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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"
782c2d65
DB
21
22static const char * const checkout_usage[] = {
23 "git checkout [options] <branch>",
24 "git checkout [options] [<branch>] -- <file>...",
25 NULL,
26};
27
db941099
JH
28struct checkout_opts {
29 int quiet;
30 int merge;
31 int force;
38901a48 32 int writeout_stage;
db941099
JH
33 int writeout_error;
34
35 const char *new_branch;
36 int new_branch_log;
37 enum branch_track track;
38};
39
782c2d65
DB
40static int post_checkout_hook(struct commit *old, struct commit *new,
41 int changed)
42{
ae98a008
SB
43 return run_hook(NULL, "post-checkout",
44 sha1_to_hex(old ? old->object.sha1 : null_sha1),
45 sha1_to_hex(new ? new->object.sha1 : null_sha1),
46 changed ? "1" : "0", NULL);
2292ce47
SB
47 /* "new" can be NULL when checking out from the index before
48 a commit exists. */
ae98a008 49
782c2d65
DB
50}
51
52static int update_some(const unsigned char *sha1, const char *base, int baselen,
671f0707 53 const char *pathname, unsigned mode, int stage, void *context)
782c2d65
DB
54{
55 int len;
56 struct cache_entry *ce;
57
782c2d65
DB
58 if (S_ISDIR(mode))
59 return READ_TREE_RECURSIVE;
60
61 len = baselen + strlen(pathname);
62 ce = xcalloc(1, cache_entry_size(len));
63 hashcpy(ce->sha1, sha1);
64 memcpy(ce->name, base, baselen);
65 memcpy(ce->name + baselen, pathname, len - baselen);
66 ce->ce_flags = create_ce_flags(len, 0);
67 ce->ce_mode = create_ce_mode(mode);
68 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
69 return 0;
70}
71
72static int read_tree_some(struct tree *tree, const char **pathspec)
73{
671f0707 74 read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
782c2d65 75
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DB
76 /* update the index with the given tree's info
77 * for all args, expanding wildcards, and exit
78 * with any non-zero return code.
79 */
80 return 0;
81}
82
8fdcf312
JH
83static int skip_same_name(struct cache_entry *ce, int pos)
84{
85 while (++pos < active_nr &&
86 !strcmp(active_cache[pos]->name, ce->name))
87 ; /* skip */
88 return pos;
89}
90
38901a48
JH
91static int check_stage(int stage, struct cache_entry *ce, int pos)
92{
93 while (pos < active_nr &&
94 !strcmp(active_cache[pos]->name, ce->name)) {
95 if (ce_stage(active_cache[pos]) == stage)
96 return 0;
97 pos++;
98 }
99 return error("path '%s' does not have %s version",
100 ce->name,
101 (stage == 2) ? "our" : "their");
102}
103
0cf8581e
JH
104static int check_all_stages(struct cache_entry *ce, int pos)
105{
106 if (ce_stage(ce) != 1 ||
107 active_nr <= pos + 2 ||
108 strcmp(active_cache[pos+1]->name, ce->name) ||
109 ce_stage(active_cache[pos+1]) != 2 ||
110 strcmp(active_cache[pos+2]->name, ce->name) ||
111 ce_stage(active_cache[pos+2]) != 3)
112 return error("path '%s' does not have all three versions",
113 ce->name);
114 return 0;
115}
116
38901a48
JH
117static int checkout_stage(int stage, struct cache_entry *ce, int pos,
118 struct checkout *state)
119{
120 while (pos < active_nr &&
121 !strcmp(active_cache[pos]->name, ce->name)) {
122 if (ce_stage(active_cache[pos]) == stage)
123 return checkout_entry(active_cache[pos], state, NULL);
124 pos++;
125 }
126 return error("path '%s' does not have %s version",
127 ce->name,
128 (stage == 2) ? "our" : "their");
129}
8fdcf312 130
0cf8581e
JH
131/* NEEDSWORK: share with merge-recursive */
132static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
133{
134 unsigned long size;
135 enum object_type type;
136
137 if (!hashcmp(sha1, null_sha1)) {
138 mm->ptr = xstrdup("");
139 mm->size = 0;
140 return;
141 }
142
143 mm->ptr = read_sha1_file(sha1, &type, &size);
