feat(session-persistence): abstract seam + JSONL backend + wiring

Add the durable session-persistence capability seam (ADR 0016): an
abstract SessionPersistence service (dsh-session-persistence,
ctx.sessionPersistence) defining create/append/load/list/has/delete/
update over the existing SessionEvent — no parallel persisted type — and
a first implementation (dsh-session-persistence-jsonl): an append-only
JSONL log per session with crash-safe atomic writes, truncation-repair
of a never-committed crash tail, and a read/replay path. SessionMeta
(format version, cwd, lineage) travels out-of-log via session.header.

A shared runPersistenceContract suite holds every backend to the same
append-only / contiguous-seq / lazy-materialization / serializability
semantics.

Config-driven create() now uses a per-run ${id}-session-<uuid> session
id so a fixed name no longer collides with an on-disk log once a durable
backend is loaded; each run is a new session (a demo simplification). The
examples drop their hand-rolled session-jsonl.ts and load the JSONL
backend via cordis.yml; CI smoke-loads it too.

The agent-facing create/resume factory that consumes load() is a
separate seam, deferred to a follow-up; this change stops at the load
primitive and does not reach into the loop.
This commit is contained in:
Tianyi Cui
2026-06-15 21:05:46 +08:00
parent b0bc0b5792
commit df4b7d3d9a
33 changed files with 2959 additions and 89 deletions

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@@ -69,5 +69,7 @@ jobs:
echo "$out" echo "$out"
echo "$out" | grep -q '\[tool call\] echo({"text":"ci smoke"})' echo "$out" | grep -q '\[tool call\] echo({"text":"ci smoke"})'
echo "$out" | grep -q '\[tool result\] ECHO: CI SMOKE' echo "$out" | grep -q '\[tool result\] ECHO: CI SMOKE'
test -f examples/echo-agent/main-session.jsonl # The JSONL backend (root ./.sessions, no cwd → _no-cwd bucket) writes a
rm -f examples/echo-agent/*.jsonl # per-run session log named main-session-<uuid>.jsonl. Assert one exists.
ls .sessions/_no-cwd/main-session-*.jsonl >/dev/null
rm -rf .sessions

2
.gitignore vendored
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@@ -6,6 +6,8 @@ lib/
.yarn/ .yarn/
yarn-error.log yarn-error.log
examples/*/*.jsonl examples/*/*.jsonl
.sessions/
examples/*/.sessions/
coverage/ coverage/
.doc-typecheck-*/ .doc-typecheck-*/
.vscode/ .vscode/

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@@ -0,0 +1,30 @@
# ADR 0016: Session persistence as an abstract service over the existing `SessionEvent`
Status: accepted (2026-06-15)
## Context
Sessions lived only in memory. The example `session-jsonl.ts` plugin (duplicated byte-for-byte in both examples) was write-only telemetry: it buffered `session/event` and appended JSON lines, with no read/replay path, no crash-safety (no fsync, no atomic write, a fire-and-forget dispose drain), no listing, and no format versioning. Nothing could rehydrate a past session from disk into a live agent, so durable resume ("continue yesterday's task"), durable forking, and the ACP `session/load` method (RFC 010) were all impossible.
The [event-sourced model](0003-event-sourced-sessions.md) makes the append-only log the single source of truth and derives LLM history from it. Persistence had to stay faithful to that: persist the existing `SessionEvent` directly, with no parallel "persisted message" type that the log is converted to and from. The backend also had to be swappable — a file store now, a database store later — behind one interface.
## Decision
Persistence is an abstract **capability seam** ([ADR 0009](0009-capability-seams.md), the `dsh-bash` template), not loop or core logic:
1. **Interface** (`dsh-session-persistence`, `ctx.sessionPersistence`) — an abstract `SessionPersistence` service: `create`/`append`/`load`/`list`/`has`/`delete`/`update`. Its persisted unit IS the existing `SessionEvent` (`{ type, seq, time, data }`), reused verbatim — no conversion type.
2. **Implementation** (`dsh-session-persistence-jsonl`) — an append-only JSONL log per session (a `SessionHeader` line then one `SessionEvent` per line, verbatim **including `assistant/chunk`**) plus an atomic `.summary.json` sidecar for the mutable `SessionSummary`.
Key choices recorded here because they are durable, contested, and surprising:
- **The canonical durable log persists every `SessionEvent` verbatim, including `assistant/chunk`.** `deriveMessages()` skips chunks, and a chunk-filtered rollout (Codex's `policy.rs`) is tempting — but `seq = log.length` and the load-validation `events[i].seq === i` require a *contiguous* log; filtering chunks out would leave holes and break both the contract and resume. A chunk-filtered projection is possible later as a derived view with its own renumbering, but it is NOT the canonical log.
- **Append-only with a single exception.** Committed events — those at or below a flushed `turn/end` — are never rewritten. The loop only flushes at `turn/end`, so a crash can leave a half-written final turn below the last checkpoint; `load` returns events only up to the **last complete `turn/end`**, and the first post-load `append` runs a one-time **truncation-repair** (`ftruncate` + `fsync`) that physically discards only that never-committed crash tail before writing.
- **File backend canonical, DB backend a drop-in.** `SessionEvent` maps 1:1 onto a row `(session_id, seq, type, time, data)` — `append` is INSERT (in a transaction asserting the contiguous-seq contract), `load` is SELECT … ORDER BY seq. A future `dsh-session-persistence-sqlite` is a `SessionPersistence` subclass with no interface change (opencode runs this exact shape on SQLite/WAL).
- **Metadata is out-of-log.** Format version, cwd, and lineage are storage concerns, not replayable conversation state, so they live in a `SessionMeta` (`SessionHeader & SessionSummary`) owned by `dsh-session` and attached to a `Session` via a new readonly `session.header` — never in `SessionEventMap`, never reaching `deriveMessages()`. The alternative (a merge-extensible `session/meta` event as log line 0) was rejected: an in-log event would ride along with a seeded/forked session for free, but metadata is not replayable state, so the explicit out-of-log header seam is the cleaner cost.
- **`load` returns a resumable event log, not just bytes.** `load(sessionId)` yields the `SessionMeta` plus the committed `SessionEvent[]` (through the last complete `turn/end`), shaped so a caller can reconstruct a live session with the loaded events as seed (so `lastTurnNumber`/`deriveMessages` continue) on the SAME session id. The agent-facing create/resume factory that consumes this is a separate seam (a follow-up on `ctx.agents`); the persistence layer deliberately stops at the `load` primitive and does NOT reach into the loop. The agent-loop does NOT hard-inject `sessionPersistence` (that would pend non-persistent demos forever), so any resume path built on this rejects with a typed error when the backend is absent.
Format versioning: the header carries a `version`; `load` rejects an unknown version (no v1 migration). Stated honestly: append-only + flush is robust to partial trailing writes (tolerated on load) but not to fsync-less power loss mid-line; a DB/WAL backend is the stronger option later.
## Consequences
Two new packages and the metadata seam in `dsh-session` (`session.header`, the `create(id?, options?)` signature). Bought: durable resume/fork, a read/replay path, crash tolerance, and the foundation RFC 010's `session/load` needs — all over the existing event-sourced log, with the backend swappable behind one interface. The reusable `runPersistenceContract` suite holds every backend to the same append-only / contiguous-seq / lazy-materialization / serializability semantics. This completes [ADR 0003](0003-event-sourced-sessions.md)'s deferred "real persistence backend" and resolves its `TODO(review)` on the event vocabulary: persisting the log freezes its shape, and the `assistant/chunk` fidelity question is answered above (persist verbatim).

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@@ -27,4 +27,5 @@ Do NOT write an ADR for: a mechanical or local choice (a variable name, a one-fi
| [0013](0013-property-based-testing.md) | Property-based testing for protocol-shaped code | accepted | | [0013](0013-property-based-testing.md) | Property-based testing for protocol-shaped code | accepted |
| [0014](0014-doc-sync-enforcement.md) | Doc-sync enforcement (doc code blocks + event taxonomy) | accepted | | [0014](0014-doc-sync-enforcement.md) | Doc-sync enforcement (doc code blocks + event taxonomy) | accepted |
| [0015](0015-structured-error-taxonomy.md) | Structured error taxonomy (HarnessError base) | accepted | | [0015](0015-structured-error-taxonomy.md) | Structured error taxonomy (HarnessError base) | accepted |
| [0016](0016-session-persistence.md) | Session persistence as an abstract service over `SessionEvent` | accepted |
| [0017](0017-turn-enclosure-invariant.md) | Every session event is enclosed in a turn | accepted | | [0017](0017-turn-enclosure-invariant.md) | Every session event is enclosed in a turn | accepted |

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@@ -22,11 +22,13 @@ Requirement context: [Coding Harness MVP 需求分析][mvp-doc].
│ @deepseek-ai/dsh-agent-loop (the ONE concrete plugin) │ │ @deepseek-ai/dsh-agent-loop (the ONE concrete plugin) │
│ @deepseek-ai/dsh-bash-local (bash impl) │ │ @deepseek-ai/dsh-bash-local (bash impl) │
│ @deepseek-ai/dsh-tool-bash (bash tool schemas) │ │ @deepseek-ai/dsh-tool-bash (bash tool schemas) │
│ @deepseek-ai/dsh-session-persistence-jsonl (persistence impl)│
├─────────────────────────────────────────────────────────────┤ ├─────────────────────────────────────────────────────────────┤
│ @deepseek-ai/dsh-agent (vocabulary + registry) │ │ @deepseek-ai/dsh-agent (vocabulary + registry) │
│ @deepseek-ai/dsh-tools (registry + exec waterfall)│ │ @deepseek-ai/dsh-tools (registry + exec waterfall)│
│ @deepseek-ai/dsh-system-prompt (assembly registry) │ │ @deepseek-ai/dsh-system-prompt (assembly registry) │
│ @deepseek-ai/dsh-session (event-sourced log) │ │ @deepseek-ai/dsh-session (event-sourced log) │
│ @deepseek-ai/dsh-session-persistence (persistence seam) │
│ @deepseek-ai/dsh-llm (abstract model service) │ │ @deepseek-ai/dsh-llm (abstract model service) │
│ @deepseek-ai/dsh-bash (abstract bash executor) │ │ @deepseek-ai/dsh-bash (abstract bash executor) │
├─────────────────────────────────────────────────────────────┤ ├─────────────────────────────────────────────────────────────┤
@@ -43,6 +45,7 @@ Dependency rule: plugins depend on interface packages, never on `dsh-agent-loop`
|---|---|---|---| |---|---|---|---|
| `ctx.llm` | `LlmService` | dsh-llm | adapter registry; `stream()` / `streamBlocks()` / `generate()` | | `ctx.llm` | `LlmService` | dsh-llm | adapter registry; `stream()` / `streamBlocks()` / `generate()` |
| `ctx.sessions` | `SessionStore` | dsh-session | creates/holds event-sourced `Session`s | | `ctx.sessions` | `SessionStore` | dsh-session | creates/holds event-sourced `Session`s |
| `ctx.sessionPersistence` | `SessionPersistence` (abstract) | dsh-session-persistence | durable persistence seam: create/append/load/list/update sessions |
| `ctx.systemPrompt` | `SystemPrompt` | dsh-system-prompt | ordered sections + tool schemas → `assemble()` | | `ctx.systemPrompt` | `SystemPrompt` | dsh-system-prompt | ordered sections + tool schemas → `assemble()` |
| `ctx.tools` | `ToolRegistry` | dsh-tools | tool definitions; `execute()` through waterfall | | `ctx.tools` | `ToolRegistry` | dsh-tools | tool definitions; `execute()` through waterfall |
| `ctx.agents` | `AgentRegistry` | dsh-agent | live `Agent` handles | | `ctx.agents` | `AgentRegistry` | dsh-agent | live `Agent` handles |
@@ -92,7 +95,7 @@ A `Session` is an append-only log of typed `SessionEvent`s — the single source
Replay/fork = `ctx.sessions.create(id, { seed: seedEvents })`. Trace/telemetry = listen to `session/event`. Replay/fork = `ctx.sessions.create(id, { seed: seedEvents })`. Trace/telemetry = listen to `session/event`.
**Durability seam**: `session/event` is a synchronous notification; persistence plugins buffer (write-behind) and drain at the awaited `session/flush` checkpoint the loop fires at every turn end (see `examples/echo-agent/src/session-jsonl.ts` for the pattern). **TODO**: real persistence backends (JSONL per session dir, sqlite) are a future phase. **Durability seam**: `session/event` is a synchronous notification; persistence plugins buffer (write-behind) and drain at the awaited `session/flush` checkpoint the loop fires at every turn end. The durable backend is a real **capability seam**: the abstract `SessionPersistence` service (`dsh-session-persistence`, `ctx.sessionPersistence`) defines create/append/load/list/update over the existing `SessionEvent` (no parallel persisted type), and `dsh-session-persistence-jsonl` is the first implementation — an append-only JSONL log per session with crash-safe atomic writes, truncation-repair of a never-committed crash tail, and a read/replay path. Session metadata (format version, cwd, lineage) travels separately as `SessionMeta`, attached to a `Session` via `session.header`. `ctx.sessionPersistence.load(sessionId)` returns the committed event log so a caller can reconstruct a live session and continue it. A SQLite/WAL backend is a future drop-in `SessionPersistence` subclass (the row shape `(session_id, seq, type, time, data)` maps 1:1 onto `SessionEvent`).
