feat(trajectory): virtualize long session histories

packages/client/runtime/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/runtime/README.md
-README.md: 89e58f967f852bb0786a5b7d73fa8e924fa282e0
-README.zh.md: 960e2fceede1b500af9ee2063ec9283e2b7b271a
+README.md: 3e9bcdd587764ee21326c27e0cd642914cf84f8f
+README.zh.md: 8e13bc3d09ae220f7a64640b21892c03a37bae29

packages/client/runtime/README.md

@@ -2,7 +2,7 @@
 
 English | [中文](README.zh.md)
 
-Client cordis boot and React-free object services: SlotsService wraps SlotCore and supplies renderer data sources; SessionsService owns Session objects and the Chat-facing list, scope, and event-window state; SessionHistoryService lazily owns independent raw-history ledgers for inspection consumers; WorkspacesService depends on SessionsService and owns Workspace objects, list/actions, default-target derivation, and the New Session blank-reuse entry (`connectWorkspace`). The runtime fans the shared Host stream into the Session, Workspace, and activated history owners without routing inspection state through Session or SessionManager, and bridges the registry-invalidation frames to typed ctx events (`commands/changed`, `settings/changed`, `credentials/changed`, `models/changed`) so surface caches refetch without touching the stream. Client sessions are always Host-born (Session+Agent+cwd in one `session.create`); the client holds no pre-entity session state — a session's Agent scope (the client mirror of host dsh-scope, keyed by the shared agent/session id) is born when its row enters the list mirror and dies with the prune. Contract: api-contracts v3 §4. Each `Session` holds a generic `ProjectionValueStore` seeded from the history-tail `projections` block and updated by `session/projection` frames under higher-seq-wins; domain keys (including `todos`) are read via `projections.faceOf` / `useProjection`, not via `ConversationSnapshot`. The store also publishes one reference-stable whole-value map through `SessionSummary.projectionValues`, allowing global list consumers to reuse the same projections without creating per-session subscriptions.
+Client cordis boot and React-free object services: SlotsService wraps SlotCore and supplies renderer data sources; SessionsService owns Session objects and the Chat-facing list, scope, and event-window state; SessionHistoryService lazily owns independent raw-history ledgers for inspection consumers, loading the current tail first and prepending one older page only when its consumer requests it; WorkspacesService depends on SessionsService and owns Workspace objects, list/actions, default-target derivation, and the New Session blank-reuse entry (`connectWorkspace`). The runtime fans the shared Host stream into the Session, Workspace, and activated history owners without routing inspection state through Session or SessionManager, and bridges the registry-invalidation frames to typed ctx events (`commands/changed`, `settings/changed`, `credentials/changed`, `models/changed`) so surface caches refetch without touching the stream. Client sessions are always Host-born (Session+Agent+cwd in one `session.create`); the client holds no pre-entity session state — a session's Agent scope (the client mirror of host dsh-scope, keyed by the shared agent/session id) is born when its row enters the list mirror and dies with the prune. Contract: api-contracts v3 §4. Each `Session` holds a generic `ProjectionValueStore` seeded from the history-tail `projections` block and updated by `session/projection` frames under higher-seq-wins; domain keys (including `todos`) are read via `projections.faceOf` / `useProjection`, not via `ConversationSnapshot`. The store also publishes one reference-stable whole-value map through `SessionSummary.projectionValues`, allowing global list consumers to reuse the same projections without creating per-session subscriptions.
 
