Merge branch 'ab/newhash-is-sha256'
[git] / builtin / checkout.c
1 #include "builtin.h"
2 #include "config.h"
3 #include "checkout.h"
4 #include "lockfile.h"
5 #include "parse-options.h"
6 #include "refs.h"
7 #include "object-store.h"
8 #include "commit.h"
9 #include "tree.h"
10 #include "tree-walk.h"
11 #include "cache-tree.h"
12 #include "unpack-trees.h"
13 #include "dir.h"
14 #include "run-command.h"
15 #include "merge-recursive.h"
16 #include "branch.h"
17 #include "diff.h"
18 #include "revision.h"
19 #include "remote.h"
20 #include "blob.h"
21 #include "xdiff-interface.h"
22 #include "ll-merge.h"
23 #include "resolve-undo.h"
24 #include "submodule-config.h"
25 #include "submodule.h"
26 #include "advice.h"
27
28 static const char * const checkout_usage[] = {
29         N_("git checkout [<options>] <branch>"),
30         N_("git checkout [<options>] [<branch>] -- <file>..."),
31         NULL,
32 };
33
34 struct checkout_opts {
35         int patch_mode;
36         int quiet;
37         int merge;
38         int force;
39         int force_detach;
40         int writeout_stage;
41         int overwrite_ignore;
42         int ignore_skipworktree;
43         int ignore_other_worktrees;
44         int show_progress;
45
46         const char *new_branch;
47         const char *new_branch_force;
48         const char *new_orphan_branch;
49         int new_branch_log;
50         enum branch_track track;
51         struct diff_options diff_options;
52
53         int branch_exists;
54         const char *prefix;
55         struct pathspec pathspec;
56         struct tree *source_tree;
57 };
58
59 static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
60                               int changed)
61 {
62         return run_hook_le(NULL, "post-checkout",
63                            oid_to_hex(old_commit ? &old_commit->object.oid : &null_oid),
64                            oid_to_hex(new_commit ? &new_commit->object.oid : &null_oid),
65                            changed ? "1" : "0", NULL);
66         /* "new_commit" can be NULL when checking out from the index before
67            a commit exists. */
68
69 }
70
71 static int update_some(const struct object_id *oid, struct strbuf *base,
72                 const char *pathname, unsigned mode, int stage, void *context)
73 {
74         int len;
75         struct cache_entry *ce;
76         int pos;
77
78         if (S_ISDIR(mode))
79                 return READ_TREE_RECURSIVE;
80
81         len = base->len + strlen(pathname);
82         ce = make_empty_cache_entry(&the_index, len);
83         oidcpy(&ce->oid, oid);
84         memcpy(ce->name, base->buf, base->len);
85         memcpy(ce->name + base->len, pathname, len - base->len);
86         ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
87         ce->ce_namelen = len;
88         ce->ce_mode = create_ce_mode(mode);
89
90         /*
91          * If the entry is the same as the current index, we can leave the old
92          * entry in place. Whether it is UPTODATE or not, checkout_entry will
93          * do the right thing.
94          */
95         pos = cache_name_pos(ce->name, ce->ce_namelen);
96         if (pos >= 0) {
97                 struct cache_entry *old = active_cache[pos];
98                 if (ce->ce_mode == old->ce_mode &&
99                     !oidcmp(&ce->oid, &old->oid)) {
100                         old->ce_flags |= CE_UPDATE;
101                         discard_cache_entry(ce);
102                         return 0;
103                 }
104         }
105
106         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
107         return 0;
108 }
109
110 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
111 {
112         read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
113
114         /* update the index with the given tree's info
115          * for all args, expanding wildcards, and exit
116          * with any non-zero return code.
117          */
118         return 0;
119 }
120
121 static int skip_same_name(const struct cache_entry *ce, int pos)
122 {
123         while (++pos < active_nr &&
124                !strcmp(active_cache[pos]->name, ce->name))
125                 ; /* skip */
126         return pos;
127 }
128
129 static int check_stage(int stage, const struct cache_entry *ce, int pos)
130 {
131         while (pos < active_nr &&
132                !strcmp(active_cache[pos]->name, ce->name)) {
133                 if (ce_stage(active_cache[pos]) == stage)
134                         return 0;
135                 pos++;
136         }
137         if (stage == 2)
138                 return error(_("path '%s' does not have our version"), ce->name);
139         else
140                 return error(_("path '%s' does not have their version"), ce->name);
141 }
142
143 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
144 {
145         unsigned seen = 0;
146         const char *name = ce->name;
147
148         while (pos < active_nr) {
149                 ce = active_cache[pos];
150                 if (strcmp(name, ce->name))
151                         break;
152                 seen |= (1 << ce_stage(ce));
153                 pos++;
154         }
155         if ((stages & seen) != stages)
156                 return error(_("path '%s' does not have all necessary versions"),
157                              name);
158         return 0;
159 }
160
161 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
162                           const struct checkout *state)
163 {
164         while (pos < active_nr &&
165                !strcmp(active_cache[pos]->name, ce->name)) {
166                 if (ce_stage(active_cache[pos]) == stage)
167                         return checkout_entry(active_cache[pos], state, NULL);
168                 pos++;
169         }
170         if (stage == 2)
171                 return error(_("path '%s' does not have our version"), ce->name);
172         else
173                 return error(_("path '%s' does not have their version"), ce->name);
174 }
175
176 static int checkout_merged(int pos, const struct checkout *state)
177 {
178         struct cache_entry *ce = active_cache[pos];
179         const char *path = ce->name;
180         mmfile_t ancestor, ours, theirs;
181         int status;
