Re-vendor the canonical files from sneak/prompts at dd4027b (closes #112)

The shared files are fetched from sneak/prompts dd4027b, with this
repository's own entries after the shared content in .gitignore,
.editorconfig and .dockerignore.

Lint and tests are Dockerfile phases (golangci-lint v2.14.0, Debian Go
1.24.13) that the build stage depends on, and the Makefile targets call
the script/ entrypoints. make fmt also formats Markdown with prettier.

Fixes for the new lint findings: the auth cookie is always Secure, an
IRC connection's relay goroutine stops when the connection closes, and
repeated strings are constants. neoirc-cli treats a plain-HTTP server on
localhost or a loopback address as secure, so local use keeps its session.

Whether the 60-second test cap covers building the test phase is open
on sneak/prompts issue 113.

Model: opus-5-5

internal/ircserver/commands.go

@@ -159,9 +159,7 @@ func (c *Conn) handleJoin(
 		return
 	}
 
-	channels := strings.Split(msg.Params[0], ",")
-
-	for _, chanName := range channels {
+	for chanName := range strings.SplitSeq(msg.Params[0], ",") {
 		chanName = strings.TrimSpace(chanName)
 
 		if !strings.HasPrefix(chanName, "#") {
@@ -305,9 +303,7 @@ func (c *Conn) handlePart(
 		reason = msg.Params[1]
 	}
 
-	channels := strings.Split(msg.Params[0], ",")
-
-	for _, ch := range channels {
+	for ch := range strings.SplitSeq(msg.Params[0], ",") {
 		ch = strings.TrimSpace(ch)
 		c.partChannel(ctx, ch, reason)
 	}
@@ -619,8 +615,8 @@ func (c *Conn) applyChannelModes(
 ) {
 	adding := true
 	argIdx := 0
-	applied := ""
-	appliedArgs := ""
+
+	var applied, appliedArgs strings.Builder
 
 	for _, modeChar := range modeStr {
 		var res modeResult
@@ -672,16 +668,13 @@ func (c *Conn) applyChannelModes(
 		argIdx += res.consumed
 
 		if !res.skip {
-			applied += res.applied
-			appliedArgs += res.appliedArgs
+			applied.WriteString(res.applied)
+			appliedArgs.WriteString(res.appliedArgs)
 		}
 	}
 
-	if applied != "" {
-		modeReply := applied
-		if appliedArgs != "" {
-			modeReply += appliedArgs
-		}
+	if applied.Len() > 0 {
+		modeReply := applied.String() + appliedArgs.String()
 
 		c.send(FormatMessage(
 			c.hostmask(), "MODE", channel, modeReply,

internal/ircserver/conn.go

@@ -62,7 +62,6 @@ type Conn struct {
 
 	lastQueueID int64
 	closed      bool
-	cancel      context.CancelFunc
 }
 
 func newConn(
@@ -151,8 +150,10 @@ func resolveHost(ctx context.Context, addr string) string {
 }
 
 // serve is the main loop for a single IRC client connection.
+// Cancelling ctx when it returns stops the relay goroutine.
 func (c *Conn) serve(ctx context.Context) {
-	ctx, c.cancel = context.WithCancel(ctx)
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
 	defer c.cleanup(ctx)
 
 	scanner := bufio.NewScanner(c.conn)
@@ -481,7 +482,7 @@ func (c *Conn) deliverMOTD() {
 		"- %s Message of the Day -", c.serverSfx,
 	))
 
