From 6a200ea639620695a34ca7dad6165c2829abc857 Mon Sep 17 00:00:00 2001
From: clawbot <clawbot@eeqj.de>
Date: Tue, 29 Sep 2026 10:48:48 +0000
Subject: [PATCH] Read the IRC client's nick under its lock in the relay

After registration each IRC connection runs a second goroutine that sends
queued messages to the client, and it read c.nick without holding c.mu.
The goroutine that reads client commands changes c.nick under c.mu when
the client sends NICK, so the race detector failed
TestIntegrationTwoClients. Every read of c.nick in relay.go now takes
c.mu. No other field that goroutine reads changes after it starts.

Model: opus-5-5
---
 internal/ircserver/relay.go | 48 ++++++++++++++++++++++++++++++-------
 1 file changed, 40 insertions(+), 8 deletions(-)

diff --git a/internal/ircserver/relay.go b/internal/ircserver/relay.go
index cb7d185..6d4195f 100644
--- a/internal/ircserver/relay.go
+++ b/internal/ircserver/relay.go
@@ -128,7 +128,11 @@ func (c *Conn) deliverIRCMessage(
 	default:
 		// Unknown command — deliver as server notice.
 		if text != "" {
-			c.sendFromServer("NOTICE", c.nick, text)
+			c.mu.Lock()
+			nick := c.nick
+			c.mu.Unlock()
+
+			c.sendFromServer("NOTICE", nick, text)
 		}
 	}
 }
@@ -158,8 +162,12 @@ func (c *Conn) deliverNumeric(
 		_ = json.Unmarshal(msg.Params, &params)
 	}
 
+	c.mu.Lock()
+	nick := c.nick
+	c.mu.Unlock()
+
 	allParams := make([]string, 0, 1+len(params)+1)
-	allParams = append(allParams, c.nick)
+	allParams = append(allParams, nick)
 	allParams = append(allParams, params...)
 
 	if text != "" {
@@ -177,8 +185,12 @@ 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 strings.EqualFold(from, c.nick) {
+	if strings.EqualFold(from, nick) {
 		return
 	}
 
@@ -192,9 +204,13 @@ 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 strings.EqualFold(msg.From, c.nick) {
+	if strings.EqualFold(msg.From, nick) {
 		return
 	}
 
@@ -206,7 +222,11 @@ func (c *Conn) deliverJoin(msg *db.IRCMessage) {
 
 // deliverPart sends a PART notification.
 func (c *Conn) deliverPart(msg *db.IRCMessage, text string) {
-	if strings.EqualFold(msg.From, c.nick) {
+	c.mu.Lock()
+	nick := c.nick
+	c.mu.Unlock()
+
+	if strings.EqualFold(msg.From, nick) {
 		return
 	}
 
@@ -227,7 +247,11 @@ func (c *Conn) deliverNickChange(
 	msg *db.IRCMessage,
 	newNick string,
 ) {
-	if strings.EqualFold(msg.From, c.nick) {
+	c.mu.Lock()
+	nick := c.nick
+	c.mu.Unlock()
+
+	if strings.EqualFold(msg.From, nick) {
 		return
 	}
 
@@ -241,7 +265,11 @@ func (c *Conn) deliverQuitMsg(
 	msg *db.IRCMessage,
 	text string,
 ) {
-	if strings.EqualFold(msg.From, c.nick) {
+	c.mu.Lock()
+	nick := c.nick
+	c.mu.Unlock()
+
+	if strings.EqualFold(msg.From, nick) {
 		return
 	}
 
@@ -302,7 +330,11 @@ func (c *Conn) deliverInviteMsg(
 	_ *db.IRCMessage,
 	text string,
 ) {
-	c.sendFromServer("NOTICE", c.nick, text)
+	c.mu.Lock()
+	nick := c.nick
+	c.mu.Unlock()
+
+	c.sendFromServer("NOTICE", nick, text)
 }
 
 // deliverMode sends a MODE change notification.