Merge commit 'refs/codex-unblock/20260723/pr570-master-initial' into worktree/pr570-merge-master-20260723

# Conflicts:
#	.agents/notes/implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md
#	docs/core-data-structures/persistence.md
#	packages/session-persistence/session-persistence/README.md
This commit is contained in:
Tianyi Cui
2026-07-23 23:21:08 +08:00
366 changed files with 11617 additions and 1027 deletions

View File

@@ -2,7 +2,7 @@
The **durability seam** for the event log. [session.md](session.md) describes the in-memory `Session` — the append-only `SessionEvent` log that is the source of truth. This page describes how that log is made durable: the abstract `SessionPersistence` service, its backends, the flush checkpoint, crash recovery, and the metadata header that travels alongside the log. The event vocabulary the log carries is enumerated, member by member, in the generated [persistence log event catalog](../persistence-catalog.md).
The seam is a textbook [capability seam](../../.agents/notes/implemented/architecture/2026-06-13-capability-seams.md): one abstract service ([dsh-session-persistence](../../packages/session-persistence/session-persistence), `ctx.sessionPersistence`) defining locate/create/append/load/list over the existing `SessionEvent`**no parallel persisted type** — and two interchangeable backends that pass the same `runPersistenceContract` suite. See the [session-persistence Agent Note](../../.agents/notes/implemented/architecture/2026-06-14-session-persistence.md).
The seam is a textbook [capability seam](../../.agents/notes/implemented/architecture/2026-06-13-capability-seams.md): one abstract service ([dsh-session-persistence](../../packages/session-persistence/session-persistence), `ctx.sessionPersistence`) defining locate/create/append, crash-repairing load, non-mutating inspect, and lightweight list/snapshot observation over the existing `SessionEvent`**no parallel persisted type** — and two interchangeable backends that pass the same `runPersistenceContract` suite. See the [session-persistence Agent Note](../../.agents/notes/implemented/architecture/2026-06-14-session-persistence.md).
## The flush checkpoint
@@ -14,6 +14,8 @@ A backend that reloads a log crashed mid-turn finds an open `turn/start` with no
Repair applies only to cold sessions. For a live id, `SessionPersistence.load(id)` snapshots the in-memory log, waits until that snapshot is durable, and returns it with the stored header only when balanced; an open live turn rejects rather than receiving synthetic interruption boundaries. A coordinator-backed cold load reserves the id across backend reads and repair writes, so concurrent publication of a same-id live session rejects and rolls back. HMR also adopts a live prefix without closing its active turn.
`SessionPersistence.inspect(id)` is the observer counterpart to recovery: it returns a detached valid stored prefix without truncating a torn record, adding interruption closers, or publishing write state. Same-id serialization keeps it coherent with backend writes. Derived read models use `inspect`, never `load`, so observing a checkpointed open turn cannot mutate the log if live ownership begins concurrently.
## `SessionLocation` — optional per-session artifact target
`SessionPersistence.locate(meta)` synchronously resolves a backend-owned independent artifact without reading, creating, or flushing it. JSONL returns its absolute target path; SQLite returns `undefined` because sessions share one database. A returned path can therefore name a file that does not yet exist or lacks the current unflushed turn; it is a location hint, not authorization or a freshness guarantee.
@@ -100,9 +102,31 @@ interface CreateSessionOptions {
Replay/fork is therefore `ctx.sessions.create(id, { seed: seedEvents })`; resuming a *persisted* session into a live agent is `ctx.agents.resume({ resumeSessionId })`.
## Lightweight source revisions
Consumers of derived state compare a cheap opaque revision before loading a full event log. The persistence backend owns its representation and changes it transactionally with append or mutating load repair; callers compare it only for equality.
```ts type-equiv
/**
* Backend-owned token that identifies both one storage source and one revision
* of a persisted session log.
*/
type SessionPersistenceRevision = Branded<'SessionPersistenceRevision'>
```
```ts type-equiv
/** Lightweight immutable source identity returned without loading a full log. */
interface SessionPersistenceSnapshot {
/** Detached metadata for one materialized session. */
header: SessionHeader
/** Opaque source-qualified token that changes whenever this stored log changes. */
revision: SessionPersistenceRevision
}
```
## The backends
Both implement the same abstract `SessionPersistence` (locate/create/append/load/list over `SessionEvent`) and pass `runPersistenceContract`, proving the seam is genuinely backend-agnostic:
Both implement the same abstract `SessionPersistence` (locate/create/append/load/inspect/list/listSnapshots over `SessionEvent`) and pass `runPersistenceContract`, proving the seam is genuinely backend-agnostic:
- **[dsh-session-persistence-jsonl](../../packages/session-persistence/session-persistence-jsonl)** — an append-only logical JSONL log per session, stored as checksummed concatenated Zstandard frames by default or raw lines by configuration, with crash-safe atomic writes, interrupted-turn recovery, and a read/replay path.
- **[dsh-session-persistence-sqlite](../../packages/session-persistence/session-persistence-sqlite)** — `node:sqlite`, one row per `SessionEvent`. The row shape `(session_id, seq, type, time, data, source_event_seqs, surface_op)` maps 1:1 onto the event, including optional surface metadata, so there is no parallel persisted schema to keep in sync.