feat(session): persist optional time zones

This commit is contained in:
pku-xht
2026-08-06 05:06:57 +08:00
committed by Tianyi Cui
parent d61059364e
commit a667ec55d6
25 changed files with 516 additions and 70 deletions

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@@ -4,7 +4,7 @@ English | [中文](README.zh.md)
The durable session-persistence Service Definition (`ctx.sessionPersistence`). Defines WHAT a persistence backend does — durably store, reload, and list sessions — without saying HOW. Mirrors the `dsh-bash` capability-seam template ([capability seams](../../../.agents/notes/implemented/architecture/2026-06-13-capability-seams.md)): an abstract service here, a Service provider in a sibling package, and Consumers that inject the service.
The persisted unit IS the existing `SessionEvent` (event-sourced model — the log is the single source of truth), so there is no parallel "persisted message" type. Metadata that is NOT replayable conversation state (format version, cwd, lineage, seed boundary, origin, delegation depth) travels separately as `SessionHeader`, owned by `dsh-session` and re-exported here.
The persisted unit IS the existing `SessionEvent` (event-sourced model — the log is the single source of truth), so there is no parallel "persisted message" type. Metadata that is NOT replayable conversation state (format version, cwd, optional time zone, lineage, seed boundary, origin, delegation depth) travels separately as `SessionHeader`, owned by `dsh-session` and re-exported here.
## Service API (`ctx.sessionPersistence`)
@@ -33,7 +33,9 @@ The persisted unit IS the existing `SessionEvent` (event-sourced model — the l
Each `session/event` copies its event into the session controller. The first pending event starts a fixed batching window; later events join without resetting its deadline. The configured `writeBatchMaxDelayMs` bounds this intentional wait, not event-loop, initialization, serialized-operation, or backend latency. Events admitted during a write form a new bounded batch. `session/flush` cancels the wait and is a shared quiescence barrier that drains events admitted while it runs. A background failure is logged once, retains the ordered batch, and pauses automatic retry; a new event starts a fresh window, while explicit flush or backend teardown retries immediately and surfaces a repeated failure.
Crash repair is cold-only. For a live id, `load(id)` snapshots the authoritative in-memory log, waits for that snapshot to become durable, and returns it only when balanced; an open live turn rejects instead of receiving synthetic interruption closers. For a cold id, inspection reads, validates, freezes, and constructs one unpublished Session; repeated inspection reuses that object graph only while its source revision remains current. `prepare(id)` performs the same check before repair, reserves the exact Session, commits any pending torn-tail/interrupted-turn repair, and returns it for publication. HMR adoption reads through `loadStored`, applies the coordinator's cwd check, and never closes the active turn.
A live controller retains no seed copy. If first initialization rejects, the next flush borrows the current append-only Session log, rechecks the backend's actual cursor, and appends only the missing suffix before draining retained events. Concurrent retries share one initialization attempt; a committed-but-rejected write therefore neither duplicates the prefix nor permanently poisons the Session.
Crash repair is cold-only. For a live id, `load(id)` snapshots the authoritative in-memory log, waits for that snapshot to become durable, and returns it with the coordinator's stored header only when balanced; an open live turn rejects instead of receiving synthetic interruption closers. For a cold id, inspection reads, validates, freezes, and constructs one unpublished Session; repeated inspection reuses that object graph only while its source revision remains current. `prepare(id)` performs the same check before repair, reserves the exact Session, commits any pending torn-tail/interrupted-turn repair, and returns it for publication. HMR adoption reads through `loadStored`, compares cwd and any stored `timeZone`, and never closes the active turn. A stored header without `timeZone` is the compatibility exception: a zoned live object may adopt it, but the stored header remains headerless and is never backfilled.
