Remove support for mixed multi-upstream LIST

Multi-upstream connections can still send LIST commands with a
network suffix.

downstream.go

@@ -1837,48 +1837,34 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 	case "LIST":
 		// TODO: support ELIST when supported by all upstreams
 
-		pl := pendingLIST{
+		network := dc.network
-			downstreamID:    dc.id,
+		if network == nil && len(msg.Params) > 0 {
-			pendingCommands: make(map[int64]*irc.Message),
+			var err error
-		}
+			network, msg.Params[0], err = dc.unmarshalEntityNetwork(msg.Params[0])
-		var upstream *upstreamConn
-		var upstreamChannels map[int64][]string
-		if len(msg.Params) > 0 {
-			uc, upstreamMask, err := dc.unmarshalEntity(msg.Params[0])
-			if err == nil && upstreamMask == "*" { // LIST */network: send LIST only to one network
-				upstream = uc
-			} else {
-				upstreamChannels = make(map[int64][]string)
-				channels := strings.Split(msg.Params[0], ",")
-				for _, channel := range channels {
-					uc, upstreamChannel, err := dc.unmarshalEntity(channel)
 			if err != nil {
 				return err
 			}
-					upstreamChannels[uc.network.ID] = append(upstreamChannels[uc.network.ID], upstreamChannel)
-				}
 		}
+		if network == nil {
+			dc.SendMessage(&irc.Message{
+				Prefix:  dc.srv.prefix(),
+				Command: irc.RPL_LISTEND,
+				Params:  []string{dc.nick, "LIST without a network suffix is not supported in multi-upstream mode"},
+			})
+			return nil
 		}
 
-		dc.user.pendingLISTs = append(dc.user.pendingLISTs, pl)
+		uc := network.conn
-		dc.forEachUpstream(func(uc *upstreamConn) {
+		if uc == nil {
-			if upstream != nil && upstream != uc {
+			dc.SendMessage(&irc.Message{
-				return
+				Prefix:  dc.srv.prefix(),
-			}
+				Command: irc.RPL_LISTEND,
-			var params []string
+				Params:  []string{dc.nick, "Disconnected from upstream server"},
-			if upstreamChannels != nil {
-				if channels, ok := upstreamChannels[uc.network.ID]; ok {
-					params = []string{strings.Join(channels, ",")}
-				} else {
-					return
-				}
-			}
-			pl.pendingCommands[uc.network.ID] = &irc.Message{
-				Command: "LIST",
-				Params:  params,
-			}
-			uc.trySendLIST(dc.id)
 			})
+			return nil
+		}
+
+		uc.enqueueLIST(dc, msg)
 	case "NAMES":
 		if len(msg.Params) == 0 {
 			dc.SendMessage(&irc.Message{

upstream.go

@@ -72,6 +72,11 @@ func (uc *upstreamChannel) updateAutoDetach(dur time.Duration) {
 	})
 }
 
+type pendingUpstreamCommand struct {
+	downstreamID uint64
+	cmd          *irc.Message
+}
+
 type upstreamConn struct {
 	conn
 
@@ -104,8 +109,10 @@ type upstreamConn struct {
 
 	casemapIsSet bool
 
-	// set of LIST commands in progress, per downstream
+	// Queue of LIST commands in progress. The first entry has been sent to the
-	pendingLISTDownstreamSet map[uint64]struct{}
+	// server and is awaiting reply. The following entries have not been sent
+	// yet.
+	pendingLIST []pendingUpstreamCommand
 
 	gotMotd bool
 }
@@ -201,7 +208,6 @@ func connectToUpstream(network *network) (*upstreamConn, error) {
 		availableChannelModes: stdChannelModes,
 		availableMemberships:  stdMemberships,
 		isupport:              make(map[string]*string),
-		pendingLISTDownstreamSet: make(map[uint64]struct{}),
 	}
 	return uc, nil
 }
@@ -235,28 +241,9 @@ func (uc *upstreamConn) isOurNick(nick string) bool {
 	return uc.nickCM == uc.network.casemap(nick)
 }
 
-func (uc *upstreamConn) getPendingLIST() *pendingLIST {
+func (uc *upstreamConn) endPendingLISTs() {
-	for _, pl := range uc.user.pendingLISTs {
+	for _, pendingCmd := range uc.pendingLIST {
-		if _, ok := pl.pendingCommands[uc.network.ID]; !ok {
+		uc.forEachDownstreamByID(pendingCmd.downstreamID, func(dc *downstreamConn) {
-			continue
-		}
-		return &pl
-	}
-	return nil
-}
-
-func (uc *upstreamConn) endPendingLISTs(all bool) (found bool) {
-	found = false
-	for i := 0; i < len(uc.user.pendingLISTs); i++ {
-		pl := uc.user.pendingLISTs[i]
-		if _, ok := pl.pendingCommands[uc.network.ID]; !ok {
-			continue
-		}
-		delete(pl.pendingCommands, uc.network.ID)
-		if len(pl.pendingCommands) == 0 {
-			uc.user.pendingLISTs = append(uc.user.pendingLISTs[:i], uc.user.pendingLISTs[i+1:]...)
-			i--
-			uc.forEachDownstreamByID(pl.downstreamID, func(dc *downstreamConn) {
 			dc.SendMessage(&irc.Message{
 				Prefix:  dc.srv.prefix(),
 				Command: irc.RPL_LISTEND,
@@ -264,46 +251,55 @@ func (uc *upstreamConn) endPendingLISTs(all bool) (found bool) {
 			})
 		})
 	}
-		found = true
+	uc.pendingLIST = nil
-		if !all {
-			delete(uc.pendingLISTDownstreamSet, pl.downstreamID)
-			uc.user.forEachUpstream(func(uc *upstreamConn) {
-				uc.trySendLIST(pl.downstreamID)
-			})
-			return
-		}
-	}
-	return
 }
 
