checkout: split off a function to peel away branchname arg
[git/git.git] / builtin / checkout.c
CommitLineData
782c2d65
DB
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"
b9d37a54 8#include "cache-tree.h"
782c2d65
DB
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"
79a1e6b4 16#include "remote.h"
0cf8581e
JH
17#include "blob.h"
18#include "xdiff-interface.h"
19#include "ll-merge.h"
cfc5789a 20#include "resolve-undo.h"
175f6e59 21#include "submodule.h"
782c2d65
DB
22
23static const char * const checkout_usage[] = {
24 "git checkout [options] <branch>",
25 "git checkout [options] [<branch>] -- <file>...",
26 NULL,
27};
28
db941099
JH
29struct checkout_opts {
30 int quiet;
31 int merge;
32 int force;
38901a48 33 int writeout_stage;
db941099
JH
34 int writeout_error;
35
02ac9837
TRC
36 /* not set by parse_options */
37 int branch_exists;
38
db941099 39 const char *new_branch;
02ac9837 40 const char *new_branch_force;
9db5ebf4 41 const char *new_orphan_branch;
db941099
JH
42 int new_branch_log;
43 enum branch_track track;
175f6e59 44 struct diff_options diff_options;
db941099
JH
45};
46
782c2d65
DB
47static int post_checkout_hook(struct commit *old, struct commit *new,
48 int changed)
49{
ae98a008
SB
50 return run_hook(NULL, "post-checkout",
51 sha1_to_hex(old ? old->object.sha1 : null_sha1),
52 sha1_to_hex(new ? new->object.sha1 : null_sha1),
53 changed ? "1" : "0", NULL);
2292ce47
SB
54 /* "new" can be NULL when checking out from the index before
55 a commit exists. */
ae98a008 56
782c2d65
DB
57}
58
59static int update_some(const unsigned char *sha1, const char *base, int baselen,
671f0707 60 const char *pathname, unsigned mode, int stage, void *context)
782c2d65
DB
61{
62 int len;
63 struct cache_entry *ce;
64
782c2d65
DB
65 if (S_ISDIR(mode))
66 return READ_TREE_RECURSIVE;
67
68 len = baselen + strlen(pathname);
69 ce = xcalloc(1, cache_entry_size(len));
70 hashcpy(ce->sha1, sha1);
71 memcpy(ce->name, base, baselen);
72 memcpy(ce->name + baselen, pathname, len - baselen);
73 ce->ce_flags = create_ce_flags(len, 0);
74 ce->ce_mode = create_ce_mode(mode);
75 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
76 return 0;
77}
78
79static int read_tree_some(struct tree *tree, const char **pathspec)
80{
671f0707 81 read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
782c2d65 82
782c2d65
DB
83 /* update the index with the given tree's info
84 * for all args, expanding wildcards, and exit
85 * with any non-zero return code.
86 */
87 return 0;
88}
89
8fdcf312
JH
90static int skip_same_name(struct cache_entry *ce, int pos)
91{
92 while (++pos < active_nr &&
93 !strcmp(active_cache[pos]->name, ce->name))
94 ; /* skip */
95 return pos;
96}
97
38901a48
JH
98static int check_stage(int stage, struct cache_entry *ce, int pos)
99{
100 while (pos < active_nr &&
101 !strcmp(active_cache[pos]->name, ce->name)) {
102 if (ce_stage(active_cache[pos]) == stage)
103 return 0;
104 pos++;
105 }
106 return error("path '%s' does not have %s version",
107 ce->name,
108 (stage == 2) ? "our" : "their");
109}
110
0cf8581e
JH
111static int check_all_stages(struct cache_entry *ce, int pos)
112{
113 if (ce_stage(ce) != 1 ||
114 active_nr <= pos + 2 ||
115 strcmp(active_cache[pos+1]->name, ce->name) ||
116 ce_stage(active_cache[pos+1]) != 2 ||
117 strcmp(active_cache[pos+2]->name, ce->name) ||
118 ce_stage(active_cache[pos+2]) != 3)
119 return error("path '%s' does not have all three versions",
120 ce->name);
121 return 0;
122}
123
38901a48
JH
124static int checkout_stage(int stage, struct cache_entry *ce, int pos,
125 struct checkout *state)
126{
127 while (pos < active_nr &&
128 !strcmp(active_cache[pos]->name, ce->name)) {
