builtin/clone.c

   1 /*
   2  * Builtin "git clone"
   3  *
   4  * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>,
   5  *               2008 Daniel Barkalow <barkalow@iabervon.org>
   6  * Based on git-commit.sh by Junio C Hamano and Linus Torvalds
   7  *
   8  * Clone a repository into a different directory that does not yet exist.
   9  */
  10
  11 #include "builtin.h"
  12 #include "parse-options.h"
  13 #include "fetch-pack.h"
  14 #include "refs.h"
  15 #include "tree.h"
  16 #include "tree-walk.h"
  17 #include "unpack-trees.h"
  18 #include "transport.h"
  19 #include "strbuf.h"
  20 #include "dir.h"
  21 #include "pack-refs.h"
  22 #include "sigchain.h"
  23 #include "branch.h"
  24 #include "remote.h"
  25 #include "run-command.h"
  26
  27 /*
  28  * Overall FIXMEs:
  29  *  - respect DB_ENVIRONMENT for .git/objects.
  30  *
  31  * Implementation notes:
  32  *  - dropping use-separate-remote and no-separate-remote compatibility
  33  *
  34  */
  35 static const char * const builtin_clone_usage[] = {
  36         "git clone [options] [--] <repo> [<dir>]",
  37         NULL
  38 };
  39
  40 static int option_no_checkout, option_bare, option_mirror;
  41 static int option_local, option_no_hardlinks, option_shared, option_recursive;
  42 static char *option_template, *option_depth;
  43 static char *option_origin = NULL;
  44 static char *option_branch = NULL;
  45 static const char *real_git_dir;
  46 static char *option_upload_pack = "git-upload-pack";
  47 static int option_verbosity;
  48 static int option_progress;
  49 static struct string_list option_config;
  50 static struct string_list option_reference;
  51
  52 static int opt_parse_reference(const struct option *opt, const char *arg, int unset)
  53 {
  54         struct string_list *option_reference = opt->value;
  55         if (!arg)
  56                 return -1;
  57         string_list_append(option_reference, arg);
  58         return 0;
  59 }
  60
  61 static struct option builtin_clone_options[] = {
  62         OPT__VERBOSITY(&option_verbosity),
  63         OPT_BOOLEAN(0, "progress", &option_progress,
  64                         "force progress reporting"),
  65         OPT_BOOLEAN('n', "no-checkout", &option_no_checkout,
  66                     "don't create a checkout"),
  67         OPT_BOOLEAN(0, "bare", &option_bare, "create a bare repository"),
  68         { OPTION_BOOLEAN, 0, "naked", &option_bare, NULL,
  69                 "create a bare repository",
  70                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
  71         OPT_BOOLEAN(0, "mirror", &option_mirror,
  72                     "create a mirror repository (implies bare)"),
  73         OPT_BOOLEAN('l', "local", &option_local,
  74                     "to clone from a local repository"),
  75         OPT_BOOLEAN(0, "no-hardlinks", &option_no_hardlinks,
  76                     "don't use local hardlinks, always copy"),
  77         OPT_BOOLEAN('s', "shared", &option_shared,
  78                     "setup as shared repository"),
  79         OPT_BOOLEAN(0, "recursive", &option_recursive,
  80                     "initialize submodules in the clone"),
  81         OPT_BOOLEAN(0, "recurse-submodules", &option_recursive,
  82                     "initialize submodules in the clone"),
  83         OPT_STRING(0, "template", &option_template, "template-directory",
  84                    "directory from which templates will be used"),
  85         OPT_CALLBACK(0 , "reference", &option_reference, "repo",
  86                      "reference repository", &opt_parse_reference),
  87         OPT_STRING('o', "origin", &option_origin, "name",
  88                    "use <name> instead of 'origin' to track upstream"),
  89         OPT_STRING('b', "branch", &option_branch, "branch",
  90                    "checkout <branch> instead of the remote's HEAD"),
  91         OPT_STRING('u', "upload-pack", &option_upload_pack, "path",
  92                    "path to git-upload-pack on the remote"),
  93         OPT_STRING(0, "depth", &option_depth, "depth",
  94                     "create a shallow clone of that depth"),
