修复状态兼容性问题：让旧节点同时支持 dict 和 dataclass

backend/app/main_graph/nodes/retrieve_memory.py

@@ -11,27 +11,36 @@ from app.memory.mem0_client import Mem0Client
 from app.utils.logging import log_state_change
 from app.logger import debug
 
+
+def _get_attr(state, attr_name, default=None):
+    """通用方法：兼容 dict 和 dataclass 两种状态格式"""
+    if isinstance(state, dict):
+        return state.get(attr_name, default)
+    else:
+        return getattr(state, attr_name, default)
+
+
 def create_retrieve_memory_node(mem0_client: Mem0Client):
     """
     工厂函数：创建记忆检索节点
     
     Args:
         mem0_client: Mem0 客户端实例
-        
+    
     Returns:
         异步节点函数
     """
     
     from langchain_core.runnables.config import RunnableConfig
     
-    async def retrieve_memory(state: MessagesState, config: RunnableConfig) -> Dict[str, Any]:
+    async def retrieve_memory(state, config: RunnableConfig) -> Dict[str, Any]:
         """
         记忆检索节点 - 使用 Mem0
         
         Args:
-            state: 当前对话状态
+            state: 当前对话状态（兼容 dict 和 dataclass）
             config: 运行时配置
-            
+        
         Returns:
             包含 memory_context 的状态更新
         """
@@ -41,11 +50,15 @@ def create_retrieve_memory_node(mem0_client: Mem0Client):
         user_id = config.get("metadata", {}).get("user_id", "default_user")
         
         # 兼容 dict 和对象两种消息格式
-        last_msg = state["messages"][-1]
-        if isinstance(last_msg, dict):
-            query = str(last_msg.get("content", ""))
+        messages = _get_attr(state, "messages", [])
+        last_msg = messages[-1] if messages else None
+        if last_msg:
+            if isinstance(last_msg, dict):
+                query = str(last_msg.get("content", ""))
+            else:
+                query = str(last_msg.content)
         else:
-            query = str(last_msg.content)
+            query = ""
         memory_text_parts = []
 
         # 确保 Mem0 已初始化（懒加载）
@@ -70,7 +83,7 @@ def create_retrieve_memory_node(mem0_client: Mem0Client):
 
         memory_context = "\n\n".join(memory_text_parts) if memory_text_parts else "暂无用户信息"
         result = {"memory_context": memory_context}
-        log_state_change("retrieve_memory", {**state, **result}, "离开")
+        log_state_change("retrieve_memory", {**state, **result} if isinstance(state, dict) else state, "离开")
         return result
     
-    return retrieve_memory
+    return retrieve_memory