144 if (!mm->ptr || type != OBJ_BLOB)
145 die("unable to read blob object %s", sha1_to_hex(sha1));
146 mm->size = size;
147}
148
149static int checkout_merged(int pos, struct checkout *state)
150{
151 struct cache_entry *ce = active_cache[pos];
152 const char *path = ce->name;
153 mmfile_t ancestor, ours, theirs;
154 int status;
155 unsigned char sha1[20];
156 mmbuffer_t result_buf;
157
158 if (ce_stage(ce) != 1 ||
159 active_nr <= pos + 2 ||
160 strcmp(active_cache[pos+1]->name, path) ||
161 ce_stage(active_cache[pos+1]) != 2 ||
162 strcmp(active_cache[pos+2]->name, path) ||
163 ce_stage(active_cache[pos+2]) != 3)
164 return error("path '%s' does not have all 3 versions", path);
165
166 fill_mm(active_cache[pos]->sha1, &ancestor);
167 fill_mm(active_cache[pos+1]->sha1, &ours);
168 fill_mm(active_cache[pos+2]->sha1, &theirs);
169
170 status = ll_merge(&result_buf, path, &ancestor,
6d6f9acc 171 &ours, "ours", &theirs, "theirs", 0);
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JH
172 free(ancestor.ptr);
173 free(ours.ptr);
174 free(theirs.ptr);
175 if (status < 0 || !result_buf.ptr) {
176 free(result_buf.ptr);
177 return error("path '%s': cannot merge", path);
178 }
179
180 /*
181 * NEEDSWORK:
182 * There is absolutely no reason to write this as a blob object
3ea3c215 183 * and create a phony cache entry just to leak. This hack is
0cf8581e
JH
184 * primarily to get to the write_entry() machinery that massages
185 * the contents to work-tree format and writes out which only
186 * allows it for a cache entry. The code in write_entry() needs
187 * to be refactored to allow us to feed a <buffer, size, mode>
188 * instead of a cache entry. Such a refactoring would help
189 * merge_recursive as well (it also writes the merge result to the
190 * object database even when it may contain conflicts).
191 */
192 if (write_sha1_file(result_buf.ptr, result_buf.size,
193 blob_type, sha1))
194 die("Unable to add merge result for '%s'", path);
195 ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
196 sha1,
197 path, 2, 0);
048f2762
DP
198 if (!ce)
199 die("make_cache_entry failed for path '%s'", path);
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JH
200 status = checkout_entry(ce, state, NULL);
201 return status;
202}
8fdcf312 203
db941099
JH
204static int checkout_paths(struct tree *source_tree, const char **pathspec,
205 struct checkout_opts *opts)
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DB
206{
207 int pos;
208 struct checkout state;
209 static char *ps_matched;
210 unsigned char rev[20];
211 int flag;
212 struct commit *head;
d2b3691b 213 int errs = 0;
38901a48 214 int stage = opts->writeout_stage;
0cf8581e 215 int merge = opts->merge;
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DB
216 int newfd;
217 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
218
219 newfd = hold_locked_index(lock_file, 1);
53996fe5 220 if (read_cache_preload(pathspec) < 0)
b96524f8 221 return error("corrupt index file");
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DB
222
223 if (source_tree)
224 read_tree_some(source_tree, pathspec);
225
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DB
226 for (pos = 0; pathspec[pos]; pos++)
227 ;
228 ps_matched = xcalloc(1, pos);
229
230 for (pos = 0; pos < active_nr; pos++) {
231 struct cache_entry *ce = active_cache[pos];
0b50922a 232 match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, ps_matched);
782c2d65
DB
233 }
234
235 if (report_path_error(ps_matched, pathspec, 0))
236 return 1;
237
4421a823
JH
238 /* "checkout -m path" to recreate conflicted state */
239 if (opts->merge)
240 unmerge_cache(pathspec);
241
8fdcf312
JH
242 /* Any unmerged paths? */
243 for (pos = 0; pos < active_nr; pos++) {
