README.md

@@ -268,10 +268,15 @@ rules). Case-sensitive comparison is unambiguous.
 A single user session can have multiple clients (phone, laptop, terminal).
 
 - Each client gets a **separate server-to-client (S2C) message queue**.
-- The server fans out messages and events from other users, and the user's own
+- The server fans out messages and events from other users to every client queue
-  DMs and the channel messages it sends over the HTTP API, to every client queue
+  for that user session.
-  for that user session. Replies to a command (numerics) go only to the client
+- When the user sends a `PRIVMSG`, `NOTICE`, `JOIN`, `PART`, `NICK`, `TOPIC`,
-  that sent it.
+  `MODE` or `KICK` from one of its clients, the resulting event goes to every
+  client queue of the user's own session, as well as to the other users it is
+  meant for. The one exception is an IRC listener connection that sent the
+  command, which gets nothing queued for it: it has already sent its user the
+  echo, or, for `PRIVMSG` and `NOTICE`, IRC sends none.
+- Replies to a command (numerics) go only to the client that sent it.
 - `GET /api/v1/messages` delivers from the calling client's specific queue,
   identified by the auth cookie.
 - Client queues have **independent expiry/pruning** — one client going offline
@@ -744,7 +749,7 @@ Leave a channel.
 {"command": "PART", "to": "#general", "body": ["goodbye"]}
 ```
 
-**S2C (broadcast to the other channel members):**
+**S2C (broadcast to all channel members, including the departing user):**
 
 ```json
 {
@@ -760,9 +765,8 @@ Leave a channel.
 
 **Behavior:**
 
-- The PART event goes to the other channel members, not to the departing user;
+- The PART event goes to every channel member, the departing user's own clients
-  the HTTP response confirms the part. (The IRC listener echoes the PART to its
+  included. (An IRC listener connection that sends a PART echoes it itself.)
-  own connection.)
 - If the channel is empty after the user leaves, the channel is **deleted**
   (ephemeral channels).
 - If the user is not in the channel, the server returns an error.

internal/cli/app.go

@@ -757,7 +757,7 @@ func (a *App) handleServerMessage(msg *api.Message) {
 	case irc.CmdJoin:
 		a.handleJoinEvent(msg, timestamp)
 	case irc.CmdPart:
-		a.handlePartEvent(msg, timestamp)
+		a.handlePartEvent(msg, timestamp, myNick)
 	case irc.CmdQuit:
 		a.handleQuitEvent(msg, timestamp)
 	case irc.CmdNick:
@@ -813,10 +813,14 @@ func (a *App) handleJoinEvent(
 	))
 }
 
+// handlePartEvent shows another user's part. The server
+// also sends the user's own part back to it, which cmdPart
+// has already shown; showing it again would add a second
+// line and mark the channel just left as unread.
 func (a *App) handlePartEvent(
-	msg *api.Message, timestamp string,
+	msg *api.Message, timestamp, myNick string,
 ) {
-	if msg.To == "" {
+	if msg.To == "" || msg.From == myNick {
 		return
 	}
 

internal/cli/app_internal_test.go

@@ -3,7 +3,9 @@ package cli
 import (
 	"testing"
 
+	"github.com/gdamore/tcell/v2"
 	api "sneak.berlin/go/neoirc/internal/cli/api"
+	"sneak.berlin/go/neoirc/pkg/irc"
 )
 
 func TestMemberPrefix(t *testing.T) {
@@ -49,3 +51,66 @@ func TestMemberPrefix(t *testing.T) {
 		})
 	}
 }
+
+// TestPartEvent checks that a PART event adds a line to the
+// channel's buffer and marks it unread, except for the
+// user's own part, which cmdPart has already shown.
+func TestPartEvent(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		from       string
+		wantLines  int
+		wantUnread int
+	}{
+		{name: "own part", from: "erin", wantLines: 0, wantUnread: 0},
+		{name: "other member", from: "bob", wantLines: 1, wantUnread: 1},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			app := &App{ui: NewUI(), nick: "erin"}
+			runUI(t, app.ui)
+
+			app.handleServerMessage(&api.Message{
+				Command: irc.CmdPart, From: test.from, To: "#chan",
+			})
+
+			var lines, unread int
+
+			app.ui.app.QueueUpdate(func() {
+				buf := app.ui.getOrCreateBuffer("#chan")
+				lines = len(buf.Lines)
+				unread = buf.Unread
+			})
+
+			if lines != test.wantLines || unread != test.wantUnread {
+				t.Fatalf("got %d lines and %d unread, want %d and %d",
+					lines, unread, test.wantLines, test.wantUnread)
+			}
+		})
+	}
+}
+
+// runUI runs ui on a simulated screen until the test ends.
+func runUI(t *testing.T, ui *UI) {
+	t.Helper()
+
+	ui.app.SetScreen(tcell.NewSimulationScreen(""))
+
+	done := make(chan error)
+
+	go func() { done <- ui.Run() }()
+
+	t.Cleanup(func() {
+		ui.Stop()
+
+		err := <-done
+		if err != nil {
+			t.Errorf("run ui: %v", err)
+		}
+	})
+}

internal/db/queries.go

@@ -1208,11 +1208,12 @@ func insertMessageInTx(
 	return dbID, msgUUID, nil
 }
 
-// EnqueueToSession adds a message to all clients of a
+// EnqueueToSession adds a message to the queues of all
-// session's queues.
+// clients of a session except client skipClientID, or of all
+// of them when skipClientID is 0.
 func (database *Database) EnqueueToSession(
 	ctx context.Context,
-	sessionID, messageID int64,
+	sessionID, messageID, skipClientID int64,
 ) error {
 	transaction, err := database.conn.BeginTx(ctx, nil)
 	if err != nil {
@@ -1221,7 +1222,9 @@ func (database *Database) EnqueueToSession(
 
 	defer func() { _ = transaction.Rollback() }()
 
-	err = enqueueToSessionInTx(ctx, transaction, sessionID, messageID)
+	err = enqueueToSessionInTx(
+		ctx, transaction, sessionID, messageID, skipClientID,
+	)
 	if err != nil {
 		return err
 	}
@@ -1239,15 +1242,15 @@ func (database *Database) EnqueueToSession(
 func enqueueToSessionInTx(
 	ctx context.Context,
 	transaction *sql.Tx,
-	sessionID, messageID int64,
+	sessionID, messageID, skipClientID int64,
 ) error {
 	_, err := transaction.ExecContext(ctx,
 		`INSERT OR IGNORE INTO client_queues
 		 (client_id, message_id, created_at)
 		 SELECT c.id, ?, ?
 		 FROM clients c
-		 WHERE c.session_id = ?`,
+		 WHERE c.session_id = ? AND c.id != ?`,
-		messageID, time.Now(), sessionID)
+		messageID, time.Now(), sessionID, skipClientID)
 	if err != nil {
 		return fmt.Errorf(
 			"enqueue to session: %w", err,
@@ -1673,7 +1676,7 @@ func quitSessionInTx(
 
 	for _, peerID := range peerIDs {
 		err = enqueueToSessionInTx(
-			ctx, transaction, peerID, messageID,
+			ctx, transaction, peerID, messageID, 0,
 		)
 		if err != nil {
 			return nil, err

internal/db/queries_test.go

@@ -675,7 +675,7 @@ func TestPollMessages(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = database.EnqueueToSession(ctx, sid, dbID)
+	err = database.EnqueueToSession(ctx, sid, dbID, 0)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/handlers/api.go

@@ -1257,9 +1257,11 @@ func (hdlr *Handlers) handleChannelMsg(
 ) {
 	ctx := request.Context()
 
-	// Delegate validation + fan-out to service layer.
+	// Delegate validation + fan-out to service layer. The
-	dbID, uuid, err := hdlr.svc.SendChannelMessage(
+	// fan-out includes the sender's own session, so all
-		ctx, sessionID, nick,
+	// their clients see the message in long-poll responses.
+	uuid, err := hdlr.svc.SendChannelMessage(
+		ctx, sessionID, 0, nick,
 		command, target, body, meta,
 	)
 	if hdlr.handleServiceError(
@@ -1269,13 +1271,6 @@ func (hdlr *Handlers) handleChannelMsg(
 		return
 	}
 
-	// HTTP echo: enqueue to sender so all their clients
-	// see the message in long-poll responses.
-	_ = hdlr.params.Database.EnqueueToSession(
-		ctx, sessionID, dbID,
-	)
-	hdlr.broker.Notify(sessionID)
-
 	hdlr.respondJSON(writer, request,
 		map[string]string{"id": uuid, statusKey: "sent"},
 		http.StatusOK)
@@ -1290,7 +1285,7 @@ func (hdlr *Handlers) handleDirectMsg(
 	meta json.RawMessage,
 ) {
 	result, err := hdlr.svc.SendDirectMessage(
-		request.Context(), sessionID, nick,
+		request.Context(), sessionID, 0, nick,
 		command, target, body, meta,
 	)
 	if hdlr.handleServiceError(
@@ -1361,7 +1356,7 @@ func (hdlr *Handlers) executeJoin(
 	nick, channel, suppliedKey string,
 ) {
 	result, err := hdlr.svc.JoinChannel(
-		request.Context(), sessionID, nick,
+		request.Context(), sessionID, 0, nick,
 		channel, suppliedKey,
 	)
 	if hdlr.handleServiceError(
@@ -1545,7 +1540,7 @@ func (hdlr *Handlers) handlePart(
 	}
 
 	err := hdlr.svc.PartChannel(
-		request.Context(), sessionID,
+		request.Context(), sessionID, 0,
 		nick, channel, reason,
 	)
 	if hdlr.handleServiceError(
@@ -1616,7 +1611,7 @@ func (hdlr *Handlers) executeNickChange(
 	nick, newNick string,
 ) {
 	err := hdlr.svc.ChangeNick(
-		request.Context(), sessionID, nick, newNick,
+		request.Context(), sessionID, 0, nick, newNick,
 	)
 	if hdlr.handleServiceError(
 		writer, request,
@@ -1671,7 +1666,7 @@ func (hdlr *Handlers) handleTopic(
 	topic := strings.Join(lines, " ")
 
 	err := hdlr.svc.SetTopic(
-		request.Context(), sessionID,
+		request.Context(), sessionID, 0,
 		nick, channel, topic,
 	)
 	if hdlr.handleServiceError(
@@ -2157,7 +2152,7 @@ func (hdlr *Handlers) applyUserMode(
 
 	modeText := modeArgs[0] + " " + targetNick
 	hdlr.svc.BroadcastMode(
-		request.Context(), nick, channel, chID,
+		request.Context(), 0, nick, channel, chID,
 		modeText,
 	)
 
@@ -2203,7 +2198,7 @@ func (hdlr *Handlers) setChannelFlag(
 	}
 
 	hdlr.svc.BroadcastMode(
-		request.Context(), nick, channel, chID,
+		request.Context(), 0, nick, channel, chID,
 		modeStr,
 	)
 
@@ -3650,7 +3645,7 @@ func (hdlr *Handlers) handleKick(
 	}
 
 	err := hdlr.svc.KickUser(
-		request.Context(), sessionID, nick,
+		request.Context(), sessionID, 0, nick,
 		channel, targetNick, reason,
 	)
 	if hdlr.handleServiceError(
@@ -3723,7 +3718,7 @@ func (hdlr *Handlers) fanOut(
 
 	for _, sid := range sessionIDs {
 		enqErr := hdlr.params.Database.EnqueueToSession(
-			request.Context(), sid, dbID,
+			request.Context(), sid, dbID, 0,
 		)
 		if enqErr != nil {
 			hdlr.log.Error("enqueue failed",

internal/handlers/api_test.go

@@ -2905,7 +2905,7 @@ func (tserver *testServer) queueMessage(
 		return fmt.Errorf("insert message: %w", err)
 	}
 
-	err = tserver.database.EnqueueToSession(ctx, sessionID, msgID)
+	err = tserver.database.EnqueueToSession(ctx, sessionID, msgID, 0)
 	if err != nil {
 		return fmt.Errorf("enqueue: %w", err)
 	}

internal/ircserver/commands.go

@@ -84,7 +84,7 @@ func (c *Conn) handleNick(
 	oldNick := c.nick
 
 	err := c.svc.ChangeNick(
-		ctx, c.sessionID, oldNick, newNick,
+		ctx, c.sessionID, c.clientID, oldNick, newNick,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -128,8 +128,8 @@ func (c *Conn) handlePrivmsg(
 	body, _ := json.Marshal([]string{text}) //nolint:errchkjson
 
 	if strings.HasPrefix(target, "#") {
-		_, _, err := c.svc.SendChannelMessage(
+		_, err := c.svc.SendChannelMessage(
-			ctx, c.sessionID, c.nick,
+			ctx, c.sessionID, c.clientID, c.nick,
 			msg.Command, target, body, nil,
 		)
 		if err != nil {
@@ -137,7 +137,7 @@ func (c *Conn) handlePrivmsg(
 		}
 	} else {
 		result, err := c.svc.SendDirectMessage(
-			ctx, c.sessionID, c.nick,
+			ctx, c.sessionID, c.clientID, c.nick,
 			msg.Command, target, body, nil,
 		)
 		if err != nil {
@@ -199,7 +199,7 @@ func (c *Conn) joinChannel(
 	channel, key string,
 ) {
 	result, err := c.svc.JoinChannel(
-		ctx, c.sessionID, c.nick, channel, key,
+		ctx, c.sessionID, c.clientID, c.nick, channel, key,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -337,7 +337,7 @@ func (c *Conn) partChannel(
 	channel, reason string,
 ) {
 	err := c.svc.PartChannel(
-		ctx, c.sessionID, c.nick, channel, reason,
+		ctx, c.sessionID, c.clientID, c.nick, channel, reason,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -401,7 +401,7 @@ func (c *Conn) handleTopic(
 	newTopic := msg.Params[1]
 
 	err := c.svc.SetTopic(
-		ctx, c.sessionID, c.nick, channel, newTopic,
+		ctx, c.sessionID, c.clientID, c.nick, channel, newTopic,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -708,7 +708,7 @@ func (c *Conn) applyChannelModes(
 		c.send(FormatMessage(c.hostmask(), "MODE", params...))
 
