Show peeled onion from upload-pack and server-info.

This updates git-ls-remote to show SHA1 names of objects that are
referred by tags, in the "ref^{}" notation.

This would make git-findtags (without -t flag) almost trivial.

    git-peek-remote . |
    sed -ne "s:^$target	"'refs/tags/\(.*\)^{}$:\1:p'

Also Pasky could do:

    git-ls-remote --tags $remote |
    sed -ne 's:\(	refs/tags/.*\)^{}$:\1:p'

to find out what object each of the remote tags refers to, and
if he has one locally, run "git-fetch $remote tag $tagname" to
automatically catch up with the upstream tags.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-fetch.sh

@@ -176,6 +176,7 @@ if test "$tags"
 then
 	taglist=$(git-ls-remote --tags "$remote" |
 		sed -e '
+			/\^{}$/d
 			s/^[^	]*	//
 			s/.*/&:&/')
 	if test "$#" -gt 1

server-info.c

@@ -9,7 +9,14 @@ static FILE *info_ref_fp;
 
 static int add_info_ref(const char *path, const unsigned char *sha1)
 {
+	struct object *o = parse_object(sha1);
+
 	fprintf(info_ref_fp, "%s	%s\n", sha1_to_hex(sha1), path);
+	if (o->type == tag_type) {
+		o = deref_tag(o);
+		fprintf(info_ref_fp, "%s	%s^{}\n",
+			sha1_to_hex(o->sha1), path);
+	}
 	return 0;
 }
 

upload-pack.c

@@ -1,6 +1,8 @@
 #include "cache.h"
 #include "refs.h"
 #include "pkt-line.h"
+#include "tag.h"
+#include "object.h"
 
 static const char upload_pack_usage[] = "git-upload-pack <dir>";
 
@@ -165,7 +167,13 @@ static int receive_needs(void)
 
 static int send_ref(const char *refname, const unsigned char *sha1)
 {
+	struct object *o = parse_object(sha1);
+
 	packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
+	if (o->type == tag_type) {
+		o = deref_tag(o);
+		packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
+	}
 	return 0;
 }