fix: Preserve parent-child relationship when cancelling subtasks

This commit fixes an issue where subtasks weren't properly reporting back to parent tasks when cancelled and resumed. Previously, when a subtask was cancelled and a new task was started with the same message, the parent task would incorrectly resume, causing unexpected behavior.

The fix:
1. Stores parent-child relationship information before cancelling a task
2. Restores this relationship after task reinitialization
3. Ensures parent tasks only resume when explicitly instructed to do so

This approach maintains the correct task hierarchy throughout the cancellation and resumption process, preventing parent tasks from automatically resuming when unrelated tasks with similar messages are started.

Author: cannuri

e2e/src/suite/task.test.ts

@@ -1,4 +1,5 @@
 import * as assert from "assert"
+import * as vscode from "vscode"
 
 suite("Roo Code Task", () => {
 	test("Should handle prompt and response correctly", async function () {
@@ -48,4 +49,113 @@ suite("Roo Code Task", () => {
 			"Did not receive expected response containing 'My name is Roo'",
 		)
 	})
+
+	test("Should handle subtask cancellation and resumption correctly", async function () {
+		this.timeout(60000) // Increase timeout for this test
+		const interval = 1000
+
+		if (!globalThis.extension) {
+			assert.fail("Extension not found")
+		}
+
+		// Ensure the webview is launched
+		await ensureWebviewLaunched(30000, interval)
+
+		// Set up required global state
+		await globalThis.provider.updateGlobalState("mode", "Code")
+		await globalThis.provider.updateGlobalState("alwaysAllowModeSwitch", true)
+		await globalThis.provider.updateGlobalState("alwaysAllowSubtasks", true)
+		await globalThis.provider.updateGlobalState("autoApprovalEnabled", true)
+
+		// 1. Start a parent task that will create a subtask
+		await globalThis.api.startNewTask(
+			"You are the parent task. Create a subtask by using the new_task tool with the message 'You are the subtask'. " +
+				"After creating the subtask, wait for it to complete and then respond with 'Parent task resumed'.",
+		)
+
+		// Wait for the parent task to use the new_task tool
+		await waitForToolUse("new_task", 30000, interval)
+
+		// Wait for the subtask to be created and start responding
+		await waitForMessage("You are the subtask", 10000, interval)
+
+		// 3. Cancel the current task (which should be the subtask)
+		await globalThis.provider.cancelTask()
+
+		// 4. Check if the parent task is still waiting (not resumed)
+		// We need to wait a bit to ensure any task resumption would have happened
+		await new Promise((resolve) => setTimeout(resolve, 5000))
+
+		// The parent task should not have resumed yet, so we shouldn't see "Parent task resumed"
+		assert.ok(
+			!globalThis.provider.messages.some(
+				({ type, text }) => type === "say" && text?.includes("Parent task resumed"),
+			),
+			"Parent task should not have resumed after subtask cancellation",
+		)
+
+		// 5. Start a new task with the same message as the subtask
+		await globalThis.api.startNewTask("You are the subtask")
+
+		// Wait for the subtask to complete
+		await waitForMessage("Task complete", 20000, interval)
+
+		// 6. Verify that the parent task is still not resumed
+		// We need to wait a bit to ensure any task resumption would have happened
+		await new Promise((resolve) => setTimeout(resolve, 5000))
+
+		// The parent task should still not have resumed
+		assert.ok(
+			!globalThis.provider.messages.some(
+				({ type, text }) => type === "say" && text?.includes("Parent task resumed"),
+			),
+			"Parent task should not have resumed after subtask completion",
+		)
+
+		// Clean up - cancel all tasks
+		await globalThis.provider.cancelTask()
+	})
 })
+
+// Helper functions
+async function ensureWebviewLaunched(timeout: number, interval: number): Promise<void> {
+	const startTime = Date.now()
+	while (Date.now() - startTime < timeout) {
+		if (globalThis.provider.viewLaunched) {
+			return
+		}
+		await new Promise((resolve) => setTimeout(resolve, interval))
+	}
+	throw new Error("Webview failed to launch within timeout")
+}
+
+async function waitForToolUse(toolName: string, timeout: number, interval: number): Promise<void> {
+	const startTime = Date.now()
+	while (Date.now() - startTime < timeout) {
+		const messages = globalThis.provider.messages
+		if (
+			messages.some(
+				(message) =>
+					message.type === "say" && message.say === "tool" && message.text && message.text.includes(toolName),
+			)
+		) {
+			return
+		}
+		await new Promise((resolve) => setTimeout(resolve, interval))
+	}
+	throw new Error(`Tool ${toolName} was not used within timeout`)
+}
+
+async function waitForMessage(messageContent: string, timeout: number, interval: number): Promise<void> {
+	const startTime = Date.now()
+	while (Date.now() - startTime < timeout) {
+		const messages = globalThis.provider.messages
+		if (
+			messages.some((message) => message.type === "say" && message.text && message.text.includes(messageContent))
+		) {
+			return
+		}
+		await new Promise((resolve) => setTimeout(resolve, interval))
+	}
+	throw new Error(`Message containing "${messageContent}" not found within timeout`)
+}

src/core/webview/ClineProvider.ts

@@ -1933,8 +1933,16 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 
 	async cancelTask() {
 		if (this.getCurrentCline()) {
-			const { historyItem } = await this.getTaskWithId(this.getCurrentCline()!.taskId)
-			this.getCurrentCline()!.abortTask()
+			const currentCline = this.getCurrentCline()!
+			const { historyItem } = await this.getTaskWithId(currentCline.taskId)
+
+			// Store parent task information if this is a subtask
+			// Check if this is a subtask by seeing if it has a parent task
+			const parentTask = currentCline.getParentTask()
+			const isSubTask = parentTask !== undefined
+			const rootTask = isSubTask ? currentCline.getRootTask() : undefined
+
+			currentCline.abortTask()
 
 			await pWaitFor(
 				() =>
@@ -1961,6 +1969,18 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 
 			// Clears task again, so we need to abortTask manually above.
 			await this.initClineWithHistoryItem(historyItem)
+
+			// Restore parent-child relationship if this was a subtask
+			if (isSubTask && this.getCurrentCline() && parentTask) {
+				this.getCurrentCline()!.setSubTask()
+				this.getCurrentCline()!.setParentTask(parentTask)
+				if (rootTask) {
+					this.getCurrentCline()!.setRootTask(rootTask)
+				}
+				this.log(
+					`[subtasks] Restored parent-child relationship for task: ${this.getCurrentCline()!.getTaskNumber()}`,
+				)
+			}
 		}
 	}