182         struct object_id oid;
183         mmbuffer_t result_buf;
184         struct object_id threeway[3];
185         unsigned mode = 0;
186
187         memset(threeway, 0, sizeof(threeway));
188         while (pos < active_nr) {
189                 int stage;
190                 stage = ce_stage(ce);
191                 if (!stage || strcmp(path, ce->name))
192                         break;
193                 oidcpy(&threeway[stage - 1], &ce->oid);
194                 if (stage == 2)
195                         mode = create_ce_mode(ce->ce_mode);
196                 pos++;
197                 ce = active_cache[pos];
198         }
199         if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
200                 return error(_("path '%s' does not have necessary versions"), path);
201
202         read_mmblob(&ancestor, &threeway[0]);
203         read_mmblob(&ours, &threeway[1]);
204         read_mmblob(&theirs, &threeway[2]);
205
206         /*
207          * NEEDSWORK: re-create conflicts from merges with
208          * merge.renormalize set, too
209          */
210         status = ll_merge(&result_buf, path, &ancestor, "base",
211                           &ours, "ours", &theirs, "theirs", NULL);
212         free(ancestor.ptr);
213         free(ours.ptr);
214         free(theirs.ptr);
215         if (status < 0 || !result_buf.ptr) {
216                 free(result_buf.ptr);
217                 return error(_("path '%s': cannot merge"), path);
218         }
219
220         /*
221          * NEEDSWORK:
222          * There is absolutely no reason to write this as a blob object
223          * and create a phony cache entry.  This hack is primarily to get
224          * to the write_entry() machinery that massages the contents to
225          * work-tree format and writes out which only allows it for a
226          * cache entry.  The code in write_entry() needs to be refactored
227          * to allow us to feed a <buffer, size, mode> instead of a cache
228          * entry.  Such a refactoring would help merge_recursive as well
229          * (it also writes the merge result to the object database even
230          * when it may contain conflicts).
231          */
232         if (write_object_file(result_buf.ptr, result_buf.size, blob_type, &oid))
233                 die(_("Unable to add merge result for '%s'"), path);
234         free(result_buf.ptr);
235         ce = make_transient_cache_entry(mode, &oid, path, 2);
236         if (!ce)
237                 die(_("make_cache_entry failed for path '%s'"), path);
238         status = checkout_entry(ce, state, NULL);
239         discard_cache_entry(ce);
240         return status;
241 }
242
243 static int checkout_paths(const struct checkout_opts *opts,
244                           const char *revision)
245 {
246         int pos;
247         struct checkout state = CHECKOUT_INIT;
248         static char *ps_matched;
249         struct object_id rev;
250         struct commit *head;
251         int errs = 0;
252         struct lock_file lock_file = LOCK_INIT;
253
254         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
255                 die(_("'%s' cannot be used with updating paths"), "--track");
256
257         if (opts->new_branch_log)
258                 die(_("'%s' cannot be used with updating paths"), "-l");
259
260         if (opts->force && opts->patch_mode)
261                 die(_("'%s' cannot be used with updating paths"), "-f");
262
263         if (opts->force_detach)
264                 die(_("'%s' cannot be used with updating paths"), "--detach");
265
266         if (opts->merge && opts->patch_mode)
267                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
268
269         if (opts->force && opts->merge)
270                 die(_("'%s' cannot be used with %s"), "-f", "-m");
271
272         if (opts->new_branch)
273                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
274                     opts->new_branch);
275
276         if (opts->patch_mode)
277                 return run_add_interactive(revision, "--patch=checkout",
278                                            &opts->pathspec);
279
280         hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
281         if (read_cache_preload(&opts->pathspec) < 0)
282                 return error(_("index file corrupt"));
283
284         if (opts->source_tree)
285                 read_tree_some(opts->source_tree, &opts->pathspec);
286
287         ps_matched = xcalloc(opts->pathspec.nr, 1);
288
289         /*
290          * Make sure all pathspecs participated in locating the paths
291          * to be checked out.
292          */
293         for (pos = 0; pos < active_nr; pos++) {
294                 struct cache_entry *ce = active_cache[pos];
295                 ce->ce_flags &= ~CE_MATCHED;
296                 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
297                         continue;
298                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
299                         /*
300                          * "git checkout tree-ish -- path", but this entry
301                          * is in the original index; it will not be checked
302                          * out to the working tree and it does not matter
303                          * if pathspec matched this entry.  We will not do
304                          * anything to this entry at all.
305                          */
306                         continue;
307                 /*
308                  * Either this entry came from the tree-ish we are
309                  * checking the paths out of, or we are checking out
310                  * of the index.
311                  *
312                  * If it comes from the tree-ish, we already know it
313                  * matches the pathspec and could just stamp
314                  * CE_MATCHED to it from update_some(). But we still
315                  * need ps_matched and read_tree_recursive (and
316                  * eventually tree_entry_interesting) cannot fill
317                  * ps_matched yet. Once it can, we can avoid calling
318                  * match_pathspec() for _all_ entries when
319                  * opts->source_tree != NULL.