-	for _, line := range strings.Split(motd, "\n") {
+	for line := range strings.SplitSeq(motd, "\n") {
 		c.sendNumeric(irc.RplMotd, "- "+line)
 	}
 

internal/ircserver/integration_test.go

@@ -282,6 +282,7 @@ func TestIntegrationTwoClients(t *testing.T) {
 
 	// Both nicks should appear in the name list.
 	foundBothNames := false
+
 	for _, line := range aliceNames {
 		if strings.Contains(line, " 353 ") &&
 			strings.Contains(line, "alice") &&
@@ -671,6 +672,7 @@ func TestIntegrationTwoClients(t *testing.T) {
 	})
 
 	foundPartErr := false
+
 	for _, line := range bobPartFail {
 		if strings.Contains(line, " 403 ") ||
 			strings.Contains(line, " 442 ") {
@@ -833,6 +835,7 @@ func TestIntegrationModeModerated(t *testing.T) {
 	})
 
 	foundModErr := false
+
 	for _, line := range bobLines {
 		if strings.Contains(line, " 404 ") ||
 			strings.Contains(line, " 482 ") {
@@ -859,6 +862,7 @@ func TestIntegrationModeModerated(t *testing.T) {
 	})
 
 	bob.send("PRIVMSG #modtest :voiced message")
+
 	aliceLines := alice.readUntil(func(l string) bool {
 		return strings.Contains(l, "voiced message")
 	})

internal/ircserver/parser_test.go

@@ -4,12 +4,18 @@ import (
 	"testing"
 
 	"sneak.berlin/go/neoirc/internal/ircserver"
+	"sneak.berlin/go/neoirc/pkg/irc"
 )
 
 //nolint:funlen // table-driven test
 func TestParseMessage(t *testing.T) {
 	t.Parallel()
 
+	const (
+		nick    = "alice"
+		channel = "#general"
+	)
+
 	tests := []struct {
 		name    string
 		input   string
@@ -24,10 +30,10 @@ func TestParseMessage(t *testing.T) {
 		},
 		{
 			name:  "simple command",
-			input: "PING",
+			input: irc.CmdPing,
 			want: &ircserver.Message{
 				Prefix:  "",
-				Command: "PING",
+				Command: irc.CmdPing,
 				Params:  nil,
 			},
 			wantNil: false,
@@ -38,7 +44,7 @@ func TestParseMessage(t *testing.T) {
 			want: &ircserver.Message{
 				Prefix:  "",
 				Command: "NICK",
-				Params:  []string{"alice"},
+				Params:  []string{nick},
 			},
 			wantNil: false,
 		},
@@ -57,8 +63,8 @@ func TestParseMessage(t *testing.T) {
 			input: "PRIVMSG #general :hello world",
 			want: &ircserver.Message{
 				Prefix:  "",
-				Command: "PRIVMSG",
-				Params:  []string{"#general", "hello world"},
+				Command: irc.CmdPrivmsg,
+				Params:  []string{channel, "hello world"},
 			},
 			wantNil: false,
 		},
@@ -68,7 +74,7 @@ func TestParseMessage(t *testing.T) {
 			want: &ircserver.Message{
 				Prefix:  "server.example.com",
 				Command: "001",
-				Params:  []string{"alice", "Welcome to IRC"},
+				Params:  []string{nick, "Welcome to IRC"},
 			},
 			wantNil: false,
 		},
@@ -79,7 +85,7 @@ func TestParseMessage(t *testing.T) {
 				Prefix:  "",
 				Command: "USER",
 				Params: []string{
-					"alice", "0", "*", "Alice Smith",
+					nick, "0", "*", "Alice Smith",
 				},
 			},
 			wantNil: false,
@@ -90,7 +96,7 @@ func TestParseMessage(t *testing.T) {
 			want: &ircserver.Message{
 				Prefix:  "",
 				Command: "JOIN",
-				Params:  []string{"#general"},
+				Params:  []string{channel},
 			},
 			wantNil: false,
 		},
@@ -99,17 +105,17 @@ func TestParseMessage(t *testing.T) {
 			input: "QUIT :leaving now",
 			want: &ircserver.Message{
 				Prefix:  "",
-				Command: "QUIT",
+				Command: irc.CmdQuit,
 				Params:  []string{"leaving now"},
 			},
 			wantNil: false,
 		},
 		{
 			name:  "quit without reason",
-			input: "QUIT",
+			input: irc.CmdQuit,
 			want: &ircserver.Message{
 				Prefix:  "",
-				Command: "QUIT",
+				Command: irc.CmdQuit,
 				Params:  nil,
 			},
 			wantNil: false,
@@ -120,7 +126,7 @@ func TestParseMessage(t *testing.T) {
 			want: &ircserver.Message{
 				Prefix:  "",
 				Command: "MODE",
-				Params:  []string{"#general"},
+				Params:  []string{channel},
 			},
 			wantNil: false,
 		},
@@ -131,7 +137,7 @@ func TestParseMessage(t *testing.T) {
 				Prefix:  "",
 				Command: "KICK",
 				Params: []string{
-					"#general", "bob", "misbehaving",
+					channel, "bob", "misbehaving",
 				},
 			},
 			wantNil: false,
@@ -141,8 +147,8 @@ func TestParseMessage(t *testing.T) {
 			input: "PRIVMSG #general :",
 			want: &ircserver.Message{
 				Prefix:  "",
-				Command: "PRIVMSG",
-				Params:  []string{"#general", ""},
+				Command: irc.CmdPrivmsg,
+				Params:  []string{channel, ""},
 			},
 			wantNil: false,
 		},
@@ -161,7 +167,7 @@ func TestParseMessage(t *testing.T) {
 			input: "PING :irc.example.com",
 			want: &ircserver.Message{
 				Prefix:  "",
-				Command: "PING",
+				Command: irc.CmdPing,
 				Params:  []string{"irc.example.com"},
 			},
 			wantNil: false,
@@ -173,7 +179,7 @@ func TestParseMessage(t *testing.T) {
 				Prefix:  "",
 				Command: "TOPIC",
 				Params: []string{
-					"#general",
+					channel,
 					"Welcome to the channel!",
 				},
 			},
@@ -237,6 +243,12 @@ func TestParseMessage(t *testing.T) {
 func TestFormatMessage(t *testing.T) {
 	t.Parallel()
 
