[PATCH/RFC] git-svn: Add --convert-timezone option

[PATCH/RFC] git-svn: Add --convert-timezone option

[Pete Harlan]

By default git svn stores timestamps of fetched commits in
Subversion's UTC format, to facilitate interoperating with a
Subversion repository.

If you're using git svn to convert a repository to Git and aren't
interested in pushing Git commits back to Subversion, you can use this
option to store timestamps of fetched commits as though they were made
in the local timezone of the host on which git svn is run.  This makes
the times and timezones of a resulting "git log" agree with what "svn
log" shows for the same repository.

Signed-off-by: Pete Harlan <pgit@pcharlan.com>
---

This is a patch I've had floating around for a while.  I haven't
submitted it before because I find the solution ungainly.  There has
to be a better way to convert from one timezone to the other, but I
didn't run across it and now that I've converted away from Subversion
I'm sort of done thinking about it.  I'm submitting it now because
even in its current state it would have saved me some headache.

Also, I'm not sure I'm correct when asserting that converting
timezones like this will break Subversion interoperability.  Eric, if
that isn't true then I can remove that claim and resubmit.  If
converting timezones breaks nothing, then maybe it could even be the
default.

One improvement that I didn't bother to make would be to convert to
different local timezones based on author.  This change uses the
timezone of the machine running git-svn, which in my case was fine.
Using per-author timezones would be nice, but since parse_svn_date()
doesn't already know which author the date is associated with it would
be a more intrusive change.

My primary motivation in this was to reduce transition shock among our
development team.  The fewer ways "git log" looks unhelpfully
different than the old "svn log" the better; converting all commit
times into GMT wasn't going to look friendly.

Comments welcome.

--Pete

 Documentation/git-svn.txt              |    8 ++++
 contrib/completion/git-completion.bash |    2 +-
 git-svn.perl                           |   56 ++++++++++++++++++++++++++++++-
 3 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index 8d0c421..8811bf0 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -92,6 +92,14 @@ COMMANDS
 	.git/config file may be specified as an optional command-line
 	argument.

+--convert-timezones;;
+	Store Git commit times in the local timezone instead of UTC.  This
+	makes 'git-log' (even without --date=local) show the same times
+	that `svn log` would in the local timezone.
+
+This breaks interoperability with SVN, but may be cosmetically
+desirable when converting a repository from SVN to Git.
+
 'clone'::
 	Runs 'init' and 'fetch'.  It will automatically create a
 	directory based on the basename of the URL passed to it;
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 8ec782d..597ef3d 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1560,7 +1560,7 @@ _git_svn ()
 			--follow-parent --authors-file= --repack=
 			--no-metadata --use-svm-props --use-svnsync-props
 			--log-window-size= --no-checkout --quiet
-			--repack-flags --user-log-author $remote_opts
+			--repack-flags --user-log-author --convert-timezones $remote_opts
 			"
 		local init_opts="
 			--template= --shared= --trunk= --tags=
diff --git a/git-svn.perl b/git-svn.perl
index ad01e18..c2f600d 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -66,7 +66,7 @@ my ($_stdin, $_help, $_edit,
 	$_version, $_fetch_all, $_no_rebase,
 	$_merge, $_strategy, $_dry_run, $_local,
 	$_prefix, $_no_checkout, $_url, $_verbose,
-	$_git_format, $_commit_url, $_tag);
+	$_git_format, $_commit_url, $_tag, $_convert_timezones);
 $Git::SVN::_follow_parent = 1;
 my %remote_opts = ( 'username=s' => \$Git::SVN::Prompt::_username,
                     'config-dir=s' => \$Git::SVN::Ra::config_dir,
@@ -84,6 +84,7 @@ my %fc_opts = ( 'follow-parent|follow!' => \$Git::SVN::_follow_parent,
 		   \$Git::SVN::_repack_flags,
 		'use-log-author' => \$Git::SVN::_use_log_author,
 		'add-author-from' => \$Git::SVN::_add_author_from,
+		'convert-timezones' => \$_convert_timezones,
 		%remote_opts );

 my ($_trunk, $_tags, $_branches, $_stdlayout);
@@ -2526,12 +2527,63 @@ sub get_untracked {
 	\@out;
 }