320                  */
321                 if (ce_path_match(ce, &opts->pathspec, ps_matched))
322                         ce->ce_flags |= CE_MATCHED;
323         }
324
325         if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
326                 free(ps_matched);
327                 return 1;
328         }
329         free(ps_matched);
330
331         /* "checkout -m path" to recreate conflicted state */
332         if (opts->merge)
333                 unmerge_marked_index(&the_index);
334
335         /* Any unmerged paths? */
336         for (pos = 0; pos < active_nr; pos++) {
337                 const struct cache_entry *ce = active_cache[pos];
338                 if (ce->ce_flags & CE_MATCHED) {
339                         if (!ce_stage(ce))
340                                 continue;
341                         if (opts->force) {
342                                 warning(_("path '%s' is unmerged"), ce->name);
343                         } else if (opts->writeout_stage) {
344                                 errs |= check_stage(opts->writeout_stage, ce, pos);
345                         } else if (opts->merge) {
346                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
347                         } else {
348                                 errs = 1;
349                                 error(_("path '%s' is unmerged"), ce->name);
350                         }
351                         pos = skip_same_name(ce, pos) - 1;
352                 }
353         }
354         if (errs)
355                 return 1;
356
357         /* Now we are committed to check them out */
358         state.force = 1;
359         state.refresh_cache = 1;
360         state.istate = &the_index;
361
362         enable_delayed_checkout(&state);
363         for (pos = 0; pos < active_nr; pos++) {
364                 struct cache_entry *ce = active_cache[pos];
365                 if (ce->ce_flags & CE_MATCHED) {
366                         if (!ce_stage(ce)) {
367                                 errs |= checkout_entry(ce, &state, NULL);
368                                 continue;
369                         }
370                         if (opts->writeout_stage)
371                                 errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
372                         else if (opts->merge)
373                                 errs |= checkout_merged(pos, &state);
374                         pos = skip_same_name(ce, pos) - 1;
375                 }
376         }
377         errs |= finish_delayed_checkout(&state);
378
379         if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
380                 die(_("unable to write new index file"));
381
382         read_ref_full("HEAD", 0, &rev, NULL);
383         head = lookup_commit_reference_gently(the_repository, &rev, 1);
384
385         errs |= post_checkout_hook(head, head, 0);
386         return errs;
387 }
388
389 static void show_local_changes(struct object *head,
390                                const struct diff_options *opts)
391 {
392         struct rev_info rev;
393         /* I think we want full paths, even if we're in a subdirectory. */
394         init_revisions(&rev, NULL);
395         rev.diffopt.flags = opts->flags;
396         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
397         diff_setup_done(&rev.diffopt);
398         add_pending_object(&rev, head, NULL);
399         run_diff_index(&rev, 0);
400 }
401
402 static void describe_detached_head(const char *msg, struct commit *commit)
403 {
404         struct strbuf sb = STRBUF_INIT;
405
406         if (!parse_commit(commit))
407                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
408         if (print_sha1_ellipsis()) {
409                 fprintf(stderr, "%s %s... %s\n", msg,
410                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
411         } else {
412                 fprintf(stderr, "%s %s %s\n", msg,
413                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
414         }
415         strbuf_release(&sb);
416 }
417
418 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
419                       int worktree, int *writeout_error)
420 {
421         struct unpack_trees_options opts;
422         struct tree_desc tree_desc;
423
424         memset(&opts, 0, sizeof(opts));
425         opts.head_idx = -1;
426         opts.update = worktree;
427         opts.skip_unmerged = !worktree;
428         opts.reset = 1;
429         opts.merge = 1;
430         opts.fn = oneway_merge;
431         opts.verbose_update = o->show_progress;
432         opts.src_index = &the_index;
433         opts.dst_index = &the_index;
434         parse_tree(tree);
435         init_tree_desc(&tree_desc, tree->buffer, tree->size);
436         switch (unpack_trees(1, &tree_desc, &opts)) {
437         case -2:
438                 *writeout_error = 1;
439                 /*
440                  * We return 0 nevertheless, as the index is all right
441                  * and more importantly we have made best efforts to
442                  * update paths in the work tree, and we cannot revert
443                  * them.
444                  */
445                 /* fallthrough */
446         case 0:
447                 return 0;
448         default:
449                 return 128;
450         }
451 }
452
453 struct branch_info {
454         const char *name; /* The short name used */
455         const char *path; /* The full name of a real branch */
456         struct commit *commit; /* The named commit */
457         /*
458          * if not null the branch is detached because it's already
459          * checked out in this checkout
460          */
461         char *checkout;
462 };
463
464 static void setup_branch_path(struct branch_info *branch)
465 {
466         struct strbuf buf = STRBUF_INIT;
467
468         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
469         if (strcmp(buf.buf, branch->name))
470                 branch->name = xstrdup(buf.buf);
471         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
472         branch->path = strbuf_detach(&buf, NULL);
473 }
474
475 static int merge_working_tree(const struct checkout_opts *opts,
476                               struct branch_info *old_branch_info,
477                               struct branch_info *new_branch_info,
478                               int *writeout_error)
479 {
480         int ret;
481         struct lock_file lock_file = LOCK_INIT;
482
483         hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
484         if (read_cache_preload(NULL) < 0)
485                 return error(_("index file corrupt"));
486
487         resolve_undo_clear();
488         if (opts->force) {
489                 ret = reset_tree(get_commit_tree(new_branch_info->commit),
490                                  opts, 1, writeout_error);
491                 if (ret)
492                         return ret;
493         } else {
494                 struct tree_desc trees[2];
495                 struct tree *tree;
496                 struct unpack_trees_options topts;
497
498                 memset(&topts, 0, sizeof(topts));
499                 topts.head_idx = -1;
500                 topts.src_index = &the_index;
501                 topts.dst_index = &the_index;
502
503                 setup_unpack_trees_porcelain(&topts, "checkout");
504
505                 refresh_cache(REFRESH_QUIET);
506
507                 if (unmerged_cache()) {
508                         error(_("you need to resolve your current index first"));
509                         return 1;
510                 }
511
512                 /* 2-way merge to the new branch */
513                 topts.initial_checkout = is_cache_unborn();
514                 topts.update = 1;
515                 topts.merge = 1;
516                 topts.gently = opts->merge && old_branch_info->commit;
517                 topts.verbose_update = opts->show_progress;
518                 topts.fn = twoway_merge;
519                 if (opts->overwrite_ignore) {
520                         topts.dir = xcalloc(1, sizeof(*topts.dir));
521                         topts.dir->flags |= DIR_SHOW_IGNORED;
522                         setup_standard_excludes(topts.dir);
523                 }
524                 tree = parse_tree_indirect(old_branch_info->commit ?
