builtin-mailinfo.c: check error status from rewind and ftruncate
[git/spearce.git] / builtin-checkout.c
blobd050c3789fcdaf1b50c12a20c28cbeaf774048eb
1 #include "cache.h"
2 #include "builtin.h"
3 #include "parse-options.h"
4 #include "refs.h"
5 #include "commit.h"
6 #include "tree.h"
7 #include "tree-walk.h"
8 #include "cache-tree.h"
9 #include "unpack-trees.h"
10 #include "dir.h"
11 #include "run-command.h"
12 #include "merge-recursive.h"
13 #include "branch.h"
14 #include "diff.h"
15 #include "revision.h"
16 #include "remote.h"
17 #include "blob.h"
18 #include "xdiff-interface.h"
19 #include "ll-merge.h"
21 static const char * const checkout_usage[] = {
22 "git checkout [options] <branch>",
23 "git checkout [options] [<branch>] -- <file>...",
24 NULL,
27 struct checkout_opts {
28 int quiet;
29 int merge;
30 int force;
31 int writeout_stage;
32 int writeout_error;
34 const char *new_branch;
35 int new_branch_log;
36 enum branch_track track;
39 static int post_checkout_hook(struct commit *old, struct commit *new,
40 int changed)
42 return run_hook(NULL, "post-checkout",
43 sha1_to_hex(old ? old->object.sha1 : null_sha1),
44 sha1_to_hex(new ? new->object.sha1 : null_sha1),
45 changed ? "1" : "0", NULL);
46 /* "new" can be NULL when checking out from the index before
47 a commit exists. */
51 static int update_some(const unsigned char *sha1, const char *base, int baselen,
52 const char *pathname, unsigned mode, int stage, void *context)
54 int len;
55 struct cache_entry *ce;
57 if (S_ISDIR(mode))
58 return READ_TREE_RECURSIVE;
60 len = baselen + strlen(pathname);
61 ce = xcalloc(1, cache_entry_size(len));
62 hashcpy(ce->sha1, sha1);
63 memcpy(ce->name, base, baselen);
64 memcpy(ce->name + baselen, pathname, len - baselen);
65 ce->ce_flags = create_ce_flags(len, 0);
66 ce->ce_mode = create_ce_mode(mode);
67 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
68 return 0;
71 static int read_tree_some(struct tree *tree, const char **pathspec)
73 read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
75 /* update the index with the given tree's info
76 * for all args, expanding wildcards, and exit
77 * with any non-zero return code.
79 return 0;
82 static int skip_same_name(struct cache_entry *ce, int pos)
84 while (++pos < active_nr &&
85 !strcmp(active_cache[pos]->name, ce->name))
86 ; /* skip */
87 return pos;
90 static int check_stage(int stage, struct cache_entry *ce, int pos)
92 while (pos < active_nr &&
93 !strcmp(active_cache[pos]->name, ce->name)) {
94 if (ce_stage(active_cache[pos]) == stage)
95 return 0;
96 pos++;
98 return error("path '%s' does not have %s version",
99 ce->name,
100 (stage == 2) ? "our" : "their");
103 static int check_all_stages(struct cache_entry *ce, int pos)
105 if (ce_stage(ce) != 1 ||
106 active_nr <= pos + 2 ||
107 strcmp(active_cache[pos+1]->name, ce->name) ||
108 ce_stage(active_cache[pos+1]) != 2 ||
109 strcmp(active_cache[pos+2]->name, ce->name) ||
110 ce_stage(active_cache[pos+2]) != 3)
111 return error("path '%s' does not have all three versions",
112 ce->name);
113 return 0;
116 static int checkout_stage(int stage, struct cache_entry *ce, int pos,
117 struct checkout *state)
119 while (pos < active_nr &&
120 !strcmp(active_cache[pos]->name, ce->name)) {
121 if (ce_stage(active_cache[pos]) == stage)
122 return checkout_entry(active_cache[pos], state, NULL);
123 pos++;
125 return error("path '%s' does not have %s version",
126 ce->name,
127 (stage == 2) ? "our" : "their");
130 /* NEEDSWORK: share with merge-recursive */
131 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
133 unsigned long size;
134 enum object_type type;
136 if (!hashcmp(sha1, null_sha1)) {
137 mm->ptr = xstrdup("");
138 mm->size = 0;
139 return;
142 mm->ptr = read_sha1_file(sha1, &type, &size);
143 if (!mm->ptr || type != OBJ_BLOB)
