Re: What's cooking in git.git (Oct 2012, #09; Mon, 29)

From: Jeff King <peff@peff.net>
Date: Nov 2, 2012, 09:56 UTC
Message-ID: <20121102095632.GA30221@sigill.intra.peff.net>
In-Reply-To: <20121102094259.GA28414@sigill.intra.peff.net>

On Fri, Nov 02, 2012 at 05:43:00AM -0400, Jeff King wrote:

Show 12 quoted lines

> Yeah, I think that is it. IIRC, Ramsay is on cygwin, and I noticed this
> in perl 5.16's POSIX.xs:
>
> [...]
>    * (4) The CRT strftime() "%Z" implementation calls __tzset(). That
>    * calls CRT tzset(), but only the first time it is called, and in turn
>    * that uses CRT getenv("TZ") to retrieve the timezone info from the CRT
>    * local copy of the environment and hence gets the original setting as
>    * perl never updates the CRT copy when assigning to $ENV{TZ}.
> [...]
> I wonder if Ramsay has an older perl that does not do this special
> hackery right. I'll see if I can dig up where it first appeared.

It looks like that code went into perl 5.11.

I wonder, even with this fix, though, if we need to be calling tzset to reliably update from the environment. It sounds like it _should_ happen automatically, except that if the CRT is calling the internal tzset, it would not do the perl "grab from $ENV" magic. Calling tzset would make sure the internal TZ is up to date.

Ramsay, what happens with this patch on top?

diff --git a/git-cvsimport.perl b/git-cvsimport.perl
index ceb119d..4c44050 100755
--- a/git-cvsimport.perl
+++ b/git-cvsimport.perl
@@ -24,11 +24,12 @@ use File::Basename qw(basename dirname);
 use Time::Local;
 use IO::Socket;
 use IO::Pipe;
-use POSIX qw(strftime dup2 ENOENT);
+use POSIX qw(strftime tzset dup2 ENOENT);
 use IPC::Open2;
 
 $SIG{'PIPE'}="IGNORE";
 $ENV{'TZ'}="UTC";
+tzset();
 
 our ($opt_h,$opt_o,$opt_v,$opt_k,$opt_u,$opt_d,$opt_p,$opt_C,$opt_z,$opt_i,$opt_P, $opt_s,$opt_m,@opt_M,$opt_A,$opt_S,$opt_L, $opt_a, $opt_r, $opt_R);
 my (%conv_author_name, %conv_author_email, %conv_author_tz);
@@ -855,8 +856,10 @@ sub commit {
 	}
 
 	$ENV{'TZ'}=$author_tz;
+	tzset();
 	my $commit_date = strftime("%s %z", localtime($date));
 	$ENV{'TZ'}="UTC";
+	tzset();
 	$ENV{GIT_AUTHOR_NAME} = $author_name;
 	$ENV{GIT_AUTHOR_EMAIL} = $author_email;
 	$ENV{GIT_AUTHOR_DATE} = $commit_date;