244 struct cache_entry *ce = active_cache[pos];
0b50922a 245 if (match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, NULL)) {
8fdcf312
JH
246 if (!ce_stage(ce))
247 continue;
db941099
JH
248 if (opts->force) {
249 warning("path '%s' is unmerged", ce->name);
38901a48
JH
250 } else if (stage) {
251 errs |= check_stage(stage, ce, pos);
0cf8581e
JH
252 } else if (opts->merge) {
253 errs |= check_all_stages(ce, pos);
db941099
JH
254 } else {
255 errs = 1;
256 error("path '%s' is unmerged", ce->name);
257 }
8fdcf312
JH
258 pos = skip_same_name(ce, pos) - 1;
259 }
260 }
261 if (errs)
262 return 1;
263
d2b3691b 264 /* Now we are committed to check them out */
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DB
265 memset(&state, 0, sizeof(state));
266 state.force = 1;
267 state.refresh_cache = 1;
268 for (pos = 0; pos < active_nr; pos++) {
269 struct cache_entry *ce = active_cache[pos];
0b50922a 270 if (match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, NULL)) {
8fdcf312
JH
271 if (!ce_stage(ce)) {
272 errs |= checkout_entry(ce, &state, NULL);
273 continue;
274 }
38901a48
JH
275 if (stage)
276 errs |= checkout_stage(stage, ce, pos, &state);
0cf8581e
JH
277 else if (merge)
278 errs |= checkout_merged(pos, &state);
8fdcf312 279 pos = skip_same_name(ce, pos) - 1;
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DB
280 }
281 }
282
75336878
DB
283 if (write_cache(newfd, active_cache, active_nr) ||
284 commit_locked_index(lock_file))
285 die("unable to write new index file");
286
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DB
287 resolve_ref("HEAD", rev, 0, &flag);
288 head = lookup_commit_reference_gently(rev, 1);
289
d2b3691b
JH
290 errs |= post_checkout_hook(head, head, 0);
291 return errs;
782c2d65
DB
292}
293
294static void show_local_changes(struct object *head)
295{
296 struct rev_info rev;
297 /* I think we want full paths, even if we're in a subdirectory. */
298 init_revisions(&rev, NULL);
299 rev.abbrev = 0;
300 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
e752f4bb
KC
301 if (diff_setup_done(&rev.diffopt) < 0)
302 die("diff_setup_done failed");
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DB
303 add_pending_object(&rev, head, NULL);
304 run_diff_index(&rev, 0);
305}
306
307static void describe_detached_head(char *msg, struct commit *commit)
308{
f285a2d7 309 struct strbuf sb = STRBUF_INIT;
dd2e794a 310 struct pretty_print_context ctx = {0};
782c2d65 311 parse_commit(commit);
dd2e794a 312 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, &ctx);
782c2d65
DB
313 fprintf(stderr, "%s %s... %s\n", msg,
314 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
315 strbuf_release(&sb);
316}
317
6286a08d 318static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
782c2d65
DB
319{
320 struct unpack_trees_options opts;
321 struct tree_desc tree_desc;
bc052d7f 322
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DB
323 memset(&opts, 0, sizeof(opts));
324 opts.head_idx = -1;
6286a08d
JH
325 opts.update = worktree;
326 opts.skip_unmerged = !worktree;
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DB
327 opts.reset = 1;
328 opts.merge = 1;
329 opts.fn = oneway_merge;
6286a08d 330 opts.verbose_update = !o->quiet;
34110cd4
LT
331 opts.src_index = &the_index;
332 opts.dst_index = &the_index;
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DB
333 parse_tree(tree);
334 init_tree_desc(&tree_desc, tree->buffer, tree->size);
291d823e
JH
335 switch (unpack_trees(1, &tree_desc, &opts)) {
336 case -2:
337 o->writeout_error = 1;
338 /*
339 * We return 0 nevertheless, as the index is all right
340 * and more importantly we have made best efforts to
341 * update paths in the work tree, and we cannot revert
342 * them.
