Show neoirc-cli's own messages, joins and parts from the server's events (closes #186)

neoirc-cli wrote its own line when it sent a message, joined or parted,
and ignored the server's event for its own nick, except a JOIN, so a
join showed twice and what the session did from another client never
showed. The HTTP API queues these events to every client of the
session, so the CLI now writes no line of its own when it sends and
shows the event as it shows anyone else's. A direct message the user
sent goes in the recipient's buffer. The user's own part does not mark
the channel unread, as the user has just left it.

Model: opus-5-5

README.md

@@ -180,7 +180,7 @@ For users who want to access the same session from multiple devices:
 - **Set password via IRC PASS command**: the authenticated client sends
   `POST /api/v1/messages` with `{"command":"PASS","body":["mypassword"]}`. The
   server hashes the password with bcrypt and stores it on the session. Password
-  must be at least 8 characters.
+  must be 8 to 72 bytes.
 - **Login from another client**: `POST /api/v1/login` with nick and password →
   server verifies the password, creates a new client for the existing session,
   and sets an auth cookie. Channel memberships are shared; the new client gets
@@ -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
-  DMs and the channel messages it sends over the HTTP API, to every client queue
-  for that user session. Replies to a command (numerics) go only to the client
-  that sent it.
+- The server fans out messages and events from other users to every client queue
+  for that user session.
+- When the user sends a `PRIVMSG`, `NOTICE`, `JOIN`, `PART`, `NICK`, `TOPIC`,
+  `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 HTTP response confirms the part. (The IRC listener echoes the PART to its
-  own connection.)
+- The PART event goes to every channel member, the departing user's own clients
+  included. (An IRC listener connection that sends a PART echoes it itself.)
 - 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.
@@ -835,10 +839,11 @@ Set a password on the current session, enabling multi-client login via
 
 **Behavior:**
 
-- `body[0]` is the password. Must be at least 8 characters.
+- `body[0]` is the password. Must be 8 to 72 bytes; bcrypt cannot hash a longer
+  one.
 - On success, the server responds with `{"status": "ok"}`.
-- If the password is too short or missing, the server sends ERR_NEEDMOREPARAMS
-  (461) via the message queue.
+- If the password is too short, too long or missing, the server sends
+  ERR_NEEDMOREPARAMS (461) via the message queue.
 - Calling PASS again overwrites the previous password.
 - Once a password is set, `POST /api/v1/login` can be used with the nick and
   password to create additional clients on the same session.
@@ -1018,9 +1023,8 @@ On the IRC listener, `MODE #channel <modes> [values...]` takes several letters
 in one string, e.g. `MODE #general +mt-i` or `MODE #general +ov alice bob`. It
 accepts `i`, `m`, `n`, `s`, `t`, `o` and `v` (with a nick) and `H` (with bits
 from 1 to 40 when setting), but not `b`, `k` or `l`. A letter whose value is
-missing is skipped. The changes made are echoed to the operator's connection and
-also sent to every channel member, the operator included, as one `MODE` line,
-e.g. `+o-v alice bob`.
+missing is skipped. The changes made are sent to every channel member as one
+`MODE` line, e.g. `+o-v alice bob`; the operator gets that line once.
 
 **Channel errors:**
 
@@ -1404,7 +1408,8 @@ Include the hashcash stamp in the `meta` field:
 **Server validation:** The server checks that the stamp is well-formed, meets
 the required difficulty, is bound to the correct channel and message body, has a
 recent date, and has not been previously used. Spent stamps are cached for 1
-year to prevent replay attacks.
+year to prevent replay attacks. The stamp is checked after membership, bans and
+`+m`, so a message refused for one of those does not spend it.
 
 **Error responses:** If the channel requires hashcash and the stamp is missing,
 invalid, or replayed, the server returns `ERR_CANNOTSENDTOCHAN (404)` with a
@@ -2677,9 +2682,11 @@ IRC_LISTEN_ADDR: ""
 
 - **Wire format**: CR-LF delimited lines, max 512 bytes per line
 - **Connection registration**: Clients must send `NICK` and `USER` to register.
-  An optional `PASS` before registration sets the session password (minimum 8
-  characters). Registering creates a session without a hashcash stamp; closing
-  the connection ends the session, as `QUIT` does.
+  An optional `PASS` before registration sets the session password (8 to 72
+  bytes); one outside that range is refused with a `NOTICE` once registration
+  completes, as `PASS` after registration is. Registering creates a session
+  without a hashcash stamp; closing the connection ends the session, as `QUIT`
+  does.
 - **PING**: a connection that sends nothing for 90 seconds is sent a `PING`, and
   is closed if it sends nothing in the 30 seconds after that; any line, such as
   the client's `PONG`, starts both waits again.
@@ -2716,7 +2723,9 @@ Each line of a multi-line `body` reaches an IRC listener user as its own
 is sent, so it cannot start a line of its own. A mode change made over the HTTP
 API reaches IRC listener members as an IRC `MODE` line with its value as a
 separate parameter, e.g. `MODE #general +k secretpass` or
-`MODE #general +o bob`.
+`MODE #general +o bob`. An `INVITE` from either transport reaches the invited
+IRC listener user as an IRC `INVITE` line from the inviter, e.g.
+`:alice!alice@* INVITE bob #general`.
 
 ### Docker Usage
 
@@ -3084,6 +3093,10 @@ limits that punish shared networks.
     - Stamp has not been used before (replay prevention; the spent stamps are
       kept in memory, so a restart forgets them)
 
+    The stamp is spent only when the session is created. A request refused with
+    400 or 409 leaves it unspent, and the client can send the same stamp again
+    with another nick or username.
+
 ### Stamp Format
 
 Standard hashcash format:
@@ -3156,12 +3169,13 @@ creating one session pays once and keeps their session.
 ### Why Hashcash and Not Rate Limits?
 
 - **Little state to track**: No IP tables, no token buckets, no sliding windows.
-  The server verifies a single hash and remembers the stamps already spent.
+  The server hashes the stamp and remembers the stamps already spent.
 - **Works through NATs and proxies**: Doesn't punish shared IPs (university
   campuses, corporate networks, Tor exits). Every client computes their own
   proof independently.
 - **Cost falls on the requester**: The server's verification cost is constant
-  (one SHA-256 hash) regardless of difficulty. Only the client does more work.
+  regardless of difficulty: at most two SHA-256 hashes of the stamp per session
+  request, one to check it and one to spend it. Only the client does more work.
 - **Fits the "no accounts" philosophy**: Proof-of-work is the cost of entry. No
   registration, no email, no phone number, no CAPTCHA. Just compute.
 - **Language-agnostic**: SHA-256 is available in every programming language. The

internal/cli/api/client.go

@@ -250,7 +250,7 @@ func (client *Client) ListChannels() (
 // GetMembers returns members of a channel.
 func (client *Client) GetMembers(
 	channel string,
-) ([]string, error) {
+) ([]Member, error) {
 	name := strings.TrimPrefix(channel, "#")
 
 	data, err := client.do(
@@ -263,7 +263,7 @@ func (client *Client) GetMembers(
 		return nil, err
 	}
 
-	var members []string
+	var members []Member
 
 	err = json.Unmarshal(data, &members)
 	if err != nil {

internal/cli/api/client_test.go

@@ -2,18 +2,28 @@ package neoircapi_test
 
 import (
 	"context"
+	"encoding/json"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"reflect"
+	"slices"
+	"strconv"
 	"strings"
 	"testing"
 
 	api "sneak.berlin/go/neoirc/internal/cli/api"
+	"sneak.berlin/go/neoirc/internal/hashcash"
 )
 
-const cookieValue = "opaque-value"
+const (
+	cookieValue = "opaque-value"
+	testNick    = "alice"
+	testChannel = "#general"
+)
 
 // newSessionServer starts a plain-HTTP server that, like
 // neoircd, sets a Secure auth cookie when a session is
@@ -24,10 +34,16 @@ func newSessionServer(t *testing.T) *httptest.Server {
 
 	mux := http.NewServeMux()
 
+	// Without hashcash the server sends no hashcash_bits.
 	mux.HandleFunc("GET /api/v1/server", func(
 		writer http.ResponseWriter, _ *http.Request,
 	) {
-		_, _ = io.WriteString(writer, `{}`)
+		_, _ = io.WriteString(writer, `{
+			"name": "My NeoIRC Server",
+			"version": "0.1.0",
+			"motd": "Welcome! Be nice.",
+			"users": 42
+		}`)
 	})
 
 	mux.HandleFunc("POST /api/v1/session", func(
@@ -56,9 +72,14 @@ func newSessionServer(t *testing.T) *httptest.Server {
 			return
 		}
 
-		_, _ = io.WriteString(
-			writer, `{"id":1,"nick":"alice","channels":[]}`,
-		)
+		_, _ = io.WriteString(writer, `{
+			"id": 1,
+			"nick": "alice",
+			"channels": [
+				{"id": 1, "name": "#general", "topic": "Welcome!"},
+				{"id": 2, "name": "#dev", "topic": ""}
+			]
+		}`)
 	})
 
 	server := httptest.NewServer(mux)
@@ -67,6 +88,344 @@ func newSessionServer(t *testing.T) *httptest.Server {
 	return server
 }
 
+// newClientForPath starts a server that answers GET path with
+// body, and returns a client for it.
+func newClientForPath(t *testing.T, path, body string) *api.Client {
+	t.Helper()
+
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("GET "+path, func(
+		writer http.ResponseWriter, _ *http.Request,
+	) {
+		_, _ = io.WriteString(writer, body)
+	})
+
+	server := httptest.NewServer(mux)
+	t.Cleanup(server.Close)
+
+	return api.NewClient(server.URL)
+}
+
+func TestGetStateDecodesFields(t *testing.T) {
+	t.Parallel()
+
+	client := api.NewClient(newSessionServer(t).URL)
+
+	_, err := client.CreateSession(testNick)
+	if err != nil {
+		t.Fatalf("create session: %v", err)
+	}
+
+	state, err := client.GetState()
+	if err != nil {
+		t.Fatalf("state: %v", err)
+	}
+
+	want := api.StateResponse{
+		ID:   1,
+		Nick: testNick,
+		Channels: []api.Channel{
+			{Name: testChannel, Topic: "Welcome!"},
+			{Name: "#dev", Topic: ""},
+		},
+	}
+	if !reflect.DeepEqual(*state, want) {
+		t.Fatalf("state: got %+v, want %+v", *state, want)
+	}
+}
+
+func TestGetServerInfoDecodesFields(t *testing.T) {
+	t.Parallel()
+
+	client := newClientForPath(t, "/api/v1/server", `{
+		"name": "My NeoIRC Server",
+		"version": "0.1.0",
+		"motd": "Welcome! Be nice.",
+		"users": 42,
+		"hashcash_bits": 20
+	}`)
+
+	info, err := client.GetServerInfo()
+	if err != nil {
+		t.Fatalf("server info: %v", err)
+	}
+
+	want := api.ServerInfo{
+		Name:         "My NeoIRC Server",
+		MOTD:         "Welcome! Be nice.",
+		Version:      "0.1.0",
+		HashcashBits: 20,
+	}
+	if *info != want {
+		t.Fatalf("server info: got %+v, want %+v", *info, want)
+	}
+}
+
+// TestCreateSessionSendsNickAndStamp serves a server that, like
+// neoircd with hashcash on, advertises hashcash_bits and creates
+// the session only for a pow_token the server's validator in
+// internal/hashcash accepts.
+func TestCreateSessionSendsNickAndStamp(t *testing.T) {
+	t.Parallel()
+
+	const (
+		serverName = "My NeoIRC Server"
+		stampBits  = 8
+		sessionID  = 7
+	)
+
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("GET /api/v1/server", func(
+		writer http.ResponseWriter, _ *http.Request,
+	) {
+		_, _ = fmt.Fprintf(writer, `{
+			"name": %q,
+			"version": "0.1.0",
+			"motd": "Welcome! Be nice.",
+			"users": 42,
+			"hashcash_bits": %d
+		}`, serverName, stampBits)
+	})
+
+	validator := hashcash.NewValidator(serverName)
+
+	mux.HandleFunc("POST /api/v1/session", func(
+		writer http.ResponseWriter, request *http.Request,
+	) {
+		// Decoded with the field names handleCreateSession uses.
+		var payload struct {
+			Nick     string `json:"nick"`
+			Hashcash string `json:"pow_token"` //nolint:tagliatelle
+		}
+
+		err := json.NewDecoder(request.Body).Decode(&payload)
+		if err != nil {
+			writer.WriteHeader(http.StatusBadRequest)
+
+			return
+		}
+
+		err = validator.Claim(payload.Hashcash, stampBits)
+		if err != nil {
+			writer.WriteHeader(http.StatusPaymentRequired)
+
+			return
+		}
+
+		writer.WriteHeader(http.StatusCreated)
+
+		_ = json.NewEncoder(writer).Encode(map[string]any{
+			"id":   sessionID,
+			"nick": payload.Nick,
+		})
+	})
+
+	server := httptest.NewServer(mux)
+	t.Cleanup(server.Close)
+
+	session, err := api.NewClient(server.URL).CreateSession(testNick)
+	if err != nil {
+		t.Fatalf("create session: %v", err)
+	}
+
+	want := api.SessionResponse{ID: sessionID, Nick: testNick}
+	if *session != want {
+		t.Fatalf("session: got %+v, want %+v", *session, want)
+	}
+}
+
+func TestListChannelsDecodesNamesAndTopics(t *testing.T) {
+	t.Parallel()
+
+	client := newClientForPath(t, "/api/v1/channels", `[
+		{"id": 1, "name": "#general", "topic": "Welcome!"},
+		{"id": 2, "name": "#dev", "topic": "Development discussion"}
+	]`)
+
+	channels, err := client.ListChannels()
+	if err != nil {
+		t.Fatalf("list channels: %v", err)
+	}
+
+	want := []api.Channel{
+		{Name: testChannel, Topic: "Welcome!"},
+		{Name: "#dev", Topic: "Development discussion"},
+	}
+	if !slices.Equal(channels, want) {
+		t.Fatalf("channels: got %+v, want %+v", channels, want)
+	}
+}
+
+func TestGetMembersDecodesMemberObjects(t *testing.T) {
+	t.Parallel()
+
+	client := newClientForPath(t, "/api/v1/channels/general/members", `[
+		{
+			"id": 1, "nick": "alice", "username": "alice",
+			"hostname": "host.example.com",
+			"isOperator": true, "isVoiced": false,
+			"lastSeen": "2026-02-10T20:00:00Z"
+		},
+		{
+			"id": 2, "nick": "bob", "username": "bob",
+			"hostname": "host.example.com",
+			"isOperator": false, "isVoiced": true,
+			"lastSeen": "2026-02-10T20:00:00Z"
+		},
+		{
+			"id": 3, "nick": "Carol", "username": "carol",
+			"hostname": "host.example.com",
+			"isOperator": false, "isVoiced": false,
+			"lastSeen": "2026-02-10T20:00:00Z"
+		}
+	]`)
+
+	members, err := client.GetMembers(testChannel)
+	if err != nil {
+		t.Fatalf("get members: %v", err)
+	}
+
+	want := []api.Member{
+		{Nick: testNick, IsOperator: true, IsVoiced: false},
+		{Nick: "bob", IsOperator: false, IsVoiced: true},
+		{Nick: "Carol", IsOperator: false, IsVoiced: false},
+	}
+	if !slices.Equal(members, want) {
+		t.Fatalf("members: got %+v, want %+v", members, want)
+	}
+}
+
+// TestPollMessagesAdvancesCursor serves the queue as the server
+// does: entries after the cursor, and last_id as the new cursor.
+func TestPollMessagesAdvancesCursor(t *testing.T) {
+	t.Parallel()
+
+	const lastQueueID = 42
+
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("GET /api/v1/messages", func(
+		writer http.ResponseWriter, request *http.Request,
+	) {
+		after := request.URL.Query().Get("after")
+		if after == strconv.Itoa(lastQueueID) {
+			_, _ = io.WriteString(
+				writer, `{"messages": [], "last_id": 42}`,
+			)
+
+			return
+		}
+
+		_, _ = io.WriteString(writer, `{
+			"messages": [{
+				"id": "b7c8210f-849c-4b90-9ee8-d99c8889358e",
+				"command": "PRIVMSG",
+				"from": "alice",
+				"to": "#general",
+				"body": ["hello world"],
+				"ts": "2026-02-10T20:00:01.234567891Z",
+				"meta": {}
+			}],
+			"last_id": 42
+		}`)
+	})
+
+	server := httptest.NewServer(mux)
+	t.Cleanup(server.Close)
+
+	client := api.NewClient(server.URL)
+
+	first, err := client.PollMessages(0, 0)
+	if err != nil {
+		t.Fatalf("first poll: %v", err)
+	}
+
+	if first.LastID != lastQueueID || len(first.Messages) != 1 {
+		t.Fatalf(
+			"first poll: got last ID %d and %d messages, "+
+				"want %d and 1",
+			first.LastID, len(first.Messages), lastQueueID,
+		)
+	}
+
+	second, err := client.PollMessages(first.LastID, 0)
+	if err != nil {
+		t.Fatalf("second poll: %v", err)
+	}
+
+	if len(second.Messages) != 0 {
+		t.Fatalf(
+			"second poll: got %d messages again, want none",
+			len(second.Messages),
+		)
+	}
+}
+
+// TestPollMessagesDecodesMessageFields serves a relayed PRIVMSG
+// with the sender's meta and a numeric, as the server queues
+// them.
+func TestPollMessagesDecodesMessageFields(t *testing.T) {
+	t.Parallel()
+
+	client := newClientForPath(t, "/api/v1/messages", `{
+		"messages": [
+			{
+				"id": "b7c8210f-849c-4b90-9ee8-d99c8889358e",
+				"command": "PRIVMSG",
+				"from": "alice",
+				"to": "#general",
+				"body": ["signed message"],
+				"ts": "2026-02-10T20:00:01.234567891Z",
+				"meta": {"sig": "base64...", "alg": "ed25519"}
+			},
+			{
+				"id": "7f5a04f8-eab4-4d2e-be55-f5cfcfaf43c5",
+				"command": "RPL_LUSEROP",
+				"code": 252,
+				"from": "neoirc",
+				"to": "alice",
+				"params": ["0"],
+				"body": ["operator(s) online"],
+				"ts": "2026-02-10T20:00:02Z",
+				"meta": {}
+			}
+		],
+		"last_id": 42
+	}`)
+
+	result, err := client.PollMessages(0, 0)
+	if err != nil {
+		t.Fatalf("poll: %v", err)
+	}
+
+	want := []api.Message{
+		{
+			ID:      "b7c8210f-849c-4b90-9ee8-d99c8889358e",
+			Command: "PRIVMSG",
+			From:    testNick,
+			To:      testChannel,
+			Body:    []any{"signed message"},
+			TS:      "2026-02-10T20:00:01.234567891Z",
+			Meta:    map[string]any{"sig": "base64...", "alg": "ed25519"},
+		},
+		{
+			ID:      "7f5a04f8-eab4-4d2e-be55-f5cfcfaf43c5",
+			Command: "RPL_LUSEROP",
+			From:    "neoirc",
+			To:      testNick,
+			Params:  []string{"0"},
+			Body:    []any{"operator(s) online"},
+			TS:      "2026-02-10T20:00:02Z",
+			Meta:    map[string]any{},
+		},
+	}
+	if !reflect.DeepEqual(result.Messages, want) {
+		t.Fatalf("messages: got %+v, want %+v", result.Messages, want)
+	}
+}
+
 func TestClientKeepsSessionOverPlainHTTPOnLocalhost(t *testing.T) {
 	t.Parallel()
 
@@ -85,7 +444,7 @@ func TestClientKeepsSessionOverPlainHTTPOnLocalhost(t *testing.T) {
 				"http://" + net.JoinHostPort(host, serverURL.Port()),
 			)
 
-			_, err := client.CreateSession("alice")
+			_, err := client.CreateSession(testNick)
 			if err != nil {
 				t.Fatalf("create session: %v", err)
 			}
@@ -118,7 +477,7 @@ func TestClientWithholdsCookieOverPlainHTTPFromOtherHosts(t *testing.T) {
 		},
 	}
 
-	_, err := client.CreateSession("alice")
+	_, err := client.CreateSession(testNick)
 	if err != nil {
 		t.Fatalf("create session: %v", err)
 	}

internal/cli/api/types.go

@@ -16,9 +16,9 @@ type SessionResponse struct {
 
 // StateResponse is the response from GET /api/v1/state.
 type StateResponse struct {
-	ID       int64    `json:"id"`
-	Nick     string   `json:"nick"`
-	Channels []string `json:"channels"`
+	ID       int64     `json:"id"`
+	Nick     string    `json:"nick"`
+	Channels []Channel `json:"channels"`
 }
 
 // Message represents a neoirc message envelope.
@@ -53,12 +53,19 @@ func (m *Message) BodyLines() []string {
 	}
 }
 
-// Channel represents a channel in the list response.
+// Channel is a channel as GET /api/v1/channels and
+// GET /api/v1/state describe it.
 type Channel struct {
-	Name      string `json:"name"`
-	Topic     string `json:"topic"`
-	Members   int    `json:"members"`
-	CreatedAt string `json:"createdAt"`
+	Name  string `json:"name"`
+	Topic string `json:"topic"`
+}
+
+// Member is one entry of the response from
+// GET /api/v1/channels/{name}/members.
+type Member struct {
+	Nick       string `json:"nick"`
+	IsOperator bool   `json:"isOperator"`
+	IsVoiced   bool   `json:"isVoiced"`
 }
 
 // ServerInfo is the response from GET /api/v1/server.
@@ -72,7 +79,7 @@ type ServerInfo struct {
 // MessagesResponse wraps polling results.
 type MessagesResponse struct {
 	Messages []Message `json:"messages"`
-	LastID   int64     `json:"lastId"`
+	LastID   int64     `json:"last_id"` //nolint:tagliatelle
 }
 
 // PollResult wraps the poll response including the cursor.

internal/cli/app.go

@@ -96,20 +96,7 @@ func (a *App) handleInput(text string) {
 		a.ui.AddStatus(
 			"[red]Send error: " + err.Error(),
 		)
-
-		return
 	}
-
-	timestamp := time.Now().Format(timeFormat)
-
-	a.mu.Lock()
-	nick := a.nick
-	a.mu.Unlock()
-
-	a.ui.AddLine(target, fmt.Sprintf(
-		"[gray]%s [green]<%s>[white] %s",
-		timestamp, nick, text,
-	))
 }
 
 func (a *App) handleCommand(text string) {
@@ -301,9 +288,6 @@ func (a *App) cmdJoin(channel string) {
 	a.mu.Unlock()
 
 	a.ui.SwitchToBuffer(channel)
-	a.ui.AddLine(channel,
-		"[yellow]*** Joined "+channel,
-	)
 	a.ui.SetStatus(nick, channel, "connected")
 }
 
@@ -338,10 +322,6 @@ func (a *App) cmdPart(channel string) {
 		return
 	}
 
-	a.ui.AddLine(channel,
-		"[yellow]*** Left "+channel,
-	)
-
 	a.mu.Lock()
 	if a.target == channel {
 		a.target = ""
@@ -368,7 +348,6 @@ func (a *App) cmdMsg(args string) {
 
 	a.mu.Lock()
 	connected := a.connected
-	nick := a.nick
 	a.mu.Unlock()
 
 	if !connected {
@@ -386,16 +365,7 @@ func (a *App) cmdMsg(args string) {
 		a.ui.AddStatus(fmt.Sprintf(
 			"[red]Send failed: %v", err,
 		))
-
-		return
 	}
-
-	timestamp := time.Now().Format(timeFormat)
-
-	a.ui.AddLine(target, fmt.Sprintf(
-		"[gray]%s [green]<%s>[white] %s",
-		timestamp, nick, text,
-	))
 }
 
 func (a *App) cmdQuery(nick string) {
@@ -434,16 +404,9 @@ func (a *App) cmdTopic(args string) {
 		return
 	}
 
+	// The HTTP API has no topic query: a TOPIC needs text.
 	if args == "" {
-		err := a.client.SendMessage(&api.Message{ //nolint:exhaustruct
-			Command: irc.CmdTopic,
-			To:      target,
-		})
-		if err != nil {
-			a.ui.AddStatus(fmt.Sprintf(
-				"[red]Topic query failed: %v", err,
-			))
-		}
+		a.ui.AddStatus("[red]Usage: /topic <text>")
 
 		return
 	}
@@ -487,12 +450,32 @@ func (a *App) cmdNames() {
 		return
 	}
 
+	nicks := make([]string, 0, len(members))
+
+	for _, member := range members {
+		nicks = append(nicks, memberPrefix(member)+member.Nick)
+	}
+
 	a.ui.AddLine(target, fmt.Sprintf(
 		"[cyan]*** Members of %s: %s",
-		target, strings.Join(members, " "),
+		target, strings.Join(nicks, " "),
 	))
 }
 
+// memberPrefix returns "@" for an operator, "+" for a voiced
+// member, and "" for anyone else.
+func memberPrefix(member api.Member) string {
+	if member.IsOperator {
+		return "@"
+	}
+
+	if member.IsVoiced {
+		return "+"
+	}
+
+	return ""
+}
+
 func (a *App) cmdList() {
 	a.mu.Lock()
 	connected := a.connected
@@ -517,8 +500,7 @@ func (a *App) cmdList() {
 
 	for _, ch := range channels {
 		a.ui.AddStatus(fmt.Sprintf(
-			"  %s (%d members) %s",
-			ch.Name, ch.Members, ch.Topic,
+			"  %s %s", ch.Name, ch.Topic,
 		))
 	}
 
@@ -676,7 +658,7 @@ func (a *App) cmdHelp() {
 		"  /part [#chan]    — Leave channel",
 		"  /msg <nick> <text> — Send DM",
 		"  /query <nick>   — Open DM window",
-		"  /topic [text]   — View/set topic",
+		"  /topic <text>   — Set topic",
 		"  /names          — List channel members",
 		"  /list           — List channels",
 		"  /who [#channel] — List users in channel",
@@ -745,7 +727,7 @@ 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:
@@ -773,12 +755,10 @@ func (a *App) handlePrivmsgEvent(
 	lines := msg.BodyLines()
 	text := strings.Join(lines, " ")
 
-	if msg.From == myNick {
-		return
-	}
-
+	// A direct message shows in the buffer of the other user:
+	// the recipient of one the user sent, else the sender.
 	target := msg.To
-	if !strings.HasPrefix(target, "#") {
+	if !strings.HasPrefix(target, "#") && msg.From != myNick {
 		target = msg.From
 	}
 
@@ -801,8 +781,11 @@ func (a *App) handleJoinEvent(
 	))
 }
 
+// handlePartEvent shows a part in the channel's buffer. The
+// user's own part does not mark the channel unread: the user
+// has just left it.
 func (a *App) handlePartEvent(
-	msg *api.Message, timestamp string,
+	msg *api.Message, timestamp, myNick string,
 ) {
 	if msg.To == "" {
 		return
@@ -811,17 +794,22 @@ func (a *App) handlePartEvent(
 	lines := msg.BodyLines()
 	reason := strings.Join(lines, " ")
 
+	line := fmt.Sprintf(
+		"[gray]%s [yellow]*** %s has left %s",
+		timestamp, msg.From, msg.To,
+	)
+
 	if reason != "" {
-		a.ui.AddLine(msg.To, fmt.Sprintf(
-			"[gray]%s [yellow]*** %s has left %s (%s)",
-			timestamp, msg.From, msg.To, reason,
-		))
-	} else {
-		a.ui.AddLine(msg.To, fmt.Sprintf(
-			"[gray]%s [yellow]*** %s has left %s",
-			timestamp, msg.From, msg.To,
-		))
+		line += " (" + reason + ")"
 	}
+
+	if msg.From == myNick {
+		a.ui.AddLineAsRead(msg.To, line)
+
+		return
+	}
+
+	a.ui.AddLine(msg.To, line)
 }
 
 func (a *App) handleQuitEvent(

internal/cli/app_internal_test.go

@@ -0,0 +1,269 @@
+package cli
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gdamore/tcell/v2"
+	api "sneak.berlin/go/neoirc/internal/cli/api"
+	"sneak.berlin/go/neoirc/pkg/irc"
+)
+
+// The user's nick, a channel it is in, another user's nick and
+// a message text, for the tests below.
+const (
+	testNick      = "erin"
+	testChannel   = "#chan"
+	testOtherNick = "bob"
+	testText      = "hello"
+)
+
+func TestMemberPrefix(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name   string
+		member api.Member
+		want   string
+	}{
+		{
+			name:   "operator",
+			member: api.Member{Nick: "alice", IsOperator: true},
+			want:   "@",
+		},
+		{
+			name:   "voiced member",
+			member: api.Member{Nick: "bob", IsVoiced: true},
+			want:   "+",
+		},
+		{
+			name: "voiced operator",
+			member: api.Member{
+				Nick: "Carol", IsOperator: true, IsVoiced: true,
+			},
+			want: "@",
+		},
+		{
+			name:   "plain member",
+			member: api.Member{Nick: "dave"},
+			want:   "",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := memberPrefix(test.member)
+			if got != test.want {
+				t.Fatalf("got %q, want %q", got, test.want)
+			}
+		})
+	}
+}
+
+// TestPartEvent checks that a PART event adds a line to the
+// channel's buffer and marks it unread, except that the
+// user's own part does not mark it unread.
+func TestPartEvent(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		from       string
+		wantUnread int
+	}{
+		{name: "own part", from: testNick, wantUnread: 0},
+		{name: "other member", from: testOtherNick, wantUnread: 1},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			app := &App{ui: NewUI(), nick: testNick}
+			runUI(t, app.ui)
+
+			app.handleServerMessage(&api.Message{
+				Command: irc.CmdPart, From: test.from, To: testChannel,
+			})
+
+			lines, unread := bufferState(app.ui, testChannel)
+			if lines != 1 || unread != test.wantUnread {
+				t.Fatalf("got %d lines and %d unread, want 1 and %d",
+					lines, unread, test.wantUnread)
+			}
+		})
+	}
+}
+
+// TestOwnCommandShownOnce checks that a message, join or
+// part made from neoirc-cli shows as one line in the
+// channel's buffer once the server's event for it arrives,
+// and does not mark the channel unread.
+func TestOwnCommandShownOnce(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		send  func(app *App)
+		event api.Message
+	}{
+		{
+			name: "message",
+			send: func(app *App) { app.handleInput(testText) },
+			event: api.Message{
+				Command: irc.CmdPrivmsg, From: testNick, To: testChannel,
+				Body: []string{testText},
+			},
+		},
+		{
+			name: "join",
+			send: func(app *App) { app.cmdJoin(testChannel) },
+			event: api.Message{
+				Command: irc.CmdJoin, From: testNick, To: testChannel,
+			},
+		},
+		{
+			name: "part",
+			send: func(app *App) { app.cmdPart(testChannel) },
+			event: api.Message{
+				Command: irc.CmdPart, From: testNick, To: testChannel,
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			// The server accepts every command and answers nothing.
+			server := httptest.NewServer(http.HandlerFunc(
+				func(http.ResponseWriter, *http.Request) {},
+			))
+			t.Cleanup(server.Close)
+
+			app := &App{
+				ui:        NewUI(),
+				client:    api.NewClient(server.URL),
+				nick:      testNick,
+				target:    testChannel,
+				connected: true,
+			}
+			runUI(t, app.ui)
+			app.ui.SwitchToBuffer(testChannel)
+
+			test.send(app)
+			app.handleServerMessage(&test.event)
+
+			lines, unread := bufferState(app.ui, testChannel)
+			if lines != 1 || unread != 0 {
+				t.Fatalf("got %d lines and %d unread, want 1 and 0",
+					lines, unread)
+			}
+		})
+	}
+}
+
+// TestOwnEventFromOtherClient checks that a message, notice,
+// join or part that the user's session makes from another
+// client shows as one line in the buffer it belongs to.
+func TestOwnEventFromOtherClient(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name   string
+		event  api.Message
+		buffer string
+	}{
+		{
+			name: "channel message",
+			event: api.Message{
+				Command: irc.CmdPrivmsg, From: testNick, To: testChannel,
+				Body: []string{testText},
+			},
+			buffer: testChannel,
+		},
+		{
+			name: "direct message",
+			event: api.Message{
+				Command: irc.CmdPrivmsg, From: testNick, To: testOtherNick,
+				Body: []string{testText},
+			},
+			buffer: testOtherNick,
+		},
+		{
+			name: "notice",
+			event: api.Message{
+				Command: irc.CmdNotice, From: testNick, To: testChannel,
+				Body: []string{testText},
+			},
+			buffer: "(status)",
+		},
+		{
+			name: "join",
+			event: api.Message{
+				Command: irc.CmdJoin, From: testNick, To: testChannel,
+			},
+			buffer: testChannel,
+		},
+		{
+			name: "part",
+			event: api.Message{
+				Command: irc.CmdPart, From: testNick, To: testChannel,
+			},
+			buffer: testChannel,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			app := &App{ui: NewUI(), nick: testNick}
+			runUI(t, app.ui)
+
+			app.handleServerMessage(&test.event)
+
+			lines, _ := bufferState(app.ui, test.buffer)
+			if lines != 1 {
+				t.Fatalf("got %d lines in %s, want 1", lines, test.buffer)
+			}
+		})
+	}
+}
+
+// bufferState returns the number of lines in the named
+// buffer and how many of them are unread.
+func bufferState(ui *UI, name string) (int, int) {
+	var lines, unread int
+
+	ui.app.QueueUpdate(func() {
+		buf := ui.getOrCreateBuffer(name)
+		lines = len(buf.Lines)
+		unread = buf.Unread
+	})
+
+	return lines, unread
+}
+
+// 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/cli/ui.go

@@ -95,6 +95,19 @@ func (ui *UI) AddLine(bufferName, line string) {
 	})
 }
 
+// AddLineAsRead adds a line to the specified buffer, as
+// AddLine does, but does not mark the buffer unread.
+func (ui *UI) AddLineAsRead(bufferName, line string) {
+	ui.app.QueueUpdateDraw(func() {
+		buf := ui.getOrCreateBuffer(bufferName)
+		buf.Lines = append(buf.Lines, line)
+
+		if ui.buffers[ui.currentBuffer] == buf {
+			_, _ = fmt.Fprintln(ui.messages, line)
+		}
+	})
+}
+
 // AddStatus adds a line to the status buffer.
 func (ui *UI) AddStatus(line string) {
 	ts := time.Now().Format("15:04")

internal/db/queries.go

@@ -264,6 +264,25 @@ func (database *Database) GetSessionByNick(
 	return sessionID, nil
 }
 
+// GetSessionNick returns the nick a session holds.
+func (database *Database) GetSessionNick(
+	ctx context.Context,
+	sessionID int64,
+) (string, error) {
+	var nick string
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		"SELECT nick FROM sessions WHERE id = ?",
+		sessionID,
+	).Scan(&nick)
+	if err != nil {
+		return "", fmt.Errorf("get session nick: %w", err)
+	}
+
+	return nick, nil
+}
+
 // SessionHostInfo holds the username, hostname, and IP
 // for a session.
 type SessionHostInfo struct {
@@ -1208,11 +1227,12 @@ func insertMessageInTx(
 	return dbID, msgUUID, nil
 }
 
-// EnqueueToSession adds a message to all clients of a
-// session's queues.
+// EnqueueToSession adds a message to the queues of all
+// 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 +1241,9 @@ 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 +1261,15 @@ 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 = ?`,
-		messageID, time.Now(), sessionID)
+		 WHERE c.session_id = ? AND c.id != ?`,
+		messageID, time.Now(), sessionID, skipClientID)
 	if err != nil {
 		return fmt.Errorf(
 			"enqueue to session: %w", err,
@@ -1673,7 +1695,7 @@ 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

@@ -199,7 +199,7 @@ func (hdlr *Handlers) handleCreateSession(
 		return
 	}
 
-	if !hdlr.validateHashcash(
+	if !hdlr.checkHashcash(
 		writer, request, payload.Hashcash,
 	) {
 		return
@@ -232,14 +232,15 @@ func (hdlr *Handlers) handleCreateSession(
 	}
 
 	hdlr.executeCreateSession(
-		writer, request, payload.Nick, username,
+		writer, request,
+		payload.Nick, username, payload.Hashcash,
 	)
 }
 
 func (hdlr *Handlers) executeCreateSession(
 	writer http.ResponseWriter,
 	request *http.Request,
-	nick, username string,
+	nick, username, stamp string,
 ) {
 	remoteIP := clientIP(request)
 
@@ -247,12 +248,17 @@ func (hdlr *Handlers) executeCreateSession(
 		request.Context(), remoteIP,
 	)
 
+	if !hdlr.claimHashcash(writer, request, stamp) {
+		return
+	}
+
 	sessionID, clientID, token, err :=
 		hdlr.params.Database.CreateSession(
 			request.Context(),
 			nick, username, hostname, remoteIP,
 		)
 	if err != nil {
+		hdlr.hashcashVal.Release(stamp)
 		hdlr.handleCreateSessionError(
 			writer, request, err,
 		)
@@ -273,10 +279,10 @@ func (hdlr *Handlers) executeCreateSession(
 	}, http.StatusCreated)
 }
 
