[PR] fix: fork prefix gate is advisory — adopt drifted fork children with a classified warn (#3741) by ranxianglei · Pull Request #3757 · ranxianglei/billion-context

ranxianglei · 2026-10-19T01:24:11Z

ai: zhipuai-lb/glm-5.3

Fixes #3741(保守档,基于已合并的 #3743 分类诊断实现,owner 在 #3741 拍板)。

一句话:fork 子会话的首请求与继承前缀不匹配时,不再 409 卡死——照常收养,打一条带分类的 warn。

为什么拆这扇门

409 是永久死胡同:被拒首请求不计入 stats.requests → 每次重试都重新撞同一扇门,没有任何清除/TTL/自愈路径。This run failed with 409: "first child request does not match its inherited ordered prefix" | 本轮运行失败409 "first child request does not match its inherited ordered prefix" #3741 实报:dsh fork 子会话在代理原地升级换代(The intermediate message (core) is not protocol-agnostic: switching protocols/models causes identity churn; cross-protoc | 中间消息(core)没有做到协议无关:切协议/切模型制造身份 churn,补齐跨协议映射 #3642 canonical id re-key)后确定性卡死。
它不提供独有保护:唤醒子会话的真路由是 session-id 绑定(recordPluginSession → resolveConversation);字节级前缀校验只是唤起后的附加安检,其保护面(历史漂移)由每轮 resent history 的 fold reconcile(Snapshot as session reconstruction: identity claim order takes priority, message hash demoted to reference signal (root- | 快照即会话重构:身份认领顺序优先,消息哈希降级为参考信号(根治 #3588/#3640 一类误判) #3641 order-over-hash)完整覆盖。
代价可接受:漂移子会话的首请求未折叠全文出站=一次性 token 峰,正确性无损;后续轮 reconcile 拉平。

改动(src/server/handle.ts,净 -6 行)

receipt 块:verdict 不 ok 且 requests===0 → 原 409 分支改为 loggerLog warn + return true 收养;warn 带 [PR] fix: classify FORK_PREFIX_CONFLICT rejections instead of failing blind (#3740) #3743 分类 reason(id-drift / hash-drift-under-same-id / prefix-longer-than-incoming 等)+ protocol
publicForkPrefix 漂移时保持 false:side-lane 降级启发照常发言,不让未经证实的前缀一票否决
门保持 one-shot:首请求后 stats.requests>0 自然绕过,不重复检查

测试(tests/plugin-fork.test.ts 翻转,48/48 绿)

三种漂移形态(语义改写/重排/过短重放)全部:200 + 转发增长 + 父会话 parentRevision 不动 + 子会话 revision 前进 + 恰一条 warn(one-shot 语义钉死)+ 后续请求正常。dsh-fork-adopt 42/42、pi-omp-fork-adopt 含在内全绿,tsc 干净。

…a classified warn (#3741) The ordered-prefix 409 was a permanent dead-end: the rejected first request never incremented stats.requests, so every retry re-hit the same gate with no clear or TTL path (field report: dsh fork child stuck after an in-place proxy upgrade re-keyed message ids, #3642 canonical re-key generation). Routing is the session-id binding (recordPluginSession -> resolveConversation); the byte-exact pre-gate added no correctness fold reconcile (#3641 order-over-hash) doesn't already enforce — it only produced unrecoverable 409s. Now: mismatched first request is adopted, logs one classified warn (#3743 reason taxonomy), publicForkPrefix stays false so the side-lane demotion heuristics keep their normal say. Cost: a divergent child's first request goes out unfolded — a one-time token spike, never corruption. Gate stays one-shot (stats.requests > 0 bypasses it).

github-actions · 2026-10-19T01:25:23Z

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Branch: fix/fork-prefix-advisory (af61c62)

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…3757 review) The HASH PARITY CONTRACT still described the pre-#3757 behavior (409 FORK_PREFIX_CONFLICT, permanently poisoned child). A mismatched first request is now adopted with a classified warn; the real cost of hash drift is losing the verified-prefix fast path plus one unfolded first request.

#3757 review) Inverting the 409 sub-cases removed the only coverage of the hash-drift-under-same-id and ref-broken verdict branches (including #3743's fix that a pruned ref reports ref-broken alone, never hash-drift). Pin both directly against publicForkInputCheck with negative assertions so a future classifier regression cannot ship silently behind the advisory warn.