525                                            &old_branch_info->commit->object.oid :
526                                            the_hash_algo->empty_tree);
527                 init_tree_desc(&trees[0], tree->buffer, tree->size);
528                 tree = parse_tree_indirect(&new_branch_info->commit->object.oid);
529                 init_tree_desc(&trees[1], tree->buffer, tree->size);
530
531                 ret = unpack_trees(2, trees, &topts);
532                 clear_unpack_trees_porcelain(&topts);
533                 if (ret == -1) {
534                         /*
535                          * Unpack couldn't do a trivial merge; either
536                          * give up or do a real merge, depending on
537                          * whether the merge flag was used.
538                          */
539                         struct tree *result;
540                         struct tree *work;
541                         struct merge_options o;
542                         if (!opts->merge)
543                                 return 1;
544
545                         /*
546                          * Without old_branch_info->commit, the below is the same as
547                          * the two-tree unpack we already tried and failed.
548                          */
549                         if (!old_branch_info->commit)
550                                 return 1;
551
552                         /* Do more real merge */
553
554                         /*
555                          * We update the index fully, then write the
556                          * tree from the index, then merge the new
557                          * branch with the current tree, with the old
558                          * branch as the base. Then we reset the index
559                          * (but not the working tree) to the new
560                          * branch, leaving the working tree as the
561                          * merged version, but skipping unmerged
562                          * entries in the index.
563                          */
564
565                         add_files_to_cache(NULL, NULL, 0);
566                         /*
567                          * NEEDSWORK: carrying over local changes
568                          * when branches have different end-of-line
569                          * normalization (or clean+smudge rules) is
570                          * a pain; plumb in an option to set
571                          * o.renormalize?
572                          */
573                         init_merge_options(&o);
574                         o.verbosity = 0;
575                         work = write_tree_from_memory(&o);
576
577                         ret = reset_tree(get_commit_tree(new_branch_info->commit),
578                                          opts, 1,
579                                          writeout_error);
580                         if (ret)
581                                 return ret;
582                         o.ancestor = old_branch_info->name;
583                         o.branch1 = new_branch_info->name;
584                         o.branch2 = "local";
585                         ret = merge_trees(&o,
586                                           get_commit_tree(new_branch_info->commit),
587                                           work,
588                                           get_commit_tree(old_branch_info->commit),
589                                           &result);
590                         if (ret < 0)
591                                 exit(128);
592                         ret = reset_tree(get_commit_tree(new_branch_info->commit),
593                                          opts, 0,
594                                          writeout_error);
595                         strbuf_release(&o.obuf);
596                         if (ret)
597                                 return ret;
598                 }
599         }
600
601         if (!active_cache_tree)
602                 active_cache_tree = cache_tree();
603
604         if (!cache_tree_fully_valid(active_cache_tree))
605                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
606
607         if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
608                 die(_("unable to write new index file"));
609
610         if (!opts->force && !opts->quiet)
611                 show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
612
613         return 0;
614 }
615
616 static void report_tracking(struct branch_info *new_branch_info)
617 {
618         struct strbuf sb = STRBUF_INIT;
619         struct branch *branch = branch_get(new_branch_info->name);
620
621         if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL))
622                 return;
623         fputs(sb.buf, stdout);
624         strbuf_release(&sb);
625 }
626
627 static void update_refs_for_switch(const struct checkout_opts *opts,
628                                    struct branch_info *old_branch_info,
629                                    struct branch_info *new_branch_info)
630 {
631         struct strbuf msg = STRBUF_INIT;
632         const char *old_desc, *reflog_msg;
633         if (opts->new_branch) {
634                 if (opts->new_orphan_branch) {
635                         char *refname;
636
637                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
638                         if (opts->new_branch_log &&
639                             !should_autocreate_reflog(refname)) {
640                                 int ret;
641                                 struct strbuf err = STRBUF_INIT;
642
643                                 ret = safe_create_reflog(refname, 1, &err);
644                                 if (ret) {
645                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
646                                                 opts->new_orphan_branch, err.buf);
647                                         strbuf_release(&err);
648                                         free(refname);
649                                         return;
650                                 }
651                                 strbuf_release(&err);
652                         }
653                         free(refname);
654                 }
655                 else
656                         create_branch(opts->new_branch, new_branch_info->name,
657                                       opts->new_branch_force ? 1 : 0,
658                                       opts->new_branch_force ? 1 : 0,
659                                       opts->new_branch_log,