-// validateHashcash validates a hashcash stamp if required.
-// Returns false if validation failed and a response was
-// already sent.
-func (hdlr *Handlers) validateHashcash(
+// checkHashcash checks a hashcash stamp if required,
+// without spending it. Returns false if the check failed
+// and a response was already sent.
+func (hdlr *Handlers) checkHashcash(
 	writer http.ResponseWriter,
 	request *http.Request,
 	stamp string,
@@ -295,7 +301,31 @@ func (hdlr *Handlers) validateHashcash(
 		return false
 	}
 
-	err := hdlr.hashcashVal.Validate(
+	err := hdlr.hashcashVal.Check(
+		stamp, hdlr.params.Config.HashcashBits,
+	)
+	if err != nil {
+		hdlr.respondError(
+			writer, request,
+			"invalid hashcash stamp: "+err.Error(),
+			http.StatusPaymentRequired,
+		)
+
+		return false
+	}
+
+	return true
+}
+
+// claimHashcash spends a stamp that checkHashcash accepted.
+// Returns false if Claim refused the stamp, normally because
+// it was already spent, and a response was already sent.
+func (hdlr *Handlers) claimHashcash(
+	writer http.ResponseWriter,
+	request *http.Request,
+	stamp string,
+) bool {
+	err := hdlr.hashcashVal.Claim(
 		stamp, hdlr.params.Config.HashcashBits,
 	)
 	if err != nil {
@@ -783,7 +813,14 @@ func (hdlr *Handlers) HandleGetMessages() http.HandlerFunc {
 			timeout = maxLongPollTimeout
 		}
 
-		msgs, lastQID, err := hdlr.params.Database.PollMessages(
+		// Register with the broker before reading the queue.
+		// Notify wakes only the channels registered at that
+		// moment, so a message queued after the read below
+		// must find this one there already.
+		waitCh := hdlr.broker.Wait(sessionID)
+		defer hdlr.broker.Remove(sessionID, waitCh)
+
+		msgs, lastQID, err := hdlr.pollMessages(
 			request.Context(), clientID,
 			afterID, pollMessageLimit,
 		)
@@ -811,19 +848,22 @@ func (hdlr *Handlers) HandleGetMessages() http.HandlerFunc {
 
 		hdlr.longPoll(
 			writer, request,
-			sessionID, clientID, afterID, timeout,
+			waitCh, clientID, afterID, timeout,
 		)
 	}
 }
 
+// longPoll waits up to timeout seconds for the broker to
+// signal waitCh, then answers with the messages queued for
+// clientID after afterID. It answers nothing if the client
+// goes away first.
 func (hdlr *Handlers) longPoll(
 	writer http.ResponseWriter,
 	request *http.Request,
-	sessionID, clientID, afterID int64,
+	waitCh <-chan struct{},
+	clientID, afterID int64,
 	timeout int,
 ) {
-	waitCh := hdlr.broker.Wait(sessionID)
-
 	timer := time.NewTimer(
 		time.Duration(timeout) * time.Second,
 	)
@@ -834,14 +874,10 @@ func (hdlr *Handlers) longPoll(
 	case <-waitCh:
 	case <-timer.C:
 	case <-request.Context().Done():
-		hdlr.broker.Remove(sessionID, waitCh)
-
 		return
 	}
 
-	hdlr.broker.Remove(sessionID, waitCh)
-
-	msgs, lastQID, err := hdlr.params.Database.PollMessages(
+	msgs, lastQID, err := hdlr.pollMessages(
 		request.Context(), clientID,
 		afterID, pollMessageLimit,
 	)
@@ -1221,9 +1257,11 @@ func (hdlr *Handlers) handleChannelMsg(
 ) {
 	ctx := request.Context()
 
-	// Delegate validation + fan-out to service layer.
-	dbID, uuid, err := hdlr.svc.SendChannelMessage(
-		ctx, sessionID, nick,
+	// Delegate validation + fan-out to service layer. The
+	// fan-out includes the sender's own session, so all
+	// 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(
@@ -1233,13 +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)
@@ -1254,7 +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(
@@ -1325,7 +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(
@@ -1509,7 +1540,7 @@ func (hdlr *Handlers) handlePart(
 	}
 
 	err := hdlr.svc.PartChannel(
-		request.Context(), sessionID,
+		request.Context(), sessionID, 0,
 		nick, channel, reason,
 	)
 	if hdlr.handleServiceError(
@@ -1580,7 +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,
@@ -1635,7 +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(
@@ -2121,7 +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,
 	)
 
@@ -2167,7 +2198,7 @@ func (hdlr *Handlers) setChannelFlag(
 	}
 
 	hdlr.svc.BroadcastMode(
-		request.Context(), nick, channel, chID,
+		request.Context(), 0, nick, channel, chID,
 		modeStr,
 	)
 
@@ -3614,7 +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(
@@ -3687,7 +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

@@ -29,6 +29,7 @@ import (
 	"golang.org/x/crypto/bcrypt"
 	"modernc.org/sqlite"
 	"sneak.berlin/go/neoirc/internal/broker"
+	api "sneak.berlin/go/neoirc/internal/cli/api"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
 	"sneak.berlin/go/neoirc/internal/globals"
@@ -126,6 +127,7 @@ const (
 	privmsgCmd     = "PRIVMSG"
 	joinCmd        = "JOIN"
 	apiMessages    = "/api/v1/messages"
+	apiLogout      = "/api/v1/logout"
 	apiSession     = "/api/v1/session"
 	apiState       = "/api/v1/state"
 	authCookieName = "neoirc_auth"
@@ -136,6 +138,9 @@ type testServer struct {
 	httpServer *httptest.Server
 	t          *testing.T
 	fxApp      *fxtest.App
+	broker     *broker.Broker
+	database   *db.Database
+	handlers   *handlers.Handlers
 }
 
 func newTestServer(
@@ -162,7 +167,12 @@ func newTestServerWith(
 	)
 	copyTemplateDB(t, dbURL)
 
-	var srv *server.Server
+	var (
+		srv      *server.Server
+		brk      *broker.Broker
+		database *db.Database
+		hdlr     *handlers.Handlers
+	)
 
 	app := fxtest.New(t,
 		fx.Provide(
@@ -195,13 +205,14 @@ func newTestServerWith(
 				return cfg, nil
 			},
 			newTestDB,
+			broker.New,
 			stats.New,
 			newTestHealthcheck,
 			newTestMiddleware,
 			newTestHandlers,
 			newTestServerFx,
 		),
-		fx.Populate(&srv),
+		fx.Populate(&srv, &brk, &database, &hdlr),
 	)
 
 	app.RequireStart()
@@ -217,6 +228,9 @@ func newTestServerWith(
 		httpServer: httpSrv,
 		t:          t,
 		fxApp:      app,
+		broker:     brk,
+		database:   database,
+		handlers:   hdlr,
 	}
 }
 
@@ -291,8 +305,8 @@ func newTestHandlers(
 	database *db.Database,
 	hcheck *healthcheck.Healthcheck,
 	tracker *stats.Tracker,
+	brk *broker.Broker,
 ) (*handlers.Handlers, error) {
-	brk := broker.New()
 	svc := service.New(service.Params{ //nolint:exhaustruct
 		Logger:   log,
 		Config:   cfg,
@@ -325,6 +339,7 @@ func newTestServerFx(
 	cfg *config.Config,
 	mware *middleware.Middleware,
 	hdlr *handlers.Handlers,
+	shutdowner fx.Shutdowner,
 ) (*server.Server, error) {
 	srv, err := server.New(lifecycle, server.Params{ //nolint:exhaustruct
 		Logger:     log,
@@ -332,6 +347,7 @@ func newTestServerFx(
 		Config:     cfg,
 		Middleware: mware,
 		Handlers:   hdlr,
+		Shutdowner: shutdowner,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("test server: %w", err)
@@ -1402,7 +1418,7 @@ const quitRaceTrials = 5
 // is sent once.
 func TestConcurrentLogoutsSendOneQuit(t *testing.T) {
 	checkQuitRace(t, func(tserver *testServer, tokens []string) {
-		tserver.postConcurrently("/api/v1/logout", nil, tokens...)
+		tserver.postConcurrently(apiLogout, nil, tokens...)
 	})
 }
 
@@ -1517,15 +1533,7 @@ func TestLogoutOfOneClientKeepsSession(t *testing.T) {
 		t.Fatalf("other client's state: got %d, want 200", status)
 	}
 
-	channels, _ := state["channels"].([]any)
-	names := make([]string, 0, len(channels))
-
-	for _, entry := range channels {
-		info, _ := entry.(map[string]any)
-		name, _ := info["name"].(string)
-		names = append(names, name)
-	}
-
+	names := channelNames(state)
 	if !slices.Equal(names, []string{channel}) {
 		t.Errorf("session's channels: got %v, want [%s]", names, channel)
 	}
@@ -1547,6 +1555,201 @@ func TestLogoutOfOneClientKeepsSession(t *testing.T) {
 	}
 }
 
+// TestFailedLogoutChangesNothing checks that a logout whose
+// session cannot be deleted answers 500 and changes
+// nothing: the client's token still works, the session is
+// still on its channel and its channel peer has no QUIT.
+func TestFailedLogoutChangesNothing(t *testing.T) {
+	const (
+		nick    = "stuckleaver"
+		channel = "#stuck"
+	)
+
+	tserver := newTestServer(t)
+	token := tserver.createSession(nick)
+	observerToken := tserver.createSession("stuckobserver")
+
+	for _, joiner := range []string{token, observerToken} {
+		tserver.sendCommand(joiner, map[string]any{
+			commandKey: joinCmd, toKey: channel,
+		})
+	}
+
+	_, lastID := tserver.pollMessages(observerToken, 0)
+
+	_, err := tserver.database.GetDB().ExecContext(t.Context(),
+		`CREATE TRIGGER keep_sessions
+		 BEFORE DELETE ON sessions
+		 BEGIN
+		   SELECT RAISE(ABORT, 'sessions are kept');
+		 END`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	resp, err := doRequestAuth(
+		t, http.MethodPost, tserver.url(apiLogout), token, nil,
+	)
+	if err != nil {
+		t.Fatalf("logout: %v", err)
+	}
+
+	_ = resp.Body.Close()
+
+	if resp.StatusCode != http.StatusInternalServerError {
+		t.Errorf("logout: got %d, want 500", resp.StatusCode)
+	}
+
+	status, state := tserver.getState(token)
+	if status != http.StatusOK {
+		t.Fatalf("state after the failed logout: got %d, want 200", status)
+	}
+
+	names := channelNames(state)
+	if !slices.Equal(names, []string{channel}) {
+		t.Errorf("session's channels: got %v, want [%s]", names, channel)
+	}
+
+	msgs, _ := tserver.pollMessages(observerToken, lastID)
+
+	quits := countQuits(msgs, nick)
+	if quits != 0 {
+		t.Errorf("%d QUITs, want 0: %v", quits, msgs)
+	}
+}
+
+const (
+	// quitWakePollTimeout is the timeout, in seconds, of the
+	// long poll in checkQuitWakesPoll.
+	quitWakePollTimeout = 10
+
+	// quitWakeDeadline is how long checkQuitWakesPoll waits
+	// for that long poll to start waiting, and then to
+	// return once the session has left.
+	quitWakeDeadline = 5 * time.Second
+
+	// pollWaitStep is how often checkQuitWakesPoll checks
+	// whether the long poll is waiting yet.
+	pollWaitStep = 10 * time.Millisecond
+)
+
+// TestQuitWakesPeerLongPoll checks that a session's QUIT
+// wakes the long poll of a user who shares a channel with
+// it.
+func TestQuitWakesPeerLongPoll(t *testing.T) {
+	const reason = "gone fishing"
+
+	checkQuitWakesPoll(t, reason, func(tserver *testServer, token string) {
+		tserver.sendCommand(token, map[string]any{
+			commandKey: irc.CmdQuit, bodyKey: []string{reason},
+		})
+	})
+}
+
+// TestLastLogoutWakesPeerLongPoll checks that the logout of
+// a session's last client wakes the long poll of a user who
+// shares a channel with it.
+func TestLastLogoutWakesPeerLongPoll(t *testing.T) {
+	checkQuitWakesPoll(t, "Connection closed", func(tserver *testServer, token string) {
+		tserver.logout(token)
+	})
+}
+
+// checkQuitWakesPoll puts a session and a peer on a
+// channel, and calls leave with the session's token while
+// the peer long-polls with a timeout of quitWakePollTimeout
+// seconds. It checks that the poll returns within
+// quitWakeDeadline with the session's QUIT, whose body is
+// reason.
+func checkQuitWakesPoll(
+	t *testing.T,
+	reason string,
+	leave func(tserver *testServer, token string),
+) {
+	t.Helper()
+
+	const (
+		nick     = "wakequitter"
+		peerNick = "wakepeer"
+	)
+
+	tserver := newTestServer(t)
+	token := tserver.createSession(nick)
+	peerToken := tserver.createSession(peerNick)
+
+	for _, joiner := range []string{token, peerToken} {
+		tserver.sendCommand(joiner, map[string]any{
+			commandKey: joinCmd, toKey: "#wake",
+		})
+	}
+
+	_, lastID := tserver.pollMessages(peerToken, 0)
+
+	peerID, err := tserver.database.GetSessionByNick(t.Context(), peerNick)
+	if err != nil {
+		t.Fatalf("get session of %s: %v", peerNick, err)
+	}
+
+	var (
+		msgs    []map[string]any
+		pollErr error
+	)
+
+	polled := make(chan struct{})
+
+	go func() {
+		defer close(polled)
+
+		msgs, pollErr = tserver.longPoll(peerToken, lastID, quitWakePollTimeout)
+	}()
+
+	deadline := time.Now().Add(quitWakeDeadline)
+
+	for tserver.broker.ListenerCount(peerID) == 0 {
+		if time.Now().After(deadline) {
+			t.Fatal("the long poll did not start waiting")
+		}
+
+		time.Sleep(pollWaitStep)
+	}
+
+	leave(tserver, token)
+
+	select {
+	case <-polled:
+	case <-time.After(quitWakeDeadline):
+		t.Fatalf("the long poll did not return within %v", quitWakeDeadline)
+	}
+
+	if pollErr != nil {
+		t.Fatalf("long poll: %v", pollErr)
+	}
+
+	if len(msgs) != 1 || countQuits(msgs, nick) != 1 {
+		t.Fatalf("long poll: got %v, want one QUIT from %s", msgs, nick)
+	}
+
+	lines, _ := msgs[0][bodyKey].([]any)
+	if len(lines) != 1 || lines[0] != reason {
+		t.Errorf("QUIT body: got %v, want [%s]", lines, reason)
+	}
+}
+
+// channelNames returns the names of the channels in state,
+// a response to GET /api/v1/state.
+func channelNames(state map[string]any) []string {
+	channels, _ := state["channels"].([]any)
+	names := make([]string, 0, len(channels))
+
+	for _, entry := range channels {
+		info, _ := entry.(map[string]any)
+		name, _ := info["name"].(string)
+		names = append(names, name)
+	}
+
+	return names
+}
+
 // countQuits returns how many of msgs are a QUIT from nick.
 func countQuits(msgs []map[string]any, nick string) int {
 	quits := 0
@@ -1567,7 +1770,7 @@ func (tserver *testServer) logout(token string) {
 
 	resp, err := doRequestAuth(
 		tserver.t, http.MethodPost,
-		tserver.url("/api/v1/logout"), token, nil,
+		tserver.url(apiLogout), token, nil,
 	)
 	if err != nil {
 		tserver.t.Fatalf("logout: %v", err)
@@ -1580,6 +1783,38 @@ func (tserver *testServer) logout(token string) {
 	}
 }
 
+// longPoll returns the messages after afterID that the
+// client token has been sent, waiting up to timeout seconds
+// for one if there are none yet. It returns errors instead
+// of failing the test, so a goroutine can call it.
+func (tserver *testServer) longPoll(
+	token string, afterID int64, timeout int,
+) ([]map[string]any, error) {
+	resp, err := doRequestAuth(
+		tserver.t, http.MethodGet,
+		tserver.url(fmt.Sprintf(
+			"%s?timeout=%d&after=%d", apiMessages, timeout, afterID,
+		)),
+		token, nil,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	var result struct {
+		Messages []map[string]any `json:"messages"`
+	}
+
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	if err != nil {
+		return nil, fmt.Errorf("decode poll: %w", err)
+	}
+
+	return result.Messages, nil
+}
+
 // login logs in to the session nick with testPassword and
 // returns the new client's token.
 func (tserver *testServer) login(nick string) string {
@@ -2322,6 +2557,364 @@ func TestLongPollTimeout(t *testing.T) {
 	}
 }
 