+	const (
+		nick       = "alice"
+		channel    = "#general"
+		serverName = "server"
+	)
+
 	tests := []struct {
 		name    string
 		prefix  string
@@ -247,35 +259,35 @@ func TestFormatMessage(t *testing.T) {
 		{
 			name:    "simple command",
 			prefix:  "",
-			command: "PING",
+			command: irc.CmdPing,
 			params:  nil,
-			want:    "PING",
+			want:    irc.CmdPing,
 		},
 		{
 			name:    "with prefix",
-			prefix:  "server",
+			prefix:  serverName,
 			command: "PONG",
-			params:  []string{"server"},
+			params:  []string{serverName},
 			want:    ":server PONG server",
 		},
 		{
 			name:    "privmsg with trailing",
 			prefix:  "alice!alice@host",
-			command: "PRIVMSG",
-			params:  []string{"#general", "hello world"},
+			command: irc.CmdPrivmsg,
+			params:  []string{channel, "hello world"},
 			want:    ":alice!alice@host PRIVMSG #general :hello world",
 		},
 		{
 			name:    "numeric reply",
-			prefix:  "server",
+			prefix:  serverName,
 			command: "001",
-			params:  []string{"alice", "Welcome to IRC"},
+			params:  []string{nick, "Welcome to IRC"},
 			want:    ":server 001 alice :Welcome to IRC",
 		},
 		{
 			name:    "empty trailing",
-			prefix:  "server",
-			command: "PRIVMSG",
+			prefix:  serverName,
+			command: irc.CmdPrivmsg,
 			params:  []string{"#chan", ""},
 			want:    ":server PRIVMSG #chan :",
 		},
@@ -302,7 +314,7 @@ func TestParseFormatRoundTrip(t *testing.T) {
 	// parameter either contains a space (gets ':' prefix
 	// on format) or is a non-trailing single token.
 	lines := []string{
-		"PING",
+		irc.CmdPing,
 		"NICK alice",
 		"PRIVMSG #general :hello world",
 		"JOIN #general",

