From 1abf35e1b5223de4c3da142eda6bf8b036272b34 Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@debian.org>
Date: Wed, 26 Nov 2014 11:29:14 +0000
Subject: [PATCH] Fix numeric comparisons with undef

---
 IkiWiki/Plugin/calendar.pm | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/IkiWiki/Plugin/calendar.pm b/IkiWiki/Plugin/calendar.pm
index 3d10b1e2e..23246757b 100644
--- a/IkiWiki/Plugin/calendar.pm
+++ b/IkiWiki/Plugin/calendar.pm
@@ -221,6 +221,10 @@ sub previousmonth($$$) {
 	my $month = shift;
 	my $archivebase = shift;
 
+	if (not exists $wikistate{calendar}{minyear}) {
+		$wikistate{calendar}{minyear} = $year;
+	}
+
 	my $pmonth = $month;
 	my $pyear  = $year;
 	while ((not exists $pagesources{"$archivebase/$pyear/" . sprintf("%02d", $pmonth)}) or ($pmonth == $month and $pyear == $year)) {
@@ -239,6 +243,10 @@ sub nextmonth($$$) {
 	my $month = shift;
 	my $archivebase = shift;
 
+	if (not exists $wikistate{calendar}{maxyear}) {
+		$wikistate{calendar}{maxyear} = $year;
+	}
+
 	my $nmonth = $month;
 	my $nyear  = $year;
 	while ((not exists $pagesources{"$archivebase/$nyear/" . sprintf("%02d", $nmonth)}) or ($nmonth == $month and $nyear == $year)) {