+// TestLongPollReturnsMessageQueuedAfterFirstRead checks that
+// a message queued, and the broker notified, after the long
+// poll's first read of the queue found nothing but before the
+// poll waits, is returned at once and not when the poll times
+// out, and that the poll then holds no broker wait channel.
+func TestLongPollReturnsMessageQueuedAfterFirstRead(t *testing.T) {
+	const (
+		nick   = "lp_late"
+		sender = "lp_late_sender"
+
+		// pollTimeout is the long poll's timeout, in seconds.
+		pollTimeout = 10
+
+		// atOnce is the longest the long poll may take to
+		// return the message.
+		atOnce = 5 * time.Second
+	)
+
+	tserver := newTestServer(t)
+	token := tserver.createSession(nick)
+
+	_, lastID := tserver.pollMessages(token, 0)
+
+	sessionID, err := tserver.database.GetSessionByNick(t.Context(), nick)
+	if err != nil {
+		t.Fatalf("get session of %s: %v", nick, err)
+	}
+
+	queued := make(chan error, 1)
+
+	var once sync.Once
+
+	tserver.handlers.SetPollMessages(func(
+		ctx context.Context,
+		clientID, afterQueueID int64,
+		limit int,
+	) ([]db.IRCMessage, int64, error) {
+		msgs, lastQID, pollErr := tserver.database.PollMessages(
+			ctx, clientID, afterQueueID, limit,
+		)
+
+		once.Do(func() {
+			queued <- tserver.queueMessage(ctx, sessionID, sender, nick)
+		})
+
+		return msgs, lastQID, pollErr
+	})
+
+	start := time.Now()
+
+	msgs, err := tserver.longPoll(token, lastID, pollTimeout)
+	if err != nil {
+		t.Fatalf("long poll: %v", err)
+	}
+
+	elapsed := time.Since(start)
+
+	select {
+	case queueErr := <-queued:
+		if queueErr != nil {
+			t.Fatalf("queue message: %v", queueErr)
+		}
+	default:
+		t.Fatal("the long poll did not read the queue")
+	}
+
+	if elapsed > atOnce {
+		t.Fatalf("the long poll returned after %v, want within %v",
+			elapsed, atOnce)
+	}
+
+	if !findMessage(msgs, privmsgCmd, sender) {
+		t.Fatalf("long poll: got %v, want the PRIVMSG from %s",
+			msgs, sender)
+	}
+
+	tserver.checkWaitChannelRemoved(sessionID)
+}
+
+// errReadFailed is what a test's replacement for
+// Database.PollMessages returns to make a read of the queue
+// fail.
+var errReadFailed = errors.New("read failed")
+
+// TestGetMessagesRemovesWaitChannel checks that a request to
+// GET /api/v1/messages leaves no broker wait channel behind,
+// whether it is answered at once, after its timeout, or with
+// an error because a read of the queue failed.
+func TestGetMessagesRemovesWaitChannel(t *testing.T) {
+	const (
+		// longTimeout, in seconds, is the timeout of the
+		// requests that must be answered without waiting.
+		longTimeout = 10
+
+		// shortTimeout, in seconds, is the timeout of the
+		// requests that wait it out.
+		shortTimeout = 1
+	)
+
+	// queued is whether a message is queued before the request,
+	// whose timeout is in seconds. failingRead is as for
+	// getMessagesFailingRead. wantReads is how many times the
+	// handler reads the queue: once if it answers at once,
+	// twice if it waits first.
+	tests := []struct {
+		name                  string
+		queued                bool
+		timeout, failingRead  int
+		wantReads, wantStatus int
+	}{
+		{
+			name: "nothing queued, timeout 0", timeout: 0,
+			wantReads: 1, wantStatus: http.StatusOK,
+		},
+		{
+			name: "message queued", queued: true, timeout: longTimeout,
+			wantReads: 1, wantStatus: http.StatusOK,
+		},
+		{
+			name: "timed out", timeout: shortTimeout,
+			wantReads: 2, wantStatus: http.StatusOK,
+		},
+		{
+			name: "first read failed", timeout: longTimeout, failingRead: 1,
+			wantReads: 1, wantStatus: http.StatusInternalServerError,
+		},
+		{
+			name: "read after the wait failed", timeout: shortTimeout,
+			failingRead: 2, wantReads: 2,
+			wantStatus: http.StatusInternalServerError,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			const nick = "wc_poller"
+
+			tserver := newTestServer(t)
+			token := tserver.createSession(nick)
+
+			_, lastID := tserver.pollMessages(token, 0)
+
+			sessionID, err := tserver.database.GetSessionByNick(
+				t.Context(), nick,
+			)
+			if err != nil {
+				t.Fatalf("get session of %s: %v", nick, err)
+			}
+
+			if tc.queued {
+				err = tserver.queueMessage(
+					t.Context(), sessionID, "wc_sender", nick,
+				)
+				if err != nil {
+					t.Fatalf("queue message: %v", err)
+				}
+			}
+
+			status, reads := tserver.getMessagesFailingRead(
+				token, lastID, tc.timeout, tc.failingRead,
+			)
+			if status != tc.wantStatus {
+				t.Errorf("status %d, want %d", status, tc.wantStatus)
+			}
+
+			if reads != tc.wantReads {
+				t.Errorf("the handler read the queue %d times, want %d",
+					reads, tc.wantReads)
+			}
+
+			tserver.checkWaitChannelRemoved(sessionID)
+		})
+	}
+}
+
+// getMessagesFailingRead sends GET /api/v1/messages for the
+// client token with timeout and after afterID. The handler's
+// read of the queue numbered failingRead, counting from 1,
+// fails; with 0, none does. It returns the response status
+// and how many times the handler read the queue.
+func (tserver *testServer) getMessagesFailingRead(
+	token string,
+	afterID int64,
+	timeout, failingRead int,
+) (int, int) {
+	tserver.t.Helper()
+
+	reads := 0
+
+	tserver.handlers.SetPollMessages(func(
+		ctx context.Context,
+		clientID, afterQueueID int64,
+		limit int,
+	) ([]db.IRCMessage, int64, error) {
+		reads++
+
+		if reads == failingRead {
+			return nil, 0, errReadFailed
+		}
+
+		return tserver.database.PollMessages(
+			ctx, clientID, afterQueueID, limit,
+		)
+	})
+
+	resp, err := doRequestAuth(
+		tserver.t, http.MethodGet,
+		tserver.url(fmt.Sprintf(
+			"%s?timeout=%d&after=%d", apiMessages, timeout, afterID,
+		)),
+		token, nil,
+	)
+	if err != nil {
+		tserver.t.Fatalf("get messages: %v", err)
+	}
+
+	_ = resp.Body.Close()
+
+	return resp.StatusCode, reads
+}
+
+// TestLongPollRemovesWaitChannelWhenClientGivesUp checks that
+// a long poll whose client gives up while it waits leaves no
+// broker wait channel behind.
+func TestLongPollRemovesWaitChannelWhenClientGivesUp(t *testing.T) {
+	const (
+		nick = "wc_leaver"
+
+		// pollTimeout is the long poll's timeout, in seconds.
+		pollTimeout = 10
+
+		// readDeadline is how long the handler has to read
+		// the queue.
+		readDeadline = 5 * time.Second
+	)
+
+	tserver := newTestServer(t)
+	token := tserver.createSession(nick)
+
+	_, lastID := tserver.pollMessages(token, 0)
+
+	sessionID, err := tserver.database.GetSessionByNick(t.Context(), nick)
+	if err != nil {
+		t.Fatalf("get session of %s: %v", nick, err)
+	}
+
+	read := make(chan struct{})
+
+	var once sync.Once
+
+	tserver.handlers.SetPollMessages(func(
+		ctx context.Context,
+		clientID, afterQueueID int64,
+		limit int,
+	) ([]db.IRCMessage, int64, error) {
+		msgs, lastQID, pollErr := tserver.database.PollMessages(
+			ctx, clientID, afterQueueID, limit,
+		)
+
+		once.Do(func() { close(read) })
+
+		return msgs, lastQID, pollErr
+	})
+
+	ctx, giveUp := context.WithCancel(t.Context())
+	defer giveUp()
+
+	request, err := http.NewRequestWithContext(
+		ctx, http.MethodGet,
+		tserver.url(fmt.Sprintf(
+			"%s?timeout=%d&after=%d", apiMessages, pollTimeout, lastID,
+		)),
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("new request: %v", err)
+	}
+
+	request.AddCookie(&http.Cookie{ //nolint:exhaustruct,gosec // only name+value
+		Name:  authCookieName,
+		Value: token,
+	})
+
+	done := make(chan struct{})
+
+	go func() {
+		defer close(done)
+
+		resp, doErr := http.DefaultClient.Do(request)
+		if doErr == nil {
+			_ = resp.Body.Close()
+		}
+	}()
+
+	select {
+	case <-read:
+	case <-time.After(readDeadline):
+		t.Fatal("the long poll did not read the queue")
+	}
+
+	giveUp()
+	<-done
+
+	tserver.checkWaitChannelRemoved(sessionID)
+}
+
+// checkWaitChannelRemoved fails the test unless the broker
+// holds no wait channel for the session sessionID. A client
+// can have its response before the handler has returned, and
+// a handler notices a client that gives up only later, so it
+// waits up to removeDeadline for that.
+func (tserver *testServer) checkWaitChannelRemoved(sessionID int64) {
+	tserver.t.Helper()
+
+	const (
+		removeDeadline = 5 * time.Second
+		checkStep      = 10 * time.Millisecond
+	)
+
+	deadline := time.Now().Add(removeDeadline)
+
+	for tserver.broker.ListenerCount(sessionID) != 0 {
+		if time.Now().After(deadline) {
+			tserver.t.Fatalf("got %d broker wait channels, want 0",
+				tserver.broker.ListenerCount(sessionID))
+		}
+
+		time.Sleep(checkStep)
+	}
+}
+
+// queueMessage stores a PRIVMSG from sender to nick, queues
+// it to the session sessionID and notifies the broker, as the
+// server does for a DM. It returns errors instead of failing
+// the test, so a handler's goroutine can call it.
+func (tserver *testServer) queueMessage(
+	ctx context.Context,
+	sessionID int64,
+	sender, nick string,
+) error {
+	msgID, _, err := tserver.database.InsertMessage(
+		ctx, privmsgCmd, sender, nick, sessionID, 0,
+		nil, json.RawMessage(`["hello"]`), nil,
+	)
+	if err != nil {
+		return fmt.Errorf("insert message: %w", err)
+	}
+
+	err = tserver.database.EnqueueToSession(ctx, sessionID, msgID, 0)
+	if err != nil {
+		return fmt.Errorf("enqueue: %w", err)
+	}
+
+	tserver.broker.Notify(sessionID)
+
+	return nil
+}
+
 func TestEphemeralChannelCleanup(t *testing.T) {
 	const channel = "#ephemeral"
 
@@ -2674,32 +3267,73 @@ func TestPassCommand(t *testing.T) {
 	}
 }
 
-func TestPassCommandShortPassword(t *testing.T) {
-	tserver := newTestServer(t)
-	token := tserver.createSession("shortpw")
+// The shortest and longest password PASS accepts; bcrypt
+// cannot hash more than 72 bytes.
+const (
+	minPasswordBytes = 8
+	maxPasswordBytes = 72
+)
 
-	// Drain initial messages.
-	_, lastID := tserver.pollMessages(token, 0)
-
-	// Try short password — should fail.
-	status, _ := tserver.sendCommand(
-		token,
-		map[string]any{
-			commandKey: irc.CmdPass,
-			bodyKey:    []string{"short"},
-		},
-	)
-	if status != http.StatusOK {
-		t.Fatalf("expected 200, got %d", status)
+// TestPassCommandLength checks that PASS stores a password of
+// 8 to 72 bytes and refuses any other with 461. The limit
+// counts bytes: "é" is two bytes in UTF-8, so 72 of them are
+// refused.
+func TestPassCommandLength(t *testing.T) {
+	cases := []struct {
+		name     string
+		password string
+		stored   bool
+	}{
+		{"empty", "", false},
+		{"7 bytes", strings.Repeat("a", minPasswordBytes-1), false},
+		{"8 bytes", strings.Repeat("a", minPasswordBytes), true},
+		{"72 bytes", strings.Repeat("a", maxPasswordBytes), true},
+		{"73 bytes", strings.Repeat("a", maxPasswordBytes+1), false},
+		{"72 characters", strings.Repeat("é", maxPasswordBytes), false},
 	}
 
-	msgs, _ := tserver.pollMessages(token, lastID)
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			tserver := newTestServer(t)
+			token := tserver.createSession("pwlength")
 
-	if !findNumeric(msgs, "461") {
-		t.Fatalf(
-			"expected ERR_NEEDMOREPARAMS (461), got %v",
-			msgs,
-		)
+			_, lastID := tserver.pollMessages(token, 0)
+
+			status, result := tserver.sendCommand(
+				token,
+				map[string]any{
+					commandKey: irc.CmdPass,
+					bodyKey:    []string{tc.password},
+				},
+			)
+			if status != http.StatusOK {
+				t.Fatalf("expected 200, got %d: %v", status, result)
+			}
+
+			if !tc.stored {
+				msgs, _ := tserver.pollMessages(token, lastID)
+				if !findNumeric(msgs, "461") {
+					t.Fatalf(
+						"expected ERR_NEEDMOREPARAMS (461), got %v",
+						msgs,
+					)
+				}
+
+				return
+			}
+
+			if result[statusKey] != "ok" {
+				t.Fatalf("expected ok, got %v", result)
+			}
+
+			postJSONExpectStatus(
+				t, tserver, "/api/v1/login",
+				map[string]string{
+					nickKey: "pwlength", passwordKey: tc.password,
+				},
+				http.StatusOK,
+			)
+		})
 	}
 }
 
@@ -3842,6 +4476,121 @@ func TestChannelHashcashMissingBitsArg(t *testing.T) {
 	}
 }
 
+// postSessionWithStamp posts a session request for nick and
+// username carrying stamp and returns the response status.
+// An empty username defaults to the nick.
+func postSessionWithStamp(
+	t *testing.T,
+	tserver *testServer,
+	nick, username, stamp string,
+) int {
+	t.Helper()
+
+	body, err := json.Marshal(map[string]string{
+		nickKey: nick, "username": username, "pow_token": stamp,
+	})
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+
+	resp, err := doRequest(
+		t, http.MethodPost, tserver.url(apiSession),
+		bytes.NewReader(body),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_ = resp.Body.Close()
+
+	return resp.StatusCode
+}
+
+// sessionCount returns the number of sessions in tserver's
+// database.
+func sessionCount(t *testing.T, tserver *testServer) int64 {
+	t.Helper()
+
+	count, err := tserver.database.GetUserCount(t.Context())
+	if err != nil {
+		t.Fatalf("count sessions: %v", err)
+	}
+
+	return count
+}
+
+// TestRefusedSessionLeavesStampUnspent checks that a
+// session request is refused with 402 for an invalid stamp
+// before its nick is looked at, that a request refused with
+// 400 or 409 does not spend its stamp, so the same stamp
+// then creates a session, that the stamp stays spent after
+// that, that a spent stamp with an invalid nick is refused
+// for its nick, and that no refused request creates a
+// session.
+func TestRefusedSessionLeavesStampUnspent(t *testing.T) {
+	const (
+		bits    = 2
+		badNick = "bad nick"
+	)
+
+	tserver := newTestServerWith(t, bits, "", "")
+
+	// A server with no SERVER_NAME takes stamps for "neoirc".
+	status := postSessionWithStamp(
+		t, tserver, "taken", "", api.MintHashcash(bits, "neoirc"),
+	)
+	if status != http.StatusCreated {
+		t.Fatalf("create taken: want 201, got %d", status)
+	}
+
+	stamp := api.MintHashcash(bits, "neoirc")
+	otherServerStamp := api.MintHashcash(bits, "elsewhere")
+
+	steps := []struct {
+		nick, username, stamp string
+		want                  int
+	}{
+		{badNick, "", otherServerStamp, http.StatusPaymentRequired},
+		{badNick, "", stamp, http.StatusBadRequest},
+		{"fresh", "bad username", stamp, http.StatusBadRequest},
+		{"taken", "", stamp, http.StatusConflict},
+		{"fresh", "", stamp, http.StatusCreated},
+		{"another", "", stamp, http.StatusPaymentRequired},
+		// Refused as already spent, the stamp is not given back.
+		{"later", "", stamp, http.StatusPaymentRequired},
+		// Whether the stamp is spent is looked at after the nick.
+		{badNick, "", stamp, http.StatusBadRequest},
+		// The refused request for "another" left the nick free.
+		{"another", "", api.MintHashcash(bits, "neoirc"), http.StatusCreated},
+	}
+
+	sessions := sessionCount(t, tserver)
+
+	for _, step := range steps {
+		status = postSessionWithStamp(
+			t, tserver, step.nick, step.username, step.stamp,
+		)
+		if status != step.want {
+			t.Fatalf(
+				"nick %q, username %q: want %d, got %d",
+				step.nick, step.username, step.want, status,
+			)
+		}
+
+		if status == http.StatusCreated {
+			sessions++
+		}
+
+		count := sessionCount(t, tserver)
+		if count != sessions {
+			t.Fatalf(
+				"nick %q, username %q: want %d sessions, got %d",
+				step.nick, step.username, sessions, count,
+			)
+		}
+	}
+}
+
 func TestNamesShowsHostmask(t *testing.T) {
 	tserver := newTestServer(t)
 

internal/handlers/auth.go

@@ -8,7 +8,12 @@ import (
 	"sneak.berlin/go/neoirc/pkg/irc"
 )
 
-const minPasswordLength = 8
+// A session password is 8 to 72 bytes; bcrypt cannot hash
+// a longer one.
+const (
+	minPasswordLength = 8
+	maxPasswordLength = 72
+)
 
 // HandleLogin authenticates a user with nick and password.
 func (hdlr *Handlers) HandleLogin() http.HandlerFunc {
@@ -149,12 +154,13 @@ func (hdlr *Handlers) handlePass(
 
 	password := lines[0]
 
-	if len(password) < minPasswordLength {
+	if len(password) < minPasswordLength ||
+		len(password) > maxPasswordLength {
 		hdlr.respondIRCError(
 			writer, request, clientID, sessionID,
 			irc.ErrNeedMoreParams, nick,
 			[]string{irc.CmdPass},
-			"Password must be at least 8 characters",
+			"Password must be 8 to 72 bytes",
 		)
 
 		return

internal/handlers/export_test.go

@@ -0,0 +1,19 @@
+package handlers
+
+import (
+	"context"
+
+	"sneak.berlin/go/neoirc/internal/db"
+)
+
+// SetPollMessages makes HandleGetMessages read the client
+// output queue with poll in place of Database.PollMessages.
+func (hdlr *Handlers) SetPollMessages(
+	poll func(
+		ctx context.Context,
+		clientID, afterQueueID int64,
+		limit int,
+	) ([]db.IRCMessage, int64, error),
+) {
+	hdlr.pollMessages = poll
+}

internal/handlers/handlers.go

@@ -64,6 +64,16 @@ type Handlers struct {
 	loginLimiter  *ratelimit.Limiter
 	stats         *stats.Tracker
 	cancelCleanup context.CancelFunc
+
+	// pollMessages is Database.PollMessages, with which
+	// HandleGetMessages reads the client output queue. Tests
+	// replace it to act just after a read, or to make a read
+	// fail.
+	pollMessages func(
+		ctx context.Context,
+		clientID, afterQueueID int64,
+		limit int,
+	) ([]db.IRCMessage, int64, error)
 }
 
 // New creates a new Handlers instance.
@@ -95,6 +105,7 @@ func New(
 		hashcashVal:  hashcash.NewValidator(resource),
 		loginLimiter: ratelimit.New(loginRate, loginBurst),
 		stats:        params.Stats,
+		pollMessages: params.Database.PollMessages,
 	}
 
 	lifecycle.Append(fx.Hook{

internal/hashcash/hashcash.go

@@ -77,9 +77,13 @@ func NewValidator(resource string) *Validator {
 	return validator
 }
 
-// Validate checks a hashcash stamp. It returns nil if the
-// stamp is valid and has not been seen before.
-func (v *Validator) Validate(
+// Check returns nil if requiredBits is not positive, or if
+// the stamp is a well-formed, recently dated proof of work
+// for this resource with at least requiredBits. It does not
+// look at or change the set of spent stamps, so a request
+// can check its stamp first and Claim it after its other
+// checks.
+func (v *Validator) Check(
 	stamp string,
 	requiredBits int,
 ) error {
@@ -87,9 +91,49 @@ func (v *Validator) Validate(
 		return nil
 	}
 
