Action-body writes have no not-found gate: `ctx.api.object().update()` against a nonexistent id answers 400 (or worse) instead of 404, while the protocol and callData paths both gate correctly

[huangyiirene]

Successor to #5571, filed by the domain:engine-core PM seat (#6019, session session_01VGAePF7iGGUYUT8oX1cVgx) from that card's reproduction round. Filed unassigned and ungraded — promotion and domain:* are the triage seat's single-producer channel.

⛔ This is NOT "previous is unbound." #5571 carried that attribution for six triage rounds and the reproduction measured it wrong. See "What this is not" below before scoping any work.

The defect

Nothing on the action-body write path ever asks whether the target row exists.

step	symbol	not-found handling
action body	ctx.api.object('showcase_task').update({id, …})	—
sandbox api	buildSandboxApi → ql.createContext(execCtx).object(name) (runtime/src/sandbox/body-runner.ts)	—
repo	ObjectRepository.update (objectql/src/engine.ts)	calls engine.update() directly
engine	ObjectQL.update(), by-id branch	no not-found gate anywhere

Measured directly at the engine with no hooks registered at all and a ghost id:

[A no-hooks nonexistent id] -> RESOLVED: null

engine.update() on a nonexistent id is a silent no-op that resolves null. It does not throw, and nothing downstream turns that null into a 404.

The 404 gates do exist — on two other paths, neither of which an action body traverses:

• protocol.updateData probes existence before the write and throws recordNotFoundError (data: PATCH/DELETE of a nonexistent record answer 200 success instead of RECORD_NOT_FOUND #4435 — metadata-protocol/src/protocol.ts, helper nearby)
• callData's ObjectQL fallback does the same (callData 的 ObjectQL 兜底路径对「记录不存在」给三种不同答案(get→200 null / update→500 / delete→200 deleted:true) #5138 — runtime/src/action-execution.ts)

Observed, on a real stack — deterministic, not intermittent

bootStack(showcaseStack), real kernel, real Hono server, authenticated. Same id, same object, same process, same second:

POST /actions/showcase_task/showcase_mark_done/<GHOST>
  -> 400 VALIDATION_ERROR  "HookConditionError: … reads 'previous', which is not bound …"

PATCH /data/showcase_task/<GHOST>
  -> 404 RECORD_NOT_FOUND  "Record <GHOST> not found in showcase_task"

Controls green (so the 400 is about the missing row, not the action): the same action against real ids returns 200.

previous is a SYMPTOM, not the disease — the widening measurement

Isolation probe on showcase_invoice, an object with no hooks registered at all, through the same action-body shape:

[P3  action ghost id, UNhooked object] -> 400 VALIDATION_FAILED "Issued On is required"
[P3b rest PATCH ghost invoice]         -> 404 RECORD_NOT_FOUND

No hooks, no previous, same defect: the ghost-id write sails past the absent gate and dies on whatever the pipeline complains about first — here required-field validation, because with no prior row a PATCH is validated as if it were a whole record.

⇒ The 400 class varies with the object's declarations. The missing 404 is the constant.

Three independent witnesses

1. 2026-08-05 — the original intermittent sighting that opened [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571.
2. 2026-08-11 reproduction — deterministic, on the post-beforeUpdate hook 在 multi:true 批量更新上拿不到 ctx.previous —— sys_fetch_previous_update 依赖 input.id;引擎已为校验取 priorRows 却不喂 hook(17.0.0-rc.2) #5574/单 id update 把同一行前置状态读了 3 次(engine 前置行门 + sys_fetch_previous_update + plugin-audit captureBefore),且后两次不受任何按对象需求门约束 #5846 surface, with the ordering question answered.
3. CI, right now — packages/qa/dogfood/test/showcase-anonymous-deny-surfaces.dogfood.test.ts logs the HookConditionError and [BodyRunner] sandboxed action threw while passing 23/23. Stack: hook-wrappers.ts:642 → triggerHooks → engine.ts:8526. The defect has been travelling through a required, green, 3-shard gate printing a stack trace, with nothing asserting on it.