129 if (ce_stage(active_cache[pos]) == stage)
130 return checkout_entry(active_cache[pos], state, NULL);
131 pos++;
132 }
133 return error("path '%s' does not have %s version",
134 ce->name,
135 (stage == 2) ? "our" : "their");
136}
8fdcf312 137
0cf8581e
JH
138static int checkout_merged(int pos, struct checkout *state)
139{
140 struct cache_entry *ce = active_cache[pos];
141 const char *path = ce->name;
142 mmfile_t ancestor, ours, theirs;
143 int status;
144 unsigned char sha1[20];
145 mmbuffer_t result_buf;
146
147 if (ce_stage(ce) != 1 ||
148 active_nr <= pos + 2 ||
149 strcmp(active_cache[pos+1]->name, path) ||
150 ce_stage(active_cache[pos+1]) != 2 ||
151 strcmp(active_cache[pos+2]->name, path) ||
152 ce_stage(active_cache[pos+2]) != 3)
153 return error("path '%s' does not have all 3 versions", path);
154
06b65939
ML
155 read_mmblob(&ancestor, active_cache[pos]->sha1);
156 read_mmblob(&ours, active_cache[pos+1]->sha1);
157 read_mmblob(&theirs, active_cache[pos+2]->sha1);
0cf8581e 158
18b037a5
JN
159 /*
160 * NEEDSWORK: re-create conflicts from merges with
161 * merge.renormalize set, too
162 */
f0531a29 163 status = ll_merge(&result_buf, path, &ancestor, "base",
6d6f9acc 164 &ours, "ours", &theirs, "theirs", 0);
0cf8581e
JH
165 free(ancestor.ptr);
166 free(ours.ptr);
167 free(theirs.ptr);
168 if (status < 0 || !result_buf.ptr) {
169 free(result_buf.ptr);
170 return error("path '%s': cannot merge", path);
171 }
172
173 /*
174 * NEEDSWORK:
175 * There is absolutely no reason to write this as a blob object
3ea3c215 176 * and create a phony cache entry just to leak. This hack is
0cf8581e
JH
177 * primarily to get to the write_entry() machinery that massages
178 * the contents to work-tree format and writes out which only
179 * allows it for a cache entry. The code in write_entry() needs
180 * to be refactored to allow us to feed a <buffer, size, mode>
181 * instead of a cache entry. Such a refactoring would help
182 * merge_recursive as well (it also writes the merge result to the
183 * object database even when it may contain conflicts).
184 */
185 if (write_sha1_file(result_buf.ptr, result_buf.size,
186 blob_type, sha1))
187 die("Unable to add merge result for '%s'", path);
188 ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
189 sha1,
190 path, 2, 0);
048f2762
DP
191 if (!ce)
192 die("make_cache_entry failed for path '%s'", path);
0cf8581e
JH
193 status = checkout_entry(ce, state, NULL);
194 return status;
195}
8fdcf312 196
db941099
JH
197static int checkout_paths(struct tree *source_tree, const char **pathspec,
198 struct checkout_opts *opts)
782c2d65
DB
199{
200 int pos;
201 struct checkout state;
202 static char *ps_matched;
203 unsigned char rev[20];
204 int flag;
205 struct commit *head;
d2b3691b 206 int errs = 0;
38901a48 207 int stage = opts->writeout_stage;
0cf8581e 208 int merge = opts->merge;
75336878
DB
209 int newfd;
210 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
211
212 newfd = hold_locked_index(lock_file, 1);
53996fe5 213 if (read_cache_preload(pathspec) < 0)
b96524f8 214 return error("corrupt index file");
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DB
215
216 if (source_tree)
217 read_tree_some(source_tree, pathspec);
218
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DB
219 for (pos = 0; pathspec[pos]; pos++)
220 ;
221 ps_matched = xcalloc(1, pos);
222
223 for (pos = 0; pos < active_nr; pos++) {
224 struct cache_entry *ce = active_cache[pos];
0b50922a 225 match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, ps_matched);
782c2d65
DB
226 }
227
228 if (report_path_error(ps_matched, pathspec, 0))
229 return 1;
230
4421a823
JH
