diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index c656e07d37..d485f21e49 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -561,8 +561,6 @@ class EventCreationHandler:
expiry_ms=30 * 60 * 1000,
)
- self._msc3970_enabled = hs.config.experimental.msc3970_enabled
-
async def create_event(
self,
requester: Requester,
@@ -897,9 +895,8 @@ class EventCreationHandler:
"""
existing_event_id = None
- if self._msc3970_enabled and requester.device_id:
- # When MSC3970 is enabled, we lookup for events sent by the same device first,
- # and fallback to the old behaviour if none were found.
+ # According to the spec, transactions are scoped to a user's device ID.
+ if requester.device_id:
existing_event_id = (
await self.store.get_event_id_from_transaction_id_and_device_id(
room_id,
@@ -911,8 +908,9 @@ class EventCreationHandler:
if existing_event_id:
return existing_event_id
- # Pre-MSC3970, we looked up for events that were sent by the same session by
- # using the access token ID.
+ # Some requsters don't have device IDs (appservice, guests, and access
+ # tokens minted with the admin API), fallback to checking the access token
+ # ID, which should be close enough.
if requester.access_token_id:
existing_event_id = (
await self.store.get_event_id_from_transaction_id_and_token_id(
|
