24b8593b938b67baf4a662f2463efdd35562873a
[git/git.git] / builtin / checkout.c
1 #define USE_THE_INDEX_COMPATIBILITY_MACROS
2 #include "builtin.h"
3 #include "config.h"
4 #include "checkout.h"
5 #include "lockfile.h"
6 #include "parse-options.h"
7 #include "refs.h"
8 #include "object-store.h"
9 #include "commit.h"
10 #include "tree.h"
11 #include "tree-walk.h"
12 #include "cache-tree.h"
13 #include "unpack-trees.h"
14 #include "dir.h"
15 #include "run-command.h"
16 #include "merge-recursive.h"
17 #include "branch.h"
18 #include "diff.h"
19 #include "revision.h"
20 #include "remote.h"
21 #include "blob.h"
22 #include "xdiff-interface.h"
23 #include "ll-merge.h"
24 #include "resolve-undo.h"
25 #include "submodule-config.h"
26 #include "submodule.h"
27 #include "advice.h"
28
29 static int checkout_optimize_new_branch;
30
31 static const char * const checkout_usage[] = {
32 N_("git checkout [<options>] <branch>"),
33 N_("git checkout [<options>] [<branch>] -- <file>..."),
34 NULL,
35 };
36
37 struct checkout_opts {
38 int patch_mode;
39 int quiet;
40 int merge;
41 int force;
42 int force_detach;
43 int writeout_stage;
44 int overwrite_ignore;
45 int ignore_skipworktree;
46 int ignore_other_worktrees;
47 int show_progress;
48 int count_checkout_paths;
49 /*
50 * If new checkout options are added, skip_merge_working_tree
51 * should be updated accordingly.
52 */
53
54 const char *new_branch;
55 const char *new_branch_force;
56 const char *new_orphan_branch;
57 int new_branch_log;
58 enum branch_track track;
59 struct diff_options diff_options;
60
61 int branch_exists;
62 const char *prefix;
63 struct pathspec pathspec;
64 struct tree *source_tree;
65 };
66
67 static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
68 int changed)
69 {
70 return run_hook_le(NULL, "post-checkout",
71 oid_to_hex(old_commit ? &old_commit->object.oid : &null_oid),
72 oid_to_hex(new_commit ? &new_commit->object.oid : &null_oid),
73 changed ? "1" : "0", NULL);
74 /* "new_commit" can be NULL when checking out from the index before
75 a commit exists. */
76
77 }
78
79 static int update_some(const struct object_id *oid, struct strbuf *base,
80 const char *pathname, unsigned mode, int stage, void *context)
81 {
82 int len;
83 struct cache_entry *ce;
84 int pos;
85
86 if (S_ISDIR(mode))
87 return READ_TREE_RECURSIVE;
88
89 len = base->len + strlen(pathname);
90 ce = make_empty_cache_entry(&the_index, len);
91 oidcpy(&ce->oid, oid);
92 memcpy(ce->name, base->buf, base->len);
93 memcpy(ce->name + base->len, pathname, len - base->len);
94 ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
95 ce->ce_namelen = len;
96 ce->ce_mode = create_ce_mode(mode);
97
98 /*
99 * If the entry is the same as the current index, we can leave the old
100 * entry in place. Whether it is UPTODATE or not, checkout_entry will
101 * do the right thing.
102 */
103 pos = cache_name_pos(ce->name, ce->ce_namelen);
104 if (pos >= 0) {
105 struct cache_entry *old = active_cache[pos];
106 if (ce->ce_mode == old->ce_mode &&
107 oideq(&ce->oid, &old->oid)) {
108 old->ce_flags |= CE_UPDATE;
109 discard_cache_entry(ce);
110 return 0;
111 }
112 }
113
114 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
115 return 0;
116 }
117
118 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
119 {
120 read_tree_recursive(the_repository, tree, "", 0, 0,
121 pathspec, update_some, NULL);
122
123 /* update the index with the given tree's info
124 * for all args, expanding wildcards, and exit
125 * with any non-zero return code.
126 */
127 return 0;
128 }
129
130 static int skip_same_name(const struct cache_entry *ce, int pos)
131 {
132 while (++pos < active_nr &&
133 !strcmp(active_cache[pos]->name, ce->name))
134 ; /* skip */
135 return pos;
136 }
137
138 static int check_stage(int stage, const struct cache_entry *ce, int pos)
139 {
140 while (pos < active_nr &&
141 !strcmp(active_cache[pos]->name, ce->name)) {
142 if (ce_stage(active_cache[pos]) == stage)
143 return 0;
144 pos++;
145 }
146 if (stage == 2)
147 return error(_("path '%s' does not have our version"), ce->name);
148 else
149 return error(_("path '%s' does not have their version"), ce->name);
150 }
151
152 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
153 {
154 unsigned seen = 0;
155 const char *name = ce->name;
156
157 while (pos < active_nr) {
158 ce = active_cache[pos];
159 if (strcmp(name, ce->name))
160 break;
161 seen |= (1 << ce_stage(ce));
162 pos++;
163 }
164 if ((stages & seen) != stages)
165 return error(_("path '%s' does not have all necessary versions"),
166 name);
167 return 0;
168 }
169
170 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
171 const struct checkout *state, int *nr_checkouts)
172 {
173 while (pos < active_nr &&
174 !strcmp(active_cache[pos]->name, ce->name)) {
175 if (ce_stage(active_cache[pos]) == stage)
176 return checkout_entry(active_cache[pos], state,
177 NULL, nr_checkouts);
178 pos++;
179 }
180 if (stage == 2)
181 return error(_("path '%s' does not have our version"), ce->name);
182 else
183 return error(_("path '%s' does not have their version"), ce->name);
184 }
185
186 static int checkout_merged(int pos, const struct checkout *state, int *nr_checkouts)
187 {
188 struct cache_entry *ce = active_cache[pos];
189 const char *path = ce->name;
190 mmfile_t ancestor, ours, theirs;
191 int status;
192 struct object_id oid;
193 mmbuffer_t result_buf;
194 struct object_id threeway[3];
195 unsigned mode = 0;
196
197 memset(threeway, 0, sizeof(threeway));
198 while (pos < active_nr) {
199 int stage;
200 stage = ce_stage(ce);
201 if (!stage || strcmp(path, ce->name))
202 break;
203 oidcpy(&threeway[stage - 1], &ce->oid);
204 if (stage == 2)
205 mode = create_ce_mode(ce->ce_mode);
206 pos++;
207 ce = active_cache[pos];
208 }
209 if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
210 return error(_("path '%s' does not have necessary versions"), path);
211
212 read_mmblob(&ancestor, &threeway[0]);
213 read_mmblob(&ours, &threeway[1]);
214 read_mmblob(&theirs, &threeway[2]);
215
216 /*
217 * NEEDSWORK: re-create conflicts from merges with
218 * merge.renormalize set, too
219 */
220 status = ll_merge(&result_buf, path, &ancestor, "base",
221 &ours, "ours", &theirs, "theirs",
222 state->istate, NULL);
223 free(ancestor.ptr);
224 free(ours.ptr);
225 free(theirs.ptr);
226 if (status < 0 || !result_buf.ptr) {
227 free(result_buf.ptr);
228 return error(_("path '%s': cannot merge"), path);
229 }
230
231 /*
232 * NEEDSWORK:
233 * There is absolutely no reason to write this as a blob object
234 * and create a phony cache entry. This hack is primarily to get
235 * to the write_entry() machinery that massages the contents to
236 * work-tree format and writes out which only allows it for a
237 * cache entry. The code in write_entry() needs to be refactored
238 * to allow us to feed a <buffer, size, mode> instead of a cache
239 * entry. Such a refactoring would help merge_recursive as well
240 * (it also writes the merge result to the object database even
241 * when it may contain conflicts).
