fix(responses): bound body inactivity without premature shared abort

[luvs01]

Summary

Reimplements the combined response-body inactivity work tracked in contributor fork PR/issue 176 (contributor fork PR 176), including the direct-passthrough scope and terminal-ordering finding from contributor fork PR/issue 339 (contributor fork PR 339), on the refactored current Responses pipeline. This is a new implementation, not a claim that either old proposal was merged or that its old tests validate this head.

• Add a body-local, pending-read inactivity guard with highWaterMark: 0. Non-empty bytes pause the deadline; empty chunks cannot reset it, including a microtask-only empty producer. Slow downstream consumers do not consume the upstream inactivity allowance. Large timer values avoid signed-32-bit timer overflow.
• Guard direct native bodies and returned redirect bodies after native delivery classifies them, outside its relay/lifetime wrappers. Preserve the original Response object for native SSE (including the missing-Content-Type fallback), bounded JSON, and error readers. Native SSE keeps its existing watchdog and terminal owner; no second watchdog is stacked in front of the eager relay.
• Scope both streaming and buffered HTTP adapter parsers, including each successful terminal-guard/empty-completion continuation. Retry/status classification remains before parsing, so backoff and unread retry-body cleanup do not share a newly armed body deadline. Existing retry/authentication/routing policy is unchanged.
• On timeout, publish a typed read failure and cancel only the current body's reader; do not abort the request-wide controller before the enclosing bridge can deliver its failure terminal. EOF, external abort, early parser return/throw and iterator abandonment release the reader and timer/listener without awaiting broken cancellation cleanup. Buffered initial timeouts become HTTP 504; continuation timeouts produce an error event with status 504; caller cancellation retains 499.
• Add 29 focused regression cases to the already registered tests/lib/abort-idle-deadline.test.ts and document the contract in structure/transports/streaming-health.md. The existing six idle-deadline tests are preserved. No new setting, dependency, workflow or permission change.

Current head: eef5364ff3fdbe236aa3d61b4e80c26b63b5c740 (tree 4569a2ab3abeb8709a248e752b4a156be8c35f33), integrating dev through 9052ddf7. This head merges the latest dev with no conflicts; the PR-side tree is unchanged by the merge except incoming dev content (the dev-side budgetOwner helper extraction in tests/responses/responses-core-modules.test.ts).

The current commit corrects only a source reference in the initial commit message: both original PR references now explicitly name the contributor fork. The six-file tree is unchanged (6451a3a7a66fc92d7266ccd9ddbce636685a703b); all code/test evidence below applies to that identical tree. This does not claim contribution from the unrelated upstream PR with the same number.

Verification

Completed in the available Node 22.16.0 environment:

• 29/29 new deterministic regression cases passed, using the actual TypeScript helper with Node type stripping and a temporary harness that changes only the test-runner import and helper import path. This is explicitly not a Bun test result. Covers headers-only and mid-body stalls, empty chunks, backpressure, cancellation/EOF ordering, locked-reader cleanup, never-settling/rejecting cancellation, parser abandonment, a drained terminal in a minimal enclosing relay, native Response identity, redirects and long deadlines.
• 6/6 isolated pipeline component checks passed: the exact changed function bodies for streaming/buffered continuations, continuation cancellation, initial buffered delivery, native SSE identity and direct-body attachment. Unrelated imports were stubbed for these checks. They are not full-server or real-provider integration tests.
• 3/3 loopback HTTP scenarios passed with real Node fetch: headers-only silence; slow consumption followed by a mid-body stall; caller abort while the reader is locked.
• Node type-stripping syntax checks passed for all four changed/new runtime files and the test file. This is not TypeScript typechecking.
• All five existing-file baselines were reconstructed from GitHub reads and checked against their exact upstream Git blob SHAs before editing. All six published blob SHAs match the final local files.
• git diff --cached --check, forward git apply --check against the verified sparse baseline, and reverse patch checking passed. The sparse fixture is not represented as a complete repository checkout.

Repository gates on this head: bun run typecheck, bun run structure:check, bun run privacy:scan and the file-size ratchet pass locally, and bun test tests/lib/abort-idle-deadline.test.ts tests/server/terminal-guard-server.test.ts is 49 pass / 0 fail. The Node-only evidence above described the original authoring container and is kept for provenance; it is not the basis for the checklist.