…review) lane-guard pairing for the handle.ts lane-adjacent edit, with real coverage: a drift-mismatched first request that is a declared side call (dsh title-gen shape) must be adopted AND still diverted to the #388 passthrough without touching child kernel state — reachable only after the gate stopped rejecting.

ranxianglei · 2026-10-19T01:44:56Z

🤖 Powered by ework · qwen3.8-27b

(ai: vllm-qwen/qwen3.8-27b)

查重：不重复。 独立复核：按 fork prefix / FORK_PREFIX_CONFLICT / adoption 检索 open+closed issue——只有已关闭历史家族（#2399/#2403/#2625/#2394/#2383）、已合并的诊断 PR #3743、本 PR；近期 15 个 open PR 无一触碰 fork 门或 side-lane 区域（#3745 标题里的「(#3741)」是平台编号撞车，那条是 delegate-wait 措辞，不相关）。

标签： bug / dsh / pi / opencode / scope/kernel / p2 —— fork 子会话卡死是真实缺陷家族，机制在会话核心的 fork 继承路径；受影响宿主是全部三个 plugin fork 家族（dsh/pi/opencode）；整体可用但个别会话永久死掉、可新建绕行 → p2（与 #3743 triage 一致）。

审核结论（八问）

是什么问题：fork 子会话的首请求与继承前缀不一致时被 409 拒绝，且这个拒绝是永久的——被拒请求不计入会话请求计数，每次重试都重新撞同一扇门，没有 TTL、没有自愈路径。现场案例（This run failed with 409: "first child request does not match its inherited ordered prefix" | 本轮运行失败409 "first child request does not match its inherited ordered prefix" #3741）：代理原地升级换代（The intermediate message (core) is not protocol-agnostic: switching protocols/models causes identity churn; cross-protoc | 中间消息(core)没有做到协议无关:切协议/切模型制造身份 churn,补齐跨协议映射 #3642 id re-key）后 dsh fork 子会话确定性卡死。
什么原因导致的（分层）：表层——gate 把「前缀失配」当致命错误拒掉整个请求；深层——这道门不提供独有保护：子会话的真正唤醒路由是 session-id 绑定（recordPluginSession→resolveConversation），字节级前缀校验只是唤起后的附加安检，其保护面（历史漂移）由每轮 resent history 的 fold reconcile 完整覆盖，却握有对子会话唯一入口的生杀权。另外拒绝原因在决策点被吞掉（诊断盲点，已由 [PR] fix: classify FORK_PREFIX_CONFLICT rejections instead of failing blind (#3740) #3743 分类诊断补齐）。
影响范围与严重程度：所有首请求相对继承前缀漂移的 plugin-mode fork 子会话（版本偏斜导致 id 重铸、host 改写 body、重放截断/重排等触发面）；受影响的子会话完全不可用（主会话不受影响，用户可新建会话绕行）→ p2。
怎么修复的：gate 从 fail-closed 降为 advisory——失配时照常转发（收养）+ 打一条带分类的 warn（id-drift / hash-drift-under-same-id / ref-broken / prefix-longer-than-incoming 等），后续轮由 reconcile 拉平继承 folds；门保持 one-shot（首请求后自然绕过）。失配时 publicForkPrefix 保持 false，side-lane 启发照常发言。代价：漂移子会话首请求未折叠出站（一次性 token 峰），正确性无损。
是否有回归问题：逐项审过——accept 路径不变（匹配仍走快速路径）；one-shot 语义不变；父会话隔离有测试钉住（parentRevision 不动）；标题生成等侧请求污染主会话状态:prepareAnthropic 缺 isTitleGen 守卫、快照无条件覆盖、survivedCount 每请求空转 #388 side-lane kernel-no-touch 契约保持——新增测试钉住「首请求本身是声明的 side call（title-gen 形态）时同样收养且走 passthrough 分流，stats.requests 保持 0、snapshot 不动」。新可达路径已分析：收养后 publicForkPrefix=false 使启发式 demotion 理论可达，但 demotion 要求「全 bili-tools、无 host tools」的 body 形状，真实主请求恒带 host tools → 实际不可达，最坏情形一轮 passthrough（仍会转发，下一轮正常）。顺带发现一个既有小问题（requests>0 后每请求仍重算 verdict）——非本 PR 引入，未动。无 config surface / 持久化格式 / wire shape / kernel 变更。
是否破坏缓存：不涉及。
是否改了设计方向：有一处明确变更——fork 前缀门语义 fail-closed → advisory，属「产品决策」类变更（§7.4 human-gated）。⚠️ PR 描述与 CHANGELOG 均引用「owner 在 This run failed with 409: "first child request does not match its inherited ordered prefix" | 本轮运行失败409 "first child request does not match its inherited ordered prefix" #3741 拍板」，但我查了平台 acp_delegate_wait reports "Failed" on a normal wait timeout while the delegate is still running #3740（全部楼层）、GitHub This run failed with 409: "first child request does not match its inherited ordered prefix" | 本轮运行失败409 "first child request does not match its inherited ordered prefix" #3741（全部评论）、PR [PR] fix: classify FORK_PREFIX_CONFLICT rejections instead of failing blind (#3740) #3743（全部评论）——所有评论均为 agent 所发，任何公开线程里都没有找到明确的 owner 批准记录。若你在别处拍过板，请在本线程链接/确认；否则请在此明确 sign-off 后再合。
是否引入了新的配置：不涉及。