+# parse_svn_date(DATE)
+# --------------------
+# Given a date (in UTC) from Subversion, return a string in the format
+# "<TZ Offset> <local date/time>" that Git will use.
+#
+# By default the parsed date will be in UTC for interoperating with
+# Subversion, but if $_convert_timezones is true we'll convert it to
+# the local timezone instead.
 sub parse_svn_date {
 	my $date = shift || return '+0000 1970-01-01 00:00:00';
 	my ($Y,$m,$d,$H,$M,$S) = ($date =~ /^(\d{4})\-(\d\d)\-(\d\d)T
 	                                    (\d\d)\:(\d\d)\:(\d\d).\d+Z$/x) or
 	                                 croak "Unable to parse date: $date\n";
-	"+0000 $Y-$m-$d $H:$M:$S";
+	my $parsed_date;    # Set next.
+
+	if ($_convert_timezones) {
+		# Translate the Subversion datetime to an epoch time.
+		# We need to switch ourselves to $date's timezone,
+		# UTC, for this.
+		my $oldEnvTZ = $ENV{TZ};
+		$ENV{TZ} = 'UTC';
+
+		my $epochUTC =
+		    POSIX::strftime ('%s', $S, $M, $H, $d, $m - 1, $Y - 1900);
+
+		# Determine our local timezone (including DST) at the
+		# time of $epochUTC.  $Git::SVN::Log::TZ stored the
+		# value of TZ, if any, at the time we were run.
+		if (defined $Git::SVN::Log::TZ) {
+			$ENV{TZ} = $Git::SVN::Log::TZ;
+		} else {
+			delete $ENV{TZ};
+		}
+
+		my $ourTZ =
+		    POSIX::strftime ('%Z', $S, $M, $H, $d, $m - 1, $Y - 1900);
+
+		# This converts $epochUTC into our local timezone.
+		my ($sec, $min, $hour, $mday, $mon, $year,
+		    $wday, $yday, $isdst) = localtime ($epochUTC);
+
+		$parsed_date = sprintf ('%s %04d-%02d-%02d %02d:%02d:%02d',
+					$ourTZ, $year + 1900, $mon + 1,
+					$mday, $hour, $min, $sec);
+
+		# Reset us to the timezone in effect when we entered
+		# this routine.
+		if (defined $oldEnvTZ) {
+			$ENV{TZ} = $oldEnvTZ;
+		} else {
+			delete $ENV{TZ};
+		}
+	} else {
+		$parsed_date = "+0000 $Y-$m-$d $H:$M:$S";
+	}
+
+	return $parsed_date;
 }

 sub check_author {
-- 
1.6.1.77.g56257

Re: [PATCH/RFC] git-svn: Add --convert-timezone option

[Eric Wong]

Pete Harlan <pgit@pcharlan.com> wrote:
> By default git svn stores timestamps of fetched commits in
> Subversion's UTC format, to facilitate interoperating with a
> Subversion repository.
> 
> If you're using git svn to convert a repository to Git and aren't
> interested in pushing Git commits back to Subversion, you can use this
> option to store timestamps of fetched commits as though they were made
> in the local timezone of the host on which git svn is run.  This makes
> the times and timezones of a resulting "git log" agree with what "svn
> log" shows for the same repository.
> 
> Signed-off-by: Pete Harlan <pgit@pcharlan.com>
> ---
> 
> This is a patch I've had floating around for a while.  I haven't
> submitted it before because I find the solution ungainly.  There has
> to be a better way to convert from one timezone to the other, but I
> didn't run across it and now that I've converted away from Subversion
> I'm sort of done thinking about it.  I'm submitting it now because
> even in its current state it would have saved me some headache.
> 
> Also, I'm not sure I'm correct when asserting that converting
> timezones like this will break Subversion interoperability.  Eric, if
> that isn't true then I can remove that claim and resubmit.  If
> converting timezones breaks nothing, then maybe it could even be the
> default.

Hi,

It'll break interoperability between multiple users of git-svn
tracking the same repo.  But several options already allow for
this (authors file, noMetdata, ...), so I'm fine with it as long
as it's optional.

> One improvement that I didn't bother to make would be to convert to
> different local timezones based on author.  This change uses the
> timezone of the machine running git-svn, which in my case was fine.
> Using per-author timezones would be nice, but since parse_svn_date()
> doesn't already know which author the date is associated with it would
> be a more intrusive change.

Could be an interesting idea, but on the other hand I doubt many people
would bother configuring the authors-file for it.

On a side note, for the total conversions I've done, I've found it
easier/faster/more bandwidth efficient to just forgo authors-file
entirely and use git-filter-branch after-the-fact.

> My primary motivation in this was to reduce transition shock among our
> development team.  The fewer ways "git log" looks unhelpfully
> different than the old "svn log" the better; converting all commit
> times into GMT wasn't going to look friendly.
> 
> Comments welcome.

