From 22ed6bb1f1a6b2da4b5e9f528b332a1611c29dc1 Mon Sep 17 00:00:00 2001
From: Daniel Oaks <daniel@danieloaks.net>
Date: Sun, 28 Apr 2019 01:50:43 +1000
Subject: [PATCH] Detect cap-notify clients better (as recommended by cap spec)

---
 irc/client_lookup_set.go | 16 ++++++++++++++++
 irc/server.go            |  2 +-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/irc/client_lookup_set.go b/irc/client_lookup_set.go
index 8a585ffd..6bdf74d2 100644
--- a/irc/client_lookup_set.go
+++ b/irc/client_lookup_set.go
@@ -207,6 +207,22 @@ func (clients *ClientManager) AllWithCaps(capabs ...caps.Capability) (sessions [
 	return
 }
 
+// AllWithCapsNotify returns all clients with the given capabilities, and that support cap-notify.
+func (clients *ClientManager) AllWithCapsNotify(capabs ...caps.Capability) (sessions []*Session) {
+	clients.RLock()
+	defer clients.RUnlock()
+	for _, client := range clients.byNick {
+		for _, session := range client.Sessions() {
+			capabs = append(capabs, caps.CapNotify)
+			if session.capabilities.HasAll(capabs...) || 302 <= session.capVersion {
+				sessions = append(sessions, session)
+			}
+		}
+	}
+
+	return
+}
+
 // FindAll returns all clients that match the given userhost mask.
 func (clients *ClientManager) FindAll(userhost string) (set ClientSet) {
 	set = make(ClientSet)
diff --git a/irc/server.go b/irc/server.go
index e4d2aadb..27f8952e 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -744,7 +744,7 @@ func (server *Server) applyConfig(config *Config, initial bool) (err error) {
 	removedCaps.Union(updatedCaps)
 
 	if !addedCaps.Empty() || !removedCaps.Empty() {
-		capBurstSessions = server.clients.AllWithCaps(caps.CapNotify)
+		capBurstSessions = server.clients.AllWithCapsNotify()
 
 		added[caps.Cap301] = addedCaps.String(caps.Cap301, CapValues)
 		added[caps.Cap302] = addedCaps.String(caps.Cap302, CapValues)