[BUG] Parent task orphaned after clearing/navigating away from delegated child task

[0xMink]

Problem (one or two sentences)

Summary

There are user-triggerable paths where returning to a parent task after delegation fails because the active child task is popped via removeClineFromStack() without any delegation-aware unwind semantics. This can leave the parent task orphaned in a delegated state with awaitingChildId still set, and the user ends up with an empty chat and no way to recover the parent task without manual history repair.

Why this matters

These are normal UI actions, not edge-case runtime failures. A user who clears a delegated child task will see an empty chat with no way to recover the parent task. The system is left in an unrecoverable delegation state without manual history repair.

Suggested direction (minimal)

A delegation-aware unwind chokepoint would allow consistent semantics whenever the active task is popped, rather than relying on each caller of removeClineFromStack() to implement delegation return or repair. No architectural sermon, no 600-line refactor — just a crisp invariant that needs holding. If maintainers want a PR, happy to discuss.

Context (who is affected and when)

Any user who triggers a UI action (Clear Task, navigate to history, or start a new task) while a delegated child task is active.

Reproduction steps

Start a parent task that delegates to a child task
While the child task is active, click "Clear Task"
Observe: child is removed, parent remains in delegated state, user sees empty chat with no way to recover parent task

Expected result

Parent task is restored or delegation is explicitly resolved/cancelled. UI remains in a valid active task state.

Actual result

removeClineFromStack() pops the child without restoring the parent's delegation state. Parent is left orphaned in delegated with stale awaitingChildId, user sees an empty chat with no recovery path.

Variations tried (optional)

Same orphaning occurs via two additional paths:

Navigate to a different task from history while child is active (showTaskWithId → createTaskWithHistoryItem → removeClineFromStack())
Start a new top-level task while child is running (createTask → removeClineFromStack())

App Version

v3.47.3

API Provider (optional)

None

Model Used (optional)

N/A

Roo Code Task Links (optional)

No response

Relevant logs or errors (optional)

[roomote]

I've analyzed this issue and here's my proposed implementation plan:

Root Cause

removeClineFromStack() (ClineProvider.ts:456) is a pure pop-and-dispose operation with no delegation awareness. When a delegated child task is the active (top-of-stack) task, any of these user actions calls removeClineFromStack() without cleaning up the parent's delegation metadata:

1. Clear Task (clearTask() at line 3018)
2. Navigate to history (createTaskWithHistoryItem() at line 880)
3. Start new top-level task (createTask() at line 2908)

The parent's HistoryItem remains stuck with status: "delegated" and awaitingChildId pointing at a child that no longer exists, leaving the user with an empty chat and no recovery path.

Proposed Fix

Make removeClineFromStack() the delegation-aware chokepoint, exactly as the issue author suggests. After popping and disposing the child task, add a metadata cleanup step:

1. Check if the popped task has a parentTaskId (i.e., it was a delegated child)
2. If so, look up the parent's HistoryItem via getTaskWithId(parentTaskId)
3. If the parent has status === "delegated" and awaitingChildId === poppedTask.taskId, update the parent metadata:
   • Set status back to "active"
   • Clear awaitingChildId (set to undefined)
   • Persist via updateTaskHistory()

This is a lightweight metadata repair, not a full delegation return -- no auto-resume of the parent, no subtask_result injection, no API history manipulation. The parent simply becomes resumable from the task history list. The full reopenParentFromDelegation() flow is only needed when a child completes normally via attempt_completion.

Files Changed

• src/core/webview/ClineProvider.ts -- modify removeClineFromStack() to add the parent metadata cleanup after the task is popped. Wrap in try/catch so failures are non-fatal (logged but do not break the existing pop flow).
• Test file(s) -- add tests verifying:
  • When a delegated child is removed, the parent's status transitions from "delegated" to "active" and awaitingChildId is cleared
  • When a non-delegated task is removed, no metadata changes occur
  • Errors during parent lookup are caught and do not prevent the child from being removed

Why This Approach

• Single chokepoint: All three affected paths (and any future callers) go through removeClineFromStack(), so fixing it once covers everything
• Minimal surface area: ~15-20 lines of new code in one method, no architectural changes
• Non-breaking: Wrapped in try/catch, so existing behavior is preserved even if the metadata update fails
• Matches the existing pattern: The codebase already uses getTaskWithId() + updateTaskHistory() for delegation metadata in delegateParentAndOpenChild() and reopenParentFromDelegation()

Please mention @roomote in a comment saying that you approve this plan, and I'll proceed with the implementation.

[0xMink]

@roomote Approved. This is the correct minimal fix: make removeClineFromStack() delegation-aware and repair only parent metadata (status -> active, clear awaitingChildId) when the popped task is a delegated child and awaitingChildId matches the popped child id.

Implementation note: capture parentTaskId (and childTaskId) before abort/dispose, since abortTask(true) is async and the task reference is cleared later.

Please wrap parent lookup + updateTaskHistory in try/catch and treat failures as non-fatal (log, but do not block pop). Tests proposed in your plan sound right.

[roomote]

I've seen the approval and will start implementing the fix now. I'll open a draft PR shortly to share progress.

[roomote]

Opened PR #11302 with my attempt at addressing this. The fix makes removeClineFromStack() delegation-aware by repairing parent metadata (status -> active, clear awaitingChildId) when a delegated child is popped, wrapped in try/catch so failures are non-fatal. Includes 6 new tests covering the happy path, edge cases, and error handling. Feedback welcome!