perl: call timegm and timelocal with 4-digit year
Amazingly, timegm(gmtime(0)) is only 0 before 2020 because perl's
timegm deviates from GNU timegm(3) in how it handles years.
man Time::Local says
Whenever possible, use an absolute four digit year instead.
with a detailed explanation about ambiguity of 2-digit years above that.
Even though this ambiguity is error-prone with >50% of users getting it
wrong, it has been like this for 20+ years, so we just use 4-digit years
everywhere to be on the safe side.
We add some extra logic to cvsimport because it allows 2-digit year
input and interpreting an 18 as 1918 can be avoided easily and safely.
Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/perl/Git.pm b/perl/Git.pm
index ffa09ac..df62518 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -534,7 +534,9 @@
sub get_tz_offset {
# some systems don't handle or mishandle %z, so be creative.
my $t = shift || time;
- my $gm = timegm(localtime($t));
+ my @t = localtime($t);
+ $t[5] += 1900;
+ my $gm = timegm(@t);
my $sign = qw( + + - )[ $gm <=> $t ];
return sprintf("%s%02d%02d", $sign, (gmtime(abs($t - $gm)))[2,1]);
}
