fix: reset subtasks for recurring tasks

backend/main.py

@@ -640,6 +640,7 @@ async def update_task(
     data = payload.model_dump(exclude_unset=True)
     expected_version = data.pop("version")
     recurrence = None
+    reset_subtasks = False
     if data.get("completed") is True:
         recurrence = await db.scalar(select(RecurrenceTemplate).where(
             RecurrenceTemplate.task_id == task_id, RecurrenceTemplate.user_id == user.id
@@ -656,6 +657,7 @@ async def update_task(
                 data["completed"] = False
                 data["due_at"] = next_items[0]
                 recurrence.starts_at = next_items[0]
+                reset_subtasks = True
     if "list_id" in data:
         await _owned_list(db, user.id, data["list_id"])
         if task.parent_id:
@@ -685,6 +687,18 @@ async def update_task(
         if exists_id:
             raise HTTPException(status_code=409, detail="任务已被更新，请刷新后重试")
         raise HTTPException(status_code=404, detail="任务不存在")
+    if reset_subtasks:
+        reset_at = utcnow()
+        await db.execute(
+            update(Task)
+            .where(
+                Task.parent_id == task.id,
+                Task.user_id == user.id,
+                Task.deleted_at.is_(None),
+                Task.completed.is_(True),
+            )
+            .values(completed=False, version=Task.version + 1, updated_at=reset_at)
+        )
     if "list_id" in data and task.parent_id is None:
         await db.execute(
             update(Task)

tests/test_mvp_backend.py

@@ -134,6 +134,47 @@ def test_completing_repeating_task_advances_due_date_instead_of_closing_it(clien
     assert recurrence["starts_at"].replace("Z", "") == "2026-09-08T09:00:00"
 
 
+def test_completing_repeating_task_resets_completed_subtasks_for_next_occurrence(client):
+    inbox = boot(client)
+    parent = client.post(
+        "/api/v1/tasks",
+        json={
+            "title": "每日清理",
+            "list_id": inbox["id"],
+            "due_at": "2026-09-07T09:00:00Z",
+            "rrule": "FREQ=DAILY",
+        },
+    ).json()
+    first = client.post(
+        "/api/v1/tasks",
+        json={"title": "清理下载", "list_id": inbox["id"], "parent_id": parent["id"]},
+    ).json()
+    second = client.post(
+        "/api/v1/tasks",
+        json={"title": "清理缓存", "list_id": inbox["id"], "parent_id": parent["id"]},
+    ).json()
+    for child in (first, second):
+        response = client.patch(
+            f"/api/v1/tasks/{child['id']}",
+            json={"completed": True, "version": child["version"]},
+        )
+        assert response.status_code == 200
+
+    completed = client.patch(
+        f"/api/v1/tasks/{parent['id']}",
+        json={"completed": True, "version": parent["version"]},
+    )
+
+    assert completed.status_code == 200
+    assert completed.json()["completed"] is False
+    assert completed.json()["due_at"].replace("Z", "") == "2026-09-08T09:00:00"
+    assert [child["completed"] for child in completed.json()["subtasks"]] == [False, False]
+    listed = client.get("/api/v1/tasks", params={"list_id": inbox["id"], "page": 1}).json()["items"]
+    repeated = next(task for task in listed if task["id"] == parent["id"])
+    assert [child["completed"] for child in repeated["subtasks"]] == [False, False]
+
+
+
 def test_recurrence_mutations_keep_exact_timestamp_validation(client):
     inbox = boot(client)
     task = client.post(