  95         OPT_STRING(0, "separate-git-dir", &real_git_dir, "gitdir",
  96                    "separate git dir from working tree"),
  97         OPT_STRING_LIST('c', "config", &option_config, "key=value",
  98                         "set config inside the new repository"),
  99         OPT_END()
 100 };
 101
 102 static const char *argv_submodule[] = {
 103         "submodule", "update", "--init", "--recursive", NULL
 104 };
 105
 106 static char *get_repo_path(const char *repo, int *is_bundle)
 107 {
 108         static char *suffix[] = { "/.git", ".git", "" };
 109         static char *bundle_suffix[] = { ".bundle", "" };
 110         struct stat st;
 111         int i;
 112
 113         for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 114                 const char *path;
 115                 path = mkpath("%s%s", repo, suffix[i]);
 116                 if (stat(path, &st))
 117                         continue;
 118                 if (S_ISDIR(st.st_mode)) {
 119                         *is_bundle = 0;
 120                         return xstrdup(absolute_path(path));
 121                 } else if (S_ISREG(st.st_mode) && st.st_size > 8) {
 122                         /* Is it a "gitfile"? */
 123                         char signature[8];
 124                         int len, fd = open(path, O_RDONLY);
 125                         if (fd < 0)
 126                                 continue;
 127                         len = read_in_full(fd, signature, 8);
 128                         close(fd);
 129                         if (len != 8 || strncmp(signature, "gitdir: ", 8))
 130                                 continue;
 131                         path = read_gitfile(path);
 132                         if (path) {
 133                                 *is_bundle = 0;
 134                                 return xstrdup(absolute_path(path));
 135                         }
 136                 }
 137         }
 138
 139         for (i = 0; i < ARRAY_SIZE(bundle_suffix); i++) {
 140                 const char *path;
 141                 path = mkpath("%s%s", repo, bundle_suffix[i]);
 142                 if (!stat(path, &st) && S_ISREG(st.st_mode)) {
 143                         *is_bundle = 1;
 144                         return xstrdup(absolute_path(path));
 145                 }
 146         }
 147
 148         return NULL;
 149 }
 150
 151 static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
 152 {
 153         const char *end = repo + strlen(repo), *start;
 154         char *dir;
 155
 156         /*
 157          * Strip trailing spaces, slashes and /.git
 158          */
 159         while (repo < end && (is_dir_sep(end[-1]) || isspace(end[-1])))
 160                 end--;
 161         if (end - repo > 5 && is_dir_sep(end[-5]) &&
 162             !strncmp(end - 4, ".git", 4)) {
 163                 end -= 5;
 164                 while (repo < end && is_dir_sep(end[-1]))
 165                         end--;
 166         }
 167
 168         /*
 169          * Find last component, but be prepared that repo could have
 170          * the form  "remote.example.com:foo.git", i.e. no slash
 171          * in the directory part.
 172          */
 173         start = end;
 174         while (repo < start && !is_dir_sep(start[-1]) && start[-1] != ':')
 175                 start--;
 176
 177         /*
 178          * Strip .{bundle,git}.
 179          */
 180         if (is_bundle) {
 181                 if (end - start > 7 && !strncmp(end - 7, ".bundle", 7))
 182                         end -= 7;
 183         } else {
 184                 if (end - start > 4 && !strncmp(end - 4, ".git", 4))
 185                         end -= 4;
 186         }
 187
 188         if (is_bare) {
 189                 struct strbuf result = STRBUF_INIT;
 190                 strbuf_addf(&result, "%.*s.git", (int)(end - start), start);
 191                 dir = strbuf_detach(&result, NULL);
 192         } else
 193                 dir = xstrndup(start, end - start);
 194         /*
 195          * Replace sequences of 'control' characters and whitespace
 196          * with one ascii space, remove leading and trailing spaces.
