commit 3af4a1f76a207c8113cce7539b513a3af26dff8d
from: noodle <noodle@pastanoggin.com>
date: Fri Jan  9 17:27:01 2026 UTC

fix msgmax calculation and add an initial msgmax heuristic to fallback on

fixed incorrect msgmax calculation in response to WHO reply code 352, which
didn't account for the":nick!user@" part before hostname nor the space before
$priv.

additionally, an upcoming RSS feature would sometimes need to send news before
reading any messages back from server (and WHO reply code 352 might never return
or might not return on time), so a conservative fallback msgmax heurestic
calculation was added before the evasdrop loop. it uses a maximum hostname
length of 63 from RFC 2812 and accounts for the the non-ident tilde (~) that
might get prepended to username until we know what the actual hostname and
username are.

commit - 32d1199ddfacc2acda862cd1ad7032be610f2d37
commit + 3af4a1f76a207c8113cce7539b513a3af26dff8d
blob - bc434819232f19ca5d0cc7d99151faf0dbfa103e
blob + 9579989b001f202a240eeb511659dd4d28608520
--- mata_bot.pl
+++ mata_bot.pl
@@ -11,8 +11,10 @@ use constant {
 	LOG_WARN	=> 1,
 	LOG_DEBUG	=> 2,
 	CONNECT_TIMEOUT	=> 60,
+	CRLF		=> 2,		# RFC 2812
 	DEFAULT_PORT	=> 6667,
 	DEFAULT_TLS	=> 0,
+	HOSTMAX		=> 63,		# RFC 2812
 	IRCMAX		=> 512,
 	LAG_CHECK_TIME	=> 120,
 	MAX_LAG		=> 300,
@@ -298,6 +300,8 @@ sub evasdrop {
 
 	$pingsent = 0;
 	$priv = "PRIVMSG ${chan} :";
+	$msgmax = IRCMAX - length(":${MYNICK}!~${MYUSER}\@ ${priv}")
+		- HOSTMAX - CRLF; # conservative max message length heuristic
 	$msgtime = $pingtime = time;
 	while (1) {
 		if ($pingsent) {
@@ -319,19 +323,21 @@ sub evasdrop {
 			sendmsg($s, 'PONG :' . $1);
 		} elsif (/^:[^ ]+ PONG/) {
 			$pingsent = 0;
-		} elsif (/^:[^ ]+ 352 [^ ]+ [^ ]+ [^ ]+ ([^ ]+)/) {
-			# the extra 2 bytes account for \r\n
-			$msgmax = IRCMAX - length($1) - length($priv) - 2;
+		} elsif (
+		/^:[^ ]+ 352 ${MYNICK} [^ ]+ ([^ ]+) ([^ ]+) [^ ]+ (${MYNICK})/
+		) {
+			# refine maximum message length heuristic
+			$msgmax = IRCMAX - length(":${3}!${1}\@${2} ${priv}")
+				- CRLF;
 		} elsif (/^:([^ !#&][^ !]*)![^ \@]+\@[^ ]+ ${priv}(.+)$/) {
 			# respond to chan message
-			my $r;
+			my ($r, $len);
 
-			unless ($msgmax) {
-				logger(LOG_ERROR, 'could not calculate msgmax');
-				return;
-			}
 			$r = respond($1, $2, @$lists);
-			sendmsg($s, $priv . substr($r,0,$msgmax)) if length($r);
+			if ($len = length($r)) {
+				$r = substr($r,0,$msgmax-1).'-' if $len>$msgmax;
+				sendmsg($s, $priv . $r);
+			}
 		}
 	}
 }