fix: 修改一下生图的 bug

server/services/jobs.py

@@ -206,11 +206,26 @@ async def claim_next_item(owner: str, lease_seconds: int = 90) -> ClaimedItem |
 
 
 async def mark_waiting_provider(item_id: str, provider_task_id: str, provider_task_kind: str, delay_seconds: int = 3) -> None:
-    """先持久化外部任务 ID，再安排下一次查询，是避免重启重复扣费的关键提交点。"""
+    """持久化外部任务 ID 并安排下一次查询。
+
+    取消可能恰好发生在 Worker 轮询供应商的网络请求期间。这里在同一事务内
+    再次检查父任务，避免已取消任务被写回 waiting_provider 后永远不再被领取。
+    """
     async with get_session_factory()() as db:
         item = await db.get(BackgroundJobItem, uuid.UUID(item_id))
         if item is None:
             return
+        job = await db.get(BackgroundJob, item.job_id)
+        if job is None or job.cancel_requested:
+            item.status = ITEM_CANCELLED
+            item.lease_owner = None
+            item.lease_expires_at = None
+            item.next_run_at = None
+            item.completed_at = utcnow()
+            if job is not None:
+                await _refresh_job_status(db, job)
+            await db.commit()
+            return
         item.provider_task_id = provider_task_id
         item.provider_task_kind = provider_task_kind
         item.status = ITEM_WAITING_PROVIDER