fix(subagent): await pending descendants during activation disposal

packages/subagent/subagent/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/subagent/subagent/README.md
-README.md: a90d160234e6169639a35481cfd9bb19eac614f4
-README.zh.md: b7c0d22fa40697736d7c982cb582078b115ae94c
+README.md: ae8b0f629a6dcb1e4ec8176b1f5dd2fa18cddf50
+README.zh.md: 822f64a3db43ab1b4bfd679f00d503c31f5d6d12

packages/subagent/subagent/README.md

@@ -64,7 +64,7 @@ Every exact live Agent can use `sendMessage()` with a direct continuable child;
 
 ### Failure and recovery
 
-Unsupported provider capabilities reject creation. The caller signal cancels only unpublished work; after publication, `dispose()` cancels the exact activation and waits for its descendants and resources. `result` settles after teardown and notifications, carrying output, optional structured data, and a stop reason; capture failures reject it after teardown. Cleanup failures reject `dispose()` without replacing a captured execution result.
+Unsupported provider capabilities reject creation. The caller signal cancels only unpublished work; after publication, `dispose()` cancels the exact activation and waits for its descendants, including pending startups, and their resource cleanup. `result` settles after teardown and notifications, carrying output, optional structured data, and a stop reason; capture failures reject it after teardown. Cleanup failures reject `dispose()` without replacing a captured execution result.
 
 -----
 

packages/subagent/subagent/README.zh.md

@@ -64,7 +64,7 @@ kind: "package-reference"
 
 ### 失败与恢复
 
-不受提供方支持的能力会使创建失败。调用方信号仅取消尚未发布的工作；发布后通过 `dispose()` 取消该次 activation，并等待其后代和资源释放。`result` 在清理与通知结束后完成，携带输出、可选结构化数据与停止原因；结果捕获故障在清理后使其拒绝。清理失败使 `dispose()` 拒绝，不覆盖已捕获的执行结果。
+不受提供方支持的能力会使创建失败。调用方信号仅取消尚未发布的工作；发布后通过 `dispose()` 取消该次 activation，并等待其后代（包括正在启动的后代）及其资源清理完成。`result` 在清理与通知结束后完成，携带输出、可选结构化数据与停止原因；结果捕获故障在清理后使其拒绝。清理失败使 `dispose()` 拒绝，不覆盖已捕获的执行结果。
 
 -----
 

packages/subagent/subagent/src/manager.ts

@@ -1025,7 +1025,7 @@ export class SubagentManager {
     return 'ready'
   }
 
-  /** Propagate stop synchronously, then finish the child-first release. */
+  /** Propagate stop synchronously and await descendant startup rollback before release. */
   private async finishDisposal(activation: Activation, stop: boolean): Promise<void> {
     this.wake(activation)
     const { childId } = activation
@@ -1055,7 +1055,10 @@ export class SubagentManager {
           const children = [...activation.ownedChildren]
             .map(child => this.resident.get(child))
             .filter((child): child is Activation => child !== undefined)
+          const pending = [...this.materializations].filter(item => item.lineage.includes(activation.handle.agent))
           const childDisposals = children.map(child => this.dispose(child))
+          for (const item of pending) item.controller.abort()
+          childDisposals.push(...pending.map(item => item.settled))
           const childFailures = await Promise.all(childDisposals.map(async (disposal) => {
             try {
               await disposal

packages/subagent/subagent/tests/continuation.spec.ts

@@ -3481,6 +3481,63 @@ describe('continuable errors', () => {
     await drained
   })
 
