From 54c893d7af3c6a1e8c54a9d892d6a9533e0920b3 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Tue, 28 Jul 2026 11:07:23 +0800
Subject: [PATCH] =?UTF-8?q?docs:=20RFC=20=E2=80=94=20storage=20root=20plac?=
 =?UTF-8?q?ement=20and=20derived-medium=20recovery?=
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The projection cache surfaced two substrate gaps, both properties of the
domain-KV stack it landed on. (1) The json backend's root is relative and
joined per-open against process.cwd(): sessions are patched global
(~/.dsh/sessions) but workspace.json/session_projcache.json land under
<launch dir>/.storages, splitting derived media from their source of
truth. Proposal: patch storage-json.root to ~/.dsh/storages beside the
session root (profile key storageRoot, mirroring persistenceRoot) and
resolve-once at backend construction, adopting the JSONL backend's
recorded rationale. (2) A damaged cache medium (truncated / version-bumped
/ schema-drifted) bricks fail-loud boot even though its content is fully
rebuildable from session logs. Proposal: DomainSpec grows
recovery: 'reject' | 'reset'; the facility, on exactly the damage-class
errors, destroys a declared-reset medium once and reopens empty —
workspace stays authoritative and loud. Bilingual pair recorded.
---
 ...root-and-derived-medium-recovery.i18n.yaml |  6 ++
 ...torage-root-and-derived-medium-recovery.md | 57 +++++++++++++++++++
 ...age-root-and-derived-medium-recovery.zh.md | 57 +++++++++++++++++++
 3 files changed, 120 insertions(+)
 create mode 100644 .agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml
 create mode 100644 .agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
 create mode 100644 .agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md

diff --git a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml
new file mode 100644
index 0000000000..af41b392bd
--- /dev/null
+++ b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml
@@ -0,0 +1,6 @@
+# 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/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
+2026-07-28-storage-root-and-derived-medium-recovery.md: 06fa98b10dc5ac3164d8905e7005a42d9e99ae92
+2026-07-28-storage-root-and-derived-medium-recovery.zh.md: b7bd18ffdbfaf412d9a91940cf1770e273f5b847
diff --git a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
new file mode 100644
index 0000000000..06fa98b10d
--- /dev/null
+++ b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
@@ -0,0 +1,57 @@
+# Agent Note: Storage root placement and derived-medium recovery
+
+Status: proposed
+
+English | [中文](2026-07-28-storage-root-and-derived-medium-recovery.zh.md)
+
+## Problem
+
+The persisted projection cache ([RFC](2026-07-27-session-projection-and-command-log.md), shipped as `dsh-session-projection-cache`) surfaced two gaps in the storage substrate it landed on. Both are properties of the domain-KV stack ([design](2026-07-24-domain-kv-storage-and-workspace.md)), not of the cache itself, and both bite the cache first because it is the first *derived* medium on that stack.
+
+**Where the files actually live.** The shipped composition gives the json backend a relative root — `root: './.storages'` (apps/cli/cordis.yml) — and `AppCLIEntry.composePatches` patches only the session store's root to the global harness home (`$DSH_HOME/sessions`, default `~/.dsh/sessions`, profile-overridable via `persistenceRoot`); no equivalent patch or profile key exists for `storage-json`. `JsonStorageBackend` never resolves its root either — each unit open joins the still-relative path against whatever `process.cwd()` is at that moment (packages/storage/storage-json/src/index.ts) — the exact hazard the JSONL session backend resolves-once to prevent ("later process.cwd() changes cannot split one backend across roots", packages/session-persistence/session-persistence-jsonl/src/index.ts). Net effect: session logs are global across launch directories, but `workspace.json` and `session_projcache.json` land under `<launch dir>/.storages/`. Two launches from different directories share their sessions yet see different workspace registries and different projection caches — and the cache exists precisely to serve the cross-session cold listing, which now misses for every session last cached under another launch directory.