231 /* "checkout -m path" to recreate conflicted state */
232 if (opts->merge)
233 unmerge_cache(pathspec);
234
8fdcf312
JH
235 /* Any unmerged paths? */
236 for (pos = 0; pos < active_nr; pos++) {
237 struct cache_entry *ce = active_cache[pos];
0b50922a 238 if (match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, NULL)) {
8fdcf312
JH
239 if (!ce_stage(ce))
240 continue;
db941099
JH
241 if (opts->force) {
242 warning("path '%s' is unmerged", ce->name);
38901a48
JH
243 } else if (stage) {
244 errs |= check_stage(stage, ce, pos);
0cf8581e
JH
245 } else if (opts->merge) {
246 errs |= check_all_stages(ce, pos);
db941099
JH
247 } else {
248 errs = 1;
249 error("path '%s' is unmerged", ce->name);
250 }
8fdcf312
JH
251 pos = skip_same_name(ce, pos) - 1;
252 }
253 }
254 if (errs)
255 return 1;
256
d2b3691b 257 /* Now we are committed to check them out */
782c2d65
DB
258 memset(&state, 0, sizeof(state));
259 state.force = 1;
260 state.refresh_cache = 1;
261 for (pos = 0; pos < active_nr; pos++) {
262 struct cache_entry *ce = active_cache[pos];
0b50922a 263 if (match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, NULL)) {
8fdcf312
JH
264 if (!ce_stage(ce)) {
265 errs |= checkout_entry(ce, &state, NULL);
266 continue;
267 }
38901a48
JH
268 if (stage)
269 errs |= checkout_stage(stage, ce, pos, &state);
0cf8581e
JH
270 else if (merge)
271 errs |= checkout_merged(pos, &state);
8fdcf312 272 pos = skip_same_name(ce, pos) - 1;
782c2d65
DB
273 }
274 }
275
75336878
DB
276 if (write_cache(newfd, active_cache, active_nr) ||
277 commit_locked_index(lock_file))
278 die("unable to write new index file");
279
782c2d65
DB
280 resolve_ref("HEAD", rev, 0, &flag);
281 head = lookup_commit_reference_gently(rev, 1);
282
d2b3691b
JH
283 errs |= post_checkout_hook(head, head, 0);
284 return errs;
782c2d65
DB
285}
286
175f6e59 287static void show_local_changes(struct object *head, struct diff_options *opts)
782c2d65
DB
288{
289 struct rev_info rev;
290 /* I think we want full paths, even if we're in a subdirectory. */
291 init_revisions(&rev, NULL);
175f6e59 292 rev.diffopt.flags = opts->flags;
782c2d65 293 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
e752f4bb
KC
294 if (diff_setup_done(&rev.diffopt) < 0)
295 die("diff_setup_done failed");
782c2d65
DB
296 add_pending_object(&rev, head, NULL);
297 run_diff_index(&rev, 0);
298}
299
300static void describe_detached_head(char *msg, struct commit *commit)
301{
f285a2d7 302 struct strbuf sb = STRBUF_INIT;
dd2e794a 303 struct pretty_print_context ctx = {0};
782c2d65 304 parse_commit(commit);
dd2e794a 305 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, &ctx);
782c2d65
DB
306 fprintf(stderr, "%s %s... %s\n", msg,
307 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
308 strbuf_release(&sb);
309}
310
6286a08d 311static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
782c2d65
DB
312{
313 struct unpack_trees_options opts;
314 struct tree_desc tree_desc;
bc052d7f 315
782c2d65
DB
316 memset(&opts, 0, sizeof(opts));
317 opts.head_idx = -1;
6286a08d
JH
318 opts.update = worktree;
319 opts.skip_unmerged = !worktree;
782c2d65
DB
320 opts.reset = 1;
321 opts.merge = 1;
322 opts.fn = oneway_merge;
6286a08d 323 opts.verbose_update = !o->quiet;
34110cd4
LT
324 opts.src_index = &the_index;
325 opts.dst_index = &the_index;
782c2d65
DB
326 parse_tree(tree);
327 init_tree_desc(&tree_desc, tree->buffer, tree->size);
291d823e
JH
328 switch (unpack_trees(1, &tree_desc, &opts)) {
329 case -2:
330 o->writeout_error = 1;
331 /*
332 * We return 0 nevertheless, as the index is all right
333 * and more importantly we have made best efforts to
334 * update paths in the work tree, and we cannot revert
335 * them.
