Fix /messages on workers when no from param specified.

If no `from` param is specified we calculate and use the "current
token" that inlcuded typing, presence, etc. These are unused during
pagination and are not available on workers, so we simply don't
calculate them.

synapse/handlers/pagination.py

@@ -180,9 +180,7 @@ class PaginationHandler(object):
             room_token = pagin_config.from_token.room_key
         else:
             pagin_config.from_token = (
-                yield self.hs.get_event_sources().get_current_token_for_room(
-                    room_id=room_id
-                )
+                yield self.hs.get_event_sources().get_current_token_for_pagination()
             )
             room_token = pagin_config.from_token.room_key
 

synapse/streams/events.py

@@ -59,21 +59,25 @@ class EventSources(object):
         defer.returnValue(token)
 
     @defer.inlineCallbacks
-    def get_current_token_for_room(self, room_id):
-        push_rules_key, _ = self.store.get_push_rules_stream_token()
-        to_device_key = self.store.get_to_device_stream_token()
-        device_list_key = self.store.get_device_stream_token()
-        groups_key = self.store.get_group_stream_token()
+    def get_current_token_for_pagination(self):
+        """Get the current token for a given room to be used to paginate
+        events.
 
+        The returned token does not have the current values for fields other
+        than `room`, since they are not used during pagination.
+
+        Retuns:
+            Deferred[StreamToken]
+        """
         token = StreamToken(
-            room_key=(yield self.sources["room"].get_current_key_for_room(room_id)),
-            presence_key=(yield self.sources["presence"].get_current_key()),
-            typing_key=(yield self.sources["typing"].get_current_key()),
-            receipt_key=(yield self.sources["receipt"].get_current_key()),
-            account_data_key=(yield self.sources["account_data"].get_current_key()),
-            push_rules_key=push_rules_key,
-            to_device_key=to_device_key,
-            device_list_key=device_list_key,
-            groups_key=groups_key,
+            room_key=(yield self.sources["room"].get_current_key()),
+            presence_key=0,
+            typing_key=0,
+            receipt_key=0,
+            account_data_key=0,
+            push_rules_key=0,
+            to_device_key=0,
+            device_list_key=0,
+            groups_key=0,
         )
         defer.returnValue(token)