Fix wrong Message.forward_from with signed channel posts

Before this commit, Message.forward_from returned the user who signed
the post with signed channel posts instead of the channel. This wrong
behavior is now fixed.

Fixes: GH-80

Author: pietroalbini

botogram/objects/messages.py

@@ -387,12 +387,13 @@ def __init__(self, data, api=None):
     def forward_from(self):
         """Get from where the message was forwarded"""
         # Provide either _forward_from or _forward_from_chat
-        if self._forward_from is not None:
-            return self._forward_from
-
+        # _forward_from_chat is checked earlier because it's more correct
         if self._forward_from_chat is not None:
             return self._forward_from_chat
 
+        if self._forward_from is not None:
+            return self._forward_from
+
     @property
     @utils.deprecated("Message.new_chat_participant", "1.0",
                       "Rename property to Message.new_chat_member")

docs/changelog/0.4.rst

@@ -70,6 +70,11 @@ Bug fixes
 
 * Fix inability to fetch updates and stop the runner after an internet
   connection outage.
+* Fix :py:attr:`botogram.Message.forward_from` giving wrong information with
+  signed channel posts (`issue 80`_)
+
+.. _issue 80: https://github.com/pietroalbini/botogram/issues/80
+
 
 Deprecated features
 -------------------