336 */
337 case 0:
338 return 0;
339 default:
84a5750b 340 return 128;
291d823e 341 }
782c2d65
DB
342}
343
782c2d65
DB
344struct branch_info {
345 const char *name; /* The short name used */
346 const char *path; /* The full name of a real branch */
347 struct commit *commit; /* The named commit */
348};
349
350static void setup_branch_path(struct branch_info *branch)
351{
f285a2d7 352 struct strbuf buf = STRBUF_INIT;
ae5a6c36 353
a552de75
JH
354 strbuf_branchname(&buf, branch->name);
355 if (strcmp(buf.buf, branch->name))
ae5a6c36 356 branch->name = xstrdup(buf.buf);
a552de75 357 strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
782c2d65
DB
358 branch->path = strbuf_detach(&buf, NULL);
359}
360
361static int merge_working_tree(struct checkout_opts *opts,
75ea38df 362 struct branch_info *old, struct branch_info *new)
782c2d65
DB
363{
364 int ret;
365 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
366 int newfd = hold_locked_index(lock_file, 1);
b96524f8 367
53996fe5 368 if (read_cache_preload(NULL) < 0)
b96524f8 369 return error("corrupt index file");
782c2d65 370
cfc5789a 371 resolve_undo_clear();
782c2d65 372 if (opts->force) {
6286a08d 373 ret = reset_tree(new->commit->tree, opts, 1);
782c2d65
DB
374 if (ret)
375 return ret;
376 } else {
377 struct tree_desc trees[2];
378 struct tree *tree;
379 struct unpack_trees_options topts;
bc052d7f 380
782c2d65
DB
381 memset(&topts, 0, sizeof(topts));
382 topts.head_idx = -1;
34110cd4
LT
383 topts.src_index = &the_index;
384 topts.dst_index = &the_index;
782c2d65 385
e294030f 386 setup_unpack_trees_porcelain(&topts, "checkout");
8ccba008 387
782c2d65
DB
388 refresh_cache(REFRESH_QUIET);
389
390 if (unmerged_cache()) {
04c9e11f
JH
391 error("you need to resolve your current index first");
392 return 1;
782c2d65 393 }
04c9e11f
JH
394
395 /* 2-way merge to the new branch */
fa7b3c2f 396 topts.initial_checkout = is_cache_unborn();
04c9e11f
JH
397 topts.update = 1;
398 topts.merge = 1;
64da3ae5 399 topts.gently = opts->merge && old->commit;
04c9e11f
JH
400 topts.verbose_update = !opts->quiet;
401 topts.fn = twoway_merge;
402 topts.dir = xcalloc(1, sizeof(*topts.dir));
7c4c97c0 403 topts.dir->flags |= DIR_SHOW_IGNORED;
04c9e11f 404 topts.dir->exclude_per_dir = ".gitignore";
cc580af8
JK
405 tree = parse_tree_indirect(old->commit ?
406 old->commit->object.sha1 :
407 (unsigned char *)EMPTY_TREE_SHA1_BIN);
04c9e11f
JH
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);
411
291d823e 412 ret = unpack_trees(2, trees, &topts);
49d833dc 413 if (ret == -1) {
782c2d65
DB
414 /*
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.
418 */
419 struct tree *result;
420 struct tree *work;
8a2fce18 421 struct merge_options o;
782c2d65
DB
422 if (!opts->merge)
423 return 1;
64da3ae5
JH
424
425 /*
426 * Without old->commit, the below is the same as
427 * the two-tree unpack we already tried and failed.
428 */
429 if (!old->commit)
430 return 1;
782c2d65
DB
431
432 /* Do more real merge */
433
434 /*
435 * We update the index fully, then write the
436 * tree from the index, then merge the new
437 * branch with the current tree, with the old
438 * branch as the base. Then we reset the index
439 * (but not the working tree) to the new
440 * branch, leaving the working tree as the
441 * merged version, but skipping unmerged
442 * entries in the index.
443 */
444
7ae02a30 445 add_files_to_cache(NULL, NULL, 0);
7610fa57
JN
446 /*
447 * NEEDSWORK: carrying over local changes
448 * when branches have different end-of-line
449 * normalization (or clean+smudge rules) is
450 * a pain; plumb in an option to set
451 * o.renormalize?
452 */
8a2fce18
MV
453 init_merge_options(&o);
454 o.verbosity = 0;
455 work = write_tree_from_memory(&o);
782c2d65 456
6286a08d 457 ret = reset_tree(new->commit->tree, opts, 1);
782c2d65
DB
458 if (ret)
459 return ret;
c4151629 460 o.ancestor = old->name;
8a2fce18
MV
461 o.branch1 = new->name;
462 o.branch2 = "local";
463 merge_trees(&o, new->commit->tree, work,
464 old->commit->tree, &result);
6286a08d 465 ret = reset_tree(new->commit->tree, opts, 0);
84a5750b
JH
466 if (ret)
467 return ret;
782c2d65
DB
468 }
469 }
470
471 if (write_cache(newfd, active_cache, active_nr) ||
472 commit_locked_index(lock_file))
473 die("unable to write new index file");
474
7fe4a728 475 if (!opts->force && !opts->quiet)
175f6e59 476 show_local_changes(&new->commit->object, &opts->diff_options);
782c2d65
DB
477
478 return 0;
479}
480
6d21bf96 481static void report_tracking(struct branch_info *new)
79a1e6b4 482{
6d21bf96 483 struct strbuf sb = STRBUF_INIT;
