mirror pushing

index bb774d0..a3aa5ad 100644
@@ -574,10 +574,12 @@ static const struct refspec *check_pattern_match(const struct refspec *rs,
  * without thinking.
  */
 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
-	       int nr_refspec, char **refspec, int all)
+	       int nr_refspec, char **refspec, int flags)
 {
 	struct refspec *rs =
 		parse_ref_spec(nr_refspec, (const char **) refspec);
+	int send_all = flags & 01;
+	int send_mirror = flags & 02;
 
 	if (match_explicit_refs(src, dst, dst_tail, rs, nr_refspec))
 		return -1;

@@ -594,7 +596,7 @@ int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 			if (!pat)
 				continue;
 		}
-		else if (prefixcmp(src->name, "refs/heads/"))
+		else if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
 			/*
 			 * "matching refs"; traditionally we pushed everything
 			 * including refs outside refs/heads/ hierarchy, but

@@ -615,10 +617,13 @@ int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 		if (dst_peer && dst_peer->peer_ref)
 			/* We're already sending something to this ref. */
 			goto free_name;
-		if (!dst_peer && !nr_refspec && !all)
-			/* Remote doesn't have it, and we have no
+
+		if (!dst_peer && !nr_refspec && !(send_all || send_mirror))
+			/*
+			 * Remote doesn't have it, and we have no
 			 * explicit pattern, and we don't have
-			 * --all. */
+			 * --all nor --mirror.
+			 */
 			goto free_name;
 		if (!dst_peer) {
 			/* Create a new one and link it */

index 9fc8a81..39b4b17 100644
@@ -7,11 +7,12 @@
 #include "remote.h"
 
 static const char send_pack_usage[] =
-"git-send-pack [--all] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]\n"
+"git-send-pack [--all | --mirror] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]\n"
 "  --all and explicit <ref> specification are mutually exclusive.";
 static const char *receivepack = "git-receive-pack";
 static int verbose;
 static int send_all;
+static int send_mirror;
 static int force_update;
 static int use_thin_pack;
 

@@ -200,7 +201,7 @@ static int send_pack(int in, int out, struct remote *remote, int nr_refspec, cha
 	if (!remote_tail)
 		remote_tail = &remote_refs;
 	if (match_refs(local_refs, remote_refs, &remote_tail,
-		       nr_refspec, refspec, send_all))
+		       nr_refspec, refspec, (send_all | (send_mirror << 1))))
 		return -1;
 
 	if (!remote_refs) {

@@ -215,19 +216,24 @@ static int send_pack(int in, int out, struct remote *remote, int nr_refspec, cha
 	for (ref = remote_refs; ref; ref = ref->next) {
 		char old_hex[60], *new_hex;
 		int will_delete_ref;
+		const unsigned char *new_sha1;
 
-		if (!ref->peer_ref)
-			continue;
-
+		if (!ref->peer_ref) {
+			if (!send_mirror)
+				continue;
+			new_sha1 = null_sha1;
+		}
+		else
+			new_sha1 = ref->peer_ref->new_sha1;
 
-		will_delete_ref = is_null_sha1(ref->peer_ref->new_sha1);
+		will_delete_ref = is_null_sha1(new_sha1);
 		if (will_delete_ref && !allow_deleting_refs) {
 			error("remote does not support deleting refs");
 			ret = -2;
 			continue;
 		}
 		if (!will_delete_ref &&
-		    !hashcmp(ref->old_sha1, ref->peer_ref->new_sha1)) {
+		    !hashcmp(ref->old_sha1, new_sha1)) {
 			if (verbose)
 				fprintf(stderr, "'%s': up-to-date\n", ref->name);
 			continue;

@@ -257,8 +263,7 @@ static int send_pack(int in, int out, struct remote *remote, int nr_refspec, cha
 		    !is_null_sha1(ref->old_sha1) &&
 		    !ref->force) {
 			if (!has_sha1_file(ref->old_sha1) ||
-			    !ref_newer(ref->peer_ref->new_sha1,
-				       ref->old_sha1)) {
+			    !ref_newer(new_sha1, ref->old_sha1)) {
 				/* We do not have the remote ref, or
 				 * we know that the remote ref is not
 				 * an ancestor of what we are trying to

