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

@@ -97,6 +97,9 @@ COMMANDS
 	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

@@ -63,7 +63,7 @@ BEGIN
 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, $_tag);
@@ -112,6 +112,7 @@ BEGIN
 	fetch => [ \&cmd_fetch, "Download new revisions from SVN",
 			{ 'revision|r=s' => \$_revision,
 			  'fetch-all|all' => \$_fetch_all,
+			  'parent|p' => \$_fetch_parent,
 			   %fc_opts } ],
 	clone => [ \&cmd_clone, "Initialize and fetch revisions",
 			{ 'revision|r=s' => \$_revision,
@@ -381,12 +382,21 @@ sub cmd_fetch {
 	}
 	my ($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());
 	}
 }