b56fca07 484 struct branch *branch = branch_get(new->name);
79a1e6b4 485
6d21bf96 486 if (!format_tracking_info(branch, &sb))
79a1e6b4 487 return;
6d21bf96
JH
488 fputs(sb.buf, stdout);
489 strbuf_release(&sb);
b0030db3 490}
79a1e6b4 491
13be3e31
JH
492static void detach_advice(const char *old_path, const char *new_name)
493{
494 const char fmt[] =
495 "Note: checking out '%s'.\n\n"
496 "You are in 'detached HEAD' state. You can look around, make experimental\n"
497 "changes and commit them, and you can discard any commits you make in this\n"
498 "state without impacting any branches by performing another checkout.\n\n"
499 "If you want to create a new branch to retain commits you create, you may\n"
500 "do so (now or later) by using -b with the checkout command again. Example:\n\n"
501 " git checkout -b new_branch_name\n\n";
502
503 fprintf(stderr, fmt, new_name);
504}
505
782c2d65
DB
506static void update_refs_for_switch(struct checkout_opts *opts,
507 struct branch_info *old,
508 struct branch_info *new)
509{
f285a2d7 510 struct strbuf msg = STRBUF_INIT;
782c2d65
DB
511 const char *old_desc;
512 if (opts->new_branch) {
3631bf77
EM
513 if (opts->new_orphan_branch) {
514 if (opts->new_branch_log && !log_all_ref_updates) {
515 int temp;
157aaea5 516 char log_file[PATH_MAX];
3631bf77
EM
517 char *ref_name = mkpath("refs/heads/%s", opts->new_orphan_branch);
518
519 temp = log_all_ref_updates;
520 log_all_ref_updates = 1;
157aaea5 521 if (log_ref_setup(ref_name, log_file, sizeof(log_file))) {
3631bf77
EM
522 fprintf(stderr, "Can not do reflog for '%s'\n",
523 opts->new_orphan_branch);
524 log_all_ref_updates = temp;
525 return;
526 }
527 log_all_ref_updates = temp;
528 }
529 }
530 else
02ac9837
TRC
531 create_branch(old->name, opts->new_branch, new->name,
532 opts->new_branch_force ? 1 : 0,
9db5ebf4 533 opts->new_branch_log, opts->track);
782c2d65
DB
534 new->name = opts->new_branch;
535 setup_branch_path(new);
536 }
537
782c2d65 538 old_desc = old->name;
323e00fd 539 if (!old_desc && old->commit)
782c2d65
DB
540 old_desc = sha1_to_hex(old->commit->object.sha1);
541 strbuf_addf(&msg, "checkout: moving from %s to %s",
323e00fd 542 old_desc ? old_desc : "(invalid)", new->name);
782c2d65
DB
543
544 if (new->path) {
545 create_symref("HEAD", new->path, msg.buf);
546 if (!opts->quiet) {
547 if (old->path && !strcmp(new->path, old->path))
714fddf2 548 fprintf(stderr, "Already on '%s'\n",
782c2d65 549 new->name);
09a0ec58 550 else if (opts->new_branch)
714fddf2 551 fprintf(stderr, "Switched to%s branch '%s'\n",
02ac9837 552 opts->branch_exists ? " and reset" : " a new",
782c2d65 553 new->name);
09a0ec58
RR
554 else
555 fprintf(stderr, "Switched to branch '%s'\n",
556 new->name);
782c2d65 557 }
3631bf77
EM
558 if (old->path && old->name) {
559 char log_file[PATH_MAX], ref_file[PATH_MAX];
560
561 git_snpath(log_file, sizeof(log_file), "logs/%s", old->path);
562 git_snpath(ref_file, sizeof(ref_file), "%s", old->path);
563 if (!file_exists(ref_file) && file_exists(log_file))
564 remove_path(log_file);
565 }
782c2d65
DB
566 } else if (strcmp(new->name, "HEAD")) {
567 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
568 REF_NODEREF, DIE_ON_ERR);
569 if (!opts->quiet) {
13be3e31
JH
570 if (old->path && advice_detached_head)
571 detach_advice(old->path, new->name);
782c2d65
DB
572 describe_detached_head("HEAD is now at", new->commit);
573 }
574 }
575 remove_branch_state();
576 strbuf_release(&msg);
b0030db3 577 if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
6d21bf96 578 report_tracking(new);
782c2d65
DB
579}
580
75ea38df 581static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
782c2d65
DB
582{
583 int ret = 0;
584 struct branch_info old;
585 unsigned char rev[20];
586 int flag;
587 memset(&old, 0, sizeof(old));
588 old.path = resolve_ref("HEAD", rev, 0, &flag);
589 old.commit = lookup_commit_reference_gently(rev, 1);
590 if (!(flag & REF_ISSYMREF))
591 old.path = NULL;
592
593 if (old.path && !prefixcmp(old.path, "refs/heads/"))
594 old.name = old.path + strlen("refs/heads/");
595
596 if (!new->name) {
597 new->name = "HEAD";
598 new->commit = old.commit;
599 if (!new->commit)
600 die("You are on a branch yet to be born");
601 parse_commit(new->commit);
602 }
603
75ea38df 604 ret = merge_working_tree(opts, &old, new);
782c2d65
DB
605 if (ret)
606 return ret;
607
77ebd56d
DC
608 /*
609 * If we were on a detached HEAD, but have now moved to
610 * a new commit, we want to mention the old commit once more
611 * to remind the user that it might be lost.
612 */
613 if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
614 describe_detached_head("Previous HEAD position was", old.commit);
615
782c2d65
DB
616 update_refs_for_switch(opts, &old, new);
617
291d823e
JH
618 ret = post_checkout_hook(old.commit, new->commit, 1);
619 return ret || opts->writeout_error;
782c2d65
DB
620}
621
0cf8581e
JH
622static int git_checkout_config(const char *var, const char *value, void *cb)
623{
175f6e59
JS
624 if (!strcmp(var, "diff.ignoresubmodules")) {
625 struct checkout_opts *opts = cb;
626 handle_ignore_submodules_arg(&opts->diff_options, value);
627 return 0;
628 }
23b4c7bc
JL
629
630 if (!prefixcmp(var, "submodule."))
631 return parse_submodule_config_option(var, value);
632
175f6e59 633 return git_xmerge_config(var, value, NULL);
0cf8581e
JH
634}
635
4f353658
TR
636static int interactive_checkout(const char *revision, const char **pathspec,
637 struct checkout_opts *opts)
638{
639 return run_add_interactive(revision, "--patch=checkout", pathspec);
640}
641
70c9ac2f
JH
642struct tracking_name_data {
643 const char *name;
644 char *remote;
645 int unique;
646};
647
648static int check_tracking_name(const char *refname, const unsigned char *sha1,
649 int flags, void *cb_data)
650{
651 struct tracking_name_data *cb = cb_data;
652 const char *slash;
653
654 if (prefixcmp(refname, "refs/remotes/"))
655 return 0;
656 slash = strchr(refname + 13, '/');
657 if (!slash || strcmp(slash + 1, cb->name))
658 return 0;
659 if (cb->remote) {
660 cb->unique = 0;
661 return 0;
662 }
663 cb->remote = xstrdup(refname);
664 return 0;
665}
666
667static const char *unique_tracking_name(const char *name)
668{
66dbfd55
GV
669 struct tracking_name_data cb_data = { NULL, NULL, 1 };
670 cb_data.name = name;
70c9ac2f
JH
671 for_each_ref(check_tracking_name, &cb_data);
672 if (cb_data.unique)
673 return cb_data.remote;
674 free(cb_data.remote);
675 return NULL;
676}
4f353658 677
09ebad6f
JN
678static int parse_branchname_arg(int argc, const char **argv,
679 int dwim_new_local_branch_ok,
680 struct branch_info *new,
681 struct tree **source_tree,
682 unsigned char rev[20],
683 const char **new_branch)
684{
685 int argcount = 0;
686 unsigned char branch_rev[20];
687 const char *arg;
688 int has_dash_dash;
689
690 /*
691 * case 1: git checkout <ref> -- [<paths>]
692 *
693 * <ref> must be a valid tree, everything after the '--' must be
694 * a path.
695 *
696 * case 2: git checkout -- [<paths>]
697 *
698 * everything after the '--' must be paths.
699 *
700 * case 3: git checkout <something> [<paths>]
701 *
702 * With no paths, if <something> is a commit, that is to
703 * switch to the branch or detach HEAD at it. As a special case,
704 * if <something> is A...B (missing A or B means HEAD but you can
705 * omit at most one side), and if there is a unique merge base
706 * between A and B, A...B names that merge base.
707 *
708 * With no paths, if <something> is _not_ a commit, no -t nor -b
709 * was given, and there is a tracking branch whose name is
710 * <something> in one and only one remote, then this is a short-hand
711 * to fork local <something> from that remote tracking branch.
712 *
713 * Otherwise <something> shall not be ambiguous.
714 * - If it's *only* a reference, treat it like case (1).
715 * - If it's only a path, treat it like case (2).
716 * - else: fail.