144 die("unable to read blob object %s", sha1_to_hex(sha1));
145 mm->size = size;
148 static int checkout_merged(int pos, struct checkout *state)
150 struct cache_entry *ce = active_cache[pos];
151 const char *path = ce->name;
152 mmfile_t ancestor, ours, theirs;
153 int status;
154 unsigned char sha1[20];
155 mmbuffer_t result_buf;
157 if (ce_stage(ce) != 1 ||
158 active_nr <= pos + 2 ||
159 strcmp(active_cache[pos+1]->name, path) ||
160 ce_stage(active_cache[pos+1]) != 2 ||
161 strcmp(active_cache[pos+2]->name, path) ||
162 ce_stage(active_cache[pos+2]) != 3)
163 return error("path '%s' does not have all 3 versions", path);
165 fill_mm(active_cache[pos]->sha1, &ancestor);
166 fill_mm(active_cache[pos+1]->sha1, &ours);
167 fill_mm(active_cache[pos+2]->sha1, &theirs);
169 status = ll_merge(&result_buf, path, &ancestor,
170 &ours, "ours", &theirs, "theirs", 1);
171 free(ancestor.ptr);
172 free(ours.ptr);
173 free(theirs.ptr);
174 if (status < 0 || !result_buf.ptr) {
175 free(result_buf.ptr);
176 return error("path '%s': cannot merge", path);
180 * NEEDSWORK:
181 * There is absolutely no reason to write this as a blob object
182 * and create a phony cache entry just to leak. This hack is
183 * primarily to get to the write_entry() machinery that massages
184 * the contents to work-tree format and writes out which only
185 * allows it for a cache entry. The code in write_entry() needs
186 * to be refactored to allow us to feed a <buffer, size, mode>
187 * instead of a cache entry. Such a refactoring would help
188 * merge_recursive as well (it also writes the merge result to the
189 * object database even when it may contain conflicts).
191 if (write_sha1_file(result_buf.ptr, result_buf.size,
192 blob_type, sha1))
193 die("Unable to add merge result for '%s'", path);
194 ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
195 sha1,
196 path, 2, 0);
197 if (!ce)
198 die("make_cache_entry failed for path '%s'", path);
199 status = checkout_entry(ce, state, NULL);
200 return status;
203 static int checkout_paths(struct tree *source_tree, const char **pathspec,
204 struct checkout_opts *opts)
206 int pos;
207 struct checkout state;
208 static char *ps_matched;
209 unsigned char rev[20];
210 int flag;
211 struct commit *head;
212 int errs = 0;
213 int stage = opts->writeout_stage;
214 int merge = opts->merge;
215 int newfd;
216 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
218 newfd = hold_locked_index(lock_file, 1);
219 if (read_cache_preload(pathspec) < 0)
220 return error("corrupt index file");
222 if (source_tree)
223 read_tree_some(source_tree, pathspec);
225 for (pos = 0; pathspec[pos]; pos++)
227 ps_matched = xcalloc(1, pos);
229 for (pos = 0; pos < active_nr; pos++) {
230 struct cache_entry *ce = active_cache[pos];
231 match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, ps_matched);
234 if (report_path_error(ps_matched, pathspec, 0))
235 return 1;
237 /* Any unmerged paths? */
238 for (pos = 0; pos < active_nr; pos++) {
239 struct cache_entry *ce = active_cache[pos];
240 if (match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, NULL)) {
241 if (!ce_stage(ce))
242 continue;
243 if (opts->force) {
244 warning("path '%s' is unmerged", ce->name);
245 } else if (stage) {
246 errs |= check_stage(stage, ce, pos);
247 } else if (opts->merge) {
248 errs |= check_all_stages(ce, pos);
249 } else {
250 errs = 1;
251 error("path '%s' is unmerged", ce->name);
253 pos = skip_same_name(ce, pos) - 1;
256 if (errs)
257 return 1;
259 /* Now we are committed to check them out */
260 memset(&state, 0, sizeof(state));
261 state.force = 1;
262 state.refresh_cache = 1;
263 for (pos = 0; pos < active_nr; pos++) {
264 struct cache_entry *ce = active_cache[pos];
265 if (match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, NULL)) {
266 if (!ce_stage(ce)) {