## Prompt assembly (dsh-system-prompt) ## Prompt assembly (dsh-system-prompt)
@@ -162,7 +165,7 @@ forever:
Error containment: a throwing `agent/turn-continuation` listener or a broken step ends the **turn** with an `error` event (appended INSIDE the turn, before `turn/end`) — never the driver loop. An adapter that ends its stream with a `finish {kind:'error'}` or `{kind:'aborted'}` chunk (the in-band error path, for adapters that can't throw mid-stream) is likewise translated into a step error, so the turn ends `error`/`aborted` instead of logging a normal `completed` assistant message. `abort()` is honored mid-stream **and** between tool calls; disposal mid-turn ends the turn with reason `disposed` and emits `agent/status('disposed')`. Error containment: a throwing `agent/turn-continuation` listener or a broken step ends the **turn** with an `error` event (appended INSIDE the turn, before `turn/end`) — never the driver loop. An adapter that ends its stream with a `finish {kind:'error'}` or `{kind:'aborted'}` chunk (the in-band error path, for adapters that can't throw mid-stream) is likewise translated into a step error, so the turn ends `error`/`aborted` instead of logging a normal `completed` assistant message. `abort()` is honored mid-stream **and** between tool calls; disposal mid-turn ends the turn with reason `disposed` and emits `agent/status('disposed')`.
A failure that happens once the turn is already closed has no in-turn position for a session `error` event (appending one after `turn/end` would put it past a persistence backend's commit boundary, where it is dropped as a crash tail — ADR 0017). So a rejecting `session/flush` (the post-`turn/end` durability checkpoint) and a throwing `agent/turn-end` listener are reported via `agent/error` + the logger only, NOT as a session event; the turn stays balanced and the backend keeps its buffered events for the next flush. A failure that happens once the turn is already closed has no in-turn position for a session `error` event (appending one after `turn/end` would put it past the persistence commit boundary, where it is dropped as a crash tail — ADR 0017). So a rejecting `session/flush` (the post-`turn/end` durability checkpoint) and a throwing `agent/turn-end` listener are reported via `agent/error` + the logger only, NOT as a session event; the turn stays balanced and the persistence backend keeps its buffered events for the next flush.
**Turn-enclosure invariant**: every session event lives inside a turn (between a `turn/start` and its `turn/end`). The loop appends queued `user/message` events *after* `turn/start`, and an idle `agent.inject()` wraps its `context/message` in a one-shot `injection` turn. This makes the turn the single durability/replay boundary: a persistence backend can treat anything after the last `turn/end` as an interrupted-crash tail without risking the loss of legitimately-recorded between-turn context. The `dsh-invariants` plugin enforces it in dev (a message event outside an open turn throws). See ADR 0017. **Turn-enclosure invariant**: every session event lives inside a turn (between a `turn/start` and its `turn/end`). The loop appends queued `user/message` events *after* `turn/start`, and an idle `agent.inject()` wraps its `context/message` in a one-shot `injection` turn. This makes the turn the single durability/replay boundary: a persistence backend can treat anything after the last `turn/end` as an interrupted-crash tail without risking the loss of legitimately-recorded between-turn context. The `dsh-invariants` plugin enforces it in dev (a message event outside an open turn throws). See ADR 0017.
@@ -238,8 +241,7 @@ Code skeletons for the three plugin shapes (tool, hook/permission-gate, UI) and
Tracked here deliberately — each is designed-for but not implemented: Tracked here deliberately — each is designed-for but not implemented:
- **Sub-agent spawn/fork semantics** (seam: `AgentLoop.create()`); inter-agent channels beyond `send`/`steer`/events. - **Sub-agent spawn/fork semantics** (seam: `AgentLoop.create()`); inter-agent channels beyond `send`/`steer`/events.
- **Persistence backends** (JSONL session dirs, sqlite) on the `session/event` + `session/flush` seam. - **SQLite/WAL persistence backend** — a drop-in `SessionPersistence` subclass (the abstract seam + the JSONL backend landed; see the durability-seam paragraph).
- **Compaction implementation** (auto thresholds, summarization prompts) on the `agent/request` seam, with its session-event types added by declaration merging. - **Compaction implementation** (auto thresholds, summarization prompts) on the `agent/request` seam, with its session-event types added by declaration merging.
- **Parallel tool execution** (concurrency-safety hints on ToolDefinition). - **Parallel tool execution** (concurrency-safety hints on ToolDefinition).
- **Session branching/tree** (pi-style entry tree) if needed beyond seed-based forking. - **Session branching/tree** (pi-style entry tree) if needed beyond seed-based forking.
- **Session event vocabulary review** once the loop and a persistence plugin coexist (`TODO(review)` in dsh-session).

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@@ -1,6 +1,6 @@
# RFC 009: Durable session persistence — an abstract, append-only, event-based store # RFC 009: Durable session persistence — an abstract, append-only, event-based store
Status: proposed Status: implemented (see [ADR 0016](../adr/0016-session-persistence.md))
## Problem ## Problem

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@@ -29,7 +29,7 @@ Type a coding task. The agent's only tools are `bash` (+ `bash_output` / `bash_k
| `llm-deepseek` | real `LlmAdapter` via config (`!!js process.env.…` secrets); swap one line to `@deepseek-ai/dsh-llm-pi-ai` for the library-backed twin | | `llm-deepseek` | real `LlmAdapter` via config (`!!js process.env.…` secrets); swap one line to `@deepseek-ai/dsh-llm-pi-ai` for the library-backed twin |
| `bash` (`dsh-bash-local`) + `tool-bash` | the executor seam + tool schemas as separate plugins | | `bash` (`dsh-bash-local`) + `tool-bash` | the executor seam + tool schemas as separate plugins |
| `agent-loop` | agent created from config with a coding system prompt | | `agent-loop` | agent created from config with a coding system prompt |
| `src/session-jsonl.ts` | write-behind persistence on `session/event` + `session/flush` (copied from echo-agent) | | `session-persistence` (`dsh-session-persistence-jsonl`) | durable JSONL persistence (`root: ./.sessions`): append-only event log per session, crash-safe atomic writes — the shared backend, no per-example file |
| `src/stdio-chat.ts` | UI as a plugin; copied from echo-agent with reasoning-dimming and an exit-on-idle close handler for piped stdin. Example-local on purpose — extract a shared UI package when a third example needs it | | `src/stdio-chat.ts` | UI as a plugin; copied from echo-agent with reasoning-dimming and an exit-on-idle close handler for piped stdin. Example-local on purpose — extract a shared UI package when a third example needs it |
## End-to-end tests (`yarn test:e2e`, key-gated) ## End-to-end tests (`yarn test:e2e`, key-gated)

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@@ -74,8 +74,10 @@
failures before moving on. Verify your work by running the code or failures before moving on. Verify your work by running the code or
tests. Keep answers brief and factual. tests. Keep answers brief and factual.
- id: session-jsonl - id: session-persistence
name: './src/session-jsonl.ts' name: '@deepseek-ai/dsh-session-persistence-jsonl'
config:
root: './.sessions'
- id: stdio-chat - id: stdio-chat
name: './src/stdio-chat.ts' name: './src/stdio-chat.ts'

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@@ -1,36 +0,0 @@
import { appendFile } from 'node:fs/promises'
import { join } from 'node:path'
import type { Context } from 'cordis'
import type { Session, SessionEvent } from '@deepseek-ai/dsh-session'
export const name = 'session-jsonl'
export const inject = ['sessions']
/**
* Minimal persistence plugin: buffers session events (write-behind) and
* drains to a JSONL file at every `session/flush` checkpoint — the pattern a
* real JSONL/sqlite persistence plugin would follow.
*/
export function apply(ctx: Context) {
const buffers = new Map<Session, SessionEvent[]>()
const path = (session: Session) => join(import.meta.dirname, '..', `${session.id}.jsonl`)
ctx.on('session/event', (session, event) => {
let buffer = buffers.get(session)
if (!buffer) buffers.set(session, buffer = [])
buffer.push(event)
})
const flush = async (session: Session) => {
const buffer = buffers.get(session)
if (!buffer?.length) return
const lines = buffer.splice(0).map(event => JSON.stringify(event) + '\n').join('')
await appendFile(path(session), lines)
}
ctx.on('session/flush', flush)
ctx.effect(() => () => {
// drain remaining buffers on dispose
for (const session of buffers.keys()) void flush(session)
}, 'session-jsonl')
}

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@@ -7,7 +7,7 @@ Runnable demo: stdin chat with a scripted mock model and an echo tool.
- A complete Cordis app loaded from `cordis.yml` — the standard "stack of plugins" pattern - A complete Cordis app loaded from `cordis.yml` — the standard "stack of plugins" pattern
- `mock-llm.ts` — a mock `LlmAdapter` that streams scripted responses and calls the `echo` tool when the user types "echo <something>" - `mock-llm.ts` — a mock `LlmAdapter` that streams scripted responses and calls the `echo` tool when the user types "echo <something>"
- `echo-tool.ts` — a tool registered via `ctx.tools.register()` that echoes text back uppercased - `echo-tool.ts` — a tool registered via `ctx.tools.register()` that echoes text back uppercased
- `session-jsonl.ts` — a minimal persistence plugin: write-behind buffering of `session/event` notifications, drained to a JSONL file at `session/flush` - `@deepseek-ai/dsh-session-persistence-jsonl` — the durable JSONL persistence backend (loaded from `cordis.yml`, `root: ./.sessions`): append-only event log per session with crash-safe atomic writes, replacing the old write-only example plugin
- `stdio-chat.ts` — a minimal UI plugin: reads stdin lines and `send`/`steer`s the agent, renders stream deltas, tool calls, and tool results - `stdio-chat.ts` — a minimal UI plugin: reads stdin lines and `send`/`steer`s the agent, renders stream deltas, tool calls, and tool results
## Plugin files ## Plugin files
@@ -16,10 +16,11 @@ Runnable demo: stdin chat with a scripted mock model and an echo tool.
|---|---|---| |---|---|---|
| `mock-llm.ts` | `LlmAdapter` registration | `ctx.llm.registerAdapter(['mock-echo'], …)`, streaming chunks with proper `block-start`/`block-end` protocol | | `mock-llm.ts` | `LlmAdapter` registration | `ctx.llm.registerAdapter(['mock-echo'], …)`, streaming chunks with proper `block-start`/`block-end` protocol |
| `echo-tool.ts` | Tool registration | `ctx.tools.register(defineTool(…))` with typed `execute` args, tool execution returning `ContentBlock[]` | | `echo-tool.ts` | Tool registration | `ctx.tools.register(defineTool(…))` with typed `execute` args, tool execution returning `ContentBlock[]` |
| `session-jsonl.ts` | Persistence | `session/event` listener + `session/flush` drain, fiber-dispose cleanup |
| `stdio-chat.ts` | UI | `agent/stream-chunk`, `session/event` (tool/*), stdin→send/steer | | `stdio-chat.ts` | UI | `agent/stream-chunk`, `session/event` (tool/*), stdin→send/steer |
| `start.ts` | Bootstrap | `Context` + `Loader` + `plugin-include` wired to `cordis.yml` | | `start.ts` | Bootstrap | `Context` + `Loader` + `plugin-include` wired to `cordis.yml` |
Persistence is the shared `@deepseek-ai/dsh-session-persistence-jsonl` plugin (not a per-example file).
## Run ## Run
```sh ```sh
@@ -30,4 +31,4 @@ node --expose-internals --import tsx examples/echo-agent/start.ts
Type a message and press Enter. "echo <text>" triggers a tool call round-trip (the mock model requests the `echo` tool, which echoes the text uppercased, and the next model step acknowledges it). Type a message and press Enter. "echo <text>" triggers a tool call round-trip (the mock model requests the `echo` tool, which echoes the text uppercased, and the next model step acknowledges it).
The session is persisted to `<session-id>.jsonl` in the `examples/echo-agent/` directory. Clean up with: `rm -f examples/echo-agent/*.jsonl` The session is persisted under `examples/echo-agent/.sessions/` (per-cwd subdirectory, one `.jsonl` log per session). Clean up with: `rm -rf examples/echo-agent/.sessions`

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@@ -46,8 +46,10 @@
- id: echo-tool - id: echo-tool
name: './src/echo-tool.ts' name: './src/echo-tool.ts'
- id: session-jsonl - id: session-persistence
name: './src/session-jsonl.ts' name: '@deepseek-ai/dsh-session-persistence-jsonl'
config:
root: './.sessions'
- id: stdio-chat - id: stdio-chat
name: './src/stdio-chat.ts' name: './src/stdio-chat.ts'

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@@ -1,36 +0,0 @@
import { appendFile } from 'node:fs/promises'
import { join } from 'node:path'
import type { Context } from 'cordis'
import type { Session, SessionEvent } from '@deepseek-ai/dsh-session'
export const name = 'session-jsonl'
export const inject = ['sessions']
/**
* Minimal persistence plugin: buffers session events (write-behind) and
* drains to a JSONL file at every `session/flush` checkpoint — the pattern a
* real JSONL/sqlite persistence plugin would follow.
