From 771692addda05253a423535a704f30afed0fb62f Mon Sep 17 00:00:00 2001
From: Kegan Dougal <7190048+kegsay@users.noreply.github.com>
Date: Wed, 24 Sep 2025 11:45:06 +0100
Subject: [PATCH] Rejig when we persist sticky events

Persist inside persist_events to guarantee it is done. After that txn,
recheck soft failure.
---
 synapse/storage/databases/main/events.py      |  3 ++
 .../storage/databases/main/sticky_events.py   | 37 ++++++++-----------
 2 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 824a77e456..ab9fbc4a1c 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -1186,6 +1186,9 @@ class PersistEventsStore:
                 sliding_sync_table_changes,
             )
 
+        if self.msc4354_sticky_events:
+            self.store.insert_sticky_events_txn(txn, events_and_contexts)
+
         # We only update the sliding sync tables for non-backfilled events.
         self._update_sliding_sync_tables_with_new_persisted_events_txn(
             txn, room_id, events_and_contexts
diff --git a/synapse/storage/databases/main/sticky_events.py b/synapse/storage/databases/main/sticky_events.py
index 80474e229b..e9a45bcf4e 100644
--- a/synapse/storage/databases/main/sticky_events.py
+++ b/synapse/storage/databases/main/sticky_events.py
@@ -57,6 +57,7 @@ logger = logging.getLogger(__name__)
 # Consumers call 'get_sticky_events_in_rooms' which has `WHERE expires_at > ?`
 # to filter out expired sticky events that have yet to be deleted.
 DELETE_EXPIRED_STICKY_EVENTS_MS = 60 * 1000 * 60  # 1 hour
+MAX_STICKY_DURATION_MS = 3600000  # 1 hour
 
 
 class StickyEventsWorkerStore(StateGroupWorkerStore, CacheInvalidationWorkerStore):
@@ -231,16 +232,18 @@ class StickyEventsWorkerStore(StateGroupWorkerStore, CacheInvalidationWorkerStor
             state_delta_for_room: The changes to the current state, used to detect if we need to
             re-evaluate soft-failed sticky events.
         """
-        if len(events_and_contexts) == 0:
-            return
-
         assert self._can_write_to_sticky_events
 
-        # fetch soft failed sticky events to recheck now, before we insert new sticky events, else
-        # we could incorrectly re-evaluate new sticky events in events_and_contexts
+        # fetch soft failed sticky events to recheck
         event_ids_to_check = await self._get_soft_failed_sticky_events_to_recheck(
             room_id, state_delta_for_room
         )
+        # filter out soft-failed events in events_and_contexts as we just inserted them, so the
+        # soft failure status won't have changed for them.
+        persisting_event_ids = {ev.event_id for ev, _ in events_and_contexts}
+        event_ids_to_check = [
+            item for item in event_ids_to_check if item not in persisting_event_ids
+        ]
         if event_ids_to_check:
             logger.info(
                 "_get_soft_failed_sticky_events_to_recheck => %s", event_ids_to_check
@@ -248,18 +251,7 @@ class StickyEventsWorkerStore(StateGroupWorkerStore, CacheInvalidationWorkerStor
             # recheck them and update any that now pass soft-fail checks.
             await self._recheck_soft_failed_events(room_id, event_ids_to_check)
 
-        # insert brand new sticky events.
-        await self._insert_sticky_events(events_and_contexts)
-
-    async def _insert_sticky_events(
-        self,
-        events_and_contexts: List[EventPersistencePair],
-    ) -> None:
-        await self.db_pool.runInteraction(
-            "_insert_sticky_events", self._insert_sticky_events_txn, events_and_contexts
-        )
-
-    def _insert_sticky_events_txn(
+    def insert_sticky_events_txn(
         self,
         txn: LoggingTransaction,
         events_and_contexts: List[EventPersistencePair],
@@ -279,17 +271,18 @@ class StickyEventsWorkerStore(StateGroupWorkerStore, CacheInvalidationWorkerStor
             if type(sticky_obj) is not dict:
                 continue
             sticky_duration_ms = sticky_obj.get("duration_ms", None)
-            # MSC: Valid values are the integer range 0-3600000 (1 hour).
+            # MSC: Valid values are the integer range 0-MAX_STICKY_DURATION_MS
             if (
                 type(sticky_duration_ms) is int
                 and sticky_duration_ms >= 0
-                and sticky_duration_ms <= 3600000
+                and sticky_duration_ms <= MAX_STICKY_DURATION_MS
             ):
                 # MSC: The start time is min(now, origin_server_ts).
                 # This ensures that malicious origin timestamps cannot specify start times in the future.
-                # Calculate the end time as start_time + min(sticky.duration_ms, 3600000).
+                # Calculate the end time as start_time + min(sticky.duration_ms, MAX_STICKY_DURATION_MS).
                 expires_at = min(ev.origin_server_ts, now_ms) + min(
-                    ev.get_dict()[StickyEvent.FIELD_NAME]["duration_ms"], 3600000
+                    ev.get_dict()[StickyEvent.FIELD_NAME]["duration_ms"],
+                    MAX_STICKY_DURATION_MS,
                 )
                 # filter out already expired sticky events
                 if expires_at > now_ms:
@@ -449,7 +442,7 @@ class StickyEventsWorkerStore(StateGroupWorkerStore, CacheInvalidationWorkerStor
     async def _recheck_soft_failed_events(
         self,
         room_id: str,
-        soft_failed_event_ids: List[str],
+        soft_failed_event_ids: Collection[str],
     ) -> None:
         """
         Recheck authorised but soft-failed events. The provided event IDs must have already passed