 197          */
 198         if (*dir) {
 199                 char *out = dir;
 200                 int prev_space = 1 /* strip leading whitespace */;
 201                 for (end = dir; *end; ++end) {
 202                         char ch = *end;
 203                         if ((unsigned char)ch < '\x20')
 204                                 ch = '\x20';
 205                         if (isspace(ch)) {
 206                                 if (prev_space)
 207                                         continue;
 208                                 prev_space = 1;
 209                         } else
 210                                 prev_space = 0;
 211                         *out++ = ch;
 212                 }
 213                 *out = '\0';
 214                 if (out > dir && prev_space)
 215                         out[-1] = '\0';
 216         }
 217         return dir;
 218 }
 219
 220 static void strip_trailing_slashes(char *dir)
 221 {
 222         char *end = dir + strlen(dir);
 223
 224         while (dir < end - 1 && is_dir_sep(end[-1]))
 225                 end--;
 226         *end = '\0';
 227 }
 228
 229 static int add_one_reference(struct string_list_item *item, void *cb_data)
 230 {
 231         char *ref_git;
 232         struct strbuf alternate = STRBUF_INIT;
 233         struct remote *remote;
 234         struct transport *transport;
 235         const struct ref *extra;
 236
 237         /* Beware: real_path() and mkpath() return static buffer */
 238         ref_git = xstrdup(real_path(item->string));
 239         if (is_directory(mkpath("%s/.git/objects", ref_git))) {
 240                 char *ref_git_git = xstrdup(mkpath("%s/.git", ref_git));
 241                 free(ref_git);
 242                 ref_git = ref_git_git;
 243         } else if (!is_directory(mkpath("%s/objects", ref_git)))
 244                 die(_("reference repository '%s' is not a local directory."),
 245                     item->string);
 246
 247         strbuf_addf(&alternate, "%s/objects", ref_git);
 248         add_to_alternates_file(alternate.buf);
 249         strbuf_release(&alternate);
 250
 251         remote = remote_get(ref_git);
 252         transport = transport_get(remote, ref_git);
 253         for (extra = transport_get_remote_refs(transport); extra;
 254              extra = extra->next)
 255                 add_extra_ref(extra->name, extra->old_sha1, 0);
 256
 257         transport_disconnect(transport);
 258         free(ref_git);
 259         return 0;
 260 }
 261
 262 static void setup_reference(void)
 263 {
 264         for_each_string_list(&option_reference, add_one_reference, NULL);
 265 }
 266
 267 static void copy_alternates(struct strbuf *src, struct strbuf *dst,
 268                             const char *src_repo)
 269 {
 270         /*
 271          * Read from the source objects/info/alternates file
 272          * and copy the entries to corresponding file in the
 273          * destination repository with add_to_alternates_file().
 274          * Both src and dst have "$path/objects/info/alternates".
 275          *
 276          * Instead of copying bit-for-bit from the original,
 277          * we need to append to existing one so that the already
 278          * created entry via "clone -s" is not lost, and also
 279          * to turn entries with paths relative to the original
 280          * absolute, so that they can be used in the new repository.
 281          */
 282         FILE *in = fopen(src->buf, "r");
 283         struct strbuf line = STRBUF_INIT;
 284
 285         while (strbuf_getline(&line, in, '\n') != EOF) {
 286                 char *abs_path, abs_buf[PATH_MAX];
 287                 if (!line.len || line.buf[0] == '#')
 288                         continue;
 289                 if (is_absolute_path(line.buf)) {
 290                         add_to_alternates_file(line.buf);
 291                         continue;
 292                 }
 293                 abs_path = mkpath("%s/objects/%s", src_repo, line.buf);
 294                 normalize_path_copy(abs_buf, abs_path);
 295                 add_to_alternates_file(abs_buf);
 296         }
 297         strbuf_release(&line);
 298         fclose(in);
 299 }
 300
 301 static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 302                                    const char *src_repo, int src_baselen)
 303 {
 304         struct dirent *de;
 305         struct stat buf;
 306         int src_len, dest_len;
 307         DIR *dir;
 308
 309         dir = opendir(src->buf);
 310         if (!dir)
 311                 die_errno(_("failed to open '%s'"), src->buf);
 312
 313         if (mkdir(dest->buf, 0777)) {
 314                 if (errno != EEXIST)
 315                         die_errno(_("failed to create directory '%s'"), dest->buf);
 316                 else if (stat(dest->buf, &buf))
 317                         die_errno(_("failed to stat '%s'"), dest->buf);
 318                 else if (!S_ISDIR(buf.st_mode))
 319                         die(_("%s exists and is not a directory"), dest->buf);
 320         }
 321
 322         strbuf_addch(src, '/');
 323         src_len = src->len;
 324         strbuf_addch(dest, '/');
 325         dest_len = dest->len;
 326
 327         while ((de = readdir(dir)) != NULL) {
 328                 strbuf_setlen(src, src_len);
 329                 strbuf_addstr(src, de->d_name);
 330                 strbuf_setlen(dest, dest_len);
 331                 strbuf_addstr(dest, de->d_name);
 332                 if (stat(src->buf, &buf)) {
 333                         warning (_("failed to stat %s\n"), src->buf);
 334                         continue;
 335                 }
 336                 if (S_ISDIR(buf.st_mode)) {
 337                         if (de->d_name[0] != '.')