242 */
243 if (write_object_file(result_buf.ptr, result_buf.size, blob_type, &oid))
244 die(_("Unable to add merge result for '%s'"), path);
245 free(result_buf.ptr);
246 ce = make_transient_cache_entry(mode, &oid, path, 2);
247 if (!ce)
248 die(_("make_cache_entry failed for path '%s'"), path);
249 status = checkout_entry(ce, state, NULL, nr_checkouts);
250 discard_cache_entry(ce);
251 return status;
252 }
253
254 static int checkout_paths(const struct checkout_opts *opts,
255 const char *revision)
256 {
257 int pos;
258 struct checkout state = CHECKOUT_INIT;
259 static char *ps_matched;
260 struct object_id rev;
261 struct commit *head;
262 int errs = 0;
263 struct lock_file lock_file = LOCK_INIT;
264 int nr_checkouts = 0, nr_unmerged = 0;
265
266 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
267 die(_("'%s' cannot be used with updating paths"), "--track");
268
269 if (opts->new_branch_log)
270 die(_("'%s' cannot be used with updating paths"), "-l");
271
272 if (opts->force && opts->patch_mode)
273 die(_("'%s' cannot be used with updating paths"), "-f");
274
275 if (opts->force_detach)
276 die(_("'%s' cannot be used with updating paths"), "--detach");
277
278 if (opts->merge && opts->patch_mode)
279 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
280
281 if (opts->force && opts->merge)
282 die(_("'%s' cannot be used with %s"), "-f", "-m");
283
284 if (opts->new_branch)
285 die(_("Cannot update paths and switch to branch '%s' at the same time."),
286 opts->new_branch);
287
288 if (opts->patch_mode)
289 return run_add_interactive(revision, "--patch=checkout",
290 &opts->pathspec);
291
292 repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);
293 if (read_cache_preload(&opts->pathspec) < 0)
294 return error(_("index file corrupt"));
295
296 if (opts->source_tree)
297 read_tree_some(opts->source_tree, &opts->pathspec);
298
299 ps_matched = xcalloc(opts->pathspec.nr, 1);
300
301 /*
302 * Make sure all pathspecs participated in locating the paths
303 * to be checked out.
304 */
305 for (pos = 0; pos < active_nr; pos++) {
306 struct cache_entry *ce = active_cache[pos];
307 ce->ce_flags &= ~CE_MATCHED;
308 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
309 continue;
310 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
311 /*
312 * "git checkout tree-ish -- path", but this entry
313 * is in the original index; it will not be checked
314 * out to the working tree and it does not matter
315 * if pathspec matched this entry. We will not do
316 * anything to this entry at all.
317 */
318 continue;
319 /*
320 * Either this entry came from the tree-ish we are
321 * checking the paths out of, or we are checking out
322 * of the index.
323 *
324 * If it comes from the tree-ish, we already know it
325 * matches the pathspec and could just stamp
326 * CE_MATCHED to it from update_some(). But we still
327 * need ps_matched and read_tree_recursive (and
328 * eventually tree_entry_interesting) cannot fill
329 * ps_matched yet. Once it can, we can avoid calling
330 * match_pathspec() for _all_ entries when
331 * opts->source_tree != NULL.
332 */
333 if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched))
334 ce->ce_flags |= CE_MATCHED;
335 }
336
337 if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
338 free(ps_matched);
339 return 1;
340 }
341 free(ps_matched);
342
343 /* "checkout -m path" to recreate conflicted state */
344 if (opts->merge)
345 unmerge_marked_index(&the_index);
346
347 /* Any unmerged paths? */
348 for (pos = 0; pos < active_nr; pos++) {
349 const struct cache_entry *ce = active_cache[pos];
350 if (ce->ce_flags & CE_MATCHED) {
351 if (!ce_stage(ce))
352 continue;
353 if (opts->force) {
354 warning(_("path '%s' is unmerged"), ce->name);
355 } else if (opts->writeout_stage) {
356 errs |= check_stage(opts->writeout_stage, ce, pos);
357 } else if (opts->merge) {
358 errs |= check_stages((1<<2) | (1<<3), ce, pos);
359 } else {
360 errs = 1;
361 error(_("path '%s' is unmerged"), ce->name);
362 }
363 pos = skip_same_name(ce, pos) - 1;
364 }
365 }
366 if (errs)
367 return 1;
368
369 /* Now we are committed to check them out */
370 state.force = 1;
371 state.refresh_cache = 1;
372 state.istate = &the_index;
373
374 enable_delayed_checkout(&state);
375 for (pos = 0; pos < active_nr; pos++) {
376 struct cache_entry *ce = active_cache[pos];
377 if (ce->ce_flags & CE_MATCHED) {
378 if (!ce_stage(ce)) {
379 errs |= checkout_entry(ce, &state,
380 NULL, &nr_checkouts);
381 continue;
382 }
383 if (opts->writeout_stage)
384 errs |= checkout_stage(opts->writeout_stage,
385 ce, pos,
386 &state, &nr_checkouts);
387 else if (opts->merge)
388 errs |= checkout_merged(pos, &state,
389 &nr_unmerged);
390 pos = skip_same_name(ce, pos) - 1;
391 }
392 }
393 errs |= finish_delayed_checkout(&state, &nr_checkouts);
394
395 if (opts->count_checkout_paths) {
396 if (nr_unmerged)
397 fprintf_ln(stderr, Q_("Recreated %d merge conflict",
398 "Recreated %d merge conflicts",
399 nr_unmerged),
400 nr_unmerged);
401 if (opts->source_tree)
402 fprintf_ln(stderr, Q_("Updated %d path from %s",
403 "Updated %d paths from %s",
404 nr_checkouts),
405 nr_checkouts,
406 find_unique_abbrev(&opts->source_tree->object.oid,
407 DEFAULT_ABBREV));
408 else if (!nr_unmerged || nr_checkouts)
409 fprintf_ln(stderr, Q_("Updated %d path from the index",
410 "Updated %d paths from the index",
411 nr_checkouts),
412 nr_checkouts);
413 }
414
415 if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
416 die(_("unable to write new index file"));
417
418 read_ref_full("HEAD", 0, &rev, NULL);
419 head = lookup_commit_reference_gently(the_repository, &rev, 1);
420
421 errs |= post_checkout_hook(head, head, 0);
422 return errs;
423 }
424
425 static void show_local_changes(struct object *head,
426 const struct diff_options *opts)
427 {
428 struct rev_info rev;
429 /* I think we want full paths, even if we're in a subdirectory. */
430 repo_init_revisions(the_repository, &rev, NULL);
431 rev.diffopt.flags = opts->flags;
432 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
433 diff_setup_done(&rev.diffopt);
434 add_pending_object(&rev, head, NULL);
435 run_diff_index(&rev, 0);
436 }
437
438 static void describe_detached_head(const char *msg, struct commit *commit)
439 {
440 struct strbuf sb = STRBUF_INIT;
441
442 if (!parse_commit(commit))
443 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
444 if (print_sha1_ellipsis()) {
445 fprintf(stderr, "%s %s... %s\n", msg,
446 find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
447 } else {
448 fprintf(stderr, "%s %s %s\n", msg,
449 find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
450 }
451 strbuf_release(&sb);
452 }
453
454 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
455 int worktree, int *writeout_error)
456 {
457 struct unpack_trees_options opts;
458 struct tree_desc tree_desc;
459
460 memset(&opts, 0, sizeof(opts));
461 opts.head_idx = -1;
462 opts.update = worktree;
463 opts.skip_unmerged = !worktree;
464 opts.reset = 1;
465 opts.merge = 1;
466 opts.fn = oneway_merge;
467 opts.verbose_update = o->show_progress;
468 opts.src_index = &the_index;
469 opts.dst_index = &the_index;
470 parse_tree(tree);
471 init_tree_desc(&tree_desc, tree->buffer, tree->size);
472 switch (unpack_trees(1, &tree_desc, &opts)) {
473 case -2:
474 *writeout_error = 1;
475 /*
476 * We return 0 nevertheless, as the index is all right
477 * and more importantly we have made best efforts to
478 * update paths in the work tree, and we cannot revert
479 * them.
480 */
481 /* fallthrough */
482 case 0:
483 return 0;
484 default:
485 return 128;
486 }
487 }
488
489 struct branch_info {
490 const char *name; /* The short name used */
491 const char *path; /* The full name of a real branch */
492 struct commit *commit; /* The named commit */
493 /*
494 * if not null the branch is detached because it's already
495 * checked out in this checkout
496 */
497 char *checkout;
498 };
499
500 static void setup_branch_path(struct branch_info *branch)
501 {
502 struct strbuf buf = STRBUF_INIT;
503
504 strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
505 if (strcmp(buf.buf, branch->name))
506 branch->name = xstrdup(buf.buf);
507 strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
508 branch->path = strbuf_detach(&buf, NULL);
509 }
510
511 /*
512 * Skip merging the trees, updating the index and working directory if and
513 * only if we are creating a new branch via "git checkout -b <new_branch>."
514 */
515 static int skip_merge_working_tree(const struct checkout_opts *opts,
516 const struct branch_info *old_branch_info,
517 const struct branch_info *new_branch_info)
518 {
519 /*
520 * Do the merge if sparse checkout is on and the user has not opted in
521 * to the optimized behavior
522 */
523 if (core_apply_sparse_checkout && !checkout_optimize_new_branch)
524 return 0;
525
526 /*
527 * We must do the merge if we are actually moving to a new commit.
528 */
529 if (!old_branch_info->commit || !new_branch_info->commit ||
530 !oideq(&old_branch_info->commit->object.oid,
531 &new_branch_info->commit->object.oid))
532 return 0;
533
534 /*
535 * opts->patch_mode cannot be used with switching branches so is
536 * not tested here
537 */
538
539 /*
540 * opts->quiet only impacts output so doesn't require a merge
541 */
542
543 /*
544 * Honor the explicit request for a three-way merge or to throw away
545 * local changes
546 */
547 if (opts->merge || opts->force)
548 return 0;
549
550 /*
551 * --detach is documented as "updating the index and the files in the
552 * working tree" but this optimization skips those steps so fall through
553 * to the regular code path.
554 */
555 if (opts->force_detach)
556 return 0;
557
558 /*
559 * opts->writeout_stage cannot be used with switching branches so is
560 * not tested here
561 */
562
563 /*
564 * Honor the explicit ignore requests
565 */
566 if (!opts->overwrite_ignore || opts->ignore_skipworktree ||
567 opts->ignore_other_worktrees)
568 return 0;
569
570 /*
571 * opts->show_progress only impacts output so doesn't require a merge
572 */
573
574 /*
575 * If we aren't creating a new branch any changes or updates will
576 * happen in the existing branch. Since that could only be updating
577 * the index and working directory, we don't want to skip those steps
578 * or we've defeated any purpose in running the command.
579 */
580 if (!opts->new_branch)
581 return 0;
582
583 /*
584 * new_branch_force is defined to "create/reset and checkout a branch"
585 * so needs to go through the merge to do the reset
586 */
587 if (opts->new_branch_force)
588 return 0;
589
590 /*
591 * A new orphaned branch requrires the index and the working tree to be
592 * adjusted to <start_point>
593 */
594 if (opts->new_orphan_branch)
595 return 0;
596
597 /*
598 * Remaining variables are not checkout options but used to track state
599 */
600
601 /*
602 * Do the merge if this is the initial checkout. We cannot use
603 * is_cache_unborn() here because the index hasn't been loaded yet
604 * so cache_nr and timestamp.sec are always zero.
605 */
606 if (!file_exists(get_index_file()))
607 return 0;
608
609 return 1;
610 }
611
612 static int merge_working_tree(const struct checkout_opts *opts,
613 struct branch_info *old_branch_info,
614 struct branch_info *new_branch_info,
615 int *writeout_error)
616 {
617 int ret;
618 struct lock_file lock_file = LOCK_INIT;
619
620 hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
621 if (read_cache_preload(NULL) < 0)
622 return error(_("index file corrupt"));
623
624 resolve_undo_clear();
625 if (opts->force) {
626 ret = reset_tree(get_commit_tree(new_branch_info->commit),
627 opts, 1, writeout_error);
628 if (ret)
629 return ret;
630 } else {
631 struct tree_desc trees[2];
632 struct tree *tree;
633 struct unpack_trees_options topts;
634
635 memset(&topts, 0, sizeof(topts));
636 topts.head_idx = -1;
637 topts.src_index = &the_index;
638 topts.dst_index = &the_index;
639
640 setup_unpack_trees_porcelain(&topts, "checkout");
641
642 refresh_cache(REFRESH_QUIET);
643
644 if (unmerged_cache()) {
645 error(_("you need to resolve your current index first"));
646 return 1;
647 }
648
649 /* 2-way merge to the new branch */
650 topts.initial_checkout = is_cache_unborn();
651 topts.update = 1;
652 topts.merge = 1;
653 topts.gently = opts->merge && old_branch_info->commit;
654 topts.verbose_update = opts->show_progress;
655 topts.fn = twoway_merge;
656 if (opts->overwrite_ignore) {
657 topts.dir = xcalloc(1, sizeof(*topts.dir));
658 topts.dir->flags |= DIR_SHOW_IGNORED;
659 setup_standard_excludes(topts.dir);
660 }
661 tree = parse_tree_indirect(old_branch_info->commit ?
662 &old_branch_info->commit->object.oid :
663 the_hash_algo->empty_tree);
664 init_tree_desc(&trees[0], tree->buffer, tree->size);
665 tree = parse_tree_indirect(&new_branch_info->commit->object.oid);
666 init_tree_desc(&trees[1], tree->buffer, tree->size);
667
668 ret = unpack_trees(2, trees, &topts);
669 clear_unpack_trees_porcelain(&topts);
670 if (ret == -1) {
671 /*
672 * Unpack couldn't do a trivial merge; either
673 * give up or do a real merge, depending on
674 * whether the merge flag was used.
675 */
676 struct tree *result;
677 struct tree *work;
678 struct merge_options o;
679 if (!opts->merge)
680 return 1;
681
682 /*
683 * Without old_branch_info->commit, the below is the same as
684 * the two-tree unpack we already tried and failed.
685 */
686 if (!old_branch_info->commit)
687 return 1;
688
689 /* Do more real merge */
690
691 /*
692 * We update the index fully, then write the
693 * tree from the index, then merge the new
694 * branch with the current tree, with the old
695 * branch as the base. Then we reset the index
696 * (but not the working tree) to the new
697 * branch, leaving the working tree as the
698 * merged version, but skipping unmerged
699 * entries in the index.
700 */
701
702 add_files_to_cache(NULL, NULL, 0);
703 /*
704 * NEEDSWORK: carrying over local changes
705 * when branches have different end-of-line
706 * normalization (or clean+smudge rules) is
707 * a pain; plumb in an option to set
708 * o.renormalize?