Backend reads normalize the exact supported same-version shapes before current-shape validation. Pre-identity messages receive the deterministic id `legacy-message:<session-id>:<event-seq>`; a tool-result content replacement inherits its target's imported id. A pre-react-loop `turn/start` loses its obsolete trigger, a removed `steering/message` becomes the same identified `user/message`, and an older `turn/end` maps its terminal reason without inventing a caller that the old record did not name. The coordinator uses the same normalized view for `load`, `inspect`, `readFrom`, ownerless-state claims, and HMR prefix adoption. Storage remains append-only: reads do not rewrite old records, and later appends use the current shape. These are narrow import exceptions from the [pre-identity message](../../../.agents/notes/implemented/bug-fix/2026-07-28-load-pre-identity-session-messages.md) and [pre-react-loop session](../../../.agents/notes/implemented/bug-fix/2026-08-04-load-pre-react-loop-sessions.md) decisions, not a general v0 migration promise.
@@ -54,11 +56,11 @@ The `PersistenceBackend<TornMarker>` hooks (the only contract between the coordi
| `list(signal?)` | List all stored metadata, observing optional cancellation. |
| `close?()` | Optional lifecycle teardown (e.g. close a db handle), awaited after the dispose drain. |
The coordinator asserts the stored id and compares stored/live cwd before repair or live adoption. Its `inspect()` path takes ownership of fresh backend values, validates and freezes them once, and retains at most the configured number of unpublished Sessions without calling `commitRepair`. A retained source is reused or repaired only when its revision still equals `readStoredRevision`; otherwise the coordinator reloads it. This freshness check does not add cross-process writer exclusion. Revision retries converge when the durable log remains unchanged for one read/check round trip; continuous external writers can delay `load`, `inspect`, or `prepare`. The `tornMarker` is fully OPAQUE: the coordinator only tests `!== undefined` and round-trips it to `commitRepair`, never inspecting its value (the JSONL backend uses the byte offset to truncate to, the SQLite backend the seq to delete from). A third-party backend MAY implement the abstract service directly without the coordinator, but it must provide the same non-mutating inspection and trustworthy lightweight snapshot revisions. See [the write-coordinator Agent Note](../../../.agents/notes/implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md).
The coordinator asserts the stored id and validates the optional stored `timeZone` as a string before repair or publication. Live adoption compares stored/live cwd and requires an exact live match when the stored header has a zone; an absent stored zone remains absent. Its `inspect()` path takes ownership of fresh backend values, validates and freezes them once, and retains at most the configured number of unpublished Sessions without calling `commitRepair`. A retained source is reused or repaired only when its revision still equals `readStoredRevision`; otherwise the coordinator reloads it. This freshness check does not add cross-process writer exclusion. Revision retries converge when the durable log remains unchanged for one read/check round trip; continuous external writers can delay `load`, `inspect`, or `prepare`. The `tornMarker` is fully OPAQUE: the coordinator only tests `!== undefined` and round-trips it to `commitRepair`, never inspecting its value (the JSONL backend uses the byte offset to truncate to, the SQLite backend the seq to delete from). A third-party backend MAY implement the abstract service directly without the coordinator, but it must provide the same non-mutating inspection and trustworthy lightweight snapshot revisions. See [the write-coordinator Agent Note](../../../.agents/notes/implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md).
## Metadata and location types
Re-exported from `dsh-session`: `SessionHeader` (immutable session metadata: `version`, `id`, `createdAt`, `cwd?`, `parentSession?`, `seedLength?`, `origin?`, `delegationDepth?`). `SessionLocation` is `{ readonly kind: string; readonly path: string }`; its path is an absolute backend target, not proof that the artifact exists or contains an unflushed turn.
Re-exported from `dsh-session`: `SessionHeader` (immutable session metadata: `version`, `id`, `createdAt`, `cwd?`, `timeZone?`, `parentSession?`, `seedLength?`, `origin?`, `delegationDepth?`). `SessionLocation` is `{ readonly kind: string; readonly path: string }`; its path is an absolute backend target, not proof that the artifact exists or contains an unflushed turn.
## Model Experience