktop app renderer freezes/crashes repeatedly #31594: same symptom (renderer unresponsive) but via SolidJS general reactivity

This issue is specifically triggered by Markdown AST traversal: marked.js walkTokens → PacedMarkdown → Show → stream → heal chain in session-composer-state. The call stack is 100% reproducible at every launch within 30-60 seconds, even with zero user interaction. Stack trace available in attached debug bundle.

Please keep this open as a distinct Markdown-rendering-specific renderer freeze.