 338                                 copy_or_link_directory(src, dest,
 339                                                        src_repo, src_baselen);
 340                         continue;
 341                 }
 342
 343                 /* Files that cannot be copied bit-for-bit... */
 344                 if (!strcmp(src->buf + src_baselen, "/info/alternates")) {
 345                         copy_alternates(src, dest, src_repo);
 346                         continue;
 347                 }
 348
 349                 if (unlink(dest->buf) && errno != ENOENT)
 350                         die_errno(_("failed to unlink '%s'"), dest->buf);
 351                 if (!option_no_hardlinks) {
 352                         if (!link(src->buf, dest->buf))
 353                                 continue;
 354                         if (option_local)
 355                                 die_errno(_("failed to create link '%s'"), dest->buf);
 356                         option_no_hardlinks = 1;
 357                 }
 358                 if (copy_file_with_time(dest->buf, src->buf, 0666))
 359                         die_errno(_("failed to copy file to '%s'"), dest->buf);
 360         }
 361         closedir(dir);
 362 }
 363
 364 static const struct ref *clone_local(const char *src_repo,
 365                                      const char *dest_repo)
 366 {
 367         const struct ref *ret;
 368         struct remote *remote;
 369         struct transport *transport;
 370
 371         if (option_shared) {
 372                 struct strbuf alt = STRBUF_INIT;
 373                 strbuf_addf(&alt, "%s/objects", src_repo);
 374                 add_to_alternates_file(alt.buf);
 375                 strbuf_release(&alt);
 376         } else {
 377                 struct strbuf src = STRBUF_INIT;
 378                 struct strbuf dest = STRBUF_INIT;
 379                 strbuf_addf(&src, "%s/objects", src_repo);
 380                 strbuf_addf(&dest, "%s/objects", dest_repo);
 381                 copy_or_link_directory(&src, &dest, src_repo, src.len);
 382                 strbuf_release(&src);
 383                 strbuf_release(&dest);
 384         }
 385
 386         remote = remote_get(src_repo);
 387         transport = transport_get(remote, src_repo);
 388         ret = transport_get_remote_refs(transport);
 389         transport_disconnect(transport);
 390         if (0 <= option_verbosity)
 391                 printf(_("done.\n"));
 392         return ret;
 393 }
 394
 395 static const char *junk_work_tree;
 396 static const char *junk_git_dir;
 397 static pid_t junk_pid;
 398
 399 static void remove_junk(void)
 400 {
 401         struct strbuf sb = STRBUF_INIT;
 402         if (getpid() != junk_pid)
 403                 return;
 404         if (junk_git_dir) {
 405                 strbuf_addstr(&sb, junk_git_dir);
 406                 remove_dir_recursively(&sb, 0);
 407                 strbuf_reset(&sb);
 408         }
 409         if (junk_work_tree) {
 410                 strbuf_addstr(&sb, junk_work_tree);
 411                 remove_dir_recursively(&sb, 0);
 412                 strbuf_reset(&sb);
 413         }
 414 }
 415
 416 static void remove_junk_on_signal(int signo)
 417 {
 418         remove_junk();
 419         sigchain_pop(signo);
 420         raise(signo);
 421 }
 422
 423 static struct ref *wanted_peer_refs(const struct ref *refs,
 424                 struct refspec *refspec)
 425 {
 426         struct ref *head = copy_ref(find_ref_by_name(refs, "HEAD"));
 427         struct ref *local_refs = head;
 428         struct ref **tail = head ? &head->next : &local_refs;
 429
 430         get_fetch_map(refs, refspec, &tail, 0);
 431         if (!option_mirror)
 432                 get_fetch_map(refs, tag_refspec, &tail, 0);
 433
 434         return local_refs;
 435 }
 436
 437 static void write_remote_refs(const struct ref *local_refs)
 438 {
 439         const struct ref *r;
 440
 441         for (r = local_refs; r; r = r->next) {
 442                 if (!r->peer_ref)
 443                         continue;
 444                 add_extra_ref(r->peer_ref->name, r->old_sha1, 0);
 445         }
 446
 447         pack_refs(PACK_REFS_ALL);
 448         clear_extra_refs();
 449 }
 450
 451 static int write_one_config(const char *key, const char *value, void *data)
 452 {
 453         return git_config_set_multivar(key, value ? value : "true", "^$", 0);
 454 }
 455
 456 static void write_config(struct string_list *config)
 457 {
 458         int i;
 459
 460         for (i = 0; i < config->nr; i++) {
 461                 if (git_config_parse_parameter(config->items[i].string,
 462                                                write_one_config, NULL) < 0)
 463                         die("unable to write parameters to config file");
 464         }
 465 }
 466
 467 int cmd_clone(int argc, const char **argv, const char *prefix)
 468 {
 469         int is_bundle = 0, is_local;
 470         struct stat buf;
