From 35d29724943e123d866c4c49c8a42a18543fa6cb Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 16 Oct 2020 11:31:05 +0100
Subject: [PATCH] Don't run the latest events updater at all for KindOld

---
 roomserver/internal/input/input.go            |  1 +
 roomserver/internal/input/input_events.go     | 23 ++++-----
 .../internal/input/input_latest_events.go     | 49 ++++++++-----------
 3 files changed, 34 insertions(+), 39 deletions(-)

diff --git a/roomserver/internal/input/input.go b/roomserver/internal/input/input.go
index d340ac218..b5d20a05e 100644
--- a/roomserver/internal/input/input.go
+++ b/roomserver/internal/input/input.go
@@ -85,6 +85,7 @@ func (r *Inputer) WriteOutputEvents(roomID string, updates []api.OutputEvent) er
 			logger = logger.WithFields(log.Fields{
 				"event_type":     updates[i].NewRoomEvent.Event.Type(),
 				"event_id":       updates[i].NewRoomEvent.Event.EventID(),
+				"is_fwd_extrem":  updates[i].NewRoomEvent.IsForwardExtremity,
 				"adds_state":     len(updates[i].NewRoomEvent.AddsStateEventIDs),
 				"removes_state":  len(updates[i].NewRoomEvent.RemovesStateEventIDs),
 				"send_as_server": updates[i].NewRoomEvent.SendAsServer,
diff --git a/roomserver/internal/input/input_events.go b/roomserver/internal/input/input_events.go
index 270f243c9..1fcdc0c11 100644
--- a/roomserver/internal/input/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -136,17 +136,18 @@ func (r *Inputer) processRoomEvent(
 		return event.EventID(), rejectionErr
 	}
 
-	if err = r.updateLatestEvents(
-		ctx,                 // context
-		roomInfo,            // room info for the room being updated
-		stateAtEvent,        // state at event (below)
-		input.Kind,          // kind of event
-		event,               // event
-		input.SendAsServer,  // send as server
-		input.TransactionID, // transaction ID
-		input.HasState,      // rewrites state?
-	); err != nil {
-		return "", fmt.Errorf("r.updateLatestEvents: %w", err)
+	if input.Kind == api.KindNew {
+		if err = r.updateLatestEvents(
+			ctx,                 // context
+			roomInfo,            // room info for the room being updated
+			stateAtEvent,        // state at event (below)
+			event,               // event
+			input.SendAsServer,  // send as server
+			input.TransactionID, // transaction ID
+			input.HasState,      // rewrites state?
+		); err != nil {
+			return "", fmt.Errorf("r.updateLatestEvents: %w", err)
+		}
 	}
 
 	// processing this event resulted in an event (which may not be the one we're processing)
diff --git a/roomserver/internal/input/input_latest_events.go b/roomserver/internal/input/input_latest_events.go
index 5ef5b93b2..81e5eb663 100644
--- a/roomserver/internal/input/input_latest_events.go
+++ b/roomserver/internal/input/input_latest_events.go
@@ -52,7 +52,6 @@ func (r *Inputer) updateLatestEvents(
 	ctx context.Context,
 	roomInfo *types.RoomInfo,
 	stateAtEvent types.StateAtEvent,
-	kind api.Kind,
 	event gomatrixserverlib.Event,
 	sendAsServer string,
 	transactionID *api.TransactionID,
@@ -71,7 +70,6 @@ func (r *Inputer) updateLatestEvents(
 		updater:       updater,
 		roomInfo:      roomInfo,
 		stateAtEvent:  stateAtEvent,
-		kind:          kind,
 		event:         event,
 		sendAsServer:  sendAsServer,
 		transactionID: transactionID,
@@ -97,7 +95,6 @@ type latestEventsUpdater struct {
 	roomInfo      *types.RoomInfo
 	stateAtEvent  types.StateAtEvent
 	event         gomatrixserverlib.Event
-	kind          api.Kind
 	transactionID *api.TransactionID
 	rewritesState bool
 	// Which server to send this event as.
@@ -144,33 +141,29 @@ func (u *latestEventsUpdater) doUpdateLatestEvents() error {
 		return nil
 	}
 
-	var updates []api.OutputEvent
-	var err error
-	if u.kind == api.KindNew {
-		// Work out what the latest events are. This will include the new
-		// event if it is not already referenced.
-		if err = u.calculateLatest(
-			oldLatest,
-			types.StateAtEventAndReference{
-				EventReference: u.event.EventReference(),
-				StateAtEvent:   u.stateAtEvent,
-			},
-		); err != nil {
-			return fmt.Errorf("u.calculateLatest: %w", err)
-		}
+	// Work out what the latest events are. This will include the new
+	// event if it is not already referenced.
+	if err := u.calculateLatest(
+		oldLatest,
+		types.StateAtEventAndReference{
+			EventReference: u.event.EventReference(),
+			StateAtEvent:   u.stateAtEvent,
+		},
+	); err != nil {
+		return fmt.Errorf("u.calculateLatest: %w", err)
+	}
 
-		// Now that we know what the latest events are, it's time to get the
-		// latest state.
-		if err = u.latestState(); err != nil {
-			return fmt.Errorf("u.latestState: %w", err)
-		}
+	// Now that we know what the latest events are, it's time to get the
+	// latest state.
+	if err := u.latestState(); err != nil {
+		return fmt.Errorf("u.latestState: %w", err)
+	}
 
-		// If we need to generate any output events then here's where we do it.
-		// TODO: Move this!
-		updates, err = u.api.updateMemberships(u.ctx, u.updater, u.removed, u.added)
-		if err != nil {
-			return fmt.Errorf("u.api.updateMemberships: %w", err)
-		}
+	// If we need to generate any output events then here's where we do it.
+	// TODO: Move this!
+	updates, err := u.api.updateMemberships(u.ctx, u.updater, u.removed, u.added)
+	if err != nil {
+		return fmt.Errorf("u.api.updateMemberships: %w", err)
 	}
 
 	update, err := u.makeOutputNewRoomEvent()