343 */
344 case 0:
345 return 0;
346 default:
84a5750b 347 return 128;
291d823e 348 }
782c2d65
DB
349}
350
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DB
351struct branch_info {
352 const char *name; /* The short name used */
353 const char *path; /* The full name of a real branch */
354 struct commit *commit; /* The named commit */
355};
356
357static void setup_branch_path(struct branch_info *branch)
358{
f285a2d7 359 struct strbuf buf = STRBUF_INIT;
ae5a6c36 360
a552de75
JH
361 strbuf_branchname(&buf, branch->name);
362 if (strcmp(buf.buf, branch->name))
ae5a6c36 363 branch->name = xstrdup(buf.buf);
a552de75 364 strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
782c2d65
DB
365 branch->path = strbuf_detach(&buf, NULL);
366}
367
368static int merge_working_tree(struct checkout_opts *opts,
75ea38df 369 struct branch_info *old, struct branch_info *new)
782c2d65
DB
370{
371 int ret;
372 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
373 int newfd = hold_locked_index(lock_file, 1);
b96524f8 374
53996fe5 375 if (read_cache_preload(NULL) < 0)
b96524f8 376 return error("corrupt index file");
782c2d65 377
cfc5789a 378 resolve_undo_clear();
782c2d65 379 if (opts->force) {
6286a08d 380 ret = reset_tree(new->commit->tree, opts, 1);
782c2d65
DB
381 if (ret)
382 return ret;
383 } else {
384 struct tree_desc trees[2];
385 struct tree *tree;
386 struct unpack_trees_options topts;
bc052d7f 387
782c2d65
DB
388 memset(&topts, 0, sizeof(topts));
389 topts.head_idx = -1;
34110cd4
LT
390 topts.src_index = &the_index;
391 topts.dst_index = &the_index;
782c2d65 392
8ccba008
JH
393 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
394
782c2d65
DB
395 refresh_cache(REFRESH_QUIET);
396
397 if (unmerged_cache()) {
04c9e11f
JH
398 error("you need to resolve your current index first");
399 return 1;
782c2d65 400 }
04c9e11f
JH
401
402 /* 2-way merge to the new branch */
fa7b3c2f 403 topts.initial_checkout = is_cache_unborn();
04c9e11f
JH
404 topts.update = 1;
405 topts.merge = 1;
64da3ae5 406 topts.gently = opts->merge && old->commit;
04c9e11f
JH
407 topts.verbose_update = !opts->quiet;
408 topts.fn = twoway_merge;
409 topts.dir = xcalloc(1, sizeof(*topts.dir));
7c4c97c0 410 topts.dir->flags |= DIR_SHOW_IGNORED;
04c9e11f 411 topts.dir->exclude_per_dir = ".gitignore";
cc580af8
JK
412 tree = parse_tree_indirect(old->commit ?
413 old->commit->object.sha1 :
414 (unsigned char *)EMPTY_TREE_SHA1_BIN);
04c9e11f
JH
415 init_tree_desc(&trees[0], tree->buffer, tree->size);
416 tree = parse_tree_indirect(new->commit->object.sha1);
417 init_tree_desc(&trees[1], tree->buffer, tree->size);
418
291d823e 419 ret = unpack_trees(2, trees, &topts);
49d833dc 420 if (ret == -1) {
782c2d65
DB
421 /*
422 * Unpack couldn't do a trivial merge; either
423 * give up or do a real merge, depending on
424 * whether the merge flag was used.