*/
export function apply(ctx: Context) {
const buffers = new Map<Session, SessionEvent[]>()
const path = (session: Session) => join(import.meta.dirname, '..', `${session.id}.jsonl`)
ctx.on('session/event', (session, event) => {
let buffer = buffers.get(session)
if (!buffer) buffers.set(session, buffer = [])
buffer.push(event)
})
const flush = async (session: Session) => {
const buffer = buffers.get(session)
if (!buffer?.length) return
const lines = buffer.splice(0).map(event => JSON.stringify(event) + '\n').join('')
await appendFile(path(session), lines)
}
ctx.on('session/flush', flush)
ctx.effect(() => () => {
// drain remaining buffers on dispose
for (const session of buffers.keys()) void flush(session)
}, 'session-jsonl')
}

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@@ -8,7 +8,7 @@ This is the only package in the harness that contains concrete loop logic. Every
### Public API ### Public API
- `ctx.agentLoop.create(id: string, options?: AgentOptions): LoopAgent` Create an agent, start its loop, and register it in `ctx.agents`. Disposed with the calling fiber. - `ctx.agentLoop.create(id: string, options?: AgentOptions): LoopAgent` — create an agent on a fresh per-run session id `${id}-session-<uuid>`, start its loop, and register it in `ctx.agents`. The per-run uuid avoids colliding with the on-disk log a prior run materialized once a durable persistence backend is loaded; each run is a new session (a deliberate demo simplification — a real resume-or-create policy is a TODO). Disposed with the calling fiber.
### Injected services ### Injected services

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@@ -35,6 +35,7 @@
"@deepseek-ai/dsh-invariants": "^0.0.1", "@deepseek-ai/dsh-invariants": "^0.0.1",
"@deepseek-ai/dsh-llm": "^0.0.1", "@deepseek-ai/dsh-llm": "^0.0.1",
"@deepseek-ai/dsh-session": "^0.0.1", "@deepseek-ai/dsh-session": "^0.0.1",
"@deepseek-ai/dsh-session-persistence-jsonl": "^0.0.1",
"@deepseek-ai/dsh-system-prompt": "^0.0.1", "@deepseek-ai/dsh-system-prompt": "^0.0.1",
"@deepseek-ai/dsh-tools": "^0.0.1", "@deepseek-ai/dsh-tools": "^0.0.1",
"cordis": "^4.0.0-rc.6" "cordis": "^4.0.0-rc.6"

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@@ -8,6 +8,7 @@
*/ */
import { Context, Service } from 'cordis' import { Context, Service } from 'cordis'
import { randomUUID } from 'node:crypto'
import z from 'schemastery' import z from 'schemastery'
import { AgentId } from '@deepseek-ai/dsh-agent' import { AgentId } from '@deepseek-ai/dsh-agent'
import type { AgentOptions } from '@deepseek-ai/dsh-agent' import type { AgentOptions } from '@deepseek-ai/dsh-agent'
@@ -62,12 +63,24 @@ export class AgentLoop extends Service {
* Create an agent, start its loop, and register it. Returns the agent. * Create an agent, start its loop, and register it. Returns the agent.
* Disposed with the calling fiber. * Disposed with the calling fiber.
* *
* The session id is per-run (`${id}-session-<uuid>`, no fixed name): once a
* durable persistence backend is loaded, a fixed `${id}-session` collides on
* the second run — the backend refuses to re-create an id whose log already
* exists on disk (the SessionId is the identity). A fresh id means each run
* is a new session.
*
* TODO(demo): each run starting a brand-new session is fine for demos but is
* NOT real conversation continuity. A production config-driven agent needs a
* deliberate resume-or-create policy (resume the prior session if one exists,
* else start fresh) or an explicit caller-chosen session id — revisit when the
* UI/ACP path owns session selection.
*
* TODO(sub-agents): spawn/fork land here — accept a parent agent reference; * TODO(sub-agents): spawn/fork land here — accept a parent agent reference;
* fork seeds the new Session with the parent's event log, spawn starts * fork seeds the new Session with the parent's event log, spawn starts
* fresh; the child is returned as a regular Agent handle. * fresh; the child is returned as a regular Agent handle.
*/ */
create(id: string, options: AgentOptions = {}): LoopAgent { create(id: string, options: AgentOptions = {}): LoopAgent {
const session = this.ctx.sessions.create(`${id}-session`) const session = this.ctx.sessions.create(`${id}-session-${randomUUID()}`, { meta: {} })
const agent = new LoopAgent(this.ctx, AgentId(id), options, session) const agent = new LoopAgent(this.ctx, AgentId(id), options, session)
// Generator effect: stop and unregister are independent disposables // Generator effect: stop and unregister are independent disposables
// (LIFO), so a throwing stop() cannot leak the registry entry. // (LIFO), so a throwing stop() cannot leak the registry entry.

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@@ -0,0 +1,65 @@
import { afterEach, describe, expect, it } from 'vitest'
import { Context } from 'cordis'
import { mkdtemp, rm } from 'node:fs/promises'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import LlmService from '@deepseek-ai/dsh-llm'
import SessionStore from '@deepseek-ai/dsh-session'
import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
import ToolRegistry from '@deepseek-ai/dsh-tools'
import AgentRegistry from '@deepseek-ai/dsh-agent'
import SessionPersistenceJsonl from '@deepseek-ai/dsh-session-persistence-jsonl'
import AgentLoop, { LoopAgent } from '@deepseek-ai/dsh-agent-loop'
import { MockAdapter, textResponse } from './mock-adapter.ts'
const dirs: string[] = []
afterEach(async () => { for (const d of dirs.splice(0)) await rm(d, { recursive: true, force: true }) })
function waitForIdle(ctx: Context, agent: LoopAgent): Promise<void> {
return new Promise((resolve) => {
const dispose = ctx.on('agent/status', (subject, status) => {
if (subject === agent && status === 'idle') { dispose(); resolve() }
})
})
}
describe('config-driven session id', () => {
it('config-driven create uses a fresh ${id}-session-<uuid> per run (restart-safe)', async () => {
const root = await mkdtemp(join(tmpdir(), 'dsh-cfg-session-'))
dirs.push(root)
const idPattern = /^cfg-session-[0-9a-f-]{36}$/
// Run 1: a config agent persists a turn under a generated session id.
const ctx1 = new Context()
await ctx1.plugin(LlmService)
await ctx1.plugin(SessionStore)
await ctx1.plugin(SystemPrompt)
await ctx1.plugin(ToolRegistry)
await ctx1.plugin(AgentRegistry)
await ctx1.plugin(AgentLoop, { agents: [{ id: 'cfg', model: 'mock', systemPrompt: '' }] })
await ctx1.plugin(SessionPersistenceJsonl, { root })
ctx1.llm.registerAdapter(['mock'], new MockAdapter([textResponse('cfg')]))
const a1 = ctx1.agents.get('cfg') as LoopAgent
expect(a1.session.id).toMatch(idPattern)
a1.send([{ type: 'text', text: 'q' }], { source: { kind: 'user' } })
await waitForIdle(ctx1, a1)
await ctx1.fiber.dispose()
// Run 2 over the SAME root: a fresh id means no on-disk collision (a fixed
// ${id}-session would crash here with "already has a persisted log").
const ctx2 = new Context()
await ctx2.plugin(LlmService)
await ctx2.plugin(SessionStore)
await ctx2.plugin(SystemPrompt)
await ctx2.plugin(ToolRegistry)
await ctx2.plugin(AgentRegistry)
await ctx2.plugin(AgentLoop, { agents: [{ id: 'cfg', model: 'mock', systemPrompt: '' }] })
await ctx2.plugin(SessionPersistenceJsonl, { root })
ctx2.llm.registerAdapter(['mock'], new MockAdapter([textResponse('cfg2')]))
const a2 = ctx2.agents.get('cfg') as LoopAgent
expect(a2.session.id).toMatch(idPattern)
expect(a2.session.id).not.toBe(a1.session.id)
a2.send([{ type: 'text', text: 'q2' }], { source: { kind: 'user' } })
await waitForIdle(ctx2, a2)
await ctx2.fiber.dispose()
})
})

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@@ -0,0 +1,33 @@
# @deepseek-ai/dsh-session-persistence-jsonl
The JSONL durable session-persistence backend — a concrete `SessionPersistence` (the `dsh-session-persistence` seam). One append-only `.jsonl` event log per session plus a small atomic `.summary.json` sidecar for mutable metadata.
## On-disk layout
```
<root>/
cwd-<sha256(cwd)[:12]>/ # per-project bucket (or _no-cwd/ when no cwd)
<encoded-id>.jsonl # header line + one SessionEvent per line (verbatim)
<encoded-id>.summary.json # mutable SessionSummary (atomic temp-write + rename)
```
- The first `.jsonl` line is the immutable `SessionHeader` tagged `{ type: 'session', version, id, cwd?, createdAt, parentSession? }`; every subsequent line is one `SessionEvent` JSON, **verbatim including `assistant/chunk`** so `seq` stays contiguous (`events[i].seq === i`).
- Session ids are unvalidated branded strings, so they are percent-encoded to a single safe path segment before use (no traversal, no collision).
## Config
| Key | Type | Notes |
|---|---|---|
| `root` | `string` (required) | Root directory for all session files. **No default** — a `process.cwd()` default would scatter files as the process's cwd changes (bash calls, subprocesses). |
## Durability and crash semantics
- **Lazy materialization.** `create(meta)` writes nothing; the `.jsonl` (header + first batch) is written atomically (temp-write + `fsync` + rename) on the first `append`. A created-but-never-appended session leaves nothing on disk and is absent from `has`/`list`.
- **Append-only.** Committed events (at or below a flushed `turn/end`) are never rewritten. Subsequent appends are line appends at EOF + `fsync`.
- **Truncation-repair.** `load` returns events only up to the last complete `turn/end` and records the byte offset of any never-committed crash tail; the first post-load `append` `ftruncate`s to that offset (+ `fsync`) before writing, atomically discarding only the uncommitted tail.
- **Contiguous-seq.** `load` rejects a mid-log parse error or `seq` gap (unloadable); `append` rejects a batch whose first `seq` does not continue the stored log, and rejects non-JSON-serializable `event.data` naming the offending event type.
- **Format version.** Only v1 is supported; `load` rejects an unknown version. A future format change requires a version bump + migration.
## Write path
The plugin generalizes the example `session-jsonl.ts`: it subscribes to `session/created` (capture the header; persist a fork's seed once), `session/event` (snapshot each event when buffering — the live `session.events` object is mutable), and `session/flush`/dispose (drain the write-behind buffer through `append`). A per-session write cursor means a resumed session never re-appends already-stored events. Existing live sessions are seeded on plugin apply (HMR does not replay `session/created`). All backend operations for one session are serialized, and disposal awaits quiescence (every init + final drain) before returning, so no write lands after teardown.

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@@ -0,0 +1,35 @@
{
"name": "@deepseek-ai/dsh-session-persistence-jsonl",
"description": "JSONL durable session persistence backend for the DeepSeek Harness",
"version": "0.0.1",
"private": true,
"type": "module",
"main": "lib/index.js",
"types": "lib/index.d.ts",
"exports": {
".": {
"types": "./lib/index.d.ts",
"default": "./lib/index.js"
},
"./src/*": "./src/*",
"./package.json": "./package.json"
},
"files": [
"lib",
"src"
],
"license": "BSD-3-Clause",
"peerDependencies": {
"@deepseek-ai/dsh-session": "^0.0.1",
"@deepseek-ai/dsh-session-persistence": "^0.0.1",
"cordis": "^4.0.0-rc.6"
},
"dependencies": {
"schemastery": "^3.18.0"
},
"devDependencies": {
"@deepseek-ai/dsh-session": "^0.0.1",
"@deepseek-ai/dsh-session-persistence": "^0.0.1",
"cordis": "^4.0.0-rc.6"
}
}

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@@ -0,0 +1,249 @@
/**
* On-disk format helpers for the JSONL session-persistence backend: path
* sanitization (a {@link SessionId} is an unvalidated branded string, so it
* MUST be encoded before use in a path — no traversal, no collision), the
* per-cwd directory layout, header-line (de)serialization, the atomic sidecar
* for mutable summary fields, and the truncation-repair offset computation.
*
* @module dsh-session-persistence-jsonl/format
*/
import { createHash } from 'node:crypto'
import { join } from 'node:path'
import type { SessionEvent, SessionHeader, SessionId, SessionMeta } from '@deepseek-ai/dsh-session'
/**
* The first line of a session's `.jsonl` file: the immutable
* {@link SessionHeader} tagged as a `session` record so a reader can tell it
* apart from an event line.
*/
export interface HeaderLine {
type: 'session'
version: number
id: SessionId
createdAt: number
cwd?: string
parentSession?: SessionId
}
/** Build the header line object from a {@link SessionHeader}. */
export function toHeaderLine(header: SessionHeader): HeaderLine {
return {
type: 'session',
version: header.version,
id: header.id,
createdAt: header.createdAt,
...header.cwd !== undefined ? { cwd: header.cwd } : {},
...header.parentSession !== undefined ? { parentSession: header.parentSession } : {},
}
}
/** Parse a header line back into a {@link SessionHeader}. */
export function fromHeaderLine(line: HeaderLine): SessionHeader {
return {
version: line.version,
id: line.id,
createdAt: line.createdAt,
...line.cwd !== undefined ? { cwd: line.cwd } : {},
...line.parentSession !== undefined ? { parentSession: line.parentSession } : {},
}
}
/** Type guard: a parsed first line is a well-formed session header. */
function isHeaderLine(value: unknown): value is HeaderLine {
return (
typeof value === 'object' && value !== null
&& (value as { type?: unknown }).type === 'session'
&& typeof (value as { version?: unknown }).version === 'number'
&& typeof (value as { id?: unknown }).id === 'string'
&& typeof (value as { createdAt?: unknown }).createdAt === 'number'
)
}
/**
* Encode an arbitrary string as a single safe path segment, injectively over
* ALL JS (UTF-16) strings — including lone surrogates. A {@link SessionId} is
* an unvalidated branded string, so this neutralizes `../`, absolute paths,
* NUL, and separators before any filesystem use.
