fix(desktop): pin preview CDP debugger across webview teardown

[leoisadev1]

Problem

Heavy preview automation can SIGSEGV the desktop browser process. Electron's webContents.debugger wrapper is GC-managed but registered with Chromium as a raw pointer. Cleanup also re-read wc.debugger, which throws once the webview is destroyed, so detach was skipped.

Changes

Pin the debugger reference on each preview control session and route attach, detach, sendCommand, and color-scheme emulation through it. A new test destroys the webview getter and still expects detach.

Adapted from pingdotgg#9068. Preview artifact transfer remains with the remote-media worker.

Scope

This PR is debugger lifetime only.

Covered here:

• fix(desktop): preview CDP sessions no longer hard-crash the app pingdotgg/t3code#9068 preview CDP crash

Still assigned to this handoff, in later PRs:

• desktop shortcut isolation and editing chords (fix(desktop): isolate preview keyboard shortcuts from the host pingdotgg/t3code#9840 fix(desktop): preserve browser editing shortcuts pingdotgg/t3code#10621)
• desktop context menus (fix(desktop): enable context menus in the browser pingdotgg/t3code#10670)
• client incremental rollover / hidden rendering (perf(web): stop replaying terminal buffers on rollover pingdotgg/t3code#9707 perf(web): stop rendering hidden terminals pingdotgg/t3code#9718 perf(web): speed up terminal snapshots pingdotgg/t3code#9663 perf(web): avoid repeated terminal metadata scans pingdotgg/t3code#9747)
• terminal input (feat(mobile): paste the phone clipboard into the terminal pingdotgg/t3code#9199 fix(web): copy terminal selection with Ctrl+Insert pingdotgg/t3code#8541 fix(web): middle-click pastes in the terminal on Linux pingdotgg/t3code#11018 fix(web): honor terminal link browser overrides pingdotgg/t3code#10060)

Verification

• vp test run apps/desktop/src/preview/Manager.test.ts: 73 passed, including the destroyed-webview detach case.
• vp lint on the two files: no new errors.

Native Electron crash reproduction was not run on this Linux host.

Implemented and verified by Grok 4.6 High in Grok Build via Orca.

[vercel]

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1 Skipped Deployment

Project	Deployment	Actions	Updated
akeru-bot-landing	Skipped		Sep 10, 2026 5:51pm UTC

[greptile-apps]

Greptile Summary

This PR pins each preview control session's Electron debugger wrapper and consistently uses that retained reference for CDP attachment, commands, color-scheme emulation, listener cleanup, and detachment. This prevents cleanup from re-reading webContents.debugger after the webview has been destroyed.

• Adds the pinned debugger to BrowserControlSession.
• Routes control-session CDP operations through the pinned reference.
• Adds a regression test proving destroyed-webview cleanup still removes the listener and detaches.

Confidence Score: 5/5

The PR appears safe to merge, with the debugger lifetime fix consistently applied and covered by a focused teardown regression test.

No actionable failures remain; the retained debugger is used for attachment, command dispatch, listener cleanup, and detachment, while existing replacement cleanup prevents an old session from detaching its successor.

Important Files Changed

Filename	Overview
apps/desktop/src/preview/Manager.ts	Pins the Electron debugger wrapper for each control session and uses it consistently throughout the session lifecycle.
apps/desktop/src/preview/Manager.test.ts	Adds focused coverage showing that cleanup detaches through the retained debugger after WebContents access becomes invalid.

Sequence Diagram

sequenceDiagram
  participant M as Preview Manager
  participant W as WebContents
  participant D as Pinned Debugger
  participant C as Chromium CDP
  M->>W: Read debugger during session creation
  W-->>M: Debugger wrapper
  M->>D: Retain wrapper for session lifetime
  D->>C: Attach and send commands
  W--xW: Webview destroyed
  M->>D: Remove listener and detach
  D->>C: Detach without re-reading WebContents

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