My usual coding style nits apply (pretty much git (and Linux kernel)
standard coding style things, too).

No space between "function(arguments)".

lower_snake_case, especially for local variables.  mixedCase requires
more effort to read IMO.

More comments inline...

> --Pete
> 
>  Documentation/git-svn.txt              |    8 ++++
>  contrib/completion/git-completion.bash |    2 +-
>  git-svn.perl                           |   56 ++++++++++++++++++++++++++++++-
>  3 files changed, 63 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
> index 8d0c421..8811bf0 100644
> --- a/Documentation/git-svn.txt
> +++ b/Documentation/git-svn.txt
> @@ -92,6 +92,14 @@ COMMANDS
>  	.git/config file may be specified as an optional command-line
>  	argument.
> 
> +--convert-timezones;;

Is it "timezone" or "timezones" here?  I think "convert-timezone" is
more correct since we only use the local timezone, not different
ones for each author.  On the other hand, maybe "--localtime" is
an even better name for this option...

Any other opinions out there?

> +	Store Git commit times in the local timezone instead of UTC.  This
> +	makes 'git-log' (even without --date=local) show the same times
> +	that `svn log` would in the local timezone.
> +
> +This breaks interoperability with SVN, but may be cosmetically
> +desirable when converting a repository from SVN to Git.

Again, this only breaks interoperability with other users of git-svn
using the default configuration on the same repo.

>  'clone'::
>  	Runs 'init' and 'fetch'.  It will automatically create a
>  	directory based on the basename of the URL passed to it;
> diff --git a/git-svn.perl b/git-svn.perl
> index ad01e18..c2f600d 100755
> --- a/git-svn.perl
> +++ b/git-svn.perl
> @@ -66,7 +66,7 @@ my ($_stdin, $_help, $_edit,
>  	$_version, $_fetch_all, $_no_rebase,
>  	$_merge, $_strategy, $_dry_run, $_local,
>  	$_prefix, $_no_checkout, $_url, $_verbose,
> -	$_git_format, $_commit_url, $_tag);
> +	$_git_format, $_commit_url, $_tag, $_convert_timezones);

Not easy to tell (and apologies for that) but this new variable probably
belongs in the Git::SVN namespace.  I really need to find some time to
reorganize and split out the source to git-svn.

>  $Git::SVN::_follow_parent = 1;
>  my %remote_opts = ( 'username=s' => \$Git::SVN::Prompt::_username,
>                      'config-dir=s' => \$Git::SVN::Ra::config_dir,
> @@ -84,6 +84,7 @@ my %fc_opts = ( 'follow-parent|follow!' => \$Git::SVN::_follow_parent,
>  		   \$Git::SVN::_repack_flags,
>  		'use-log-author' => \$Git::SVN::_use_log_author,
>  		'add-author-from' => \$Git::SVN::_add_author_from,
> +		'convert-timezones' => \$_convert_timezones,
>  		%remote_opts );
> 
>  my ($_trunk, $_tags, $_branches, $_stdlayout);
> @@ -2526,12 +2527,63 @@ sub get_untracked {
>  	\@out;
>  }
> 
> +# parse_svn_date(DATE)
> +# --------------------
> +# Given a date (in UTC) from Subversion, return a string in the format
> +# "<TZ Offset> <local date/time>" that Git will use.
> +#
> +# By default the parsed date will be in UTC for interoperating with
> +# Subversion, but if $_convert_timezones is true we'll convert it to
> +# the local timezone instead.
>  sub parse_svn_date {
>  	my $date = shift || return '+0000 1970-01-01 00:00:00';
>  	my ($Y,$m,$d,$H,$M,$S) = ($date =~ /^(\d{4})\-(\d\d)\-(\d\d)T
>  	                                    (\d\d)\:(\d\d)\:(\d\d).\d+Z$/x) or
>  	                                 croak "Unable to parse date: $date\n";
> -	"+0000 $Y-$m-$d $H:$M:$S";
> +	my $parsed_date;    # Set next.
> +
> +	if ($_convert_timezones) {
> +		# Translate the Subversion datetime to an epoch time.
> +		# We need to switch ourselves to $date's timezone,
> +		# UTC, for this.
> +		my $oldEnvTZ = $ENV{TZ};
> +		$ENV{TZ} = 'UTC';
> +
> +		my $epochUTC =
> +		    POSIX::strftime ('%s', $S, $M, $H, $d, $m - 1, $Y - 1900);
> +
> +		# Determine our local timezone (including DST) at the
> +		# time of $epochUTC.  $Git::SVN::Log::TZ stored the
> +		# value of TZ, if any, at the time we were run.
> +		if (defined $Git::SVN::Log::TZ) {
> +			$ENV{TZ} = $Git::SVN::Log::TZ;
> +		} else {
> +			delete $ENV{TZ};
> +		}
> +
> +		my $ourTZ =
> +		    POSIX::strftime ('%Z', $S, $M, $H, $d, $m - 1, $Y - 1900);
> +
> +		# This converts $epochUTC into our local timezone.
> +		my ($sec, $min, $hour, $mday, $mon, $year,
> +		    $wday, $yday, $isdst) = localtime ($epochUTC);
> +
> +		$parsed_date = sprintf ('%s %04d-%02d-%02d %02d:%02d:%02d',
> +					$ourTZ, $year + 1900, $mon + 1,
> +					$mday, $hour, $min, $sec);