425 */
426 struct tree *result;
427 struct tree *work;
8a2fce18 428 struct merge_options o;
782c2d65
DB
429 if (!opts->merge)
430 return 1;
64da3ae5
JH
431
432 /*
433 * Without old->commit, the below is the same as
434 * the two-tree unpack we already tried and failed.
435 */
436 if (!old->commit)
437 return 1;
782c2d65
DB
438
439 /* Do more real merge */
440
441 /*
442 * We update the index fully, then write the
443 * tree from the index, then merge the new
444 * branch with the current tree, with the old
445 * branch as the base. Then we reset the index
446 * (but not the working tree) to the new
447 * branch, leaving the working tree as the
448 * merged version, but skipping unmerged
449 * entries in the index.
450 */
451
7ae02a30 452 add_files_to_cache(NULL, NULL, 0);
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;
8a2fce18
MV
460 o.branch1 = new->name;
461 o.branch2 = "local";
462 merge_trees(&o, new->commit->tree, work,
463 old->commit->tree, &result);
6286a08d 464 ret = reset_tree(new->commit->tree, opts, 0);
84a5750b
JH
465 if (ret)
466 return ret;
782c2d65
DB
467 }
468 }
469
470 if (write_cache(newfd, active_cache, active_nr) ||
471 commit_locked_index(lock_file))
472 die("unable to write new index file");
473
7fe4a728 474 if (!opts->force && !opts->quiet)
782c2d65
DB
475 show_local_changes(&new->commit->object);
476
477 return 0;
478}
479
6d21bf96 480static void report_tracking(struct branch_info *new)
79a1e6b4 481{
6d21bf96 482 struct strbuf sb = STRBUF_INIT;
b56fca07 483 struct branch *branch = branch_get(new->name);
79a1e6b4 484
6d21bf96 485 if (!format_tracking_info(branch, &sb))
79a1e6b4 486 return;
6d21bf96
JH
487 fputs(sb.buf, stdout);
488 strbuf_release(&sb);
b0030db3 489}
79a1e6b4 490
782c2d65
DB
491static void update_refs_for_switch(struct checkout_opts *opts,
492 struct branch_info *old,
493 struct branch_info *new)
494{
f285a2d7 495 struct strbuf msg = STRBUF_INIT;
782c2d65
DB
496 const char *old_desc;
497 if (opts->new_branch) {
498 create_branch(old->name, opts->new_branch, new->name, 0,
499 opts->new_branch_log, opts->track);
500 new->name = opts->new_branch;
501 setup_branch_path(new);
502 }
503
782c2d65 504 old_desc = old->name;
323e00fd 505 if (!old_desc && old->commit)
782c2d65
DB
506 old_desc = sha1_to_hex(old->commit->object.sha1);
507 strbuf_addf(&msg, "checkout: moving from %s to %s",
323e00fd 508 old_desc ? old_desc : "(invalid)", new->name);
782c2d65
DB
509
510 if (new->path) {
511 create_symref("HEAD", new->path, msg.buf);
512 if (!opts->quiet) {
513 if (old->path && !strcmp(new->path, old->path))
714fddf2 514 fprintf(stderr, "Already on '%s'\n",
782c2d65
DB
515 new->name);
516 else
714fddf2 517 fprintf(stderr, "Switched to%s branch '%s'\n",
782c2d65
DB
518 opts->new_branch ? " a new" : "",
519 new->name);
520 }
521 } else if (strcmp(new->name, "HEAD")) {
522 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
523 REF_NODEREF, DIE_ON_ERR);
524 if (!opts->quiet) {
525 if (old->path)
714fddf2 526 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);
782c2d65
DB
527 describe_detached_head("HEAD is now at", new->commit);
528 }
529 }
530 remove_branch_state();
531 strbuf_release(&msg);
