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