docs(settings): third-review contracts across READMEs, catalogs, and the write-path integrity note

The seam README states the JSON-shaped write boundary, watch-disposer
quiescence, async listener containment, and the drained teardown; the
provider README rewrites Behavior around the operation chain,
read-modify-write, writer lock, ready reconcile, and leaf-level YAML
diffs, and updates Known Limitations to the residual guarantees.
A new Agent Note records the round's decisions and supersedes the
original note's deferred-lockfile alternative (cross-linked in place).
Chinese counterparts updated pair-by-pair (three briefed minimal
updates, one whole-document translation); type-equiv, config, cordis,
and module-graph catalogs re-recorded.
This commit is contained in:
Yichen Jiang
2026-07-30 14:09:04 +08:00
parent 85a3a158dd
commit 3b1b912518
21 changed files with 152 additions and 45 deletions

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# side as of the last confirmed-consistent state. Both languages carry equal authority;
# after editing either side, bring the other along and re-record with:
# pnpm run verify-translation-pairing --write .agents/notes/implemented/architecture/2026-07-28-user-settings-seam.md
2026-07-28-user-settings-seam.md: f0f45d77c8f98fc15625b1a1bf116ec10b965676
2026-07-28-user-settings-seam.zh.md: eb562099b1ff0b5b0a019e9956d6e36e71857236
2026-07-28-user-settings-seam.md: bf93f95168b1b6d0dec5a9fc2c9aac5531f0564a
2026-07-28-user-settings-seam.zh.md: 8cd4dfcbb2facdd590b2c24d453ad79e9badda4d

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@@ -14,7 +14,7 @@ User-editable configuration had no owner: `dsh web` read a cwd-anchored profile
**Two planes with a litmus test.** `cordis.yml` (+ Include patches) stays the composition plane: which plugins exist, wiring, deployment config, owned by the orchestrator and upgraded with the product. A settings namespace carries only the user-editable subset; the test is "should the personal config page edit it?" Values live in both planes without ambiguity because layering is the contract: schema defaults, then the registrant's composition `base` (its entry-config subset), then the user document section.
**Three-package seam mirroring `session-persistence/`.** `dsh-settings` owns the abstract `Settings` service: namespace registry, layered resolution, schema validation, per-namespace deep-equal change detection, and the `settings/updated` commit event. Providers implement only `writable`/`load()`/`persist(ns, section)` and push externally observed documents through the protected `publish(doc)` — so hot-update semantics are identical across providers, and a network configuration-center backend (nacos-style, possibly read-only) is a sibling package away. `dsh-settings-local` is the file provider: YAML/JSON under `resolveSpec` (explicit defaulting to `<DSH_HOME>/settings.yaml`), chokidar watch, atomic `0600` tmp+rename writes, comment-preserving YAML patching of exactly one namespace key, and content-equality self-write suppression.
**Three-package seam mirroring `session-persistence/`.** `dsh-settings` owns the abstract `Settings` service: namespace registry, layered resolution, schema validation, per-namespace deep-equal change detection, and the `settings/updated` commit event. Providers implement only `writable`/`load()`/`persist(ns, section)` and push externally observed documents through the protected `publish(doc)` — so hot-update semantics are identical across providers, and a network configuration-center backend (nacos-style, possibly read-only) is a sibling package away. `dsh-settings-local` is the file provider: YAML/JSON under `resolveSpec` (explicit defaulting to `<DSH_HOME>/settings.yaml`), chokidar watch, read-modify-write persists under a cross-process writer lock with atomic `0600` tmp+rename commits, leaf-level diff patching of the written namespace (comments survive untouched nodes), and content-equality self-write suppression ([write-path integrity note](2026-07-30-settings-write-path-integrity.md)).
**Registrations are caller-fiber effects.** `register()` runs through the service proxy, so `this.ctx` is the registrant's context and the registration rides `ctx.effect`: disposing the registrant removes the namespace and its watchers (proven by the HMR disposal test), while the user's section keeps living in storage for the next owner.
@@ -28,7 +28,7 @@ User-editable configuration had no owner: `dsh web` read a cwd-anchored profile
- **Loader-reactive `fiber.update` as the propagation channel**: constructor-time reads observe nothing; the seam's explicit `watch()` makes hot-update a consumer contract instead of framework magic.
- **A domain-aware settings service** (getters per product area): the coupling objection from design review stands; the service stores, validates, and publishes — domain meaning stays with the registrant that owns the schema.
- **Multi-layer precedence now** (system/managed/project tiers à la Codex/Claude Code): deferred until a real second layer exists; the resolve step is the single place layering would extend.
