Other fixes

roomserver/storage/shared/room_updater.go

@@ -32,12 +32,8 @@ func NewRoomUpdater(ctx context.Context, d *Database, txn *sql.Tx, roomInfo *typ
 	// we will just run with a normal database transaction. It'll either
 	// succeed, processing a create event which creates the room, or it won't.
 	if roomInfo == nil {
-		tx, err := d.DB.Begin()
-		if err != nil {
-			return nil, fmt.Errorf("d.DB.Begin: %w", err)
-		}
 		return &RoomUpdater{
-			transaction{ctx, tx}, d, nil, nil, "", 0,
+			transaction{ctx, txn}, d, nil, nil, "", 0,
 		}, nil
 	}
 

roomserver/storage/shared/storage.go

@@ -588,25 +588,27 @@ func (d *Database) storeEvent(
 	// events updater because it somewhat works as a mutex, ensuring
 	// that there's a row-level lock on the latest room events (well,
 	// on Postgres at least).
-	var roomInfo *types.RoomInfo
 	if prevEvents := event.PrevEvents(); len(prevEvents) > 0 {
-		roomInfo, err = d.RoomInfo(ctx, event.RoomID())
-		if err != nil {
-			return 0, 0, types.StateAtEvent{}, nil, "", fmt.Errorf("d.RoomInfo: %w", err)
-		}
-		if roomInfo == nil && len(prevEvents) > 0 {
-			return 0, 0, types.StateAtEvent{}, nil, "", fmt.Errorf("expected room %q to exist", event.RoomID())
-		}
 		// Create an updater - NB: on sqlite this WILL create a txn as we are directly calling the shared DB form of
 		// GetLatestEventsForUpdate - not via the SQLiteDatabase form which has `nil` txns. This
 		// function only does SELECTs though so the created txn (at this point) is just a read txn like
 		// any other so this is fine. If we ever update GetLatestEventsForUpdate or NewLatestEventsUpdater
 		// to do writes however then this will need to go inside `Writer.Do`.
+		succeeded := false
 		if updater == nil {
+			var roomInfo *types.RoomInfo
+			roomInfo, err = d.RoomInfo(ctx, event.RoomID())
+			if err != nil {
+				return 0, 0, types.StateAtEvent{}, nil, "", fmt.Errorf("d.RoomInfo: %w", err)
+			}
+			if roomInfo == nil && len(prevEvents) > 0 {
+				return 0, 0, types.StateAtEvent{}, nil, "", fmt.Errorf("expected room %q to exist", event.RoomID())
+			}
 			updater, err = d.GetRoomUpdater(ctx, roomInfo)
 			if err != nil {
 				return 0, 0, types.StateAtEvent{}, nil, "", fmt.Errorf("GetRoomUpdater: %w", err)
 			}
+			defer sqlutil.EndTransactionWithCheck(updater.txn, &succeeded, &err)
 		}
 		// Ensure that we atomically store prev events AND commit them. If we don't wrap StorePreviousEvents
 		// and EndTransaction in a writer then it's possible for a new write txn to be made between the two
@@ -618,9 +620,8 @@ func (d *Database) storeEvent(
 			if err = updater.StorePreviousEvents(eventNID, prevEvents); err != nil {
 				return fmt.Errorf("updater.StorePreviousEvents: %w", err)
 			}
-			succeeded := true
-			err = sqlutil.EndTransaction(updater, &succeeded)
-			return err
+			succeeded = true
+			return nil
 		})
 		if err != nil {
 			return 0, 0, types.StateAtEvent{}, nil, "", err