Desktop crash: pasting ~270KB text into prompt hangs renderer (JSON.stringify on main thread) #51988

Summary

opencode Desktop hangs ("renderer unresponsive", then crash) when pasting a large text (~277 KB, ~1500 lines) into the chat prompt input in one go.

Environment

• App: opencode Desktop 1.18.31 (packaged, win x64)
• OS: Windows x64
• Reporter: via Meta Muse Spark agent session

Repro

1. Open opencode Desktop, start a session.
2. Copy ~277 KB of plain text (in my case: 1503 lines / 276,765 bytes of Docker pull JSON progress log) and paste it into the prompt input at once.
3. The renderer hangs almost immediately ("renderer unresponsive"), and the app has to be killed / crashes.

Evidence (from exported debug logs)

desktop/.../window.log captured the hang with stack samples, all inside the paste path:

[error] (window) renderer unresponsive { window: '...', currentURL: 'oc://renderer/index.html' }
...
at HTMLDivElement.onPaste (main-mfFBJ4oT.js:129605:66)
at HTMLDocument.eventHandler ...
at PromptInputV2._el$6.$$input ...
at Object.onInput ...
at Object.setPrompt ...
at JSON.stringify (<anonymous>)

So each onInput from the paste runs setPrompt → synchronous JSON.stringify of the prompt/editor state on the renderer main thread. With ~270 KB of pasted text this blocks the main thread long enough for the renderer to be flagged unresponsive and die. No minidump is produced (Crashpad dir empty) — consistent with a main-thread hang rather than a native crash. renderer.log shows only unrelated ResizeObserver noise.

Expected

Large pastes should not kill the app — e.g. debounce/coalesce input handling, move prompt serialization off the critical path (or off the main thread), and/or cap single-paste size with a graceful warning.

Attachments (will upload manually)

• opencode-debug-20260929T021055.zip (exported debug bundle: main/window/renderer/crash logs)
• The exact pasted content (~277 KB Docker pull log) that triggered it

opencode-debug-20260929T021055.zip

内容.txt