- **A cross-process lockfile now** (Pi's proper-lockfile): atomic replace plus watcher convergence (last write wins) is documented behavior until real contention shows up.
- **A cross-process lockfile now** (Pi's proper-lockfile): initially deferred as "atomic replace plus watcher convergence until real contention shows up" — review showed convergence loses unobserved sibling namespaces, so the deferral is superseded by the [write-path integrity note](2026-07-30-settings-write-path-integrity.md)'s hand-rolled writer lock.
## Consequences

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**两个面,一条判定。**`cordis.yml`(+ Include patches)仍是组合面:有哪些插件、接线、部署配置,归 orchestrator 所有并随产品升级。settings namespace 只承载用户可编辑子集;判定是"个人配置页应该能改它吗?"值可同时存在于两个面而不歧义,因为分层就是契约:schema 默认值,然后注册方的组合 `base`(其 entry 配置子集),最后用户文档分节。
**镜像 `session-persistence/` 的三包 seam。**`dsh-settings` 拥有抽象 `Settings` 服务:namespace 注册表、分层解析、schema 校验、按 namespace 深相等变更检测,以及 `settings/updated` 提交事件。provider 只实现 `writable`/`load()`/`persist(ns, section)`,并通过受保护的 `publish(doc)` 推入外部观察到的文档——因此热更新语义对所有 provider 一致,网络配置中心后端(nacos 类,可能只读)只是一个平级包的距离。`dsh-settings-local` 是文件 provider:`resolveSpec` 显式默认到 `<DSH_HOME>/settings.yaml` 的 YAML/JSON、chokidar 监听、`0600` tmp+rename 原子写、只修补目标 namespace 键的保注释 YAML 写回、按内容相等抑制自写。
**镜像 `session-persistence/` 的三包 seam。**`dsh-settings` 拥有抽象 `Settings` 服务:namespace 注册表、分层解析、schema 校验、按 namespace 深相等变更检测,以及 `settings/updated` 提交事件。provider 只实现 `writable`/`load()`/`persist(ns, section)`,并通过受保护的 `publish(doc)` 推入外部观察到的文档——因此热更新语义对所有 provider 一致,网络配置中心后端(nacos 类,可能只读)只是一个平级包的距离。`dsh-settings-local` 是文件 provider:`resolveSpec` 显式默认到 `<DSH_HOME>/settings.yaml` 的 YAML/JSON、chokidar 监听、跨进程写锁下以 `0600` tmp+rename 原子提交的读-改-写 persist、对被写 namespace 的叶子级 diff 修补(未触碰节点的注释得以保留)、按内容相等抑制自写([write-path integrity note](2026-07-30-settings-write-path-integrity.md))。
**注册是调用方 fiber 上的 effect。**`register()` 经服务代理调用,`this.ctx` 即注册方 context,注册挂在 `ctx.effect` 上:dispose 注册方即移除 namespace 及其观察者(HMR disposal 测试证明),而用户的分节继续留在存储中等待下一任 owner。
@@ -28,7 +28,7 @@ Status: implemented
- **以 Loader reactive `fiber.update` 为传导通道**:构造期读取毫无感知;seam 的显式 `watch()` 把热更新变成消费者契约而非框架魔法。
- **领域化的 settings 服务**(按产品域的 getter):设计评审中的耦合反对成立;服务只做存储、校验、发布——领域含义留给拥有 schema 的注册方。
- **现在就做多层优先级**(Codex/Claude Code 式 system/managed/project 层级):延后到真实第二层出现;resolve 步骤是分层未来唯一的扩展点。
- **现在就上跨进程锁**(Pi 的 proper-lockfile):原子替换加 watcher 收敛(后写胜出)是已记录的行为,真实冲突出现再说。
- **现在就上跨进程锁**(Pi 的 proper-lockfile):最初以"原子替换加 watcher 收敛,真实冲突出现再说"为由延后——评审发现收敛会丢失未观察到的同级 namespace,因此该延后已被 [write-path integrity note](2026-07-30-settings-write-path-integrity.md) 的手写写锁取代。
## 后果

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# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
# side as of the last confirmed-consistent state. Both languages carry equal authority;
# after editing either side, bring the other along and re-record with:
# pnpm run verify-translation-pairing --write .agents/notes/implemented/architecture/2026-07-30-settings-write-path-integrity.md
2026-07-30-settings-write-path-integrity.md: 07bd095162879c8e7866846cf562f6a13307e5fc
2026-07-30-settings-write-path-integrity.zh.md: 5d02177073d482b61750d7bdfbbd0866bc227a6a

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# Agent Note: settings write-path integrity and observer lifecycle
Status: implemented
English | [中文](2026-07-30-settings-write-path-integrity.zh.md)
> Scope: the third review round over `packages/settings/` — write-path data integrity in `dsh-settings-local` (operation chain, read-modify-write, cross-process writer lock, diff-shaped YAML edits) and observer lifecycle in `dsh-settings` (watch disposal, async listener containment, the JSON-shape write boundary). This note reverses one deferral recorded in the [user-settings seam note](2026-07-28-user-settings-seam.md): the cross-process lockfile now ships.