b0030db3 532 if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
6d21bf96 533 report_tracking(new);
782c2d65
DB
534}
535
75ea38df 536static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
782c2d65
DB
537{
538 int ret = 0;
539 struct branch_info old;
540 unsigned char rev[20];
541 int flag;
542 memset(&old, 0, sizeof(old));
543 old.path = resolve_ref("HEAD", rev, 0, &flag);
544 old.commit = lookup_commit_reference_gently(rev, 1);
545 if (!(flag & REF_ISSYMREF))
546 old.path = NULL;
547
548 if (old.path && !prefixcmp(old.path, "refs/heads/"))
549 old.name = old.path + strlen("refs/heads/");
550
551 if (!new->name) {
552 new->name = "HEAD";
553 new->commit = old.commit;
554 if (!new->commit)
555 die("You are on a branch yet to be born");
556 parse_commit(new->commit);
557 }
558
75ea38df 559 ret = merge_working_tree(opts, &old, new);
782c2d65
DB
560 if (ret)
561 return ret;
562
77ebd56d
DC
563 /*
564 * If we were on a detached HEAD, but have now moved to
565 * a new commit, we want to mention the old commit once more
566 * to remind the user that it might be lost.
567 */
568 if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
569 describe_detached_head("Previous HEAD position was", old.commit);
570
782c2d65
DB
571 update_refs_for_switch(opts, &old, new);
572
291d823e
JH
573 ret = post_checkout_hook(old.commit, new->commit, 1);
574 return ret || opts->writeout_error;
782c2d65
DB
575}
576
0cf8581e
JH
577static int git_checkout_config(const char *var, const char *value, void *cb)
578{
579 return git_xmerge_config(var, value, cb);
580}
581
4f353658
TR
582static int interactive_checkout(const char *revision, const char **pathspec,
583 struct checkout_opts *opts)
584{
585 return run_add_interactive(revision, "--patch=checkout", pathspec);
586}
587
70c9ac2f
JH
588struct tracking_name_data {
589 const char *name;
590 char *remote;
591 int unique;
592};
593
594static int check_tracking_name(const char *refname, const unsigned char *sha1,
595 int flags, void *cb_data)
596{
597 struct tracking_name_data *cb = cb_data;
598 const char *slash;
599
600 if (prefixcmp(refname, "refs/remotes/"))
601 return 0;
602 slash = strchr(refname + 13, '/');
603 if (!slash || strcmp(slash + 1, cb->name))
604 return 0;
605 if (cb->remote) {
606 cb->unique = 0;
607 return 0;
608 }
609 cb->remote = xstrdup(refname);
610 return 0;
611}
612
613static const char *unique_tracking_name(const char *name)
614{
615 struct tracking_name_data cb_data = { name, NULL, 1 };
616 for_each_ref(check_tracking_name, &cb_data);
617 if (cb_data.unique)
618 return cb_data.remote;
619 free(cb_data.remote);
620 return NULL;
621}
4f353658 622
782c2d65
DB
623int cmd_checkout(int argc, const char **argv, const char *prefix)
624{
625 struct checkout_opts opts;
626 unsigned char rev[20];
627 const char *arg;
628 struct branch_info new;
629 struct tree *source_tree = NULL;
eac5a401 630 char *conflict_style = NULL;
4f353658 631 int patch_mode = 0;
46148dd7 632 int dwim_new_local_branch = 1;
782c2d65
DB
633 struct option options[] = {
634 OPT__QUIET(&opts.quiet),
635 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
636 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