+
+**How recovery works today.** Inside a healthy medium the cache is fully self-healing by design: a `stateVersion`-mismatched row is discarded and refolded, a log shrunk below a row's watermark is detected by the anchored restore floor and answered with one full re-read, and every background write is fail-soft. But at the *medium* level there is no recovery at all: a truncated, hand-edited, or version-bumped `session_projcache.json` fails `openJsonUnit` with `malformed-medium`/`version-mismatch` (packages/storage/storage-json/src/format.ts), a schema-drifted record fails domain open with `invalid-record` (packages/storage/storage-domain/src/index.ts), the rejection propagates through `SessionProjectionCache[Service.init]`, and under the CLI's fail-loud boot the assembly refuses to start. A file whose entire content is rebuildable from session logs can brick boot. This contradicts the cache package's own stated stance ("a stale or unreadable cache costs a longer tail replay, never a wrong value") and the cache domain spec's JSDoc ("version bumps discard the whole medium"), which today describes an aspiration, not the implementation. The same fail-loud path is *correct* for `workspace.json` — workspace records are authoritative, not derivable — so the missing concept is a per-domain declaration of authority, not a global behavior change.
+
+## Proposal
+
+Two independent changes, one per gap.
+
+### One global storage root, resolved once
+
+- `AppCLIEntry.composePatches` Source 0 additionally patches `storage-json.root` to `join(resolveDshHome(), 'storages')` — `~/.dsh/storages` by default, beside `~/.dsh/sessions` — and `PROFILE_MAPPINGS` gains `storageRoot` → (`storage-json`, `root`), mirroring `persistenceRoot` exactly. The yml keeps `./.storages` as the raw-composition engineering default (tests and bare Loader boots are unaffected), same layering as the session root today.
+- `JsonStorageBackend` resolves its configured root once at construction (`resolve(config.root)`), adopting the JSONL backend's recorded rationale verbatim: a later `process.cwd()` change must not split one backend across roots. The SQLite storage backend already resolves its path.
+- Pre-release stance applies: no migration shim. A deployment that cached under `<cwd>/.storages` re-derives everything (workspace re-bootstraps from the header index; the projection cache refolds lazily) or moves the two json files by hand once.
+
+### Declared derived media: reset instead of reject
+
+- `DomainSpec` gains `recovery?: 'reject' | 'reset'` (default `'reject'`). The spec object is already the single source of a domain's identity and layout; whether its medium is authoritative or derived is the same kind of fact and lives in the same place. `session_projcache` declares `'reset'`; `workspace` stays on the default.
+- `KvFacet` gains one primitive: `destroy(descriptor): Promise<void>` — remove the unit's medium entirely (json: delete the file; sqlite: drop the unit's tables). Like `open`, it is a backend storage primitive, not policy.
+- `DomainFacility.open`, when a spec declares `'reset'` and the open fails with exactly a damage-class error — `StorageError('version-mismatch' | 'malformed-medium')` or `DomainError('invalid-record')` — logs one warning naming the domain and the discarded medium, calls `destroy`, and opens again empty. Every other failure (`backend-not-found`, `facet-unsupported`, `already-open`, I/O errors) stays loud regardless of the declaration: misconfiguration and environmental faults are not medium damage. The retry is single-shot — a second failure propagates, so a persistently failing medium cannot loop.
+- With this in place the cache domain spec's version field gains its intended meaning: bumping `version` (or letting zod reject drifted rows) genuinely discards the whole medium and the cache rebuilds through its normal write points and cold reads — the recovery ladder's outermost rung, matching the row-level rungs already shipped.
+
+## Alternatives considered
+
+**Keep per-launch-directory `.storages` (status quo)** — rejected: sessions are global, so every derived-from-sessions medium splits against its own source of truth; the cache's motivating scenario (one listing over all sessions) structurally misses rows, and the workspace registry indexes sessions it cannot see from another launch directory.
+
+**Patch only the projection cache's route to a global root, leave `workspace.json` per-cwd** — rejected: the workspace registry has the identical global-vs-cwd mismatch, and the user decision that shaped the cache placed it deliberately beside `workspace.json` — one hub root keeps the media co-located and the mental model single.