## Problem
Review found the provider's write path could destroy state it never observed, and the seam's observer lifecycle leaked past disposal. Concretely: watcher reloads and document writes ran on two independent promise chains while every write rendered the whole next document from the cached text, so an external edit still inside the debounce window was overwritten — and the follow-up reload no-oped because the post-rename content matched the cache, erasing the edit without a trace. The initial `load()` raced the watcher's own setup, leaving a startup window whose changes never fire an event. Two processes sharing a harness home rendered from independent caches, last writer winning whole namespaces. On the seam side, a `watch()` disposer only removed the observer from its set — an invocation already chained onto the watcher tail still ran after disposal, and nothing drained started invocations at service dispose; the `settings/updated` manual fan-out caught only synchronous throws, so an async listener's rejection escaped as an unhandled rejection; and `structuredClone` admitted Dates, Maps, BigInts, and cycles that YAML/JSON storage silently distorts on the reload round-trip (a Date lands as a timestamp string, a BigInt as a plain number). YAML writes replaced the whole namespace node, deleting every comment inside the section a comment-preserving provider had promised to keep.
## Decision
**One operation chain, and every write is a read-modify-write.** Watcher refreshes and persists from every namespace queue share a single settled chain, and `persistSection` begins by reconciling the on-disk text into the seam — publishing any unobserved difference first — before rendering against that fresh text. A write can no longer resurrect a stale document, and an on-disk document that turned invalid fails the write loud rather than being overwritten (the reload path keeps its warn-and-keep-last-good policy; the shared `reconcileFromDisk` throws and each caller picks its policy). The watcher's `ready` signal queues one extra reconcile, closing the startup gap between the initial load and the watcher becoming active.
**Writes hold a `wx`-created `<file>.lock` sibling.** The read-render-rename cycle runs under a cross-process writer lock with exponential backoff, a 2 s acquisition deadline, and stale takeover after 5 s (a crashed holder, broken with a warning). Readers never lock — the rename commit is atomic — so contention is writer-only and resolves in milliseconds. The lock constants are protocol invariants, not config: a holder rewrites one small document, so the deadline and stale age derive from that bound, not from deployment taste.
**Observer disposal is quiescent.** Watchers carry an `active` flag checked when a queued invocation would start, so a disposer that ran while the invocation waited prevents the start entirely; started invocations register in a service-level `pendingTails` set that the dispose drain awaits beside the write queues. The `settings/updated` fan-out contains a returned thenable's rejection through the same listener diagnostic as a sync throw, and the event contract now states that the `INVARIANT` rethrow serves synchronous listeners only — invariant companions must stay sync, which the shipped companion already is.
**The write boundary admits JSON data only.** The call-time snapshot is a single `cloneJsonShaped` walk that detaches the patch and rejects any non-JSON value — Date, Map, BigInt, non-finite number, function, symbol, class instance, `undefined` array entry, circular reference — with its `$`-rooted path before anything persists. Object entries that are explicitly `undefined` still skip (the sparse-patch contract), now enforced at the boundary instead of inside `mergeLayers`.
**YAML edits are leaf-level diffs.** `renderYaml` diffs the stored section against the next one and applies only `setIn` for changed values and `deleteIn` for removed keys, recursing through maps. Comments, anchors, and formatting survive on every untouched node and on the key node of every changed pair; arrays and other non-map values replace wholesale when unequal (`deepEqualJson` is the shared predicate), taking comments inside them along.
## Alternatives considered
- **`proper-lockfile` instead of a hand-rolled lock** — the dependency-over-hand-rolling policy was weighed: the library is barely maintained, its stale/retry policy is broader than this one-file protocol needs, and the shipped lock is ~40 lines with deterministic tests (including injected `EEXIST`/`stat` races). The policy favors dependencies that delete owned code; this one would replace 40 explained lines with an opaque peer.
- **Revision/CAS instead of a lock** — rename cannot express compare-and-swap, so a CAS needs a version sidecar or content re-hash and a retry loop in every writer; the lock achieves the same serialization with one primitive and keeps readers free.