There's probably a reason you didn't use strftime here, or is there?
The stock Perl time/date handling functions have always frightened me,
so I'll just trust the (+|-) (1|1900) things are correct :)

-- 
Eric Wong

Re: [PATCH/RFC] git-svn: Add --convert-timezone option

[Pete Harlan]

Eric Wong wrote:
> Pete Harlan <pgit@pcharlan.com> wrote:
>> By default git svn stores timestamps of fetched commits in
>> Subversion's UTC format, to facilitate interoperating with a
>> Subversion repository.
>>
>> If you're using git svn to convert a repository to Git and aren't
>> interested in pushing Git commits back to Subversion, you can use this
>> option to store timestamps of fetched commits as though they were made
>> in the local timezone of the host on which git svn is run.  This makes
>> the times and timezones of a resulting "git log" agree with what "svn
>> log" shows for the same repository.
>>
>> Signed-off-by: Pete Harlan <pgit@pcharlan.com>
>> ---
>>
>> This is a patch I've had floating around for a while.  I haven't
>> submitted it before because I find the solution ungainly.  There has
>> to be a better way to convert from one timezone to the other, but I
>> didn't run across it and now that I've converted away from Subversion
>> I'm sort of done thinking about it.  I'm submitting it now because
>> even in its current state it would have saved me some headache.
>>
>> Also, I'm not sure I'm correct when asserting that converting
>> timezones like this will break Subversion interoperability.  Eric, if
>> that isn't true then I can remove that claim and resubmit.  If
>> converting timezones breaks nothing, then maybe it could even be the
>> default.
> 
> Hi,
> 
> It'll break interoperability between multiple users of git-svn
> tracking the same repo.  But several options already allow for
> this (authors file, noMetdata, ...), so I'm fine with it as long
> as it's optional.

Thank you for your review.  I'll comment here and then followup with a
replacement patch.

>> One improvement that I didn't bother to make would be to convert to
>> different local timezones based on author.  This change uses the
>> timezone of the machine running git-svn, which in my case was fine.
>> Using per-author timezones would be nice, but since parse_svn_date()
>> doesn't already know which author the date is associated with it would
>> be a more intrusive change.
> 
> Could be an interesting idea, but on the other hand I doubt many people
> would bother configuring the authors-file for it.
> 
> On a side note, for the total conversions I've done, I've found it
> easier/faster/more bandwidth efficient to just forgo authors-file
> entirely and use git-filter-branch after-the-fact.

Interesting.  When I was using git-svn I was new enough to Git that I
wasn't aware of filter-branch.

>> My primary motivation in this was to reduce transition shock among our
>> development team.  The fewer ways "git log" looks unhelpfully
>> different than the old "svn log" the better; converting all commit
>> times into GMT wasn't going to look friendly.
>>
>> Comments welcome.
> 
> My usual coding style nits apply (pretty much git (and Linux kernel)
> standard coding style things, too).
> 
> No space between "function(arguments)".
> 
> lower_snake_case, especially for local variables.  mixedCase requires
> more effort to read IMO.

Thanks; I'm sorry you had to point these things out.  Hopefully fixed
in the followup patch.

> More comments inline...
> 
>> --Pete
>>
>>  Documentation/git-svn.txt              |    8 ++++
>>  contrib/completion/git-completion.bash |    2 +-
>>  git-svn.perl                           |   56 ++++++++++++++++++++++++++++++-
>>  3 files changed, 63 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
>> index 8d0c421..8811bf0 100644
>> --- a/Documentation/git-svn.txt
>> +++ b/Documentation/git-svn.txt
>> @@ -92,6 +92,14 @@ COMMANDS
>>  	.git/config file may be specified as an optional command-line
>>  	argument.
>>
>> +--convert-timezones;;
> 
> Is it "timezone" or "timezones" here?  I think "convert-timezone" is
> more correct since we only use the local timezone, not different
> ones for each author.  On the other hand, maybe "--localtime" is
> an even better name for this option...
> 
> Any other opinions out there?

