Merge branch 'jk/name-hash-dirent'
[git] / 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 (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 }