Delete irrelevant membership states

roomserver/internal/input/input_membership.go

@@ -99,6 +99,16 @@ func (r *Inputer) updateMembership(
 		}
 	}
 
+	var targetLocal bool
+	if add != nil {
+		targetLocal = r.isLocalTarget(add)
+	}
+
+	mu, err := updater.MembershipUpdater(targetUserNID, targetLocal)
+	if err != nil {
+		return nil, err
+	}
+
 	// In an ideal world, we shouldn't ever have "add" be nil and "remove" be
 	// set, as this implies that we're deleting a state event without replacing
 	// it (a thing that ordinarily shouldn't happen in Matrix). However, state
@@ -108,17 +118,10 @@ func (r *Inputer) updateMembership(
 	// after a state reset, often thinking that the user was still joined to
 	// the room even though the room state said otherwise, and this would prevent
 	// the user from being able to attempt to rejoin the room without modifying
-	// the database. So instead what we'll do is we'll just update the membership
-	// table to say that the user is "leave" and we'll use the old event to
-	// avoid nil pointer exceptions on the code path that follows.
-	if add == nil {
-		add = remove
-		newMembership = gomatrixserverlib.Leave
-	}
-
-	mu, err := updater.MembershipUpdater(targetUserNID, r.isLocalTarget(add))
-	if err != nil {
-		return nil, err
+	// the database. So instead we're going to remove the membership from the
+	// database altogether, so that it doesn't create future problems.
+	if add == nil && remove != nil {
+		return nil, mu.Delete()
 	}
 
 	switch newMembership {

roomserver/internal/perform/perform_leave.go

@@ -30,7 +30,6 @@ import (
 	"github.com/matrix-org/dendrite/roomserver/internal/helpers"
 	"github.com/matrix-org/dendrite/roomserver/internal/input"
 	"github.com/matrix-org/dendrite/roomserver/storage"
-	"github.com/matrix-org/dendrite/roomserver/storage/tables"
 	"github.com/matrix-org/dendrite/setup/config"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
 )
@@ -229,14 +228,14 @@ func (r *Leaver) performFederatedRejectInvite(
 		util.GetLogger(ctx).WithError(err).Errorf("failed to get MembershipUpdater, still retiring invite event")
 	}
 	if updater != nil {
-		if _, _, err = updater.Update(tables.MembershipStateLeaveOrBan, leaveRes.Event.Unwrap()); err != nil {
-			util.GetLogger(ctx).WithError(err).Errorf("failed to set membership to leave, still retiring invite event")
+		if err = updater.Delete(); err != nil {
+			util.GetLogger(ctx).WithError(err).Errorf("failed to delete membership, still retiring invite event")
 			if err = updater.Rollback(); err != nil {
-				util.GetLogger(ctx).WithError(err).Errorf("failed to rollback membership leave, still retiring invite event")
+				util.GetLogger(ctx).WithError(err).Errorf("failed to rollback deleting membership, still retiring invite event")
 			}
 		} else {
 			if err = updater.Commit(); err != nil {
-				util.GetLogger(ctx).WithError(err).Errorf("failed to commit membership update, still retiring invite event")
+				util.GetLogger(ctx).WithError(err).Errorf("failed to commit deleting membership, still retiring invite event")
 			}
 		}
 	}

roomserver/storage/postgres/membership_table.go

@@ -112,6 +112,9 @@ const updateMembershipForgetRoom = "" +
 	"UPDATE roomserver_membership SET forgotten = $3" +
 	" WHERE room_nid = $1 AND target_nid = $2"
 
+const deleteMembershipSQL = "" +
+	"DELETE FROM roomserver_membership WHERE room_nid = $1 AND target_nid = $2"
+
 const selectRoomsWithMembershipSQL = "" +
 	"SELECT room_nid FROM roomserver_membership WHERE membership_nid = $1 AND target_nid = $2 and forgotten = false"
 