- **Merging external edits into the in-flight write's own section** — the seam merges patches over the state visible at call time, so a same-namespace external edit racing a write still resolves last-write-wins; folding it in would need three-way merge semantics no consumer has asked for. The write publishes the external state first, so the loser is at least observed before being superseded.
- **Declaring async `settings/updated` listeners unsupported** — the typed signature is `void` and lint flags misused promises, but an unlinted JS plugin can still register an async listener; a contract note cannot un-throw an unhandled rejection, so containment is the only defense that holds at runtime.
- **Keeping `structuredClone` and validating in the provider** — the seam is the durable boundary's owner (every provider stores JSON-shaped documents), and rejecting at call time gives the caller the offending path; a provider-side check would reject after merge, blaming the merged section instead of the caller's value.
## Consequences
`update()` gained a documented failure mode (lock deadline, invalid on-disk document) and the rejection messages carry `$`-rooted paths. Remaining, documented in the provider README: same-namespace concurrent edits stay last-write-wins (no per-value merge or revision check), a watcher event the OS never delivers leaves the cache stale until the next signal or write, and comments inside replaced arrays or attached inline to changed scalar values go with the value they described. The [user-settings seam note](2026-07-28-user-settings-seam.md)'s deferred-lockfile alternative is superseded by this note. The same defect classes exist in `dsh-credentials-local` (two chains over one `.env`, cached whole-file write-back, post-persist emit) and in the `llm/adapters-updated` fan-out on the stacked branches; those fixes belong to the PRs that introduce the packages and follow this template on merge-up.

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# Agent Note: settings 写路径完整性与观察者生命周期
Status: implemented
[English](2026-07-30-settings-write-path-integrity.md) | 中文
> 范围:对 `packages/settings/` 的第三轮评审——`dsh-settings-local` 的写路径数据完整性(操作链、读-改-写、跨进程写锁、diff 形态的 YAML 编辑)与 `dsh-settings` 的观察者生命周期(watch 的 dispose(资源释放)、异步监听器收容、JSON 形态写入边界)。本 note 推翻了[用户设置 seam note](2026-07-28-user-settings-seam.md)所记录的一项延后决定:跨进程锁文件现已交付。
## 问题
评审发现,提供方的写路径可能销毁它从未观察到的状态,而 seam 的观察者生命周期会泄漏到 dispose 之后。具体而言:watcher 重载与文档写入跑在两条相互独立的 promise 链上,而每次写入都从缓存文本渲染出完整的下一份文档,于是仍处于防抖窗口内的外部编辑会被覆盖——随后的重载又因 rename 后的内容与缓存一致而成为空操作,这次编辑就被无痕抹去。初始 `load()` 与 watcher 自身的建立过程存在竞态,留下一个启动窗口:落在这个窗口内的变更永远不会触发事件。共享同一 harness home 的两个进程各自从独立的缓存渲染,后写者以整个 namespace 为单位胜出。
