fix(sync): route directory-less todo updates

packages/ui/src/sync/DOCUMENTATION.md

@@ -168,6 +168,10 @@ Keep this in sync with `handleDirectoryEvent` in `sync-context.tsx`:
 | `question.asked/replied/rejected` | `question` |
 | `lsp.updated` | `lsp` |
 
+### Directory-less session events
+
+The global stream can omit a directory for a session-addressed event. Resolve it through the session routing index first. If the index is briefly stale during a session transition, route only when the event session matches the active session and that directory store exists; otherwise leave it un-routed rather than updating another directory.
+
 ## Adding a new event type
 
 1. Add the case to the event reducer (`event-reducer.ts`)

packages/ui/src/sync/__tests__/session-switch-resync.test.ts

@@ -1,9 +1,10 @@
 import { describe, expect, test, beforeEach, mock } from "bun:test"
 import { create, type StoreApi } from "zustand"
-import type { PermissionRequest, QuestionRequest } from "@opencode-ai/sdk/v2/client"
+import type { Event, PermissionRequest, QuestionRequest } from "@opencode-ai/sdk/v2/client"
 
 const listPendingQuestionsCalls: Array<{ directories?: Array<string | null | undefined> }> = []
 const listPendingPermissionsCalls: Array<{ directories?: Array<string | null | undefined> }> = []
+const todoPersistWrites: Array<{ sessionID: string; todos: unknown }> = []
 let pendingQuestionsResponse: QuestionRequest[] = []
 let pendingPermissionsResponse: PermissionRequest[] = []
 let pendingQuestionsShouldThrow = false
@@ -41,7 +42,22 @@ mock.module("@/stores/useConfigStore", () => ({
 }))
 
 mock.module("@/stores/useTodosPersistStore", () => ({
-  useTodosPersistStore: { getState: () => ({}) },
+  useTodosPersistStore: {
+    getState: () => ({
+      setSessionTodos: (sessionID: string, todos: unknown) => {
+        todoPersistWrites.push({ sessionID, todos })
+      },
+    }),
+  },
+}))
+
+mock.module("sonner", () => ({
+  toast: {
+    dismiss: () => undefined,
+    error: () => undefined,
+    info: () => undefined,
+    success: () => undefined,
+  },
 }))
 
 mock.module("@/components/ui", () => ({
@@ -49,8 +65,13 @@ mock.module("@/components/ui", () => ({
 }))
 
 import { INITIAL_STATE, type State } from "../types"
-import type { DirectoryStore } from "../child-store"
-import { resyncBlockingRequestsForDirectory } from "../sync-context"
+import { ChildStoreManager, type DirectoryStore } from "../child-store"
+const {
+  createEventRoutingIndex,
+  handleEvent,
+  resyncBlockingRequestsForDirectory,
+  setActiveSession,
+} = await import("../sync-context")
 
 function buildQuestion(overrides: Partial<QuestionRequest> = {}): QuestionRequest {
   return {
@@ -91,6 +112,8 @@ describe("resyncBlockingRequestsForDirectory", () => {
     pendingPermissionsResponse = []
     pendingQuestionsShouldThrow = false
     pendingPermissionsShouldThrow = false
+    todoPersistWrites.length = 0
+    setActiveSession("", "")
   })
 
