test(cli): remove session cancellation timing races

[markijbema]

Why

The Windows unit job in PR #10388 failed in two session cancellation tests even though the corresponding Linux job passed. Looking across recent failed workflows showed both failures were intermittent and strongly correlated with loaded Windows runners:

• stops quickly when aborted during retry backoff failed when interrupt cleanup exceeded an internal 2-second wall-clock deadline.
• cancel with queued callers resolves all cleanly previously failed at its whole-test timeout and still used a fixed 50 ms sleep to assume the second caller had joined the active run.

Neither deadline is part of the behavior these tests need to prove. They make correctness depend on how quickly CI schedules Effect fibers and finalizers. Workflow reruns frequently pass without code changes, while the underlying cancellation assertions remain stable.

What changed

• Remove the inner timeout around compaction fiber interruption. The test still waits for the published retry status before interrupting, then verifies that the fiber exits through interruption. The outer test timeout still protects against a genuine deadlock.
• Replace Effect.sleep(50) with Effect.yieldNow before cancelling queued prompt callers. This gives the newly forked caller a scheduler turn without requiring it to complete within an arbitrary real-time window.

Why this preserves coverage

The behavioral assertions are unchanged:

• retry backoff must be interruptible and terminate with an interrupt cause;
• both callers sharing a prompt run must resolve successfully after cancellation;
• both callers must receive the same assistant message.

This removes timing assumptions rather than weakening the expected cancellation semantics. The lower-level runner suite also covers queued cancellation using observable runner state, so the prompt integration test remains focused on end-to-end behavior.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• packages/opencode/test/session/compaction.test.ts - Removed scheduler-sensitive inner timeout on compaction interrupt verification
• packages/opencode/test/session/prompt.test.ts - Replaced Effect.sleep(50) calls with Effect.yieldNow and waitFor + SessionStatus.Service readiness signals

Previous Review Summary (commit 670f2fa)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit 670f2fa)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• packages/opencode/test/session/compaction.test.ts - Removed scheduler-sensitive inner timeout on compaction interrupt verification
• packages/opencode/test/session/prompt.test.ts - Replaced Effect.sleep(50) with Effect.yieldNow for cooperative scheduler sync

Other Observations (not in diff)

Several remaining Effect.sleep(50) / Effect.sleep(20) calls in prompt.test.ts (lines 93, 1290, 1695, 1737, 1971, 1974, 2004) follow the same anti-pattern that was fixed on line 1237. Consider replacing these with Effect.yieldNow or proper readiness signals in a follow-up to reduce further CI flakes.

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_{Reviewed by deepseek-v4-pro-20260423 · 371,954 tokens}

_{Review guidance: REVIEW.md from base branch main}