*
* Each UTF-16 code unit is either kept literal (the safe set `[A-Za-z0-9_-]`)
* or escaped as `~XXXX` (its 4-hex-digit code unit). `~` is itself escaped, so
* the mapping is injective and reversible: distinct inputs never collide. We
* iterate code UNITS (`charCodeAt`), not code points, so a lone surrogate
* escapes to a distinct `~XXXX` instead of being normalized to U+FFFD (which
* `Buffer.from(…, 'utf8')` would do, breaking injectivity). `.` is in the safe
* set for readability but the whole-segment tokens `.`/`..` are escaped so they
* can never traverse.
*/
export function encodeSegment(raw: string): string {
if (raw.length === 0) throw new Error('cannot encode an empty path segment')
if (raw === '.') return '~002E'
if (raw === '..') return '~002E~002E'
let out = ''
for (let i = 0; i < raw.length; i++) {
const code = raw.charCodeAt(i)
const ch = String.fromCharCode(code)
if (ch !== '~' && /^[A-Za-z0-9._-]$/.test(ch)) {
out += ch
} else {
out += '~' + code.toString(16).toUpperCase().padStart(4, '0')
}
}
return out
}
/**
* The directory a session's files live in: the configured root, then a per-cwd
* subdirectory so sessions group by project. The cwd subdir is a stable hash
* (short, collision-resistant, filesystem-safe) plus an encoded suffix for
* readability; sessions without a cwd go in a shared `_no-cwd` bucket.
*/
export function sessionDir(root: string, cwd: string | undefined): string {
if (cwd === undefined) return join(root, '_no-cwd')
const hash = createHash('sha256').update(cwd).digest('hex').slice(0, 12)
return join(root, `cwd-${hash}`)
}
/** The append-only event-log file path for a session. */
export function logPath(root: string, cwd: string | undefined, id: SessionId): string {
return join(sessionDir(root, cwd), `${encodeSegment(id)}.jsonl`)
}
/** The mutable-summary sidecar path for a session (beside its log). */
export function sidecarPath(root: string, cwd: string | undefined, id: SessionId): string {
return join(sessionDir(root, cwd), `${encodeSegment(id)}.summary.json`)
}
/** Serialize one event as a JSONL line (no trailing newline). */
export function eventLine(event: SessionEvent): string {
return JSON.stringify(event)
}
/**
* Compute the byte offset of the END of the last complete `turn/end` line in a
* JSONL log buffer (the header line is index 0). Returns the offset to which a
* crash tail should be truncated, and the contiguous events up to and including
* that `turn/end`. A parse error or a `seq` gap in the MIDDLE (at or before the
* last `turn/end`) makes the session unloadable and throws; trailing garbage
* AFTER the last `turn/end` is the tolerated crash tail and is excluded.
*
* This relies on the session-log invariant that every event lives inside a turn
* (`Session.append` enforces it): the last `turn/end` is therefore the last
* durable boundary, and nothing committed can sit outside a completed turn.
*/
export function scanLog(buffer: Buffer): { meta: SessionMeta; events: SessionEvent[]; committedBytes: number } {
const text = buffer.toString('utf8')
// Split into complete (newline-terminated) lines, tracking the byte offset of
// each line's end so the truncation point is exact (multi-byte chars make the
// char offset differ from the byte offset). A trailing line with no newline is
// an uncommitted crash fragment and is ignored — it is below the last
// turn/end by construction (the loop only flushes whole lines).
//
// Track the byte offset with a RUNNING accumulator (`endByte`), adding each
// line's byte length as we go. Recomputing `Buffer.byteLength(text.slice(0, i))`
// per newline would rescan the whole prefix every time — O(n²) over a long
// log (one assistant/chunk line per token makes that pathological).
const lines: { text: string; endByte: number }[] = []
let start = 0
let byteOffset = 0
for (let i = 0; i < text.length; i++) {
if (text[i] === '\n') {
const lineText = text.slice(start, i)
byteOffset += Buffer.byteLength(lineText, 'utf8') + 1 // +1 for the '\n' (a 1-byte char)
lines.push({ text: lineText, endByte: byteOffset })
start = i + 1
}
}
const [headerEntry, ...eventEntries] = lines
if (headerEntry === undefined) throw new Error('empty or header-less session log')
// Line 0 is the header.
let parsedHeader: unknown
try {
parsedHeader = JSON.parse(headerEntry.text)
} catch {
throw new Error('corrupt session log: header line is not valid JSON')
}
if (!isHeaderLine(parsedHeader)) {
throw new Error('corrupt session log: first line is not a session header')
}
const headerLine = parsedHeader
// Find the committed region: the prefix up to and including the LAST complete
// `turn/end` in the WHOLE log. Two passes so a crash tail after the last
// turn/end is tolerated, but corruption/gaps AT OR BEFORE the last committed
// turn/end make the log unloadable (committed data must never be silently
// dropped).
//
// Pass 1: parse every line that parses, recording (parsedOk, seq, isTurnEnd,
// endByte) per line index. Lines that fail to parse are holes.
interface Parsed { ok: boolean; event?: SessionEvent; endByte: number }
const parsed: Parsed[] = eventEntries.map((entry) => {
try {
return { ok: true, event: JSON.parse(entry.text) as SessionEvent, endByte: entry.endByte }
} catch {
return { ok: false, endByte: entry.endByte }
}
})
// The last index (into eventEntries) that is a valid `turn/end`.
let lastTurnEnd = -1
for (let i = parsed.length - 1; i >= 0; i--) {
const p = parsed[i]
if (p?.ok && p.event?.type === 'turn/end') { lastTurnEnd = i; break }
}
// No committed turn/end anywhere: nothing is committed. The whole event
// region is an uncommitted (first-turn) tail — committedBytes is the header.
if (lastTurnEnd < 0) {
const meta = metaFrom(headerLine)
return { meta, events: [], committedBytes: headerEntry.endByte }
}
// Pass 2: the committed prefix [0..lastTurnEnd] must be fully intact and
// contiguous (line i is a parsed event with seq === i). A hole or seq gap in
// the committed region means committed data was damaged → unloadable.
const committed: SessionEvent[] = []
for (let i = 0; i <= lastTurnEnd; i++) {
const p = parsed[i]
if (!p?.ok || p.event === undefined) {
throw new Error(`corrupt session log: unparsable committed event at line ${i + 1}`)
}
if (p.event.seq !== i) {
throw new Error(`corrupt session log: seq gap in committed region at line ${i + 1} (expected ${i}, got ${p.event.seq})`)
}
committed.push(p.event)
}
const lastEntry = parsed[lastTurnEnd]
/* v8 ignore next -- lastTurnEnd indexes a parsed entry by construction */
const committedBytes = lastEntry ? lastEntry.endByte : headerEntry.endByte
return { meta: metaFrom(headerLine), events: committed, committedBytes }
}
/** Build the load-time {@link SessionMeta} from a header line (summary overlaid later). */
function metaFrom(headerLine: HeaderLine): SessionMeta {
return {
...fromHeaderLine(headerLine),
updatedAt: headerLine.createdAt, // overlaid by the sidecar in load()
}
}
/**
* Parse just the header line of a log into load-time {@link SessionMeta}, or
* `undefined` if it is missing/not a header. Used by `list()` to read session
* metadata WITHOUT parsing the whole log: a session picker scales with the
* number of sessions, not the total size of every conversation. The summary
* sidecar is overlaid by the caller; `updatedAt` here mirrors `createdAt` until
* then (same as {@link scanLog}'s load-time meta).
*/
export function parseHeaderMeta(firstLine: string): SessionMeta | undefined {
let parsed: unknown
try {
parsed = JSON.parse(firstLine)
} catch {
return undefined
}
if (!isHeaderLine(parsed)) return undefined
return metaFrom(parsed)
}

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@@ -0,0 +1,818 @@
/**
* JSONL durable session-persistence backend (`@deepseek-ai/dsh-session-persistence-jsonl`).
*
* Two concerns in one plugin:
*
* 1. **The backend** — a concrete {@link SessionPersistence}: one append-only
* `.jsonl` event log per session (a header line then one `SessionEvent` per
* line, verbatim including `assistant/chunk` so `seq` stays contiguous) plus
* a small atomic `.summary.json` sidecar for the mutable `SessionSummary`.
* Lazy materialization (no file until the first `append`), atomic first
* write, and truncation-repair of a never-committed crash tail on the first
* `append` after a `load`.
*
* 2. **The write path** — the `session/event` → buffer → `session/flush` drain
* that generalizes the example `session-jsonl.ts`: snapshot each event when
* it is buffered (the live `session.events` object is mutable), persist
* forks once on `session/created`, maintain a per-session write cursor so a
* resumed session never re-appends already-stored events, and seed existing
* live sessions on plugin apply (HMR does not replay `session/created`).
*
* @module @deepseek-ai/dsh-session-persistence-jsonl
*/
import { Context } from 'cordis'
import z from 'schemastery'
import { open, mkdir, readFile, readdir, rename, link, rm, writeFile, truncate } from 'node:fs/promises'
import { resolve } from 'node:path'
import { randomBytes } from 'node:crypto'
import { SessionPersistence } from '@deepseek-ai/dsh-session-persistence'
import { isJsonValue } from '@deepseek-ai/dsh-session'
import type { Session, SessionEvent, SessionId, SessionMeta, SessionSummary } from '@deepseek-ai/dsh-session'
import {
encodeSegment, eventLine, logPath, parseHeaderMeta, scanLog, sessionDir, sidecarPath, toHeaderLine,
} from './format.ts'
export interface Config {
/**
* Root directory for all session files. Required (no default): a default of
* `process.cwd()` would scatter session files as the process's cwd changes
* (bash calls, subprocesses). Sessions group under per-cwd subdirectories.
*/
root: string
}
/** Per-session write state held by the backend's in-memory bookkeeping. */
interface SessionState {
meta: SessionMeta
/** The next seq the backend expects to append (the stored log length). */
cursor: number
/** Whether the `.jsonl` file has been physically materialized. */
materialized: boolean
/**
* The live Session this state was bound to via `onCreated`, if any. Used to
* detect a DIFFERENT live session reusing a tracked id (a collision): state
* created through the public `create()`/`load()` API has no owner, but state
* bound to a live session lets `onCreated` reject a second, unrelated session
* object on the same id instead of silently no-opping (which would leave the
* new session's events to be dropped against the old cursor).
*/
owner?: Session
/**
* If a load truncation-repair is pending, the byte offset to truncate the
* file to before the next append (discards the never-committed crash tail).
*/
repairTo?: number
}
/**
* Whether a live session's `seed` reproduces a persisted `prefix` exactly — the
* prefix is no longer than the seed, and each prefix event DEEP-equals the seed
* event at the same index. Used to tell a session legitimately continuing a
* persisted log (HMR re-seeing its own session, or a resume) from a different
* session that merely reuses the id: the latter would have its already-counted
* seq 0..prefix-1 events filtered out on flush and its conversation silently
* grafted onto the old log.
*
* The comparison is a full structural equality (via canonical JSON) of each
* event INCLUDING its `data` payload, not just `seq`/`type`/`time` — a session
* built from loaded events but with mutated message/tool payloads (same seq/
* type/time) must NOT be accepted, or the live history and durable log diverge.
* Both sides are JSON-serializable by contract (Session.append enforces it), so
* JSON.stringify is a sound canonical form here.
*/
function seedCoversPrefix(seed: readonly SessionEvent[], prefix: readonly SessionEvent[]): boolean {
return prefix.length <= seed.length
&& prefix.every((e, i) => {
const s = seed[i]
return s !== undefined && JSON.stringify(s) === JSON.stringify(e)
})
}
/**
* Reject non-JSON-serializable `event.data`, naming the offending type. Used on
* the backend's `append(events)` entry point (replay/fork paths that bypass a
* live `Session`); events that flow through `Session.append` are already
* validated at the source, so the live write path never needs this.
*/
function assertSerializable(events: readonly SessionEvent[]): void {
for (const event of events) {
if (!isJsonValue(event.data)) {
throw new Error(`event "${event.type}" carries non-JSON-serializable data (seq ${event.seq})`)
}
}
}
/**
* The JSONL persistence backend. Load as a plugin; it registers as
* `ctx.sessionPersistence` and installs the write-path listeners.
*/
export class SessionPersistenceJsonl extends SessionPersistence {
static inject = ['sessions']
static Config: z<Config> = z.object({
root: z.string().required(),
})
private root: string
/** Backend bookkeeping keyed by session id (NOT the live Session object). */
private states = new Map<string, SessionState>()
/** Write-behind buffers keyed by the live Session (write path). */
private buffers = new Map<Session, SessionEvent[]>()
/**
* Per-session serialization: every backend operation chains onto the prior
* one for the same id, so concurrent flushes / a flush racing onCreated never
* interleave file writes or read a half-built state. Keyed by session id.