   test("calls listPendingQuestions and listPendingPermissions exactly once for the directory", async () => {
@@ -205,4 +228,56 @@ describe("resyncBlockingRequestsForDirectory", () => {
     expect(store.getState().question["ses_a"]?.[0]?.id).toBe("que_1")
     expect(listPendingPermissionsCalls).toHaveLength(1)
   })
+
+  test("routes a directory-less todo snapshot to its active session during a multi-store routing-index gap", () => {
+    const childStores = new ChildStoreManager()
+    const store = childStores.ensureChild("/target", { bootstrap: false })
+    childStores.ensureChild("/other", { bootstrap: false })
+    const todos = [
+      { content: "Finish plan", status: "completed", priority: "high" },
+      { content: "Implement changes", status: "in_progress", priority: "high" },
+    ]
+    const event = {
+      type: "todo.updated",
+      properties: { sessionID: "ses_a", todos },
+    } as Event
+    const routingIndex = createEventRoutingIndex()
+
+    expect(childStores.children.size).toBe(2)
+    expect(routingIndex.sessionDirectoryById.size).toBe(0)
+    for (const candidate of childStores.children.values()) {
+      const state = candidate.getState()
+      expect(state.session).toEqual([])
+      expect(state.message.ses_a).toBe(undefined)
+      expect(state.session_status.ses_a).toBe(undefined)
+    }
+
+    let storeWrites = 0
+    const unsubscribe = store.subscribe(() => {
+      storeWrites += 1
+    })
+    setActiveSession("/target", "ses_a")
+    handleEvent("global", event, childStores, routingIndex)
+
+    expect(store.getState().todo.ses_a).toEqual(todos)
+    expect(todoPersistWrites).toEqual([{ sessionID: "ses_a", todos }])
+    expect(storeWrites).toBe(1)
+
+    const stateAfterFirstSnapshot = store.getState()
+    const duplicateTodos = todos.map((todo) => ({ ...todo }))
+    const duplicateEvent = {
+      type: "todo.updated",
+      properties: { sessionID: "ses_a", todos: duplicateTodos },
+    } as Event
+    expect(duplicateTodos).not.toBe(todos)
+    expect(duplicateTodos).toEqual(todos)
+
+    handleEvent("global", duplicateEvent, childStores, routingIndex)
+
+    expect(store.getState()).toBe(stateAfterFirstSnapshot)
+    expect(todoPersistWrites).toEqual([{ sessionID: "ses_a", todos }])
+    expect(storeWrites).toBe(1)
+    unsubscribe()
+    childStores.disposeAll()
+  })
 })

packages/ui/src/sync/event-reducer.ts

@@ -286,6 +286,9 @@ export function applyDirectoryEvent(
 
     case "todo.updated": {
       const props = event.properties as { sessionID: string; todos: Todo[] }
+      if (areJsonEquivalent(draft.todo[props.sessionID], props.todos)) {
+        return false
+      }
       draft.todo[props.sessionID] = props.todos
       callbacks?.onSetSessionTodo?.(props.sessionID, props.todos)
       return true

packages/ui/src/sync/sync-context.tsx

@@ -606,7 +606,7 @@ const dispatchVSCodeRuntimeNotificationEvent = (directory: string, payload: Even
   }))
 }
 
-const createEventRoutingIndex = (): EventRoutingIndex => ({
+export const createEventRoutingIndex = (): EventRoutingIndex => ({
   sessionDirectoryById: new Map(),
   messageSessionById: new Map(),
   sessionMessageIdsById: new Map(),
@@ -896,8 +896,12 @@ const childStoreHasMessagePartState = (
   return Object.prototype.hasOwnProperty.call(store.getState().part, messageID)
 }
 
-const getActiveDirectoryFallback = (childStores: ChildStoreManager): string | null => {
+const getActiveDirectoryFallback = (
+  childStores: ChildStoreManager,
+  sessionID?: string | null,
+): string | null => {
   if (!_activeDirectory || !_activeSession) return null
+  if (sessionID && sessionID !== _activeSession) return null
   return childStores.getChild(_activeDirectory) ? _activeDirectory : null
 }
 
@@ -927,6 +931,14 @@ const resolveDirectoryFromRoutingIndex = (
     if (found) {
       return found
     }
+
+    // The global stream does not always include a directory. During a session
+    // transition, its routing index can lag the active session briefly; route
+    // a session-addressed event only when that session is the one being viewed.
+    const activeDirectory = getActiveDirectoryFallback(childStores, sessionID)
+    if (activeDirectory) {
+      return activeDirectory
+    }
   }
 
   const messageID = getMessageIdFromPayload(payload)
@@ -1351,7 +1363,7 @@ async function resyncDirectoryAfterReconnect(
   ingestDirectoryStateIntoRoutingIndex(routingIndex, directory, store.getState())
 }
 
-function handleEvent(
+export function handleEvent(
   rawDirectory: string,
   payload: Event,
   childStores: ChildStoreManager,