I liked your "--localtime" suggestion, and used that in v2.  I
originally chose plural for "timzeones" because it converts between
two timezones, and there are two timestamps associated with each
commit (even if they're the same, in git-svn).  But singular would
have made just as much sense, and at one point it was singular.

>> +	Store Git commit times in the local timezone instead of UTC.  This
>> +	makes 'git-log' (even without --date=local) show the same times
>> +	that `svn log` would in the local timezone.
>> +
>> +This breaks interoperability with SVN, but may be cosmetically
>> +desirable when converting a repository from SVN to Git.
> 
> Again, this only breaks interoperability with other users of git-svn
> using the default configuration on the same repo.

Thanks, fixed in v2.

>>  'clone'::
>>  	Runs 'init' and 'fetch'.  It will automatically create a
>>  	directory based on the basename of the URL passed to it;
>> diff --git a/git-svn.perl b/git-svn.perl
>> index ad01e18..c2f600d 100755
>> --- a/git-svn.perl
>> +++ b/git-svn.perl
>> @@ -66,7 +66,7 @@ my ($_stdin, $_help, $_edit,
>>  	$_version, $_fetch_all, $_no_rebase,
>>  	$_merge, $_strategy, $_dry_run, $_local,
>>  	$_prefix, $_no_checkout, $_url, $_verbose,
>> -	$_git_format, $_commit_url, $_tag);
>> +	$_git_format, $_commit_url, $_tag, $_convert_timezones);
> 
> Not easy to tell (and apologies for that) but this new variable probably
> belongs in the Git::SVN namespace.  I really need to find some time to
> reorganize and split out the source to git-svn.

I moved it into Git::SVN for v2, though I admit to not having a good
grasp of the big picture about what belongs where.

>>  $Git::SVN::_follow_parent = 1;
>>  my %remote_opts = ( 'username=s' => \$Git::SVN::Prompt::_username,
>>                      'config-dir=s' => \$Git::SVN::Ra::config_dir,
>> @@ -84,6 +84,7 @@ my %fc_opts = ( 'follow-parent|follow!' => \$Git::SVN::_follow_parent,
>>  		   \$Git::SVN::_repack_flags,
>>  		'use-log-author' => \$Git::SVN::_use_log_author,
>>  		'add-author-from' => \$Git::SVN::_add_author_from,
>> +		'convert-timezones' => \$_convert_timezones,
>>  		%remote_opts );
>>
>>  my ($_trunk, $_tags, $_branches, $_stdlayout);
>> @@ -2526,12 +2527,63 @@ sub get_untracked {
>>  	\@out;
>>  }
>>
>> +# parse_svn_date(DATE)
>> +# --------------------
>> +# Given a date (in UTC) from Subversion, return a string in the format
>> +# "<TZ Offset> <local date/time>" that Git will use.
>> +#
>> +# By default the parsed date will be in UTC for interoperating with
>> +# Subversion, but if $_convert_timezones is true we'll convert it to
>> +# the local timezone instead.
>>  sub parse_svn_date {
>>  	my $date = shift || return '+0000 1970-01-01 00:00:00';
>>  	my ($Y,$m,$d,$H,$M,$S) = ($date =~ /^(\d{4})\-(\d\d)\-(\d\d)T
>>  	                                    (\d\d)\:(\d\d)\:(\d\d).\d+Z$/x) or
>>  	                                 croak "Unable to parse date: $date\n";
>> -	"+0000 $Y-$m-$d $H:$M:$S";
>> +	my $parsed_date;    # Set next.
>> +
>> +	if ($_convert_timezones) {
>> +		# Translate the Subversion datetime to an epoch time.
>> +		# We need to switch ourselves to $date's timezone,
>> +		# UTC, for this.
>> +		my $oldEnvTZ = $ENV{TZ};
>> +		$ENV{TZ} = 'UTC';
>> +
>> +		my $epochUTC =
>> +		    POSIX::strftime ('%s', $S, $M, $H, $d, $m - 1, $Y - 1900);
>> +
>> +		# Determine our local timezone (including DST) at the
>> +		# time of $epochUTC.  $Git::SVN::Log::TZ stored the
>> +		# value of TZ, if any, at the time we were run.
>> +		if (defined $Git::SVN::Log::TZ) {
>> +			$ENV{TZ} = $Git::SVN::Log::TZ;
>> +		} else {
>> +			delete $ENV{TZ};
>> +		}
>> +
>> +		my $ourTZ =
>> +		    POSIX::strftime ('%Z', $S, $M, $H, $d, $m - 1, $Y - 1900);
>> +
>> +		# This converts $epochUTC into our local timezone.
>> +		my ($sec, $min, $hour, $mday, $mon, $year,
>> +		    $wday, $yday, $isdst) = localtime ($epochUTC);
>> +
>> +		$parsed_date = sprintf ('%s %04d-%02d-%02d %02d:%02d:%02d',
>> +					$ourTZ, $year + 1900, $mon + 1,
>> +					$mday, $hour, $min, $sec);
> 
> There's probably a reason you didn't use strftime here, or is there?