 471         const char *repo_name, *repo, *work_tree, *git_dir;
 472         char *path, *dir;
 473         int dest_exists;
 474         const struct ref *refs, *remote_head;
 475         const struct ref *remote_head_points_at;
 476         const struct ref *our_head_points_at;
 477         struct ref *mapped_refs;
 478         struct strbuf key = STRBUF_INIT, value = STRBUF_INIT;
 479         struct strbuf branch_top = STRBUF_INIT, reflog_msg = STRBUF_INIT;
 480         struct transport *transport = NULL;
 481         char *src_ref_prefix = "refs/heads/";
 482         int err = 0;
 483
 484         struct refspec *refspec;
 485         const char *fetch_pattern;
 486
 487         junk_pid = getpid();
 488
 489         packet_trace_identity("clone");
 490         argc = parse_options(argc, argv, prefix, builtin_clone_options,
 491                              builtin_clone_usage, 0);
 492
 493         if (argc > 2)
 494                 usage_msg_opt(_("Too many arguments."),
 495                         builtin_clone_usage, builtin_clone_options);
 496
 497         if (argc == 0)
 498                 usage_msg_opt(_("You must specify a repository to clone."),
 499                         builtin_clone_usage, builtin_clone_options);
 500
 501         if (option_mirror)
 502                 option_bare = 1;
 503
 504         if (option_bare) {
 505                 if (option_origin)
 506                         die(_("--bare and --origin %s options are incompatible."),
 507                             option_origin);
 508                 option_no_checkout = 1;
 509         }
 510
 511         if (!option_origin)
 512                 option_origin = "origin";
 513
 514         repo_name = argv[0];
 515
 516         path = get_repo_path(repo_name, &is_bundle);
 517         if (path)
 518                 repo = xstrdup(absolute_path(repo_name));
 519         else if (!strchr(repo_name, ':'))
 520                 die(_("repository '%s' does not exist"), repo_name);
 521         else
 522                 repo = repo_name;
 523         is_local = path && !is_bundle;
 524         if (is_local && option_depth)
 525                 warning(_("--depth is ignored in local clones; use file:// instead."));
 526
 527         if (argc == 2)
 528                 dir = xstrdup(argv[1]);
 529         else
 530                 dir = guess_dir_name(repo_name, is_bundle, option_bare);
 531         strip_trailing_slashes(dir);
 532
 533         dest_exists = !stat(dir, &buf);
 534         if (dest_exists && !is_empty_dir(dir))
 535                 die(_("destination path '%s' already exists and is not "
 536                         "an empty directory."), dir);
 537
 538         strbuf_addf(&reflog_msg, "clone: from %s", repo);
 539
 540         if (option_bare)
 541                 work_tree = NULL;
 542         else {
 543                 work_tree = getenv("GIT_WORK_TREE");
 544                 if (work_tree && !stat(work_tree, &buf))
 545                         die(_("working tree '%s' already exists."), work_tree);
 546         }
 547
 548         if (option_bare || work_tree)
 549                 git_dir = xstrdup(dir);
 550         else {
 551                 work_tree = dir;
 552                 git_dir = xstrdup(mkpath("%s/.git", dir));
 553         }
 554
 555         if (!option_bare) {
 556                 junk_work_tree = work_tree;
 557                 if (safe_create_leading_directories_const(work_tree) < 0)
 558                         die_errno(_("could not create leading directories of '%s'"),
 559                                   work_tree);
 560                 if (!dest_exists && mkdir(work_tree, 0755))
 561                         die_errno(_("could not create work tree dir '%s'."),
 562                                   work_tree);
 563                 set_git_work_tree(work_tree);
 564         }
 565         junk_git_dir = git_dir;
 566         atexit(remove_junk);
 567         sigchain_push_common(remove_junk_on_signal);
 568
 569         setenv(CONFIG_ENVIRONMENT, mkpath("%s/config", git_dir), 1);
 570
 571         if (safe_create_leading_directories_const(git_dir) < 0)
 572                 die(_("could not create leading directories of '%s'"), git_dir);
 573
 574         set_git_dir_init(git_dir, real_git_dir, 0);
 575         if (real_git_dir)
 576                 git_dir = real_git_dir;
 577
 578         if (0 <= option_verbosity) {
 579                 if (option_bare)
 580                         printf(_("Cloning into bare repository '%s'...\n"), dir);
 581                 else
 582                         printf(_("Cloning into '%s'...\n"), dir);
 583         }
 584         init_db(option_template, INIT_DB_QUIET);
 585         write_config(&option_config);
 586
 587         /*
 588          * At this point, the config exists, so we do not need the
 589          * environment variable.  We actually need to unset it, too, to
 590          * re-enable parsing of the global configs.
