Subject: Re: [PATCH] git-svn: fix localtime=true on non-glibc environments

From: Junio C Hamano <[email-masked]>
Date: Wed, 25 Feb 2015 10:38:10 -0800

Ryuichi Kokubo <[email-masked]> writes:

> git svn uses POSIX::strftime('%s', $sec, $min, ...) to make unix epoch time.
> But lowercase %s formatting character is a GNU extention. This causes problem
> in git svn fetch --localtime on non-glibc systems, such as msys or cygwin.
> Using Time::Local::timelocal($sec, $min, ...) fixes it.
>
> Signed-off-by: Ryuichi Kokubo <[email-masked]>

Sounds sensible.

Because we already have "use Time::Local qw(...)" in perl/Git.pm
that is used by git-svn, we know the platforms that are capable
of running the current git-svn do have Time::Local available, so
I do not have worries about new dependency, either.

Eric?

>
> Notes:
>     lowercase %s format character in strftime is a GNU extension and not widely supported.
>     POSIX::strftime affected by underlying crt's strftime because POSIX::strftime just calls crt's one.
>     Time::Local is good function to replace POSIX::strftime because it's a perl core module function.
>     
>     Document about Time::Local.
>      http://perldoc.perl.org/Time/Local.html
>     
>     These are specifications of strftime.
>     
>     The GNU C Library Reference Manual.
>      http://www.gnu.org/software/libc/manual/html_node/Formatting-Calendar-Time.html
>     
>     perl POSIX module's strftime document. It does not have '%s'.
>      http://perldoc.perl.org/POSIX.html
>     
>     strftime document of Microsort Windows C Run-Time library.
>      https://msdn.microsoft.com/en-us/library/fe06s4ak.aspx
>     
>     The Open Group's old specification does not have '%s' too.
>      http://pubs.opengroup.org/onlinepubs/007908799/xsh/strftime.html
>     
>     On my environment, following problems happened.
>     - msys   : git svn fetch does not progress at all with perl.exe consuming CPU.
>     - cygwin : git svn fetch progresses but time stamp information is dropped.
>        Every commits have unix epoch timestamp.
>     
>     I would like to thank git developer and contibutors.
>     git helps me so much everyday.
>     Thank you.
> ---
>  perl/Git/SVN.pm |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/perl/Git/SVN.pm b/perl/Git/SVN.pm
> index 8e4af71..f243726 100644
> --- a/perl/Git/SVN.pm
> +++ b/perl/Git/SVN.pm
> @@ -14,6 +14,7 @@ use IPC::Open3;
>  use Memoize;  # core since 5.8.0, Jul 2002
>  use Memoize::Storable;
>  use POSIX qw(:signal_h);
> +use Time::Local;
>  
>  use Git qw(
>      command
> @@ -1332,7 +1333,7 @@ sub parse_svn_date {
>  		$ENV{TZ} = 'UTC';
>  
>  		my $epoch_in_UTC =
> -		    POSIX::strftime('%s', $S, $M, $H, $d, $m - 1, $Y - 1900);
> +		    Time::Local::timelocal($S, $M, $H, $d, $m - 1, $Y - 1900);
>  
>  		# Determine our local timezone (including DST) at the
>  		# time of $epoch_in_UTC.  $Git::SVN::Log::TZ stored the