Cross-platform CI on this exact head is run 35150861010 (diagnostic run 35150861010, contributor fork Actions). Every sharded lane passed: Linux 4/4, macOS 2/2, Windows 6/6, gates, storage policy, API usage, keyring on three platforms, docker smoke and npm-global on three platforms. The unsharded macos control diagnostic was cancelled at its own 30-minute cap while the fork queue was saturated, and the aggregate ci job fails only because of that cancellation. Its single failing case, BUG-R86 routed web-search timeout semantics > fast headers plus raw byte progress can outlive connectTimeoutMs, is a 1,000 ms test-level budget on a loaded runner; it passes in about 76 ms locally on this head and in every sharded lane of the same run. No workflow policy, permission, approval requirement or gate script was changed.

• Head ce35cdc9c: merged dev 6d19a07 cleanly; gates pass; focused tests 61 pass / 0 fail (324 assertions). Fork CI run 35218067709 (diagnostic run 35218067709, contributor fork Actions) completed with every lane green except the known macos control 30-minute dispatch cap (aggregate ci fails only on that cancellation).
• Current head eef5364ff: merged dev 9052ddf7 cleanly (zero conflicts; 80 files of incoming dev content, none overlapping this diff). bun x tsc --noEmit, bun run structure:check, bun run privacy:scan pass; the same three focused test files are 61 pass / 0 fail (335 assertions). Fork CI run 35238601699 (diagnostic run 35238601699, contributor fork Actions) completed on this head, green on every lane except the known macos control 30-minute dispatch cap.

Suggested first repository checks: bun test tests/lib/abort-idle-deadline.test.ts, the affected Responses/continuation/passthrough suites, bun run typecheck, bun run privacy:scan, and bun run structure:check; complete the full review-ready gate afterward. Native terminal-repair/eager/tee behavior and admission-lifetime cleanup still need full integration verification on this exact head.

Author review follow-up — 2026-09-17

Two CodeRabbit findings are fixed in 527393ffa09b3a2d46a0584de2263624cb47ec0e, both with red-to-green regressions:

1. The continuation catch block classifies the thrown error before reading signal state, so a source cancellation that synchronously aborts the shared signal no longer reports a body stall as client cancellation 499. tests/server/terminal-guard-server.test.ts drives a continuation body that never yields bytes and whose cancel() aborts the caller signal in the same tick.
2. Discarded zero-byte chunks yield to the macrotask queue every 64 reads without resetting the deadline, so a large configured timeout cannot starve timers. tests/lib/abort-idle-deadline.test.ts asserts a queued setTimeout(..., 0) runs at about 51 ms instead of 5,003 ms under a microtask-only empty producer.

structure/transports/streaming-health.md now records the classification order, the yielding rule, and that connect/stall and body-silence budgets read the same stallTimeoutSec in different phases, as the maintainer review asked.

Author review follow-up — 2026-09-17 (second pass)

Two further CodeRabbit findings are fixed in 39941c136ccf4d12277890a3b6e3777afdd9a045:

1. A ResponseBodyInactivityError thrown by the initial stream now maps to a terminal {type:"error", status:504, errorType:"upstream_error"} event instead of escaping to the bridge catch as a 500 proxy_error, matching the buffered path and continuation mapping. Covered by a new terminal-guard-server.test.ts regression asserting response.failed once with upstream_error and no proxy_error.
2. A passthrough regression case was added for a 200 text/plain body: inactivity error, source cancel propagation, unlocked reader and zero residual timers are asserted.

Verification on this head: bun test tests/lib/abort-idle-deadline.test.ts 37 pass, tests/server/terminal-guard-server.test.ts 14 pass, tests/responses/responses-core-modules.test.ts 10 pass, bun x tsc --noEmit clean. Fork CI on the new head is running: diagnostic run 35204662874 (contributor fork Actions).

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults. No credential, routing or authentication behaviour changes.

