contrib/git-svn: add -b/--branch switch for branch detection

[git.git] / contrib / git-svn / git-svn.perl

diff --git a/contrib/git-svn/git-svn.perl b/contrib/git-svn/git-svn.perl
index 0e092c5..1f9a470 100755 (executable)
--- a/contrib/git-svn/git-svn.perl
+++ b/contrib/git-svn/git-svn.perl
@@ -35,6 +35,7 @@ my $sha1 = qr/[a-f\d]{40}/;
 my $sha1_short = qr/[a-f\d]{6,40}/;
 my ($_revision,$_stdin,$_no_ignore_ext,$_no_stop_copy,$_help,$_rmdir,$_edit,
        $_find_copies_harder, $_l, $_version, $_upgrade);
+my (@_branch_from, %tree_map);
 
 GetOptions(    'revision|r=s' => \$_revision,
                'no-ignore-externals' => \$_no_ignore_ext,
@@ -43,6 +44,7 @@ GetOptions(   'revision|r=s' => \$_revision,
                'rmdir' => \$_rmdir,
                'upgrade' => \$_upgrade,
                'help|H|h' => \$_help,
+               'branch|b=s' => \@_branch_from,
                'find-copies-harder' => \$_find_copies_harder,
                'l=i' => \$_l,
                'version|V' => \$_version,
@@ -831,6 +833,8 @@ sub git_commit {
        my $uuid = $info->{'Repository UUID'};
        defined $uuid or croak "Unable to get Repository UUID\n";
 
+       map_tree_joins() if (@_branch_from && !%tree_map);
+
        # commit parents can be conditionally bound to a particular
        # svn revision via: "svn_revno=commit_sha1", filter them out here:
        my @exec_parents;
@@ -852,6 +856,17 @@ sub git_commit {
                git_addremove();
                chomp(my $tree = `git-write-tree`);
                croak if $?;
+               if (exists $tree_map{$tree}) {
+                       my %seen_parent = map { $_ => 1 } @exec_parents;
+                       foreach (@{$tree_map{$tree}}) {
+                               # MAXPARENT is defined to 16 in commit-tree.c:
+                               if ($seen_parent{$_} || @exec_parents > 16) {
+                                       next;
+                               }
+                               push @exec_parents, $_;
+                               $seen_parent{$_} = 1;
+                       }
+               }
                my $msg_fh = IO::File->new_tmpfile or croak $!;
                print $msg_fh $log_msg->{msg}, "\ngit-svn-id: ",
                                        "$SVN_URL\@$log_msg->{revision}",
@@ -975,6 +990,29 @@ sub check_upgrade_needed {
        }
 }
 
+# fills %tree_map with a reverse mapping of trees to commits.  Useful
+# for finding parents to commit on.
+sub map_tree_joins {
+       foreach my $br (@_branch_from) {
+               my $pid = open my $pipe, '-|';
+               defined $pid or croak $!;
+               if ($pid == 0) {
+                       exec(qw(git-rev-list --pretty=raw), $br) or croak $?;
+               }
+               while (<$pipe>) {
+                       if (/^commit ($sha1)$/o) {
+                               my $commit = $1;
+                               my ($tree) = (<$pipe> =~ /^tree ($sha1)$/o);
+                               unless (defined $tree) {
+                                       die "Failed to parse commit $commit\n";
+                               }
+                               push @{$tree_map{$tree}}, $commit;
+                       }
+               }
+               close $pipe or croak $?;
+       }
+}
+
 __END__
 
 Data structures: