Use an enum for direction. (#14927)

For better type safety we  use an enum instead of strings to
configure direction (backwards or forwards).

1 files changed, 14 insertions, 2 deletions

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

index 8c2260ad7d..191529bd8e 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -15,7 +15,13 @@
 import logging
 from typing import TYPE_CHECKING, List, Optional, Tuple, cast
 
-from synapse.api.constants import AccountDataTypes, EduTypes, EventTypes, Membership
+from synapse.api.constants import (
+    AccountDataTypes,
+    Direction,
+    EduTypes,
+    EventTypes,
+    Membership,
+)
 from synapse.api.errors import SynapseError
 from synapse.events import EventBase
 from synapse.events.utils import SerializeEventConfig
@@ -57,7 +63,13 @@ class InitialSyncHandler:
         self.validator = EventValidator()
         self.snapshot_cache: ResponseCache[
             Tuple[
-                str, Optional[StreamToken], Optional[StreamToken], str, int, bool, bool
+                str,
+                Optional[StreamToken],
+                Optional[StreamToken],
+                Direction,
+                int,
+                bool,
+                bool,
             ]
         ] = ResponseCache(hs.get_clock(), "initial_sync_cache")
         self._event_serializer = hs.get_event_client_serializer()