717 *
718 */
719 if (!argc)
720 return 0;
721
722 if (!strcmp(argv[0], "--")) /* case (2) */
723 return 1;
724
725 arg = argv[0];
726 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
727
728 if (!strcmp(arg, "-"))
729 arg = "@{-1}";
730
731 if (get_sha1_mb(arg, rev)) {
732 if (has_dash_dash) /* case (1) */
733 die("invalid reference: %s", arg);
734 if (dwim_new_local_branch_ok &&
735 !check_filename(NULL, arg) &&
736 argc == 1) {
737 const char *remote = unique_tracking_name(arg);
738 if (!remote || get_sha1(remote, rev))
739 return argcount;
740 *new_branch = arg;
741 arg = remote;
742 /* DWIMmed to create local branch */
743 } else {
744 return argcount;
745 }
746 }
747
748 /* we can't end up being in (2) anymore, eat the argument */
749 argcount++;
750 argv++;
751 argc--;
752
753 new->name = arg;
754 setup_branch_path(new);
755
756 if (check_ref_format(new->path) == CHECK_REF_FORMAT_OK &&
757 resolve_ref(new->path, branch_rev, 1, NULL))
758 hashcpy(rev, branch_rev);
759 else
760 new->path = NULL; /* not an existing branch */
761
762 new->commit = lookup_commit_reference_gently(rev, 1);
763 if (!new->commit) {
764 /* not a commit */
765 *source_tree = parse_tree_indirect(rev);
766 } else {
767 parse_commit(new->commit);
768 *source_tree = new->commit->tree;
769 }
770
771 if (!*source_tree) /* case (1): want a tree */
772 die("reference is not a tree: %s", arg);
773 if (!has_dash_dash) {/* case (3 -> 1) */
774 /*
775 * Do not complain the most common case
776 * git checkout branch
777 * even if there happen to be a file called 'branch';
778 * it would be extremely annoying.
779 */
780 if (argc)
781 verify_non_filename(NULL, arg);
782 } else {
783 argcount++;
784 argv++;
785 argc--;
786 }
787
788 return argcount;
789}
790
782c2d65
DB
791int cmd_checkout(int argc, const char **argv, const char *prefix)
792{
793 struct checkout_opts opts;
09ebad6f 794 unsigned char rev[20];
782c2d65
DB
795 struct branch_info new;
796 struct tree *source_tree = NULL;
eac5a401 797 char *conflict_style = NULL;
4f353658 798 int patch_mode = 0;
46148dd7 799 int dwim_new_local_branch = 1;
782c2d65
DB
800 struct option options[] = {
801 OPT__QUIET(&opts.quiet),
4c688751
TRC
802 OPT_STRING('b', NULL, &opts.new_branch, "branch",
803 "create and checkout a new branch"),
02ac9837
TRC
804 OPT_STRING('B', NULL, &opts.new_branch_force, "branch",
805 "create/reset and checkout a branch"),
3695dc0a
DKF
806 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "create reflog for new branch"),
807 OPT_SET_INT('t', "track", &opts.track, "set upstream info for new branch",
9ed36cfa 808 BRANCH_TRACK_EXPLICIT),
9db5ebf4 809 OPT_STRING(0, "orphan", &opts.new_orphan_branch, "new branch", "new unparented branch"),
3695dc0a 810 OPT_SET_INT('2', "ours", &opts.writeout_stage, "checkout our version for unmerged files",
38901a48 811 2),
3695dc0a 812 OPT_SET_INT('3', "theirs", &opts.writeout_stage, "checkout their version for unmerged files",
38901a48 813 3),
3695dc0a
DKF
814 OPT_BOOLEAN('f', "force", &opts.force, "force checkout (throw away local modifications)"),
815 OPT_BOOLEAN('m', "merge", &opts.merge, "perform a 3-way merge with the new branch"),
eac5a401
JH
816 OPT_STRING(0, "conflict", &conflict_style, "style",
817 "conflict style (merge or diff3)"),
4f353658 818 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
46148dd7
JH
819 { OPTION_BOOLEAN, 0, "guess", &dwim_new_local_branch, NULL,
820 "second guess 'git checkout no-such-branch'",
821 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
b249b552 822 OPT_END(),
782c2d65
DB
823 };
824
825 memset(&opts, 0, sizeof(opts));
826 memset(&new, 0, sizeof(new));
827
23b4c7bc 828 gitmodules_config();
175f6e59 829 git_config(git_checkout_config, &opts);
782c2d65 830
9188ed89 831 opts.track = BRANCH_TRACK_UNSPECIFIED;
782c2d65 832
37782920 833 argc = parse_options(argc, argv, prefix, options, checkout_usage,
f5242ebf 834 PARSE_OPT_KEEP_DASHDASH);
859fdaba 835
02ac9837
TRC
836 /* we can assume from now on new_branch = !new_branch_force */