*/
private chains = new Map<string, Promise<unknown>>()
/**
* Per-session init promise (onCreated). Keyed by the LIVE Session OBJECT, not
* its id: a disposed fiber's session can be replaced by a different live
* Session reusing the same id (HMR, an ACP reconnect), and an id-keyed cache
* would hand the new object the old object's init promise — skipping
* onCreated for the new session, so its events start at seq 0 while flush
* filters against the stale cursor and silently drops them. Keying by object
* gives each live Session its own init. flush awaits it before appending.
*/
private inits = new Map<Session, Promise<void>>()
constructor(ctx: Context, public config: Config) {
super(ctx)
// Resolve the configured root to an ABSOLUTE path ONCE, here. A relative
// root (the examples use `./.sessions`) would otherwise re-resolve against
// `process.cwd()` at every later readdir/open — so if any plugin or test
// changed cwd between create, append, and load, one session's files could
// split across directories. Pinning it at construction makes all paths
// stable regardless of later cwd changes.
this.root = resolve(config.root)
this.installWritePath()
}
// --- SessionPersistence backend surface (all serialized per session id) ---
create(meta: SessionMeta): Promise<void> {
// Snapshot the metadata at call time: the op runs later (behind the
// per-session chain) and the snapshot is also stored as the lazy state, so
// keeping the caller's object by reference would let a later mutation of
// `id`/`cwd` register under one key but materialize under a different
// path/header. A shallow copy is enough — SessionMeta is a flat record.
const snapshot: SessionMeta = { ...meta }
return this.serialize(snapshot.id, () => this.createCore(snapshot))
}
private async createCore(meta: SessionMeta): Promise<void> {
// Do NOT clobber an existing session. If we already track it, or a log
// exists on disk under this id, refuse — the SessionId IS the identity, and
// silently resetting state (cursor 0, materialized false) over committed
// data would let the next append rename over the existing log.
if (this.states.has(meta.id)) {
throw new Error(`session "${meta.id}" already exists in this backend`)
}
// Scan ALL cwd buckets (pass undefined), not just meta.cwd's: load/has/adopt
// identify a session by id alone and search every bucket, so an id already
// persisted under a DIFFERENT cwd must still block creation here. Probing
// only meta.cwd's bucket would let two logs share one id and make resume
// (which picks the first matching bucket) nondeterministic.
if (await this.findLog(meta.id, undefined) !== undefined) {
throw new Error(`session "${meta.id}" already has a persisted log on disk; load/resume it instead of creating`)
}
// Pure lazy: record intent only. No file until the first append, so an
// abandoned (never-appended) session leaves nothing on disk and stays
// absent from has()/list().
this.states.set(meta.id, { meta, cursor: 0, materialized: false })
}
/**
* Run `op` after any in-flight operation for the same session id, so writes
* for one session never interleave (two flushes, a flush racing a load, an
* update racing an append). Errors do not poison the chain — the next op
* still runs. NOTE: serialized public methods must NOT call each other (that
* would deadlock on the same chain); they call the unserialized `*Core`
* helpers instead.
*/
private serialize<T>(id: SessionId, op: () => Promise<T>): Promise<T> {
const prior = this.chains.get(id) ?? Promise.resolve()
const next = prior.then(op, op)
// Keep the chain alive but swallow this op's rejection for the NEXT waiter
// (the caller still sees the real rejection via `next`).
this.chains.set(id, next.then(() => undefined, () => undefined))
return next
}
// `async` so the synchronous validate/clone below reject (not throw) per the
// Promise<void> contract — callers use `await expect(...).rejects`.
async append(id: SessionId, events: readonly SessionEvent[]): Promise<void> {
// Validate serializability BEFORE cloning, so a bad event surfaces the typed
// "non-JSON-serializable" error rather than an opaque DataCloneError from
// structuredClone below. (In an async method this throw becomes a rejection,
// honoring the Promise<void> contract rather than throwing synchronously.)
assertSerializable(events)
// Deep-snapshot the batch here, BEFORE the op waits behind the per-session
// chain: the op may await before serializing, so a caller that passes a live
// array (e.g. session.events) and mutates it — OR mutates an event object
// inside it — before the op runs would otherwise have those changes
// persisted, or advance the cursor past what was actually written.
// structuredClone covers both the array and the event objects (safe now that
// serializability is checked above). The clone happens synchronously (before
// the first await), so it is taken at call time.
const batch = events.map(e => structuredClone(e))
return this.serialize(id, () => this.appendCore(id, batch))
}
private async appendCore(id: SessionId, events: readonly SessionEvent[]): Promise<void> {
if (events.length === 0) return
assertSerializable(events)
let state = this.states.get(id)
if (state === undefined) state = await this.adopt(id) // calls loadCore, not load
// Truncation-repair: on the first append after a load that found a crash
// tail, physically discard the orphaned bytes before writing.
if (state.repairTo !== undefined) {
await this.repair(state, state.repairTo)
delete state.repairTo
}
// Contiguity contract: each event's seq must continue the stored log.
for (const [i, event] of events.entries()) {
if (event.seq !== state.cursor + i) {
throw new Error(`append seq mismatch for "${id}": expected ${state.cursor + i} at index ${i}, got ${event.seq}`)
}
}
if (!state.materialized) {
await this.materialize(state, events)
} else {
await this.appendLines(state, events)
}
// The durable event log is the transaction: advance the cursor as soon as
// the log write commits. The sidecar (mutable summary) is best-effort here
// — a failed sidecar write must NOT reject an append whose log already
// landed (that would desync the cursor and let a retry duplicate seqs).
state.cursor += events.length
await this.touchSummary(state).catch(() => { /* sidecar is recoverable metadata; log is durable */ })
}
load(id: SessionId): Promise<{ meta: SessionMeta; events: SessionEvent[] }> {
return this.serialize(id, () => this.loadCore(id))
}
private async loadCore(id: SessionId): Promise<{ meta: SessionMeta; events: SessionEvent[] }> {
const cwd = this.states.get(id)?.meta.cwd
const file = await this.findLog(id, cwd)
if (file === undefined) throw new Error(`session "${id}" not found`)
const buffer = await readFile(file.path)
const { meta, events, committedBytes } = scanLog(buffer)
this.assertVersion(meta)
const summary = await this.readSidecar(id, meta.cwd)
const fullMeta: SessionMeta = { ...meta, ...summary }
// Record the state so the next append repairs the crash tail (if any) and
// continues at the committed length. The state keeps its OWN copy of the
// meta; the value returned to the caller is a SEPARATE copy so a consumer
// mutating `loaded.meta` (e.g. `cwd`) cannot corrupt the backend's pathing
// metadata and send later reads/writes to the wrong log.
const needsRepair = committedBytes < buffer.byteLength
this.states.set(id, {
meta: { ...fullMeta },
cursor: events.length,
materialized: true,
...needsRepair ? { repairTo: committedBytes } : {},
})
return { meta: fullMeta, events }
}
async list(): Promise<SessionMeta[]> {
const metas: SessionMeta[] = []
for (const dir of await this.listCwdDirs()) {
for (const name of await this.listJsonl(dir)) {
// Read ONLY the header line, not the whole log: a session picker must
// scale with the number of sessions, not the total size of every
// conversation (the log persists every assistant/chunk verbatim, so a
// full scanLog here would be O(total history)).
const first = await this.readFirstLine(`${dir}/${name}`)
if (first === undefined) continue // empty/half-written file
const meta = parseHeaderMeta(first)
if (meta === undefined) continue // not a session header
const summary = await this.readSidecar(meta.id, meta.cwd)
metas.push({ ...meta, ...summary })
}
}
return metas
}
/**
* Read the first newline-terminated line of a file without loading the whole
* file. Returns undefined if the file is empty or has no complete first line
* (a half-written log). Reads in bounded chunks so a huge log costs only the
* header read.
*/
private async readFirstLine(path: string): Promise<string | undefined> {
const handle = await open(path, 'r')
try {
const chunks: Buffer[] = []
const buf = Buffer.alloc(8192)
for (;;) {
const { bytesRead } = await handle.read(buf, 0, buf.length, null)
if (bytesRead === 0) return undefined // EOF with no newline → no complete line
const slice = buf.subarray(0, bytesRead)
const nl = slice.indexOf(0x0a)
if (nl !== -1) {
chunks.push(slice.subarray(0, nl))
return Buffer.concat(chunks).toString('utf8')
}
chunks.push(Buffer.from(slice))
}
} finally {
await handle.close()
}
}
async has(id: SessionId): Promise<boolean> {
const state = this.states.get(id)
if (state?.materialized) return true
const cwd = state?.meta.cwd
return (await this.findLog(id, cwd)) !== undefined
}
delete(id: SessionId): Promise<void> {
return this.serialize(id, () => this.deleteCore(id))
}
private async deleteCore(id: SessionId): Promise<void> {
const cwd = this.states.get(id)?.meta.cwd
const file = await this.findLog(id, cwd)
if (file) await rm(file.path, { force: true })
// Remove the sidecar too. A lazy session (update() before the first
// append()) has a `.summary.json` sidecar but NO `.jsonl` log, and after a
// restart the in-memory cwd is gone — so keying sidecar removal off the log
// or the in-memory cwd would leak its possibly-sensitive title/firstPrompt.
// Scan every cwd bucket for the sidecar by its (sanitized) filename.
await this.removeSidecars(id)
this.states.delete(id)
}
/** Remove a session's summary sidecar from EVERY cwd bucket (id is unique). */
private async removeSidecars(id: SessionId): Promise<void> {
const target = `${encodeSegment(id)}.summary.json`
for (const dir of await this.listCwdDirs()) {
await rm(`${dir}/${target}`, { force: true })
}
}
update(id: SessionId, summary: Partial<SessionSummary>): Promise<void> {
return this.serialize(id, () => this.updateCore(id, summary))
}
private async updateCore(id: SessionId, summary: Partial<SessionSummary>): Promise<void> {
let state = this.states.get(id)
if (state === undefined) state = await this.adopt(id)
// Build the NEXT meta separately and commit it to in-memory state only AFTER
// the sidecar write succeeds. update's only durable effect is the sidecar,
// so a failure DOES reject (unlike append, whose log is the transaction and
// sidecar is best-effort) — but if we mutated state.meta first, a later
// touchSummary() on a successful append would persist the rejected
// title/firstPrompt, making a failed update durable after the fact.
const nextMeta: SessionMeta = { ...state.meta, ...summary }
await this.writeSidecar(nextMeta)
state.meta = nextMeta
}
// --- materialization / append / repair ---
/** Atomically write the header line + first batch (temp-write, fsync, rename). */
private async materialize(state: SessionState, events: readonly SessionEvent[]): Promise<void> {
const dir = sessionDir(this.root, state.meta.cwd)
await mkdir(dir, { recursive: true, mode: 0o700 })
const finalPath = logPath(this.root, state.meta.cwd, state.meta.id)
// Never rename over an existing committed log: materialize is the FIRST
// write of a session the backend believes is new. A file here means a
// different session shares this id on disk — reject loudly rather than
// clobber committed data. (createCore already guards the create path before
// this point, so this is unreachable-in-practice defense-in-depth against a
// TOCTOU/fork race; ignored for coverage.)
/* v8 ignore next 3 -- createCore guards collisions before materialize; this is a TOCTOU backstop */
if (await this.exists(finalPath)) {
throw new Error(`refusing to materialize "${state.meta.id}": a log already exists on disk (load/resume it instead)`)
}
const header = JSON.stringify(toHeaderLine(state.meta))
const body = events.map(eventLine).join('\n')
const content = header + '\n' + body + '\n'
const tmp = `${finalPath}.${randomBytes(6).toString('hex')}.tmp`
const handle = await open(tmp, 'wx', 0o600)
try {
await handle.writeFile(content)
await handle.sync()
} finally {
await handle.close()
}
// Publish via link()+unlink(), NOT rename(): link fails with EEXIST if the
// final path already exists, so two processes materializing the same id
// concurrently cannot clobber each other (both could pass the exists() check
// above, but only one link() wins). rename() would silently overwrite the
// log the other process just committed. The temp link is always removed,
// whether link() succeeds or throws (EEXIST on a race, or any I/O error).
try {
await link(tmp, finalPath)
} finally {
await rm(tmp, { force: true })
}
// fsync the directory so the new entry survives a power loss: on POSIX
// filesystems the new link is not crash-durable until the parent directory's
// metadata is synced. The seam contract is "append returns once durable",
// and materialize is the first append's write — so the directory entry must
// be durable before we return.
await this.syncDir(dir)
state.materialized = true
}
/** fsync a directory so a just-created/renamed entry inside it is crash-durable. */
private async syncDir(dir: string): Promise<void> {
const handle = await open(dir, 'r')
try {
await handle.sync()
} finally {
await handle.close()
}
}
/**
* Append event lines at EOF and fsync. On a write/sync failure AFTER the
* kernel accepted some bytes (ENOSPC, an fsync error), truncate the file back
* to its pre-append size before rethrowing: `cursor` is unchanged, so the
* batch will be retried, and without this rollback the retry would append
* AFTER the partial bytes — producing duplicate seqs that make `scanLog` see a
* gap and render the session unloadable.