在 seam 一侧,`watch()` 的释放器只把观察者从集合中移除——已经接到 watcher 链尾的调用在 dispose 之后照常运行,服务 dispose 时也没有任何环节排空已启动的调用;`settings/updated` 的手动扇出只捕获同步抛错,异步监听器的 rejection 会以 unhandled rejection 的形式逃逸;`structuredClone` 则放行 Date、Map、BigInt 与循环引用,而 YAML/JSON 存储会在重载往返中悄悄扭曲这些值(Date 会变成时间戳字符串,BigInt 会变成普通数字)。
YAML 写入则整体替换 namespace 节点,把分节内的每条注释都删掉——而这个保注释的提供方承诺过要保住它们。
## 决策
**单一操作链,且每次写入都是读-改-写。**watcher 的刷新与来自各 namespace 队列的持久化共享同一条结算链;`persistSection` 会先把磁盘上的文本对账进 seam——任何未被观察到的差异都先发布出去——然后才对照这份新鲜文本渲染。写入不再可能复活一份陈旧文档;磁盘上已变非法的文档会让写入响亮失败,而不是被覆盖(重载路径保持其“告警并保留最后可用值”策略;共享的 `reconcileFromDisk` 抛错,各调用方自选策略)。watcher 的 `ready` 信号会额外排入一次对账,弥合初始加载与 watcher 生效之间的启动缺口。
**写入持有以 `wx` 创建的同目录 `<file>.lock`。**读-渲染-rename 循环在一把跨进程写锁下运行:指数退避、2 s 获取截止时间、5 s 后陈旧接管(持有者已崩溃;打破旧锁时给出告警)。读方从不加锁——rename 提交是原子的——因此竞争只发生在写方之间,毫秒级即可化解。锁的各项常量是协议不变式,不是配置:持有者只是重写一份小文档,截止时间与陈旧时限都从这一上界推得,而非出自部署偏好。
**观察者 dispose 达到完全停稳。**watcher 携带一个 `active` 标志,排队的调用即将启动时先检查它,因此在调用等待期间已经运行过的释放器能让这次启动彻底不发生;已启动的调用会登记进服务级的 `pendingTails` 集合,dispose 排空除了等待各写队列,还会等待该集合。`settings/updated` 扇出会把监听器返回的 thenable 的 rejection 收容进与同步抛错相同的监听器诊断;事件契约现已写明 `INVARIANT` 重抛只服务同步监听器——不变式配套插件必须保持同步,而已交付的那个配套插件本就是同步的。
**写入边界只放行 JSON 数据。**调用时刻的快照就是一次 `cloneJsonShaped` 遍历:它把 patch 从调用方分离出来,并在任何内容持久化之前拒绝一切非 JSON 值——Date、Map、BigInt、非有限数值、函数、symbol、类实例、值为 `undefined` 的数组元素、循环引用——拒绝时附带该值以 `$` 为根的路径。显式为 `undefined` 的对象条目仍会跳过(稀疏 patch 契约),这一契约如今在边界处强制执行,而不再放在 `mergeLayers` 内部。
**YAML 编辑是叶子级 diff。**`renderYaml` 对比已存储分节与下一份分节,只对变化的值应用 `setIn`、对移除的键应用 `deleteIn`,并沿 map 递归。注释、锚点与格式在每个未触碰节点上、以及每个被改键值对的键节点上全部保留;数组等非 map 值在不相等时整体替换(`deepEqualJson` 是共享的判定谓词),其内部注释随之一并被带走。
## 曾考虑的替代方案
- **用 `proper-lockfile` 取代手写锁**——按“依赖优先于手写”政策做过权衡:该库几乎无人维护,其陈旧/重试策略比这个单文件协议所需的更宽泛,而已交付的锁约 40 行并带确定性测试(含注入的 `EEXIST`/`stat` 竞态)。该政策偏向能删除自有代码的依赖;这个依赖只会把 40 行带解释的代码换成一个不透明的等价物。
- **用修订号/CAS 取代锁**——rename 表达不了 compare-and-swap,因此 CAS 需要一个版本伴随文件或内容重哈希,外加每个写方里的一个重试循环;锁用一个原语实现同样的串行化,还让读方完全免锁。
- **把外部编辑合并进正在进行的写入自身的分节**——seam 是在调用时刻可见的状态之上合并 patch 的,因此与写入竞态的同 namespace 外部编辑仍按后写胜出解决;要把外部编辑并进来,需要三方合并语义,而没有任何消费方提出过这种需求。写入会先发布外部状态,落败一方至少在被取代之前被观察到。
- **宣布不支持异步 `settings/updated` 监听器**——类型签名是 `void`,lint 也会标记误用的 promise,但未经 lint 的 JS 插件仍能注册异步监听器;契约里的一句说明无法收回已经抛出的 unhandled rejection,收容是唯一在运行时守得住的防线。
- **保留 `structuredClone`、在提供方里做校验**——seam 才是持久化边界的所有者(每个提供方存储的都是 JSON 形态文档),而且在调用时刻拒绝能把违规值的路径给到调用方;提供方侧的检查要到合并之后才拒绝,归咎的是合并后的分节,而不是调用方传入的值。
## 后果
`update()` 有了成文的失败模式(锁截止时间到期、磁盘文档非法),rejection 消息携带以 `$` 为根的路径。仍然存在、且已记录在提供方 README 中的有:同 namespace 并发编辑仍是后写胜出(没有逐值合并,也没有修订号检查);OS 从未投递的 watcher 事件会让缓存保持陈旧,直到下一个信号或下一次写入;被替换数组内部的注释、以及行内附着在被改标量值上的注释,会随其描述的值一起消失。
[用户设置 seam note](2026-07-28-user-settings-seam.md)里“延后锁文件”那条替代方案已被本 note 取代。同类缺陷还存在于 `dsh-credentials-local`(两条链共用一个 `.env`、按缓存整文件写回、持久化之后才发事件)与堆叠分支上的 `llm/adapters-updated` 扇出;这些修复归引入相应包(package)的那些 PR(Pull Request)所有,向上合并时按本模板处理。