@@ -276,7 +281,7 @@ static int send_pack(int in, int out, struct remote *remote, int nr_refspec, cha
 				continue;
 			}
 		}
-		hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
+		hashcpy(ref->new_sha1, new_sha1);
 		if (!will_delete_ref)
 			new_refs++;
 		strcpy(old_hex, sha1_to_hex(ref->old_sha1));

@@ -396,6 +401,10 @@ int main(int argc, char **argv)
 				send_all = 1;
 				continue;
 			}
+			if (!strcmp(arg, "--mirror")) {
+				send_mirror = 1;
+				continue;
+			}
 			if (!strcmp(arg, "--force")) {
 				force_update = 1;
 				continue;

@@ -420,7 +429,11 @@ int main(int argc, char **argv)
 	}
 	if (!dest)
 		usage(send_pack_usage);
-	if (heads && send_all)
+	/*
+	 * --all and --mirror are incompatible; neither makes sense
+	 * with any refspecs.
+	 */
+	if ((heads && (send_all || send_mirror)) || (send_all && send_mirror))
 		usage(send_pack_usage);
 	verify_remote_names(nr_heads, heads);
 

index 4ee36c2..e421e96 100644
@@ -8,7 +8,7 @@
 #include "remote.h"
 #include "transport.h"
 
-static const char push_usage[] = "git-push [--all] [--tags] [--receive-pack=<git-receive-pack>] [--repo=all] [-f | --force] [-v] [<repository> <refspec>...]";
+static const char push_usage[] = "git-push [--all | --mirror] [--tags] [--receive-pack=<git-receive-pack>] [--repo=all] [-f | --force] [-v] [<repository> <refspec>...]";
 
 static int all, thin, verbose;
 static const char *receivepack;

@@ -85,6 +85,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 {
 	int i;
 	int flags = 0;
+	int modes_specified = 0;
 	const char *repo = NULL;	/* default repository */
 
 	for (i = 1; i < argc; i++) {

@@ -105,6 +106,12 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		}
 		if (!strcmp(arg, "--all")) {
 			flags |= TRANSPORT_PUSH_ALL;
+			modes_specified++;
+			continue;
+		}
+		if (!strcmp(arg, "--mirror")) {
+			flags |= TRANSPORT_PUSH_MIRROR;
+			modes_specified++;
 			continue;
 		}
 		if (!strcmp(arg, "--tags")) {

@@ -137,5 +144,10 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 	if (all && refspec)
 		usage(push_usage);
 
+	if (modes_specified > 1) {
+		error("--all and --mirror are incompatible");
+		usage(push_usage);
+	}
+
 	return do_push(repo, flags);
 }

index 7266fd3..e45f3c0 100644
@@ -281,6 +281,9 @@ static int rsync_transport_push(struct transport *transport,
 	struct child_process rsync;
 	const char *args[8];
 
+	if (flags & TRANSPORT_PUSH_MIRROR)
+		return error("rsync transport does not support mirror mode");
+
 	/* first push the objects */
 
 	strbuf_addstr(&buf, transport->url);

@@ -373,6 +376,9 @@ static int curl_transport_push(struct transport *transport, int refspec_nr, cons
 	int argc;
 	int err;
 
+	if (flags & TRANSPORT_PUSH_MIRROR)
+		return error("http transport does not support mirror mode");
+
 	argv = xmalloc((refspec_nr + 11) * sizeof(char *));
 	argv[0] = "http-push";
 	argc = 1;

@@ -667,6 +673,8 @@ static int git_transport_push(struct transport *transport, int refspec_nr, const
 		argv[argc++] = "--all";
 	if (flags & TRANSPORT_PUSH_FORCE)
 		argv[argc++] = "--force";
+	if (flags & TRANSPORT_PUSH_MIRROR)
+		argv[argc++] = "--mirror";
 	if (data->receivepack) {
 		char *rp = xmalloc(strlen(data->receivepack) + 16);
 		sprintf(rp, "--receive-pack=%s", data->receivepack);

index 6e318e4..8383774 100644
@@ -29,6 +29,7 @@ struct transport {
 
 #define TRANSPORT_PUSH_ALL 1
 #define TRANSPORT_PUSH_FORCE 2
+#define TRANSPORT_PUSH_MIRROR 4
 
 /* Returns a transport suitable for the url */
 struct transport *transport_get(struct remote *, const char *);