fix(cli): make shell cancel race-safe with uninterruptible setup

[shssoichiro]

Shell cancel was flaky because the fiber could be interrupted before messages were persisted to the database, causing lastAssistant to throw "Impossible". Also, the finish cleanup only covered the spawn phase, leaving tool parts stuck in "running" state when the interrupt landed between setup and spawn.

Wrap setup in uninterruptibleMask and use acquireUseRelease to guarantee the finish release runs on every exit path, including immediate interrupts that arrive before the spawn phase starts.

How to Test

Run the following 3 tests, which are flaky in main, repeatedly in a loop:

cancel interrupts shell and resolves cleanly
cancel persists aborted shell result when shell ignores TERM
cancel interrupts loop queued behind shell

Expected behavior: 100% pass rate (observed on this branch)

Get in Touch

ExpedientFalcon on Discord

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 files)

• packages/opencode/src/session/prompt.ts

---

_{Reviewed by gpt-5.4-20260305 · 435,893 tokens}

[marius-kilocode]

Hi @shssoichiro thanks for the fix. But we are quite careful on any changes in this direction at the moment. We will take care of the test issues.