660                                       opts->quiet,
661                                       opts->track);
662                 new_branch_info->name = opts->new_branch;
663                 setup_branch_path(new_branch_info);
664         }
665
666         old_desc = old_branch_info->name;
667         if (!old_desc && old_branch_info->commit)
668                 old_desc = oid_to_hex(&old_branch_info->commit->object.oid);
669
670         reflog_msg = getenv("GIT_REFLOG_ACTION");
671         if (!reflog_msg)
672                 strbuf_addf(&msg, "checkout: moving from %s to %s",
673                         old_desc ? old_desc : "(invalid)", new_branch_info->name);
674         else
675                 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
676
677         if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
678                 /* Nothing to do. */
679         } else if (opts->force_detach || !new_branch_info->path) {      /* No longer on any branch. */
680                 update_ref(msg.buf, "HEAD", &new_branch_info->commit->object.oid, NULL,
681                            REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
682                 if (!opts->quiet) {
683                         if (old_branch_info->path &&
684                             advice_detached_head && !opts->force_detach)
685                                 detach_advice(new_branch_info->name);
686                         describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
687                 }
688         } else if (new_branch_info->path) {     /* Switch branches. */
689                 if (create_symref("HEAD", new_branch_info->path, msg.buf) < 0)
690                         die(_("unable to update HEAD"));
691                 if (!opts->quiet) {
692                         if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
693                                 if (opts->new_branch_force)
694                                         fprintf(stderr, _("Reset branch '%s'\n"),
695                                                 new_branch_info->name);
696                                 else
697                                         fprintf(stderr, _("Already on '%s'\n"),
698                                                 new_branch_info->name);
699                         } else if (opts->new_branch) {
700                                 if (opts->branch_exists)
701                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new_branch_info->name);
702                                 else
703                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new_branch_info->name);
704                         } else {
705                                 fprintf(stderr, _("Switched to branch '%s'\n"),
706                                         new_branch_info->name);
707                         }
708                 }
709                 if (old_branch_info->path && old_branch_info->name) {
710                         if (!ref_exists(old_branch_info->path) && reflog_exists(old_branch_info->path))
711                                 delete_reflog(old_branch_info->path);
712                 }
713         }
714         remove_branch_state();
715         strbuf_release(&msg);
716         if (!opts->quiet &&
717             (new_branch_info->path || (!opts->force_detach && !strcmp(new_branch_info->name, "HEAD"))))
718                 report_tracking(new_branch_info);
719 }
720
721 static int add_pending_uninteresting_ref(const char *refname,
722                                          const struct object_id *oid,
723                                          int flags, void *cb_data)
724 {
725         add_pending_oid(cb_data, refname, oid, UNINTERESTING);
726         return 0;
727 }
728
729 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
730 {
731         strbuf_addstr(sb, "  ");
732         strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
733         strbuf_addch(sb, ' ');
734         if (!parse_commit(commit))
735                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
736         strbuf_addch(sb, '\n');
737 }
738
739 #define ORPHAN_CUTOFF 4
740 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
741 {
742         struct commit *c, *last = NULL;
743         struct strbuf sb = STRBUF_INIT;
744         int lost = 0;
745         while ((c = get_revision(revs)) != NULL) {
746                 if (lost < ORPHAN_CUTOFF)
747                         describe_one_orphan(&sb, c);
748                 last = c;
749                 lost++;
750         }
751         if (ORPHAN_CUTOFF < lost) {
752                 int more = lost - ORPHAN_CUTOFF;
753                 if (more == 1)
754                         describe_one_orphan(&sb, last);
755                 else
756                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
757         }
758
759         fprintf(stderr,
760                 Q_(
761                 /* The singular version */
762                 "Warning: you are leaving %d commit behind, "
763                 "not connected to\n"
764                 "any of your branches:\n\n"
765                 "%s\n",
766                 /* The plural version */
767                 "Warning: you are leaving %d commits behind, "
768                 "not connected to\n"
769                 "any of your branches:\n\n"
770                 "%s\n",
771                 /* Give ngettext() the count */
772                 lost),
773                 lost,
774                 sb.buf);
775         strbuf_release(&sb);
776
777         if (advice_detached_head)
778                 fprintf(stderr,
779                         Q_(
780                         /* The singular version */
781                         "If you want to keep it by creating a new branch, "
782                         "this may be a good time\nto do so with:\n\n"
783                         " git branch <new-branch-name> %s\n\n",
784                         /* The plural version */
785                         "If you want to keep them by creating a new branch, "
786                         "this may be a good time\nto do so with:\n\n"
787                         " git branch <new-branch-name> %s\n\n",
788                         /* Give ngettext() the count */
789                         lost),
790                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
791 }
792
793 /*
794  * We are about to leave commit that was at the tip of a detached
795  * HEAD.  If it is not reachable from any ref, this is the last chance
796  * for the user to do so without resorting to reflog.