+	_, err := v.check(stamp, requiredBits)
+
+	return err
+}
+
+// Claim checks the stamp as Check does and, when
+// requiredBits is positive, records it as spent until it
+// expires. It returns an error if the stamp is already
+// spent. Release gives a claimed stamp back.
+func (v *Validator) Claim(
+	stamp string,
+	requiredBits int,
+) error {
+	if requiredBits <= 0 {
+		return nil
+	}
+
+	stampTime, err := v.check(stamp, requiredBits)
+	if err != nil {
+		return err
+	}
+
+	return v.checkAndRecordStamp(stamp, stampTime)
+}
+
+// Release forgets a claimed stamp so that it can be claimed
+// again, for a request that failed after its Claim.
+// Releasing a stamp that is not claimed does nothing.
+func (v *Validator) Release(stamp string) {
+	v.mu.Lock()
+	defer v.mu.Unlock()
+
+	delete(v.spent, stamp)
+}
+
+// check returns the stamp's date if Check accepts it.
+func (v *Validator) check(
+	stamp string,
+	requiredBits int,
+) (time.Time, error) {
 	parts := strings.Split(stamp, ":")
 	if len(parts) != stampFields {
-		return fmt.Errorf(
+		return time.Time{}, fmt.Errorf(
 			"%w: expected %d, got %d",
 			errInvalidFields, stampFields, len(parts),
 		)
@@ -104,25 +148,25 @@ func (v *Validator) Validate(
 		version, bitsStr, resource, requiredBits,
 	)
 	if err != nil {
-		return err
+		return time.Time{}, err
 	}
 
 	stampTime, err := parseStampDate(dateStr)
 	if err != nil {
-		return err
+		return time.Time{}, err
 	}
 
 	err = validateTime(stampTime)
 	if err != nil {
-		return err
+		return time.Time{}, err
 	}
 
 	err = validateProof(stamp, requiredBits)
 	if err != nil {
-		return err
+		return time.Time{}, err
 	}
 
-	return v.checkAndRecordStamp(stamp, stampTime)
+	return stampTime, nil
 }
 
 func (v *Validator) validateHeader(

internal/hashcash/hashcash_test.go

@@ -85,7 +85,7 @@ func TestMintAndValidate(t *testing.T) {
 		t, testBits, "test-resource", todayDate(),
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err != nil {
 		t.Fatalf("valid stamp rejected: %v", err)
 	}
@@ -99,17 +99,74 @@ func TestReplayDetection(t *testing.T) {
 		t, testBits, "test-resource", todayDate(),
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err != nil {
 		t.Fatalf("first use failed: %v", err)
 	}
 
-	err = validator.Validate(stamp, testBits)
+	err = validator.Claim(stamp, testBits)
 	if err == nil {
 		t.Fatal("replay not detected")
 	}
 }
 
+// TestCheckDoesNotSpendStamp checks that a stamp Check
+// accepts can still be claimed, and only once, and that
+// Check still accepts it once it is spent.
+func TestCheckDoesNotSpendStamp(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	stamp := mintStampWithDate(
+		t, testBits, "test-resource", todayDate(),
+	)
+
+	for range 2 {
+		err := validator.Check(stamp, testBits)
+		if err != nil {
+			t.Fatalf("valid stamp rejected: %v", err)
+		}
+	}
+
+	err := validator.Claim(stamp, testBits)
+	if err != nil {
+		t.Fatalf("claim after check failed: %v", err)
+	}
+
+	err = validator.Claim(stamp, testBits)
+	if err == nil {
+		t.Fatal("replay not detected")
+	}
+
+	err = validator.Check(stamp, testBits)
+	if err != nil {
+		t.Fatalf("spent stamp rejected by Check: %v", err)
+	}
+}
+
+// TestReleasedStampCanBeClaimedAgain checks that Release
+// gives a claimed stamp back.
+func TestReleasedStampCanBeClaimedAgain(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	stamp := mintStampWithDate(
+		t, testBits, "test-resource", todayDate(),
+	)
+
+	err := validator.Claim(stamp, testBits)
+	if err != nil {
+		t.Fatalf("first claim failed: %v", err)
+	}
+
+	validator.Release(stamp)
+
+	err = validator.Claim(stamp, testBits)
+	if err != nil {
+		t.Fatalf("claim after release failed: %v", err)
+	}
+}
+
 func TestResourceMismatch(t *testing.T) {
 	t.Parallel()
 
@@ -118,7 +175,7 @@ func TestResourceMismatch(t *testing.T) {
 		t, testBits, "wrong-resource", todayDate(),
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err == nil {
 		t.Fatal("expected resource mismatch error")
 	}
@@ -129,7 +186,7 @@ func TestInvalidStampFormat(t *testing.T) {
 
 	validator := hashcash.NewValidator("test-resource")
 
-	err := validator.Validate(
+	err := validator.Claim(
 		"not:a:valid:stamp", testBits,
 	)
 	if err == nil {
@@ -146,7 +203,7 @@ func TestBadVersion(t *testing.T) {
 		testBits, todayDate(), "test-resource",
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err == nil {
 		t.Fatal("expected bad version error")
 	}
@@ -162,7 +219,7 @@ func TestInsufficientDifficulty(t *testing.T) {
 		todayDate(), "test-resource",
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err == nil {
 		t.Fatal("expected insufficient bits error")
 	}
@@ -178,7 +235,7 @@ func TestExpiredStamp(t *testing.T) {
 		t, testBits, "test-resource", oldDate,
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err == nil {
 		t.Fatal("expected expired stamp error")
 	}
@@ -189,9 +246,14 @@ func TestZeroBitsSkipsValidation(t *testing.T) {
 
 	validator := hashcash.NewValidator("test-resource")
 
-	err := validator.Validate("garbage", 0)
+	err := validator.Check("garbage", 0)
 	if err != nil {
-		t.Fatalf("zero bits should skip: %v", err)
+		t.Fatalf("zero bits should skip the check: %v", err)
+	}
+
+	err = validator.Claim("garbage", 0)
+	if err != nil {
+		t.Fatalf("zero bits should skip the claim: %v", err)
 	}
 }
 
@@ -204,7 +266,7 @@ func TestLongDateFormat(t *testing.T) {
 		t, testBits, "test-resource", longDate,
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err != nil {
 		t.Fatalf("long date stamp rejected: %v", err)
 	}
@@ -219,7 +281,7 @@ func TestBadDateFormat(t *testing.T) {
 		testBits, "test-resource",
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err == nil {
 		t.Fatal("expected bad date error")
 	}
@@ -235,7 +297,7 @@ func TestMultipleUniqueStamps(t *testing.T) {
 			t, testBits, "test-resource", todayDate(),
 		)
 
-		err := validator.Validate(stamp, testBits)
+		err := validator.Claim(stamp, testBits)
 		if err != nil {
 			t.Fatalf("unique stamp rejected: %v", err)
 		}
@@ -251,7 +313,7 @@ func TestHigherBitsStillValid(t *testing.T) {
 		t, 4, "test-resource", todayDate(),
 	)
 
-	err := validator.Validate(stamp, testBits)
+	err := validator.Claim(stamp, testBits)
 	if err != nil {
 		t.Fatalf(
 			"higher-difficulty stamp rejected: %v",

internal/ircserver/commands.go

@@ -81,10 +81,10 @@ func (c *Conn) handleNick(
 	}
 
 	oldMask := c.hostmask()
-	oldNick := c.nick
+	oldNick := c.currentNick()
 
 	err := c.svc.ChangeNick(
-		ctx, c.sessionID, oldNick, newNick,
+		ctx, c.sessionID, c.clientID, oldNick, newNick,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -92,9 +92,10 @@ func (c *Conn) handleNick(
 		return
 	}
 
-	c.mu.Lock()
-	c.nick = newNick
-	c.mu.Unlock()
+	// Take the nick the session holds, not newNick: another
+	// client of the session may have changed it again since
+	// ChangeNick stored newNick.
+	c.loadSessionNick(ctx)
 
 	// Echo NICK change to the client on wire.
 	c.send(FormatMessage(oldMask, "NICK", newNick))
@@ -128,8 +129,8 @@ func (c *Conn) handlePrivmsg(
 	body, _ := json.Marshal([]string{text}) //nolint:errchkjson
 
 	if strings.HasPrefix(target, "#") {
-		_, _, err := c.svc.SendChannelMessage(
-			ctx, c.sessionID, c.nick,
+		_, err := c.svc.SendChannelMessage(
+			ctx, c.sessionID, c.clientID, c.currentNick(),
 			msg.Command, target, body, nil,
 		)
 		if err != nil {
@@ -137,7 +138,7 @@ func (c *Conn) handlePrivmsg(
 		}
 	} else {
 		result, err := c.svc.SendDirectMessage(
-			ctx, c.sessionID, c.nick,
+			ctx, c.sessionID, c.clientID, c.currentNick(),
 			msg.Command, target, body, nil,
 		)
 		if err != nil {
@@ -199,7 +200,7 @@ 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.currentNick(), channel, key,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -337,7 +338,7 @@ func (c *Conn) partChannel(
 	channel, reason string,
 ) {
 	err := c.svc.PartChannel(
-		ctx, c.sessionID, c.nick, channel, reason,
+		ctx, c.sessionID, c.clientID, c.currentNick(), channel, reason,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -401,7 +402,7 @@ 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.currentNick(), channel, newTopic,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -708,7 +709,7 @@ func (c *Conn) applyChannelModes(
 		c.send(FormatMessage(c.hostmask(), "MODE", params...))
 
 		c.svc.BroadcastMode(
-			ctx, c.nick, channel, chID, modeReply,
+			ctx, c.clientID, c.currentNick(), channel, chID, modeReply,
 		)
 	}
 }
@@ -1185,7 +1186,7 @@ func (c *Conn) handleKick(
 	}
 
 	err := c.svc.KickUser(
-		ctx, c.sessionID, c.nick,
+		ctx, c.sessionID, c.clientID, c.currentNick(),
 		channel, targetNick, reason,
 	)
 	if err != nil {
@@ -1216,17 +1217,16 @@ func (c *Conn) handlePassPostReg(
 	}
 
 	password := msg.Params[0]
-	if len(password) < minPasswordLen {
-		c.sendFromServer("NOTICE", c.nick,
-			"Password must be at least 8 characters",
-		)
-
+	if !c.checkPasswordLength(password) {
 		return
 	}
 
-	c.setPassword(ctx, password)
+	err := c.setPassword(ctx, password)
+	if err != nil {
+		return
+	}
 
-	c.sendFromServer("NOTICE", c.nick,
+	c.sendFromServer("NOTICE", c.currentNick(),
 		"Password set. You can reconnect using "+
 			"PASS <password> with your nick.",
 	)
@@ -1250,7 +1250,7 @@ func (c *Conn) handleInvite(
 	channel := msg.Params[1]
 
 	targetID, err := c.svc.InviteUser(
-		ctx, c.sessionID, c.nick, targetNick, channel,
+		ctx, c.sessionID, c.currentNick(), targetNick, channel,
 	)
 	if err != nil {
 		c.sendIRCError(err)
@@ -1262,14 +1262,13 @@ func (c *Conn) handleInvite(
 		irc.RplInviting, targetNick, channel,
 	)
 
-	// Send INVITE notice to target via service fan-out.
-	body, _ := json.Marshal( //nolint:errchkjson
-		[]string{"You have been invited to " + channel},
-	)
+	// Queue the INVITE to the target with the body the HTTP
+	// API uses.
+	body, _ := json.Marshal([]string{channel}) //nolint:errchkjson
 
 	_, _, _ = c.svc.FanOut( //nolint:dogsled // fire-and-forget broadcast
-		ctx, "INVITE", c.nick, targetNick, targetID, 0,
-		nil, body, nil, []int64{targetID},
+		ctx, "INVITE", c.currentNick(), targetNick, targetID, 0,
+		nil, body, nil, []int64{targetID}, 0,
 	)
 }
 

internal/ircserver/conn.go

@@ -27,6 +27,7 @@ const (
 	pingInterval    = 90 * time.Second
 	pongDeadline    = 30 * time.Second
 	minPasswordLen  = 8
+	maxPasswordLen  = 72 // bcrypt cannot hash a longer one
 	maxHashcashBits = 40
 )
 
@@ -62,6 +63,7 @@ type Conn struct {
 	registered bool
 	gotNick    bool
 	gotUser    bool
+	gotPass    bool
 	passWord   string
 
 	lastQueueID int64
@@ -70,7 +72,6 @@ type Conn struct {
 }
 
 func newConn(
-	ctx context.Context,
 	tcpConn net.Conn,
 	log *slog.Logger,
 	database *db.Database,
@@ -94,7 +95,6 @@ func newConn(
 		svc:       svc,
 		serverSfx: srvName,
 		remoteIP:  host,
-		hostname:  resolveHost(ctx, host),
 	}
 
 	conn.commands = conn.buildCommandMap()
@@ -212,12 +212,15 @@ func resolveHost(ctx context.Context, addr string) string {
 }
 
 // serve is the main loop for a single IRC client connection.
+// It first sets the client's hostname to what resolve returns
+// for the client's address.
 // Cancelling ctx when it returns stops the relay goroutine.
 // When nothing has been read for interval the client is sent
 // a PING, and when nothing is read within deadline after that
 // the connection is closed.
 func (c *Conn) serve(
 	ctx context.Context,
+	resolve func(ctx context.Context, addr string) string,
 	interval, deadline time.Duration,
 ) {
 	ctx, cancel := context.WithCancel(ctx)
@@ -226,6 +229,11 @@ func (c *Conn) serve(
 	// still end the session then.
 	defer c.cleanup(context.WithoutCancel(ctx))
 
+	// The hostname is looked up here, on this connection's
+	// goroutine, and not when the connection is accepted, so
+	// that a slow lookup holds up only this client.
+	c.hostname = resolve(ctx, c.remoteIP)
+
 	ping := time.AfterFunc(interval, func() {
 		c.send("PING :" + c.serverSfx)
 	})
@@ -305,6 +313,22 @@ func (c *Conn) currentNick() string {
 	return c.nick
 }
 
+// loadSessionNick sets c.nick to the nick the connection's
+// session holds in the database, read by session ID. The
+// connection's own NICK and the relay passing on a NICK line
+// both call it, and it reads and sets the nick under c.mu, so
+// whichever runs last leaves the connection on its session's
+// nick. If the read fails, c.nick is left as it is.
+func (c *Conn) loadSessionNick(ctx context.Context) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	nick, err := c.database.GetSessionNick(ctx, c.sessionID)
+	if err == nil {
+		c.nick = nick
+	}
+}
+
 // send writes a formatted IRC line to the connection.
 func (c *Conn) send(line string) {
 	c.sendWithin(writeTimeout, line)
@@ -337,7 +361,7 @@ func (c *Conn) sendNumeric(
 	code irc.IRCMessageType,
 	params ...string,
 ) {
-	nick := c.nick
+	nick := c.currentNick()
 	if nick == "" {
 		nick = "*"
 	}
@@ -361,9 +385,11 @@ func (c *Conn) sendFromServer(
 // hostmask returns the client's full hostmask
 // (nick!user@host).
 func (c *Conn) hostmask() string {
+	nick := c.currentNick()
+
 	user := c.username
 	if user == "" {
-		user = c.nick
+		user = nick
 	}
 
 	host := c.hostname
@@ -371,7 +397,7 @@ func (c *Conn) hostmask() string {
 		host = c.remoteIP
 	}
 
-	return c.nick + "!" + user + "@" + host
+	return nick + "!" + user + "@" + host
 }
 
 // handleMessage dispatches a parsed IRC message using
@@ -430,6 +456,7 @@ func (c *Conn) handlePreRegistration(
 		}
 
 		c.passWord = msg.Params[0]
+		c.gotPass = true
 	case irc.CmdNick:
 		if len(msg.Params) < 1 {
 			c.sendNumeric(
@@ -544,17 +571,20 @@ func (c *Conn) completeRegistration(ctx context.Context) {
 	// So that KILL, from either transport, can close it.
 	c.svc.RegisterWireConn(sessionID, c)
 
-	// If PASS was provided before registration, set the
-	// session password.
-	if c.passWord != "" && len(c.passWord) >= minPasswordLen {
-		c.setPassword(ctx, c.passWord)
-	}
-
 	// Send welcome burst.
 	c.deliverWelcome()
 	c.deliverLusers(ctx)
 	c.deliverMOTD()
 
+	// If PASS was given before registration, store its
+	// password now, after the welcome burst, so that a
+	// NOTICE refusing it reaches a registered client. A
+	// failure to store it is only logged, as it is for PASS
+	// after registration.
+	if c.gotPass && c.checkPasswordLength(c.passWord) {
+		_ = c.setPassword(ctx, c.passWord)
+	}
+
 	// Start the message relay goroutine.
 	go c.relayMessages(ctx)
 }
@@ -637,13 +667,33 @@ func (c *Conn) deliverMOTD() {
 	)
 }
 
-// setPassword sets a bcrypt password on the session.
-func (c *Conn) setPassword(ctx context.Context, pw string) {
+// checkPasswordLength reports whether pw is 8 to 72 bytes
+// long, and sends the client a NOTICE saying so when it is
+// not.
+func (c *Conn) checkPasswordLength(pw string) bool {
+	if len(pw) >= minPasswordLen && len(pw) <= maxPasswordLen {
+		return true
+	}
+
+	c.sendFromServer("NOTICE", c.currentNick(),
+		"Password must be 8 to 72 bytes",
+	)
+
+	return false
+}
+
+// setPassword sets a bcrypt password on the session, and
+// logs and returns the error when it was not stored.
+func (c *Conn) setPassword(ctx context.Context, pw string) error {
 	// Use the database's auth module to hash and store.
 	err := c.database.SetPassword(ctx, c.sessionID, pw)
 	if err != nil {
 		c.log.Error(
 			"failed to set password", "error", err,
 		)
+
+		return err
 	}
+
+	return nil
 }

internal/ircserver/export_test.go

@@ -15,7 +15,8 @@ import (
 
 // NewTestServer creates a Server suitable for testing, whose
 // connections use interval and deadline in place of
-// pingInterval and pongDeadline.
+// pingInterval and pongDeadline, and resolve in place of
+// resolveHost.
 // The caller must call Stop() when finished.
 func NewTestServer(
 	log *slog.Logger,
@@ -23,6 +24,7 @@ func NewTestServer(
 	database *db.Database,
 	brk *broker.Broker,
 	interval, deadline time.Duration,
+	resolve func(ctx context.Context, addr string) string,
 ) *Server {
 	globs := &globals.Globals{
 		Appname:   "neoirc",
@@ -44,9 +46,16 @@ func NewTestServer(
 
 		pingInterval: interval,
 		pongDeadline: deadline,
+		resolveHost:  resolve,
 	}
 }
 
