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