Summary by CodeRabbit

• New Features

  • Added inactivity protection for upstream response bodies across streaming, buffered, continuation, and direct passthrough responses.
  • Stalled reads now return a 504 error, while caller cancellations continue to return status 499.
  • Stall timeouts are applied consistently while preserving response content, headers, and status.
  • Native SSE, JSON, redirects, and non-OK responses retain their existing handling.

• Documentation

  • Documented inactivity handling, timeout behavior, cancellation, and supported response types.

• Tests

  • Added coverage for timeout boundaries, cancellation, metadata preservation, parser cleanup, and edge cases.

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📝 Walkthrough

Walkthrough

The change adds inactivity-aware response-body guards, applies them to passthrough, delivery, and continuation reads, maps stalled bodies to status 504, preserves cancellation status 499, and adds deterministic regression coverage.

Changes

Response body inactivity protection

Layer / File(s)	Summary
Inactivity guard and lifecycle handling src/lib/response-body-inactivity.ts, tests/lib/abort-idle-deadline.test.ts	Adds guarded response streams, direct passthrough exclusions, buffered and streaming parser wrappers, local cancellation, monotonic deadlines, and cleanup handling. Tests cover timeout boundaries, empty chunks, aborts, cancellation, parser failure, identity preservation, overflow-safe deadlines, and disabled deadlines.
Adapter delivery and continuation handling src/server/responses/adapter-delivery.ts, src/server/responses/adapter-continuation.ts, tests/server/terminal-guard-server.test.ts	Applies stallTimeoutSec to buffered and streaming response parsing. Body inactivity produces status 504. Client or upstream cancellation retains status 499. Unsupported parsing cancels the response body.
Passthrough wiring and documented flow src/server/responses/passthrough-execution.ts, structure/transports/streaming-health.md, tests/responses/responses-core-modules.test.ts	Wraps the delivered direct response after delivery and outside relay/lifetime wrappers. The guard uses the upstream signal and resolved timeout. Documentation and lease-order assertions describe and verify this sequence.

Priority: ⬇️ Low

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Bug fix

Merge Risk: 🔵 Low · up to 52739

An initial streaming body stall is reported as a generic 500 rather than a 504 timeout. This is bounded but should be corrected before merge.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 77.78% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 9 functions across 7 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding response-body inactivity bounds while avoiding premature abortion of the shared request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 77.78% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 9 functions across 7 files. (1 skipped: 1 unsupported.)

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

⚠️ Deterministic hygiene checks failed.

• missing_coauthor_credit — This pull request says it reimplements, supersedes, carries, or rebases another author's pull request, but no Co-authored-by trailer names that author. Prose in a commit body is not read by anything; the trailer is what GitHub counts. Add it to the description or a commit, or obtain attribution-approved. Paths: #339.

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✅ READY

• all PR quality gates passed.

Hygiene

✅ Deterministic PR hygiene checks passed.

[lidge-jun]

리뷰 · 우선순위 76 / 80

이 PR은 Responses 파이프라인에서 업스트림 본문 inactivity(침묵) 을 잡되, 공유 AbortController를 먼저 죽여 터미널을 삼키지 않게 합니다. 지금 dev(b3035fe)의 adapter-continuation.ts/adapter-delivery.ts는 cancelBodyOnAbort로 클라이언트 abort만 본문에 연결하고, pending-read 침묵 데드라인은 없습니다. 이 PR은 새 src/lib/response-body-inactivity.ts에서 리더 하나를 소유하는 가드를 만들고, highWaterMark: 0으로 소비자가 멈춘 동안 추측 read를 하지 않습니다. 빈 청크는 progress로 치지 않고 데드라인을 리셋하지 않으며, 큰 timeout은 signed-32bit setTimeout 오버플로를 피하려고 남은 시간을 잘라 arm합니다. 타임아웃은 공유 signal을 abort하지 않고 로컬로 fail한 뒤, 어댑터 경로가 504/에러 이벤트를 내게 합니다. 네이티브 SSE·이미 분류된 JSON/에러는 guardDirectPassthroughBodyInactivity가 건드리지 않고, passthrough는 delivery 이후 남은 direct body만 감쌉니다. draft·base dev입니다.

