More invite support (#979)

* Update gomatixserverlib

* Try to build invite stripped state if not given to us

* SendInvite improvements

* Transpose invite_room_state into invite_state.events for sync API

* Remove syncapi debugging output

* Use RespInviteV2

* Update gomatrixserverlib

* Send the invite event as a normal roomserver event too, for incorporating into room (should this be done by the roomserver automatically for invite inputs?)

* Federation sender use invite_room_state, room server try to insert membership state

* Check supported room versions on the invite endpoint

* Prevent roomserver query API from trying to handle requests for stub rooms

* Adding a nolint

* Replace IsRoomStub with RoomNIDExcludingStubs, fix query API to use that instead

* Review comments

1 files changed, 30 insertions, 12 deletions

diff --git a/clientapi/routing/membership.go b/clientapi/routing/membership.go
index 9f386b71..c597dd27 100644
--- a/clientapi/routing/membership.go
+++ b/clientapi/routing/membership.go
@@ -40,6 +40,8 @@ var errMissingUserID = errors.New("'user_id' must be supplied")
 
 // SendMembership implements PUT /rooms/{roomID}/(join|kick|ban|unban|leave|invite)
 // by building a m.room.member event then sending it to the room server
+// TODO: Can we improve the cyclo count here? Separate code paths for invites?
+// nolint:gocyclo
 func SendMembership(
 	req *http.Request, accountDB accounts.Database, device *authtypes.Device,
 	roomID string, membership string, cfg *config.Dendrite,
@@ -104,23 +106,39 @@ func SendMembership(
 		return jsonerror.InternalServerError()
 	}
 
-	if _, err := producer.SendEvents(
-		req.Context(),
-		[]gomatrixserverlib.HeaderedEvent{(*event).Headered(verRes.RoomVersion)},
-		cfg.Matrix.ServerName,
-		nil,
-	); err != nil {
-		util.GetLogger(req.Context()).WithError(err).Error("producer.SendEvents failed")
-		return jsonerror.InternalServerError()
-	}
-
 	var returnData interface{} = struct{}{}
 
-	// The join membership requires the room id to be sent in the response
-	if membership == gomatrixserverlib.Join {
+	switch membership {
+	case gomatrixserverlib.Invite:
+		// Invites need to be handled specially
+		err = producer.SendInvite(
+			req.Context(),
+			event.Headered(verRes.RoomVersion),
+			nil, // ask the roomserver to draw up invite room state for us
+			cfg.Matrix.ServerName,
+			nil,
+		)
+		if err != nil {
+			util.GetLogger(req.Context()).WithError(err).Error("producer.SendInvite failed")
+			return jsonerror.InternalServerError()
+		}
+	case gomatrixserverlib.Join:
+		// The join membership requires the room id to be sent in the response
 		returnData = struct {
 			RoomID string `json:"room_id"`
 		}{roomID}
+	default:
+	}
+
+	_, err = producer.SendEvents(
+		req.Context(),
+		[]gomatrixserverlib.HeaderedEvent{event.Headered(verRes.RoomVersion)},
+		cfg.Matrix.ServerName,
+		nil,
+	)
+	if err != nil {
+		util.GetLogger(req.Context()).WithError(err).Error("producer.SendEvents failed")
+		return jsonerror.InternalServerError()
 	}
 
 	return util.JSONResponse{