 		c.svc.BroadcastMode(
-			ctx, c.nick, channel, chID, modeReply,
+			ctx, c.clientID, c.nick, channel, chID, modeReply,
 		)
 	}
 }
@@ -1185,7 +1185,7 @@ func (c *Conn) handleKick(
 	}
 
 	err := c.svc.KickUser(
-		ctx, c.sessionID, c.nick,
+		ctx, c.sessionID, c.clientID, c.nick,
 		channel, targetNick, reason,
 	)
 	if err != nil {
@@ -1267,7 +1267,7 @@ func (c *Conn) handleInvite(
 
 	_, _, _ = c.svc.FanOut( //nolint:dogsled // fire-and-forget broadcast
 		ctx, "INVITE", c.nick, targetNick, targetID, 0,
-		nil, body, nil, []int64{targetID},
+		nil, body, nil, []int64{targetID}, 0,
 	)
 }
 

internal/ircserver/export_test.go

@@ -71,6 +71,11 @@ func (s *Server) Listener() net.Listener {
 	return s.listener
 }
 
+// Service returns the service the server's connections use.
+func (s *Server) Service() *service.Service {
+	return s.svc
+}
+
 // PingTimes returns how long the server's connections wait
 // with nothing read before they are sent a PING, and after it
 // before they are closed.

internal/ircserver/relay.go

@@ -198,15 +198,6 @@ func (c *Conn) deliverTextMessage(
 	from := msg.From
 	target := msg.To
 
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	// Don't echo our own messages back.
-	if from == nick {
-		return
-	}
-
 	prefix := from
 	if !strings.Contains(prefix, "!") {
 		prefix = from + "!" + from + "@*"
@@ -219,16 +210,6 @@ func (c *Conn) deliverTextMessage(
 
 // deliverJoin sends a JOIN notification.
 func (c *Conn) deliverJoin(msg *db.IRCMessage) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	// Don't echo our own JOINs (we already sent them
-	// during joinChannel).
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 	channel := msg.To
 
@@ -237,14 +218,6 @@ func (c *Conn) deliverJoin(msg *db.IRCMessage) {
 
 // deliverPart sends a PART notification.
 func (c *Conn) deliverPart(msg *db.IRCMessage, text string) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 	channel := msg.To
 
@@ -262,14 +235,6 @@ func (c *Conn) deliverNickChange(
 	msg *db.IRCMessage,
 	newNick string,
 ) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 
 	c.send(FormatMessage(prefix, "NICK", newNick))
@@ -280,14 +245,6 @@ func (c *Conn) deliverQuitMsg(
 	msg *db.IRCMessage,
 	text string,
 ) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 
 	if text != "" {
@@ -304,15 +261,6 @@ func (c *Conn) deliverTopicChange(
 	msg *db.IRCMessage,
 	text string,
 ) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	// handleTopic already echoed our own topic change.
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 	channel := msg.To
 
@@ -324,15 +272,6 @@ func (c *Conn) deliverKickMsg(
 	msg *db.IRCMessage,
 	text string,
 ) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	// handleKick already echoed our own kick.
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 	channel := msg.To
 
@@ -403,15 +342,6 @@ func (c *Conn) deliverMode(
 		return
 	}
 
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	// applyChannelModes already echoed our own mode change.
-	if msg.From == nick {
-		return
-	}
-
 	prefix := msg.From + "!" + msg.From + "@*"
 
 	params := slices.Concat(

internal/ircserver/relay_test.go

@@ -1,6 +1,7 @@
 package ircserver_test
 
 import (
+	"context"
 	"encoding/json"
 	"slices"
 	"strings"
@@ -8,6 +9,7 @@ import (
 	"time"
 
 	"sneak.berlin/go/neoirc/internal/ircserver"
+	"sneak.berlin/go/neoirc/internal/service"
 )
 
 // queueMessage queues a message for the user with nick
@@ -39,7 +41,7 @@ func (env *testEnv) queueMessage(
 		t.Fatalf("get session of %s: %v", recipient, err)
 	}
 