797  */
798 static void orphaned_commit_warning(struct commit *old_commit, struct commit *new_commit)
799 {
800         struct rev_info revs;
801         struct object *object = &old_commit->object;
802
803         init_revisions(&revs, NULL);
804         setup_revisions(0, NULL, &revs, NULL);
805
806         object->flags &= ~UNINTERESTING;
807         add_pending_object(&revs, object, oid_to_hex(&object->oid));
808
809         for_each_ref(add_pending_uninteresting_ref, &revs);
810         add_pending_oid(&revs, "HEAD", &new_commit->object.oid, UNINTERESTING);
811
812         if (prepare_revision_walk(&revs))
813                 die(_("internal error in revision walk"));
814         if (!(old_commit->object.flags & UNINTERESTING))
815                 suggest_reattach(old_commit, &revs);
816         else
817                 describe_detached_head(_("Previous HEAD position was"), old_commit);
818
819         /* Clean up objects used, as they will be reused. */
820         clear_commit_marks_all(ALL_REV_FLAGS);
821 }
822
823 static int switch_branches(const struct checkout_opts *opts,
824                            struct branch_info *new_branch_info)
825 {
826         int ret = 0;
827         struct branch_info old_branch_info;
828         void *path_to_free;
829         struct object_id rev;
830         int flag, writeout_error = 0;
831         memset(&old_branch_info, 0, sizeof(old_branch_info));
832         old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
833         if (old_branch_info.path)
834                 old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
835         if (!(flag & REF_ISSYMREF))
836                 old_branch_info.path = NULL;
837
838         if (old_branch_info.path)
839                 skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
840
841         if (!new_branch_info->name) {
842                 new_branch_info->name = "HEAD";
843                 new_branch_info->commit = old_branch_info.commit;
844                 if (!new_branch_info->commit)
845                         die(_("You are on a branch yet to be born"));
846                 parse_commit_or_die(new_branch_info->commit);
847         }
848
849         ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error);
850         if (ret) {
851                 free(path_to_free);
852                 return ret;
853         }
854
855         if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit)
856                 orphaned_commit_warning(old_branch_info.commit, new_branch_info->commit);
857
858         update_refs_for_switch(opts, &old_branch_info, new_branch_info);
859
860         ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
861         free(path_to_free);
862         return ret || writeout_error;
863 }
864
865 static int git_checkout_config(const char *var, const char *value, void *cb)
866 {
867         if (!strcmp(var, "diff.ignoresubmodules")) {
868                 struct checkout_opts *opts = cb;
869                 handle_ignore_submodules_arg(&opts->diff_options, value);
870                 return 0;
871         }
872
873         if (starts_with(var, "submodule."))
874                 return git_default_submodule_config(var, value, NULL);
875
876         return git_xmerge_config(var, value, NULL);
877 }
878
879 static int parse_branchname_arg(int argc, const char **argv,
880                                 int dwim_new_local_branch_ok,
881                                 struct branch_info *new_branch_info,
882                                 struct checkout_opts *opts,
883                                 struct object_id *rev,
884                                 int *dwim_remotes_matched)
885 {
886         struct tree **source_tree = &opts->source_tree;
887         const char **new_branch = &opts->new_branch;
888         int argcount = 0;
889         struct object_id branch_rev;
890         const char *arg;
891         int dash_dash_pos;
892         int has_dash_dash = 0;
893         int i;
894
895         /*
896          * case 1: git checkout <ref> -- [<paths>]
897          *
898          *   <ref> must be a valid tree, everything after the '--' must be
899          *   a path.
900          *
901          * case 2: git checkout -- [<paths>]
902          *
903          *   everything after the '--' must be paths.
904          *
905          * case 3: git checkout <something> [--]
906          *
907          *   (a) If <something> is a commit, that is to
908          *       switch to the branch or detach HEAD at it.  As a special case,
909          *       if <something> is A...B (missing A or B means HEAD but you can
910          *       omit at most one side), and if there is a unique merge base
911          *       between A and B, A...B names that merge base.
912          *
913          *   (b) If <something> is _not_ a commit, either "--" is present
914          *       or <something> is not a path, no -t or -b was given, and
915          *       and there is a tracking branch whose name is <something>
916          *       in one and only one remote (or if the branch exists on the
917          *       remote named in checkout.defaultRemote), then this is a
918          *       short-hand to fork local <something> from that
919          *       remote-tracking branch.
920          *
921          *   (c) Otherwise, if "--" is present, treat it like case (1).
922          *
923          *   (d) Otherwise :
924          *       - if it's a reference, treat it like case (1)
925          *       - else if it's a path, treat it like case (2)
926          *       - else: fail.
927          *
928          * case 4: git checkout <something> <paths>
929          *
930          *   The first argument must not be ambiguous.
931          *   - If it's *only* a reference, treat it like case (1).
932          *   - If it's only a path, treat it like case (2).
933          *   - else: fail.
934          *
935          */
936         if (!argc)
937                 return 0;
938
939         arg = argv[0];
940         dash_dash_pos = -1;
941         for (i = 0; i < argc; i++) {
942                 if (!strcmp(argv[i], "--")) {
943                         dash_dash_pos = i;
944                         break;
945                 }
946         }
947         if (dash_dash_pos == 0)
948                 return 1; /* case (2) */
949         else if (dash_dash_pos == 1)
950                 has_dash_dash = 1; /* case (3) or (1) */
951         else if (dash_dash_pos >= 2)
952                 die(_("only one reference expected, %d given."), dash_dash_pos);
953
954         if (!strcmp(arg, "-"))
955                 arg = "@{-1}";
956
957         if (get_oid_mb(arg, rev)) {
958                 /*
959                  * Either case (3) or (4), with <something> not being
960                  * a commit, or an attempt to use case (1) with an
961                  * invalid ref.
962                  *
963                  * It's likely an error, but we need to find out if
964                  * we should auto-create the branch, case (3).(b).
965                  */
966                 int recover_with_dwim = dwim_new_local_branch_ok;
967
968                 if (!has_dash_dash &&
969                     (check_filename(opts->prefix, arg) || !no_wildcard(arg)))
970                         recover_with_dwim = 0;
971                 /*
972                  * Accept "git checkout foo" and "git checkout foo --"
973                  * as candidates for dwim.