If you mean why couldn't I have saved an sprintf by using the previous
strftime call to format this data at the same time I got the timzeone,
it's because strftime doesn't convert the time into the local
timezone.  It just passes back the same values that you pass in.

> The stock Perl time/date handling functions have always frightened me,
> so I'll just trust the (+|-) (1|1900) things are correct :)

:) I tested it pretty well...

--
Pete Harlan
pgit@pcharlan.com

[PATCH v2] git-svn: Add --localtime option to "fetch"

[Pete Harlan]

By default git-svn stores timestamps of fetched commits in
Subversion's UTC format.  Passing --localtime to fetch will convert
them to the timezone of the server on which git-svn is run.

This makes the timestamps of a resulting "git log" agree with what
"svn log" shows for the same repository.

Signed-off-by: Pete Harlan <pgit@pcharlan.com>
---

Changes to v2 after feedback from Eric Wong:

1. "--convert-timezones" renamed to "--localtime".

2. Removed warnings about breaking interoperability with Subversion,
   because the option doesn't do that.  Instead warn about
   interoperability with other git-svn users cloning from the same
   repository if they don't all use or not use --localtime.

3. Move config variable into Git::SVN namespace.

4. Better conformance to coding guidelines.

 Documentation/git-svn.txt              |   11 ++++++
 contrib/completion/git-completion.bash |    2 +-
 git-svn.perl                           |   54 ++++++++++++++++++++++++++++++-
 3 files changed, 64 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index 8d0c421..63d2f5e 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -92,6 +92,17 @@ COMMANDS
 	.git/config file may be specified as an optional command-line
 	argument.

+--localtime;;
+	Store Git commit times in the local timezone instead of UTC.  This
+	makes 'git-log' (even without --date=local) show the same times
+	that `svn log` would in the local timezone.
+
+This doesn't interfere with interoperating with the Subversion
+repository you cloned from, but if you wish for your local Git
+repository to be able to interoperate with someone else's local Git
+repository, either don't use this option or you should both use it in
+the same local timezone.
+
 'clone'::
 	Runs 'init' and 'fetch'.  It will automatically create a
 	directory based on the basename of the URL passed to it;
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index f8b845a..c9d2c02 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1575,7 +1575,7 @@ _git_svn ()
 			--follow-parent --authors-file= --repack=
 			--no-metadata --use-svm-props --use-svnsync-props
 			--log-window-size= --no-checkout --quiet
-			--repack-flags --user-log-author $remote_opts
+			--repack-flags --user-log-author --localtime $remote_opts
 			"
 		local init_opts="
 			--template= --shared= --trunk= --tags=
diff --git a/git-svn.perl b/git-svn.perl
index ad01e18..0adc8db 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -84,6 +84,7 @@ my %fc_opts = ( 'follow-parent|follow!' => \$Git::SVN::_follow_parent,
 		   \$Git::SVN::_repack_flags,
 		'use-log-author' => \$Git::SVN::_use_log_author,
 		'add-author-from' => \$Git::SVN::_add_author_from,
+		'localtime' => \$Git::SVN::_localtime,
 		%remote_opts );

 my ($_trunk, $_tags, $_branches, $_stdlayout);
@@ -1364,7 +1365,7 @@ use constant rev_map_fmt => 'NH40';
 use vars qw/$default_repo_id $default_ref_id $_no_metadata $_follow_parent
             $_repack $_repack_flags $_use_svm_props $_head
             $_use_svnsync_props $no_reuse_existing $_minimize_url
-	    $_use_log_author $_add_author_from/;
+	    $_use_log_author $_add_author_from $_localtime/;
 use Carp qw/croak/;
 use File::Path qw/mkpath/;
 use File::Copy qw/copy/;
@@ -2526,12 +2527,61 @@ sub get_untracked {
 	\@out;
 }

