Refactor get_recent_events_for_room return type

There is no reason to return a tuple of tokens when the last token is
always the token passed as an argument. Changing it makes it consistent
with other storage APIs

synapse/handlers/initial_sync.py

@@ -181,8 +181,8 @@ class InitialSyncHandler(BaseHandler):
                     self.store, user_id, messages
                 )
 
-                start_token = now_token.copy_and_replace("room_key", token[0])
+                start_token = now_token.copy_and_replace("room_key", token)
-                end_token = now_token.copy_and_replace("room_key", token[1])
+                end_token = now_token.copy_and_replace("room_key", room_end_token)
                 time_now = self.clock.time_msec()
 
                 d["messages"] = {
@@ -325,8 +325,8 @@ class InitialSyncHandler(BaseHandler):
             self.store, user_id, messages, is_peeking=is_peeking
         )
 
-        start_token = StreamToken.START.copy_and_replace("room_key", token[0])
+        start_token = StreamToken.START.copy_and_replace("room_key", token)
-        end_token = StreamToken.START.copy_and_replace("room_key", token[1])
+        end_token = StreamToken.START.copy_and_replace("room_key", stream_token)
 
         time_now = self.clock.time_msec()
 
@@ -409,7 +409,7 @@ class InitialSyncHandler(BaseHandler):
         )
 
         start_token = now_token.copy_and_replace("room_key", token[0])
-        end_token = now_token.copy_and_replace("room_key", token[1])
+        end_token = now_token
 
         time_now = self.clock.time_msec()
 

synapse/handlers/sync.py

@@ -429,7 +429,7 @@ class SyncHandler(object):
         Returns:
             A Deferred map from ((type, state_key)->Event)
         """
-        last_events, token = yield self.store.get_recent_events_for_room(
+        last_events, _ = yield self.store.get_recent_events_for_room(
             room_id, end_token=stream_position.room_key, limit=1,
         )
 

synapse/storage/stream.py

@@ -359,6 +359,20 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
     @defer.inlineCallbacks
     def get_recent_events_for_room(self, room_id, limit, end_token):
+        """Get the most recent events in the room in topological ordering.
+
+        Args:
+            room_id (str)
+            limit (int)
+            end_token (str): The stream token representing now.
+
+        Returns:
+            Deferred[tuple[list[FrozenEvent],  str]]: Returns a list of
+            events and a token pointint to the start of the returned
+            events.
+            The events returned are in ascending order.
+        """
+
         rows, token = yield self.get_recent_event_ids_for_room(
             room_id, limit, end_token,
         )
@@ -372,7 +386,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         self._set_before_and_after(events, rows)
 
-        defer.returnValue((events, (token, end_token)))
+        defer.returnValue((events, token))
 
     @defer.inlineCallbacks
     def get_recent_event_ids_for_room(self, room_id, limit, end_token):