Simplify internal metadata class. (#16762)

We remove these fields as they're just duplicating data the event
already stores, and (for reasons :shushing_face:) I'd like to simplify
the class to only store simple types.

I'm not entirely convinced that we shouldn't instead add helper methods
to the event class to generate stream tokens, but I don't really think
that's where they belong either

1 files changed, 8 insertions, 2 deletions

diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py

index 1152c0158f..0385c04bc2 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -601,7 +601,10 @@ class SyncHandler:
             if not limited or block_all_timeline:
                 prev_batch_token = upto_token
                 if recents:
-                    room_key = recents[0].internal_metadata.before
+                    assert recents[0].internal_metadata.stream_ordering
+                    room_key = RoomStreamToken(
+                        stream=recents[0].internal_metadata.stream_ordering - 1
+                    )
                     prev_batch_token = upto_token.copy_and_replace(
                         StreamKeyType.ROOM, room_key
                     )
@@ -689,7 +692,10 @@ class SyncHandler:
             if len(recents) > timeline_limit:
                 limited = True
                 recents = recents[-timeline_limit:]
-                room_key = recents[0].internal_metadata.before
+                assert recents[0].internal_metadata.stream_ordering
+                room_key = RoomStreamToken(
+                    stream=recents[0].internal_metadata.stream_ordering - 1
+                )
 
             prev_batch_token = upto_token.copy_and_replace(StreamKeyType.ROOM, room_key)