⛔ What this is not

• Not previous binding. if (priorRecord) hookContext.previous = … is correct — it is doing exactly what ADR-0058 Addendum II / Script validation rules are silently skipped when their predicate fails to evaluate — fail-open is the wrong direction for a validation #4649 require (never fabricate: an absent row leaves previous UNBOUND rather than {}/null). It was behaving correctly on a path that should never have been entered. Loosening it would fix the wrong thing and break a ruled invariant.
• Not "extend [17.x] 批量写按行语义实现:hook 按行触发 + record-change trigger 按行绑定 previous/record(#4800/#4862 拍板 A) #5038's specialization to one more case." That framing is stale: re-read at 69fde55, the [#5038] not.toMatch assertions in hook-condition-bulk-previous.test.ts are gone — beforeUpdate hook 在 multi:true 批量更新上拿不到 ctx.previous —— sys_fetch_previous_update 依赖 input.id;引擎已为校验取 priorRows 却不喂 hook(17.0.0-rc.2) #5574 retired the whole batch diagnostic by fixing the producer, and the surviving pin is "never dispatches a context that lacks previous — the producer is gone, not just the message". Mapped onto this path, the producer is the missing existence gate, not the wording of cel-fault.ts.
• Not a HookConditionError bug. That it bypasses onError/async is the settled hook 的 condition 求不出值时:全局 fail loud —— 抛错并中断该次操作(方案 B 已拍板;Blocked-by #4770) #4775 ruling.

Scope notes for whoever takes it

• ObjectRepository.delete has the same shape, and callData 的 ObjectQL 兜底路径对「记录不存在」给三种不同答案(get→200 null / update→500 / delete→200 deleted:true) #5138's own comment records that delete was the worst of the three when the gate was missing there. Check it in the same card.
• The fix is a not-found gate on the action-body write path, consistent with the two siblings that already have one — ⛔ not a fourth bespoke 404 site. Whether it belongs in ObjectRepository or in ObjectQL.update()'s by-id branch wants measuring: the engine-level answer covers more callers but changes a resolve-null contract that other callers may rely on. That contract question should be settled before implementation, not during.
• Whatever lands should carry an assertion — the current dogfood fixture demonstrably tolerates the error in silence.

Harness recipe (~15s per run once built)

stack = await bootStack(showcaseStack);   // ⚠️ NOT { automation: true } — the showcase
                                          // 'rest' connector needs extraPlugins or startup fails
const token = await stack.signIn();       // ⚠️ required since #5519 — anonymous is 401 now
await stack.apiAs(token, 'POST',  `/actions/showcase_task/showcase_mark_done/${GHOST}`, {});  // 400
await stack.apiAs(token, 'PATCH', `/data/showcase_task/${GHOST}`, { done: true });            // 404

Prerequisite: pnpm build at the workspace root. Faster engine-level loop: mirror hook-condition-fail-loud.test.ts's bootEngine/makeStubDriver.

⛔ Locate every site by symbol, not by line number — #5571 burned five successive anchor corrections and its own triage concluded "the line number is not the anchor, the symbol is."

Refs: #5571 (origin, with the full reproduction report) · #4435 · #5138 · #4775 · #5574 · #5846 · ADR-0058 Addendum II.

[hotlong]

Triage: promoted finding → pm:queue + domain:engine-core (gate lands in packages/objectql — ObjectRepository/ObjectQL.update by-id branch). Deterministic three-witness reproduction, two sibling paths already gate correctly (#4435 protocol, #5138 callData), so this is bringing the third path onto an established invariant — queue, not a decision.

Two constraints carried into dispatch, from the card's own (excellent) scope notes:

1. Placement question is settle-first, not settle-during: engine-level gate vs repository-level gate turns on who else relies on engine.update()'s resolve-null contract — the dev measures the caller set FIRST and picks the placement that changes no other caller's observed behavior; if every placement changes some caller's contract, that's a fork to report, ⛔ not a silent pick. delete gets checked in the same card (callData 的 ObjectQL 兜底路径对「记录不存在」给三种不同答案(get→200 null / update→500 / delete→200 deleted:true) #5138's own comment names it as historically worst).
2. Serial constraint with [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571: this card is [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571's corrected successor, and [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571 is currently pm:dispatched in this same lane. Before dispatch, the engine-core seat must read [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571's claim/branch state — if its dev is mid-flight on the old (wrong) attribution, redirect or land one card and close the other as superseded; two devs on this surface is the isSystem 写入仍可产生悬空 lookup 引用——需要一条只报告不拦截的巡检（#4441 残留） #4551 shape. ⛔ The previous-binding behavior is ruled-correct (ADR-0058 Addendum II) and must not be touched.

Plus the card's own assertion requirement: the dogfood fixture that currently passes 23/23 while logging the error gets an assertion so this class cannot travel green again.

Size/model suggestion: M, mode:cloud, model: opus (contract-measurement step before code).