-	err = env.database.EnqueueToSession(ctx, sessionID, msgID)
+	err = env.database.EnqueueToSession(ctx, sessionID, msgID, 0)
 	if err != nil {
 		t.Fatalf("enqueue: %v", err)
 	}
@@ -391,3 +393,211 @@ func TestRelayOwnChangeOnce(t *testing.T) {
 		})
 	}
 }
+
+// TestRelayOwnSessionOnce checks that a command a user makes
+// from one client of their session reaches each of the
+// session's clients once: an IRC listener connection and an
+// HTTP API client. The connection that sent a command gets
+// only its own echo, and none for PRIVMSG and NOTICE, which
+// IRC does not echo.
+//
+//nolint:funlen // table-driven test
+func TestRelayOwnSessionOnce(t *testing.T) {
+	t.Parallel()
+
+	hello := json.RawMessage(`["hello"]`)
+
+	for _, step := range []struct {
+		// line is the command as alice sends it on the IRC
+		// listener.
+		line string
+		// api makes the same command for her session the way
+		// the HTTP API does.
+		api func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error
+		// echoes is how many copies alice's connection gets of
+		// line when it sends line itself.
+		echoes int
+	}{
+		{"PRIVMSG #chan :hello", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			_, err := svc.SendChannelMessage(
+				ctx, sessionID, 0, "alice", "PRIVMSG", "#chan", hello, nil,
+			)
+
+			return err
+		}, 0},
+		{"NOTICE bob :hello", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			_, err := svc.SendDirectMessage(
+				ctx, sessionID, 0, "alice", "NOTICE", "bob", hello, nil,
+			)
+
+			return err
+		}, 0},
+		{"JOIN #other", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			_, err := svc.JoinChannel(ctx, sessionID, 0, "alice", "#other", "")
+
+			return err
+		}, 1},
+		{"PART #chan :bye", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			return svc.PartChannel(ctx, sessionID, 0, "alice", "#chan", "bye")
+		}, 1},
+		{"NICK alice2", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			return svc.ChangeNick(ctx, sessionID, 0, "alice", "alice2")
+		}, 1},
+		{"TOPIC #chan :new topic", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			return svc.SetTopic(
+				ctx, sessionID, 0, "alice", "#chan", "new topic",
+			)
+		}, 1},
+		{"MODE #chan +m", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			chID, err := svc.ValidateChannelOp(ctx, sessionID, "#chan")
+			if err != nil {
+				return err
+			}
+
+			err = svc.SetChannelFlag(ctx, chID, 'm', true)
+			if err != nil {
+				return err
+			}
+
+			svc.BroadcastMode(ctx, 0, "alice", "#chan", chID, "+m")
+
+			return nil
+		}, 1},
+		{"KICK #chan bob :bye", func(
+			ctx context.Context, svc *service.Service, sessionID int64,
+		) error {
+			return svc.KickUser(
+				ctx, sessionID, 0, "alice", "#chan", "bob", "bye",
+			)
+		}, 1},
+	} {
+		command := strings.Fields(step.line)[0]
+
+		t.Run(command+" from IRC", func(t *testing.T) {
+			t.Parallel()
+
+			ircCopies, httpCopies := ownSessionCopies(t, step.line, nil)
+			if ircCopies != step.echoes || httpCopies != 1 {
+				t.Errorf("connection got %d, HTTP client got %d, want %d and 1",
+					ircCopies, httpCopies, step.echoes)
+			}
+		})
+
+		t.Run(command+" from the HTTP API", func(t *testing.T) {
+			t.Parallel()
+
+			ircCopies, httpCopies := ownSessionCopies(t, step.line, step.api)
+			if ircCopies != 1 || httpCopies != 1 {
+				t.Errorf("connection got %d, HTTP client got %d, want 1 and 1",
+					ircCopies, httpCopies)
+			}
+		})
+	}
+}
+
+// ownSessionCopies connects alice to the IRC listener and has
+// her join #chan, which bob is on too, then adds an HTTP API
+// client to her session with the password her connection set,
+// as POST /api/v1/login does. It makes the command line from
+// her connection, or with api from the HTTP API client when api
+// is not nil, and returns how many copies of it her connection
+// and her HTTP API client got.
+func ownSessionCopies(
+	t *testing.T,
+	line string,
+	api func(ctx context.Context, svc *service.Service, sessionID int64) error,
+) (int, int) {
+	t.Helper()
+
+	const password = "alicepass"
+
+	ctx := t.Context()
+	env := newTestEnv(t)
+
+	alice := env.dial(t)
+	alice.send("PASS " + password)
+	alice.register("alice")
+	// Registration stores the password before the JOIN runs.
+	alice.joinAndDrain("#chan")
+
+	bob := env.dial(t)
+	bob.register("bob")
+	bob.joinAndDrain("#chan")
+
+	sessionID, httpClientID, _, err := env.database.LoginUser(
+		ctx, "alice", password, "127.0.0.1", "localhost",
+	)
+	if err != nil {
+		t.Fatalf("log in as alice: %v", err)
+	}
+
+	var lines []string
+
+	if api == nil {
+		alice.send(line)
+
+		// Her echo comes before the reply to her next command.
+		lines = alice.sendAndExpect("PING :done", "PONG")
+	} else {
+		err = api(ctx, env.srv.Service(), sessionID)
+		if err != nil {
+			t.Fatalf("%s over the HTTP API: %v", line, err)
+		}
+	}
+
+	msgs, _, err := env.database.PollMessages(ctx, httpClientID, 0, 0)
+	if err != nil {
+		t.Fatalf("poll the HTTP API client: %v", err)
+	}
+
+	httpCopies := 0
+
+	for _, msg := range msgs {
+		if msg.Command == strings.Fields(line)[0] {
+			httpCopies++
+		}
+	}
+
+	// The relay sends a queue in order, so this arrives after any
+	// copy. It is queued by session, as NICK changes her nick.
+	endID, _, err := env.database.InsertMessage(
+		ctx, "PRIVMSG", "dave", "alice", 0, 0,
+		nil, json.RawMessage(`["the end"]`), nil,
+	)
+	if err != nil {
+		t.Fatalf("insert message: %v", err)
+	}
+
+	err = env.database.EnqueueToSession(ctx, sessionID, endID, 0)
+	if err != nil {
+		t.Fatalf("enqueue: %v", err)
+	}
+
+	env.brk.Notify(sessionID)
+
+	lines = append(lines, alice.readUntil(func(l string) bool {
+		return strings.HasSuffix(l, " :the end")
+	})...)
+
+	// A copy starts with the command and its first parameter.
+	start := " " + strings.Join(strings.Fields(line)[:2], " ")
+	ircCopies := strings.Count(strings.Join(lines, "\n"), start)
+
+	return ircCopies, httpCopies
+}

internal/service/service.go

@@ -312,7 +312,7 @@ func (s *Service) SendWallops(
 
 	_, _, err = s.FanOut(
 		ctx, irc.CmdWallops, nick, "*", 0, 0,
-		nil, body, nil, recipients,
+		nil, body, nil, recipients, 0,
 	)
 	if err != nil {
 		return fmt.Errorf("wallops: %w", err)
@@ -347,12 +347,19 @@ type DirectMsgResult struct {
 // session IDs, notifying each via the broker. toSessionID
 // and toChannelID are the recipient InsertMessage records
 // for history, 0 when there is none.
+//
+// skipClientID is the client whose queue the message is
+// not added to: the IRC listener connection that sent the
+// command, which has already shown it to its user. The HTTP
+// API passes 0, as its clients see their own commands
+// through their queues.
 func (s *Service) FanOut(
 	ctx context.Context,
 	command, from, to string,
 	toSessionID, toChannelID int64,
 	params, body, meta json.RawMessage,
 	sessionIDs []int64,
+	skipClientID int64,
 ) (int64, string, error) {
 	dbID, msgUUID, err := s.db.InsertMessage(
 		ctx, command, from, to,
@@ -363,58 +370,40 @@ func (s *Service) FanOut(
 	}
 
 	for _, sid := range sessionIDs {
-		_ = s.db.EnqueueToSession(ctx, sid, dbID)
+		_ = s.db.EnqueueToSession(ctx, sid, dbID, skipClientID)
 		s.broker.Notify(sid)
 	}
 
 	return dbID, msgUUID, nil
 }
 
-// excludeSession returns a copy of ids without the given
-// session.
-func excludeSession(
-	ids []int64,
-	exclude int64,
-) []int64 {
-	out := make([]int64, 0, len(ids))
-
-	for _, id := range ids {
-		if id != exclude {
-			out = append(out, id)
-		}
-	}
-
-	return out
-}
-
 // SendChannelMessage checks membership, bans and
 // moderation, then the hashcash stamp of a PRIVMSG to a +H
-// channel, then fans out a message to all channel members
+// channel, then fans out a message to all channel members,
-// except the sender. The stamp is checked after the other
+// the sender's session included, skipping client
-// checks so that a message they refuse does not spend it.
+// skipClientID as FanOut does. The stamp is checked after
-// Returns the database row ID, message UUID, and any error.
+// the other checks so that a message they refuse does not
-// The dbID lets callers enqueue the same message to the
+// spend it. Returns the message UUID and any error.
-// sender when echo is needed (HTTP transport).
 func (s *Service) SendChannelMessage(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	nick, command, channel string,
 	body, meta json.RawMessage,
-) (int64, string, error) {
+) (string, error) {
 	noSuchChannel := &IRCError{
 		irc.ErrNoSuchChannel, []string{channel}, msgNoSuchChannel,
 	}
 
 	chID, err := s.db.GetChannelByName(ctx, channel)
 	if err != nil {
-		return 0, "", noSuchChannel
+		return "", noSuchChannel
 	}
 
 	isMember, _ := s.db.IsChannelMember(
 		ctx, chID, sessionID,
 	)
 	if !isMember {
-		return 0, "", &IRCError{
+		return "", &IRCError{
 			irc.ErrCannotSendToChan,
 			[]string{channel},
 			"Cannot send to channel",
@@ -426,7 +415,7 @@ func (s *Service) SendChannelMessage(
 		ctx, chID, sessionID,
 	)
 	if banErr == nil && isBanned {
-		return 0, "", &IRCError{
+		return "", &IRCError{
 			irc.ErrCannotSendToChan,
 			[]string{channel},
 			"Cannot send to channel (+b)",
@@ -443,7 +432,7 @@ func (s *Service) SendChannelMessage(
 		)
 
 		if !isOp && !isVoiced {
-			return 0, "", &IRCError{
+			return "", &IRCError{
 				irc.ErrCannotSendToChan,
 				[]string{channel},
 				"Cannot send to channel (+m)",
@@ -456,35 +445,35 @@ func (s *Service) SendChannelMessage(
 			ctx, chID, channel, body, meta,
 		)
 		if err != nil {
-			return 0, "", err
+			return "", err
 		}
 	}
 
 	memberIDs, _ := s.db.GetChannelMemberIDs(ctx, chID)
-	recipients := excludeSession(memberIDs, sessionID)
 
