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