+// ResolveHost is the reverse DNS lookup that a server made by
+// New does for each client.
+func ResolveHost(ctx context.Context, addr string) string {
+	return resolveHost(ctx, addr)
+}
+
 // Start exposes the unexported start method for tests.
 func (s *Server) Start(addr string) error {
 	return s.start(context.Background(), addr)
@@ -62,6 +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.
@@ -97,10 +111,7 @@ func NewTestConn(
 	tcpConn net.Conn,
 	nick string,
 ) *Conn {
-	conn := newConn(
-		context.Background(), tcpConn, log,
-		nil, nil, cfg, nil,
-	)
+	conn := newConn(tcpConn, log, nil, nil, cfg, nil)
 	conn.nick = nick
 
 	return conn

internal/ircserver/integration_test.go

@@ -1373,6 +1373,42 @@ func TestIntegrationInviteUserOnChannel(t *testing.T) {
 	)
 }
 
+// TestIntegrationInviteLine checks that an IRC listener user
+// invited by an IRC listener user, and then over the HTTP
+// API, gets an INVITE line from the inviter for the channel
+// each time.
+func TestIntegrationInviteLine(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	alice := env.dial(t)
+	alice.register("alice")
+	alice.joinAndDrain("#inv")
+
+	bob := env.dial(t)
+	bob.register("bob")
+
+	alice.sendAndExpect("INVITE bob #inv", " 341 ")
+
+	got := bob.readLine()
+	want := ":alice!alice@* INVITE bob #inv"
+
+	if got != want {
+		t.Errorf("from the IRC listener: got %q, want %q", got, want)
+	}
+
+	// The HTTP API queues an INVITE with the channel as its body.
+	env.queueMessage(t, "bob", "INVITE", "carol", "bob", []string{"#inv"})
+
+	got = bob.readLine()
+	want = ":carol!carol@* INVITE bob #inv"
+
+	if got != want {
+		t.Errorf("over the HTTP API: got %q, want %q", got, want)
+	}
+}
+
 // TestIntegrationModeSecretList checks that LIST shows a +s
 // channel only to its members.
 func TestIntegrationModeSecretList(t *testing.T) {

internal/ircserver/relay.go

@@ -27,17 +27,22 @@ func (c *Conn) relayMessages(ctx context.Context) {
 		default:
 		}
 
+		// Register with the broker before draining, so that a
+		// message queued after the drain has read the queue
+		// still signals waitCh.
+		waitCh := c.brk.Wait(c.sessionID)
+
 		// Drain any available messages.
 		delivered := c.drainQueue(ctx)
 
 		if delivered {
+			c.brk.Remove(c.sessionID, waitCh)
+
 			// Tight loop while there are messages.
 			continue
 		}
 
 		// Wait for notification or timeout.
-		waitCh := c.brk.Wait(c.sessionID)
-
 		select {
 		case <-waitCh:
 			// New message notification — loop back.
@@ -87,7 +92,7 @@ func (c *Conn) drainQueue(ctx context.Context) bool {
 //
 //nolint:cyclop // dispatch table
 func (c *Conn) deliverIRCMessage(
-	_ context.Context,
+	ctx context.Context,
 	msg *db.IRCMessage,
 ) {
 	command := msg.Command
@@ -115,7 +120,7 @@ func (c *Conn) deliverIRCMessage(
 	case command == irc.CmdPart:
 		c.deliverPart(msg, text)
 	case command == irc.CmdNick:
-		c.deliverNickChange(msg, text)
+		c.deliverNickChange(ctx, msg, text)
 	case command == irc.CmdQuit:
 		c.deliverQuitMsg(msg, text)
 	case command == irc.CmdTopic:
@@ -193,15 +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 + "@*"
@@ -214,16 +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
 
@@ -232,14 +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
 
@@ -252,18 +230,17 @@ func (c *Conn) deliverPart(msg *db.IRCMessage, text string) {
 	}
 }
 
-// deliverNickChange sends a NICK change notification.
+// deliverNickChange sends a NICK change notification. The
+// change may be its own session's, made from another client,
+// so the connection first takes the nick its session holds
+// now. It does not go by the line's old nick: the connection
+// may have taken that nick after another user gave it up.
 func (c *Conn) deliverNickChange(
+	ctx context.Context,
 	msg *db.IRCMessage,
 	newNick string,
 ) {
-	c.mu.Lock()
-	nick := c.nick
-	c.mu.Unlock()
-
-	if msg.From == nick {
-		return
-	}
+	c.loadSessionNick(ctx)
 
 	prefix := msg.From + "!" + msg.From + "@*"
 
@@ -275,14 +252,6 @@ 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 != "" {
@@ -335,16 +304,24 @@ func (c *Conn) deliverKickMsg(
 	}
 }
 
-// deliverInviteMsg sends an INVITE notification.
+// deliverInviteMsg sends an INVITE line from the inviter
+// for the channel named in text, or nothing when text names
+// no channel.
 func (c *Conn) deliverInviteMsg(
-	_ *db.IRCMessage,
+	msg *db.IRCMessage,
 	text string,
 ) {
+	if text == "" {
+		return
+	}
+
 	c.mu.Lock()
 	nick := c.nick
 	c.mu.Unlock()
 
-	c.sendFromServer("NOTICE", nick, text)
+	prefix := msg.From + "!" + msg.From + "@*"
+
+	c.send(FormatMessage(prefix, "INVITE", nick, text))
 }
 
 // deliverWallops sends a WALLOPS notification.

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)
 	}
@@ -47,14 +49,13 @@ func (env *testEnv) queueMessage(
 	env.brk.Notify(sessionID)
 }
 
-// TestRelayKeepsOneWaitChannel checks that an idle IRC
-// listener connection holds at most one broker wait channel
-// across several relay ticks, and none once it closes.
+// TestRelayKeepsOneWaitChannel checks that an IRC listener
+// connection holds at most one broker wait channel across
+// several relay ticks, both while idle and after the relay
+// has delivered it a message, and none once it closes.
 func TestRelayKeepsOneWaitChannel(t *testing.T) {
 	t.Parallel()
 
-	const idleTicks = 5
-
 	env := newTestEnv(t)
 
 	client := env.dial(t)
@@ -65,15 +66,17 @@ func TestRelayKeepsOneWaitChannel(t *testing.T) {
 		t.Fatalf("get session of idle: %v", err)
 	}
 
-	for tick := range idleTicks {
-		time.Sleep(ircserver.PollInterval)
+	env.checkOneWaitChannel(t, sessionID)
 
-		got := env.brk.ListenerCount(sessionID)
-		if got > 1 {
-			t.Fatalf("tick %d: got %d wait channels, want at most 1",
-				tick+1, got)
-		}
-	}
+	env.queueMessage(
+		t, "idle", "PRIVMSG", "carol", "idle", []string{"hello"},
+	)
+
+	client.readUntil(func(l string) bool {
+		return strings.Contains(l, "hello")
+	})
+
+	env.checkOneWaitChannel(t, sessionID)
 
 	err = client.conn.Close()
 	if err != nil {
@@ -92,6 +95,28 @@ func TestRelayKeepsOneWaitChannel(t *testing.T) {
 	}
 }
 
+// checkOneWaitChannel fails the test if the session
+// sessionID holds more than one broker wait channel at any of
+// several relay ticks.
+func (env *testEnv) checkOneWaitChannel(
+	t *testing.T,
+	sessionID int64,
+) {
+	t.Helper()
+
+	const ticks = 5
+
+	for tick := range ticks {
+		time.Sleep(ircserver.PollInterval)
+
+		got := env.brk.ListenerCount(sessionID)
+		if got > 1 {
+			t.Fatalf("tick %d: got %d wait channels, want at most 1",
+				tick+1, got)
+		}
+	}
+}
+
 // TestRelayMultiLineBody checks that each line of a PRIVMSG
 // or NOTICE body sent over the HTTP API reaches an IRC
 // listener user as its own line.
@@ -188,6 +213,38 @@ func TestRelayModeParameters(t *testing.T) {
 	}
 }
 
+// TestRelayInviteWithoutChannel checks that an INVITE whose
+// body names no channel sends the invited IRC listener user
+// no INVITE line.
+func TestRelayInviteWithoutChannel(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	bob := env.dial(t)
+	bob.register("bob")
+
+	// A nil body is stored as JSON null, which is not an array.
+	for _, body := range [][]string{nil, {}, {""}} {
+		env.queueMessage(t, "bob", "INVITE", "carol", "bob", body)
+	}
+
+	// The relay sends a user's queue in order, so this arrives
+	// after anything sent for the INVITEs above.
+	env.queueMessage(t, "bob", "PRIVMSG", "carol", "bob",
+		[]string{"the end"})
+
+	lines := bob.readUntil(func(l string) bool {
+		return strings.HasSuffix(l, " :the end")
+	})
+
+	for _, line := range lines {
+		if strings.Contains(line, " INVITE ") {
+			t.Errorf("got %q, want no INVITE line", line)
+		}
+	}
+}
+
 // TestRelayLineBreaks checks that a CR, LF or NUL in a stored
 // body line, key or mask never reaches an IRC listener user
 // as a line break, so no extra line arrives, and that a body
@@ -269,3 +326,372 @@ func TestRelayNickDiffersOnlyInCase(t *testing.T) {
 		}
 	}
 }
+
+// TestRelayOwnChangeOnce checks that an IRC listener user who
+// sets a topic, changes a channel mode or kicks gets one TOPIC,
+// MODE or KICK line for it, and so does the other member.
+func TestRelayOwnChangeOnce(t *testing.T) {
+	t.Parallel()
+
+	for _, step := range []struct {
+		command, line string
+	}{
+		{"TOPIC", "TOPIC #dup :new topic"},
+		{"MODE", "MODE #dup +m"},
+		{"KICK", "KICK #dup carl :bye"},
+	} {
+		t.Run(step.command, func(t *testing.T) {
+			t.Parallel()
+
+			env := newTestEnv(t)
+
+			alice := env.dial(t)
+			alice.register("alice")
+			alice.joinAndDrain("#dup")
+
+			carl := env.dial(t)
+			carl.register("carl")
+			carl.joinAndDrain("#dup")
+
+			alice.send(step.line)
+
+			// The reply to alice's next command comes after her
+			// command has finished, so her own copy comes before it.
+			beforePong := alice.sendAndExpect("PING :done", "PONG")
+
+			// The relay sends a user's queue in order, so a message
+			// queued now arrives after any relayed copy.
+			for nick, client := range map[string]*testClient{
+				"alice": alice, "carl": carl,
+			} {
+				env.queueMessage(
+					t, nick, "PRIVMSG", "dave", nick,
+					[]string{"after the change"},
+				)
+
+				lines := client.readUntil(func(l string) bool {
+					return strings.HasSuffix(l, " :after the change")
+				})
+
+				if client == alice {
+					lines = slices.Concat(beforePong, lines)
+				}
+
+				var changes []string
+
+				for _, line := range lines {
+					if strings.Contains(line, " "+step.command+" #dup ") {
+						changes = append(changes, line)
+					}
+				}
+
+				if len(changes) != 1 {
+					t.Errorf("%s got %q, want one %s line",
+						nick, changes, step.command)
+				}
+			}
+		})
+	}
+}
+
+// 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 sets up alice with aliceWithHTTPClient. 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()
+
+	ctx := t.Context()
+	env := newTestEnv(t)
+	alice, _, sessionID, httpClientID := aliceWithHTTPClient(t, env)
+
+	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
+}
+
+// aliceWithHTTPClient 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 returns her connection, bob's
+// connection, her session and her HTTP API client.
+func aliceWithHTTPClient(
+	t *testing.T, env *testEnv,
+) (*testClient, *testClient, int64, int64) {
+	t.Helper()
+
+	const password = "alicepass"
+
+	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(
+		t.Context(), "alice", password, "127.0.0.1", "localhost",
+	)
+	if err != nil {
+		t.Fatalf("log in as alice: %v", err)
+	}
+
+	return alice, bob, sessionID, httpClientID
+}
+
+// TestRelayNickChangeFromHTTPAPI checks that once alice's nick
+// is changed from her HTTP API client, her IRC listener
+// connection uses the new nick: what she then sends from it
+// reaches bob under the new nick.
+func TestRelayNickChangeFromHTTPAPI(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	alice, bob, sessionID, _ := aliceWithHTTPClient(t, env)
+
+	bob.joinAndDrain("#other")
+
+	// As the HTTP API does.
+	err := env.srv.Service().ChangeNick(
+		t.Context(), sessionID, 0, "alice", "alice2",
+	)
+	if err != nil {
+		t.Fatalf("change nick over the HTTP API: %v", err)
+	}
+
+	// Her connection has taken the new nick once it has sent her
+	// the change.
+	const change = ":alice!alice@* NICK alice2"
+
+	alice.readUntil(func(l string) bool { return l == change })
+	bob.readUntil(func(l string) bool { return l == change })
+
+	for _, step := range []struct {
+		line, want string
+	}{
+		{"PRIVMSG #chan :hi there", ":alice2!alice2@* PRIVMSG #chan :hi there"},
+		{"JOIN #other", ":alice2!alice2@* JOIN #other"},
+		{"NICK alice3", ":alice2!alice2@* NICK alice3"},
+	} {
+		alice.send(step.line)
+
+		got := bob.readLine()
+		if got != step.want {
+			t.Errorf("%s: got %q, want %q", step.line, got, step.want)
+		}
+	}
+}
+
+// TestRelayNickChangeKeepsTakenNick checks that an IRC
+// listener connection which takes a nick another user has
+// given up keeps it when that user's change reaches it
+// afterwards: what it then sends goes out under the nick its
+// session holds.
+func TestRelayNickChangeKeepsTakenNick(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	bob := env.dial(t)
+	bob.register("bob")
+	bob.sendAndExpect("NICK bob2", " NICK bob2")
+
+	alice := env.dial(t)
+	alice.register("alice")
+	alice.sendAndExpect("NICK bob", " NICK bob")
+	alice.joinAndDrain("#chan")
+
+	bob.joinAndDrain("#chan")
+
+	// Bob's change reaches alice only now, as it does when she
+	// takes his old nick before her connection has passed the
+	// change on. She holds bob now, so it is queued to bob.
+	env.queueMessage(t, "bob", "NICK", "bob", "", []string{"bob2"})
+
+	alice.readUntil(func(l string) bool {
+		return l == ":bob!bob@* NICK bob2"
+	})
+
+	alice.send("PRIVMSG #chan :hi there")
+
+	const want = ":bob!bob@* PRIVMSG #chan :hi there"
+
+	got := bob.readLine()
+	if got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}

internal/ircserver/server.go

@@ -52,6 +52,10 @@ type Server struct {
 	// same names, except in tests, which shorten them.
 	pingInterval time.Duration
 	pongDeadline time.Duration
+
+	// resolveHost is the function of the same name, except in
+	// tests, which replace it with one that blocks.
+	resolveHost func(ctx context.Context, addr string) string
 }
 
 // New creates a new IRC Server and registers its lifecycle
@@ -75,6 +79,7 @@ func New(
 
 		pingInterval: pingInterval,
 		pongDeadline: pongDeadline,
+		resolveHost:  resolveHost,
 	}
 
 	listenAddr := params.Config.IRCListenAddr
@@ -175,7 +180,7 @@ func (s *Server) acceptLoop(ctx context.Context) {
 		}
 
 		client := newConn(
-			ctx, tcpConn, s.log,
+			tcpConn, s.log,
 			s.database, s.brk, s.cfg, s.svc,
 		)
 
@@ -204,7 +209,10 @@ func (s *Server) acceptLoop(ctx context.Context) {
 				s.mu.Unlock()
 			}()
 
-			client.serve(ctx, s.pingInterval, s.pongDeadline)
+			client.serve(
+				ctx, s.resolveHost,
+				s.pingInterval, s.pongDeadline,
+			)
 		}()
 	}
 }

internal/ircserver/server_test.go

@@ -2,6 +2,7 @@ package ircserver_test
 
 import (
 	"bufio"
+	"context"
 	"crypto/rand"
 	"database/sql"
 	"errors"
@@ -11,6 +12,7 @@ import (
 	"os"
 	"runtime"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -90,6 +92,21 @@ func newTestEnvWithPingTimes(
 ) *testEnv {
 	t.Helper()
 
+	return newTestEnvWithResolver(
+		t, cfg, interval, deadline, ircserver.ResolveHost,
+	)
+}
+
+// newTestEnvWithResolver is newTestEnvWithPingTimes, except
+// that the server looks up a client's hostname with resolve.
+func newTestEnvWithResolver(
+	t *testing.T,
+	cfg *config.Config,
+	interval, deadline time.Duration,
+	resolve func(ctx context.Context, addr string) string,
+) *testEnv {
+	t.Helper()
+
 	// A random name, so that no other test environment, not
 	// even an earlier run of the same test, can share it.
 	dsn := fmt.Sprintf(
@@ -147,7 +164,7 @@ func newTestEnvWithPingTimes(
 	))
 
 	srv := ircserver.NewTestServer(
-		log, cfg, database, brk, interval, deadline,
+		log, cfg, database, brk, interval, deadline, resolve,
 	)
 
 	err = srv.Start(addr)
@@ -415,6 +432,49 @@ func TestRegistration(t *testing.T) {
 	assertContains(t, lines, " 001 ", "RPL_WELCOME")
 }
 
+// TestRegistrationWhileAnotherLookupIsPending checks that a
+// client is accepted and registered while the hostname lookup
+// of an earlier client has not returned, and that it
+// registers with the hostname its own lookup returned.
+func TestRegistrationWhileAnotherLookupIsPending(t *testing.T) {
+	t.Parallel()
+
+	const lookedUpHost = "client.example"
+
+	var lookups atomic.Int32
+
+	firstLookupStarted := make(chan struct{})
+
+	// The first lookup returns only when the server stops.
+	resolve := func(ctx context.Context, _ string) string {
+		if lookups.Add(1) == 1 {
+			close(firstLookupStarted)
+			<-ctx.Done()
+		}
+
+		return lookedUpHost
+	}
+
+	env := newTestEnvWithResolver(
+		t, &config.Config{ServerName: testServerName},
+		ircserver.PingInterval, ircserver.PongDeadline, resolve,
+	)
+
+	env.dial(t)
+
+	select {
+	case <-firstLookupStarted:
+	case <-time.After(testTimeout):
+		t.Fatal("the first client's lookup did not start")
+	}
+
+	lines := env.dial(t).register("second")
+	assertContains(
+		t, lines, "second!second@"+lookedUpHost,
+		"RPL_WELCOME with the looked-up hostname",
+	)
+}
+
 // TestEachTestEnvHasItsOwnDatabase checks that a test
 // environment starts on an empty database while another one
 // is still open.
@@ -585,8 +645,6 @@ func TestNewPingTimes(t *testing.T) {
 func TestIdleCleanupKeepsActiveUser(t *testing.T) {
 	t.Parallel()
 