267 errs |= checkout_entry(ce, &state, NULL);
268 continue;
270 if (stage)
271 errs |= checkout_stage(stage, ce, pos, &state);
272 else if (merge)
273 errs |= checkout_merged(pos, &state);
274 pos = skip_same_name(ce, pos) - 1;
278 if (write_cache(newfd, active_cache, active_nr) ||
279 commit_locked_index(lock_file))
280 die("unable to write new index file");
282 resolve_ref("HEAD", rev, 0, &flag);
283 head = lookup_commit_reference_gently(rev, 1);
285 errs |= post_checkout_hook(head, head, 0);
286 return errs;
289 static void show_local_changes(struct object *head)
291 struct rev_info rev;
292 /* I think we want full paths, even if we're in a subdirectory. */
293 init_revisions(&rev, NULL);
294 rev.abbrev = 0;
295 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
296 if (diff_setup_done(&rev.diffopt) < 0)
297 die("diff_setup_done failed");
298 add_pending_object(&rev, head, NULL);
299 run_diff_index(&rev, 0);
302 static void describe_detached_head(char *msg, struct commit *commit)
304 struct strbuf sb = STRBUF_INIT;
305 parse_commit(commit);
306 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
307 fprintf(stderr, "%s %s... %s\n", msg,
308 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
309 strbuf_release(&sb);
312 static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
314 struct unpack_trees_options opts;
315 struct tree_desc tree_desc;
317 memset(&opts, 0, sizeof(opts));
318 opts.head_idx = -1;
319 opts.update = worktree;
320 opts.skip_unmerged = !worktree;
321 opts.reset = 1;
322 opts.merge = 1;
323 opts.fn = oneway_merge;
324 opts.verbose_update = !o->quiet;
325 opts.src_index = &the_index;
326 opts.dst_index = &the_index;
327 parse_tree(tree);
328 init_tree_desc(&tree_desc, tree->buffer, tree->size);
329 switch (unpack_trees(1, &tree_desc, &opts)) {
330 case -2:
331 o->writeout_error = 1;
333 * We return 0 nevertheless, as the index is all right
334 * and more importantly we have made best efforts to
335 * update paths in the work tree, and we cannot revert
336 * them.
338 case 0:
339 return 0;
340 default:
341 return 128;
345 struct branch_info {
346 const char *name; /* The short name used */
347 const char *path; /* The full name of a real branch */
348 struct commit *commit; /* The named commit */
351 static void setup_branch_path(struct branch_info *branch)
353 struct strbuf buf = STRBUF_INIT;
355 strbuf_branchname(&buf, branch->name);
356 if (strcmp(buf.buf, branch->name))
357 branch->name = xstrdup(buf.buf);
358 strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
359 branch->path = strbuf_detach(&buf, NULL);
362 static int merge_working_tree(struct checkout_opts *opts,
363 struct branch_info *old, struct branch_info *new)
365 int ret;
366 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
367 int newfd = hold_locked_index(lock_file, 1);
369 if (read_cache_preload(NULL) < 0)
370 return error("corrupt index file");
372 if (opts->force) {
373 ret = reset_tree(new->commit->tree, opts, 1);
374 if (ret)
375 return ret;
376 } else {
377 struct tree_desc trees[2];
378 struct tree *tree;
379 struct unpack_trees_options topts;
381 memset(&topts, 0, sizeof(topts));
382 topts.head_idx = -1;
383 topts.src_index = &the_index;
384 topts.dst_index = &the_index;
386 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
388 refresh_cache(REFRESH_QUIET);
390 if (unmerged_cache()) {
391 error("you need to resolve your current index first");
392 return 1;
395 /* 2-way merge to the new branch */
396 topts.initial_checkout = is_cache_unborn();
397 topts.update = 1;
398 topts.merge = 1;
399 topts.gently = opts->merge;
400 topts.verbose_update = !opts->quiet;
401 topts.fn = twoway_merge;
402 topts.dir = xcalloc(1, sizeof(*topts.dir));
403 topts.dir->flags |= DIR_SHOW_IGNORED;
404 topts.dir->exclude_per_dir = ".gitignore";
405 tree = parse_tree_indirect(old->commit ?
406 old->commit->object.sha1 :
407 (unsigned char *)EMPTY_TREE_SHA1_BIN);
408 init_tree_desc(&trees[0], tree->buffer, tree->size);
409 tree = parse_tree_indirect(new->commit->object.sha1);
410 init_tree_desc(&trees[1], tree->buffer, tree->size);
412 ret = unpack_trees(2, trees, &topts);
413 if (ret == -1) {
415 * Unpack couldn't do a trivial merge; either
416 * give up or do a real merge, depending on
417 * whether the merge flag was used.
419 struct tree *result;
420 struct tree *work;
421 struct merge_options o;
422 if (!opts->merge)
423 return 1;
424 parse_commit(old->commit);
426 /* Do more real merge */
429 * We update the index fully, then write the
430 * tree from the index, then merge the new
431 * branch with the current tree, with the old
432 * branch as the base. Then we reset the index
433 * (but not the working tree) to the new
434 * branch, leaving the working tree as the
435 * merged version, but skipping unmerged
436 * entries in the index.
439 add_files_to_cache(NULL, NULL, 0);
440 init_merge_options(&o);
441 o.verbosity = 0;
442 work = write_tree_from_memory(&o);
444 ret = reset_tree(new->commit->tree, opts, 1);
445 if (ret)
446 return ret;
447 o.branch1 = new->name;
448 o.branch2 = "local";
449 merge_trees(&o, new->commit->tree, work,
450 old->commit->tree, &result);
451 ret = reset_tree(new->commit->tree, opts, 0);
452 if (ret)
453 return ret;
457 if (write_cache(newfd, active_cache, active_nr) ||
458 commit_locked_index(lock_file))
459 die("unable to write new index file");
461 if (!opts->force && !opts->quiet)
462 show_local_changes(&new->commit->object);
464 return 0;
467 static void report_tracking(struct branch_info *new)
469 struct strbuf sb = STRBUF_INIT;
470 struct branch *branch = branch_get(new->name);
472 if (!format_tracking_info(branch, &sb))
473 return;
474 fputs(sb.buf, stdout);
475 strbuf_release(&sb);
478 static void update_refs_for_switch(struct checkout_opts *opts,
479 struct branch_info *old,
480 struct branch_info *new)
482 struct strbuf msg = STRBUF_INIT;
483 const char *old_desc;
484 if (opts->new_branch) {
485 create_branch(old->name, opts->new_branch, new->name, 0,
486 opts->new_branch_log, opts->track);
487 new->name = opts->new_branch;
488 setup_branch_path(new);
491 old_desc = old->name;
492 if (!old_desc && old->commit)
493 old_desc = sha1_to_hex(old->commit->object.sha1);
494 strbuf_addf(&msg, "checkout: moving from %s to %s",
495 old_desc ? old_desc : "(invalid)", new->name);
497 if (new->path) {
498 create_symref("HEAD", new->path, msg.buf);
499 if (!opts->quiet) {
500 if (old->path && !strcmp(new->path, old->path))
501 fprintf(stderr, "Already on '%s'\n",
502 new->name);
503 else
504 fprintf(stderr, "Switched to%s branch '%s'\n",
505 opts->new_branch ? " a new" : "",
506 new->name);
508 } else if (strcmp(new->name, "HEAD")) {
509 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
510 REF_NODEREF, DIE_ON_ERR);
511 if (!opts->quiet) {
512 if (old->path)
513 fprintf(stderr, "Note: moving to '%s' which isn't a local branch\nIf you want to create a new branch from this checkout, you may do so\n(now or later) by using -b with the checkout command again. Example:\n git checkout -b <new_branch_name>\n", new->name);
514 describe_detached_head("HEAD is now at", new->commit);
517 remove_branch_state();
518 strbuf_release(&msg);
519 if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
520 report_tracking(new);
523 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
525 int ret = 0;
526 struct branch_info old;
527 unsigned char rev[20];
528 int flag;
529 memset(&old, 0, sizeof(old));
530 old.path = resolve_ref("HEAD", rev, 0, &flag);
531 old.commit = lookup_commit_reference_gently(rev, 1);
532 if (!(flag & REF_ISSYMREF))
533 old.path = NULL;
535 if (old.path && !prefixcmp(old.path, "refs/heads/"))
536 old.name = old.path + strlen("refs/heads/");
538 if (!new->name) {
539 new->name = "HEAD";
540 new->commit = old.commit;
541 if (!new->commit)
542 die("You are on a branch yet to be born");
543 parse_commit(new->commit);
546 ret = merge_working_tree(opts, &old, new);
547 if (ret)
548 return ret;
551 * If we were on a detached HEAD, but have now moved to
552 * a new commit, we want to mention the old commit once more
553 * to remind the user that it might be lost.
555 if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
556 describe_detached_head("Previous HEAD position was", old.commit);
558 update_refs_for_switch(opts, &old, new);
560 ret = post_checkout_hook(old.commit, new->commit, 1);
561 return ret || opts->writeout_error;
564 static int git_checkout_config(const char *var, const char *value, void *cb)
566 return git_xmerge_config(var, value, cb);
569 static int interactive_checkout(const char *revision, const char **pathspec,
570 struct checkout_opts *opts)
572 return run_add_interactive(revision, "--patch=checkout", pathspec);
576 int cmd_checkout(int argc, const char **argv, const char *prefix)
578 struct checkout_opts opts;
579 unsigned char rev[20];
580 const char *arg;
581 struct branch_info new;
582 struct tree *source_tree = NULL;
583 char *conflict_style = NULL;
584 int patch_mode = 0;
585 struct option options[] = {
586 OPT__QUIET(&opts.quiet),
587 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
588 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
589 OPT_SET_INT('t', "track", &opts.track, "track",
590 BRANCH_TRACK_EXPLICIT),
591 OPT_SET_INT('2', "ours", &opts.writeout_stage, "stage",
593 OPT_SET_INT('3', "theirs", &opts.writeout_stage, "stage",
595 OPT_BOOLEAN('f', "force", &opts.force, "force"),
596 OPT_BOOLEAN('m', "merge", &opts.merge, "merge"),
597 OPT_STRING(0, "conflict", &conflict_style, "style",
598 "conflict style (merge or diff3)"),
599 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
600 OPT_END(),
602 int has_dash_dash;
604 memset(&opts, 0, sizeof(opts));
605 memset(&new, 0, sizeof(new));
607 git_config(git_checkout_config, NULL);
609 opts.track = BRANCH_TRACK_UNSPECIFIED;
611 argc = parse_options(argc, argv, prefix, options, checkout_usage,
612 PARSE_OPT_KEEP_DASHDASH);
614 if (patch_mode && (opts.track > 0 || opts.new_branch
615 || opts.new_branch_log || opts.merge || opts.force))
616 die ("--patch is incompatible with all other options");
618 /* --track without -b should DWIM */
619 if (0 < opts.track && !opts.new_branch) {
620 const char *argv0 = argv[0];
621 if (!argc || !strcmp(argv0, "--"))
622 die ("--track needs a branch name");
623 if (!prefixcmp(argv0, "refs/"))
624 argv0 += 5;
625 if (!prefixcmp(argv0, "remotes/"))
626 argv0 += 8;
627 argv0 = strchr(argv0, '/');
628 if (!argv0 || !argv0[1])
629 die ("Missing branch name; try -b");
630 opts.new_branch = argv0 + 1;
633 if (opts.track == BRANCH_TRACK_UNSPECIFIED)
634 opts.track = git_branch_track;
635 if (conflict_style) {
636 opts.merge = 1; /* implied */
637 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
640 if (opts.force && opts.merge)
641 die("git checkout: -f and -m are incompatible");
644 * case 1: git checkout <ref> -- [<paths>]
646 * <ref> must be a valid tree, everything after the '--' must be
647 * a path.