-	dbID, uuid, fanErr := s.FanOut(
+	_, uuid, fanErr := s.FanOut(
 		ctx, command, nick, channel, 0, chID,
-		nil, body, meta, recipients,
+		nil, body, meta, memberIDs, skipClientID,
 	)
 	// The channel was deleted after the lookup above.
 	if db.IsForeignKeyConstraintError(fanErr) {
-		return 0, "", noSuchChannel
+		return "", noSuchChannel
 	}
 
 	if fanErr != nil {
-		return 0, "", fanErr
+		return "", fanErr
 	}
 
-	return dbID, uuid, nil
+	return uuid, nil
 }
 
 // SendDirectMessage validates the target and sends a
-// direct message, returning the message UUID and any away
+// direct message to the target and the sender's session,
-// message set on the target.
+// skipping client skipClientID as FanOut does, and returns
+// the message UUID and any away message set on the target.
 func (s *Service) SendDirectMessage(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	nick, command, target string,
 	body, meta json.RawMessage,
 ) (*DirectMsgResult, error) {
@@ -506,7 +495,7 @@ func (s *Service) SendDirectMessage(
 
 	_, uuid, fanErr := s.FanOut(
 		ctx, command, nick, target, targetSID, 0,
-		nil, body, meta, recipients,
+		nil, body, meta, recipients, skipClientID,
 	)
 	// The target's session was deleted after the lookup above.
 	if db.IsForeignKeyConstraintError(fanErr) {
@@ -522,11 +511,12 @@ func (s *Service) SendDirectMessage(
 
 // JoinChannel creates or joins a channel, making the
 // first joiner the operator. Fans out the JOIN to all
-// channel members. A channel name that validChannelRe
+// channel members, skipping client skipClientID as FanOut
-// does not match gets ERR_NOSUCHCHANNEL.
+// does. A channel name that validChannelRe does not match
+// gets ERR_NOSUCHCHANNEL.
 func (s *Service) JoinChannel(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	nick, channel, suppliedKey string,
 ) (*JoinResult, error) {
 	if !validChannelRe.MatchString(channel) {
@@ -549,7 +539,7 @@ func (s *Service) JoinChannel(
 
 	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
 		ctx, irc.CmdJoin, nick, channel, 0, chID,
-		nil, body, nil, memberIDs,
+		nil, body, nil, memberIDs, skipClientID,
 	)
 
 	return &JoinResult{
@@ -558,12 +548,12 @@ func (s *Service) JoinChannel(
 	}, nil
 }
 
-// PartChannel validates membership, broadcasts PART to
+// PartChannel validates membership, broadcasts PART to all
-// remaining members, removes the user, and cleans up empty
+// channel members, skipping client skipClientID as FanOut
-// channels.
+// does, removes the user, and cleans up empty channels.
 func (s *Service) PartChannel(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	nick, channel, reason string,
 ) error {
 	chID, err := s.db.GetChannelByName(ctx, channel)
@@ -587,12 +577,11 @@ func (s *Service) PartChannel(
 	}
 
 	memberIDs, _ := s.db.GetChannelMemberIDs(ctx, chID)
-	recipients := excludeSession(memberIDs, sessionID)
 	body, _ := json.Marshal([]string{reason}) //nolint:errchkjson
 
 	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
 		ctx, irc.CmdPart, nick, channel, 0, chID,
-		nil, body, nil, recipients,
+		nil, body, nil, memberIDs, skipClientID,
 	)
 
 	s.db.PartChannelAndDeleteIfEmpty(ctx, chID, sessionID) //nolint:errcheck,gosec
@@ -601,10 +590,11 @@ func (s *Service) PartChannel(
 }
 
 // SetTopic validates membership and topic-lock, sets the
-// topic, and broadcasts the change.
+// topic, and broadcasts the change to all channel members,
+// skipping client skipClientID as FanOut does.
 func (s *Service) SetTopic(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	nick, channel, topic string,
 ) error {
 	chID, err := s.db.GetChannelByName(ctx, channel)
@@ -653,18 +643,19 @@ func (s *Service) SetTopic(
 
 	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
 		ctx, irc.CmdTopic, nick, channel, 0, chID,
-		nil, body, nil, memberIDs,
+		nil, body, nil, memberIDs, skipClientID,
 	)
 
 	return nil
 }
 
 // KickUser validates operator status and target
-// membership, broadcasts the KICK, removes the target,
+// membership, broadcasts the KICK to all channel members,
-// and cleans up empty channels.
+// skipping client skipClientID as FanOut does, removes the
+// target, and cleans up empty channels.
 func (s *Service) KickUser(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	nick, channel, targetNick, reason string,
 ) error {
 	chID, err := s.db.GetChannelByName(ctx, channel)
@@ -717,7 +708,7 @@ func (s *Service) KickUser(
 
 	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
 		ctx, irc.CmdKick, nick, channel, 0, chID,
-		params, body, nil, memberIDs,
+		params, body, nil, memberIDs, skipClientID,
 	)
 
 	s.db.PartChannelAndDeleteIfEmpty(ctx, chID, targetSID) //nolint:errcheck,gosec
@@ -798,10 +789,11 @@ func (s *Service) InviteUser(
 }
 
 // ChangeNick changes a user's nickname and broadcasts the
-// change to all users sharing channels.
+// change to the user's own session and all users sharing
+// channels, skipping client skipClientID as FanOut does.
 func (s *Service) ChangeNick(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	oldNick, newNick string,
 ) error {
 	err := s.db.ChangeNick(ctx, sessionID, newNick)
@@ -822,7 +814,9 @@ func (s *Service) ChangeNick(
 		}
 	}
 
-	s.broadcastNickChange(ctx, sessionID, oldNick, newNick)
+	s.broadcastNickChange(
+		ctx, sessionID, skipClientID, oldNick, newNick,
+	)
 
 	return nil
 }
@@ -1042,9 +1036,10 @@ func (s *Service) SetChannelFlag(
 }
 
 // BroadcastMode fans out a MODE change to all channel
-// members.
+// members, skipping client skipClientID as FanOut does.
 func (s *Service) BroadcastMode(
 	ctx context.Context,
+	skipClientID int64,
 	nick, channel string,
 	chID int64,
 	modeText string,
@@ -1054,7 +1049,7 @@ func (s *Service) BroadcastMode(
 
