From 63911b5d576e7250c132d117c53e66aaf34b7f47 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Thu, 9 Feb 2017 00:16:47 +0000
Subject: [PATCH] git-debrebase: capture breakwater tip

---
 git-debrebase | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/git-debrebase b/git-debrebase
index 6542c65c..fbb97329 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -343,6 +343,7 @@ sub launder ($$$) {
 	mkdir $rd or $!==EEXIST or die $!;
 	my $current_method;
 	foreach my $cl (qw(Debian), (reverse @deb_cl),
+			{ SpecialMethod => 'RecordBreakwaterTip' },
 			qw(Upstream), (reverse @ups_cl)) {
 	    if (!ref $cl) {
 		$current_method = $cl;
@@ -358,6 +359,10 @@ sub launder ($$$) {
 	    } elsif ($method eq 'StartRewrite') {
 		$rewriting = 1;
 		next;
+	    } elsif ($method eq 'RecordBreakwaterTip') {
+		last if $wantdebonly;
+		$breakwater = $build;
+		next;
 	    } elsif ($method eq 'DgitImportDebianUpdate') {
 		$read_tree_debian->($cltree);
 		$rm_tree_cached(qw(debian/patches));
@@ -396,7 +401,7 @@ sub launder ($$$) {
 	map { $wantdebonly ? "$_:debian" : $_ },
 	$input, $build;
 
-    return $build;
+    return ($build, $breakwater);
 }
 
 sub get_head () { return git_rev_parse qw(HEAD); }
@@ -408,8 +413,9 @@ sub update_head ($$) {
 
 sub cmd_launder () {
     my $old = get_head();
-    my $got = launder $old, 0, undef, 0;
-    update_head $old, $new, 'launder'; # no tree changes!
+    my ($tip,$breakwater) = launder $old, 0, undef, 0;
+    update_head $old, $tip, 'launder'; # no tree changes!
+    printf "# breakwater tip:\n%s\n", $breakwater;
 }
 
 my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
-- 
2.30.2