try hacking around some more

roomserver/internal/helpers/helpers.go

@@ -67,7 +67,7 @@ func IsServerCurrentlyInRoom(ctx context.Context, db storage.Database, serverNam
 		return db.GetLocalServerInRoom(ctx, info.RoomNID)
 	}
 
-	eventNIDs, err := db.GetMembershipEventNIDsForRoom(ctx, info.RoomNID, true, false)
+	eventNIDs, err := db.GetMembershipEventNIDsForRoom(ctx, info.RoomNID, "", true, false)
 	if err != nil {
 		return false, err
 	}

roomserver/internal/input/input_events.go

@@ -256,7 +256,7 @@ func (r *Inputer) calculateAndSetState(
 		stateAtEvent.Overwrite = true
 		var joinEventNIDs []types.EventNID
 		// Request join memberships only for local users only.
-		if joinEventNIDs, err = r.DB.GetMembershipEventNIDsForRoom(ctx, roomInfo.RoomNID, true, true); err == nil {
+		if joinEventNIDs, err = r.DB.GetMembershipEventNIDsForRoom(ctx, roomInfo.RoomNID, "", true, true); err == nil {
 			// If we have no local users that are joined to the room then any state about
 			// the room that we have is quite possibly out of date. Therefore in that case
 			// we should overwrite it rather than merge it.

roomserver/internal/perform/perform_backfill.go

@@ -537,7 +537,7 @@ func joinEventsFromHistoryVisibility(
 	if err != nil {
 		return nil, err
 	}
-	joinEventNIDs, err := db.GetMembershipEventNIDsForRoom(ctx, info.RoomNID, true, false)
+	joinEventNIDs, err := db.GetMembershipEventNIDsForRoom(ctx, info.RoomNID, "", true, false)
 	if err != nil {
 		return nil, err
 	}

roomserver/internal/query/query.go

@@ -287,7 +287,7 @@ func (r *Queryer) QueryMembershipsForRoom(
 	var stateEntries []types.StateEntry
 	if stillInRoom {
 		var eventNIDs []types.EventNID
-		eventNIDs, err = r.DB.GetMembershipEventNIDsForRoom(ctx, info.RoomNID, request.JoinedOnly, false)
+		eventNIDs, err = r.DB.GetMembershipEventNIDsForRoom(ctx, info.RoomNID, "", request.JoinedOnly, false)
 		if err != nil {
 			return err
 		}

roomserver/storage/shared/storage.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"sort"
+	"strconv"
 
 	"github.com/matrix-org/dendrite/internal/caching"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
@@ -359,7 +360,38 @@ func (d *Database) GetMembershipEventNIDsForRoom(
 	}
 
 	if len(requestAt) > 0 {
-		panic("implement me")
+		var eventNIDs []types.EventNID
+		var eventNIDsAt []types.EventNID
+		var err error
+		var depth int
+
+		depth, err = strconv.Atoi(string(requestAt[1]))
+		if err != nil {
+			return nil, err
+		}
+		fmt.Printf("XXXXXX  %d  XXXXXX", depth)
+
+		eventNIDs, err = d.MembershipTable.SelectMembershipsFromRoom(ctx, roomNID, localOnly)
+		if err != nil {
+			return nil, err
+		}
+
+		var eventNIDString []string
+		for _, nid := range eventNIDs {
+			eventNIDString = append(eventNIDString, fmt.Sprint(nid))
+		}
+		events, err := d.EventsFromIDs(ctx, eventNIDString)
+		if err != nil {
+			return nil, err
+		}
+		for _, ev := range events {
+			fmt.Println(ev)
+			if ev.Depth() <= int64(depth) {
+				eventNIDsAt = append(eventNIDsAt, ev.EventNID)
+			}
+		}
+
+		return eventNIDsAt, nil
 	}
 
 	return d.MembershipTable.SelectMembershipsFromRoom(ctx, roomNID, localOnly)

roomserver/storage/tables/interface.go

@@ -128,7 +128,6 @@ type Membership interface {
 	SelectMembershipForUpdate(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID) (MembershipState, error)
 	SelectMembershipFromRoomAndTarget(ctx context.Context, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID) (types.EventNID, MembershipState, bool, error)
 	SelectMembershipsFromRoom(ctx context.Context, roomNID types.RoomNID, localOnly bool) (eventNIDs []types.EventNID, err error)
-	SelectMembershipsFromRoomPaginated(ctx context.Context, roomNID types.RoomNID, localOnly bool) (eventNIDs []types.EventNID, err error)
 	SelectMembershipsFromRoomAndMembership(ctx context.Context, roomNID types.RoomNID, membership MembershipState, localOnly bool) (eventNIDs []types.EventNID, err error)
 	UpdateMembership(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID, senderUserNID types.EventStateKeyNID, membership MembershipState, eventNID types.EventNID, forgotten bool) error
 	SelectRoomsWithMembership(ctx context.Context, userID types.EventStateKeyNID, membershipState MembershipState) ([]types.RoomNID, error)