fix: prevent pending task deletion races with edit flush

Race 1: confirmDeletePendingTask called setEditingQueuedMessageId(null)
before removeThreadOutboxMessage resolved, allowing the outbox drain to
send the message during async removal. Fix: defer clearing the editing
lock until removal completes.

Race 2: confirmDeletePendingTask did not clear editingPendingTaskRef, so
the editor's unmount flush (cancelEditingPendingTask) could re-enqueue
the task via enqueueThreadOutboxMessage before the serialized removal
updated atom state. Fix: track pending deletions in a shared Set so the
flush bails out when a deletion is in progress.

Author: cursoragent

apps/mobile/src/features/home/usePendingTaskListActions.ts

@@ -2,7 +2,11 @@ import { useNavigation } from "@react-navigation/native";
 import { useCallback } from "react";
 import { Alert } from "react-native";
 
-import { removeThreadOutboxMessage } from "../../state/thread-outbox";
+import {
+  clearPendingDeletion,
+  markPendingDeletion,
+  removeThreadOutboxMessage,
+} from "../../state/thread-outbox";
 import type { PendingNewTask } from "../../state/use-pending-new-tasks";
 import { setEditingQueuedMessageId } from "../../state/use-thread-outbox";
 
@@ -36,13 +40,18 @@ export function usePendingTaskListActions(): {
           text: "Delete",
           style: "destructive",
           onPress: () => {
-            setEditingQueuedMessageId(null);
-            void removeThreadOutboxMessage(pendingTask.message).catch((error) => {
-              Alert.alert(
-                "Could not delete pending task",
-                error instanceof Error ? error.message : "The pending task could not be removed.",
-              );
-            });
+            markPendingDeletion(pendingTask.message.messageId);
+            void removeThreadOutboxMessage(pendingTask.message)
+              .catch((error) => {
+                Alert.alert(
+                  "Could not delete pending task",
+                  error instanceof Error ? error.message : "The pending task could not be removed.",
+                );
+              })
+              .finally(() => {
+                clearPendingDeletion(pendingTask.message.messageId);
+                setEditingQueuedMessageId(null);
+              });
           },
         },
       ],

apps/mobile/src/features/threads/new-task-flow-provider.tsx

@@ -41,6 +41,7 @@ import { useBranches } from "../../state/queries";
 import {
   enqueueThreadOutboxMessage,
   flattenQueuedThreadMessages,
+  isPendingDeletion,
   threadOutboxManager,
   type QueuedThreadMessage,
 } from "../../state/thread-outbox";
@@ -616,6 +617,13 @@ export function NewTaskFlowProvider(props: React.PropsWithChildren) {
       editingPendingTaskRef.current = null;
       setEditingPendingTask(null);
 
+      // If a deletion is in progress, bail out and let the delete handler
+      // manage the editing lock and cleanup.
+      if (isPendingDeletion(editing.messageId)) {
+        clearComposerDraft(pendingTaskDraftKey(editing.messageId));
+        return;
+      }
+
       // If the task was deleted externally, skip re-enqueuing.
       const stillQueued = findQueuedPendingTask(editing.messageId);
 

apps/mobile/src/state/thread-outbox.ts

@@ -27,3 +27,17 @@ export function removeThreadOutboxMessage(message: QueuedThreadMessage): Promise
 export function clearThreadOutboxEnvironment(environmentId: EnvironmentId): Promise<void> {
   return threadOutboxManager.clearEnvironment(environmentId);
 }
+
+const pendingDeletionMessageIds = new Set<string>();
+
+export function markPendingDeletion(messageId: string): void {
+  pendingDeletionMessageIds.add(messageId);
+}
+
+export function clearPendingDeletion(messageId: string): void {
+  pendingDeletionMessageIds.delete(messageId);
+}
+
+export function isPendingDeletion(messageId: string): boolean {
+  return pendingDeletionMessageIds.has(messageId);
+}