 ## Workspace and Session lists
 

packages/client/runtime/README.zh.md

@@ -2,7 +2,7 @@
 
 [English](README.md) | 中文
 
-客户端 cordis 启动与不依赖 React 的对象服务：SlotsService 包装 SlotCore 并提供 renderer 数据源；SessionsService 拥有 Session 对象以及 Chat 所需的列表、scope 和事件窗口状态；SessionHistoryService 为检查类消费方惰性拥有彼此独立的原始历史账本；WorkspacesService 依赖 SessionsService，拥有 Workspace 对象、列表／操作、默认目标派生，以及 New Session 空会话复用入口（`connectWorkspace`）。运行时把共享 Host 流分发给 Session、Workspace 和已激活的历史数据所有者，不让检查状态经过 Session 或 SessionManager，并把注册表失效帧桥接为类型化 ctx 事件（`commands/changed`、`settings/changed`、`credentials/changed`、`models/changed`），使各表面缓存无需触碰流即可重拉。客户端会话一律由 Host 创建（一次 `session.create` 同时产生 Session、agent（智能体）和 cwd）；客户端不持有任何实体化之前的会话状态——agent scope（host dsh-scope 的客户端镜像，以 agent/session 共用 id 为键）在会话行进入列表镜像时创建，并随 prune 销毁。契约：api-contracts v3 §4。每个 `Session` 持有一个通用的 `ProjectionValueStore`，由历史记录尾部的 `projections` 块播种，并经 `session/projection` 帧按 seq 高者胜更新；领域键（含 `todos`）经 `projections.faceOf`／`useProjection` 读取，不经 `ConversationSnapshot`。该 store 还会通过 `SessionSummary.projectionValues` 发布一份引用稳定的完整值映射，使全局列表消费方无需为每个会话创建订阅，即可复用同一组投影。
+客户端 cordis 启动与不依赖 React 的对象服务：SlotsService 包装 SlotCore 并提供 renderer 数据源；SessionsService 拥有 Session 对象以及 Chat 所需的列表、scope 和事件窗口状态；SessionHistoryService 为检查类消费方惰性拥有彼此独立的原始历史账本，先加载当前尾部，并仅在消费方请求时向前补入一页更早历史；WorkspacesService 依赖 SessionsService，拥有 Workspace 对象、列表／操作、默认目标派生，以及 New Session 空会话复用入口（`connectWorkspace`）。运行时把共享 Host 流分发给 Session、Workspace 和已激活的历史数据所有者，不让检查状态经过 Session 或 SessionManager，并把注册表失效帧桥接为类型化 ctx 事件（`commands/changed`、`settings/changed`、`credentials/changed`、`models/changed`），使各表面缓存无需触碰流即可重拉。客户端会话一律由 Host 创建（一次 `session.create` 同时产生 Session、agent（智能体）和 cwd）；客户端不持有任何实体化之前的会话状态——agent scope（host dsh-scope 的客户端镜像，以 agent/session 共用 id 为键）在会话行进入列表镜像时创建，并随 prune 销毁。契约：api-contracts v3 §4。每个 `Session` 持有一个通用的 `ProjectionValueStore`，由历史记录尾部的 `projections` 块播种，并经 `session/projection` 帧按 seq 高者胜更新；领域键（含 `todos`）经 `projections.faceOf`／`useProjection` 读取，不经 `ConversationSnapshot`。该 store 还会通过 `SessionSummary.projectionValues` 发布一份引用稳定的完整值映射，使全局列表消费方无需为每个会话创建订阅，即可复用同一组投影。
 
 ## Workspace 与 Session 列表
 

packages/client/runtime/src/client/contract/session-history.ts

@@ -17,11 +17,17 @@ export interface SessionHistoryFace
   extends ObservableSnapshot<SessionHistorySnapshot> {
   readonly sessionId: SessionId
   /**
-   * Load the tail and exhaust every available older page.
-   * @param signal - Consumer lifetime; abort is observed between page requests.
-   * @returns When the available ledger is complete or stops advancing.
+   * Load the current tail without reading older pages.
+   * @param signal - Consumer lifetime.
+   * @returns When the tail is ready or loading fails.
    */
-  loadAll(signal?: AbortSignal): Promise<void>
+  loadTail(signal?: AbortSignal): Promise<void>
+  /**
+   * Prepend one older page when the current window has a predecessor.
+   * @param signal - Consumer lifetime.
+   * @returns Whether the loaded window advanced.
+   */
+  loadOlder(signal?: AbortSignal): Promise<boolean>
 }
 
 /** Runtime service resolving independent history sources. */

packages/client/runtime/src/client/session-history/source.ts

@@ -36,7 +36,6 @@ export class SessionHistorySource implements SessionHistoryFace {
     value: SessionHistorySnapshot['inspection']
   } | null = null
   private streamPublishToken: object | null = null
-  private streamBaseInspection: SessionHistorySnapshot['inspection'] | null = null
   private streamPartial: PartialAccumulator | null = null
   private snapshotCache: SessionHistorySnapshot
   private readonly notifier = new Notifier(() => {
@@ -73,37 +72,34 @@ export class SessionHistorySource implements SessionHistoryFace {
   }
 
   /**
-   * Load the tail and exhaust all available older pages.
+   * Load the current tail without reading older pages.
    * @param signal - Consumer lifetime.
-   * @returns When paging completes, fails to advance, or is aborted.
+   * @returns When the tail is ready or loading fails.
    */
-  async loadAll(signal?: AbortSignal): Promise<void> {
-    if (signal?.aborted === true) return
+  async loadTail(signal?: AbortSignal): Promise<void> {
+    if (isAborted(signal)) return
     this.trackConsumer(signal)
     await this.open()
-    while (
-      !isAborted(signal)
-      && this.state === 'ready'
-      && this.hasMore
-    ) {
-      const previousBaseSeq = this.baseSeq
-      await this.loadOlder()
-      if (isAborted(signal) || this.baseSeq === previousBaseSeq) return
-    }
   }
 
-  /** Rebuild and page for whichever mounted consumers survive a reconnect. */
+  /**
+   * Prepend one older page when the current window has a predecessor.
+   * @param signal - Consumer lifetime.
+   * @returns Whether the loaded window advanced.
+   */
+  async loadOlder(signal?: AbortSignal): Promise<boolean> {
+    if (isAborted(signal)) return false
+    this.trackConsumer(signal)
+    await this.open()
+    if (isAborted(signal)) return false
+    const previousBaseSeq = this.baseSeq
+    await this.loadOlderPage()
+    return this.baseSeq !== previousBaseSeq
+  }
+
+  /** Rebuild the tail for whichever mounted consumers survive a reconnect. */
   private async loadForConsumers(): Promise<void> {
     await this.open()
-    while (
-      this.hasConsumer()
-      && this.state === 'ready'
-      && this.hasMore
-    ) {
-      const previousBaseSeq = this.baseSeq
-      await this.loadOlder()
-      if (!this.hasConsumer() || this.baseSeq === previousBaseSeq) return
-    }
   }
 