+# parse_svn_date(DATE)
+# --------------------
+# Given a date (in UTC) from Subversion, return a string in the format
+# "<TZ Offset> <local date/time>" that Git will use.
+#
+# By default the parsed date will be in UTC; if $Git::SVN::_localtime
+# is true we'll convert it to the local timezone instead.
 sub parse_svn_date {
 	my $date = shift || return '+0000 1970-01-01 00:00:00';
 	my ($Y,$m,$d,$H,$M,$S) = ($date =~ /^(\d{4})\-(\d\d)\-(\d\d)T
 	                                    (\d\d)\:(\d\d)\:(\d\d).\d+Z$/x) or
 	                                 croak "Unable to parse date: $date\n";
-	"+0000 $Y-$m-$d $H:$M:$S";
+	my $parsed_date;    # Set next.
+
+	if ($Git::SVN::_localtime) {
+		# Translate the Subversion datetime to an epoch time.
+		# Begin by switching ourselves to $date's timezone, UTC.
+		my $old_env_TZ = $ENV{TZ};
+		$ENV{TZ} = 'UTC';
+
+		my $epoch_in_UTC =
+		    POSIX::strftime('%s', $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
+		# value of TZ, if any, at the time we were run.
+		if (defined $Git::SVN::Log::TZ) {
+			$ENV{TZ} = $Git::SVN::Log::TZ;
+		} else {
+			delete $ENV{TZ};
+		}
+
+		my $our_TZ =
+		    POSIX::strftime('%Z', $S, $M, $H, $d, $m - 1, $Y - 1900);
+
+		# This converts $epoch_in_UTC into our local timezone.
+		my ($sec, $min, $hour, $mday, $mon, $year,
+		    $wday, $yday, $isdst) = localtime($epoch_in_UTC);
+
+		$parsed_date = sprintf('%s %04d-%02d-%02d %02d:%02d:%02d',
+				       $our_TZ, $year + 1900, $mon + 1,
+				       $mday, $hour, $min, $sec);
+
+		# Reset us to the timezone in effect when we entered
+		# this routine.
+		if (defined $old_env_TZ) {
+			$ENV{TZ} = $old_env_TZ;
+		} else {
+			delete $ENV{TZ};
+		}
+	} else {
+		$parsed_date = "+0000 $Y-$m-$d $H:$M:$S";
+	}
+
+	return $parsed_date;
 }

 sub check_author {
-- 
1.6.1.77.g953e7

Re: [PATCH v2] git-svn: Add --localtime option to "fetch"

[Eric Wong]

Pete Harlan <pgit@pcharlan.com> wrote:
> By default git-svn stores timestamps of fetched commits in
> Subversion's UTC format.  Passing --localtime to fetch will convert
> them to the timezone of the server on which git-svn is run.
> 
> This makes the timestamps of a resulting "git log" agree with what
> "svn log" shows for the same repository.
> 
> Signed-off-by: Pete Harlan <pgit@pcharlan.com>