 	_, _, _ = s.FanOut( //nolint:dogsled // fire-and-forget broadcast
 		ctx, irc.CmdMode, nick, channel, 0, chID,
-		nil, body, nil, memberIDs,
+		nil, body, nil, memberIDs, skipClientID,
 	)
 }
 
@@ -1306,11 +1301,12 @@ func (s *Service) checkChannelHashcash(
 	return nil
 }
 
-// broadcastNickChange notifies channel peers of a nick
+// broadcastNickChange notifies the user's own session,
+// except client skipClientID, and channel peers of a nick
 // change.
 func (s *Service) broadcastNickChange(
 	ctx context.Context,
-	sessionID int64,
+	sessionID, skipClientID int64,
 	oldNick, newNick string,
 ) {
 	channels, err := s.db.GetSessionChannels(
@@ -1332,7 +1328,7 @@ func (s *Service) broadcastNickChange(
 	}
 
 	// Notify the user themselves (for multi-client sync).
-	_ = s.db.EnqueueToSession(ctx, sessionID, dbID)
+	_ = s.db.EnqueueToSession(ctx, sessionID, dbID, skipClientID)
 	s.broker.Notify(sessionID)
 	notified[sessionID] = true
 
@@ -1351,7 +1347,7 @@ func (s *Service) broadcastNickChange(
 
 			notified[mid] = true
 
-			_ = s.db.EnqueueToSession(ctx, mid, dbID)
+			_ = s.db.EnqueueToSession(ctx, mid, dbID, 0)
 			s.broker.Notify(mid)
 		}
 	}

internal/service/service_test.go

@@ -168,7 +168,7 @@ func TestFanOut(t *testing.T) {
 	dbID, uuid, err := env.svc.FanOut(
 		ctx, irc.CmdPrivmsg, "alice", "#test", 0, 0,
 		nil, body, nil,
-		[]int64{sid1, sid2},
+		[]int64{sid1, sid2}, 0,
 	)
 	if err != nil {
 		t.Fatalf("FanOut: %v", err)
@@ -190,7 +190,7 @@ func TestJoinChannel(t *testing.T) {
 	sid := createSession(ctx, t, env.db, "alice")
 
 	result, err := env.svc.JoinChannel(
-		ctx, sid, "alice", "#general", "",
+		ctx, sid, 0, "alice", "#general", "",
 	)
 	if err != nil {
 		t.Fatalf("JoinChannel: %v", err)
@@ -208,7 +208,7 @@ func TestJoinChannel(t *testing.T) {
 	sid2 := createSession(ctx, t, env.db, "bob")
 
 	result2, err := env.svc.JoinChannel(
-		ctx, sid2, "bob", "#general", "",
+		ctx, sid2, 0, "bob", "#general", "",
 	)
 	if err != nil {
 		t.Fatalf("JoinChannel bob: %v", err)
@@ -230,14 +230,14 @@ func TestPartChannel(t *testing.T) {
 	sid := createSession(ctx, t, env.db, "alice")
 
 	_, err := env.svc.JoinChannel(
-		ctx, sid, "alice", "#general", "",
+		ctx, sid, 0, "alice", "#general", "",
 	)
 	if err != nil {
 		t.Fatalf("JoinChannel: %v", err)
 	}
 
 	err = env.svc.PartChannel(
-		ctx, sid, "alice", "#general", "bye",
+		ctx, sid, 0, "alice", "#general", "bye",
 	)
 	if err != nil {
 		t.Fatalf("PartChannel: %v", err)
@@ -245,7 +245,7 @@ func TestPartChannel(t *testing.T) {
 
 	// Parting a non-existent channel returns error.
 	err = env.svc.PartChannel(
-		ctx, sid, "alice", "#nonexistent", "",
+		ctx, sid, 0, "alice", "#nonexistent", "",
 	)
 	if err == nil {
 		t.Error("expected error for non-existent channel")
@@ -309,7 +309,7 @@ func joinConcurrently(
 
 		joins[i] = func() error {
 			result, err := env.svc.JoinChannel(
-				ctx, sessionID, nick, channel, "",
+				ctx, sessionID, 0, nick, channel, "",
 			)
 			results[i] = result
 
@@ -335,7 +335,7 @@ func TestConcurrentJoinsRespectUserLimit(t *testing.T) {
 		opSID := createSession(ctx, t, env.db, opNick)
 
 		created, err := env.svc.JoinChannel(
-			ctx, opSID, opNick, channel, "",
+			ctx, opSID, 0, opNick, channel, "",
 		)
 		if err != nil {
 			t.Fatalf("join %s: %v", opNick, err)
@@ -448,7 +448,7 @@ func TestJoinConcurrentWithLastPart(t *testing.T) {
 		joinerSID := createSession(ctx, t, env.db, joinerNick)
 
 		_, err := env.svc.JoinChannel(
-			ctx, leaverSID, leaverNick, channel, "",
+			ctx, leaverSID, 0, leaverNick, channel, "",
 		)
 		if err != nil {
 			t.Fatalf("join %s: %v", leaverNick, err)
@@ -457,12 +457,12 @@ func TestJoinConcurrentWithLastPart(t *testing.T) {
 		errs := runConcurrently(
 			func() error {
 				return env.svc.PartChannel(
-					ctx, leaverSID, leaverNick, channel, "",
+					ctx, leaverSID, 0, leaverNick, channel, "",
 				)
 			},
 			func() error {
 				_, joinErr := env.svc.JoinChannel(
-					ctx, joinerSID, joinerNick, channel, "",
+					ctx, joinerSID, 0, joinerNick, channel, "",
 				)
 
 				return joinErr
@@ -513,7 +513,7 @@ func TestJoinConcurrentWithLastQuit(t *testing.T) {
 		joinerSID := createSession(ctx, t, env.db, joinerNick)
 
 		created, err := env.svc.JoinChannel(
-			ctx, leaverSID, leaverNick, channel, "",
+			ctx, leaverSID, 0, leaverNick, channel, "",
 		)
 		if err != nil {
 			t.Fatalf("join %s: %v", leaverNick, err)
@@ -545,7 +545,7 @@ func TestJoinConcurrentWithLastQuit(t *testing.T) {
 					)
 
 					joined, joinErr = env.svc.JoinChannel(
-						ctx, joinerSID, joinerNick, channel, "",
+						ctx, joinerSID, 0, joinerNick, channel, "",
 					)
 					if !errors.As(joinErr, &ircErr) ||
 						ircErr.Code != irc.ErrBadChannelKey {
@@ -592,7 +592,7 @@ func TestQuitQueuedAheadOfNewNickHoldersJoin(t *testing.T) {
 		quitterSID := createSession(ctx, t, env.db, nick)
 
 		for _, channel := range []string{crowd, shared} {
-			_, err := env.svc.JoinChannel(ctx, quitterSID, nick, channel, "")
+			_, err := env.svc.JoinChannel(ctx, quitterSID, 0, nick, channel, "")
 			if err != nil {
 				t.Fatalf("join %s: %v", channel, err)
 			}
@@ -602,7 +602,7 @@ func TestQuitQueuedAheadOfNewNickHoldersJoin(t *testing.T) {
 			memberNick := fmt.Sprintf("crowd%dx%d", trial, member)
 			memberSID := createSession(ctx, t, env.db, memberNick)
 
