nntp: handle 2-digit year "70" properly

Time::Local has the concept of a "rolling century" which is
defined at 50 years on either side of the current year.  Since
it's now 2020 and >50 years since the Unix epoch, the year "70"
gets interpreted by Time::Local as 2070-01-01 instead of
1970-01-01.

Since NNTP servers are unlikely to store messages from the
future, we'll feed 4-digit year to Time::Local::{timegm,timelocal}
and hopefully not have to worry about things until Y10K.

This fixes test failures on t/v2writable.t and t/nntpd.t since
2020-01-01.

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index 6845e8727d177fd83eef8398952957dbc9fde8c6..95c9082d807dcc8d16a19ac885fda0b223b87dac 100644 (file)
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -220,16 +220,17 @@ sub parse_time ($$;$) {
                $gmt =~ /\A(?:UTC|GMT)\z/i or die "GM invalid: $gmt";
                $gmt = 1;
        }
-       my @now = $gmt ? gmtime : localtime;
        my ($YYYY, $MM, $DD);
        if (bytes::length($date) == 8) { # RFC 3977 allows YYYYMMDD
                ($YYYY, $MM, $DD) = unpack('A4A2A2', $date);
        } else { # legacy clients send YYMMDD
-               ($YYYY, $MM, $DD) = unpack('A2A2A2', $date);
+               my $YY;
+               ($YY, $MM, $DD) = unpack('A2A2A2', $date);
+               my @now = $gmt ? gmtime : localtime;
                my $cur_year = $now[5] + 1900;
-               if ($YYYY > $cur_year) {
-                       $YYYY += int($cur_year / 1000) * 1000 - 100;
-               }
+               my $cur_cent = int($cur_year / 100) * 100;
+               $YYYY = (($YY + $cur_cent) > $cur_year) ?
+                       ($YY + 1900) : ($YY + $cur_cent);
        }
        if ($gmt) {
                timegm($ss, $mm, $hh, $DD, $MM - 1, $YYYY);

diff --git a/t/nntp.t b/t/nntp.t
index 11a175bb47d65c8c5b624e29b45dda4074731d9f..961b3d6af1e2da8b29aa3aec6cb1bb86e228d11a 100644 (file)
--- a/t/nntp.t
+++ b/t/nntp.t
@@ -69,11 +69,9 @@ use_ok 'PublicInbox::Inbox';
                my $m = join(' ', @_);
                my $ts = PublicInbox::NNTP::parse_time(@_);
                my @t = gmtime($ts);
-               my ($d, $t);
-               if (length($date) == 8) {
-                       ($d, $t) = split(' ', strftime('%Y%m%d %H%M%S', @t));
-               } else {
-                       ($d, $t) = split(' ', strftime('%g%m%d %H%M%S', @t));
+               my ($d, $t) = split(' ', strftime('%Y%m%d %H%M%S', @t));
+               if (length($date) != 8) { # Net::NNTP uses YYMMDD :<
+                       $d =~ s/^[0-9]{2}//;
                }
                is_deeply([$d, $t], [$date, $time], "roundtripped: $m");
                $ts;
@@ -81,13 +79,19 @@ use_ok 'PublicInbox::Inbox';
        my $x1 = time_roundtrip(qw(20141109 060606 GMT));
        my $x2 = time_roundtrip(qw(141109 060606 GMT));
        my $x3 = time_roundtrip(qw(930724 060606 GMT));
-
+       my $x5 = time_roundtrip(qw(710101 000000));
+       my $x6 = time_roundtrip(qw(720101 000000));
        SKIP: {
-               skip('YYMMDD test needs updating', 2) if (time > 0x7fffffff);
+               skip('YYMMDD test needs updating', 6) if (time > 0x7fffffff);
                # our world probably ends in 2038, but if not we'll try to
                # remember to update the test then
                is($x1, $x2, 'YYYYMMDD and YYMMDD parse identically');
                is(strftime('%Y', gmtime($x3)), '1993', '930724 was in 1993');
+
+               my $epoch = time_roundtrip(qw(700101 000000 GMT));
+               is($epoch, 0, 'epoch parsed correctly');
+               ok($x6 > $x5, '1972 > 1971');
+               ok($x5 > $epoch, '1971 > Unix epoch');
        }
 }