fix: make removeClineFromStack() delegation-aware to prevent orphaned parent tasks (#11302)

* fix: make removeClineFromStack() delegation-aware to prevent orphaned parent tasks

When a delegated child task is removed via removeClineFromStack() (e.g., Clear
Task, navigate to history, start new task), the parent task was left orphaned
in "delegated" status with a stale awaitingChildId. This made the parent
unresumable without manual history repair.

This fix captures parentTaskId and childTaskId before abort/dispose, then
repairs the parent metadata (status -> active, clear awaitingChildId) when
the popped task is a delegated child and awaitingChildId matches.

Parent lookup + updateTaskHistory are wrapped in try/catch so failures are
non-fatal (logged but do not block the pop).

Closes #11301

* fix: add skipDelegationRepair opt-out to removeClineFromStack() for nested delegation

---------

Co-authored-by: Roo Code <roomote@roocode.com>

src/__tests__/removeClineFromStack-delegation.spec.ts

@@ -0,0 +1,281 @@
+// npx vitest run __tests__/removeClineFromStack-delegation.spec.ts
+
+import { describe, it, expect, vi } from "vitest"
+import { ClineProvider } from "../core/webview/ClineProvider"
+
+describe("ClineProvider.removeClineFromStack() delegation awareness", () => {
+	/**
+	 * Helper to build a minimal mock provider with a single task on the stack.
+	 * The task's parentTaskId and taskId are configurable.
+	 */
+	function buildMockProvider(opts: {
+		childTaskId: string
+		parentTaskId?: string
+		parentHistoryItem?: Record<string, any>
+		getTaskWithIdError?: Error
+	}) {
+		const childTask = {
+			taskId: opts.childTaskId,
+			instanceId: "inst-1",
+			parentTaskId: opts.parentTaskId,
+			emit: vi.fn(),
+			abortTask: vi.fn().mockResolvedValue(undefined),
+		}
+
+		const updateTaskHistory = vi.fn().mockResolvedValue([])
+		const getTaskWithId = opts.getTaskWithIdError
+			? vi.fn().mockRejectedValue(opts.getTaskWithIdError)
+			: vi.fn().mockImplementation(async (id: string) => {
+					if (id === opts.parentTaskId && opts.parentHistoryItem) {
+						return { historyItem: { ...opts.parentHistoryItem } }
+					}
+					throw new Error("Task not found")
+				})
+
+		const provider = {
+			clineStack: [childTask] as any[],
+			taskEventListeners: new Map(),
+			log: vi.fn(),
+			getTaskWithId,
+			updateTaskHistory,
+		}
+
+		return { provider, childTask, updateTaskHistory, getTaskWithId }
+	}
+
+	it("repairs parent metadata (delegated → active) when a delegated child is removed", async () => {
+		const { provider, updateTaskHistory, getTaskWithId } = buildMockProvider({
+			childTaskId: "child-1",
+			parentTaskId: "parent-1",
+			parentHistoryItem: {
+				id: "parent-1",
+				task: "Parent task",
+				ts: 1000,
+				number: 1,
+				tokensIn: 0,
+				tokensOut: 0,
+				totalCost: 0,
+				status: "delegated",
+				awaitingChildId: "child-1",
+				delegatedToId: "child-1",
+				childIds: ["child-1"],
+			},
+		})
+
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider)
+
+		// Stack should be empty after pop
+		expect(provider.clineStack).toHaveLength(0)
+
+		// Parent lookup should have been called
+		expect(getTaskWithId).toHaveBeenCalledWith("parent-1")
+
+		// Parent metadata should be repaired
+		expect(updateTaskHistory).toHaveBeenCalledTimes(1)
+		const updatedParent = updateTaskHistory.mock.calls[0][0]
+		expect(updatedParent).toEqual(
+			expect.objectContaining({
+				id: "parent-1",
+				status: "active",
+				awaitingChildId: undefined,
+			}),
+		)
+
+		// Log the repair
+		expect(provider.log).toHaveBeenCalledWith(expect.stringContaining("Repaired parent parent-1 metadata"))
+	})
+
+	it("does NOT modify parent metadata when the task has no parentTaskId (non-delegated)", async () => {
+		const { provider, updateTaskHistory, getTaskWithId } = buildMockProvider({
+			childTaskId: "standalone-1",
+			// No parentTaskId — this is a top-level task
+		})
+
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider)
+
+		// Stack should be empty
+		expect(provider.clineStack).toHaveLength(0)
+
+		// No parent lookup or update should happen
+		expect(getTaskWithId).not.toHaveBeenCalled()
+		expect(updateTaskHistory).not.toHaveBeenCalled()
+	})
+
+	it("does NOT modify parent metadata when awaitingChildId does not match the popped child", async () => {
+		const { provider, updateTaskHistory, getTaskWithId } = buildMockProvider({
+			childTaskId: "child-1",
+			parentTaskId: "parent-1",
+			parentHistoryItem: {
+				id: "parent-1",
+				task: "Parent task",
+				ts: 1000,
+				number: 1,
+				tokensIn: 0,
+				tokensOut: 0,
+				totalCost: 0,
+				status: "delegated",
+				awaitingChildId: "child-OTHER", // different child
+				delegatedToId: "child-OTHER",
+				childIds: ["child-OTHER"],
+			},
+		})
+
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider)
+
+		// Parent was looked up but should NOT be updated