-			_, err := env.svc.JoinChannel(ctx, memberSID, memberNick, crowd, "")
+			_, err := env.svc.JoinChannel(ctx, memberSID, 0, memberNick, crowd, "")
 			if err != nil {
 				t.Fatalf("join %s: %v", memberNick, err)
 			}
@@ -617,7 +617,7 @@ func TestQuitQueuedAheadOfNewNickHoldersJoin(t *testing.T) {
 			t.Fatalf("create session %s: %v", watcherNick, err)
 		}
 
-		_, err = env.svc.JoinChannel(ctx, watcherSID, watcherNick, shared, "")
+		_, err = env.svc.JoinChannel(ctx, watcherSID, 0, watcherNick, shared, "")
 		if err != nil {
 			t.Fatalf("join %s: %v", watcherNick, err)
 		}
@@ -678,7 +678,7 @@ func takeNickAndJoin(
 			return err
 		}
 
-		_, err = env.svc.JoinChannel(ctx, sessionID, nick, channel, "")
+		_, err = env.svc.JoinChannel(ctx, sessionID, 0, nick, channel, "")
 
 		return err
 	}
@@ -710,7 +710,7 @@ func TestJoinUsesUpInvite(t *testing.T) {
 	opSID := createSession(ctx, t, env.db, "op")
 	guestSID := createSession(ctx, t, env.db, "guest")
 
-	created, err := env.svc.JoinChannel(ctx, opSID, "op", channel, "")
+	created, err := env.svc.JoinChannel(ctx, opSID, 0, "op", channel, "")
 	if err != nil {
 		t.Fatalf("join op: %v", err)
 	}
@@ -725,17 +725,17 @@ func TestJoinUsesUpInvite(t *testing.T) {
 		t.Fatalf("invite guest: %v", err)
 	}
 
-	_, err = env.svc.JoinChannel(ctx, guestSID, "guest", channel, "")
+	_, err = env.svc.JoinChannel(ctx, guestSID, 0, "guest", channel, "")
 	if err != nil {
 		t.Fatalf("invited join: %v", err)
 	}
 
-	err = env.svc.PartChannel(ctx, guestSID, "guest", channel, "")
+	err = env.svc.PartChannel(ctx, guestSID, 0, "guest", channel, "")
 	if err != nil {
 		t.Fatalf("part guest: %v", err)
 	}
 
-	_, err = env.svc.JoinChannel(ctx, guestSID, "guest", channel, "")
+	_, err = env.svc.JoinChannel(ctx, guestSID, 0, "guest", channel, "")
 
 	var ircErr *service.IRCError
 	if !errors.As(err, &ircErr) || ircErr.Code != irc.ErrInviteOnlyChan {
@@ -754,7 +754,7 @@ func TestJoinRefusedByHostmaskBan(t *testing.T) {
 
 	opSID := createSession(ctx, t, env.db, "op")
 
-	created, err := env.svc.JoinChannel(ctx, opSID, "op", channel, "")
+	created, err := env.svc.JoinChannel(ctx, opSID, 0, "op", channel, "")
 	if err != nil {
 		t.Fatalf("join op: %v", err)
 	}
@@ -773,7 +773,7 @@ func TestJoinRefusedByHostmaskBan(t *testing.T) {
 		t.Fatalf("create session guest: %v", err)
 	}
 
-	_, err = env.svc.JoinChannel(ctx, guestSID, "guest", channel, "")
+	_, err = env.svc.JoinChannel(ctx, guestSID, 0, "guest", channel, "")
 
 	var ircErr *service.IRCError
 	if !errors.As(err, &ircErr) || ircErr.Code != irc.ErrBannedFromChan {
@@ -793,17 +793,17 @@ func TestPartDeletesChannelOnlyWhenEmpty(t *testing.T) {
 	aliceSID := createSession(ctx, t, env.db, "alice")
 	bobSID := createSession(ctx, t, env.db, "bob")
 
-	_, err := env.svc.JoinChannel(ctx, aliceSID, "alice", channel, "")
+	_, err := env.svc.JoinChannel(ctx, aliceSID, 0, "alice", channel, "")
 	if err != nil {
 		t.Fatalf("join alice: %v", err)
 	}
 
-	_, err = env.svc.JoinChannel(ctx, bobSID, "bob", channel, "")
+	_, err = env.svc.JoinChannel(ctx, bobSID, 0, "bob", channel, "")
 	if err != nil {
 		t.Fatalf("join bob: %v", err)
 	}
 
-	err = env.svc.PartChannel(ctx, aliceSID, "alice", channel, "")
+	err = env.svc.PartChannel(ctx, aliceSID, 0, "alice", channel, "")
 	if err != nil {
 		t.Fatalf("part alice: %v", err)
 	}
@@ -818,7 +818,7 @@ func TestPartDeletesChannelOnlyWhenEmpty(t *testing.T) {
 		t.Fatal("bob is not on the channel after alice parted")
 	}
 
-	err = env.svc.PartChannel(ctx, bobSID, "bob", channel, "")
+	err = env.svc.PartChannel(ctx, bobSID, 0, "bob", channel, "")
 	if err != nil {
 		t.Fatalf("part bob: %v", err)
 	}
@@ -839,12 +839,12 @@ func TestKickOfLastMemberDeletesChannel(t *testing.T) {
 
 	sid := createSession(ctx, t, env.db, "alice")
 
-	_, err := env.svc.JoinChannel(ctx, sid, "alice", channel, "")
+	_, err := env.svc.JoinChannel(ctx, sid, 0, "alice", channel, "")
 	if err != nil {
 		t.Fatalf("join alice: %v", err)
 	}
 
-	err = env.svc.KickUser(ctx, sid, "alice", channel, "alice", "")
+	err = env.svc.KickUser(ctx, sid, 0, "alice", channel, "alice", "")
 	if err != nil {
 		t.Fatalf("kick alice: %v", err)
 	}
@@ -863,14 +863,14 @@ func TestSendChannelMessage(t *testing.T) {
 	sid2 := createSession(ctx, t, env.db, "bob")
 
 	_, err := env.svc.JoinChannel(
-		ctx, sid1, "alice", "#chat", "",
+		ctx, sid1, 0, "alice", "#chat", "",
 	)
 	if err != nil {
 		t.Fatalf("join alice: %v", err)
 	}
 
 	_, err = env.svc.JoinChannel(
-		ctx, sid2, "bob", "#chat", "",
+		ctx, sid2, 0, "bob", "#chat", "",
 	)
 	if err != nil {
 		t.Fatalf("join bob: %v", err)
@@ -878,18 +878,14 @@ func TestSendChannelMessage(t *testing.T) {
 
 	body, _ := json.Marshal([]string{"hello world"}) //nolint:errchkjson
 
-	dbID, uuid, err := env.svc.SendChannelMessage(
+	uuid, err := env.svc.SendChannelMessage(
-		ctx, sid1, "alice",
+		ctx, sid1, 0, "alice",
 		irc.CmdPrivmsg, "#chat", body, nil,
 	)
 	if err != nil {
 		t.Fatalf("SendChannelMessage: %v", err)
 	}
 
