ui-server: the host-token-fallback budget tests race a 200 ms adapter window against the worker commit

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
74/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
bun, sqlite, typescript
Domain
testing

Research direction

Start with packages/ui-server/tests/ws-turn-budgets.test.ts around lines 58 and 66, then read packages/ui-server/src/brain/turn-budgets.ts to understand when the budget report settles and the host aborts. Replace the fixed 200 ms wait with a wait for the abort decision that has a long deadline. Run the test repeatedly; it should pass under load and fail if the host abort is removed.

Written by the indexing model from the issue text.

Description

agent-ready area: ui-server type: test

Context

ws-turn-budgets.test.ts's "actual claude/pi completed response crosses the host token fallback and stops with budget_exceeded, preserving partial work" cases fail intermittently with BUDGET_HOST_ABORTS_ACTUAL_ADAPTER (expected true, received false).

The fixture adapter waits for the host's abort for at most 200 ms after emitting usage that crosses the budget: Bun.sleep(200) in the Promise.race after each fixture adapter emits its usage, packages/ui-server/tests/ws-turn-budgets.test.ts:58 (Claude) and :66 (Pi). Since #2896 the blocking budget report commits on the SQLite write worker (observe, packages/ui-server/src/brain/turn-budgets.ts), and the host aborts only once that commit settles. On a loaded host the commit plus the abort can take longer than 200 ms, so the adapter returns first and the test reads it as "not aborted".

Observed on 2026-10-26, running the file alone on a loaded shared host:

  • main c47483196: 2 failures in 22 runs;
  • an unmerged #2850 slice branch: 6 failures in 33 runs.

The full ui-server suite also failed both cases once.

Scope

Make the test wait for the host's abort decision rather than a fixed 200 ms. For example, the adapter could hold until the budget report has committed (budgets.settled() or an equivalent hook) or the turn's abort signal fires, with a long deadline. The test must still prove that the host aborts the adapter, and fails if it never does.

Out of scope

Changing how or when the host aborts a turn over budget.

Acceptance criteria

  • The file passes 20 consecutive runs on a host under three dd … conv=fsync writers.
  • A mutation that removes the host's budget abort still fails BUDGET_HOST_ABORTS_ACTUAL_ADAPTER.

Verification

bun run test packages/ui-server/tests/ws-turn-budgets.test.ts, repeated.

Contract impact

None.

Dominant language
TypeScript
Stars
3
Forks
0
Avg merge
5h 8m
Merged PRs (30d)
946

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  4. Open a pull request that references the issue number.

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