From 5a348fe6f5dcb3d43697c97a0c3c9ad17fc2a3f4 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Mon, 11 Mar 2024 02:44:17 -0400
Subject: [PATCH 1/2] fix #2133

Don't record NICK and QUIT in history for invisible auditorium members
---
 irc/channel.go  | 16 ++++++++++++++++
 irc/client.go   |  9 ++++++---
 irc/nickname.go |  4 +++-
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/irc/channel.go b/irc/channel.go
index 586d80d1..fd3916d5 100644
--- a/irc/channel.go
+++ b/irc/channel.go
@@ -1622,6 +1622,22 @@ func (channel *Channel) auditoriumFriends(client *Client) (friends []*Client) {
 	return
 }
 
+// returns whether the client is visible to unprivileged users in the channel
+// (i.e., respecting auditorium mode)
+func (channel *Channel) clientIsVisible(client *Client) bool {
+	channel.stateMutex.RLock()
+	defer channel.stateMutex.RUnlock()
+
+	clientData, found := channel.members[client]
+	if !found {
+		return false
+	}
+	if !channel.flags.HasMode(modes.Auditorium) {
+		return true
+	}
+	return clientData.modes.HighestChannelUserMode() != modes.Mode(0)
+}
+
 // data for RPL_LIST
 func (channel *Channel) listData() (memberCount int, name, topic string) {
 	channel.stateMutex.RLock()
diff --git a/irc/client.go b/irc/client.go
index cc303e71..419955f2 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -1297,10 +1297,10 @@ func (client *Client) destroy(session *Session) {
 	}
 
 	var quitItem history.Item
-	var channels []*Channel
+	var quitHistoryChannels []*Channel
 	// use a defer here to avoid writing to mysql while holding the destroy semaphore:
 	defer func() {
-		for _, channel := range channels {
+		for _, channel := range quitHistoryChannels {
 			channel.AddHistoryItem(quitItem, details.account)
 		}
 	}()
@@ -1322,8 +1322,11 @@ func (client *Client) destroy(session *Session) {
 	// clean up channels
 	// (note that if this is a reattach, client has no channels and therefore no friends)
 	friends := make(ClientSet)
-	channels = client.Channels()
+	channels := client.Channels()
 	for _, channel := range channels {
+		if channel.clientIsVisible(client) {
+			quitHistoryChannels = append(quitHistoryChannels, channel)
+		}
 		for _, member := range channel.auditoriumFriends(client) {
 			friends.Add(member)
 		}
diff --git a/irc/nickname.go b/irc/nickname.go
index b180c005..698a8869 100644
--- a/irc/nickname.go
+++ b/irc/nickname.go
@@ -120,7 +120,9 @@ func performNickChange(server *Server, client *Client, target *Client, session *
 	}
 
 	for _, channel := range target.Channels() {
-		channel.AddHistoryItem(histItem, details.account)
+		if channel.clientIsVisible(client) {
+			channel.AddHistoryItem(histItem, details.account)
+		}
 	}
 
 	newCfnick := target.NickCasefolded()

From d1485d63456f24a7279d4217713b937a5b943d4b Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Mon, 11 Mar 2024 23:49:45 -0400
Subject: [PATCH 2/2] pointless optimization

---
 irc/channel.go  | 14 +++++++++-----
 irc/client.go   |  2 +-
 irc/nickname.go |  2 +-
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/irc/channel.go b/irc/channel.go
index fd3916d5..c6807a5c 100644
--- a/irc/channel.go
+++ b/irc/channel.go
@@ -1623,8 +1623,15 @@ func (channel *Channel) auditoriumFriends(client *Client) (friends []*Client) {
 }
 
 // returns whether the client is visible to unprivileged users in the channel
-// (i.e., respecting auditorium mode)
-func (channel *Channel) clientIsVisible(client *Client) bool {
+// (i.e., respecting auditorium mode). note that this assumes that the client
+// is a member; if the client is not, it may return true anyway
+func (channel *Channel) memberIsVisible(client *Client) bool {
+	// fast path, we assume they're a member so if this isn't an auditorium,
+	// they're visible:
+	if !channel.flags.HasMode(modes.Auditorium) {
+		return true
+	}
+
 	channel.stateMutex.RLock()
 	defer channel.stateMutex.RUnlock()
 
@@ -1632,9 +1639,6 @@ func (channel *Channel) clientIsVisible(client *Client) bool {
 	if !found {
 		return false
 	}
-	if !channel.flags.HasMode(modes.Auditorium) {
-		return true
-	}
 	return clientData.modes.HighestChannelUserMode() != modes.Mode(0)
 }
 
diff --git a/irc/client.go b/irc/client.go
index 419955f2..47aca273 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -1324,7 +1324,7 @@ func (client *Client) destroy(session *Session) {
 	friends := make(ClientSet)
 	channels := client.Channels()
 	for _, channel := range channels {
-		if channel.clientIsVisible(client) {
+		if channel.memberIsVisible(client) {
 			quitHistoryChannels = append(quitHistoryChannels, channel)
 		}
 		for _, member := range channel.auditoriumFriends(client) {
diff --git a/irc/nickname.go b/irc/nickname.go
index 698a8869..9373871d 100644
--- a/irc/nickname.go
+++ b/irc/nickname.go
@@ -120,7 +120,7 @@ func performNickChange(server *Server, client *Client, target *Client, session *
 	}
 
 	for _, channel := range target.Channels() {
-		if channel.clientIsVisible(client) {
+		if channel.memberIsVisible(client) {
 			channel.AddHistoryItem(histItem, details.account)
 		}
 	}