*/
private async appendLines(state: SessionState, events: readonly SessionEvent[]): Promise<void> {
const path = logPath(this.root, state.meta.cwd, state.meta.id)
const handle = await open(path, 'a')
try {
const { size: before } = await handle.stat()
try {
await handle.writeFile(events.map(eventLine).join('\n') + '\n')
await handle.sync()
} catch (error) {
// Roll back whatever bytes landed so a retry starts from a clean EOF.
await handle.truncate(before)
await handle.sync()
throw error
}
} finally {
await handle.close()
}
}
/** Truncate the log file to `offset` bytes and fsync (discard the crash tail). */
private async repair(state: SessionState, offset: number): Promise<void> {
const path = logPath(this.root, state.meta.cwd, state.meta.id)
await truncate(path, offset)
const handle = await open(path, 'r+')
try {
await handle.sync()
} finally {
await handle.close()
}
}
// --- sidecar (mutable summary) ---
private async touchSummary(state: SessionState): Promise<void> {
state.meta = { ...state.meta, updatedAt: Date.now() }
await this.writeSidecar(state.meta)
}
/**
* Atomic sidecar write (temp-write + rename), summary fields only.
*
* Deliberately NOT directory-fsynced (unlike {@link materialize}): the
* sidecar holds mutable, recoverable summary metadata (updatedAt, title,
* firstPrompt), not source-of-truth log data. The rename is atomic so a
* reader never sees a torn file, but a power loss may lose the most recent
* summary — acceptable because it is re-derivable and the durable log (the
* transaction) is independently synced. Strict crash-durability is reserved
* for the event log.
*/
private async writeSidecar(meta: SessionMeta): Promise<void> {
const dir = sessionDir(this.root, meta.cwd)
await mkdir(dir, { recursive: true, mode: 0o700 })
const path = sidecarPath(this.root, meta.cwd, meta.id)
const summary: SessionSummary = {
updatedAt: meta.updatedAt,
...meta.title !== undefined ? { title: meta.title } : {},
...meta.firstPrompt !== undefined ? { firstPrompt: meta.firstPrompt } : {},
}
const tmp = `${path}.${randomBytes(6).toString('hex')}.tmp`
await writeFile(tmp, JSON.stringify(summary), { mode: 0o600 })
await rename(tmp, path)
}
/**
* Read the mutable-summary sidecar, or `undefined` if it is absent/unreadable
* (a session that has never been `update()`d, or a failed sidecar write). The
* caller keeps the header-derived `updatedAt` (the session's createdAt) in
* that case rather than overlaying `0` — reporting an active session as
* updated at the Unix epoch would be wrong.
*/
private async readSidecar(id: SessionId, cwd: string | undefined): Promise<SessionSummary | undefined> {
try {
const raw = await readFile(sidecarPath(this.root, cwd, id), 'utf8')
return JSON.parse(raw) as SessionSummary
} catch {
return undefined
}
}
// --- discovery helpers ---
/** Find a session's log file across cwd buckets (when cwd is unknown). */
private async findLog(id: SessionId, cwd: string | undefined): Promise<{ path: string; cwd: string | undefined } | undefined> {
if (cwd !== undefined) {
const path = logPath(this.root, cwd, id)
return (await this.exists(path)) ? { path, cwd } : undefined
}
// Unknown cwd: scan buckets for a matching file name.
const target = encodeSegment(id) + '.jsonl'
for (const dir of await this.listCwdDirs()) {
const path = `${dir}/${target}`
if (await this.exists(path)) {
// Recover cwd from the header for accurate sidecar pathing.
const { meta } = scanLog(await readFile(path))
return { path, cwd: meta.cwd }
}
}
return undefined
}
/** The cwd-bucket directories under the root (absolute paths). */
private async listCwdDirs(): Promise<string[]> {
try {
const entries = await readdir(this.root, { withFileTypes: true })
return entries.filter(e => e.isDirectory()).map(e => `${this.root}/${e.name}`)
} catch {
return [] // root does not exist yet → no sessions
}
}
private async listJsonl(dir: string): Promise<string[]> {
const entries = await readdir(dir)
return entries.filter(n => n.endsWith('.jsonl'))
}
private async exists(path: string): Promise<boolean> {
try {
const handle = await open(path, 'r')
await handle.close()
return true
} catch {
return false
}
}
/** Build a state for a session discovered on disk but not yet in memory. */
private async adopt(id: SessionId): Promise<SessionState> {
// loadCore (NOT load) — adopt runs inside an already-serialized op, so
// re-entering the chain via the public load() would deadlock.
await this.loadCore(id)
const state = this.states.get(id)
/* v8 ignore next -- loadCore always sets the state for the id */
if (!state) throw new Error(`failed to adopt session "${id}"`)
return state
}
private assertVersion(meta: SessionMeta): void {
if (meta.version !== 1) {
throw new Error(`unsupported session format version ${meta.version} for "${meta.id}" (only v1 is supported)`)
}
}
// --- write path (session/event → flush drain) ---
private installWritePath(): void {
const ctx = this.ctx
// Capture the header on creation; persist a fork's seed once. Record the
// init promise so flush/dispose can await it (onCreated is async).
ctx.on('session/created', (session) => { void this.initFor(session) })
// Snapshot + buffer every event (the live object is mutable; clone so a
// later in-place mutation of session.events cannot rewrite a buffered
// event). Serializability is guaranteed at the source — `Session.append`
// rejects non-JSON-serializable data before the event ever enters the log
// or this emit — so structuredClone here can never hit a non-cloneable
// value, and the durable log can never diverge from session.events.
ctx.on('session/event', (session, event) => {
let buffer = this.buffers.get(session)
if (!buffer) this.buffers.set(session, buffer = [])
buffer.push(structuredClone(event))
})
// Drain to the backend at the durability checkpoint.
ctx.on('session/flush', session => this.flush(session))
// Dispose must reach quiescence: await every session's init + final drain
// BEFORE returning, so no write lands after teardown (orphan rename/ENOENT).
ctx.effect(() => async () => {
await Promise.allSettled([...this.inits.values()])
await Promise.allSettled([...this.buffers.keys()].map(s => this.flush(s)))
await Promise.allSettled([...this.chains.values()])
}, 'session-persistence-jsonl write path')
// HMR: a hot reload does not replay session/created, so seed existing live
// sessions (mirrors dsh-invariants).
for (const session of ctx.sessions.list()) void this.initFor(session)
}
/** Start (once) the async init for a session and remember its promise. */
private initFor(session: Session): Promise<void> {
const existing = this.inits.get(session)
if (existing) return existing
// Snapshot the seed SYNCHRONOUSLY here — initFor runs inside the
// `session/created` emit, before any later `append` adds non-seed events.
// A clone freezes it against later mutation of the live event objects.
const seed = session.events.map(e => structuredClone(e))
const p = this.onCreated(session, seed)
// Attach a no-op rejection handler so a failing init (e.g. an id collision)
// does not surface as an unhandled rejection if no flush observes `p` before
// it rejects. The REAL error is still delivered: flush/dispose await the
// same `p` from the map and see the rejection there.
p.catch(() => { /* observed by flush/dispose via the stored promise */ })
this.inits.set(session, p)
return p
}
/**
* Whether a live `session`'s `seed` reproduces the first `cursor` persisted
* events. Reads the on-disk committed prefix and compares. A `cursor` of 0
* (nothing persisted yet) trivially matches. Used when a live session claims
* ownerless state left by a prior `load()`/`create()` — to reject a fresh,
* unrelated session that reuses the id and would otherwise have its seq
* 0..cursor-1 events filtered as already-written.
*/
private async seedMatchesPersisted(session: Session, seed: readonly SessionEvent[], cursor: number): Promise<boolean> {
if (cursor === 0) return true
const onDisk = await this.findLog(session.header.id, session.header.cwd)
/* v8 ignore next -- a cursor > 0 means the log was materialized, so it exists */
if (onDisk === undefined) return false
const { events: diskEvents } = scanLog(await readFile(onDisk.path))
return seedCoversPrefix(seed, diskEvents.slice(0, cursor))
}
/**
* On session/created: sync the backend's in-memory state to a live Session.
*
* Cases, by whether this backend tracks the id and whether a log is on disk:
* 1. Already in `states` (created here, or a prior load/resume) → no-op.
* 2. Not tracked, a log EXISTS on disk, and it is a seq-aligned PREFIX of the
* live session's current events → ADOPT it (HMR/reload): a fresh backend
* instance (empty `states`) meets a live session whose log a previous
* instance materialized; the live object already carries that history (it
* is the source of truth this run), so we continue from the stored length
* instead of re-creating. This keeps persistence alive across hot reload.
* 3. Not tracked, a log EXISTS on disk, but it is NOT a prefix of the live
* session's events → REJECT: a different session collides on the id. The
* SessionId is the identity, so two unrelated sessions sharing one is a
* bug, not a resume — fail loudly rather than clobber committed data.
* 4. Not tracked and NO log on disk → a genuinely new session: register its
* meta (lazy) and persist its `seed` once.
*
* The public `create(meta)` API is stricter still (rejects ANY on-disk id):
* there the caller asserts "brand new", so even a prefix match is a bug.
*
* The seed events were copied into the Session by its constructor WITHOUT
* emitting session/event, so the write-behind buffer never sees them — the
* one explicit `append(seed)` below is the only persistence of the seed.
* Events appended AFTER creation flow through the session/event buffer and
* are persisted by flush (filtered by the write cursor), never here.
*/
private async onCreated(session: Session, seed: readonly SessionEvent[]): Promise<void> {
const id = session.header.id
const tracked = this.states.get(id)
if (tracked !== undefined) {
// case 1: already tracked.
// (owner === session is a defensive same-object guard: initFor dedupes by
// session object, so onCreated never actually runs twice for one session.)
/* v8 ignore next -- initFor dedupes per session object; same-object re-entry can't occur */
if (tracked.owner === session) return
if (tracked.owner === undefined) {
// Ownerless state was created via the public create()/load() API. The
// FIRST live session to arrive claims it — but ONLY if its seed is the
// already-persisted prefix. A load() for preview leaves cursor at the
// persisted length; a fresh, unrelated session reusing that id has a
// seed shorter than (or not matching) that prefix, so flush would filter
// its seq 0..cursor-1 events as already-written and silently graft the
// new conversation onto the old log. Verify the seed covers the cursor.
if (!await this.seedMatchesPersisted(session, seed, tracked.cursor)) {
throw new Error(`session "${id}" is already persisted with ${tracked.cursor} event(s) that do not match this live session (id collision)`)
}
tracked.owner = session
// Persist the live seed SUFFIX beyond the persisted prefix. Constructor
// seed events (from sessions.create(id, { seed })) never emit
// session/event, so the write-behind buffer never sees them — without
// this they would be lost and a later flush would seq-mismatch. (cursor
// is 0 for a public create(), so this covers the whole seed there.)
const suffix = seed.slice(tracked.cursor)
if (suffix.length > 0) await this.append(id, suffix)
return
}
// The state is owned by a DIFFERENT live session. We may reclaim the id
// ONLY if that owner left nothing behind: never materialized a log (cursor
// 0, not materialized) AND has no write-behind buffer still pending. A
// session that appended events but was disposed before its first flush is
// NOT materialized yet but DOES have buffered events — reclaiming then
// would let that stale buffer drain against the new session's state
// (persisting old events under the new id, or dropping the new session's
// seq-0 events). Such an owner, and any materialized owner, is a real
// collision and rejects; only a truly-abandoned (artifact-free) id is
// freed, honoring lazy materialization's "leaves nothing behind" promise.
const ownerBuffer = this.buffers.get(tracked.owner)
if (!tracked.materialized && !ownerBuffer?.length) {
this.states.delete(id)
} else {
throw new Error(`session "${id}" is already bound to a different live session in this backend (id collision)`)
}
}
const onDisk = await this.findLog(id, session.header.cwd)
if (onDisk !== undefined) {
// Read the committed on-disk events and check they are a seq-aligned
// prefix of the live session (HMR re-seeing its own session) vs. an
// unrelated session colliding on the id.
const { events: diskEvents } = scanLog(await readFile(onDisk.path))
if (!seedCoversPrefix(seed, diskEvents)) {
// case 3: genuine collision — fail loudly rather than clobber.
throw new Error(`session "${id}" already has a persisted log on disk that does not match this live session (id collision)`)
}
// case 2: adopt. loadCore sets the state (cursor = committed length,
// repair offset if a crash tail exists).
await this.serialize(id, () => this.loadCore(id))
const adopted = this.states.get(id)
/* v8 ignore next -- loadCore always sets the state for the id */
if (adopted !== undefined) adopted.owner = session
// Persist the live SUFFIX beyond the on-disk prefix. These events live
// ONLY in `seed` (the live session was ahead of disk — mid-turn at
// reload, or events appended while the previous backend was disposed);
// this backend never buffered them via session/event, so without this
// they would be lost and the next flush (starting at a later seq) would
// mismatch or skip them.
const suffix = seed.slice(diskEvents.length)
if (suffix.length > 0) await this.append(id, suffix)
return
}
// case 4: a genuinely new session. Register its meta (lazy), then persist
// its seed (events present at creation time) once.
const meta: SessionMeta = { ...session.header, updatedAt: Date.now() }
await this.create(meta)
// Bind this state to the live session so a later DIFFERENT session reusing
// the id is detected as a collision (case 1) rather than silently no-opped.
const created = this.states.get(id)
/* v8 ignore next -- create() always sets the state for the id */
if (created !== undefined) created.owner = session
if (seed.length > 0) {
await this.append(id, seed)
}
}
private async flush(session: Session): Promise<void> {
// Wait for the session's init (onCreated) to finish so the state/cursor and
// any fork-seed persistence are in place before we drain. Awaiting the same
// promise initFor stored also surfaces an init failure (e.g. an id
// collision) here, where the caller of session/flush observes it.
await this.inits.get(session)
// Serialize the WHOLE drain (read cursor → append → splice) on the
// per-session chain. Two concurrent flushes (e.g. an idle inject()'s
// fire-and-forget flush racing an explicit checkpoint) would otherwise both
// read the same cursor, both compute the same `fresh` slice, and the second
// append would seq-mismatch against the cursor the first already advanced.
await this.serialize(session.header.id, () => this.drain(session))
}
/** Drain a session's write buffer to disk. Caller serializes this per id. */
private async drain(session: Session): Promise<void> {
const buffer = this.buffers.get(session)
if (!buffer?.length) return
// Copy WITHOUT removing: the buffer is the only durable-pending copy of
// these events (session/event does not re-emit). Splicing before the append
// means a failed append (disk error, or a seq mismatch after a dropped bad
// event) permanently loses a completed turn. Drain the buffer only AFTER
// the append commits; events pushed during the await sit past batch.length
// and survive the prefix splice, so a retry/dispose re-drains the rest.
const batch = buffer.slice()
const state = this.states.get(session.header.id)
// Only append events at or beyond the write cursor (a resumed session's
// seed is already on disk; the cursor was set to the loaded length). flush
// awaits the init above, which always sets state, so the `?? 0` fallback is
// a defensive guard that never fires in practice.
