Return correct total participant count when a filter is desired

readthedocs/misc/v2-migration-guide.rst

@@ -225,6 +225,16 @@ The "aggressive" hack in ``get_participants`` (and ``iter_participants``) is now
 It was not reliable, and was a cause of flood wait errors.
 
 
+The total value when getting participants has changed
+-----------------------------------------------------
+
+Before, it used to always be the total amount of people inside the chat. Now the filter is also
+considered. If you were running ``client.get_participants`` with a ``filter`` other than the
+default and accessing the ``list.total``, you will now get a different result. You will need to
+perform a separate request with no filter to fetch the total without filter (this is what the
+library used to do).
+
+
 The TelegramClient is no longer made out of mixins
 --------------------------------------------------
 

telethon/_client/chats.py

@@ -184,27 +184,8 @@ class _ParticipantsIter(requestiter.RequestIter):
         if self.request.offset > self.limit:
             return True
 
-        if self.total is None:
-            f = self.request.filter
-            if (
-                not isinstance(f, _tl.ChannelParticipantsRecent)
-                and (not isinstance(f, _tl.ChannelParticipantsSearch) or f.q)
-            ):
-                # Only do an additional getParticipants here to get the total
-                # if there's a filter which would reduce the real total number.
-                # getParticipants is cheaper than getFull.
-                self.total = (await self.client(_tl.fn.channels.GetParticipants(
-                    channel=self.request.channel,
-                    filter=_tl.ChannelParticipantsRecent(),
-                    offset=0,
-                    limit=1,
-                    hash=0
-                ))).count
-
         participants = await self.client(self.request)
-        if self.total is None:
+        self.total = participants.count
-            # Will only get here if there was one request with a filter that matched all users.
-            self.total = participants.count
 
         self.request.offset += len(participants.participants)
         users = {user.id: user for user in participants.users}