+		expect(getTaskWithId).toHaveBeenCalledWith("parent-1")
+		expect(updateTaskHistory).not.toHaveBeenCalled()
+	})
+
+	it("does NOT modify parent metadata when parent status is not 'delegated'", async () => {
+		const { provider, updateTaskHistory, getTaskWithId } = buildMockProvider({
+			childTaskId: "child-1",
+			parentTaskId: "parent-1",
+			parentHistoryItem: {
+				id: "parent-1",
+				task: "Parent task",
+				ts: 1000,
+				number: 1,
+				tokensIn: 0,
+				tokensOut: 0,
+				totalCost: 0,
+				status: "completed", // already completed
+				awaitingChildId: "child-1",
+				childIds: ["child-1"],
+			},
+		})
+
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider)
+
+		expect(getTaskWithId).toHaveBeenCalledWith("parent-1")
+		expect(updateTaskHistory).not.toHaveBeenCalled()
+	})
+
+	it("catches and logs errors during parent metadata repair without blocking the pop", async () => {
+		const { provider, childTask, updateTaskHistory, getTaskWithId } = buildMockProvider({
+			childTaskId: "child-1",
+			parentTaskId: "parent-1",
+			getTaskWithIdError: new Error("Storage unavailable"),
+		})
+
+		// Should NOT throw
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider)
+
+		// Stack should still be empty (pop was not blocked)
+		expect(provider.clineStack).toHaveLength(0)
+
+		// The abort should still have been called
+		expect(childTask.abortTask).toHaveBeenCalledWith(true)
+
+		// Error should be logged as non-fatal
+		expect(provider.log).toHaveBeenCalledWith(
+			expect.stringContaining("Failed to repair parent metadata for parent-1 (non-fatal)"),
+		)
+
+		// No update should have been attempted
+		expect(updateTaskHistory).not.toHaveBeenCalled()
+	})
+
+	it("handles empty stack gracefully", async () => {
+		const provider = {
+			clineStack: [] as any[],
+			taskEventListeners: new Map(),
+			log: vi.fn(),
+			getTaskWithId: vi.fn(),
+			updateTaskHistory: vi.fn(),
+		}
+
+		// Should not throw
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider)
+
+		expect(provider.clineStack).toHaveLength(0)
+		expect(provider.getTaskWithId).not.toHaveBeenCalled()
+		expect(provider.updateTaskHistory).not.toHaveBeenCalled()
+	})
+
+	it("skips delegation repair when skipDelegationRepair option is true", async () => {
+		const { provider, updateTaskHistory, getTaskWithId } = buildMockProvider({
+			childTaskId: "child-1",
+			parentTaskId: "parent-1",
+			parentHistoryItem: {
+				id: "parent-1",
+				task: "Parent task",
+				ts: 1000,
+				number: 1,
+				tokensIn: 0,
+				tokensOut: 0,
+				totalCost: 0,
+				status: "delegated",
+				awaitingChildId: "child-1",
+				delegatedToId: "child-1",
+				childIds: ["child-1"],
+			},
+		})
+
+		// Call with skipDelegationRepair: true (as delegateParentAndOpenChild would)
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider, { skipDelegationRepair: true })
+
+		// Stack should be empty after pop
+		expect(provider.clineStack).toHaveLength(0)
+
+		// Parent lookup should NOT have been called — repair was skipped entirely
+		expect(getTaskWithId).not.toHaveBeenCalled()
+		expect(updateTaskHistory).not.toHaveBeenCalled()
+	})
+
+	it("does NOT reset grandparent during A→B→C nested delegation transition", async () => {
+		// Scenario: A delegated to B, B is now delegating to C.
+		// delegateParentAndOpenChild() pops B via removeClineFromStack({ skipDelegationRepair: true }).
+		// Grandparent A should remain "delegated" — its metadata must not be repaired.
+		const grandparentHistory = {
+			id: "task-A",
+			task: "Grandparent task",
+			ts: 1000,
+			number: 1,
+			tokensIn: 0,
+			tokensOut: 0,
+			totalCost: 0,
+			status: "delegated",
+			awaitingChildId: "task-B",
+			delegatedToId: "task-B",
+			childIds: ["task-B"],
+		}
+
+		const taskB = {
+			taskId: "task-B",
+			instanceId: "inst-B",
+			parentTaskId: "task-A",
+			emit: vi.fn(),
+			abortTask: vi.fn().mockResolvedValue(undefined),
+		}
+
+		const getTaskWithId = vi.fn().mockImplementation(async (id: string) => {
+			if (id === "task-A") {
+				return { historyItem: { ...grandparentHistory } }
+			}
+			throw new Error("Task not found")
+		})
+		const updateTaskHistory = vi.fn().mockResolvedValue([])
+
+		const provider = {
+			clineStack: [taskB] as any[],
+			taskEventListeners: new Map(),
+			log: vi.fn(),
+			getTaskWithId,
+			updateTaskHistory,
+		}
+
+		// Simulate what delegateParentAndOpenChild does: pop B with skipDelegationRepair
+		await (ClineProvider.prototype as any).removeClineFromStack.call(provider, { skipDelegationRepair: true })
+
+		// B was popped
+		expect(provider.clineStack).toHaveLength(0)
+
+		// Grandparent A should NOT have been looked up or modified
+		expect(getTaskWithId).not.toHaveBeenCalled()
+		expect(updateTaskHistory).not.toHaveBeenCalled()
+
+		// Grandparent A's metadata remains intact (delegated, awaitingChildId: task-B)
+		// The caller (delegateParentAndOpenChild) will update A to point to C separately.
+	})
+})