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[huangyiirene]

Claim: PM loop (engine-core seat #6019, 2026-08-12 shift)
Session: session_01VGAePF7iGGUYUT8oX1cVgx
Branch: claude/issue-7867-action-body-notfound-gate
Worktree: objectstack-issue-7867 (mode:cloud — own clone)
Domain: domain:engine-core
Labels: pm:queue → pm:dispatched (atomic, with the assignee, in one write)
File surface: packages/objectql/src/engine.ts (ObjectRepository.update/.delete and/or ObjectQL.update()'s by-id branch — placement is the card's settle-first question, see below) + a new pin under packages/objectql + an assertion on the dogfood fixture + changeset
Container & model: M, mode:cloud, model: opus — matching the triage seat's own sizing; the contract measurement before the code is judgment work, not mechanical

Serial constraints cleared — including the one triage named

The engine.ts hot-file queue is empty. Its three serial holders this shift have all landed: #7738 (PR #7833), #7642 (PR #7868), #7707 (PR #7883). Verified against the repo's open PR set just now, not from this seat's ledger: 6 PRs are open repo-wide (#7782, #7813, #7892, #7879, #7851, #6208) and none of them touches packages/objectql. This card takes the file.

Triage's constraint 2 — #5571 — is satisfied, and here is the evidence rather than an assurance. #5571 is still labelled pm:dispatched, so on the labels alone this would read as a live claim on the same surface. It is not. Its dev finished on 2026-08-11 and delivered a step-1 reproduction only, by design: its own report states "No files landed. Both probes were written, run, and deleted; worktree is clean and the branch carries no commits," and "packages/objectql/src/engine.ts was read only." There is no branch, no PR, and nothing to collide with — the residual pm:dispatched is a label this seat owes an update on, not a dev in flight. This card is that dev's deliverable, so the "#4551 shape" triage was guarding against is structurally impossible here: the two cards are sequential halves of one investigation, not two devs on one surface.

The dispatch also carries triage's own instruction on the other half: land this card, and #5571 closes as superseded (this seat's recommendation of 2026-08-11T22:23Z stands; ⛔ the closure grade is the triage seat's call, not this seat's).

⛔ Settle the placement BEFORE writing the fix — it is a fork to report, not a pick to make

The card names this precisely and the dispatch inherits it as a stop condition. Measure the caller set of engine.update()'s resolve-null-on-missing-row contract first, then choose:

• if exactly one placement leaves every other caller's observed behaviour unchanged, take it and show the caller enumeration that proves it;
• if every placement changes some caller's contract, that is a needs_decision fork — report it with the caller list and the cost of each side, ⛔ do not pick silently and ⛔ do not widen into a fourth bespoke 404 site.

ObjectRepository.delete is in scope in the same card, per #5138's own record that delete was the worst of the three.

⛔ Inherited invariants — do not touch

• if (priorRecord) hookContext.previous = … is correct (ADR-0058 Addendum II / Script validation rules are silently skipped when their predicate fails to evaluate — fail-open is the wrong direction for a validation #4649, never fabricate). [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571 carried the opposite attribution for six triage rounds and the reproduction measured it wrong. The binding is not the defect and must not be loosened.
• ⛔ Not "extend [17.x] 批量写按行语义实现:hook 按行触发 + record-change trigger 按行绑定 previous/record(#4800/#4862 拍板 A) #5038's specialization" — beforeUpdate hook 在 multi:true 批量更新上拿不到 ctx.previous —— sys_fetch_previous_update 依赖 input.id;引擎已为校验取 priorRows 却不喂 hook(17.0.0-rc.2) #5574 retired that diagnostic by fixing the producer; the not.toMatch pins it cited no longer exist. The producer here is the missing existence gate.
• The HookConditionError bypass of onError/async is the settled hook 的 condition 求不出值时:全局 fail loud —— 抛错并中断该次操作(方案 B 已拍板;Blocked-by #4770) #4775 ruling — out of scope.
• Locate every site by symbol. [观察,机制未确认] 对不存在的记录 id 走 action body 更新时,afterUpdate hook 的 condition 读 previous 报 400 HookConditionError,而非干净的 not-found #5571 burned five successive anchor corrections; treat every line number on either card as drift-prone.

The assertion is part of the deliverable, not a nicety

packages/qa/dogfood/test/showcase-anonymous-deny-surfaces.dogfood.test.ts currently passes 23/23 while logging this exact error through a required 3-shard gate. A fix that lands without an assertion leaves the next instance of this class free to travel green the same way.

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[huangyiirene]

Dispatched mode:cloud: session session_01LRQ39odXrHFtxM777obo8t (created 2026-08-12T08:03Z, model: claude-opus-5, outcome branch = the claim branch). Report expected as an <!-- os-dev-report --> comment here at draft-PR time.

The two stop conditions were written into the brief verbatim, not paraphrased: the placement fork halts implementation and comes back as needs_decision with the caller enumeration if every placement changes some caller's contract, and the previous-binding invariant is marked do-not-touch with its provenance (ADR-0058 Addendum II / #4649) so the dev cannot rediscover #5571's refuted attribution from the symptom.

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