fix(warehouse): fix 500 error on delete by extracting attributes before db commit

inventory-backend/app/api/v1/warehouse.py

@@ -171,10 +171,13 @@ def delete_location(location_id):
     """
     try:
         location = SysWarehouseLocation.query.get(location_id)
-        
+
         if not location:
             return jsonify({'code': 404, 'msg': '库位不存在', 'data': None})
-        
+
+        # 在删除前提取属性，避免 commit 后访问已删除对象
+        location_code = location.location_code
+
         # 递归删除所有子库位
         def delete_recursive(loc):
             # 先删除所有子节点
@@ -183,14 +186,14 @@ def delete_location(location_id):
                 delete_recursive(child)
             # 再删除自身
             db.session.delete(loc)
-        
+
         delete_recursive(location)
         db.session.commit()
 
         return jsonify({
             'code': 200,
             'msg': '删除成功',
-            'location_code': location.location_code
+            'location_code': location_code
         })
     except Exception as e:
         db.session.rollback()