709 */
710 init_merge_options(&o, the_repository);
711 o.verbosity = 0;
712 work = write_tree_from_memory(&o);
713
714 ret = reset_tree(get_commit_tree(new_branch_info->commit),
715 opts, 1,
716 writeout_error);
717 if (ret)
718 return ret;
719 o.ancestor = old_branch_info->name;
720 o.branch1 = new_branch_info->name;
721 o.branch2 = "local";
722 ret = merge_trees(&o,
723 get_commit_tree(new_branch_info->commit),
724 work,
725 get_commit_tree(old_branch_info->commit),
726 &result);
727 if (ret < 0)
728 exit(128);
729 ret = reset_tree(get_commit_tree(new_branch_info->commit),
730 opts, 0,
731 writeout_error);
732 strbuf_release(&o.obuf);
733 if (ret)
734 return ret;
735 }
736 }
737
738 if (!active_cache_tree)
739 active_cache_tree = cache_tree();
740
741 if (!cache_tree_fully_valid(active_cache_tree))
742 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
743
744 if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
745 die(_("unable to write new index file"));
746
747 if (!opts->force && !opts->quiet)
748 show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
749
750 return 0;
751 }
752
753 static void report_tracking(struct branch_info *new_branch_info)
754 {
755 struct strbuf sb = STRBUF_INIT;
756 struct branch *branch = branch_get(new_branch_info->name);
757
758 if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL))
759 return;
760 fputs(sb.buf, stdout);
761 strbuf_release(&sb);
762 }
763
764 static void update_refs_for_switch(const struct checkout_opts *opts,
765 struct branch_info *old_branch_info,
766 struct branch_info *new_branch_info)
767 {
768 struct strbuf msg = STRBUF_INIT;
769 const char *old_desc, *reflog_msg;
770 if (opts->new_branch) {
771 if (opts->new_orphan_branch) {
772 char *refname;
773
774 refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
775 if (opts->new_branch_log &&
776 !should_autocreate_reflog(refname)) {
777 int ret;
778 struct strbuf err = STRBUF_INIT;
779
780 ret = safe_create_reflog(refname, 1, &err);
781 if (ret) {
782 fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
783 opts->new_orphan_branch, err.buf);
784 strbuf_release(&err);
785 free(refname);
786 return;
787 }
788 strbuf_release(&err);
789 }
790 free(refname);
791 }
792 else
793 create_branch(the_repository,
794 opts->new_branch, new_branch_info->name,
795 opts->new_branch_force ? 1 : 0,
796 opts->new_branch_force ? 1 : 0,
797 opts->new_branch_log,
798 opts->quiet,
799 opts->track);
800 new_branch_info->name = opts->new_branch;
801 setup_branch_path(new_branch_info);
802 }
803
804 old_desc = old_branch_info->name;
805 if (!old_desc && old_branch_info->commit)
806 old_desc = oid_to_hex(&old_branch_info->commit->object.oid);
807
808 reflog_msg = getenv("GIT_REFLOG_ACTION");
809 if (!reflog_msg)
810 strbuf_addf(&msg, "checkout: moving from %s to %s",
811 old_desc ? old_desc : "(invalid)", new_branch_info->name);
812 else
813 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
814
815 if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
816 /* Nothing to do. */
817 } else if (opts->force_detach || !new_branch_info->path) { /* No longer on any branch. */
818 update_ref(msg.buf, "HEAD", &new_branch_info->commit->object.oid, NULL,
819 REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
820 if (!opts->quiet) {
821 if (old_branch_info->path &&
822 advice_detached_head && !opts->force_detach)
823 detach_advice(new_branch_info->name);
824 describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
825 }
826 } else if (new_branch_info->path) { /* Switch branches. */
827 if (create_symref("HEAD", new_branch_info->path, msg.buf) < 0)
828 die(_("unable to update HEAD"));
829 if (!opts->quiet) {
830 if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
831 if (opts->new_branch_force)
832 fprintf(stderr, _("Reset branch '%s'\n"),
833 new_branch_info->name);
834 else
835 fprintf(stderr, _("Already on '%s'\n"),
836 new_branch_info->name);
837 } else if (opts->new_branch) {
838 if (opts->branch_exists)
839 fprintf(stderr, _("Switched to and reset branch '%s'\n"), new_branch_info->name);
840 else
841 fprintf(stderr, _("Switched to a new branch '%s'\n"), new_branch_info->name);
842 } else {
843 fprintf(stderr, _("Switched to branch '%s'\n"),
844 new_branch_info->name);
845 }
846 }
847 if (old_branch_info->path && old_branch_info->name) {
848 if (!ref_exists(old_branch_info->path) && reflog_exists(old_branch_info->path))
849 delete_reflog(old_branch_info->path);
850 }
851 }
852 remove_branch_state(the_repository);
853 strbuf_release(&msg);
854 if (!opts->quiet &&
855 (new_branch_info->path || (!opts->force_detach && !strcmp(new_branch_info->name, "HEAD"))))
856 report_tracking(new_branch_info);
857 }
858
859 static int add_pending_uninteresting_ref(const char *refname,
860 const struct object_id *oid,
861 int flags, void *cb_data)
862 {
863 add_pending_oid(cb_data, refname, oid, UNINTERESTING);
864 return 0;
865 }
866
867 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
868 {
869 strbuf_addstr(sb, " ");
870 strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
871 strbuf_addch(sb, ' ');
872 if (!parse_commit(commit))
873 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
874 strbuf_addch(sb, '\n');
875 }
876
877 #define ORPHAN_CUTOFF 4
878 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
879 {
880 struct commit *c, *last = NULL;
881 struct strbuf sb = STRBUF_INIT;
882 int lost = 0;
883 while ((c = get_revision(revs)) != NULL) {
884 if (lost < ORPHAN_CUTOFF)
885 describe_one_orphan(&sb, c);
886 last = c;
887 lost++;
888 }
889 if (ORPHAN_CUTOFF < lost) {
890 int more = lost - ORPHAN_CUTOFF;
891 if (more == 1)
892 describe_one_orphan(&sb, last);
893 else
894 strbuf_addf(&sb, _(" ... and %d more.\n"), more);
895 }
896
897 fprintf(stderr,
898 Q_(
899 /* The singular version */
900 "Warning: you are leaving %d commit behind, "
901 "not connected to\n"
902 "any of your branches:\n\n"
903 "%s\n",
904 /* The plural version */
905 "Warning: you are leaving %d commits behind, "
906 "not connected to\n"
907 "any of your branches:\n\n"
908 "%s\n",
909 /* Give ngettext() the count */
910 lost),
911 lost,
912 sb.buf);
913 strbuf_release(&sb);
914
915 if (advice_detached_head)
916 fprintf(stderr,
917 Q_(
918 /* The singular version */
919 "If you want to keep it by creating a new branch, "
920 "this may be a good time\nto do so with:\n\n"
921 " git branch <new-branch-name> %s\n\n",
922 /* The plural version */
923 "If you want to keep them by creating a new branch, "
924 "this may be a good time\nto do so with:\n\n"
925 " git branch <new-branch-name> %s\n\n",
926 /* Give ngettext() the count */
927 lost),
928 find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
929 }
930
931 /*
932 * We are about to leave commit that was at the tip of a detached
933 * HEAD. If it is not reachable from any ref, this is the last chance
934 * for the user to do so without resorting to reflog.