837 if (opts.new_branch && opts.new_branch_force)
838 die("-B cannot be used with -b");
839
840 /* copy -B over to -b, so that we can just check the latter */
841 if (opts.new_branch_force)
842 opts.new_branch = opts.new_branch_force;
843
4f353658
TR
844 if (patch_mode && (opts.track > 0 || opts.new_branch
845 || opts.new_branch_log || opts.merge || opts.force))
846 die ("--patch is incompatible with all other options");
847
bb0ceb62 848 /* --track without -b should DWIM */
9188ed89
AR
849 if (0 < opts.track && !opts.new_branch) {
850 const char *argv0 = argv[0];
851 if (!argc || !strcmp(argv0, "--"))
bb0ceb62 852 die ("--track needs a branch name");
9188ed89
AR
853 if (!prefixcmp(argv0, "refs/"))
854 argv0 += 5;
855 if (!prefixcmp(argv0, "remotes/"))
856 argv0 += 8;
857 argv0 = strchr(argv0, '/');
858 if (!argv0 || !argv0[1])
bb0ceb62 859 die ("Missing branch name; try -b");
9188ed89 860 opts.new_branch = argv0 + 1;
bb0ceb62
JS
861 }
862
9db5ebf4
EM
863 if (opts.new_orphan_branch) {
864 if (opts.new_branch)
02ac9837 865 die("--orphan and -b|-B are mutually exclusive");
3631bf77
EM
866 if (opts.track > 0)
867 die("--orphan cannot be used with -t");
9db5ebf4
EM
868 opts.new_branch = opts.new_orphan_branch;
869 }
870
eac5a401
JH
871 if (conflict_style) {
872 opts.merge = 1; /* implied */
873 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
874 }
875
859fdaba
PH
876 if (opts.force && opts.merge)
877 die("git checkout: -f and -m are incompatible");
878
879 /*
09ebad6f
JN
880 * Extract branch name from command line arguments, so
881 * all that is left is pathspecs.
859fdaba 882 *
09ebad6f 883 * Handle
70c9ac2f 884 *
09ebad6f
JN
885 * 1) git checkout <tree> -- [<paths>]
886 * 2) git checkout -- [<paths>]
887 * 3) git checkout <something> [<paths>]
859fdaba 888 *
09ebad6f
JN
889 * including "last branch" syntax and DWIM-ery for names of
890 * remote branches, erroring out for invalid or ambiguous cases.
859fdaba 891 */
782c2d65 892 if (argc) {
09ebad6f
JN
893 int dwim_ok =
894 !patch_mode &&
895 dwim_new_local_branch &&
896 opts.track == BRANCH_TRACK_UNSPECIFIED &&
897 !opts.new_branch;
898 int n = parse_branchname_arg(argc, argv, dwim_ok,
899 &new, &source_tree, rev, &opts.new_branch);
900 argv += n;
901 argc -= n;
782c2d65
DB
902 }
903
70c9ac2f
JH
904 if (opts.track == BRANCH_TRACK_UNSPECIFIED)
905 opts.track = git_branch_track;
906
782c2d65
DB
907 if (argc) {
908 const char **pathspec = get_pathspec(prefix, argv);
301e42ed
AR
909
910 if (!pathspec)
911 die("invalid path specification");
912
4f353658
TR
913 if (patch_mode)
914 return interactive_checkout(new.name, pathspec, &opts);
915
782c2d65 916 /* Checkout paths */
0cf8581e 917 if (opts.new_branch) {
782c2d65 918 if (argc == 1) {
db941099 919 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]);
782c2d65 920 } else {
db941099 921 die("git checkout: updating paths is incompatible with switching branches.");
782c2d65
DB
922 }
923 }
924
0cf8581e
JH
925 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
926 die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");
927
db941099 928 return checkout_paths(source_tree, pathspec, &opts);
782c2d65
DB
929 }
930
4f353658
TR
931 if (patch_mode)
932 return interactive_checkout(new.name, NULL, &opts);
933
352eadc4 934 if (opts.new_branch) {
f285a2d7 935 struct strbuf buf = STRBUF_INIT;
a2fab531
JH
936 if (strbuf_check_branch_ref(&buf, opts.new_branch))
937 die("git checkout: we do not like '%s' as a branch name.",
938 opts.new_branch);
02ac9837
TRC
939 if (!get_sha1(buf.buf, rev)) {
940 opts.branch_exists = 1;
941 if (!opts.new_branch_force)
942 die("git checkout: branch %s already exists",
943 opts.new_branch);
944 }
352eadc4
DB
945 strbuf_release(&buf);
946 }
947
782c2d65
DB
948 if (new.name && !new.commit) {
949 die("Cannot switch branch to a non-commit.");
950 }
38901a48
JH
951 if (opts.writeout_stage)
952 die("--ours/--theirs is incompatible with switching branches.");
782c2d65 953
75ea38df 954 return switch_branches(&opts, &new);
782c2d65 955}