v3, 7 partsRemoving the guesswork of HEAD in "clone"

diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index 8f6e392..197d3f7 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -271,6 +271,7 @@ EOF
 test_expect_success 'set-head --auto fails w/multiple HEADs' '
 	(
 		cd test &&
+		git fetch two "refs/heads/*:refs/remotes/two/*" &&
 		test_must_fail git remote set-head --auto two >output 2>&1 &&
 		test_i18ncmp expect output
 	)

diff --git a/upload-pack.c b/upload-pack.c
index 127e59a..a6e107f 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -742,7 +742,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 	const char *refname_nons = strip_namespace(refname);
 	unsigned char peeled[20];
 
-	if (mark_our_ref(refname, sha1, flag, cb_data))
+	if (mark_our_ref(refname, sha1, flag, NULL))
 		return 0;
 
 	if (capabilities)

diff --git a/upload-pack.c b/upload-pack.c
index a6e107f..979fc8e 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -734,6 +734,16 @@ static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag
 	return 0;
 }
 
+static void format_symref_info(struct strbuf *buf, struct string_list *symref)
+{
+	struct string_list_item *item;
+
+	if (!symref->nr)
+		return;
+	for_each_string_list_item(item, symref)
+		strbuf_addf(buf, " symref=%s:%s", item->string, (char *)item->util);
+}
+
 static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
@@ -745,32 +755,60 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 	if (mark_our_ref(refname, sha1, flag, NULL))
 		return 0;
 
-	if (capabilities)
-		packet_write(1, "%s %s%c%s%s%s agent=%s\n",
+	if (capabilities) {
+		struct strbuf symref_info = STRBUF_INIT;
+
+		format_symref_info(&symref_info, cb_data);
+		packet_write(1, "%s %s%c%s%s%s%s agent=%s\n",
 			     sha1_to_hex(sha1), refname_nons,
 			     0, capabilities,
 			     allow_tip_sha1_in_want ? " allow-tip-sha1-in-want" : "",
 			     stateless_rpc ? " no-done" : "",
+			     symref_info.buf,
 			     git_user_agent_sanitized());
-	else
+		strbuf_release(&symref_info);
+	} else {
 		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
+	}
 	capabilities = NULL;
 	if (!peel_ref(refname, peeled))
 		packet_write(1, "%s %s^{}\n", sha1_to_hex(peeled), refname_nons);
 	return 0;
 }
 
+static int find_symref(const char *refname, const unsigned char *sha1, int flag,
+		       void *cb_data)
+{
+	const char *symref_target;
+	struct string_list_item *item;
+	unsigned char unused[20];
+
+	if ((flag & REF_ISSYMREF) == 0)
+		return 0;
+	symref_target = resolve_ref_unsafe(refname, unused, 0, &flag);
+	if (!symref_target || (flag & REF_ISSYMREF) == 0)
+		die("'%s' is a symref but it is not?", refname);
+	item = string_list_append(cb_data, refname);
+	item->util = xstrdup(symref_target);
+	return 0;
+}
+
 static void upload_pack(void)
 {
+	struct string_list symref = STRING_LIST_INIT_DUP;
+
+	head_ref_namespaced(find_symref, &symref);
+
 	if (advertise_refs || !stateless_rpc) {
 		reset_timeout();
-		head_ref_namespaced(send_ref, NULL);
-		for_each_namespaced_ref(send_ref, NULL);
+		head_ref_namespaced(send_ref, &symref);
+		for_each_namespaced_ref(send_ref, &symref);
 		packet_flush(1);
 	} else {
 		head_ref_namespaced(mark_our_ref, NULL);
 		for_each_namespaced_ref(mark_our_ref, NULL);
 	}
+	string_list_clear(&symref, 1);
 	if (advertise_refs)
 		return;
 

diff --git a/upload-pack.c b/upload-pack.c
index 979fc8e..2826909 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -798,6 +798,7 @@ static void upload_pack(void)
 	struct string_list symref = STRING_LIST_INIT_DUP;
 
 	head_ref_namespaced(find_symref, &symref);
+	for_each_namespaced_ref(find_symref, &symref);
 
 	if (advertise_refs || !stateless_rpc) {
 		reset_timeout();

cache.h, connect.c

diff --git a/cache.h b/cache.h
index 85b544f..2c853ba 100644
--- a/cache.h
+++ b/cache.h
@@ -1098,7 +1098,6 @@ extern struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 extern int server_supports(const char *feature);
 extern int parse_feature_request(const char *features, const char *feature);
 extern const char *server_feature_value(const char *feature, int *len_ret);
-extern const char *parse_feature_value(const char *feature_list, const char *feature, int *len_ret);
 
 extern struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path);
 
diff --git a/connect.c b/connect.c
index a0783d4..e4c7ae6 100644
--- a/connect.c
+++ b/connect.c
@@ -8,6 +8,7 @@
 #include "url.h"
 
 static char *server_capabilities;
+static const char *parse_feature_value(const char *, const char *, int *);
 
 static int check_ref(const char *name, int len, unsigned int flags)
 {
@@ -116,7 +117,7 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 	return list;
 }
 