935 */
936 static void orphaned_commit_warning(struct commit *old_commit, struct commit *new_commit)
937 {
938 struct rev_info revs;
939 struct object *object = &old_commit->object;
940
941 repo_init_revisions(the_repository, &revs, NULL);
942 setup_revisions(0, NULL, &revs, NULL);
943
944 object->flags &= ~UNINTERESTING;
945 add_pending_object(&revs, object, oid_to_hex(&object->oid));
946
947 for_each_ref(add_pending_uninteresting_ref, &revs);
948 add_pending_oid(&revs, "HEAD", &new_commit->object.oid, UNINTERESTING);
949
950 if (prepare_revision_walk(&revs))
951 die(_("internal error in revision walk"));
952 if (!(old_commit->object.flags & UNINTERESTING))
953 suggest_reattach(old_commit, &revs);
954 else
955 describe_detached_head(_("Previous HEAD position was"), old_commit);
956
957 /* Clean up objects used, as they will be reused. */
958 clear_commit_marks_all(ALL_REV_FLAGS);
959 }
960
961 static int switch_branches(const struct checkout_opts *opts,
962 struct branch_info *new_branch_info)
963 {
964 int ret = 0;
965 struct branch_info old_branch_info;
966 void *path_to_free;
967 struct object_id rev;
968 int flag, writeout_error = 0;
969 memset(&old_branch_info, 0, sizeof(old_branch_info));
970 old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
971 if (old_branch_info.path)
972 old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
973 if (!(flag & REF_ISSYMREF))
974 old_branch_info.path = NULL;
975
976 if (old_branch_info.path)
977 skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
978
979 if (!new_branch_info->name) {
980 new_branch_info->name = "HEAD";
981 new_branch_info->commit = old_branch_info.commit;
982 if (!new_branch_info->commit)
983 die(_("You are on a branch yet to be born"));
984 parse_commit_or_die(new_branch_info->commit);
985 }
986
987 /* optimize the "checkout -b <new_branch> path */
988 if (skip_merge_working_tree(opts, &old_branch_info, new_branch_info)) {
989 if (!checkout_optimize_new_branch && !opts->quiet) {
990 if (read_cache_preload(NULL) < 0)
991 return error(_("index file corrupt"));
992 show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
993 }
994 } else {
995 ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error);
996 if (ret) {
997 free(path_to_free);
998 return ret;
999 }
1000 }
1001
1002 if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit)
1003 orphaned_commit_warning(old_branch_info.commit, new_branch_info->commit);
1004
1005 update_refs_for_switch(opts, &old_branch_info, new_branch_info);
1006
1007 ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
1008 free(path_to_free);
1009 return ret || writeout_error;
1010 }
1011
1012 static int git_checkout_config(const char *var, const char *value, void *cb)
1013 {
1014 if (!strcmp(var, "checkout.optimizenewbranch")) {
1015 checkout_optimize_new_branch = git_config_bool(var, value);
1016 return 0;
1017 }
1018
1019 if (!strcmp(var, "diff.ignoresubmodules")) {
1020 struct checkout_opts *opts = cb;
1021 handle_ignore_submodules_arg(&opts->diff_options, value);
1022 return 0;
1023 }
1024
1025 if (starts_with(var, "submodule."))
1026 return git_default_submodule_config(var, value, NULL);
1027
1028 return git_xmerge_config(var, value, NULL);
1029 }
1030
1031 static int parse_branchname_arg(int argc, const char **argv,
1032 int dwim_new_local_branch_ok,
1033 struct branch_info *new_branch_info,
1034 struct checkout_opts *opts,
1035 struct object_id *rev,
1036 int *dwim_remotes_matched)
1037 {
1038 struct tree **source_tree = &opts->source_tree;
1039 const char **new_branch = &opts->new_branch;
1040 int argcount = 0;
1041 struct object_id branch_rev;
1042 const char *arg;
1043 int dash_dash_pos;
1044 int has_dash_dash = 0;
1045 int i;
1046
1047 /*
1048 * case 1: git checkout <ref> -- [<paths>]
1049 *
1050 * <ref> must be a valid tree, everything after the '--' must be
1051 * a path.
1052 *
1053 * case 2: git checkout -- [<paths>]
1054 *
1055 * everything after the '--' must be paths.
1056 *
1057 * case 3: git checkout <something> [--]
1058 *
1059 * (a) If <something> is a commit, that is to
1060 * switch to the branch or detach HEAD at it. As a special case,
1061 * if <something> is A...B (missing A or B means HEAD but you can
1062 * omit at most one side), and if there is a unique merge base
1063 * between A and B, A...B names that merge base.
1064 *
1065 * (b) If <something> is _not_ a commit, either "--" is present
1066 * or <something> is not a path, no -t or -b was given, and
1067 * and there is a tracking branch whose name is <something>
1068 * in one and only one remote (or if the branch exists on the
1069 * remote named in checkout.defaultRemote), then this is a
1070 * short-hand to fork local <something> from that
1071 * remote-tracking branch.
1072 *
1073 * (c) Otherwise, if "--" is present, treat it like case (1).
1074 *
1075 * (d) Otherwise :
1076 * - if it's a reference, treat it like case (1)
1077 * - else if it's a path, treat it like case (2)
1078 * - else: fail.
1079 *
1080 * case 4: git checkout <something> <paths>
1081 *
1082 * The first argument must not be ambiguous.
1083 * - If it's *only* a reference, treat it like case (1).
1084 * - If it's only a path, treat it like case (2).
1085 * - else: fail.
1086 *
1087 */
1088 if (!argc)
1089 return 0;
1090
1091 arg = argv[0];
1092 dash_dash_pos = -1;
1093 for (i = 0; i < argc; i++) {
1094 if (!strcmp(argv[i], "--")) {
1095 dash_dash_pos = i;
1096 break;
1097 }
1098 }
1099 if (dash_dash_pos == 0)
1100 return 1; /* case (2) */
1101 else if (dash_dash_pos == 1)
1102 has_dash_dash = 1; /* case (3) or (1) */
1103 else if (dash_dash_pos >= 2)
1104 die(_("only one reference expected, %d given."), dash_dash_pos);
1105 opts->count_checkout_paths = !opts->quiet && !has_dash_dash;
1106
1107 if (!strcmp(arg, "-"))
1108 arg = "@{-1}";
1109
1110 if (get_oid_mb(arg, rev)) {
1111 /*
1112 * Either case (3) or (4), with <something> not being
1113 * a commit, or an attempt to use case (1) with an
1114 * invalid ref.
