Miscellaneous fixes (#1060)

* Add missing routing for PerformDirectoryLookupRequest

* Tweak output

* Fix some bugs in devices

* Don't default to federated room joins in response to invite

* Update sytest-whitelist

* Update comments

* Return correct room ID from PerformJoin

* Fix appservice and EDU server API setup, update sytest-whitelist

* Update sytest-whitelist

2 files changed, 27 insertions, 10 deletions

diff --git a/roomserver/api/perform.go b/roomserver/api/perform.go
index c98f91fb..f5afd67b 100644
--- a/roomserver/api/perform.go
+++ b/roomserver/api/perform.go
@@ -24,6 +24,7 @@ type PerformJoinRequest struct {
 }
 
 type PerformJoinResponse struct {
+	RoomID string `json:"room_id"`
 }
 
 func (h *httpRoomserverInternalAPI) PerformJoin(
diff --git a/roomserver/internal/perform_join.go b/roomserver/internal/perform_join.go
index dc786b29..75dfdd19 100644
--- a/roomserver/internal/perform_join.go
+++ b/roomserver/internal/perform_join.go
@@ -90,6 +90,12 @@ func (r *RoomserverInternalAPI) performJoinRoomByID(
 	req *api.PerformJoinRequest,
 	res *api.PerformJoinResponse, // nolint:unparam
 ) error {
+	// By this point, if req.RoomIDOrAlias contained an alias, then
+	// it will have been overwritten with a room ID by performJoinRoomByAlias.
+	// We should now include this in the response so that the CS API can
+	// return the right room ID.
+	res.RoomID = req.RoomIDOrAlias
+
 	// Get the domain part of the room ID.
 	_, domain, err := gomatrixserverlib.SplitID('!', req.RoomIDOrAlias)
 	if err != nil {
@@ -121,20 +127,30 @@ func (r *RoomserverInternalAPI) performJoinRoomByID(
 		return fmt.Errorf("eb.SetContent: %w", err)
 	}
 
-	// First work out if this is in response to an existing invite.
-	// If it is then we avoid the situation where we might think we
-	// know about a room in the following section but don't know the
-	// latest state as all of our users have left.
+	// First work out if this is in response to an existing invite
+	// from a federated server. If it is then we avoid the situation
+	// where we might think we know about a room in the following
+	// section but don't know the latest state as all of our users
+	// have left.
 	isInvitePending, inviteSender, err := r.isInvitePending(ctx, req.RoomIDOrAlias, req.UserID)
 	if err == nil && isInvitePending {
-		// Add the server of the person who invited us to the server list,
-		// as they should be a fairly good bet.
-		if _, inviterDomain, ierr := gomatrixserverlib.SplitID('@', inviteSender); ierr == nil {
-			req.ServerNames = append(req.ServerNames, inviterDomain)
+		// Check if there's an invite pending.
+		_, inviterDomain, ierr := gomatrixserverlib.SplitID('@', inviteSender)
+		if ierr != nil {
+			return fmt.Errorf("gomatrixserverlib.SplitID: %w", err)
 		}
 
-		// Perform a federated room join.
-		return r.performFederatedJoinRoomByID(ctx, req, res)
+		// Check that the domain isn't ours. If it's local then we don't
+		// need to do anything as our own copy of the room state will be
+		// up-to-date.
+		if inviterDomain != r.Cfg.Matrix.ServerName {
+			// Add the server of the person who invited us to the server list,
+			// as they should be a fairly good bet.
+			req.ServerNames = append(req.ServerNames, inviterDomain)
+
+			// Perform a federated room join.
+			return r.performFederatedJoinRoomByID(ctx, req, res)
+		}
 	}
 
 	// Try to construct an actual join event from the template.