 591          */
 592         unsetenv(CONFIG_ENVIRONMENT);
 593
 594         git_config(git_default_config, NULL);
 595
 596         if (option_bare) {
 597                 if (option_mirror)
 598                         src_ref_prefix = "refs/";
 599                 strbuf_addstr(&branch_top, src_ref_prefix);
 600
 601                 git_config_set("core.bare", "true");
 602         } else {
 603                 strbuf_addf(&branch_top, "refs/remotes/%s/", option_origin);
 604         }
 605
 606         strbuf_addf(&value, "+%s*:%s*", src_ref_prefix, branch_top.buf);
 607
 608         if (option_mirror || !option_bare) {
 609                 /* Configure the remote */
 610                 strbuf_addf(&key, "remote.%s.fetch", option_origin);
 611                 git_config_set_multivar(key.buf, value.buf, "^$", 0);
 612                 strbuf_reset(&key);
 613
 614                 if (option_mirror) {
 615                         strbuf_addf(&key, "remote.%s.mirror", option_origin);
 616                         git_config_set(key.buf, "true");
 617                         strbuf_reset(&key);
 618                 }
 619         }
 620
 621         strbuf_addf(&key, "remote.%s.url", option_origin);
 622         git_config_set(key.buf, repo);
 623         strbuf_reset(&key);
 624
 625         if (option_reference.nr)
 626                 setup_reference();
 627
 628         fetch_pattern = value.buf;
 629         refspec = parse_fetch_refspec(1, &fetch_pattern);
 630
 631         strbuf_reset(&value);
 632
 633         if (is_local) {
 634                 refs = clone_local(path, git_dir);
 635                 mapped_refs = wanted_peer_refs(refs, refspec);
 636         } else {
 637                 struct remote *remote = remote_get(option_origin);
 638                 transport = transport_get(remote, remote->url[0]);
 639
 640                 if (!transport->get_refs_list || !transport->fetch)
 641                         die(_("Don't know how to clone %s"), transport->url);
 642
 643                 transport_set_option(transport, TRANS_OPT_KEEP, "yes");
 644
 645                 if (option_depth)
 646                         transport_set_option(transport, TRANS_OPT_DEPTH,
 647                                              option_depth);
 648
 649                 transport_set_verbosity(transport, option_verbosity, option_progress);
 650
 651                 if (option_upload_pack)
 652                         transport_set_option(transport, TRANS_OPT_UPLOADPACK,
 653                                              option_upload_pack);
 654
 655                 refs = transport_get_remote_refs(transport);
 656                 if (refs) {
 657                         mapped_refs = wanted_peer_refs(refs, refspec);
 658                         transport_fetch_refs(transport, mapped_refs);
 659                 }
 660         }
 661
 662         if (refs) {
 663                 clear_extra_refs();
 664
 665                 write_remote_refs(mapped_refs);
 666
 667                 remote_head = find_ref_by_name(refs, "HEAD");
 668                 remote_head_points_at =
 669                         guess_remote_head(remote_head, mapped_refs, 0);
 670
 671                 if (option_branch) {
 672                         struct strbuf head = STRBUF_INIT;
 673                         strbuf_addstr(&head, src_ref_prefix);
 674                         strbuf_addstr(&head, option_branch);
 675                         our_head_points_at =
 676                                 find_ref_by_name(mapped_refs, head.buf);
 677                         strbuf_release(&head);
 678
 679                         if (!our_head_points_at) {
 680                                 warning(_("Remote branch %s not found in "
 681                                         "upstream %s, using HEAD instead"),
 682                                         option_branch, option_origin);
 683                                 our_head_points_at = remote_head_points_at;
 684                         }
 685                 }
 686                 else
 687                         our_head_points_at = remote_head_points_at;
 688         }
 689         else {
 690                 warning(_("You appear to have cloned an empty repository."));
 691                 our_head_points_at = NULL;