-const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
+static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 {
 	int len;
 

connect.c, t/t5505-remote.sh

diff --git a/connect.c b/connect.c
index e4c7ae6..553a80c 100644
--- a/connect.c
+++ b/connect.c
@@ -6,6 +6,7 @@
 #include "run-command.h"
 #include "remote.h"
 #include "url.h"
+#include "string-list.h"
 
 static char *server_capabilities;
 static const char *parse_feature_value(const char *, const char *, int *);
@@ -60,6 +61,61 @@ static void die_initial_contact(int got_at_least_one_head)
 		    "and the repository exists.");
 }
 
+static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
+{
+	char *sym, *target;
+	struct string_list_item *item;
+
+	if (!len)
+		return; /* just "symref" */
+	/* e.g. "symref=HEAD:refs/heads/master" */
+	sym = xmalloc(len + 1);
+	memcpy(sym, val, len);
+	sym[len] = '\0';
+	target = strchr(sym, ':');
+	if (!target)
+		/* just "symref=something" */
+		goto reject;
+	*(target++) = '\0';
+	if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
+	    check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
+		/* "symref=bogus:pair */
+		goto reject;
+	item = string_list_append(symref, sym);
+	item->util = target;
+	return;
+reject:
+	free(sym);
+	return;
+}
+
+static void annotate_refs_with_symref_info(struct ref *ref)
+{
+	struct string_list symref = STRING_LIST_INIT_DUP;
+	const char *feature_list = server_capabilities;
+
+	while (feature_list) {
+		int len;
+		const char *val;
+
+		val = parse_feature_value(feature_list, "symref", &len);
+		if (!val)
+			break;
+		parse_one_symref_info(&symref, val, len);
+		feature_list = val + 1;
+	}
+	sort_string_list(&symref);
+
+	for (; ref; ref = ref->next) {
+		struct string_list_item *item;
+		item = string_list_lookup(&symref, ref->name);
+		if (!item)
+			continue;
+		ref->symref = xstrdup((char *)item->util);
+	}
+	string_list_clear(&symref, 0);
+}
+
 /*
  * Read all the refs from the other end
  */
@@ -67,6 +123,7 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 			      struct ref **list, unsigned int flags,
 			      struct extra_have_objects *extra_have)
 {
+	struct ref **orig_list = list;
 	int got_at_least_one_head = 0;
 
 	*list = NULL;
@@ -114,6 +171,9 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 		list = &ref->next;
 		got_at_least_one_head = 1;
 	}
+
+	annotate_refs_with_symref_info(*orig_list);
+
 	return list;
 }
 
diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index 197d3f7..ac79dd9 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -160,9 +160,7 @@ cat >test/expect <<EOF
 * remote two
   Fetch URL: ../two
   Push  URL: ../three
-  HEAD branch (remote HEAD is ambiguous, may be one of the following):
-    another
-    master
+  HEAD branch: master
   Local refs configured for 'git push':
     ahead  forces to master  (fast-forwardable)
     master pushes to another (up to date)
@@ -262,17 +260,12 @@ test_expect_success 'set-head --auto' '
 	)
 '
 
-cat >test/expect <<\EOF
-error: Multiple remote HEAD branches. Please choose one explicitly with:
-  git remote set-head two another
-  git remote set-head two master
-EOF
-
-test_expect_success 'set-head --auto fails w/multiple HEADs' '
+test_expect_success 'set-head --auto has no problem w/multiple HEADs' '
 	(
 		cd test &&
 		git fetch two "refs/heads/*:refs/remotes/two/*" &&
-		test_must_fail git remote set-head --auto two >output 2>&1 &&
+		git remote set-head --auto two >output 2>&1 &&
+		echo "two/HEAD set to master" >expect &&
 		test_i18ncmp expect output
 	)
 '

diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 0629149..ccda6df 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -285,4 +285,15 @@ test_expect_success NOT_MINGW,NOT_CYGWIN 'clone local path foo:bar' '
 	git clone "./foo:bar" foobar
 '
 
+test_expect_success 'clone from a repository with two identical branches' '
+
+	(
+		cd src &&
+		git checkout -b another master
+	) &&
+	git clone src target-11 &&
+	test "z$( cd target-11 && git symbolic-ref HEAD )" = zrefs/heads/another
+
+'
+
 test_done