-	if dbID == 0 {
-		t.Error("expected non-zero dbID")
-	}
-
 	if uuid == "" {
 		t.Error("expected non-empty UUID")
 	}
@@ -897,8 +893,8 @@ func TestSendChannelMessage(t *testing.T) {
 	// Non-member cannot send.
 	sid3 := createSession(ctx, t, env.db, "charlie")
 
-	_, _, err = env.svc.SendChannelMessage(
+	_, err = env.svc.SendChannelMessage(
-		ctx, sid3, "charlie",
+		ctx, sid3, 0, "charlie",
 		irc.CmdPrivmsg, "#chat", body, nil,
 	)
 	if err == nil {
@@ -914,14 +910,14 @@ func TestBroadcastQuit(t *testing.T) {
 	sid2 := createSession(ctx, t, env.db, "bob")
 
 	_, err := env.svc.JoinChannel(
-		ctx, sid1, "alice", "#room", "",
+		ctx, sid1, 0, "alice", "#room", "",
 	)
 	if err != nil {
 		t.Fatalf("join alice: %v", err)
 	}
 
 	_, err = env.svc.JoinChannel(
-		ctx, sid2, "bob", "#room", "",
+		ctx, sid2, 0, "bob", "#room", "",
 	)
 	if err != nil {
 		t.Fatalf("join bob: %v", err)
@@ -963,7 +959,7 @@ func TestSendDirectMessageTargetQuits(t *testing.T) {
 	body, _ := json.Marshal([]string{"hi"}) //nolint:errchkjson
 
 	_, err = env.svc.SendDirectMessage(
-		ctx, sid, "alice", irc.CmdPrivmsg, "bob", body, nil,
+		ctx, sid, 0, "alice", irc.CmdPrivmsg, "bob", body, nil,
 	)
 
 	var ircErr *service.IRCError
@@ -983,7 +979,7 @@ func TestSendChannelMessageChannelDeleted(t *testing.T) {
 
 	sid := createSession(ctx, t, env.db, "alice")
 
-	_, err := env.svc.JoinChannel(ctx, sid, "alice", "#gone", "")
+	_, err := env.svc.JoinChannel(ctx, sid, 0, "alice", "#gone", "")
 	if err != nil {
 		t.Fatalf("join alice: %v", err)
 	}
@@ -1000,8 +996,8 @@ func TestSendChannelMessageChannelDeleted(t *testing.T) {
 
 	body, _ := json.Marshal([]string{"hi"}) //nolint:errchkjson
 
-	_, _, err = env.svc.SendChannelMessage(
+	_, err = env.svc.SendChannelMessage(
-		ctx, sid, "alice", irc.CmdPrivmsg, "#gone", body, nil,
+		ctx, sid, 0, "alice", irc.CmdPrivmsg, "#gone", body, nil,
 	)
 
 	var ircErr *service.IRCError
@@ -1019,14 +1015,14 @@ func TestSendChannelMessage_Moderated(t *testing.T) {
 	sid2 := createSession(ctx, t, env.db, "bob")
 
 	result, err := env.svc.JoinChannel(
-		ctx, sid1, "alice", "#modchat", "",
+		ctx, sid1, 0, "alice", "#modchat", "",
 	)
 	if err != nil {
 		t.Fatalf("join alice: %v", err)
 	}
 
 	_, err = env.svc.JoinChannel(
-		ctx, sid2, "bob", "#modchat", "",
+		ctx, sid2, 0, "bob", "#modchat", "",
 	)
 	if err != nil {
 		t.Fatalf("join bob: %v", err)
@@ -1039,8 +1035,8 @@ func TestSendChannelMessage_Moderated(t *testing.T) {
 	body, _ := json.Marshal([]string{"test"}) //nolint:errchkjson
 
 	// Bob (non-op, non-voiced) should fail to send.
-	_, _, err = env.svc.SendChannelMessage(
+	_, err = env.svc.SendChannelMessage(
-		ctx, sid2, "bob",
+		ctx, sid2, 0, "bob",
 		irc.CmdPrivmsg, "#modchat", body, nil,
 	)
 	if err == nil {
@@ -1048,8 +1044,8 @@ func TestSendChannelMessage_Moderated(t *testing.T) {
 	}
 
 	// Alice (operator) should succeed.
-	_, _, err = env.svc.SendChannelMessage(
+	_, err = env.svc.SendChannelMessage(
-		ctx, sid1, "alice",
+		ctx, sid1, 0, "alice",
 		irc.CmdPrivmsg, "#modchat", body, nil,
 	)
 	if err != nil {
@@ -1074,7 +1070,7 @@ func TestRefusedChannelMessageLeavesStampUnspent(t *testing.T) {
 		refuse func(ctx context.Context, env *testEnv, chID, bobSID int64) error
 	}{
 		{"not a member", func(ctx context.Context, env *testEnv, _, bobSID int64) error {
-			return env.svc.PartChannel(ctx, bobSID, "bob", channel, "")
+			return env.svc.PartChannel(ctx, bobSID, 0, "bob", channel, "")
 		}},
 		{"banned", func(ctx context.Context, env *testEnv, chID, _ int64) error {
 			return env.db.AddChannelBan(ctx, chID, "bob!*@*", "alice")
@@ -1094,12 +1090,12 @@ func TestRefusedChannelMessageLeavesStampUnspent(t *testing.T) {
 			aliceSID := createSession(ctx, t, env.db, "alice")
 			bobSID := createSession(ctx, t, env.db, "bob")
 
-			joined, err := env.svc.JoinChannel(ctx, aliceSID, "alice", channel, "")
+			joined, err := env.svc.JoinChannel(ctx, aliceSID, 0, "alice", channel, "")
 			if err != nil {
 				t.Fatalf("join alice: %v", err)
 			}
 
-			_, err = env.svc.JoinChannel(ctx, bobSID, "bob", channel, "")
+			_, err = env.svc.JoinChannel(ctx, bobSID, 0, "bob", channel, "")
 			if err != nil {
 				t.Fatalf("join bob: %v", err)
 			}
@@ -1119,8 +1115,8 @@ func TestRefusedChannelMessageLeavesStampUnspent(t *testing.T) {
 			)
 			meta, _ := json.Marshal(map[string]string{"hashcash": stamp})
 
-			_, _, err = env.svc.SendChannelMessage(
+			_, err = env.svc.SendChannelMessage(
-				ctx, bobSID, "bob", irc.CmdPrivmsg, channel, body, meta,
+				ctx, bobSID, 0, "bob", irc.CmdPrivmsg, channel, body, meta,
 			)
 
 			var ircErr *service.IRCError
@@ -1129,8 +1125,8 @@ func TestRefusedChannelMessageLeavesStampUnspent(t *testing.T) {
 				t.Fatalf("bob: want ERR_CANNOTSENDTOCHAN, got %v", err)
 			}
 
-			_, _, err = env.svc.SendChannelMessage(
+			_, err = env.svc.SendChannelMessage(
-				ctx, aliceSID, "alice", irc.CmdPrivmsg, channel, body, meta,
+				ctx, aliceSID, 0, "alice", irc.CmdPrivmsg, channel, body, meta,
 			)
 			if err != nil {
 				t.Fatalf("alice with the same stamp: %v", err)