649 * case 2: git checkout -- [<paths>]
651 * everything after the '--' must be paths.
653 * case 3: git checkout <something> [<paths>]
655 * With no paths, if <something> is a commit, that is to
656 * switch to the branch or detach HEAD at it.
658 * Otherwise <something> shall not be ambiguous.
659 * - If it's *only* a reference, treat it like case (1).
660 * - If it's only a path, treat it like case (2).
661 * - else: fail.
664 if (argc) {
665 if (!strcmp(argv[0], "--")) { /* case (2) */
666 argv++;
667 argc--;
668 goto no_reference;
671 arg = argv[0];
672 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
674 if (!strcmp(arg, "-"))
675 arg = "@{-1}";
677 if (get_sha1(arg, rev)) {
678 if (has_dash_dash) /* case (1) */
679 die("invalid reference: %s", arg);
680 goto no_reference; /* case (3 -> 2) */
683 /* we can't end up being in (2) anymore, eat the argument */
684 argv++;
685 argc--;
687 new.name = arg;
688 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
689 setup_branch_path(&new);
690 if (resolve_ref(new.path, rev, 1, NULL))
691 new.commit = lookup_commit_reference(rev);
692 else
693 new.path = NULL;
694 parse_commit(new.commit);
695 source_tree = new.commit->tree;
696 } else
697 source_tree = parse_tree_indirect(rev);
699 if (!source_tree) /* case (1): want a tree */
700 die("reference is not a tree: %s", arg);
701 if (!has_dash_dash) {/* case (3 -> 1) */
703 * Do not complain the most common case
704 * git checkout branch
705 * even if there happen to be a file called 'branch';
706 * it would be extremely annoying.
708 if (argc)
709 verify_non_filename(NULL, arg);
711 else {
712 argv++;
713 argc--;
717 no_reference:
718 if (argc) {
719 const char **pathspec = get_pathspec(prefix, argv);
721 if (!pathspec)
722 die("invalid path specification");
724 if (patch_mode)
725 return interactive_checkout(new.name, pathspec, &opts);
727 /* Checkout paths */
728 if (opts.new_branch) {
729 if (argc == 1) {
730 die("git checkout: updating paths is incompatible with switching branches.\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
731 } else {
732 die("git checkout: updating paths is incompatible with switching branches.");
736 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
737 die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");
739 return checkout_paths(source_tree, pathspec, &opts);
742 if (patch_mode)
743 return interactive_checkout(new.name, NULL, &opts);
745 if (opts.new_branch) {
746 struct strbuf buf = STRBUF_INIT;
747 if (strbuf_check_branch_ref(&buf, opts.new_branch))
748 die("git checkout: we do not like '%s' as a branch name.",
749 opts.new_branch);
750 if (!get_sha1(buf.buf, rev))
751 die("git checkout: branch %s already exists", opts.new_branch);
752 strbuf_release(&buf);
755 if (new.name && !new.commit) {
756 die("Cannot switch branch to a non-commit.");
758 if (opts.writeout_stage)
759 die("--ours/--theirs is incompatible with switching branches.");
761 return switch_branches(&opts, &new);