fix #1941

KLINE'd clients would produce a QUIT snotice without a corresponding
CONNECT snotice; explicitly suppress the QUIT snotice.

irc/client.go

 	hostname           string
 	invitedTo          map[string]channelInvite
 	isSTSOnly          bool
+	isKlined           bool // #1941: k-line kills are special-cased to suppress some triggered notices/events
 	languages          []string
 	lastActive         time.Time            // last time they sent a command that wasn't PONG or similar
 	lastSeen           map[string]time.Time // maps device ID (including "") to time of last received command
 	details := client.detailsNoMutex()
 	sessionRemoved := false
 	registered := client.registered
+	isKlined := client.isKlined
 	// XXX a temporary (reattaching) client can be marked alwaysOn when it logs in,
 	// but then the session attaches to another client and we need to clean it up here
 	alwaysOn := registered && client.alwaysOn
 	}
 
 	if registered {
-		client.server.snomasks.Send(sno.LocalQuits, fmt.Sprintf(ircfmt.Unescape("%s$r exited the network"), details.nick))
-		client.server.logger.Info("quit", fmt.Sprintf("%s is no longer on the server", details.nick))
+		if !isKlined {
+			client.server.snomasks.Send(sno.LocalQuits, fmt.Sprintf(ircfmt.Unescape("%s$r exited the network"), details.nick))
+			client.server.logger.Info("quit", fmt.Sprintf("%s is no longer on the server", details.nick))
+		}
 	}
 }
 

irc/getters.go

 	return
 }
 
+func (client *Client) setKlined() {
+	client.stateMutex.Lock()
+	client.isKlined = true
+	client.stateMutex.Unlock()
+}
+
 func (channel *Channel) Name() string {
 	channel.stateMutex.RLock()
 	defer channel.stateMutex.RUnlock()

irc/server.go

 	if !session.IP().IsLoopback() || session.isTor {
 		isBanned, info := server.klines.CheckMasks(c.AllNickmasks()...)
 		if isBanned {
+			c.setKlined()
 			c.Quit(info.BanMessage(c.t("You are banned from this server (%s)")), nil)
+			server.logger.Info("connect", "Client rejected by k-line", c.NickMaskString())
 			return true
 		}
 	}