Fixed method Client.get_media_group (pyrogram#619)

Danipulok · delivrance · web-flow · commit ecd83c594cc7 · 2021-05-09T12:43:23.000+02:00
* Fixed method

* Added exception in case message_id is invalid

Co-authored-by: Dan &lt;14043624+delivrance@users.noreply.github.com&gt;
diff --git a/pyrogram/methods/messages/get_media_group.py b/pyrogram/methods/messages/get_media_group.py
@@ -46,13 +46,27 @@ async def get_media_group(
             List of :obj:`~pyrogram.types.Message`: On success, a list of messages of the media group is returned.
             
         Raises:
-            ValueError: In case the passed message id doesn't belong to a media group.
+            ValueError: 
+                In case the passed message_id is negative or equal 0. 
+                In case target message doesn't belong to a media group.
         """
+        
         # There can be maximum 10 items in a media group. 
         messages = await self.get_messages(chat_id, [msg_id for msg_id in range(message_id - 9, message_id + 10)],
                                            replies=0)
 
-        media_group_id = messages[9].media_group_id
+        if message_id <= 0:
+            raise ValueError("Passed message_id is negative or equal to zero.")
+
+        messages = await self.get_messages(
+            chat_id=chat_id,
+            message_ids=[msg_id for msg_id in range(message_id - 9, message_id + 10)],
+            replies=0
+        )
+
+        # There can be maximum 10 items in a media group.
+        # The if/else condition to fix the problem of getting correct `media_group_id` when it has `message_id` less then 10.
+        media_group_id = messages[9].media_group_id if len(messages) == 19 else messages[message_id-1].media_group_id
 
         if media_group_id is None:
             raise ValueError("The message doesn't belong to a media group")