internal/ircserver/server.go

@@ -81,22 +81,24 @@ func New(
 // start begins listening for TCP connections.
 //
 //nolint:contextcheck // long-lived server ctx, not the short Fx one
-func (s *Server) start(_ context.Context, addr string) error {
-	ln, err := net.Listen("tcp", addr)
+func (s *Server) start(ctx context.Context, addr string) error {
+	var listenConfig net.ListenConfig
+
+	ln, err := listenConfig.Listen(ctx, "tcp", addr)
 	if err != nil {
 		return fmt.Errorf("irc listen: %w", err)
 	}
 
 	s.listener = ln
 
-	ctx, cancel := context.WithCancel(context.Background())
+	serverCtx, cancel := context.WithCancel(context.Background())
 	s.cancel = cancel
 
 	s.log.Info(
 		"irc server listening", "addr", addr,
 	)
 
-	go s.acceptLoop(ctx)
+	go s.acceptLoop(serverCtx)
 
 	return nil
 }

internal/ircserver/server_test.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net"
 	"os"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -71,7 +72,9 @@ func newTestEnv(t *testing.T) *testEnv {
 		MOTD:       "Welcome to test IRC",
 	}
 
-	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	var listenConfig net.ListenConfig
+
+	listener, err := listenConfig.Listen(t.Context(), "tcp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatalf("listen: %v", err)
 	}
@@ -116,10 +119,12 @@ func newTestEnv(t *testing.T) *testEnv {
 func (env *testEnv) dial(t *testing.T) *testClient {
 	t.Helper()
 
-	conn, err := net.DialTimeout(
+	dialer := net.Dialer{Timeout: testTimeout}
+
+	conn, err := dialer.DialContext(
+		t.Context(),
 		"tcp",
 		env.srv.Listener().Addr().String(),
-		testTimeout,
 	)
 	if err != nil {
 		t.Fatalf("dial: %v", err)
@@ -323,6 +328,7 @@ func TestPrivmsgBetweenClients(t *testing.T) {
 	bob.joinAndDrain("#chat")
 
 	alice.send("PRIVMSG #chat :hello bob!")
+
 	lines := bob.sendAndExpect("PING :sync", "hello bob!")
 	assertContains(t, lines, "hello bob!", "channel PRIVMSG")
 }
@@ -603,6 +609,56 @@ func TestNamesNonExistentChannel(t *testing.T) {
 	)
 }
 
+// TestRelayStopsWhenConnectionCloses checks that closing a
+// registered client's connection stops the goroutine that
+// relays its messages.
+//
+//nolint:paralleltest // counts every goroutine in the process
+func TestRelayStopsWhenConnectionCloses(t *testing.T) {
+	env := newTestEnv(t)
+	client := env.dial(t)
+
+	client.register("relaystop")
+	waitForRelayGoroutines(t, 1)
+
+	err := client.conn.Close()
+	if err != nil {
+		t.Fatalf("close: %v", err)
+	}
+
+	waitForRelayGoroutines(t, 0)
+}
+
+const (
+	stackDumpSize  = 1 << 20
+	relayCheckStep = 10 * time.Millisecond
+)
+
+// waitForRelayGoroutines waits until exactly want goroutines
+// are running the relay loop, and fails the test if that does
+// not happen within testTimeout.
+func waitForRelayGoroutines(t *testing.T, want int) {
+	t.Helper()
+
+	deadline := time.Now().Add(testTimeout)
+	stacks := make([]byte, stackDumpSize)
+
+	for {
+		n := runtime.Stack(stacks, true)
+		got := strings.Count(string(stacks[:n]), "(*Conn).relayMessages(")
+
+		if got == want {
+			return
+		}
+
+		if time.Now().After(deadline) {
+			t.Fatalf("relay goroutines: got %d, want %d", got, want)
+		}
+
+		time.Sleep(relayCheckStep)
+	}
+}
+
 func BenchmarkParseMessage(b *testing.B) {
 	line := ":nick!user@host PRIVMSG #channel :Hello, world!"