974                  */
975                 if (!(argc == 1 && !has_dash_dash) &&
976                     !(argc == 2 && has_dash_dash))
977                         recover_with_dwim = 0;
978
979                 if (recover_with_dwim) {
980                         const char *remote = unique_tracking_name(arg, rev,
981                                                                   dwim_remotes_matched);
982                         if (remote) {
983                                 *new_branch = arg;
984                                 arg = remote;
985                                 /* DWIMmed to create local branch, case (3).(b) */
986                         } else {
987                                 recover_with_dwim = 0;
988                         }
989                 }
990
991                 if (!recover_with_dwim) {
992                         if (has_dash_dash)
993                                 die(_("invalid reference: %s"), arg);
994                         return argcount;
995                 }
996         }
997
998         /* we can't end up being in (2) anymore, eat the argument */
999         argcount++;
1000         argv++;
1001         argc--;
1002
1003         new_branch_info->name = arg;
1004         setup_branch_path(new_branch_info);
1005
1006         if (!check_refname_format(new_branch_info->path, 0) &&
1007             !read_ref(new_branch_info->path, &branch_rev))
1008                 oidcpy(rev, &branch_rev);
1009         else
1010                 new_branch_info->path = NULL; /* not an existing branch */
1011
1012         new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
1013         if (!new_branch_info->commit) {
1014                 /* not a commit */
1015                 *source_tree = parse_tree_indirect(rev);
1016         } else {
1017                 parse_commit_or_die(new_branch_info->commit);
1018                 *source_tree = get_commit_tree(new_branch_info->commit);
1019         }
1020
1021         if (!*source_tree)                   /* case (1): want a tree */
1022                 die(_("reference is not a tree: %s"), arg);
1023         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1024                 /*
1025                  * Do not complain the most common case
1026                  *      git checkout branch
1027                  * even if there happen to be a file called 'branch';
1028                  * it would be extremely annoying.
1029                  */
1030                 if (argc)
1031                         verify_non_filename(opts->prefix, arg);
1032         } else {
1033                 argcount++;
1034                 argv++;
1035                 argc--;
1036         }
1037
1038         return argcount;
1039 }
1040
1041 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1042 {
1043         int status;
1044         struct strbuf branch_ref = STRBUF_INIT;
1045
1046         if (!opts->new_branch)
1047                 die(_("You are on a branch yet to be born"));
1048         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1049         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1050         strbuf_release(&branch_ref);
1051         if (!opts->quiet)
1052                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1053                         opts->new_branch);
1054         return status;
1055 }
1056
1057 static int checkout_branch(struct checkout_opts *opts,
1058                            struct branch_info *new_branch_info)
1059 {
1060         if (opts->pathspec.nr)
1061                 die(_("paths cannot be used with switching branches"));
1062
1063         if (opts->patch_mode)
1064                 die(_("'%s' cannot be used with switching branches"),
1065                     "--patch");
1066
1067         if (opts->writeout_stage)
1068                 die(_("'%s' cannot be used with switching branches"),
1069                     "--ours/--theirs");
1070
1071         if (opts->force && opts->merge)
1072                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1073
1074         if (opts->force_detach && opts->new_branch)
1075                 die(_("'%s' cannot be used with '%s'"),
1076                     "--detach", "-b/-B/--orphan");
1077
1078         if (opts->new_orphan_branch) {
1079                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1080                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1081         } else if (opts->force_detach) {
1082                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1083                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1084         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1085                 opts->track = git_branch_track;
1086
1087         if (new_branch_info->name && !new_branch_info->commit)
1088                 die(_("Cannot switch branch to a non-commit '%s'"),
1089                     new_branch_info->name);
1090
1091         if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
1092             !opts->ignore_other_worktrees) {
1093                 int flag;
1094                 char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
1095                 if (head_ref &&
1096                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path)))
1097                         die_if_checked_out(new_branch_info->path, 1);
1098                 free(head_ref);
1099         }
1100
1101         if (!new_branch_info->commit && opts->new_branch) {
1102                 struct object_id rev;
1103                 int flag;
1104
1105                 if (!read_ref_full("HEAD", 0, &rev, &flag) &&
1106                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1107                         return switch_unborn_to_new_branch(opts);
1108         }
1109         return switch_branches(opts, new_branch_info);
1110 }
1111
1112 int cmd_checkout(int argc, const char **argv, const char *prefix)
1113 {
1114         struct checkout_opts opts;
1115         struct branch_info new_branch_info;
1116         char *conflict_style = NULL;
1117         int dwim_new_local_branch = 1;
1118         int dwim_remotes_matched = 0;
1119         struct option options[] = {
1120                 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1121                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1122                            N_("create and checkout a new branch")),
1123                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1124                            N_("create/reset and checkout a branch")),
1125                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1126                 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1127                 OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
1128                         BRANCH_TRACK_EXPLICIT),
1129                 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1130                 OPT_SET_INT_F('2', "ours", &opts.writeout_stage,
1131                               N_("checkout our version for unmerged files"),
1132                               2, PARSE_OPT_NONEG),
1133                 OPT_SET_INT_F('3', "theirs", &opts.writeout_stage,
1134                               N_("checkout their version for unmerged files"),
1135                               3, PARSE_OPT_NONEG),
1136                 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)"),
1137                            PARSE_OPT_NOCOMPLETE),
1138                 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1139                 OPT_BOOL_F(0, "overwrite-ignore", &opts.overwrite_ignore,
1140                            N_("update ignored files (default)"),
1141                            PARSE_OPT_NOCOMPLETE),
1142                 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1143                            N_("conflict style (merge or diff3)")),
1144                 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1145                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1146                          N_("do not limit pathspecs to sparse entries only")),
1147                 OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
1148                                 N_("second guess 'git checkout <no-such-branch>'")),
1149                 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1150                          N_("do not check if another worktree is holding the given ref")),
1151                 { OPTION_CALLBACK, 0, "recurse-submodules", NULL,
1152                             "checkout", "control recursive updating of submodules",
1153                             PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
1154                 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1155                 OPT_END(),
1156         };
1157
1158         memset(&opts, 0, sizeof(opts));
1159         memset(&new_branch_info, 0, sizeof(new_branch_info));
1160         opts.overwrite_ignore = 1;
1161         opts.prefix = prefix;
1162         opts.show_progress = -1;
1163
1164         git_config(git_checkout_config, &opts);
1165
1166         opts.track = BRANCH_TRACK_UNSPECIFIED;
1167
1168         argc = parse_options(argc, argv, prefix, options, checkout_usage,
1169                              PARSE_OPT_KEEP_DASHDASH);
1170
1171         if (opts.show_progress < 0) {
1172                 if (opts.quiet)
1173                         opts.show_progress = 0;
1174                 else
1175                         opts.show_progress = isatty(2);
1176         }
1177
1178         if (conflict_style) {
1179                 opts.merge = 1; /* implied */
1180                 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1181         }
1182
1183         if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1184                 die(_("-b, -B and --orphan are mutually exclusive"));
1185
1186         /*
1187          * From here on, new_branch will contain the branch to be checked out,
1188          * and new_branch_force and new_orphan_branch will tell us which one of
1189          * -b/-B/--orphan is being used.
