feat(client): increment forked session titles

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: db6388dccee6e065066cc70e141073d99822ce0f
-README.zh.md: e1b6902d0d30972bd613553081e0f0e8d5da2a05
+README.md: b85deeec92fd4da1f342b5536757692f594853a5
+README.zh.md: 2dbb66c56ad5687fb299fe030d0abfe451004a62

packages/client/runtime/README.md

@@ -30,7 +30,7 @@ SlotsService gives the renderer separate bare observables for `useSessions` and
 
 ## Session forking
 
-`ISessions.fork({sessionId, atSeq?})` resolves only after the child summary is locally addressable, carrying source lineage and cwd with `blank: false`; callers choose whether to open it. A `workspace-attach-failed` response still identifies a child already published by the Host, so `SessionManager` reconciles that partial success before `SessionForkError` reaches the caller instead of making a retry create a duplicate child.
+`ISessions.fork({sessionId, atSeq?, increaseTitle?})` resolves only after the child summary is locally addressable, carrying source lineage and cwd with `blank: false`; callers choose whether to open it. With `increaseTitle: true`, the client renames the child from the source session's persisted title: a trailing `(N)` or `（N）` is incremented without changing bracket style, while any other title gets ` (1)` appended; the rename is skipped when the source has no persisted title, and a rename failure rejects the promise but leaves the created child in place. This option is not sent in the Host fork request. A `workspace-attach-failed` response still identifies a child already published by the Host, so `SessionManager` reconciles that partial success before `SessionForkError` reaches the caller instead of making a retry create a duplicate child.
 
 ## Session model selection
 

packages/client/runtime/README.zh.md

@@ -30,7 +30,7 @@ SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸
 
 ## 会话 fork
 
-`ISessions.fork({sessionId, atSeq?})` 只在子会话摘要已能在本地寻址后才完成；该摘要携带源会话的谱系和 cwd，且 `blank: false`，由调用方决定是否打开。即使响应为 `workspace-attach-failed`，其中仍会标识 Host 已发布的子会话，因此 `SessionManager` 会先将这一部分成功对账，再让 `SessionForkError` 到达调用方，避免重试创建重复的子会话。
+`ISessions.fork({sessionId, atSeq?, increaseTitle?})` 只在子会话摘要已能在本地寻址后才完成；该摘要携带源会话的谱系和 cwd，且 `blank: false`，由调用方决定是否打开。`increaseTitle: true` 会在 client 端把源会话的持久化标题改名到子会话：尾部 `(N)` 或 `（N）` 递增并保留括号样式，其余标题追加 ` (1)`；源会话没有持久化标题时跳过改名，改名失败时拒绝 promise 但保留已创建的子会话。该选项不会进入 Host fork 请求。即使响应为 `workspace-attach-failed`，其中仍会标识 Host 已发布的子会话，因此 `SessionManager` 会先将这一部分成功对账，再让 `SessionForkError` 到达调用方，避免重试创建重复的子会话。
 
 ## 会话模型选择
 

packages/client/runtime/src/client/contract/sessions.ts

@@ -32,12 +32,14 @@ export interface ISessions {
   /**
    * Fork a session from a completed-turn prefix of the source; on resolution
    * the child is in the list store and `open()` can target it.
-   * @param opts - source session id and the optional event seq anchoring the
+   * @param opts - source session id, the optional event seq anchoring the
    *   cut (the boundary is the first turn/end at or after it; an in-log
-   *   anchor in an open turn is unavailable rather than clipped backward).
+   *   anchor in an open turn is unavailable rather than clipped backward),
+   *   and whether to increment an inherited durable title before resolving.
    * @returns the child session id.
+   * @throws when the fork fails, or when a requested child-title rename fails after creation.
    */
-  fork(opts: { sessionId: SessionId; atSeq?: number }): Promise<SessionId>
+  fork(opts: { sessionId: SessionId; atSeq?: number; increaseTitle?: boolean }): Promise<SessionId>
   /**
    * Register a per-session standard-props provider (hooks become `use<Name>`
    * selector hooks on the render side; props spread verbatim).

packages/client/runtime/src/client/sessions/service.ts

@@ -137,6 +137,24 @@ function displayTitleOf(title: string | undefined, cwd: string | undefined, id:
   return id
 }
 
