diff --git a/src/test/perl/PostgresVersion.pm b/src/test/perl/PostgresVersion.pm
index 4e764c36a55..884d0e949b9 100644
--- a/src/test/perl/PostgresVersion.pm
+++ b/src/test/perl/PostgresVersion.pm
@@ -120,9 +120,12 @@ sub _version_cmp
 
 	for (my $idx = 0;; $idx++)
 	{
-		return 0 unless (defined $an->[$idx] && defined $bn->[$idx]);
-		return $an->[$idx] <=> $bn->[$idx]
-		  if ($an->[$idx] <=> $bn->[$idx]);
+		return 0
+		  if ($idx >= @$an && $idx >= @$bn);
+		# treat a missing number as 0
+		my ($anum, $bnum) = ($an->[$idx] || 0, $bn->[$idx] || 0);
+		return $anum <=> $bnum
+		  if ($anum <=> $bnum);
 	}
 }