Thanks Peter,

Acked-by: Eric Wong <normalperson@yhbt.net>

> ---
> 
> Changes to v2 after feedback from Eric Wong:
> 
> 1. "--convert-timezones" renamed to "--localtime".
> 
> 2. Removed warnings about breaking interoperability with Subversion,
>    because the option doesn't do that.  Instead warn about
>    interoperability with other git-svn users cloning from the same
>    repository if they don't all use or not use --localtime.
> 
> 3. Move config variable into Git::SVN namespace.
> 
> 4. Better conformance to coding guidelines.
> 
>  Documentation/git-svn.txt              |   11 ++++++
>  contrib/completion/git-completion.bash |    2 +-
>  git-svn.perl                           |   54 ++++++++++++++++++++++++++++++-
>  3 files changed, 64 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
> index 8d0c421..63d2f5e 100644
> --- a/Documentation/git-svn.txt
> +++ b/Documentation/git-svn.txt
> @@ -92,6 +92,17 @@ COMMANDS
>  	.git/config file may be specified as an optional command-line
>  	argument.
> 
> +--localtime;;
> +	Store Git commit times in the local timezone instead of UTC.  This
> +	makes 'git-log' (even without --date=local) show the same times
> +	that `svn log` would in the local timezone.
> +
> +This doesn't interfere with interoperating with the Subversion
> +repository you cloned from, but if you wish for your local Git
> +repository to be able to interoperate with someone else's local Git
> +repository, either don't use this option or you should both use it in
> +the same local timezone.
> +
>  'clone'::
>  	Runs 'init' and 'fetch'.  It will automatically create a
>  	directory based on the basename of the URL passed to it;
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index f8b845a..c9d2c02 100755
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -1575,7 +1575,7 @@ _git_svn ()
>  			--follow-parent --authors-file= --repack=
>  			--no-metadata --use-svm-props --use-svnsync-props
>  			--log-window-size= --no-checkout --quiet
> -			--repack-flags --user-log-author $remote_opts
> +			--repack-flags --user-log-author --localtime $remote_opts
>  			"
>  		local init_opts="
>  			--template= --shared= --trunk= --tags=
> diff --git a/git-svn.perl b/git-svn.perl
> index ad01e18..0adc8db 100755
> --- a/git-svn.perl
> +++ b/git-svn.perl
> @@ -84,6 +84,7 @@ my %fc_opts = ( 'follow-parent|follow!' => \$Git::SVN::_follow_parent,
>  		   \$Git::SVN::_repack_flags,
>  		'use-log-author' => \$Git::SVN::_use_log_author,
>  		'add-author-from' => \$Git::SVN::_add_author_from,
> +		'localtime' => \$Git::SVN::_localtime,
>  		%remote_opts );
> 
>  my ($_trunk, $_tags, $_branches, $_stdlayout);
> @@ -1364,7 +1365,7 @@ use constant rev_map_fmt => 'NH40';
>  use vars qw/$default_repo_id $default_ref_id $_no_metadata $_follow_parent
>              $_repack $_repack_flags $_use_svm_props $_head
>              $_use_svnsync_props $no_reuse_existing $_minimize_url
> -	    $_use_log_author $_add_author_from/;
> +	    $_use_log_author $_add_author_from $_localtime/;
>  use Carp qw/croak/;
>  use File::Path qw/mkpath/;
>  use File::Copy qw/copy/;
> @@ -2526,12 +2527,61 @@ sub get_untracked {
>  	\@out;
>  }
> 
> +# parse_svn_date(DATE)
> +# --------------------
> +# Given a date (in UTC) from Subversion, return a string in the format
> +# "<TZ Offset> <local date/time>" that Git will use.
> +#
> +# By default the parsed date will be in UTC; if $Git::SVN::_localtime
> +# is true we'll convert it to the local timezone instead.
>  sub parse_svn_date {
>  	my $date = shift || return '+0000 1970-01-01 00:00:00';
>  	my ($Y,$m,$d,$H,$M,$S) = ($date =~ /^(\d{4})\-(\d\d)\-(\d\d)T
>  	                                    (\d\d)\:(\d\d)\:(\d\d).\d+Z$/x) or
>  	                                 croak "Unable to parse date: $date\n";
> -	"+0000 $Y-$m-$d $H:$M:$S";
> +	my $parsed_date;    # Set next.
> +
> +	if ($Git::SVN::_localtime) {
> +		# Translate the Subversion datetime to an epoch time.
> +		# Begin by switching ourselves to $date's timezone, UTC.
> +		my $old_env_TZ = $ENV{TZ};
> +		$ENV{TZ} = 'UTC';
> +
> +		my $epoch_in_UTC =
> +		    POSIX::strftime('%s', $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
> +		# value of TZ, if any, at the time we were run.
> +		if (defined $Git::SVN::Log::TZ) {
> +			$ENV{TZ} = $Git::SVN::Log::TZ;
> +		} else {
> +			delete $ENV{TZ};
> +		}
> +
> +		my $our_TZ =
> +		    POSIX::strftime('%Z', $S, $M, $H, $d, $m - 1, $Y - 1900);
> +
> +		# This converts $epoch_in_UTC into our local timezone.
> +		my ($sec, $min, $hour, $mday, $mon, $year,
> +		    $wday, $yday, $isdst) = localtime($epoch_in_UTC);
> +
> +		$parsed_date = sprintf('%s %04d-%02d-%02d %02d:%02d:%02d',
> +				       $our_TZ, $year + 1900, $mon + 1,
> +				       $mday, $hour, $min, $sec);
> +
> +		# Reset us to the timezone in effect when we entered
> +		# this routine.
> +		if (defined $old_env_TZ) {
> +			$ENV{TZ} = $old_env_TZ;
> +		} else {
> +			delete $ENV{TZ};
> +		}
> +	} else {
> +		$parsed_date = "+0000 $Y-$m-$d $H:$M:$S";
> +	}
> +
> +	return $parsed_date;
>  }
> 
>  sub check_author {
> -- 
> 1.6.1.77.g953e7

Re: [PATCH v2] git-svn: Add --localtime option to "fetch"

[Junio C Hamano]

Thanks, both.