 692                 remote_head_points_at = NULL;
 693                 remote_head = NULL;
 694                 option_no_checkout = 1;
 695                 if (!option_bare)
 696                         install_branch_config(0, "master", option_origin,
 697                                               "refs/heads/master");
 698         }
 699
 700         if (remote_head_points_at && !option_bare) {
 701                 struct strbuf head_ref = STRBUF_INIT;
 702                 strbuf_addstr(&head_ref, branch_top.buf);
 703                 strbuf_addstr(&head_ref, "HEAD");
 704                 create_symref(head_ref.buf,
 705                               remote_head_points_at->peer_ref->name,
 706                               reflog_msg.buf);
 707         }
 708
 709         if (our_head_points_at) {
 710                 /* Local default branch link */
 711                 create_symref("HEAD", our_head_points_at->name, NULL);
 712                 if (!option_bare) {
 713                         const char *head = skip_prefix(our_head_points_at->name,
 714                                                        "refs/heads/");
 715                         update_ref(reflog_msg.buf, "HEAD",
 716                                    our_head_points_at->old_sha1,
 717                                    NULL, 0, DIE_ON_ERR);
 718                         install_branch_config(0, head, option_origin,
 719                                               our_head_points_at->name);
 720                 }
 721         } else if (remote_head) {
 722                 /* Source had detached HEAD pointing somewhere. */
 723                 if (!option_bare) {
 724                         update_ref(reflog_msg.buf, "HEAD",
 725                                    remote_head->old_sha1,
 726                                    NULL, REF_NODEREF, DIE_ON_ERR);
 727                         our_head_points_at = remote_head;
 728                 }
 729         } else {
 730                 /* Nothing to checkout out */
 731                 if (!option_no_checkout)
 732                         warning(_("remote HEAD refers to nonexistent ref, "
 733                                 "unable to checkout.\n"));
 734                 option_no_checkout = 1;
 735         }
 736
 737         if (transport) {
 738                 transport_unlock_pack(transport);
 739                 transport_disconnect(transport);
 740         }
 741
 742         if (!option_no_checkout) {
 743                 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 744                 struct unpack_trees_options opts;
 745                 struct tree *tree;
 746                 struct tree_desc t;
 747                 int fd;
 748
 749                 /* We need to be in the new work tree for the checkout */
 750                 setup_work_tree();
 751
 752                 fd = hold_locked_index(lock_file, 1);
 753
 754                 memset(&opts, 0, sizeof opts);
 755                 opts.update = 1;
 756                 opts.merge = 1;
 757                 opts.fn = oneway_merge;
 758                 opts.verbose_update = (option_verbosity > 0);
 759                 opts.src_index = &the_index;
 760                 opts.dst_index = &the_index;
 761
 762                 tree = parse_tree_indirect(our_head_points_at->old_sha1);
 763                 parse_tree(tree);
 764                 init_tree_desc(&t, tree->buffer, tree->size);
 765                 unpack_trees(1, &t, &opts);
 766
 767                 if (write_cache(fd, active_cache, active_nr) ||
 768                     commit_locked_index(lock_file))
 769                         die(_("unable to write new index file"));
 770
 771                 err |= run_hook(NULL, "post-checkout", sha1_to_hex(null_sha1),
 772                                 sha1_to_hex(our_head_points_at->old_sha1), "1",
 773                                 NULL);
 774
 775                 if (!err && option_recursive)
 776                         err = run_command_v_opt(argv_submodule, RUN_GIT_CMD);
 777         }
 778
 779         strbuf_release(&reflog_msg);
 780         strbuf_release(&branch_top);
 781         strbuf_release(&key);
 782         strbuf_release(&value);
 783         junk_pid = 0;
 784         return err;
 785 }