feat: Reparent child tasks atomically on parent deletion

When a task is deleted, ensure its child tasks are correctly reparented
to the deleted task's own parent. This change also consolidates
the task history update into a single operation.

This addresses an issue where the UI update for reparenting and
deletion could appear delayed by ensuring all modifications to the
task list are processed together before the UI is refreshed.

Signed-off-by: Eric Wheeler <[email protected]>

Author: Eric Wheeler

src/core/webview/ClineProvider.ts

@@ -1112,8 +1112,29 @@ export class ClineProvider extends EventEmitter<ClineProviderEvents> implements
 	// this function deletes a task from task hidtory, and deletes it's checkpoints and delete the task folder
 	async deleteTaskWithId(id: string) {
 		try {
-			// get the task directory full path
-			const { taskDirPath } = await this.getTaskWithId(id)
+			// Get the task to be deleted to access its parent_task_id
+			const { historyItem: deletedTaskHistoryItem, taskDirPath } = await this.getTaskWithId(id)
+			const grandparentTaskId = deletedTaskHistoryItem.parent_task_id
+
+			let currentTaskHistory = (this.getGlobalState("taskHistory") as HistoryItem[] | undefined) || []
+
+			// Create a new array with reparented children
+			const reparentedTaskHistory = currentTaskHistory.map((task) => {
+				if (task.parent_task_id === id) {
+					this.log(`Reparenting task ${task.id} from ${id} to ${grandparentTaskId ?? "undefined (root)"}`)
+					return { ...task, parent_task_id: grandparentTaskId }
+				}
+				return task
+			})
+
+			// Filter out the deleted task: this is in lieu of `deleteTaskFromState(id)`
+			const finalTaskHistory = reparentedTaskHistory.filter((task) => task.id !== id)
+
+			// Update global state with the final list
+			await this.updateGlobalState("taskHistory", finalTaskHistory)
+
+			// Post the final state to the webview, ensuring UI reflects all changes at once
+			await this.postStateToWebview()
 
 			// remove task from stack if it's the current task
 			if (id === this.getCurrentCline()?.taskId) {
@@ -1122,9 +1143,6 @@ export class ClineProvider extends EventEmitter<ClineProviderEvents> implements
 				await this.finishSubTask(t("common:tasks.deleted"))
 			}
 
-			// delete task from the task history state
-			await this.deleteTaskFromState(id)
-
 			// Delete associated shadow repository or branch.
 			// TODO: Store `workspaceDir` in the `HistoryItem` object.
 			const globalStorageDir = this.contextProxy.globalStorageUri.fsPath