[PATCH (BUGFIX)] gitweb: Fix handling of fractional timezones in parse_date

[Jakub Narebski <jnareb@gmail.com>]

Fractional timezones, like -0330 (NST used in Canada) or +0430
(Afghanistan, Iran DST), were not handled properly in parse_date; this
means values such as 'minute_local' and 'iso-tz' were not generated
correctly.

This was caused by two mistakes:

* sign of timezone was applied only to hour part of offset, and not
  as it should be also to minutes part (this affected only negative
  fractional timezones).

* 'int $h + $m/60' is 'int($h + $m/60)' and not 'int($h) + $m/60',
  so fractional part was discarded altogether ($h is hours, $m is
  minutes, which is always less than 60).


Note that positive fractional timezones +0430, +0530 and +1030 can be
found as authortime in git.git repository itself.

For example http://repo.or.cz/w/git.git/commit/88d50e7 had authortime
of "Fri, 8 Jan 2010 18:48:07 +0000 (23:48 +0530)", which is not marked
with 'atnight', when "git show 88d50e7" gives correct author date of
"Sat Jan 9 00:18:07 2010 +0530".

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
On Thu, 24 Mar 2011, Jakub Narebski wrote:
> On Thu, 24 Mar 2011, John 'Warthog9' Hawley wrote:

> > With each timezone being +1hr to the previous.  The code is capable of
> > handling fractional timezones, but those have not been added.

No, it isn't (see my other email).
 
> NOTE: I think that current gitweb code (parse_date / format_date) doesn't
> handle negative fractional timezones correctly.  
> 
>         $tz =~ m/^([+\-][0-9][0-9])([0-9][0-9])$/;
>         my $local = $epoch + ((int $1 + ($2/60)) * 3600);

This patch fixed this bug (actually two bugs ;-)).

> Though git.git repository doesn't contain negative fractional timezones...
> it does contain positive fractional timezones however.
> 
>   $ git log --pretty='%ai%n%ci' --all | cut -d' ' -f 3 | sort -n | uniq
> 
> Could anyone check it e.g. on Linux kernel repository?

Anyone?

 gitweb/gitweb.perl |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 0178633..256062e 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -2921,8 +2921,10 @@ sub parse_date {
 	$date{'iso-8601'}  = sprintf "%04d-%02d-%02dT%02d:%02d:%02dZ",
 	                     1900+$year, 1+$mon, $mday, $hour ,$min, $sec;
 
-	$tz =~ m/^([+\-][0-9][0-9])([0-9][0-9])$/;
-	my $local = $epoch + ((int $1 + ($2/60)) * 3600);
+	my ($tz_sign, $tz_hour, $tz_min) =
+		($tz =~ m/^([+\-])([0-9][0-9])([0-9][0-9])$/);
+	$tz_sign = ($tz_sign eq '-' ? -1 : +1);
+	my $local = $epoch + $tz_sign*($tz_hour + ($tz_min/60.0))*3600;
 	($sec, $min, $hour, $mday, $mon, $year, $wday, $yday) = gmtime($local);
 	$date{'hour_local'} = $hour;
 	$date{'minute_local'} = $min;
-- 
1.7.3