-	const idleTimeout = 500 * time.Millisecond
-
 	env := newTestEnv(t)
 
 	active := env.dial(t)
@@ -595,13 +653,17 @@ func TestIdleCleanupKeepsActiveUser(t *testing.T) {
 	idle := env.dial(t)
 	idle.register("idle")
 
-	time.Sleep(idleTimeout)
+	// Both users were last seen before cutoff, and only active
+	// sends a command after it, so the result does not depend
+	// on how long the PONG takes to arrive.
+	cutoff := time.Now()
+
 	active.sendAndExpect("PING :still here", "PONG")
 
 	// The idle cleanup in internal/handlers removes exactly
 	// the users this returns.
 	stale, err := env.database.GetStaleOrphanSessions(
-		t.Context(), time.Now().Add(-idleTimeout),
+		t.Context(), cutoff,
 	)
 	if err != nil {
 		t.Fatalf("get stale sessions: %v", err)
@@ -1098,6 +1160,165 @@ func TestHandlePassPostRegistration(t *testing.T) {
 	)
 }
 
+// The shortest and longest password PASS accepts; bcrypt
+// cannot hash more than 72 bytes.
+const (
+	minPasswordBytes = 8
+	maxPasswordBytes = 72
+)
+
+// passwordLengthNotice is the NOTICE text for a password that
+// is too short or too long.
+const passwordLengthNotice = "Password must be 8 to 72 bytes"
+
+// passwordCase is a password a PASS test sends, and whether
+// the server should store it.
+type passwordCase struct {
+	name     string
+	password string
+	stored   bool
+}
+
+// passwordCases returns the passwords the PASS length tests
+// send: one of 8 to 72 bytes is stored and any other is
+// refused. The limit counts bytes: "é" is two bytes in UTF-8,
+// so 72 of them are refused.
+func passwordCases() []passwordCase {
+	return []passwordCase{
+		{"empty", "", false},
+		{"7 bytes", strings.Repeat("a", minPasswordBytes-1), false},
+		{"8 bytes", strings.Repeat("a", minPasswordBytes), true},
+		{"72 bytes", strings.Repeat("a", maxPasswordBytes), true},
+		{"73 bytes", strings.Repeat("a", maxPasswordBytes+1), false},
+		{"72 characters", strings.Repeat("é", maxPasswordBytes), false},
+	}
+}
+
+// assertStored fails the test unless nick can log in with
+// password exactly when stored is true.
+func assertStored(
+	t *testing.T, env *testEnv, nick, password string, stored bool,
+) {
+	t.Helper()
+
+	_, _, token, err := env.database.LoginUser(
+		t.Context(), nick, password, "127.0.0.1", "localhost",
+	)
+
+	loggedIn := err == nil && token != ""
+	if loggedIn != stored {
+		t.Errorf(
+			"log in as %s: logged in %v, want %v (error: %v)",
+			nick, loggedIn, stored, err,
+		)
+	}
+}
+
+// TestPassPostRegistrationLength checks that PASS after
+// registration stores and confirms a password of 8 to 72
+// bytes, and refuses any other with a NOTICE.
+func TestPassPostRegistrationLength(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	for i, tc := range passwordCases() {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			nick := fmt.Sprintf("postpass%d", i)
+			client := env.dial(t)
+
+			client.register(nick)
+			client.send("PASS :" + tc.password)
+
+			// The server answers commands in order, so its
+			// reply to PASS comes before the PONG.
+			lines := client.sendAndExpect("PING :after", "PONG")
+
+			reply := passwordLengthNotice
+			if tc.stored {
+				reply = "Password set"
+			}
+
+			assertContains(t, lines, reply, "reply to PASS")
+			assertStored(t, env, nick, tc.password, tc.stored)
+		})
+	}
+}
+
+// TestPassPostRegistrationNotStored checks that PASS is not
+// confirmed when the password could not be stored.
+func TestPassPostRegistrationNotStored(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("failpass")
+
+	_, err := env.database.GetDB().ExecContext(t.Context(),
+		`CREATE TRIGGER refuse_password
+		 BEFORE UPDATE OF password_hash ON sessions
+		 BEGIN SELECT RAISE(ABORT, 'refused'); END`,
+	)
+	if err != nil {
+		t.Fatalf("create trigger: %v", err)
+	}
+
+	client.send("PASS :mypassword123")
+
+	// The server answers commands in order, so anything it
+	// sent about PASS comes before the PONG.
+	lines := client.sendAndExpect("PING :after", "PONG")
+
+	assertNotContains(
+		t, lines, "Password set",
+		"confirmation of a password that was not stored",
+	)
+}
+
+// TestPassBeforeRegistrationLength checks that a PASS before
+// registration stores a password of 8 to 72 bytes, and that
+// any other is refused with a NOTICE once registration
+// completes.
+func TestPassBeforeRegistrationLength(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	for i, tc := range passwordCases() {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			nick := fmt.Sprintf("prepass%d", i)
+			client := env.dial(t)
+
+			client.send("PASS :" + tc.password)
+			client.register(nick)
+
+			// The password is checked after the welcome
+			// burst, which register reads; the PONG comes
+			// after that.
+			lines := client.sendAndExpect("PING :after", "PONG")
+
+			if tc.stored {
+				assertNotContains(
+					t, lines, passwordLengthNotice,
+					"refusal of a valid password",
+				)
+			} else {
+				assertContains(
+					t, lines, passwordLengthNotice,
+					"refusal after registration",
+				)
+			}
+
+			assertStored(t, env, nick, tc.password, tc.stored)
+		})
+	}
+}
+
 func TestPreRegistrationNotRegistered(t *testing.T) {
 	t.Parallel()
 

internal/server/export_test.go

@@ -1,6 +1,10 @@
 package server
 
-import "github.com/go-chi/chi/v5"
+import (
+	"net"
+
+	"github.com/go-chi/chi/v5"
+)
 
 // NewTestSPAServer creates a Server whose router serves only
 // the embedded web client.
@@ -10,3 +14,9 @@ func NewTestSPAServer() *Server {
 
 	return srv
 }
+
+// ServeUntilShutdown runs serveUntilShutdown, which serves the
+// HTTP server on listener, and returns when it does.
+func (srv *Server) ServeUntilShutdown(listener net.Listener) {
+	srv.serveUntilShutdown(listener)
+}

internal/server/server.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"net"
 	"net/http"
 	"os"
 	"os/signal"
@@ -39,6 +40,7 @@ type Params struct {
 	Config     *config.Config
 	Middleware *middleware.Middleware
 	Handlers   *handlers.Handlers
+	Shutdowner fx.Shutdowner
 }
 
 // Server is the main HTTP server.
@@ -66,7 +68,7 @@ func New(
 	}
 
 	lifecycle.Append(fx.Hook{
-		OnStart: func(_ context.Context) error {
+		OnStart: func(ctx context.Context) error {
 			srv.startupTime = time.Now()
 
 			// Build the router before OnStart returns, so srv can
@@ -78,9 +80,7 @@ func New(
 			// A closed stdout or stderr must not end the process.
 			signal.Ignore(syscall.SIGPIPE)
 
-			srv.startHTTP()
-
-			return nil
+			return srv.startHTTP(ctx)
 		},
 		OnStop: func(ctx context.Context) error {
 			srv.cleanShutdown(ctx)
@@ -162,15 +162,23 @@ func (srv *Server) configure() {
 	// Server configuration placeholder.
 }
 
-// startHTTP creates the HTTP server and serves it from a new
-// goroutine. srv.httpServer is set before that goroutine
-// starts and never changes, so it and cleanShutdown read it
-// without a lock.
-func (srv *Server) startHTTP() {
+// startHTTP binds the HTTP listen address, so that a port
+// that is taken fails startup, then serves the HTTP server
+// from a new goroutine. srv.httpServer is set before that
+// goroutine starts and never changes, so it and cleanShutdown
+// read it without a lock.
+func (srv *Server) startHTTP(ctx context.Context) error {
 	listenAddr := fmt.Sprintf(
 		":%d", srv.params.Config.Port,
 	)
 
+	var listenConfig net.ListenConfig
+
+	listener, err := listenConfig.Listen(ctx, "tcp", listenAddr)
+	if err != nil {
+		return fmt.Errorf("http listen: %w", err)
+	}
+
 	srv.httpServer = &http.Server{ //nolint:exhaustruct // optional fields
 		Addr:           listenAddr,
 		ReadTimeout:    httpReadTimeout,
@@ -179,16 +187,30 @@ func (srv *Server) startHTTP() {
 		Handler:        srv,
 	}
 
-	go srv.serveUntilShutdown()
+	go func() {
+		srv.serveUntilShutdown(listener)
+	}()
+
+	return nil
 }
 
-func (srv *Server) serveUntilShutdown() {
+// serveUntilShutdown serves the HTTP server on listener until
+// cleanShutdown stops it. If serving fails before then, it
+// stops the app with exit code 1.
+func (srv *Server) serveUntilShutdown(listener net.Listener) {
 	srv.log.Info(
 		"http begin listen", "listenaddr", srv.httpServer.Addr,
 	)
 
-	err := srv.httpServer.ListenAndServe()
-	if err != nil && !errors.Is(err, http.ErrServerClosed) {
-		srv.log.Error("listen error", "error", err)
+	err := srv.httpServer.Serve(listener)
+	if errors.Is(err, http.ErrServerClosed) {
+		return
+	}
+
+	srv.log.Error("listen error", "error", err)
+
+	err = srv.params.Shutdowner.Shutdown(fx.ExitCode(1))
+	if err != nil {
+		srv.log.Error("shutdown failed", "error", err)
 	}
 }

internal/server/server_test.go

@@ -1,3 +1,7 @@
+// Tests use a global viper instance for configuration,
+// making parallel execution unsafe.
+//
+//nolint:paralleltest
 package server_test
 
 import (
@@ -6,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"strconv"
+	"strings"
 	"testing"
 	"time"
 
@@ -40,8 +45,6 @@ const (
 // for a long poll the HTTP server is serving to finish, and
 // that the poll gets its response.
 func TestStopWaitsForRequestInProgress(t *testing.T) {
-	t.Parallel()
-
 	port := freePort(t)
 	addr := net.JoinHostPort("127.0.0.1", strconv.Itoa(port))
 
@@ -103,12 +106,114 @@ func TestStopWaitsForRequestInProgress(t *testing.T) {
 	}
 }
 
-// startApp starts the server with the dependencies
-// cmd/neoircd gives it, on a fresh in-memory database, with
-// the HTTP server listening on port.
+// TestStartFailsWhenHTTPPortIsTaken checks that starting the
+// app, which runs the start hook server.New registers,
+// returns an error naming the HTTP listen address when
+// something else is already listening on its port.
+func TestStartFailsWhenHTTPPortIsTaken(t *testing.T) {
+	var listenConfig net.ListenConfig
+
+	taken, err := listenConfig.Listen(t.Context(), "tcp", ":0")
+	if err != nil {
+		t.Fatalf("listen: %v", err)
+	}
+
+	t.Cleanup(func() { _ = taken.Close() })
+
+	tcpAddr, ok := taken.Addr().(*net.TCPAddr)
+	if !ok {
+		t.Fatalf("listener address %v is not TCP", taken.Addr())
+	}
+
+	app, _, _ := newApp(t, tcpAddr.Port)
+
+	err = app.Start(t.Context())
+	if err == nil {
+		app.RequireStop()
+		t.Fatal("the app started while its HTTP port was taken")
+	}
+
+	listenAddr := fmt.Sprintf(":%d", tcpAddr.Port)
+	if !strings.Contains(err.Error(), listenAddr) {
+		t.Errorf("start error %q does not name %s", err, listenAddr)
+	}
+}
+
+// TestServeFailureStopsApp checks that when serving HTTP fails
+// after the start hook has bound the listen address, the
+// server stops the app with exit code 1.
+func TestServeFailureStopsApp(t *testing.T) {
+	var srv *server.Server
+
+	app, _, _ := startApp(t, freePort(t), fx.Populate(&srv))
+
+	shutdowns := app.Wait()
+
+	srv.ServeUntilShutdown(closedListener(t))
+
+	select {
+	case shutdown := <-shutdowns:
+		if shutdown.ExitCode != 1 {
+			t.Errorf("exit code %d, want 1", shutdown.ExitCode)
+		}
+	default:
+		t.Error("the server did not stop the app")
+	}
+}
+
+// TestServeAfterStopDoesNotStopApp checks that serving HTTP
+// after the app has stopped, which ends at once because the
+// stop hook has shut the HTTP server down, does not stop the
+// app. Serving ends the same way on every normal stop.
+func TestServeAfterStopDoesNotStopApp(t *testing.T) {
+	var srv *server.Server
+
+	app, _, _ := startApp(t, freePort(t), fx.Populate(&srv))
+
+	shutdowns := app.Wait()
+
+	app.RequireStop()
+
+	srv.ServeUntilShutdown(closedListener(t))
+
+	select {
+	case shutdown := <-shutdowns:
+		t.Errorf(
+			"the server stopped the app with exit code %d",
+			shutdown.ExitCode,
+		)
+	default:
+	}
+}
+
+// startApp starts the app newApp builds, with the HTTP server
+// listening on port.
 func startApp(
 	t *testing.T,
 	port int,
+	options ...fx.Option,
+) (*fxtest.App, *broker.Broker, *db.Database) {
+	t.Helper()
+
+	app, brk, database := newApp(t, port, options...)
+
+	app.RequireStart()
+
+	// Stops the app if the test ends before stopping it.
+	t.Cleanup(app.RequireStop)
+
+	return app, brk, database
+}
+
+// newApp builds, without starting it, an app that runs the
+// server with the dependencies cmd/neoircd gives it, on a
+// fresh in-memory database, with the HTTP port set to port.
+// options are added to the app, for a test that needs more
+// from it than the broker and the database.
+func newApp(
+	t *testing.T,
+	port int,
+	options ...fx.Option,
 ) (*fxtest.App, *broker.Broker, *db.Database) {
 	t.Helper()
 
@@ -146,13 +251,9 @@ func startApp(
 		}),
 		fx.Invoke(func(*server.Server) {}),
 		fx.Populate(&brk, &database),
+		fx.Options(options...),
 	)
 
-	app.RequireStart()
-
-	// Stops the app if the test ends before stopping it.
-	t.Cleanup(app.RequireStop)
-
 	return app, brk, database
 }
 
@@ -161,6 +262,21 @@ func startApp(
 func freePort(t *testing.T) int {
 	t.Helper()
 
+	listener := closedListener(t)
+
+	tcpAddr, ok := listener.Addr().(*net.TCPAddr)
+	if !ok {
+		t.Fatalf("listener address %v is not TCP", listener.Addr())
+	}
+
+	return tcpAddr.Port
+}
+
+// closedListener returns a TCP listener that has already been
+// closed, so that accepting a connection on it fails.
+func closedListener(t *testing.T) net.Listener {
+	t.Helper()
+
 	var listenConfig net.ListenConfig
 
 	listener, err := listenConfig.Listen(
@@ -170,17 +286,12 @@ func freePort(t *testing.T) int {
 		t.Fatalf("listen: %v", err)
 	}
 
-	tcpAddr, ok := listener.Addr().(*net.TCPAddr)
-	if !ok {
-		t.Fatalf("listener address %v is not TCP", listener.Addr())
-	}
-
 	err = listener.Close()
 	if err != nil {
 		t.Fatalf("close listener: %v", err)
 	}
 
-	return tcpAddr.Port
+	return listener
 }
 
 // canConnect reports whether addr accepts a TCP connection.

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,
@@ -363,66 +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 validates the hashcash stamp of a
-// PRIVMSG to a +H channel, membership and moderation, then
-// fans out a message to all channel members except the
-// sender. Returns the database row ID, message UUID, and
-// any error. The dbID lets callers enqueue the same
-// message to the sender when echo is needed (HTTP
-// transport).
+// 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,
+// the sender's session included, skipping client
+// skipClientID as FanOut does. The stamp is checked after
+// the other checks so that a message they refuse does not
+// spend it. Returns the message UUID and any error.
 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
-	}
-
-	if command == irc.CmdPrivmsg {
-		err = s.checkChannelHashcash(
-			ctx, chID, channel, body, meta,
-		)
-		if err != nil {
-			return 0, "", err
-		}
+		return "", noSuchChannel
 	}
 
 	isMember, _ := s.db.IsChannelMember(
 		ctx, chID, sessionID,
 	)
 	if !isMember {
-		return 0, "", &IRCError{
+		return "", &IRCError{
 			irc.ErrCannotSendToChan,
 			[]string{channel},
 			"Cannot send to channel",
@@ -434,7 +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)",
@@ -451,7 +432,7 @@ func (s *Service) SendChannelMessage(
 		)
 
 		if !isOp && !isVoiced {
-			return 0, "", &IRCError{
+			return "", &IRCError{
 				irc.ErrCannotSendToChan,
 				[]string{channel},
 				"Cannot send to channel (+m)",
@@ -459,31 +440,40 @@ func (s *Service) SendChannelMessage(
 		}
 	}
 
-	memberIDs, _ := s.db.GetChannelMemberIDs(ctx, chID)
-	recipients := excludeSession(memberIDs, sessionID)
+	if command == irc.CmdPrivmsg {
+		err = s.checkChannelHashcash(
+			ctx, chID, channel, body, meta,
+		)
+		if err != nil {
+			return "", err
+		}
+	}
 
-	dbID, uuid, fanErr := s.FanOut(
+	memberIDs, _ := s.db.GetChannelMemberIDs(ctx, chID)
+
+	_, 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
-// message set on the target.
+// direct message to the target and the sender's session,
+// 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) {
@@ -505,7 +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) {
@@ -521,11 +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
-// does not match gets ERR_NOSUCHCHANNEL.
+// channel members, skipping client skipClientID as FanOut
+// 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) {
@@ -548,7 +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{
@@ -557,12 +548,12 @@ func (s *Service) JoinChannel(
 	}, nil
 }
 
-// PartChannel validates membership, broadcasts PART to
-// remaining members, removes the user, and cleans up empty
-// channels.
+// PartChannel validates membership, broadcasts PART to all
+// channel members, skipping client skipClientID as FanOut
+// 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)
@@ -586,12 +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
@@ -600,10 +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)
@@ -652,18 +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,
-// and cleans up empty channels.
+// membership, broadcasts the KICK to all channel members,
+// 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)
@@ -716,7 +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
@@ -797,10 +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)
@@ -821,7 +814,9 @@ func (s *Service) ChangeNick(
 		}
 	}
 