+
+**Cache-plugin-local recovery (catch damage errors in `SessionProjectionCache[Service.init]`, delete the file, reopen)** — rejected: the plugin cannot name the medium path without reaching around the backend abstraction, and every future derived domain would re-implement the same catch; the facility is the one place that already classifies open failures.
+
+**Fall back to an ephemeral in-memory domain on damage** — rejected: it silently degrades to memory-only for the life of the process and the damaged file never heals; the next boot fails the same way.
+
+**Rename the damaged medium aside (`<unit>.json.corrupt-<ts>`) instead of deleting** — not chosen: a derived medium's damaged bytes have no recovery value (the logs are the source of truth) and the litter accumulates unbounded; delete is the honest operation. Rename-aside remains the right choice if a future *authoritative* domain ever wants reset semantics — which is exactly why `recovery` is per-spec.
+
+**A blanket auto-reset for every domain (no spec field)** — rejected outright: `workspace.json` is authoritative user data; silently resetting it on a version bump would destroy workspaces. Authority is a property of the domain and must be declared by its owner.
+
+## Acceptance criteria
+
+- `dsh` launched from any directory reads and writes the same `$DSH_HOME/storages/*.json` (default `~/.dsh/storages`); the profile key `storageRoot` overrides it; a raw Loader boot of the yml still lands in `./.storages` relative to the boot cwd, resolved once at backend construction.
+- With a truncated, version-bumped, or schema-drifted `session_projcache.json`, the assembly boots clean: one warning names the discarded medium, the file is gone, the cache rebuilds through normal operation, and the cold listing column reappears as sessions are re-checkpointed.
+- The same damage to `workspace.json` still fails boot loudly.
+- Facility tests cover: each damage class resets a `'reset'` domain exactly once; non-damage failures stay loud on a `'reset'` domain; a `'reject'` domain propagates every failure; `destroy` removes the medium on both shipped backends.
+
+## Risks
+
+- **Auto-delete on a misclassified error destroys a healthy file.** Mitigated by the closed damage-class list: reset fires only on the three deterministic parse-time codes; ENOENT is already "empty unit", and every I/O error (EACCES, EIO) propagates loudly. The single-shot retry bounds the blast radius to one delete per open.
+- **Root relocation changes where existing checkouts look.** Accepted under the pre-release stance (backends reject old formats, no external consumers); the note above records the one-time manual move for anyone who cares about a per-cwd `workspace.json`'s content.
