MSC2836 threading: part 2 (#1596)

* Update GMSL

* Add MSC2836EventRelationships to fedsender

* Call MSC2836EventRelationships in reqCtx

* auth remote servers

* Extract room ID and servers from previous events; refactor a bit

* initial cut of federated threading

* Use the right client/fed struct in the response

* Add QueryAuthChain for use with MSC2836

* Add auth chain to federated response

* Fix pointers

* under CI: more logging and enable mscs, nil fix

* Handle direction: up

* Actually send message events to the roomserver..

* Add children and children_hash to unsigned, with tests

* Add logic for exploring threads and tracking children; missing storage functions

* Implement storage functions for children

* Add fetchUnknownEvent

* Do federated hits for include_children if we have unexplored children

* Use /ev_rel rather than /event as the former includes child metadata

* Remove cross-room threading impl

* Enable MSC2836 in the p2p demo

* Namespace mscs db

* Enable msc2836 for ygg

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

roomserver/api/api.go

@@ -132,6 +132,15 @@ type RoomserverInternalAPI interface {
 		response *QueryStateAndAuthChainResponse,
 	) error
 
+	// QueryAuthChain returns the entire auth chain for the event IDs given.
+	// The response includes the events in the request.
+	// Omits without error for any missing auth events. There will be no duplicates.
+	QueryAuthChain(
+		ctx context.Context,
+		request *QueryAuthChainRequest,
+		response *QueryAuthChainResponse,
+	) error
+
 	// QueryCurrentState retrieves the requested state events. If state events are not found, they will be missing from
 	// the response.
 	QueryCurrentState(ctx context.Context, req *QueryCurrentStateRequest, res *QueryCurrentStateResponse) error

roomserver/api/api_trace.go

@@ -324,6 +324,16 @@ func (t *RoomserverInternalAPITrace) QueryServerBannedFromRoom(ctx context.Conte
 	return err
 }
 
+func (t *RoomserverInternalAPITrace) QueryAuthChain(
+	ctx context.Context,
+	request *QueryAuthChainRequest,
+	response *QueryAuthChainResponse,
+) error {
+	err := t.Impl.QueryAuthChain(ctx, request, response)
+	util.GetLogger(ctx).WithError(err).Infof("QueryAuthChain req=%+v res=%+v", js(request), js(response))
+	return err
+}
+
 func js(thing interface{}) string {
 	b, err := json.Marshal(thing)
 	if err != nil {

roomserver/api/query.go

@@ -275,6 +275,14 @@ type QueryPublishedRoomsResponse struct {
 	RoomIDs []string
 }
 
+type QueryAuthChainRequest struct {
+	EventIDs []string
+}
+
+type QueryAuthChainResponse struct {
+	AuthChain []*gomatrixserverlib.HeaderedEvent
+}
+
 type QuerySharedUsersRequest struct {
 	UserID         string
 	ExcludeRoomIDs []string