Re: [RFC/PATCH] rebase: add -x option to record original commit name

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 6, 2010, 02:57 UTC
Message-ID: <7vtytvf4vp.fsf@alter.siamese.dyndns.org>
In-Reply-To: <76718491002051758s577d8b5eq2323cd66d479662@mail.gmail.com>

Jay Soffian <jaysoffian@gmail.com> writes:

Show 7 quoted lines

>> We might instead want to add a hook that is called from cherry-pick (and
>> rebase will get a similar one) immediately after the command creates a new
>> commit out of another commit, so that people can record the correspondence
>> in notes namespace if they choose to.
>
> Hmfph. So I know some folks don't like polluting log messages (e.g.,
> the git-svn-id footer, or apparently, the cherry-pick -x message),...

That reminds me of a slightly related topic. I've been running git-svn to follow (but never build) a project without metadata, exactly because I do not want the log message contamination. I am having a hard time mapping the commit object name back to the upstream subversion serial number.

I ended up using this hacky script for that. It finds the svn uuid from the metadata file, and then finds ".rev_map.$uuid" files from all over the place to see if any of them contains a record that points at the git commit I am interested in.

I really wish "git svn" has a built-in way to do something like that; perhaps I didn't look hard enough.

-- >8 --

#!/usr/bin/perl -w

use strict; use Carp qw/croak/; use Fcntl qw/:DEFAULT :seek/; use constant rev_map_fmt => 'NH40'; use File::Find;

my $uuid = `git config -f .git/svn/.metadata svn-remote.svn.uuid`; chomp($uuid);

# remotes/trunk

sub find_version {
	my ($name, $sha1) = @_;
	my ($fh, $size);
	if (!sysopen($fh, "$name/.rev_map.$uuid", O_RDONLY)) {
		return undef;
	}
	if (!binmode $fh) {
		close($fh);
		return undef;
	}
	$size = (stat($fh))[7];
	if (($size % 24) != 0) {
		close($fh);
		return undef;
	}

	while (sysread($fh, my $buf, 24) == 24) {
		my ($rev, $commit) = unpack(rev_map_fmt, $buf);
		if ($sha1 eq $commit) {
			close($fh);
			return $rev;
		}
	}
	close($fh);
	return undef;
}

my $top = ".git/svn/refs"; my $commit = $ARGV[0] || "HEAD"; my $sha1 = `git rev-parse $commit`; chomp($sha1); my $found;

sub match_svn_revision {
	if (-f "$_/.rev_map.$uuid") {
		my $it = "$File::Find::dir/$_";
		$it =~ s|^\Q$top\E/||;
		my $v = find_version($_, $sha1);
		if ($v) {
			$found = [$it, $v];
		}
		$File::Find::prune = 1;
	}
	if ($found) {
		$File::Find::prune = 1;
	}
}

File::Find::find(\&match_svn_revision, $top);

if ($found) {
	my ($origin, $rev) = @$found;
	$origin =~ s|^remotes/||;
	$origin =~ s|/|-|g;
	if ($origin eq 'trunk') {
		$origin = '';
	} else {
		$origin = "-$origin";
	}
	print "$rev$origin\n";
}