+  it.each([1, 2])('disposes a local activation only after pending startup at depth %s rolls back', async (depth) => {
+    const { ctx, parent } = await setup(Array.from({ length: depth }, () => 'hang' as const))
+    const started = await ctx.subagents.startActivation({ ...startSpec(parent), delivery: 'caller' })
+    const child = ctx.agents.get(started.childId)!
+    const entered = Promise.withResolvers<AbortSignal>()
+    const releaseStartup = Promise.withResolvers<undefined>()
+    const cleaning = Promise.withResolvers<undefined>()
+    const releaseCleanup = Promise.withResolvers<undefined>()
+    let starting: Promise<unknown> | undefined
+    let disposal: Promise<void> | undefined
+    try {
+      let owner = child
+      for (let level = 1; level < depth; level++) {
+        const nested = await ctx.subagents.startActivation({ ...startSpec(owner), delivery: 'caller' })
+        owner = ctx.agents.get(nested.childId)!
+      }
+      ctx.subagents.registerProvider({
+        name: 'external', inheritsParentContext: false,
+        capabilities: { agentOptions: false, outputSchema: false, depthLimit: false, toolFilter: false, persona: false },
+        start: async ({ signal }) => {
+          entered.resolve(signal)
+          await releaseStartup.promise
+          return {
+            id: SessionId('pending-descendant'),
+            result: Promise.resolve({ output: [], stopReason: 'completed' }),
+            dispose: async () => { cleaning.resolve(undefined); await releaseCleanup.promise },
+          }
+        },
+      })
+      starting = ctx.subagents.startActivation({ ...startSpec(owner, 'external'), delivery: 'caller' })
+        .catch((error: unknown) => error)
+      const signal = await entered.promise
+      disposal = started.dispose()
+      const disposed = vi.fn()
+      void disposal.then(disposed, disposed)
+      expect(signal.aborted).toBe(true)
+      await expect(ctx.subagents.startActivation({ ...startSpec(child), delivery: 'caller' }))
+        .rejects.toMatchObject({ code: 'ACTIVATION_CLOSING' })
+      releaseStartup.resolve(undefined)
+      await cleaning.promise
+      expect(disposed).not.toHaveBeenCalled()
+      expect(ctx.agents.get(child.id)).toBe(child)
+      releaseCleanup.resolve(undefined)
+      await disposal
+      await expect(starting).resolves.toMatchObject({ name: 'AbortError' })
+      expect(ctx.agents.get(child.id)).toBeUndefined()
+      expect(ctx.agents.get(owner.id)).toBeUndefined()
+      expect(ctx.agents.get(parent.id)).toBe(parent)
+      await expect(ctx.subagents.waitForChildren(parent)).resolves.toBe(false)
+    } finally {
+      releaseStartup.resolve(undefined)
+      releaseCleanup.resolve(undefined)
+      await Promise.allSettled([starting, disposal, started.dispose()])
+      await ctx.fiber.dispose()
+    }
+  })
+
   it('reports a failing branch after every branch settles, without pinning the rest', async () => {
     const hold = Promise.withResolvers<undefined>()
     const adapter = new GatedAdapter([
@@ -3545,7 +3602,7 @@ describe('continuable errors', () => {
     }
   })
 
-  it('rolls the transfer back when the parent begins disposal during materialization', async () => {
+  it.each(['agent/created', 'subagent/start'] as const)('rejects child admission when parent disposal begins at %s', async (event) => {
     const hold = Promise.withResolvers<undefined>()
     const adapter = new GatedAdapter([
       { chunks: textResponse('parent child'), gate: hold.promise },
@@ -3558,29 +3615,18 @@ describe('continuable errors', () => {
       expect(found).toBeDefined()
       return found!
     })
-    const activations = managerState(ctx)
-    const ownerAgents = activations.ownerCtx.agents
     const before = new Set(ctx.agents.list().map(agent => agent.id))
-    // Open the would-be parent's disposal only once the grandchild's Agent is
-    // being created: the entry hold has already passed, so the post-transfer
-    // ownership registration must reject and roll the transfer back with no
-    // Activation and no live Agent left behind.
-    const originalCreate = ownerAgents.create.bind(ownerAgents)
     let disposal: Promise<void> | undefined
-    const createSpy = vi.spyOn(ownerAgents, 'create').mockImplementation((options) => {
-      disposal = outer.dispose()
-      createSpy.mockRestore()
-      return originalCreate(options)
-    })
+    const detach = ctx.on(event, () => { disposal = outer.dispose() })
 
     try {
       await expect(ctx.subagents.startActivation({ ...startSpec(child), delivery: 'parent' }))
-        .rejects.toMatchObject({ code: 'ACTIVATION_CLOSING' })
+        .rejects.toMatchObject(event === 'agent/created' ? { name: 'AbortError' } : { code: 'ACTIVATION_CLOSING' })
       await vi.waitFor(() => {
         expect(ctx.agents.list().map(agent => agent.id).filter(id => !before.has(id))).toEqual([])
       })
     } finally {
-      createSpy.mockRestore()
+      detach()
       hold.resolve(undefined)
       await disposal
     }