git-svn: add fetch --parent option

Signed-off-by: Jason Merrill <jason@redhat.com>
Acked-By: Eric Wong <normalperson@yhbt.net>

Documentation/git-svn.txt

diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index b7b1af8..85b2c8d 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -97,6 +97,9 @@
 	makes 'git-log' (even without --date=local) show the same times
 	that `svn log` would in the local timezone.
 
+--parent;;
+	Fetch only from the SVN parent of the current HEAD.
+
 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

git-svn.perl

diff --git a/git-svn.perl b/git-svn.perl
index d919798..cb718b8 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -63,7 +63,7 @@
 my ($_stdin, $_help, $_edit,
 	$_message, $_file,
 	$_template, $_shared,
-	$_version, $_fetch_all, $_no_rebase,
+	$_version, $_fetch_all, $_no_rebase, $_fetch_parent,
 	$_merge, $_strategy, $_dry_run, $_local,
 	$_prefix, $_no_checkout, $_url, $_verbose,
 	$_git_format, $_commit_url, $_tag);
@@ -112,6 +112,7 @@
 	fetch => [ \&cmd_fetch, "Download new revisions from SVN",
 			{ 'revision|r=s' => \$_revision,
 			  'fetch-all|all' => \$_fetch_all,
+			  'parent|p' => \$_fetch_parent,
 			   %fc_opts } ],
 	clone => [ \&cmd_clone, "Initialize and fetch revisions",
 			{ 'revision|r=s' => \$_revision,
@@ -381,12 +382,21 @@
 	}
 	my ($remote) = @_;
 	if (@_ > 1) {
-		die "Usage: $0 fetch [--all] [svn-remote]\n";
+		die "Usage: $0 fetch [--all] [--parent] [svn-remote]\n";
 	}
-	$remote ||= $Git::SVN::default_repo_id;
-	if ($_fetch_all) {
+	if ($_fetch_parent) {
+		my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
+		unless ($gs) {
+			die "Unable to determine upstream SVN information from ",
+			    "working tree history\n";
+		}
+	        # just fetch, don't checkout.
+		$_no_checkout = 'true';
+		$_fetch_all ? $gs->fetch_all : $gs->fetch;
+	} elsif ($_fetch_all) {
 		cmd_multi_fetch();
 	} else {
+		$remote ||= $Git::SVN::default_repo_id;
 		Git::SVN::fetch_all($remote, Git::SVN::read_all_remotes());
 	}
 }