테스트 tests/lib/abort-idle-deadline.test.ts가 두껍고(약 474줄), structure/streaming-health.md에 계약을 적습니다. pre-split 모놀리스 경로를 다시 키우지 않고, 이미 쪼개진 responses/*에만 연결합니다. resolveStallTimeoutSec(config.stallTimeoutSec)*1000을 body inactivity에 재사용하는 점이 운영상 핵심입니다 — connect/stall과 body silence가 같은 손잡이를 쓰므로, 문서에 “같은 값·다른 국면”을 분명히 해 두는 게 좋습니다.

src/lib/response-body-inactivity.ts guardResponseBodyInactivity - 타임아웃 시 output.error 후 cancelSource. dispose는 parser 조기 반환/abandon도 정리. microtask-only empty producer 루프도 monotonic deadline로 끊음.
adapter-delivery.ts / adapter-continuation.ts - parseStream/parseResponse를 inactivity 래퍼로 감쌈. ResponseBodyInactivityError → 504. continuation은 공유 signal abort 없이도 에러 yield 가능해야 한다는 주석이 핵심.
passthrough-execution.ts - deliver 이후 guardDirect… . SSE/JSON/redirect/!ok는 스킵. 릴레이 prefetch가 inactivity clock을 건드리지 않게 “바깥”에 둔 설계는 맞음.
cancelBodyOnAbort 제거(continuation) - inactivity 가드가 abort listener를 포함. adapter-dispatch 등 다른 경로는 기존 cancelBodyOnAbort가 남아 있는지 CI에서 회귀 확인 필요.
draft + 본문 고지 - 호스티드 Bun/전체 스위트는 이 환경에서 미실행. tip CI가 필수.

메인테이너의 판단이 필요한 지점

• stallTimeoutSec 한 손잡이를 body inactivity에도 쓸지, 별도 설정을 둘지.
• draft 해제 전 최소 게이트(typecheck + responses/lib 관련 테스트) 범위.
• fix(server): retain raised inbound body admission through HTTP lifetime #4753(inbound admission)과 동시에 올릴 때 HTTP 래퍼 순서 충돌이 있는지(보통 독립).

너의 추천
draft 해제·tip CI 통과 후 KEEP → 머지하세요. stall 손잡이 공유는 문서 한 줄만 보강하고, 별도 설정은 실제 운영 불만이 나오기 전엔 만들지 마세요. 지금은 KEEP.

이 댓글은 grok-bot이 작성했습니다

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Actionable comments posted: 1

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Inline comments:
In `@src/server/responses/adapter-continuation.ts`:
- Around line 499-502: In the terminal continuation error classification, check
whether the caught error is a ResponseBodyInactivityError before inspecting
options.abortSignal or upstream.signal, so timeout failures consistently yield
status 504 even if cancellation synchronously aborts the upstream signal.
Preserve the existing status-499 mapping for non-timeout aborts and the current
error event contract.

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• src/lib/response-body-inactivity.ts
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• src/server/responses/adapter-delivery.ts
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Inline comments:
In `@src/lib/response-body-inactivity.ts`:
- Line 110: Update the empty-chunk handling in the ReadableStreamDefaultReader
loop around source.getReader() so discarded zero-byte chunks periodically yield
to the event loop without resetting the inactivity deadline or treating them as
progress. Extend the regression test to verify that another queued task executes
before the inactivity deadline.

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• src/lib/response-body-inactivity.ts
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In `@src/server/responses/adapter-delivery.ts`:
- Around line 74-78: Wrap the initial stream created in the initialEventStream
flow with async-generator error handling. Convert ResponseBodyInactivityError
from readResponseStreamWithInactivity into a single adapter error event with
status 504 and upstream_error, then stop iteration; rethrow all other errors
unchanged before passing the stream to the existing guards.

In `@tests/lib/abort-idle-deadline.test.ts`:
- Around line 546-558: Add a fake-clock test case alongside the existing
passthrough guard tests for a successful 2xx response with a plain non-SSE,
non-JSON content type. Exercise guardDirectPassthroughBodyInactivity, then
assert ResponseBodyInactivityError on body consumption, source cancellation, an
unlocked source, and no pending timers.

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[luvs01]

Merged the latest dev (6d19a07) into the PR branch — zero conflicts; new head ce35cdc. Local gates pass: �un run typecheck, �un run structure:check, �un run privacy:scan; focused tests �un test tests/lib/abort-idle-deadline.test.ts tests/server/terminal-guard-server.test.ts tests/responses/responses-core-modules.test.ts are 61 pass / 0 fail. Fork CI dispatched and in progress: diagnostic run 35218067709 (contributor fork Actions)

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[luvs01]

Absorbed latest dev (9052ddf7) — clean merge, new head eef5364ff (tree 4569a2ab3). Gates pass on the merged head (typecheck, structure, privacy) and the three focused test files are 61 pass / 0 fail. Fork CI: diagnostic run 35238601699 (contributor fork Actions) (in progress; the macos control dispatch job is expected to cancel at its 30-minute cap — see #4905). Checklist is fully ticked and the PR is out of draft.

[lidge-jun]

macos 1/2 reported cancelled, and the aggregate correctly refused to call that a pass — platform-macos was requested by pull_request but reported 'cancelled'.

It is a budget overrun, not a failure and not a defect in this branch: the job ran 09:47:34 to 10:07:50, which is 20m16s against the 20-minute platform-macos budget. The cause is contention I created by approving nine Cross-platform runs at once; this account runs one of them at a time, and the same shard completed inside the budget earlier today on dev and on #4926 and #4938.

Re-running the failed job rather than widening the budget. Widening it would buy green by agreeing to stop noticing a shard that is genuinely wedged, which is the distinction #2152 and #4956 exist to keep.

[lidge-jun]

macos 1/2 failed on a test that is not in this branch's scope, and I do not think it is this branch's defect:

(fail) Codex history injection preflight on a WAL store with no live writer >
       reaches a verdict on a cleanly-closed WAL store rather than the catch-all refusal
Received: "history_injection_preflight_unavailable"

That case is tests/codex-integration/codex-history-provider.test.ts:1676, and this branch touches response body inactivity and adapter continuation/delivery — nothing that reaches SQLite or the history preflight.

Two mundane explanations are ruled out by reading the file. Test isolation holds: the file-level afterEach calls setStateDbPreflightOpenFailureForTests(undefined), and this case installs no hook of its own. Sidecar state holds too: checkpointedWalFixture removes both -wal and -shm after closing, which is exactly the condition openCodexStateForPreflight requires before admitting the immutable fallback.

What is left is the error classification. The fallback is gated on isStateDbCantOpenError, and an error that predicate does not recognise is rethrown into the preflight's catch-all — which is the value observed. #4943 already fought this platform's disagreement about when the missing shared memory is raised; this looks like a disagreement about what it is raised as, on at least one macOS runner state.

Re-running the failed job. I am tracking it separately rather than treating it as noise: a macOS-only nondeterministic preflight verdict is a flake, and the same file passed on dev earlier today in the same shard.

[lidge-jun]

Rebased onto current dev (9939b884f0) and force-pushed. The merge base was 50d72a1d09, so this branch was testing a merge preview several hours and a dozen merges behind.

Correcting my earlier note: the WAL preflight failure reproduced on the re-run, so it is not a flake in the sense I described. It is deterministic for this branch's merge preview and does not reproduce on dev, whose own macos 1/2 is green at the same time. Staleness is the first thing to rule out, which is what the rebase does.

The second failure in that run, GET /api/system/memory ... (#848) at 20249ms, is a timeout under the macOS contention I created by approving nine Cross-platform runs at once, and should clear on its own.

[lidge-jun]

Green after the rebase, which settles the diagnosis: the Codex history injection preflight ... reaches a verdict on a cleanly-closed WAL store failure was the stale merge preview, not this branch and not the macOS runner. It reproduced twice against a base twelve merges old and does not occur against current dev.

Merging. Bounding body inactivity without tearing down the shared abort is the right shape — a stalled body is a property of one response, and cancelling the request's shared signal for it takes down work that is still healthy. Mapping the initial stall to a 504 rather than a generic failure matters for the same reason the budget refusal maps to 429 elsewhere in this tree: the status a client retries on has to match what actually went wrong.