-	s.broadcastNickChange(ctx, sessionID, oldNick, newNick)
+	s.broadcastNickChange(
+		ctx, sessionID, skipClientID, oldNick, newNick,
+	)
 
 	return nil
 }
@@ -829,9 +824,10 @@ func (s *Service) ChangeNick(
 // BroadcastQuit parts the session from all its channels,
 // deletes it, and queues a QUIT to the users who shared a
 // channel with it, in one transaction, so that the QUIT is
-// queued before anyone else can take the nick. Of several
-// calls for one session at once, only the one that deletes
-// it sends the QUIT.
+// queued before anyone else can take the nick, and then
+// wakes those users' long polls. Of several calls for one
+// session at once, only the one that deletes it sends the
+// QUIT.
 func (s *Service) BroadcastQuit(
 	ctx context.Context,
 	sessionID int64,
@@ -853,6 +849,8 @@ func (s *Service) BroadcastQuit(
 
 // Logout deletes a client of the session and, if that was
 // the session's last client, does what BroadcastQuit does.
+// If that fails, nothing changes and Logout returns the
+// error.
 func (s *Service) Logout(
 	ctx context.Context,
 	sessionID, clientID int64,
@@ -1038,9 +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,
@@ -1050,7 +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,
 	)
 }
 
@@ -1302,11 +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(
@@ -1328,7 +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
 
@@ -1347,7 +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

@@ -24,6 +24,7 @@ import (
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/db"
 	"sneak.berlin/go/neoirc/internal/globals"
+	"sneak.berlin/go/neoirc/internal/hashcash"
 	"sneak.berlin/go/neoirc/internal/logger"
 	"sneak.berlin/go/neoirc/internal/service"
 	"sneak.berlin/go/neoirc/pkg/irc"
@@ -167,7 +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)
@@ -189,7 +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)
@@ -207,7 +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)
@@ -229,14 +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)
@@ -244,7 +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")
@@ -308,7 +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
 
@@ -334,7 +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)
@@ -447,7 +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)
@@ -456,12 +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
@@ -512,7 +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)
@@ -544,7 +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 {
@@ -591,7 +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)
 			}
@@ -601,7 +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)
 			}
@@ -616,7 +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)
 		}
@@ -677,7 +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
 	}
@@ -709,7 +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)
 	}
@@ -724,17 +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 {
@@ -753,7 +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)
 	}
@@ -772,7 +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 {
@@ -792,17 +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)
 	}
@@ -817,7 +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)
 	}
@@ -838,12 +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)
 	}
@@ -862,14 +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)
@@ -877,18 +878,14 @@ func TestSendChannelMessage(t *testing.T) {
 
 	body, _ := json.Marshal([]string{"hello world"}) //nolint:errchkjson
 
-	dbID, uuid, err := env.svc.SendChannelMessage(
-		ctx, sid1, "alice",
+	uuid, err := env.svc.SendChannelMessage(
+		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")
 	}
@@ -896,8 +893,8 @@ func TestSendChannelMessage(t *testing.T) {
 	// Non-member cannot send.
 	sid3 := createSession(ctx, t, env.db, "charlie")
 
-	_, _, err = env.svc.SendChannelMessage(
-		ctx, sid3, "charlie",
+	_, err = env.svc.SendChannelMessage(
+		ctx, sid3, 0, "charlie",
 		irc.CmdPrivmsg, "#chat", body, nil,
 	)
 	if err == nil {
@@ -913,14 +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)
@@ -962,7 +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
@@ -982,7 +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)
 	}
@@ -999,8 +996,8 @@ func TestSendChannelMessageChannelDeleted(t *testing.T) {
 
 	body, _ := json.Marshal([]string{"hi"}) //nolint:errchkjson
 
-	_, _, err = env.svc.SendChannelMessage(
-		ctx, sid, "alice", irc.CmdPrivmsg, "#gone", body, nil,
+	_, err = env.svc.SendChannelMessage(
+		ctx, sid, 0, "alice", irc.CmdPrivmsg, "#gone", body, nil,
 	)
 
 	var ircErr *service.IRCError
@@ -1018,14 +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)
@@ -1038,8 +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(
-		ctx, sid2, "bob",
+	_, err = env.svc.SendChannelMessage(
+		ctx, sid2, 0, "bob",
 		irc.CmdPrivmsg, "#modchat", body, nil,
 	)
 	if err == nil {
@@ -1047,8 +1044,8 @@ func TestSendChannelMessage_Moderated(t *testing.T) {
 	}
 
 	// Alice (operator) should succeed.
-	_, _, err = env.svc.SendChannelMessage(
-		ctx, sid1, "alice",
+	_, err = env.svc.SendChannelMessage(
+		ctx, sid1, 0, "alice",
 		irc.CmdPrivmsg, "#modchat", body, nil,
 	)
 	if err != nil {
@@ -1056,6 +1053,88 @@ func TestSendChannelMessage_Moderated(t *testing.T) {
 	}
 }
 
+// TestRefusedChannelMessageLeavesStampUnspent checks that a
+// PRIVMSG to a +H channel refused because the sender is not
+// a member, is banned, or has no voice on a +m channel does
+// not spend its hashcash stamp: the operator can then send
+// the same message with it.
+func TestRefusedChannelMessageLeavesStampUnspent(t *testing.T) {
+	const (
+		channel = "#paid"
+		bits    = 2
+	)
+
+	refusals := []struct {
+		name string
+		// refuse stops bob from sending to the channel.
+		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, 0, "bob", channel, "")
+		}},
+		{"banned", func(ctx context.Context, env *testEnv, chID, _ int64) error {
+			return env.db.AddChannelBan(ctx, chID, "bob!*@*", "alice")
+		}},
+		{"moderated", func(ctx context.Context, env *testEnv, chID, _ int64) error {
+			return env.svc.SetChannelFlag(ctx, chID, 'm', true)
+		}},
+	}
+
+	body, _ := json.Marshal([]string{"hello"}) //nolint:errchkjson
+
+	for _, refusal := range refusals {
+		t.Run(refusal.name, func(t *testing.T) {
+			env := newTestEnv(t)
+			ctx := t.Context()
+
+			aliceSID := createSession(ctx, t, env.db, "alice")
+			bobSID := createSession(ctx, t, env.db, "bob")
+
+			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, 0, "bob", channel, "")
+			if err != nil {
+				t.Fatalf("join bob: %v", err)
+			}
+
+			err = env.db.SetChannelHashcashBits(ctx, joined.ChannelID, bits)
+			if err != nil {
+				t.Fatalf("set +H: %v", err)
+			}
+
+			err = refusal.refuse(ctx, env, joined.ChannelID, bobSID)
+			if err != nil {
+				t.Fatalf("refuse bob: %v", err)
+			}
+
+			stamp := hashcash.MintChannelStamp(
+				bits, channel, hashcash.BodyHash(body),
+			)
+			meta, _ := json.Marshal(map[string]string{"hashcash": stamp})
+
+			_, err = env.svc.SendChannelMessage(
+				ctx, bobSID, 0, "bob", irc.CmdPrivmsg, channel, body, meta,
+			)
+
+			var ircErr *service.IRCError
+			if !errors.As(err, &ircErr) ||
+				ircErr.Code != irc.ErrCannotSendToChan {
+				t.Fatalf("bob: want ERR_CANNOTSENDTOCHAN, got %v", err)
+			}
+
+			_, err = env.svc.SendChannelMessage(
+				ctx, aliceSID, 0, "alice", irc.CmdPrivmsg, channel, body, meta,
+			)
+			if err != nil {
+				t.Fatalf("alice with the same stamp: %v", err)
+			}
+		})
+	}
+}
+
 func TestQueryUserMode(t *testing.T) {
 	env := newTestEnv(t)
 	ctx := t.Context()

web/src/app.jsx

@@ -58,13 +58,13 @@ async function mintHashcash(bits, resource) {
   }
 }
 
+// Requests are authenticated by the auth cookie, which the browser
+// sends on its own.
 function api(path, opts = {}) {
-  const token = localStorage.getItem("neoirc_token");
   const headers = {
     "Content-Type": "application/json",
     ...(opts.headers || {}),
   };
-  if (token) headers["Authorization"] = `Bearer ${token}`;
   const { signal, ...rest } = opts;
 
   return fetch(API + path, { ...rest, headers, signal }).then(async (r) => {
@@ -122,12 +122,11 @@ function LoginScreen({ onLogin }) {
         if (s.name) hashcashResourceRef.current = s.name;
       })
       .catch(() => {});
-    const saved = localStorage.getItem("neoirc_token");
-    if (saved) {
-      api("/state?initChannelState=1")
-        .then((u) => onLogin(u.nick, true))
-        .catch(() => localStorage.removeItem("neoirc_token"));
-    }
+    // Resume the session if the browser still holds a valid auth
+    // cookie; a 401 leaves the login form up.
+    api("/state?initChannelState=1")
+      .then((u) => onLogin(u.nick, true))
+      .catch(() => {});
     inputRef.current?.focus();
   }, []);
 
@@ -152,7 +151,6 @@ function LoginScreen({ onLogin }) {
         method: "POST",
         body: JSON.stringify(reqBody),
       });
-      localStorage.setItem("neoirc_token", res.token);
       onLogin(res.nick);
     } catch (err) {
       setError(err.data?.error || "Connection failed");
@@ -227,10 +225,9 @@ function UserList({ members, onNickClick }) {
   const regular = [];
 
   for (const m of members) {
-    const mode = m.mode || "";
-    if (mode === "o") {
+    if (m.isOperator) {
       ops.push(m);
-    } else if (mode === "v") {
+    } else if (m.isVoiced) {
       voiced.push(m);
     } else {
       regular.push(m);
@@ -303,11 +300,14 @@ function App() {
     nickRef.current = nick;
   }, [nick]);
 
-  // Persist joined channels.
+  // Persist joined channels, once logged in: before then only the
+  // Server tab exists, and writing would erase the saved channels
+  // that onLogin rejoins.
   useEffect(() => {
+    if (!loggedIn) return;
     const channels = tabs.filter((t) => t.type === "channel").map((t) => t.name);
     localStorage.setItem("neoirc_channels", JSON.stringify(channels));
-  }, [tabs]);
+  }, [loggedIn, tabs]);
 
   // Clear unread on tab switch.
   useEffect(() => {
@@ -366,7 +366,9 @@ function App() {
         command: msg.command,
       };
 
-      switch (msg.command) {
+      // A numeric reply carries its number in `code` and its name in
+      // `command`; other messages have no `code`.
+      switch (msg.code || msg.command) {
         case "PRIVMSG":
         case "NOTICE": {
           let text = body;
@@ -464,8 +466,18 @@ function App() {
 
           break;
         }
-        case "353": {
-          // RPL_NAMREPLY — parse mode prefixes from names list.
+        case "MODE": {
+          // The body is the change, with its value where it has one:
+          // ["+o bob"], ["+m"], ["+k", "secretpass"].
+          const modes = Array.isArray(msg.body) ? msg.body.join(" ") : "";
+          const text = `${msg.from} sets mode ${modes} on ${msg.to}`;
+          if (msg.to) addMessage(msg.to, { ...base, text, system: true });
+
+          break;
+        }
+        case 353: {
+          // RPL_NAMREPLY — each name is a hostmask (nick!user@host),
+          // prefixed with @ for an operator or + for a voiced member.
           if (
             Array.isArray(msg.params) &&
             msg.params.length >= 2 &&
@@ -477,21 +489,18 @@ function App() {
               : String(msg.body);
             const names = namesStr.split(/\s+/).filter(Boolean);
             const parsed = names.map((n) => {
-              if (n.startsWith("@")) {
-                return { nick: n.slice(1), mode: "o" };
-              }
-              if (n.startsWith("+")) {
-                return { nick: n.slice(1), mode: "v" };
-              }
+              const isOperator = n.startsWith("@");
+              const isVoiced = n.startsWith("+");
+              const hostmask = isOperator || isVoiced ? n.slice(1) : n;
 
-              return { nick: n, mode: "" };
+              return { nick: hostmask.split("!")[0], isOperator, isVoiced };
             });
             setMembers((prev) => ({ ...prev, [channel]: parsed }));
           }
 
           break;
         }
-        case "332": {
+        case 332: {
           // RPL_TOPIC — set topic from server.
           if (Array.isArray(msg.params) && msg.params.length >= 1) {
             const channel = msg.params[0];
@@ -503,7 +512,7 @@ function App() {
 
           break;
         }
-        case "322": {
+        case 322: {
           // RPL_LIST — channel, member count, topic.
           if (Array.isArray(msg.params) && msg.params.length >= 2) {
             const chName = msg.params[0];
@@ -518,7 +527,7 @@ function App() {
 
           break;
         }
-        case "323":
+        case 323:
           addMessage("Server", {
             ...base,
             text: body || "End of channel list",
@@ -526,7 +535,7 @@ function App() {
           });
 
           break;
-        case "352": {
+        case 352: {
           // RPL_WHOREPLY — channel, user, host, server, nick, flags.
           if (Array.isArray(msg.params) && msg.params.length >= 5) {
             const whoCh = msg.params[0];
@@ -541,7 +550,7 @@ function App() {
 
           break;
         }
-        case "315":
+        case 315:
           addMessage("Server", {
             ...base,
             text: body || "End of /WHO list",
@@ -549,20 +558,20 @@ function App() {
           });
 
           break;
-        case "311": {
-          // RPL_WHOISUSER — nick, user, host, *, realname.
-          if (Array.isArray(msg.params) && msg.params.length >= 1) {
-            const wiNick = msg.params[0];
+        case 311: {
+          // RPL_WHOISUSER — params nick, user, host, *; body realname.
+          if (Array.isArray(msg.params) && msg.params.length >= 3) {
+            const [wiNick, wiUser, wiHost] = msg.params;
             addMessage("Server", {
               ...base,
-              text: `${wiNick} (${body})`,
+              text: `${wiNick} is ${wiUser}@${wiHost} (${body})`,
               system: true,
             });
           }
 
           break;
         }
-        case "312": {
+        case 312: {
           // RPL_WHOISSERVER — nick, server, server info.
           if (Array.isArray(msg.params) && msg.params.length >= 2) {
             const wiNick = msg.params[0];
@@ -576,7 +585,33 @@ function App() {
 
           break;
         }
-        case "319": {
+        case 313: {
+          // RPL_WHOISOPERATOR — nick; body "is an IRC operator".
+          if (Array.isArray(msg.params) && msg.params.length >= 1) {
+            addMessage("Server", {
+              ...base,
+              text: `${msg.params[0]} ${body}`,
+              system: true,
+            });
+          }
+
+          break;
+        }
+        case 317: {
+          // RPL_WHOISIDLE — nick, idle seconds, signon time (Unix).
+          if (Array.isArray(msg.params) && msg.params.length >= 3) {
+            const [wiNick, idle, signon] = msg.params;
+            const signedOn = new Date(Number(signon) * 1000).toLocaleString();
+            addMessage("Server", {
+              ...base,
+              text: `${wiNick} has been idle ${idle}s, signed on ${signedOn}`,
+              system: true,
+            });
+          }
+
+          break;
+        }
+        case 319: {
           // RPL_WHOISCHANNELS — nick, channels.
           if (Array.isArray(msg.params) && msg.params.length >= 1) {
             const wiNick = msg.params[0];
@@ -589,7 +624,7 @@ function App() {
 
           break;
         }
-        case "318":
+        case 318:
           addMessage("Server", {
             ...base,
             text: body || "End of /WHOIS list",
@@ -597,9 +632,21 @@ function App() {
           });
 
           break;
-        case "375":
-        case "372":
-        case "376":
+        case 324: {
+          // RPL_CHANNELMODEIS — channel, mode string.
+          if (Array.isArray(msg.params) && msg.params.length >= 2) {
+            addMessage("Server", {
+              ...base,
+              text: `${msg.params[0]} modes: ${msg.params[1]}`,
+              system: true,
+            });
+          }
+
+          break;
+        }
+        case 375:
+        case 372:
+        case 376:
           addMessage("Server", { ...base, text: body, system: true });
 
           break;
@@ -637,6 +684,14 @@ function App() {
         } catch (err) {
           if (!alive) break;
           if (err.name === "AbortError") continue;
+          // 401: the session is gone (QUIT from another client, or
+          // expiry). Reloading drops this page's state and brings
+          // back the login screen.
+          if (err.status === 401) {
+            window.location.reload();
+
+            return;
+          }
           setConnected(false);
           await new Promise((r) => setTimeout(r, RECONNECT_DELAY));
         }
@@ -716,6 +771,11 @@ function App() {
 
   const onLogin = useCallback(
     async (userNick, isResumed) => {
+      // Read before setLoggedIn(true): from then on the effect under
+      // "Persist joined channels" writes the open channel tabs over it.
+      const saved = JSON.parse(
+        localStorage.getItem("neoirc_channels") || "[]",
+      );
       setNick(userNick);
       setLoggedIn(true);
       addSystemMessage("Server", `Connected as ${userNick}`);
@@ -740,9 +800,6 @@ function App() {
       }
 
       // Fresh session — join any previously saved channels.
-      const saved = JSON.parse(
-        localStorage.getItem("neoirc_channels") || "[]",
-      );
       for (const ch of saved) {
         try {
           await api("/messages", {
@@ -972,27 +1029,22 @@ function App() {
 
           break;
         }
+        // With no arguments MODE is a query. A change is one sign and
+        // letter, then its value where it takes one: +m, +o nick.
         const modeArgs = parts.slice(1);
-        if (modeArgs.length > 0) {
-          try {
-            await api("/messages", {
-              method: "POST",
-              body: JSON.stringify({
-                command: "MODE",
-                to: tab.name,
-                params: modeArgs,
-              }),
-            });
-          } catch (err) {
-            addSystemMessage(
-              "Server",
-              `Mode change failed: ${err.data?.error || "error"}`,
-            );
-          }
-        } else {
+        const body =
+          modeArgs.length > 0
+            ? { command: "MODE", to: tab.name, body: modeArgs }
+            : { command: "MODE", to: tab.name };
+        try {
+          await api("/messages", {
+            method: "POST",
+            body: JSON.stringify(body),
+          });
+        } catch (err) {
           addSystemMessage(
             "Server",
-            "Usage: /mode <+/-mode> [params]",
+            `MODE failed: ${err.data?.error || "error"}`,
           );
         }
 
@@ -1009,7 +1061,6 @@ function App() {
         } catch (e) {
           // Ignore.
         }
-        localStorage.removeItem("neoirc_token");
         localStorage.removeItem("neoirc_channels");
         window.location.reload();
 
@@ -1128,7 +1179,7 @@ function App() {
           "  /me action            — Send an action",
           "  /nick newnick         — Change your nickname",
           "  /topic [text]         — View or set channel topic",
-          "  /mode +/-flags        — Set channel modes",
+          "  /mode [+/-flag [arg]] — View or set channel modes",
           "  /motd                 — Display the message of the day",
           "  /list                 — List all channels",
           "  /who [#channel]       — List users in a channel",