@@ -158,6 +161,7 @@ type membershipStatements struct {
 	updateMembershipForgetRoomStmt                  *sql.Stmt
 	selectLocalServerInRoomStmt                     *sql.Stmt
 	selectServerInRoomStmt                          *sql.Stmt
+	deleteMembershipStmt                            *sql.Stmt
 }
 
 func CreateMembershipTable(db *sql.DB) error {
@@ -183,6 +187,7 @@ func PrepareMembershipTable(db *sql.DB) (tables.Membership, error) {
 		{&s.updateMembershipForgetRoomStmt, updateMembershipForgetRoom},
 		{&s.selectLocalServerInRoomStmt, selectLocalServerInRoomSQL},
 		{&s.selectServerInRoomStmt, selectServerInRoomSQL},
+		{&s.deleteMembershipStmt, deleteMembershipSQL},
 	}.Prepare(db)
 }
 
@@ -394,3 +399,13 @@ func (s *membershipStatements) SelectServerInRoom(
 	}
 	return roomNID == nid, nil
 }
+
+func (s *membershipStatements) DeleteMembership(
+	ctx context.Context, txn *sql.Tx,
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.deleteMembershipStmt).ExecContext(
+		ctx, roomNID, targetUserNID,
+	)
+	return err
+}

roomserver/storage/shared/membership_updater.go

@@ -90,6 +90,10 @@ func (u *MembershipUpdater) IsKnock() bool {
 	return u.oldMembership == tables.MembershipStateKnock
 }
 
+func (u *MembershipUpdater) Delete() error {
+	return u.d.MembershipTable.DeleteMembership(u.ctx, u.txn, u.roomNID, u.targetUserNID)
+}
+
 func (u *MembershipUpdater) Update(newMembership tables.MembershipState, event *gomatrixserverlib.Event) (bool, []string, error) {
 	var inserted bool
 	var retired []string

roomserver/storage/sqlite3/membership_table.go

@@ -119,6 +119,9 @@ const selectServerInRoomSQL = "" +
 	" JOIN roomserver_event_state_keys ON roomserver_membership.target_nid = roomserver_event_state_keys.event_state_key_nid" +
 	" WHERE membership_nid = $1 AND room_nid = $2 AND event_state_key LIKE '%:' || $3 LIMIT 1"
 
+const deleteMembershipSQL = "" +
+	"DELETE FROM roomserver_membership WHERE room_nid = $1 AND target_nid = $2"
+
 type membershipStatements struct {
 	db                                              *sql.DB
 	insertMembershipStmt                            *sql.Stmt
@@ -134,6 +137,7 @@ type membershipStatements struct {
 	updateMembershipForgetRoomStmt                  *sql.Stmt
 	selectLocalServerInRoomStmt                     *sql.Stmt
 	selectServerInRoomStmt                          *sql.Stmt
+	deleteMembershipStmt                            *sql.Stmt
 }
 
 func CreateMembershipTable(db *sql.DB) error {
@@ -160,6 +164,7 @@ func PrepareMembershipTable(db *sql.DB) (tables.Membership, error) {
 		{&s.updateMembershipForgetRoomStmt, updateMembershipForgetRoom},
 		{&s.selectLocalServerInRoomStmt, selectLocalServerInRoomSQL},
 		{&s.selectServerInRoomStmt, selectServerInRoomSQL},
+		{&s.deleteMembershipStmt, deleteMembershipSQL},
 	}.Prepare(db)
 }
 
@@ -373,3 +378,13 @@ func (s *membershipStatements) SelectServerInRoom(ctx context.Context, txn *sql.
 	}
 	return roomNID == nid, nil
 }
+
+func (s *membershipStatements) DeleteMembership(
+	ctx context.Context, txn *sql.Tx,
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.deleteMembershipStmt).ExecContext(
+		ctx, roomNID, targetUserNID,
+	)
+	return err
+}

roomserver/storage/tables/interface.go

@@ -133,6 +133,7 @@ type Membership interface {
 	UpdateForgetMembership(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID, forget bool) error
 	SelectLocalServerInRoom(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID) (bool, error)
 	SelectServerInRoom(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, serverName gomatrixserverlib.ServerName) (bool, error)
+	DeleteMembership(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID) error
 }
 
 type Published interface {