1190          */
1191         if (opts.new_branch_force)
1192                 opts.new_branch = opts.new_branch_force;
1193
1194         if (opts.new_orphan_branch)
1195                 opts.new_branch = opts.new_orphan_branch;
1196
1197         /* --track without -b/-B/--orphan should DWIM */
1198         if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1199                 const char *argv0 = argv[0];
1200                 if (!argc || !strcmp(argv0, "--"))
1201                         die(_("--track needs a branch name"));
1202                 skip_prefix(argv0, "refs/", &argv0);
1203                 skip_prefix(argv0, "remotes/", &argv0);
1204                 argv0 = strchr(argv0, '/');
1205                 if (!argv0 || !argv0[1])
1206                         die(_("missing branch name; try -b"));
1207                 opts.new_branch = argv0 + 1;
1208         }
1209
1210         /*
1211          * Extract branch name from command line arguments, so
1212          * all that is left is pathspecs.
1213          *
1214          * Handle
1215          *
1216          *  1) git checkout <tree> -- [<paths>]
1217          *  2) git checkout -- [<paths>]
1218          *  3) git checkout <something> [<paths>]
1219          *
1220          * including "last branch" syntax and DWIM-ery for names of
1221          * remote branches, erroring out for invalid or ambiguous cases.
1222          */
1223         if (argc) {
1224                 struct object_id rev;
1225                 int dwim_ok =
1226                         !opts.patch_mode &&
1227                         dwim_new_local_branch &&
1228                         opts.track == BRANCH_TRACK_UNSPECIFIED &&
1229                         !opts.new_branch;
1230                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1231                                              &new_branch_info, &opts, &rev,
1232                                              &dwim_remotes_matched);
1233                 argv += n;
1234                 argc -= n;
1235         }
1236
1237         if (argc) {
1238                 parse_pathspec(&opts.pathspec, 0,
1239                                opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1240                                prefix, argv);
1241
1242                 if (!opts.pathspec.nr)
1243                         die(_("invalid path specification"));
1244
1245                 /*
1246                  * Try to give more helpful suggestion.
1247                  * new_branch && argc > 1 will be caught later.
1248                  */
1249                 if (opts.new_branch && argc == 1)
1250                         die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1251                                 argv[0], opts.new_branch);
1252
1253                 if (opts.force_detach)
1254                         die(_("git checkout: --detach does not take a path argument '%s'"),
1255                             argv[0]);
1256
1257                 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1258                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1259                               "checking out of the index."));
1260         }
1261
1262         if (opts.new_branch) {
1263                 struct strbuf buf = STRBUF_INIT;
1264
1265                 if (opts.new_branch_force)
1266                         opts.branch_exists = validate_branchname(opts.new_branch, &buf);
1267                 else
1268                         opts.branch_exists =
1269                                 validate_new_branchname(opts.new_branch, &buf, 0);
1270                 strbuf_release(&buf);
1271         }
1272
1273         UNLEAK(opts);
1274         if (opts.patch_mode || opts.pathspec.nr) {
1275                 int ret = checkout_paths(&opts, new_branch_info.name);
1276                 if (ret && dwim_remotes_matched > 1 &&
1277                     advice_checkout_ambiguous_remote_branch_name)
1278                         advise(_("'%s' matched more than one remote tracking branch.\n"
1279                                  "We found %d remotes with a reference that matched. So we fell back\n"
1280                                  "on trying to resolve the argument as a path, but failed there too!\n"
1281                                  "\n"
1282                                  "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
1283                                  "you can do so by fully qualifying the name with the --track option:\n"
1284                                  "\n"
1285                                  "    git checkout --track origin/<name>\n"
1286                                  "\n"
1287                                  "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
1288                                  "one remote, e.g. the 'origin' remote, consider setting\n"
1289                                  "checkout.defaultRemote=origin in your config."),
1290                                argv[0],
1291                                dwim_remotes_matched);
1292                 return ret;
1293         } else {
1294                 return checkout_branch(&opts, &new_branch_info);
1295         }
1296 }