+- **`destroy` is a new destructive primitive on the storage seam.** Its only caller is the facility's declared-reset path; the backend contract documents it as facility-owned, and nothing model-facing or user-facing can reach it.
diff --git a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md
new file mode 100644
index 0000000000..b7bd18ffdb
--- /dev/null
+++ b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md
@@ -0,0 +1,57 @@
+# Agent Note：存储根目录落点与派生介质恢复
+
+Status: proposed
+
+[English](2026-07-28-storage-root-and-derived-medium-recovery.md) | 中文
+
+## Problem
+
+持久投影缓存（[RFC](2026-07-27-session-projection-and-command-log.md)，已作为 `dsh-session-projection-cache` 落地）暴露了它所依托的存储基座的两个缺口。二者都是 domain-KV 栈（[设计](2026-07-24-domain-kv-storage-and-workspace.md)）的属性而非缓存自身的问题，且都首先咬到缓存——因为它是这条栈上第一个*派生*介质。
+
+**文件到底存在哪。** 出厂组合给 json 后端的是相对根目录——`root: './.storages'`（apps/cli/cordis.yml）——而 `AppCLIEntry.composePatches` 只把会话存储的根 patch 到全局 harness home（`$DSH_HOME/sessions`，默认 `~/.dsh/sessions`，可经 profile 键 `persistenceRoot` 覆盖）；`storage-json` 没有对应的 patch 也没有 profile 键。`JsonStorageBackend` 自己也从不 resolve 根——每次打开 unit 都把仍然相对的路径 join 到当时的 `process.cwd()` 上（packages/storage/storage-json/src/index.ts）——这正是 JSONL 会话后端用「构造时 resolve 一次」防住的那个隐患（"later process.cwd() changes cannot split one backend across roots"，packages/session-persistence/session-persistence-jsonl/src/index.ts）。净效果：会话日志跨启动目录全局共享，但 `workspace.json` 和 `session_projcache.json` 落在 `<启动目录>/.storages/` 下。从两个不同目录启动，会话相同，工作区注册表和投影缓存却各是一份——而缓存存在的意义恰恰是跨会话冷列表，如今凡是上次在别的启动目录下缓存过的会话全部 miss。
+
+**现在是怎么恢复的。** 在健康介质内部，缓存按设计完全自愈：`stateVersion` 不匹配的行被丢弃重折，日志缩短到行水位以下由带锚的 restore floor 检出并以一次全量重读回答，每次后台写都是 fail-soft。但在*介质*层面完全没有恢复：被截断、被手改或版本被 bump 的 `session_projcache.json` 会让 `openJsonUnit` 以 `malformed-medium`/`version-mismatch` 失败（packages/storage/storage-json/src/format.ts），schema 漂移的记录让域 open 以 `invalid-record` 失败（packages/storage/storage-domain/src/index.ts），拒绝一路穿过 `SessionProjectionCache[Service.init]`，在 CLI 的 fail-loud 启动下整个组装拒绝启动。一个内容完全可从会话日志重建的文件能把启动搞死。这与缓存包自己声明的立场（"a stale or unreadable cache costs a longer tail replay, never a wrong value"）和缓存域 spec 的 JSDoc（"version bumps discard the whole medium"）相矛盾——后者今天描述的是愿望而非实现。同一条 fail-loud 路径对 `workspace.json` 却是*正确*的——工作区记录是权威数据，不可派生——所以缺的概念是按域声明权威性，而不是全局改行为。
+
+## Proposal
+
+两个独立改动，一个缺口一个。
+
+### 全局唯一存储根，构造时 resolve 一次
+
+- `AppCLIEntry.composePatches` 的 Source 0 追加把 `storage-json.root` patch 到 `join(resolveDshHome(), 'storages')`——默认 `~/.dsh/storages`，与 `~/.dsh/sessions` 并肩——并且 `PROFILE_MAPPINGS` 增加 `storageRoot` →（`storage-json`，`root`），与 `persistenceRoot` 完全镜像。yml 保留 `./.storages` 作为裸组合的工程默认（测试和裸 Loader 启动不受影响），分层方式与今天的会话根相同。