498a6e7e 637 OPT_SET_INT('t', "track", &opts.track, "track",
9ed36cfa 638 BRANCH_TRACK_EXPLICIT),
38901a48
JH
639 OPT_SET_INT('2', "ours", &opts.writeout_stage, "stage",
640 2),
641 OPT_SET_INT('3', "theirs", &opts.writeout_stage, "stage",
642 3),
f7aec129 643 OPT_BOOLEAN('f', "force", &opts.force, "force"),
eac5a401
JH
644 OPT_BOOLEAN('m', "merge", &opts.merge, "merge"),
645 OPT_STRING(0, "conflict", &conflict_style, "style",
646 "conflict style (merge or diff3)"),
4f353658 647 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
46148dd7
JH
648 { OPTION_BOOLEAN, 0, "guess", &dwim_new_local_branch, NULL,
649 "second guess 'git checkout no-such-branch'",
650 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
b249b552 651 OPT_END(),
782c2d65 652 };
859fdaba 653 int has_dash_dash;
782c2d65
DB
654
655 memset(&opts, 0, sizeof(opts));
656 memset(&new, 0, sizeof(new));
657
0cf8581e 658 git_config(git_checkout_config, NULL);
782c2d65 659
9188ed89 660 opts.track = BRANCH_TRACK_UNSPECIFIED;
782c2d65 661
37782920 662 argc = parse_options(argc, argv, prefix, options, checkout_usage,
f5242ebf 663 PARSE_OPT_KEEP_DASHDASH);
859fdaba 664
4f353658
TR
665 if (patch_mode && (opts.track > 0 || opts.new_branch
666 || opts.new_branch_log || opts.merge || opts.force))
667 die ("--patch is incompatible with all other options");
668
bb0ceb62 669 /* --track without -b should DWIM */
9188ed89
AR
670 if (0 < opts.track && !opts.new_branch) {
671 const char *argv0 = argv[0];
672 if (!argc || !strcmp(argv0, "--"))
bb0ceb62 673 die ("--track needs a branch name");
9188ed89
AR
674 if (!prefixcmp(argv0, "refs/"))
675 argv0 += 5;
676 if (!prefixcmp(argv0, "remotes/"))
677 argv0 += 8;
678 argv0 = strchr(argv0, '/');
679 if (!argv0 || !argv0[1])
bb0ceb62 680 die ("Missing branch name; try -b");
9188ed89 681 opts.new_branch = argv0 + 1;
bb0ceb62
JS
682 }
683
eac5a401
JH
684 if (conflict_style) {
685 opts.merge = 1; /* implied */
686 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
687 }
688
859fdaba
PH
689 if (opts.force && opts.merge)
690 die("git checkout: -f and -m are incompatible");
691
692 /*
693 * case 1: git checkout <ref> -- [<paths>]
694 *
695 * <ref> must be a valid tree, everything after the '--' must be
696 * a path.
697 *
698 * case 2: git checkout -- [<paths>]
699 *
700 * everything after the '--' must be paths.
701 *
702 * case 3: git checkout <something> [<paths>]
703 *
704 * With no paths, if <something> is a commit, that is to
619a644d
JH
705 * switch to the branch or detach HEAD at it. As a special case,
706 * if <something> is A...B (missing A or B means HEAD but you can
707 * omit at most one side), and if there is a unique merge base
708 * between A and B, A...B names that merge base.
859fdaba 709 *
70c9ac2f
JH
710 * With no paths, if <something> is _not_ a commit, no -t nor -b
711 * was given, and there is a tracking branch whose name is
712 * <something> in one and only one remote, then this is a short-hand
713 * to fork local <something> from that remote tracking branch.
714 *
859fdaba
PH
715 * Otherwise <something> shall not be ambiguous.
716 * - If it's *only* a reference, treat it like case (1).
717 * - If it's only a path, treat it like case (2).
718 * - else: fail.