1115 *
1116 * It's likely an error, but we need to find out if
1117 * we should auto-create the branch, case (3).(b).
1118 */
1119 int recover_with_dwim = dwim_new_local_branch_ok;
1120
1121 int could_be_checkout_paths = !has_dash_dash &&
1122 check_filename(opts->prefix, arg);
1123
1124 if (!has_dash_dash && !no_wildcard(arg))
1125 recover_with_dwim = 0;
1126
1127 /*
1128 * Accept "git checkout foo" and "git checkout foo --"
1129 * as candidates for dwim.
1130 */
1131 if (!(argc == 1 && !has_dash_dash) &&
1132 !(argc == 2 && has_dash_dash))
1133 recover_with_dwim = 0;
1134
1135 if (recover_with_dwim) {
1136 const char *remote = unique_tracking_name(arg, rev,
1137 dwim_remotes_matched);
1138 if (remote) {
1139 if (could_be_checkout_paths)
1140 die(_("'%s' could be both a local file and a tracking branch.\n"
1141 "Please use -- (and optionally --no-guess) to disambiguate"),
1142 arg);
1143 *new_branch = arg;
1144 arg = remote;
1145 /* DWIMmed to create local branch, case (3).(b) */
1146 } else {
1147 recover_with_dwim = 0;
1148 }
1149 }
1150
1151 if (!recover_with_dwim) {
1152 if (has_dash_dash)
1153 die(_("invalid reference: %s"), arg);
1154 return argcount;
1155 }
1156 }
1157
1158 /* we can't end up being in (2) anymore, eat the argument */
1159 argcount++;
1160 argv++;
1161 argc--;
1162
1163 new_branch_info->name = arg;
1164 setup_branch_path(new_branch_info);
1165
1166 if (!check_refname_format(new_branch_info->path, 0) &&
1167 !read_ref(new_branch_info->path, &branch_rev))
1168 oidcpy(rev, &branch_rev);
1169 else
1170 new_branch_info->path = NULL; /* not an existing branch */
1171
1172 new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
1173 if (!new_branch_info->commit) {
1174 /* not a commit */
1175 *source_tree = parse_tree_indirect(rev);
1176 } else {
1177 parse_commit_or_die(new_branch_info->commit);
1178 *source_tree = get_commit_tree(new_branch_info->commit);
1179 }
1180
1181 if (!*source_tree) /* case (1): want a tree */
1182 die(_("reference is not a tree: %s"), arg);
1183 if (!has_dash_dash) { /* case (3).(d) -> (1) */
1184 /*
1185 * Do not complain the most common case
1186 * git checkout branch
1187 * even if there happen to be a file called 'branch';
1188 * it would be extremely annoying.
1189 */
1190 if (argc)
1191 verify_non_filename(opts->prefix, arg);
1192 } else {
1193 argcount++;
1194 argv++;
1195 argc--;
1196 }
1197
1198 return argcount;
1199 }
1200
1201 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1202 {
1203 int status;
1204 struct strbuf branch_ref = STRBUF_INIT;
1205
1206 if (!opts->new_branch)
1207 die(_("You are on a branch yet to be born"));
1208 strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1209 status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1210 strbuf_release(&branch_ref);
1211 if (!opts->quiet)
1212 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1213 opts->new_branch);
1214 return status;
1215 }
1216
1217 static int checkout_branch(struct checkout_opts *opts,
1218 struct branch_info *new_branch_info)
1219 {
1220 if (opts->pathspec.nr)
1221 die(_("paths cannot be used with switching branches"));
1222
1223 if (opts->patch_mode)
1224 die(_("'%s' cannot be used with switching branches"),
1225 "--patch");
1226
1227 if (opts->writeout_stage)
1228 die(_("'%s' cannot be used with switching branches"),
1229 "--ours/--theirs");
1230
1231 if (opts->force && opts->merge)
1232 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1233
1234 if (opts->force_detach && opts->new_branch)
1235 die(_("'%s' cannot be used with '%s'"),
1236 "--detach", "-b/-B/--orphan");
1237
1238 if (opts->new_orphan_branch) {
1239 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1240 die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1241 } else if (opts->force_detach) {
1242 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1243 die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1244 } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1245 opts->track = git_branch_track;
1246
1247 if (new_branch_info->name && !new_branch_info->commit)
1248 die(_("Cannot switch branch to a non-commit '%s'"),
1249 new_branch_info->name);
1250
1251 if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
1252 !opts->ignore_other_worktrees) {
1253 int flag;
1254 char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
1255 if (head_ref &&
1256 (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path)))
1257 die_if_checked_out(new_branch_info->path, 1);
1258 free(head_ref);
1259 }
1260
1261 if (!new_branch_info->commit && opts->new_branch) {
1262 struct object_id rev;
1263 int flag;
1264
1265 if (!read_ref_full("HEAD", 0, &rev, &flag) &&
1266 (flag & REF_ISSYMREF) && is_null_oid(&rev))
1267 return switch_unborn_to_new_branch(opts);
1268 }
1269 return switch_branches(opts, new_branch_info);
1270 }
1271
1272 int cmd_checkout(int argc, const char **argv, const char *prefix)
1273 {
1274 struct checkout_opts opts;
1275 struct branch_info new_branch_info;
1276 char *conflict_style = NULL;
1277 int dwim_new_local_branch, no_dwim_new_local_branch = 0;
1278 int dwim_remotes_matched = 0;
1279 struct option options[] = {
1280 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1281 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1282 N_("create and checkout a new branch")),
1283 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1284 N_("create/reset and checkout a branch")),
1285 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1286 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1287 OPT_SET_INT('t', "track", &opts.track, N_("set upstream info for new branch"),
1288 BRANCH_TRACK_EXPLICIT),
1289 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1290 OPT_SET_INT_F('2', "ours", &opts.writeout_stage,
