fix: interrupt error

backend/main.py

@@ -246,6 +246,7 @@ async def nanobot_chat(request: ChatRequest):
 @app.post("/nanobot/chat/stream")
 async def nanobot_chat_stream(request: ChatRequest):
     async def event_generator():
+        current_task = None
         try:
             use_nl2sql, route_reason, resolved_source = _should_use_nl2sql(request)
             yield f"data: {json.dumps({'type': 'routing', 'selected': 'sql' if use_nl2sql else 'chat', 'reason': route_reason}, ensure_ascii=False)}\n\n"
@@ -257,7 +258,7 @@ async def nanobot_chat_stream(request: ChatRequest):
                     if content:
                         await sql_progress_queue.put(content)
 
-                sql_task = asyncio.create_task(
+                current_task = asyncio.create_task(
                     process_nl2sql(
                         NL2SQLRequest(
                             query=request.message,
@@ -269,14 +270,14 @@ async def nanobot_chat_stream(request: ChatRequest):
                     )
                 )
                 while True:
-                    if sql_task.done() and sql_progress_queue.empty():
+                    if current_task.done() and sql_progress_queue.empty():
                         break
                     try:
                         progress = await asyncio.wait_for(sql_progress_queue.get(), timeout=0.2)
                         yield f"data: {json.dumps({'type': 'progress', 'content': progress}, ensure_ascii=False)}\n\n"
                     except asyncio.TimeoutError:
                         continue
-                nl2sql_result = await sql_task
+                nl2sql_result = await current_task
                 if nl2sql_result.error:
                     yield f"data: {json.dumps({'type': 'progress', 'content': f'出错：{nl2sql_result.error}，正在整理结果'}, ensure_ascii=False)}\n\n"
                 else:
@@ -298,7 +299,7 @@ async def nanobot_chat_stream(request: ChatRequest):
                 if content:
                     await progress_queue.put(content)
 
-            task = asyncio.create_task(
+            current_task = asyncio.create_task(
                 nanobot_service.process_message(
                     request.message,
                     session_id=request.session_id,
@@ -310,23 +311,28 @@ async def nanobot_chat_stream(request: ChatRequest):
             yield f"data: {json.dumps({'type': 'progress', 'content': '已发送给模型，正在分析问题'}, ensure_ascii=False)}\n\n"
             text = ""
             while True:
-                if task.done() and progress_queue.empty():
+                if current_task.done() and progress_queue.empty():
                     break
                 try:
                     progress = await asyncio.wait_for(progress_queue.get(), timeout=0.2)
                     yield f"data: {json.dumps({'type': 'progress', 'content': progress}, ensure_ascii=False)}\n\n"
                 except asyncio.TimeoutError:
                     continue
-            response = await task
+            response = await current_task
             text = response or ""
             for idx in range(0, len(text), STREAM_DELTA_CHUNK_SIZE):
                 chunk = text[idx: idx + STREAM_DELTA_CHUNK_SIZE]
                 yield f"data: {json.dumps({'type': 'delta', 'content': chunk}, ensure_ascii=False)}\n\n"
             yield f"data: {json.dumps({'type': 'final', 'content': text}, ensure_ascii=False)}\n\n"
             yield f"data: {json.dumps({'type': 'done'}, ensure_ascii=False)}\n\n"
+        except asyncio.CancelledError:
+            raise
         except Exception as e:
             yield f"data: {json.dumps({'type': 'error', 'content': str(e)}, ensure_ascii=False)}\n\n"
             yield f"data: {json.dumps({'type': 'done'}, ensure_ascii=False)}\n\n"
+        finally:
+            if current_task and not current_task.done():
+                current_task.cancel()
 
     return StreamingResponse(
         event_generator(),