feat: refactor parent-child task coordination to use event-driven architecture

- Add parentTaskId field to HistoryItem schema for persistent task relationships
- Replace polling mechanism (waitForResume/pauseInterval) with event-driven approach using TaskUnpaused events
- Update ClineProvider to persist parent task ID when creating child tasks
- Update task metadata persistence to include parentTaskId
- Add comprehensive tests for parent-child task coordination
- Improve performance by eliminating 100ms polling intervals

Fixes #6672

Author: roomote

packages/types/src/history.ts

@@ -17,6 +17,7 @@ export const historyItemSchema = z.object({
 	size: z.number().optional(),
 	workspace: z.string().optional(),
 	mode: z.string().optional(),
+	parentTaskId: z.string().optional(),
 })
 
 export type HistoryItem = z.infer<typeof historyItemSchema>

src/core/task-persistence/taskMetadata.ts

@@ -19,6 +19,7 @@ export type TaskMetadataOptions = {
 	globalStoragePath: string
 	workspace: string
 	mode?: string
+	parentTaskId?: string
 }
 
 export async function taskMetadata({
@@ -28,6 +29,7 @@ export async function taskMetadata({
 	globalStoragePath,
 	workspace,
 	mode,
+	parentTaskId,
 }: TaskMetadataOptions) {
 	const taskDir = await getTaskDirectoryPath(globalStoragePath, taskId)
 
@@ -95,6 +97,7 @@ export async function taskMetadata({
 		size: taskDirSize,
 		workspace,
 		mode,
+		parentTaskId,
 	}
 
 	return { historyItem, tokenUsage }

src/core/task/Task.ts

@@ -183,7 +183,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	isInitialized = false
 	isPaused: boolean = false
 	pausedModeSlug: string = defaultModeSlug
-	private pauseInterval: NodeJS.Timeout | undefined
+	private pauseResolve: (() => void) | undefined
 
 	// API
 	readonly apiConfiguration: ProviderSettings
@@ -586,6 +586,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 				globalStoragePath: this.globalStoragePath,
 				workspace: this.cwd,
 				mode: this._taskMode || defaultModeSlug, // Use the task's own mode, not the current provider mode
+				parentTaskId: this.parentTask?.taskId,
 			})
 
 			this.emit(RooCodeEventName.TaskTokenUsageUpdated, this.taskId, tokenUsage)
@@ -1221,10 +1222,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	public dispose(): void {
 		console.log(`[Task] disposing task ${this.taskId}.${this.instanceId}`)
 
-		// Stop waiting for child task completion.
-		if (this.pauseInterval) {
-			clearInterval(this.pauseInterval)
-			this.pauseInterval = undefined
+		// If waiting for resume, resolve the promise to unblock
+		if (this.pauseResolve) {
+			this.pauseResolve()
+			this.pauseResolve = undefined
 		}
 
 		// Release any terminals associated with this task.
@@ -1300,18 +1301,18 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	}
 
 	// Used when a sub-task is launched and the parent task is waiting for it to
-	// finish.
-	// TBD: The 1s should be added to the settings, also should add a timeout to
-	// prevent infinite waiting.
+	// finish. Uses event-driven approach instead of polling.
 	public async waitForResume() {
 		await new Promise<void>((resolve) => {
-			this.pauseInterval = setInterval(() => {
-				if (!this.isPaused) {
-					clearInterval(this.pauseInterval)
-					this.pauseInterval = undefined
-					resolve()
+			this.pauseResolve = resolve
+
+			// Set up event listener for TaskUnpaused event
+			const unsubscribe = this.once(RooCodeEventName.TaskUnpaused, () => {
+				if (this.pauseResolve) {
+					this.pauseResolve()
+					this.pauseResolve = undefined
 				}
-			}, 1000)
+			})
 		})
 	}