/* v8 ignore next -- state is always set by the awaited init before flush */
const cursor = state?.cursor ?? 0
const fresh = batch.filter(e => e.seq >= cursor)
// appendCore (NOT the serialized append) — drain already runs inside the
// per-session chain, so re-entering it via append() would deadlock.
if (fresh.length > 0) await this.appendCore(session.header.id, fresh)
buffer.splice(0, batch.length)
}
}
export default SessionPersistenceJsonl

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{
"extends": "../../tsconfig.base.json",
"compilerOptions": {
"rootDir": "src",
"outDir": "lib"
},
"include": ["src"],
"references": [
{ "path": "../../vendor/cosmokit" },
{ "path": "../../vendor/cordis" },
{ "path": "../../vendor/schemastery" },
{ "path": "../session" },
{ "path": "../session-persistence" }
]
}

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# @deepseek-ai/dsh-session-persistence
The abstract durable session-persistence seam (`ctx.sessionPersistence`). Defines WHAT a persistence backend does — durably store, reload, list, and update sessions — without saying HOW. Mirrors the `dsh-bash` capability-seam template ([ADR 0009](../../docs/adr/0009-capability-seams.md)): an abstract service here, a concrete implementation in a sibling package, consumers that inject the interface.
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) travels separately as `SessionMeta`, owned by `dsh-session` and re-exported here.
## Service API (`ctx.sessionPersistence`)
| Method | Contract |
|---|---|
| `create(meta): Promise<void>` | Register a new session's metadata. MAY defer the physical write until the first `append` (lazy materialization). |
| `append(id, events): Promise<void>` | Durably persist a batch (from the `session/flush` drain). Append-only; first event `seq` == stored next-seq after any repair; rejects non-JSON-serializable data naming the offending type. |
| `load(id): Promise<{ meta; events }>` | Reload meta + log up to the last complete `turn/end`; events contiguous (`events[i].seq === i`); rejects a mid-log gap/parse error or unknown `version`. |
| `list(): Promise<SessionMeta[]>` | Lightweight listing from metadata, no full-log parse. |
| `has(id)` / `delete(id)` | Existence / removal. A zero-event lazily-materialized session is absent from `has`/`list`. |
| `update(id, summary): Promise<void>` | Update mutable `SessionSummary` fields without touching the append-only log. |
## Invariants every backend must honor
- **Append-only.** Committed events (at or below a flushed `turn/end`) are never rewritten. The only exception is the one-time truncation-repair of a never-committed crash tail on the first `append` after a `load`.
- **Contiguous seq.** `load` rejects a `seq` gap/parse error in the MIDDLE of the log; `append`'s first `seq` must equal the stored next-seq.
- **JSON-serializable data.** `append` rejects non-serializable `event.data`; backends snapshot each event when buffering (the live `session.events` object is mutable).
- **Durability.** `append` returns only once the batch is durable.
## Testing backends
Import `runPersistenceContract` from `tests/contract.ts` and call it with a factory that yields a fresh, empty backend plus a teardown. Every backend is held to the same append-only / contiguous-seq / lazy-materialization / serializability semantics; a backend's own spec adds implementation-specific tests (crash repair, path sanitization) on top.
> **TODO (validate the abstraction with a second backend):** `dsh-session-persistence-jsonl` is currently the only implementation, so the interface and `runPersistenceContract` are only proven against one storage model. A second backend — a SQLite implementation (`dsh-session-persistence-sqlite`), where each `SessionEvent` maps 1:1 onto a row `(session_id, seq, type, time, data)` — would run the SAME `runPersistenceContract` suite and so prove the seam is genuinely backend-agnostic (lazy materialization, crash-tail-on-load, contiguous-seq all expressed against a transactional store rather than an append-only file).
## Metadata types
Re-exported from `dsh-session`: `SessionHeader` (immutable: `version`, `id`, `createdAt`, `cwd?`, `parentSession?`), `SessionSummary` (mutable: `updatedAt`, `title?`, `firstPrompt?`), `SessionMeta` (their intersection).

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{
"name": "@deepseek-ai/dsh-session-persistence",
"description": "Abstract durable session persistence seam (ctx.sessionPersistence) for the DeepSeek Harness",
"version": "0.0.1",
"private": true,
"type": "module",
"main": "lib/index.js",
"types": "lib/index.d.ts",
"exports": {
".": {
"types": "./lib/index.d.ts",
"default": "./lib/index.js"
},
"./src/*": "./src/*",
"./package.json": "./package.json"
},
"files": [
"lib",
"src"
],
"license": "BSD-3-Clause",
"peerDependencies": {
"@deepseek-ai/dsh-session": "^0.0.1",
"cordis": "^4.0.0-rc.6"
},
"devDependencies": {
"@deepseek-ai/dsh-session": "^0.0.1",
"cordis": "^4.0.0-rc.6"
}
}

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/**
* The durable session-persistence seam (`ctx.sessionPersistence`): an abstract
* service defining WHAT a persistence backend does — durably store, reload,
* list, and update sessions — without saying HOW. Implementations subclass
* {@link SessionPersistence} and register themselves as the
* `sessionPersistence` service; `@deepseek-ai/dsh-session-persistence-jsonl`
* (an append-only JSONL log per session) is the first. Future backends swap in
* SQLite/WAL, an object store, or a remote service without touching the
* consumers (the write-path plugin, the agent-loop resume seam).
*
* The persisted unit IS the existing {@link SessionEvent} — there is no
* parallel "persisted message" type the log must be converted to and from
* (faithful to the event-sourced model: the log is the single source of
* truth). Metadata that is NOT replayable conversation state (format version,
* cwd, lineage) travels separately as {@link SessionMeta}, which is owned by
* `dsh-session` and re-exported here.
*
* @module @deepseek-ai/dsh-session-persistence
*/
import { Context, Service } from 'cordis'
import type { SessionEvent, SessionId, SessionMeta, SessionSummary } from '@deepseek-ai/dsh-session'
// Re-export the metadata vocabulary so consumers import it from the seam.
export type { SessionHeader, SessionSummary, SessionMeta } from '@deepseek-ai/dsh-session'
declare module 'cordis' {
interface Context {
sessionPersistence: SessionPersistence
}
}
/**
* Abstract durable session-persistence service. Subclass, implement the
* abstract methods, and load the subclass as a plugin — it registers as
* `ctx.sessionPersistence` (one implementation per context; loading a second
* throws, cordis' standard duplicate-service behavior).
*
* Contracts every implementation MUST honor (a DB backend asserts them inside
* a transaction; a file backend appends at EOF):
*
* - **Append-only.** Committed events — those at or below a flushed `turn/end`
* — are never rewritten. The ONLY exception is the one-time truncation-repair
* of a never-committed crash tail on the first {@link append} after a
* {@link load} (see {@link load}).
* - **Contiguous seq.** A persisted log is contiguous: `events[i].seq === i`.
* {@link load} rejects a parse error or a `seq` gap in the MIDDLE of the log
* (unloadable); {@link append}'s first event `seq` MUST equal the backend's
* stored next-seq after any repair.
* - **JSON-serializable data.** `SessionEventMap` is merge-extensible and
* `event.data` is typed only as `SessionEventMap[K]`, so {@link append}
* REJECTS non-JSON-serializable data with an error naming the offending
* event type. A backend snapshots (serializes/clones) each event when it
* buffers, since `session.events` hands out the live mutable object.
* - **Durability.** {@link append} returns only once the batch is durable
* (the file backend fsyncs; a DB commits). {@link create} MAY defer the
* physical write until the first {@link append} (lazy materialization).
*/
export abstract class SessionPersistence extends Service {
constructor(ctx: Context) {
super(ctx, 'sessionPersistence')
}
/**
* Register a new session's metadata. A backend MAY defer the physical write
* until the first {@link append} (lazy materialization), in which case a
* created-but-never-appended session is absent from {@link has}/{@link list}
* — abandoned sessions leave nothing behind.
*/
abstract create(meta: SessionMeta): Promise<void>
/**
* Durably persist a batch of events (called from the write-behind drain at
* the `session/flush` checkpoint). Honors the append-only and contiguous-seq
* contracts: the first event's `seq` MUST equal the stored next-seq after
* any truncation-repair of a crash tail. Rejects non-JSON-serializable
* `event.data` with an error naming the offending event type.
*/
abstract append(id: SessionId, events: readonly SessionEvent[]): Promise<void>
/**
* Reload a session: its {@link SessionMeta} plus the event log up to the last
* durable checkpoint. Returns `meta` AND `events` so the live session is
* reconstructed with its `cwd`/lineage, not just its log.
*
* The loop only flushes at `turn/end`, so a crash can leave a half-written
* final turn below the last committed checkpoint. `load` returns events only
* up to the **last complete `turn/end`**; a subsequent {@link append} runs
* the one-time truncation-repair that physically discards the orphaned tail
* before writing. Returned events are contiguous (`events[i].seq === i`); a
* parse error or a `seq` gap in the MIDDLE of the log makes the session
* unloadable (reject). Rejects an unknown format `version`.
*/
abstract load(id: SessionId): Promise<{ meta: SessionMeta; events: SessionEvent[] }>
/** Lightweight listing from metadata, without a full-log parse. */
abstract list(): Promise<SessionMeta[]>
/** Whether a session is durably present (materialized). */
abstract has(id: SessionId): Promise<boolean>
/** Remove a session and all its persisted artifacts. */
abstract delete(id: SessionId): Promise<void>
/**
* Update mutable metadata ({@link SessionSummary}: `updatedAt`, `title`,
* `firstPrompt`) WITHOUT touching the append-only event log. A backend
* stores the summary beside the log (a sidecar file, a header row) and
* rewrites only it.
*/
abstract update(id: SessionId, summary: Partial<SessionSummary>): Promise<void>
}
export default SessionPersistence

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/**
* Reusable contract test for any {@link SessionPersistence} backend. A backend
* package imports {@link runPersistenceContract} and calls it with a factory
* that yields a fresh, empty backend (and a teardown), so every backend is held
* to the same append-only / contiguous-seq / lazy-materialization / crash
* semantics. The JSONL backend's own spec adds file-specific tests on top.
*
* @module @deepseek-ai/dsh-session-persistence/tests/contract
*/
import { describe, expect, it } from 'vitest'
import { SessionId } from '@deepseek-ai/dsh-session'
import type { SessionEvent, SessionMeta } from '@deepseek-ai/dsh-session'
import type { SessionPersistence } from '../src/index.ts'
/** A backend under test plus its teardown. */
export interface ContractBackend {
persistence: SessionPersistence
dispose: () => Promise<void>
}
/** Build a minimal {@link SessionMeta} for a session id. */
export function meta(id: string, cwd?: string): SessionMeta {
return {
version: 1,
id: SessionId(id),
createdAt: 1000,
updatedAt: 1000,
...cwd !== undefined ? { cwd } : {},
}
}
/** A well-formed one-turn event log (contiguous seqs from 0). */
export function oneTurnLog(): SessionEvent[] {
return [
{ type: 'turn/start', seq: 0, time: 1, data: { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } } },
{ type: 'user/message', seq: 1, time: 2, data: { content: [{ type: 'text', text: 'hi' }], source: { kind: 'user' } } },
{ type: 'step/start', seq: 2, time: 3, data: { turn: 1, step: 1 } },
{ type: 'assistant/message', seq: 3, time: 4, data: { turn: 1, step: 1, content: [{ type: 'text', text: 'hello' }] } },
{ type: 'step/end', seq: 4, time: 5, data: { turn: 1, step: 1 } },
{ type: 'turn/end', seq: 5, time: 6, data: { turn: 1, reason: { kind: 'completed' } } },
]
}
/**
* Run the backend-agnostic contract suite. `make()` MUST return a fresh, empty
* backend each call.