-func (uc *upstreamConn) trySendLIST(downstreamID uint64) {
+func (uc *upstreamConn) sendNextPendingLIST() {
-	if _, ok := uc.pendingLISTDownstreamSet[downstreamID]; ok {
+	if len(uc.pendingLIST) == 0 {
-		// a LIST command is already pending
-		// we will try again when that command is completed
 		return
 	}
+	uc.SendMessage(uc.pendingLIST[0].cmd)
+}
 
-	for _, pl := range uc.user.pendingLISTs {
+func (uc *upstreamConn) enqueueLIST(dc *downstreamConn, cmd *irc.Message) {
-		if pl.downstreamID != downstreamID {
+	uc.pendingLIST = append(uc.pendingLIST, pendingUpstreamCommand{
-			continue
+		downstreamID: dc.id,
-		}
+		cmd:          cmd,
-		// this is the first pending LIST command list of the downstream
+	})
-		listCommand, ok := pl.pendingCommands[uc.network.ID]
-		if !ok {
-			// there is no command for this upstream in these LIST commands
-			// do not send anything
-			continue
-		}
-		// there is a command for this upstream in these LIST commands
-		// send it now
 
-		uc.SendMessageLabeled(downstreamID, listCommand)
+	if len(uc.pendingLIST) == 1 {
-
+		uc.sendNextPendingLIST()
-		uc.pendingLISTDownstreamSet[downstreamID] = struct{}{}
-		return
 	}
 }
 
+func (uc *upstreamConn) currentPendingLIST() (*downstreamConn, *irc.Message) {
+	if len(uc.pendingLIST) == 0 {
+		return nil, nil
+	}
+
+	pendingCmd := uc.pendingLIST[0]
+	for _, dc := range uc.user.downstreamConns {
+		if dc.id == pendingCmd.downstreamID {
+			return dc, pendingCmd.cmd
+		}
+	}
+
+	return nil, pendingCmd.cmd
+}
+
+func (uc *upstreamConn) dequeueLIST() (*downstreamConn, *irc.Message) {
+	dc, cmd := uc.currentPendingLIST()
+
+	if len(uc.pendingLIST) > 0 {
+		copy(uc.pendingLIST, uc.pendingLIST[1:])
+		uc.pendingLIST = uc.pendingLIST[:len(uc.pendingLIST)-1]
+	}
+
+	uc.sendNextPendingLIST()
+
+	return dc, cmd
+}
+
 func (uc *upstreamConn) parseMembershipPrefix(s string) (ms *memberships, nick string) {
 	memberships := make(memberships, 0, 4)
 	i := 0
@@ -1099,23 +1095,31 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return err
 		}
 
-		pl := uc.getPendingLIST()
+		dc, cmd := uc.currentPendingLIST()
-		if pl == nil {
+		if cmd == nil {
 			return fmt.Errorf("unexpected RPL_LIST: no matching pending LIST")
+		} else if dc == nil {
+			return nil
 		}
 
-		uc.forEachDownstreamByID(pl.downstreamID, func(dc *downstreamConn) {
 		dc.SendMessage(&irc.Message{
 			Prefix:  dc.srv.prefix(),
 			Command: irc.RPL_LIST,
 			Params:  []string{dc.nick, dc.marshalEntity(uc.network, channel), clients, topic},
 		})
-		})
 	case irc.RPL_LISTEND:
-		ok := uc.endPendingLISTs(false)
+		dc, cmd := uc.dequeueLIST()
-		if !ok {
+		if cmd == nil {
 			return fmt.Errorf("unexpected RPL_LISTEND: no matching pending LIST")
+		} else if dc == nil {
+			return nil
 		}
+
+		dc.SendMessage(&irc.Message{
+			Prefix:  dc.srv.prefix(),
+			Command: irc.RPL_LISTEND,
+			Params:  []string{dc.nick, "End of /LIST"},
+		})
 	case irc.RPL_NAMREPLY:
 		var name, statusStr, members string
 		if err := parseMessageParams(msg, nil, &statusStr, &name, &members); err != nil {
@@ -1433,10 +1437,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		}
 
 		if command == "LIST" {
-			ok := uc.endPendingLISTs(false)
+			uc.endPendingLISTs()
-			if !ok {
-				return fmt.Errorf("unexpected response for LIST: %q: no matching pending LIST", msg.Command)
-			}
 		}
 
 		uc.forEachDownstreamByID(downstreamID, func(dc *downstreamConn) {

user.go

@@ -405,15 +405,6 @@ type user struct {
 	networks        []*network
 	downstreamConns []*downstreamConn
 	msgStore        messageStore
-
-	// LIST commands in progress
-	pendingLISTs []pendingLIST
-}
-
-type pendingLIST struct {
-	downstreamID uint64
-	// list of per-upstream LIST commands not yet sent or completed
-	pendingCommands map[int64]*irc.Message
 }
 
 func newUser(srv *Server, record *User) *user {
@@ -690,7 +681,7 @@ func (u *user) run() {
 func (u *user) handleUpstreamDisconnected(uc *upstreamConn) {
 	uc.network.conn = nil
 
-	uc.endPendingLISTs(true)
+	uc.endPendingLISTs()
 
 	for _, entry := range uc.channels.innerMap {
 		uch := entry.value.(*upstreamChannel)