Merge branch 'mh/ref-clone-without-extra-refs'

* mh/ref-clone-without-extra-refs:
  write_remote_refs(): create packed (rather than extra) refs
  add_packed_ref(): new function in the refs API.
  ref_array: keep track of whether references are sorted
  pack_refs(): remove redundant check

diff --combined builtin/clone.c
index 9dcc5fe775dc8dd38bb905869ee87a9dc685dfcf,9413537a8e0f67b5d2e21cf133088f470cb26cb3..9084febb1428a4232b43d97912c7e3e7dfb9e382
--- 1/builtin/clone.c
--- 2/builtin/clone.c
+++ b/builtin/clone.c
@@@ -37,7 -37,7 +37,7 @@@ static const char * const builtin_clone
        NULL
  };
  
 -static int option_no_checkout, option_bare, option_mirror;
 +static int option_no_checkout, option_bare, option_mirror, option_single_branch = -1;
  static int option_local, option_no_hardlinks, option_shared, option_recursive;
  static char *option_template, *option_depth;
  static char *option_origin = NULL;
@@@ -48,7 -48,6 +48,7 @@@ static int option_verbosity
  static int option_progress;
  static struct string_list option_config;
  static struct string_list option_reference;
 +static const char *src_ref_prefix = "refs/heads/";
  
  static int opt_parse_reference(const struct option *opt, const char *arg, int unset)
  {
@@@ -93,8 -92,6 +93,8 @@@ static struct option builtin_clone_opti
                   "path to git-upload-pack on the remote"),
        OPT_STRING(0, "depth", &option_depth, "depth",
                    "create a shallow clone of that depth"),
 +      OPT_BOOL(0, "single-branch", &option_single_branch,
 +                  "clone only one branch, HEAD or --branch"),
        OPT_STRING(0, "separate-git-dir", &real_git_dir, "gitdir",
                   "separate git dir from working tree"),
        OPT_STRING_LIST('c', "config", &option_config, "key=value",
@@@ -430,28 -427,8 +430,28 @@@ static struct ref *wanted_peer_refs(con
        struct ref *local_refs = head;
        struct ref **tail = head ? &head->next : &local_refs;
  
 -      get_fetch_map(refs, refspec, &tail, 0);
 -      if (!option_mirror)
 +      if (option_single_branch) {
 +              struct ref *remote_head = NULL;
 +
 +              if (!option_branch)
 +                      remote_head = guess_remote_head(head, refs, 0);
 +              else {
 +                      struct strbuf sb = STRBUF_INIT;
 +                      strbuf_addstr(&sb, src_ref_prefix);
 +                      strbuf_addstr(&sb, option_branch);
 +                      remote_head = find_ref_by_name(refs, sb.buf);
 +                      strbuf_release(&sb);
 +              }
 +
 +              if (!remote_head && option_branch)
 +                      warning(_("Could not find remote branch %s to clone."),
 +                              option_branch);
 +              else
 +                      get_fetch_map(remote_head, refspec, &tail, 0);
 +      } else
 +              get_fetch_map(refs, refspec, &tail, 0);
 +
 +      if (!option_mirror && !option_single_branch)
                get_fetch_map(refs, tag_refspec, &tail, 0);
  
        return local_refs;
@@@ -464,28 -441,12 +464,27 @@@ static void write_remote_refs(const str
        for (r = local_refs; r; r = r->next) {
                if (!r->peer_ref)
                        continue;
-               add_extra_ref(r->peer_ref->name, r->old_sha1, 0);
+               add_packed_ref(r->peer_ref->name, r->old_sha1);
        }
  
        pack_refs(PACK_REFS_ALL);
-       clear_extra_refs();
  }
  
 +static void write_followtags(const struct ref *refs, const char *msg)
 +{
 +      const struct ref *ref;
 +      for (ref = refs; ref; ref = ref->next) {
 +              if (prefixcmp(ref->name, "refs/tags/"))
 +                      continue;
 +              if (!suffixcmp(ref->name, "^{}"))
 +                      continue;
 +              if (!has_sha1_file(ref->old_sha1))
 +                      continue;
 +              update_ref(msg, ref->name, ref->old_sha1,
 +                         NULL, 0, DIE_ON_ERR);
 +      }
 +}
 +
  static int write_one_config(const char *key, const char *value, void *data)
  {
        return git_config_set_multivar(key, value ? value : "true", "^$", 0);
@@@ -516,6 -477,7 +515,6 @@@ int cmd_clone(int argc, const char **ar
        struct strbuf key = STRBUF_INIT, value = STRBUF_INIT;
        struct strbuf branch_top = STRBUF_INIT, reflog_msg = STRBUF_INIT;
        struct transport *transport = NULL;
 -      char *src_ref_prefix = "refs/heads/";
        int err = 0;
  
        struct refspec *refspec;
@@@ -535,9 -497,6 +534,9 @@@
                usage_msg_opt(_("You must specify a repository to clone."),
                        builtin_clone_usage, builtin_clone_options);
  
 +      if (option_single_branch == -1)
 +              option_single_branch = option_depth ? 1 : 0;
 +
        if (option_mirror)
                option_bare = 1;
  
@@@ -685,8 -644,6 +684,8 @@@
                if (option_depth)
                        transport_set_option(transport, TRANS_OPT_DEPTH,
                                             option_depth);
 +              if (option_single_branch)
 +                      transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");
  
                transport_set_verbosity(transport, option_verbosity, option_progress);
  
@@@ -705,8 -662,6 +704,8 @@@
                clear_extra_refs();
  
                write_remote_refs(mapped_refs);
 +              if (option_single_branch)
 +                      write_followtags(refs, reflog_msg.buf);
  
                remote_head = find_ref_by_name(refs, "HEAD");
                remote_head_points_at =