1291 N_("checkout our version for unmerged files"),
1292 2, PARSE_OPT_NONEG),
1293 OPT_SET_INT_F('3', "theirs", &opts.writeout_stage,
1294 N_("checkout their version for unmerged files"),
1295 3, PARSE_OPT_NONEG),
1296 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)"),
1297 PARSE_OPT_NOCOMPLETE),
1298 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1299 OPT_BOOL_F(0, "overwrite-ignore", &opts.overwrite_ignore,
1300 N_("update ignored files (default)"),
1301 PARSE_OPT_NOCOMPLETE),
1302 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1303 N_("conflict style (merge or diff3)")),
1304 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1305 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1306 N_("do not limit pathspecs to sparse entries only")),
1307 OPT_BOOL(0, "no-guess", &no_dwim_new_local_branch,
1308 N_("do not second guess 'git checkout <no-such-branch>'")),
1309 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1310 N_("do not check if another worktree is holding the given ref")),
1311 { OPTION_CALLBACK, 0, "recurse-submodules", NULL,
1312 "checkout", "control recursive updating of submodules",
1313 PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
1314 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1315 OPT_END(),
1316 };
1317
1318 memset(&opts, 0, sizeof(opts));
1319 memset(&new_branch_info, 0, sizeof(new_branch_info));
1320 opts.overwrite_ignore = 1;
1321 opts.prefix = prefix;
1322 opts.show_progress = -1;
1323
1324 git_config(git_checkout_config, &opts);
1325
1326 opts.track = BRANCH_TRACK_UNSPECIFIED;
1327
1328 argc = parse_options(argc, argv, prefix, options, checkout_usage,
1329 PARSE_OPT_KEEP_DASHDASH);
1330
1331 dwim_new_local_branch = !no_dwim_new_local_branch;
1332 if (opts.show_progress < 0) {
1333 if (opts.quiet)
1334 opts.show_progress = 0;
1335 else
1336 opts.show_progress = isatty(2);
1337 }
1338
1339 if (conflict_style) {
1340 opts.merge = 1; /* implied */
1341 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1342 }
1343
1344 if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1345 die(_("-b, -B and --orphan are mutually exclusive"));
1346
1347 /*
1348 * From here on, new_branch will contain the branch to be checked out,
1349 * and new_branch_force and new_orphan_branch will tell us which one of
1350 * -b/-B/--orphan is being used.
1351 */
1352 if (opts.new_branch_force)
1353 opts.new_branch = opts.new_branch_force;
1354
1355 if (opts.new_orphan_branch)
1356 opts.new_branch = opts.new_orphan_branch;
1357
1358 /* --track without -b/-B/--orphan should DWIM */
1359 if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1360 const char *argv0 = argv[0];
1361 if (!argc || !strcmp(argv0, "--"))
1362 die(_("--track needs a branch name"));
1363 skip_prefix(argv0, "refs/", &argv0);
1364 skip_prefix(argv0, "remotes/", &argv0);
1365 argv0 = strchr(argv0, '/');
1366 if (!argv0 || !argv0[1])
1367 die(_("missing branch name; try -b"));
1368 opts.new_branch = argv0 + 1;
1369 }
1370
1371 /*
1372 * Extract branch name from command line arguments, so
1373 * all that is left is pathspecs.
1374 *
1375 * Handle
1376 *
1377 * 1) git checkout <tree> -- [<paths>]
1378 * 2) git checkout -- [<paths>]
1379 * 3) git checkout <something> [<paths>]
1380 *
1381 * including "last branch" syntax and DWIM-ery for names of
1382 * remote branches, erroring out for invalid or ambiguous cases.
1383 */
1384 if (argc) {
1385 struct object_id rev;
1386 int dwim_ok =
1387 !opts.patch_mode &&
1388 dwim_new_local_branch &&
1389 opts.track == BRANCH_TRACK_UNSPECIFIED &&
1390 !opts.new_branch;
1391 int n = parse_branchname_arg(argc, argv, dwim_ok,
1392 &new_branch_info, &opts, &rev,
1393 &dwim_remotes_matched);
1394 argv += n;
1395 argc -= n;
1396 }
1397
1398 if (argc) {
1399 parse_pathspec(&opts.pathspec, 0,
1400 opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1401 prefix, argv);
1402
1403 if (!opts.pathspec.nr)
1404 die(_("invalid path specification"));
1405
1406 /*
1407 * Try to give more helpful suggestion.
1408 * new_branch && argc > 1 will be caught later.
1409 */
1410 if (opts.new_branch && argc == 1)
1411 die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1412 argv[0], opts.new_branch);
1413
1414 if (opts.force_detach)
1415 die(_("git checkout: --detach does not take a path argument '%s'"),
1416 argv[0]);
1417
1418 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1419 die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1420 "checking out of the index."));
1421 }
1422
1423 if (opts.new_branch) {
1424 struct strbuf buf = STRBUF_INIT;
1425
1426 if (opts.new_branch_force)
1427 opts.branch_exists = validate_branchname(opts.new_branch, &buf);
1428 else
1429 opts.branch_exists =
1430 validate_new_branchname(opts.new_branch, &buf, 0);
1431 strbuf_release(&buf);
1432 }
1433
1434 UNLEAK(opts);
1435 if (opts.patch_mode || opts.pathspec.nr) {
1436 int ret = checkout_paths(&opts, new_branch_info.name);
1437 if (ret && dwim_remotes_matched > 1 &&
1438 advice_checkout_ambiguous_remote_branch_name)
1439 advise(_("'%s' matched more than one remote tracking branch.\n"
1440 "We found %d remotes with a reference that matched. So we fell back\n"
1441 "on trying to resolve the argument as a path, but failed there too!\n"
1442 "\n"
1443 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
1444 "you can do so by fully qualifying the name with the --track option:\n"
1445 "\n"
1446 " git checkout --track origin/<name>\n"
1447 "\n"
1448 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
1449 "one remote, e.g. the 'origin' remote, consider setting\n"
1450 "checkout.defaultRemote=origin in your config."),
1451 argv[0],
1452 dwim_remotes_matched);
1453 return ret;
1454 } else {
1455 return checkout_branch(&opts, &new_branch_info);
1456 }
1457 }