审核中发现的问题与处置（均已直接修掉，3 个标注 commit 已推到 fix/fork-prefix-advisory，当前 head `d1da179`）

过期注释：src/agent/fork-adopt.ts 的 HASH PARITY CONTRACT 注释仍描述旧 409 行为（「any drift here poisons the child conversation permanently」）——与代码事实不符，已更新为 advisory 语义。
本 PR 引入的测试覆盖缺口：翻转掉的测试删掉了 [PR] fix: classify FORK_PREFIX_CONFLICT rejections instead of failing blind (#3740) #3743 分类器两个分支仅有的 pin（hash-drift-under-same-id、ref-broken——含「pruned ref 不得误标 hash-drift」的修正），新 warn 正则也不覆盖 ref-broken → 补了直接调用 publicForkInputCheck 的单测带负向断言把两分支钉住。
lane-guard 红（真实 CI 拦点）：handle.ts 的注释改动命中 lane 符号正则，但四个专用 side-lane 套件一个都没更新 → 在 tests/fork-side-request-lane.test.ts 加了真实覆盖用例（漂移首请求 + 声明 side call → 收养且 passthrough 分流），本地模拟 lane-guard 逻辑通过。

行为变更披露（旧 → 新）

旧：首请求前缀失配 → HTTP 409 {ok:false, code:'FORK_PREFIX_CONFLICT', detail:<分类原因>}，子会话永久卡死；新：照常转发（200）+ 一条 [fork-prefix] <sessionId>: inherited prefix mismatch — adopting anyway (<reason>; protocol=<protocol>) warn。有意变更，CHANGELOG 已披露。

验证状态

本地定向：typecheck 干净；tests/plugin-fork.test.ts 49/49（含新增 1）、tests/fork-side-request-lane.test.ts 2/2（含新增 1）、dsh-fork-adopt + pi-omp-fork-adopt 42/42。全量交远程 CI（d1da179a5 上运行中，出结果后跟进）。

判定：技术可合——方向正确（移除产生缺陷的机制而非掩盖症状）、回归清点干净、测试有牙。唯一拦点是第 7 问：PR 引用的「owner 决策」记录在所有公开线程中找不到，请确认或在此明确 sign-off；CI 转绿后人工合并即可。

小注：PR 描述写「src/server/handle.ts，净 -6 行」，-6 实为整个 PR 的净值（handle.ts 因注释块展开自身略增）。

ranxianglei · 2026-10-19T02:23:01Z

🤖 Powered by ework · qwen3.8-27b

(ai: vllm-qwen/qwen3.8-27b)

CI 跟进（上条回复承诺的）：给 PR 加了 ci:full 标签（与 #3743 同一机制——无此标签时 pull_request 事件的全量矩阵按设计跳过），全量矩阵已在 head d1da179 上跑完。