719 *
720 */
782c2d65 721 if (argc) {
859fdaba
PH
722 if (!strcmp(argv[0], "--")) { /* case (2) */
723 argv++;
724 argc--;
725 goto no_reference;
726 }
727
782c2d65 728 arg = argv[0];
859fdaba
PH
729 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
730
696acf45
TR
731 if (!strcmp(arg, "-"))
732 arg = "@{-1}";
733
619a644d 734 if (get_sha1_mb(arg, rev)) {
859fdaba
PH
735 if (has_dash_dash) /* case (1) */
736 die("invalid reference: %s", arg);
70c9ac2f 737 if (!patch_mode &&
46148dd7 738 dwim_new_local_branch &&
70c9ac2f
JH
739 opts.track == BRANCH_TRACK_UNSPECIFIED &&
740 !opts.new_branch &&
741 !check_filename(NULL, arg) &&
742 argc == 1) {
743 const char *remote = unique_tracking_name(arg);
744 if (!remote || get_sha1(remote, rev))
745 goto no_reference;
746 opts.new_branch = arg;
747 arg = remote;
748 /* DWIMmed to create local branch */
749 }
750 else
751 goto no_reference;
859fdaba
PH
752 }
753
754 /* we can't end up being in (2) anymore, eat the argument */
755 argv++;
756 argc--;
757
3442ea4a 758 new.name = arg;
859fdaba 759 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
782c2d65 760 setup_branch_path(&new);
72a144e2
JH
761
762 if ((check_ref_format(new.path) == CHECK_REF_FORMAT_OK) &&
763 resolve_ref(new.path, rev, 1, NULL))
764 ;
782c2d65
DB
765 else
766 new.path = NULL;
767 parse_commit(new.commit);
768 source_tree = new.commit->tree;
859fdaba
PH
769 } else
770 source_tree = parse_tree_indirect(rev);
771
772 if (!source_tree) /* case (1): want a tree */
773 die("reference is not a tree: %s", arg);
774 if (!has_dash_dash) {/* case (3 -> 1) */
775 /*
776 * Do not complain the most common case
777 * git checkout branch
778 * even if there happen to be a file called 'branch';
779 * it would be extremely annoying.
780 */
781 if (argc)
782 verify_non_filename(NULL, arg);
783 }
784 else {
782c2d65
DB
785 argv++;
786 argc--;
787 }
788 }
789
859fdaba 790no_reference:
70c9ac2f
JH
791
792 if (opts.track == BRANCH_TRACK_UNSPECIFIED)
793 opts.track = git_branch_track;
794
782c2d65
DB
795 if (argc) {
796 const char **pathspec = get_pathspec(prefix, argv);
301e42ed
AR
797
798 if (!pathspec)
799 die("invalid path specification");
800
4f353658
TR
801 if (patch_mode)
802 return interactive_checkout(new.name, pathspec, &opts);
803
782c2d65 804 /* Checkout paths */
0cf8581e 805 if (opts.new_branch) {
782c2d65 806 if (argc == 1) {
db941099 807 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 808 } else {
db941099 809 die("git checkout: updating paths is incompatible with switching branches.");
782c2d65
DB
810 }
811 }
812
0cf8581e
JH
813 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
814 die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");
815
db941099 816 return checkout_paths(source_tree, pathspec, &opts);
782c2d65
DB
817 }
818
4f353658
TR
819 if (patch_mode)
820 return interactive_checkout(new.name, NULL, &opts);
821
352eadc4 822 if (opts.new_branch) {
f285a2d7 823 struct strbuf buf = STRBUF_INIT;
a2fab531
JH
824 if (strbuf_check_branch_ref(&buf, opts.new_branch))
825 die("git checkout: we do not like '%s' as a branch name.",
826 opts.new_branch);
352eadc4
DB
827 if (!get_sha1(buf.buf, rev))
828 die("git checkout: branch %s already exists", opts.new_branch);
352eadc4
DB
829 strbuf_release(&buf);
830 }
831
782c2d65
DB
832 if (new.name && !new.commit) {
833 die("Cannot switch branch to a non-commit.");
834 }
38901a48
JH
835 if (opts.writeout_stage)
836 die("--ours/--theirs is incompatible with switching branches.");
782c2d65 837
75ea38df 838 return switch_branches(&opts, &new);
782c2d65 839}