*/
export function runPersistenceContract(name: string, make: () => Promise<ContractBackend>): void {
describe(`SessionPersistence contract: ${name}`, () => {
it('round-trips a session: create + append → load returns identical meta and byte-identical events', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s1', '/work')
const log = oneTurnLog()
await persistence.create(m)
await persistence.append(m.id, log)
const loaded = await persistence.load(m.id)
expect(loaded.meta).toMatchObject({ version: 1, id: m.id, cwd: '/work' })
expect(loaded.events).toEqual(log)
} finally {
await dispose()
}
})
it('has()/list() exclude a created-but-never-appended (zero-event) session', async () => {
const { persistence, dispose } = await make()
try {
await persistence.create(meta('empty'))
expect(await persistence.has(SessionId('empty'))).toBe(false)
expect((await persistence.list()).map(m => m.id)).not.toContain(SessionId('empty'))
} finally {
await dispose()
}
})
it('has()/list() include a session once it has events', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s2')
await persistence.create(m)
await persistence.append(m.id, oneTurnLog())
expect(await persistence.has(m.id)).toBe(true)
expect((await persistence.list()).map(x => x.id)).toContain(m.id)
} finally {
await dispose()
}
})
it('append rejects a batch whose first seq does not match the stored next-seq', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s3')
await persistence.create(m)
await persistence.append(m.id, oneTurnLog()) // seqs 0..5, next-seq = 6
// A re-append of an already-stored seq must be rejected, not duplicated.
const restated = oneTurnLog()
await expect(persistence.append(m.id, restated)).rejects.toThrow()
} finally {
await dispose()
}
})
it('append rejects a mid-batch seq gap', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s4')
await persistence.create(m)
const gapped: SessionEvent[] = [
{ type: 'turn/start', seq: 0, time: 1, data: { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } } },
{ type: 'step/start', seq: 2, time: 2, data: { turn: 1, step: 1 } }, // gap: missing seq 1
]
await expect(persistence.append(m.id, gapped)).rejects.toThrow()
} finally {
await dispose()
}
})
it('append rejects non-JSON-serializable event data, naming the event type', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s5')
await persistence.create(m)
// A plugin-added event carrying a BigInt (not JSON-serializable).
const bad = [
{ type: 'user/message', seq: 0, time: 1, data: { content: [{ type: 'text', text: 'x' }], source: { kind: 'user' }, extra: 1n } },
] as unknown as SessionEvent[]
await expect(persistence.append(m.id, bad)).rejects.toThrow(/user\/message/)
} finally {
await dispose()
}
})
it('delete removes a session', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s6')
await persistence.create(m)
await persistence.append(m.id, oneTurnLog())
expect(await persistence.has(m.id)).toBe(true)
await persistence.delete(m.id)
expect(await persistence.has(m.id)).toBe(false)
} finally {
await dispose()
}
})
it('update mutates summary fields without touching the event log', async () => {
const { persistence, dispose } = await make()
try {
const m = meta('s7')
const log = oneTurnLog()
await persistence.create(m)
await persistence.append(m.id, log)
await persistence.update(m.id, { title: 'My session', firstPrompt: 'hi' })
const loaded = await persistence.load(m.id)
expect(loaded.meta.title).toBe('My session')
expect(loaded.meta.firstPrompt).toBe('hi')
expect(loaded.events).toEqual(log) // log untouched
} finally {
await dispose()
}
})
})
}

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import { describe, expect, it } from 'vitest'
import { Context } from 'cordis'
import { SessionId } from '@deepseek-ai/dsh-session'
import type { SessionEvent, SessionMeta, SessionSummary } from '@deepseek-ai/dsh-session'
import { SessionPersistence } from '../src/index.ts'
import { runPersistenceContract, meta, oneTurnLog } from './contract.ts'
/**
* A minimal in-memory {@link SessionPersistence} used to (a) cover the abstract
* base's constructor + service registration and (b) validate the reusable
* contract suite itself. The real durable backend is
* `@deepseek-ai/dsh-session-persistence-jsonl`.
*/
class MemoryPersistence extends SessionPersistence {
private store = new Map<string, { meta: SessionMeta; events: SessionEvent[] }>()
private pending = new Map<string, SessionMeta>()
async create(m: SessionMeta): Promise<void> {
// Lazy: record the intended meta, but stay absent from has/list until the
// first append materializes the session.
this.pending.set(m.id, m)
}
async append(id: SessionId, events: readonly SessionEvent[]): Promise<void> {
const existing = this.store.get(id)
const nextSeq = existing ? existing.events.length : 0
if (events.length > 0 && events[0]!.seq !== nextSeq) {
throw new Error(`append seq mismatch for "${id}": expected ${nextSeq}, got ${events[0]!.seq}`)
}
for (let i = 0; i < events.length; i++) {
const e = events[i]!
if (e.seq !== nextSeq + i) throw new Error(`non-contiguous seq in batch for "${id}" at index ${i}`)
if (containsNonSerializable(e.data)) {
throw new Error(`event "${e.type}" carries non-JSON-serializable data`)
}
}
if (!existing) {
const m = this.pending.get(id)
if (!m) throw new Error(`append before create for "${id}"`)
this.store.set(id, { meta: m, events: structuredClone(events) as SessionEvent[] })
} else {
existing.events.push(...structuredClone(events) as SessionEvent[])
}
}
async load(id: SessionId): Promise<{ meta: SessionMeta; events: SessionEvent[] }> {
const entry = this.store.get(id)
if (!entry) throw new Error(`session "${id}" not found`)
return { meta: structuredClone(entry.meta), events: structuredClone(entry.events) }
}
async list(): Promise<SessionMeta[]> {
return [...this.store.values()].map(e => structuredClone(e.meta))
}
async has(id: SessionId): Promise<boolean> {
return this.store.has(id)
}
async delete(id: SessionId): Promise<void> {
this.store.delete(id)
this.pending.delete(id)
}
async update(id: SessionId, summary: Partial<SessionSummary>): Promise<void> {
const entry = this.store.get(id)
if (entry) Object.assign(entry.meta, summary)
}
}
/** Detect BigInt (and other JSON-hostile values) in event data. */
function containsNonSerializable(value: unknown): boolean {
if (typeof value === 'bigint' || typeof value === 'function' || typeof value === 'symbol') return true
if (value && typeof value === 'object') {
return Object.values(value).some(containsNonSerializable)
}
return false
}
// Run the shared contract against the in-memory backend.
runPersistenceContract('memory', async () => {
const ctx = new Context()
const fiber = await ctx.plugin(MemoryPersistence)
return {
persistence: ctx.sessionPersistence,
dispose: async () => { await fiber.dispose() },
}
})
describe('SessionPersistence service registration', () => {
it('registers as ctx.sessionPersistence and is removed on fiber dispose (HMR safety)', async () => {
const ctx = new Context()
const fiber = await ctx.plugin(MemoryPersistence)
expect(ctx.sessionPersistence).toBeInstanceOf(SessionPersistence)
await fiber.dispose()
expect(ctx.sessionPersistence).toBeUndefined()
})
it('round-trips through the registered service instance', async () => {
const ctx = new Context()
const fiber = await ctx.plugin(MemoryPersistence)
const m = meta('reg')
await ctx.sessionPersistence.create(m)
await ctx.sessionPersistence.append(m.id, oneTurnLog())
const loaded = await ctx.sessionPersistence.load(m.id)
expect(loaded.events).toHaveLength(6)
await fiber.dispose()
})
})

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@@ -0,0 +1,13 @@
{
"extends": "../../tsconfig.base.json",
"compilerOptions": {
"rootDir": "src",
"outDir": "lib"
},
"include": ["src"],
"references": [
{ "path": "../../vendor/cosmokit" },
{ "path": "../../vendor/cordis" },
{ "path": "../session" }
]
}

View File

@@ -6,6 +6,8 @@ import { resolve } from 'node:path'
const packages = [ const packages = [
'packages/llm', 'packages/llm',
'packages/session', 'packages/session',
'packages/session-persistence',
'packages/session-persistence-jsonl',
'packages/system-prompt', 'packages/system-prompt',
'packages/tools', 'packages/tools',
'packages/agent', 'packages/agent',

View File

@@ -36,6 +36,8 @@
"@cordisjs/plugin-logger-console": ["./vendor/logger-console/src"], "@cordisjs/plugin-logger-console": ["./vendor/logger-console/src"],
"@deepseek-ai/dsh-llm": ["./packages/llm/src"], "@deepseek-ai/dsh-llm": ["./packages/llm/src"],
"@deepseek-ai/dsh-session": ["./packages/session/src"], "@deepseek-ai/dsh-session": ["./packages/session/src"],
"@deepseek-ai/dsh-session-persistence": ["./packages/session-persistence/src"],
"@deepseek-ai/dsh-session-persistence-jsonl": ["./packages/session-persistence-jsonl/src"],
"@deepseek-ai/dsh-system-prompt": ["./packages/system-prompt/src"], "@deepseek-ai/dsh-system-prompt": ["./packages/system-prompt/src"],
"@deepseek-ai/dsh-tools": ["./packages/tools/src"], "@deepseek-ai/dsh-tools": ["./packages/tools/src"],
"@deepseek-ai/dsh-agent": ["./packages/agent/src"], "@deepseek-ai/dsh-agent": ["./packages/agent/src"],

View File

@@ -12,6 +12,8 @@
{ "path": "./vendor/logger-console" }, { "path": "./vendor/logger-console" },
{ "path": "./packages/llm" }, { "path": "./packages/llm" },
{ "path": "./packages/session" }, { "path": "./packages/session" },
{ "path": "./packages/session-persistence" },
{ "path": "./packages/session-persistence-jsonl" },
{ "path": "./packages/system-prompt" }, { "path": "./packages/system-prompt" },
{ "path": "./packages/agent" }, { "path": "./packages/agent" },
{ "path": "./packages/tools" }, { "path": "./packages/tools" },

View File

@@ -18,6 +18,8 @@
"@cordisjs/plugin-logger-console": ["./vendor/logger-console/lib/shared"], "@cordisjs/plugin-logger-console": ["./vendor/logger-console/lib/shared"],
"@deepseek-ai/dsh-llm": ["./packages/llm/src"], "@deepseek-ai/dsh-llm": ["./packages/llm/src"],
"@deepseek-ai/dsh-session": ["./packages/session/src"], "@deepseek-ai/dsh-session": ["./packages/session/src"],
"@deepseek-ai/dsh-session-persistence": ["./packages/session-persistence/src"],
"@deepseek-ai/dsh-session-persistence-jsonl": ["./packages/session-persistence-jsonl/src"],
"@deepseek-ai/dsh-system-prompt": ["./packages/system-prompt/src"], "@deepseek-ai/dsh-system-prompt": ["./packages/system-prompt/src"],
"@deepseek-ai/dsh-tools": ["./packages/tools/src"], "@deepseek-ai/dsh-tools": ["./packages/tools/src"],
"@deepseek-ai/dsh-agent": ["./packages/agent/src"], "@deepseek-ai/dsh-agent": ["./packages/agent/src"],

View File

@@ -561,6 +561,7 @@ __metadata:
"@deepseek-ai/dsh-invariants": "npm:^0.0.1" "@deepseek-ai/dsh-invariants": "npm:^0.0.1"
"@deepseek-ai/dsh-llm": "npm:^0.0.1" "@deepseek-ai/dsh-llm": "npm:^0.0.1"
"@deepseek-ai/dsh-session": "npm:^0.0.1" "@deepseek-ai/dsh-session": "npm:^0.0.1"
"@deepseek-ai/dsh-session-persistence-jsonl": "npm:^0.0.1"
"@deepseek-ai/dsh-system-prompt": "npm:^0.0.1" "@deepseek-ai/dsh-system-prompt": "npm:^0.0.1"
"@deepseek-ai/dsh-tools": "npm:^0.0.1" "@deepseek-ai/dsh-tools": "npm:^0.0.1"
cordis: "npm:^4.0.0-rc.6" cordis: "npm:^4.0.0-rc.6"
@@ -688,6 +689,33 @@ __metadata:
languageName: unknown languageName: unknown
linkType: soft linkType: soft
"@deepseek-ai/dsh-session-persistence-jsonl@npm:^0.0.1, @deepseek-ai/dsh-session-persistence-jsonl@workspace:packages/session-persistence-jsonl":
version: 0.0.0-use.local
resolution: "@deepseek-ai/dsh-session-persistence-jsonl@workspace:packages/session-persistence-jsonl"
dependencies:
"@deepseek-ai/dsh-session": "npm:^0.0.1"
"@deepseek-ai/dsh-session-persistence": "npm:^0.0.1"
cordis: "npm:^4.0.0-rc.6"
schemastery: "npm:^3.18.0"
peerDependencies:
"@deepseek-ai/dsh-session": ^0.0.1
"@deepseek-ai/dsh-session-persistence": ^0.0.1
cordis: ^4.0.0-rc.6
languageName: unknown
linkType: soft
"@deepseek-ai/dsh-session-persistence@npm:^0.0.1, @deepseek-ai/dsh-session-persistence@workspace:packages/session-persistence":
version: 0.0.0-use.local
resolution: "@deepseek-ai/dsh-session-persistence@workspace:packages/session-persistence"
dependencies:
"@deepseek-ai/dsh-session": "npm:^0.0.1"
cordis: "npm:^4.0.0-rc.6"
peerDependencies:
"@deepseek-ai/dsh-session": ^0.0.1
cordis: ^4.0.0-rc.6
languageName: unknown
linkType: soft
"@deepseek-ai/dsh-session@npm:^0.0.1, @deepseek-ai/dsh-session@workspace:packages/session": "@deepseek-ai/dsh-session@npm:^0.0.1, @deepseek-ai/dsh-session@workspace:packages/session":
version: 0.0.0-use.local version: 0.0.0-use.local
resolution: "@deepseek-ai/dsh-session@workspace:packages/session" resolution: "@deepseek-ai/dsh-session@workspace:packages/session"