Merge pull request #24 from dxFeed/EN-1818-fields-reordering-warning

[EN-1818] vanilla warning

Author: Aleksandr Salynskii

dxfeed/core/DXFeedPy.pyx

@@ -305,6 +305,9 @@ def dxf_attach_listener(SubscriptionClass sc):
     event_handler = sc.get_event_handler()
     if not event_handler:
         raise ValueError('Event handler is not defined!')
+    warn('New order in event fields will be introduced in dxfeed-0.6.0. Please, address event fields '
+         'by name in custom event handler.',
+         FutureWarning)
 
     if sc.event_type_str == 'Trade':
         event_handler.columns = lis.TRADE_COLUMNS

dxfeed/wrappers/subscription.py

@@ -1,7 +1,9 @@
-from dxfeed.core import DXFeedPy as dxp
-from dxfeed.core.utils.handler import DefaultHandler
 from typing import Iterable, Union, Optional
 from datetime import datetime
+from warnings import simplefilter
+
+from dxfeed.core import DXFeedPy as dxp
+from dxfeed.core.utils.handler import DefaultHandler
 import dxfeed.wrappers.class_utils as cu
 
 
@@ -114,7 +116,12 @@ def _attach_default_listener(self):
         """
         if not self.get_event_handler():
             self.set_event_handler(DefaultHandler())
+            simplefilter(action='ignore', category=FutureWarning)
+
         dxp.dxf_attach_listener(self.__sub)
+
+        simplefilter(action='default', category=FutureWarning)
+
         return self
 
     def _detach_listener(self):