结果：全绿。

主 CI 工作流 27/27 job 通过：全部静态门（含 lane-guard，我补的 side-lane 用例解决了原始 head 上的那个红）+ 12 个 test leg（ubuntu/windows × node 22/24 × 3 shard）+ 4 个 static-gates leg；red-signal 哨兵按设计 skipped。
10 条 e2e lane 全部 success（real codex / fake codex / codex-persona / native pi / pi-codex-ws / dsh-plugin-lane / native-dsh / native-opencode / local-registry / windows codex overlay）。
中途一次红，已查明并消除：test (windows-latest, node 24, shard 3) 首跑失败——不是断言失败，是 tests/plugin-terminal-usage.test.ts 的 "HTTP Responses failed does not fabricate an input usage observation" 撞上 10s 测试超时（failureType=testTimeoutFailure；同族兄弟用例在该 runner 上跑了 3–5s，负载下越线）。与本 PR 无关（terminal-usage 子系统，fork 门改动碰不到它）：我在 PR head 本地定向跑该套件 9/9 绿。重跑后该 leg 转绿。
分支与 master 无文件重叠（master 期间又合了 [PR] fix: return valid JSON placeholder on re-request when compress tool params are malformed/truncated, breaking upstream 40 | fix: compress 工具参数畸形/截断时 re-request 回传合法 JSON 占位,断掉上游 400 死锁 (#3661) #3678/[PR] fix: three-state health probe — a busy proxy is no longer misjudged as dead (#3654) #3673/[PR] #2924 oversize 422: point dead-scope users at a host restart, not a futile retry #3595/[PR] fix(#2645): probe-and-remember prompt_cache_key — stamp by default, self-heal strict upstreams #3736 等，均不触碰本 PR 四个文件），干净可合。

最终状态：CI 全绿 + 本地定向验证全过 + 回归清点干净。唯一待办仍是上条第 7 问——PR 引用「owner 在 #3741 拍板」，但公开线程里找不到这条决策记录；请确认或在此明确 sign-off advisory 方向后即可人工合并（合并由你操作）。

github-actions · 2026-10-19T02:47:08Z

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npm install -g billion-context@0.0.588-master.a8853fe  # this exact build
npm install -g billion-context@master  # always the newest merged build

npm view billion-context@master prints the current version at any time.

ranxianglei changed the title ~~fix: fork prefix gate is advisory — adopt drifted fork children with a classified warn (#3741)~~ [PR] fix: fork prefix gate is advisory — adopt drifted fork children with a classified warn (#3741) Oct 19, 2026

awork added 3 commits October 19, 2026 09:42

ranxianglei added bug Something isn't working dsh opencode p2 pi scope/kernel ci:full Run the FULL CI matrix (all e2e lanes + 12-leg test matrix) on this PR labels Oct 19, 2026

ranxianglei mentioned this pull request Oct 19, 2026

[PR] Snapshot rendering: proxy lane outbound prefix rendered from server-side canonical history; existing sessions immune to | 快照渲染:proxy 车道出站前缀从服务端正史渲染,存量会话对内核升级免疫(#3756) #3759

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Merge branch 'master' into fix/fork-prefix-advisory

af61c62

ranxianglei merged commit a8853fe into master Oct 19, 2026
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ranxianglei mentioned this pull request Oct 19, 2026

0.1.200 → 0.1.201 upgrade (#3658 identity change) mass-unfolds persisted sessions incl. Anthropic lane; downgrade re-churns #3752

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github-actions Bot mentioned this pull request Oct 19, 2026

[PR] release v0.1.202 #3781

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tharanee-bit mentioned this pull request Oct 20, 2026

OpenAI wire: folded text that gains an opaque content part can lose that part #4042

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[PR] fix: fork prefix gate is advisory — adopt drifted fork children with a classified warn (#3741) - #3757

[PR] fix: fork prefix gate is advisory — adopt drifted fork children with a classified warn (#3741)#3757
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ranxianglei commented Oct 19, 2026

为什么拆这扇门

改动(src/server/handle.ts,净 -6 行)

测试(tests/plugin-fork.test.ts 翻转,48/48 绿)

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ranxianglei commented Oct 19, 2026

审核结论（八问）

审核中发现的问题与处置（均已直接修掉，3 个标注 commit 已推到 fix/fork-prefix-advisory，当前 head d1da179）

行为变更披露（旧 → 新）

验证状态

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📦 Merged Build Published

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审核中发现的问题与处置（均已直接修掉，3 个标注 commit 已推到 fix/fork-prefix-advisory，当前 head `d1da179`）