[PATCH 5/6 (v2)] upload-pack: send the HEAD information

[Junio C Hamano <gitster@pobox.com>]

This implements the server side of protocol extension to show which branch
the HEAD points at.  The information is sent after the terminating NUL
that comes after the server capabilities list, to cause older clients to
ignore it, while allowing newer clients to make use of that information

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 upload-pack.c |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/upload-pack.c b/upload-pack.c
index e5adbc0..4aa444a 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -579,9 +579,17 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 	if (!o)
 		die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 
-	if (capabilities)
-		packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
-			0, capabilities);
+	if (capabilities) {
+		unsigned char dummy[20];
+		const char *target = resolve_ref("HEAD", dummy, 0, NULL);
+
+		if (!target)
+			packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
+				     0, capabilities);
+		else
+			packet_write(1, "%s %s%c%s%c%s\n", sha1_to_hex(sha1), refname,
+				     0, capabilities, 0, target);
+	}
 	else
 		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 	capabilities = NULL;
-- 
1.6.0.4.864.g0f47a