   /**
@@ -161,7 +157,6 @@ export class SessionHistorySource implements SessionHistoryFace {
     this.olderPromise = null
     this.liveBuffer = []
     this.streamPublishToken = null
-    this.streamBaseInspection = null
     this.streamPartial = null
   }
 
@@ -234,7 +229,7 @@ export class SessionHistorySource implements SessionHistoryFace {
     }
   }
 
-  private loadOlder(): Promise<void> {
+  private loadOlderPage(): Promise<void> {
     if (this.olderPromise !== null) return this.olderPromise
     if (this.state !== 'ready' || !this.hasMore) return Promise.resolve()
     const generation = this.generation
@@ -339,8 +334,7 @@ export class SessionHistorySource implements SessionHistoryFace {
       this.inspectionCache = { entries: this.entries, value: inspection }
       return false
     }
-    const base = this.streamBaseInspection ?? this.currentInspection()
-    this.streamBaseInspection = base
+    const base = this.currentInspection()
     if (
       this.streamPartial === null
       || this.streamPartial.turn !== turn
@@ -382,7 +376,6 @@ export class SessionHistorySource implements SessionHistoryFace {
   /** Publish structural changes immediately and invalidate an older scheduled stream publish. */
   private publishDirtyNow(): void {
     this.streamPublishToken = null
-    this.streamBaseInspection = null
     this.streamPartial = null
     this.notifier.markDirty()
   }

packages/client/runtime/tests/session-history-source.spec.ts

@@ -16,7 +16,7 @@ function histResponse(events: SessionEvent[], hasMore = false) {
 }
 
 describe('SessionHistorySource', () => {
-  it('loads every older page without changing a Chat session', async () => {
+  it('loads the tail first and prepends older pages on demand', async () => {
     const pages = [
       plainTurn(0, 0, '最早问', '最早答'),
       plainTurn(6, 1, '中间问', '中间答'),
@@ -30,7 +30,16 @@ describe('SessionHistorySource', () => {
     }
     const source = new SessionHistorySource(SID, api)
 
-    await source.loadAll()
+    await source.loadTail()
+
+    expect(api.callsOf('session.history')).toHaveLength(1)
+    expect(source.getSnapshot().hasMore).toBe(true)
+    expect(source.getSnapshot().inspection.eventNodes.map(node => node.seq))
+      .toEqual([13, 15])
+
+    expect(await source.loadOlder()).toBe(true)
+    expect(await source.loadOlder()).toBe(true)
+    expect(await source.loadOlder()).toBe(false)
 
     expect(api.callsOf('session.history')).toHaveLength(3)
     expect(source.getSnapshot().hasMore).toBe(false)
@@ -42,7 +51,7 @@ describe('SessionHistorySource', () => {
     const api = new FakeApiClient()
     api.onHistory = () => histResponse(plainTurn(0, 0, '问', '答'))
     const source = new SessionHistorySource(SID, api)
-    await source.loadAll()
+    await source.loadTail()
     const before = source.getSnapshot()
 
     source.handleMuxFrame({
@@ -60,7 +69,7 @@ describe('SessionHistorySource', () => {
     const api = new FakeApiClient()
     api.onHistory = () => histResponse(plainTurn(0, 0, '问', '答'))
     const source = new SessionHistorySource(SID, api)
-    await source.loadAll()
+    await source.loadTail()
     const frames: FrameRequestCallback[] = []
     vi.stubGlobal('requestAnimationFrame', (callback: FrameRequestCallback) => {
       frames.push(callback)
@@ -132,13 +141,14 @@ describe('SessionHistorySource', () => {
       }))
     const source = new SessionHistorySource(SID, api)
 
-    await source.loadAll()
+    await source.loadTail()
+    expect(await source.loadOlder()).toBe(false)
 
     expect(api.callsOf('session.history')).toHaveLength(2)
     expect(source.getSnapshot().hasMore).toBe(true)
   })
 
-  it('observes consumer cancellation between older pages', async () => {
+  it('finishes an already started older page after consumer cancellation', async () => {
     const middle = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
     const olderStarted = deferred<undefined>()
     const api = new FakeApiClient()
@@ -151,7 +161,8 @@ describe('SessionHistorySource', () => {
     }
     const source = new SessionHistorySource(SID, api)
     const controller = new AbortController()
-    const complete = source.loadAll(controller.signal)
+    await source.loadTail(controller.signal)
+    const complete = source.loadOlder(controller.signal)
     await olderStarted.promise
     controller.abort()
     middle.resolve(ok({
@@ -159,7 +170,7 @@ describe('SessionHistorySource', () => {
       hasMore: true,
     }))
 
-    await complete
+    expect(await complete).toBe(true)
 
     expect(api.callsOf('session.history')).toHaveLength(2)
     expect(source.getSnapshot().hasMore).toBe(true)