+/**
+ * Increment a trailing fork number while preserving its half-width or
+ * full-width parentheses; an unnumbered title starts with ` (1)`.
+ * @param title - source session's durable title.
+ * @returns the title assigned to the fork child.
+ */
+function increasedForkTitle(title: string): string {
+  const ascii = /^(.*?)\((\d+)\)$/u.exec(title)
+  if (ascii?.[1] !== undefined && ascii[2] !== undefined) {
+    return `${ascii[1]}(${BigInt(ascii[2]) + 1n})`
+  }
+  const fullWidth = /^(.*?)（(\d+)）$/u.exec(title)
+  if (fullWidth?.[1] !== undefined && fullWidth[2] !== undefined) {
+    return `${fullWidth[1]}（${BigInt(fullWidth[2]) + 1n}）`
+  }
+  return `${title} (1)`
+}
+
 interface ScopeRecord {
   fiber: Fiber
   ctx: Context
@@ -337,17 +355,36 @@ export class SessionsService implements ISessions {
    * Fork a session from a completed-turn prefix of the source (same
    * synchronous-addressability guarantee as {@link SessionsService.create}:
    * on resolution the child is in the list store and open() can target it).
-   * @param opts - source session id and the optional event seq anchoring the
+   * @param opts - source session id, the optional event seq anchoring the
    *   cut (the boundary is the first turn/end at or after it; an in-log
-   *   anchor in an open turn is unavailable rather than clipped backward).
+   *   anchor in an open turn is unavailable rather than clipped backward),
+   *   and whether to increment an inherited durable title before resolving.
    * @returns the child session id.
    * @throws {SessionForkError} with the source id.
+   * @throws {Error} when a requested child-title rename fails after creation.
    */
-  async fork(opts: { sessionId: SessionId; atSeq?: number }): Promise<SessionId> {
-    const result = await this.manager.fork(opts)
+  async fork(opts: {
+    sessionId: SessionId
+    atSeq?: number
+    increaseTitle?: boolean
+  }): Promise<SessionId> {
+    const sourceTitle = opts.increaseTitle
+      ? this.list.getSnapshot().byId[opts.sessionId]?.title
+      : undefined
+    const result = await this.manager.fork({
+      sessionId: opts.sessionId,
+      ...(opts.atSeq === undefined ? {} : { atSeq: opts.atSeq }),
+    })
     if (!result.ok) throw new SessionForkError(result.error, opts.sessionId)
     this.projectList()
-    return result.value.sessionId
+    const childId = result.value.sessionId
+    if (sourceTitle !== undefined) {
+      const child = this.binding(childId)?.session
+      if (child === undefined) throw new Error(`fork child "${childId}" is not locally addressable`)
+      const renamed = await child.rename(increasedForkTitle(sourceTitle))
+      if (!renamed.ok) throw new Error(`fork child rename failed: ${renamed.error.code}: ${renamed.error.message}`)
+    }
+    return childId
   }
 
   /**

packages/client/runtime/tests/sessions-service.spec.ts

@@ -10,7 +10,7 @@ import { Context } from 'cordis'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
 import { SessionCreateError, SessionsService, scopeOf } from '../src/client/sessions/service.ts'
-import { FakeApiClient, deferred, ok } from './fake-api.ts'
+import { FakeApiClient, deferred, err, ok } from './fake-api.ts'
 
 const sid = (s: string): SessionId => s as SessionId
 
@@ -399,6 +399,69 @@ describe('create', () => {
   })
 })
 
+describe('fork', () => {
+  it.each([
+    ['Roadmap', 'Roadmap (1)'],
+    ['Roadmap (1)', 'Roadmap (2)'],
+    ['计划（1）', '计划（2）'],
+    ['计划 （9）', '计划 （10）'],
+  ])('increments the durable title %j after the child is published', async (sourceTitle, childTitle) => {
+    const b = bench()
+    b.svc.handleMuxEnvelope({
+      rpcId: 'source-title' as never,
+      payload: { type: 'session/projection', sessionId: sid('source'), key: 'title', value: sourceTitle, seq: 2 } as never,
+    })
+    await feedList(b, [{ id: 'source', cwd: '/work' }])
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child') }))
+    b.api.onRename = (payload) => {
+      const { title } = payload as { title: string }
+      return Promise.resolve(ok({ title, seq: 3 }))
+    }
+
+    await expect(b.svc.fork({
+      sessionId: sid('source'), atSeq: 7, increaseTitle: true,
+    })).resolves.toBe('child')
+
+    expect(b.api.callsOf('session.fork')).toEqual([{ sessionId: 'source', atSeq: 7 }])
+    expect(b.api.callsOf('session.rename')).toEqual([{ sessionId: 'child', title: childTitle }])
+    await Promise.resolve()
+    expect(b.svc.list.getSnapshot().byId[sid('child')]).toMatchObject({
+      title: childTitle,
+      displayTitle: childTitle,
+      parentId: 'source',
+    })
+  })
+
+  it('does not rename without the title policy or a durable source title', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 'source', cwd: '/work' }])
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child') }))
+    await expect(b.svc.fork({ sessionId: sid('source'), increaseTitle: true })).resolves.toBe('child')
+    expect(b.api.callsOf('session.rename')).toEqual([])
+
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child-2') }))
+    await expect(b.svc.fork({ sessionId: sid('source') })).resolves.toBe('child-2')
+    expect(b.api.callsOf('session.rename')).toEqual([])
+  })
+
+  it('rejects when child rename fails while keeping the published child addressable', async () => {
+    const b = bench()
+    b.svc.handleMuxEnvelope({
+      rpcId: 'source-title' as never,
+      payload: { type: 'session/projection', sessionId: sid('source'), key: 'title', value: 'Roadmap', seq: 2 } as never,
+    })
+    await feedList(b, [{ id: 'source' }])
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child') }))
+    b.api.onRename = () => Promise.resolve(err({
+      code: 'title-invalid', message: 'rejected', details: { sessionId: sid('child') },
+    }))
+
+    await expect(b.svc.fork({ sessionId: sid('source'), increaseTitle: true }))
+      .rejects.toThrow('fork child rename failed: title-invalid: rejected')
+    expect(b.svc.binding(sid('child'))).toBeDefined()
+  })
+})
+
 describe('scope lifecycle rides the list mirror (entity parity: no client-side pre-birth)', () => {
   it('a session-added frame births the row (blank) and makes the scope resolvable; removal prunes it', async () => {
     const b = bench()