src/core/webview/ClineProvider.ts

@@ -456,7 +456,7 @@ export class ClineProvider
 
 	// Removes and destroys the top Cline instance (the current finished task),
 	// activating the previous one (resuming the parent task).
-	async removeClineFromStack() {
+	async removeClineFromStack(options?: { skipDelegationRepair?: boolean }) {
 		if (this.clineStack.length === 0) {
 			return
 		}
@@ -465,6 +465,11 @@ export class ClineProvider
 		let task = this.clineStack.pop()
 
 		if (task) {
+			// Capture delegation metadata before abort/dispose, since abortTask(true)
+			// is async and the task reference is cleared afterwards.
+			const childTaskId = task.taskId
+			const parentTaskId = task.parentTaskId
+
 			task.emit(RooCodeEventName.TaskUnfocused)
 
 			try {
@@ -488,6 +493,37 @@ export class ClineProvider
 			// Make sure no reference kept, once promises end it will be
 			// garbage collected.
 			task = undefined
+
+			// Delegation-aware parent metadata repair:
+			// If the popped task was a delegated child, repair the parent's metadata
+			// so it transitions from "delegated" back to "active" and becomes resumable
+			// from the task history list.
+			// Skip when called from delegateParentAndOpenChild() during nested delegation
+			// transitions (A→B→C), where the caller intentionally replaces the active
+			// child and will update the parent to point at the new child.
+			if (parentTaskId && childTaskId && !options?.skipDelegationRepair) {
+				try {
+					const { historyItem: parentHistory } = await this.getTaskWithId(parentTaskId)
+
+					if (parentHistory.status === "delegated" && parentHistory.awaitingChildId === childTaskId) {
+						await this.updateTaskHistory({
+							...parentHistory,
+							status: "active",
+							awaitingChildId: undefined,
+						})
+						this.log(
+							`[ClineProvider#removeClineFromStack] Repaired parent ${parentTaskId} metadata: delegated → active (child ${childTaskId} removed)`,
+						)
+					}
+				} catch (err) {
+					// Non-fatal: log but do not block the pop operation.
+					this.log(
+						`[ClineProvider#removeClineFromStack] Failed to repair parent metadata for ${parentTaskId} (non-fatal): ${
+							err instanceof Error ? err.message : String(err)
+						}`,
+					)
+				}
+			}
 		}
 	}
 
@@ -3268,7 +3304,7 @@ export class ClineProvider
 		//    This ensures we never have >1 tasks open at any time during delegation.
 		//    Await abort completion to ensure clean disposal and prevent unhandled rejections.
 		try {
-			await this.removeClineFromStack()
+			await this.removeClineFromStack({ skipDelegationRepair: true })
 		} catch (error) {
 			this.log(
 				`[delegateParentAndOpenChild] Error during parent disposal (non-fatal): ${