+- `JsonStorageBackend` 在构造时对配置根 `resolve` 一次，原样采纳 JSONL 后端已记录的理由：后续 `process.cwd()` 变化不得把一个后端劈到多个根下。SQLite 存储后端已经 resolve 其路径。
+- 适用 pre-release 立场：不做迁移垫片。曾在 `<cwd>/.storages` 下缓存过的部署要么全部重新派生（工作区从 header 索引重新 bootstrap；投影缓存惰性重折），要么手动把两个 json 文件挪一次。
+
+### 声明派生介质：损坏时重置而非拒绝
+
+- `DomainSpec` 增加 `recovery?: 'reject' | 'reset'`（默认 `'reject'`）。spec 对象已经是一个域的身份与布局的单一来源；其介质是权威还是派生属于同类事实，落在同一处。`session_projcache` 声明 `'reset'`；`workspace` 保持默认。
+- `KvFacet` 增加一个原语：`destroy(descriptor): Promise<void>`——整体移除该 unit 的介质（json：删文件；sqlite：drop 该 unit 的表）。与 `open` 一样，它是后端存储原语，不是策略。
+- `DomainFacility.open` 在 spec 声明 `'reset'` 且 open 恰以损坏类错误失败时——`StorageError('version-mismatch' | 'malformed-medium')` 或 `DomainError('invalid-record')`——记一条命名该域和被丢弃介质的警告，调用 `destroy`，再空开一次。其余一切失败（`backend-not-found`、`facet-unsupported`、`already-open`、I/O 错误）无论声明与否都保持大声：配置错误和环境故障不是介质损坏。重试单发——第二次失败原样传播，持续失败的介质不会成环。
+- 有了这个，缓存域 spec 的 version 字段才获得其本意：bump `version`（或让 zod 拒绝漂移行）真正丢弃整个介质，缓存经正常写点和冷读重建——恢复阶梯的最外一档，与已落地的行级各档对齐。
+
+## Alternatives considered
+
+**保持按启动目录的 `.storages`（现状）**——拒绝：会话是全局的，所以每个从会话派生的介质都与自己的真源劈叉；缓存的动机场景（一次列出全部会话）结构性丢行，工作区注册表索引着从另一个启动目录看不见的会话。
+
+**只把投影缓存的 route 指到全局根，`workspace.json` 留在 per-cwd**——拒绝：工作区注册表有一模一样的全局 vs per-cwd 错位，而且塑造缓存的用户决策就是刻意把它放在 `workspace.json` 旁边——一个 hub 根让介质同址、心智模型单一。
+
+**缓存插件本地恢复（在 `SessionProjectionCache[Service.init]` 捕获损坏错误、删文件、重开）**——拒绝：插件不越过后端抽象就叫不出介质路径，且未来每个派生域都要重抄同一段 catch；facility 是唯一已经在分类 open 失败的地方。
+
+**损坏时退到内存态临时域**——拒绝：进程余生静默降级为仅内存，损坏文件永不自愈；下次启动照样失败。
+
+**把损坏介质改名旁置（`<unit>.json.corrupt-<ts>`）而非删除**——未选：派生介质的损坏字节没有恢复价值（日志才是真源），残骸无界累积；删除才是诚实的操作。若未来某个*权威*域想要重置语义，旁置改名才是对的——这正是 `recovery` 按 spec 声明的理由。
+
+**所有域一律自动重置（不加 spec 字段）**——断然拒绝：`workspace.json` 是权威用户数据；版本 bump 时静默重置会毁掉工作区。权威性是域的属性，必须由其所有者声明。
+
+## Acceptance criteria
+
+- 从任意目录启动 `dsh` 都读写同一份 `$DSH_HOME/storages/*.json`（默认 `~/.dsh/storages`）；profile 键 `storageRoot` 可覆盖；裸 Loader 启动 yml 仍落在相对启动 cwd 的 `./.storages`,并在后端构造时 resolve 一次。
+- `session_projcache.json` 被截断、版本 bump 或 schema 漂移时，组装干净启动：一条警告命名被丢弃的介质，文件消失，缓存经正常运转重建，冷列表列随会话重新 checkpoint 逐步回归。
+- 同样的损坏发生在 `workspace.json` 上仍大声拒绝启动。
+- facility 测试覆盖：每个损坏类恰好重置一次 `'reset'` 域；非损坏失败在 `'reset'` 域上保持大声；`'reject'` 域传播一切失败；`destroy` 在两个出厂后端上都移除介质。
+
+## Risks
+
+- **错误分类失误导致自动删除健康文件。** 由封闭的损坏类清单缓解：重置只在三个确定性解析期代码上触发；ENOENT 本来就是「空 unit」,一切 I/O 错误（EACCES、EIO）大声传播。单发重试把爆炸半径限定为每次 open 至多一删。
+- **根迁移改变既有 checkout 的查找位置。** 在 pre-release 立场下接受（后端拒绝旧格式、无外部消费者）；上文为在乎 per-cwd `workspace.json` 内容的人记录了一次性手动搬移。
+- **`destroy` 是存储 seam 上新增的破坏性原语。** 唯一调用方是 facility 的声明重置路径；后端契约将其记档为 facility 专属,任何面向模型或面向用户的路径都触不到它。