print an error message for invalid path
[git/git.git] / builtin-checkout.c
CommitLineData
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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"
8#include "unpack-trees.h"
9#include "dir.h"
10#include "run-command.h"
11#include "merge-recursive.h"
12#include "branch.h"
13#include "diff.h"
14#include "revision.h"
79a1e6b4 15#include "remote.h"
0cf8581e
JH
16#include "blob.h"
17#include "xdiff-interface.h"
18#include "ll-merge.h"
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DB
19
20static const char * const checkout_usage[] = {
21 "git checkout [options] <branch>",
22 "git checkout [options] [<branch>] -- <file>...",
23 NULL,
24};
25
db941099
JH
26struct checkout_opts {
27 int quiet;
28 int merge;
29 int force;
38901a48 30 int writeout_stage;
db941099
JH
31 int writeout_error;
32
33 const char *new_branch;
34 int new_branch_log;
35 enum branch_track track;
36};
37
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38static int post_checkout_hook(struct commit *old, struct commit *new,
39 int changed)
40{
41 struct child_process proc;
42 const char *name = git_path("hooks/post-checkout");
43 const char *argv[5];
44
45 if (access(name, X_OK) < 0)
46 return 0;
47
48 memset(&proc, 0, sizeof(proc));
49 argv[0] = name;
50 argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
51 argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
52 argv[3] = changed ? "1" : "0";
53 argv[4] = NULL;
54 proc.argv = argv;
55 proc.no_stdin = 1;
56 proc.stdout_to_stderr = 1;
57 return run_command(&proc);
58}
59
60static int update_some(const unsigned char *sha1, const char *base, int baselen,
671f0707 61 const char *pathname, unsigned mode, int stage, void *context)
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DB
62{
63 int len;
64 struct cache_entry *ce;
65
66 if (S_ISGITLINK(mode))
67 return 0;
68
69 if (S_ISDIR(mode))
70 return READ_TREE_RECURSIVE;
71
72 len = baselen + strlen(pathname);
73 ce = xcalloc(1, cache_entry_size(len));
74 hashcpy(ce->sha1, sha1);
75 memcpy(ce->name, base, baselen);
76 memcpy(ce->name + baselen, pathname, len - baselen);
77 ce->ce_flags = create_ce_flags(len, 0);
78 ce->ce_mode = create_ce_mode(mode);
79 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
80 return 0;
81}
82
83static int read_tree_some(struct tree *tree, const char **pathspec)
84{
671f0707 85 read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
782c2d65 86
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DB
87 /* update the index with the given tree's info
88 * for all args, expanding wildcards, and exit
89 * with any non-zero return code.
90 */
91 return 0;
92}
93
8fdcf312
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94static int skip_same_name(struct cache_entry *ce, int pos)
95{
96 while (++pos < active_nr &&
97 !strcmp(active_cache[pos]->name, ce->name))
98 ; /* skip */
99 return pos;
100}
101
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JH
102static int check_stage(int stage, struct cache_entry *ce, int pos)
103{
104 while (pos < active_nr &&
105 !strcmp(active_cache[pos]->name, ce->name)) {
106 if (ce_stage(active_cache[pos]) == stage)
107 return 0;
108 pos++;
109 }
110 return error("path '%s' does not have %s version",
111 ce->name,
112 (stage == 2) ? "our" : "their");
113}
114
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115static int check_all_stages(struct cache_entry *ce, int pos)
116{
117 if (ce_stage(ce) != 1 ||
118 active_nr <= pos + 2 ||
119 strcmp(active_cache[pos+1]->name, ce->name) ||
120 ce_stage(active_cache[pos+1]) != 2 ||
121 strcmp(active_cache[pos+2]->name, ce->name) ||
122 ce_stage(active_cache[pos+2]) != 3)
123 return error("path '%s' does not have all three versions",
124 ce->name);
125 return 0;
126}
127
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128static int checkout_stage(int stage, struct cache_entry *ce, int pos,
129 struct checkout *state)
130{
131 while (pos < active_nr &&
132 !strcmp(active_cache[pos]->name, ce->name)) {
133 if (ce_stage(active_cache[pos]) == stage)
134 return checkout_entry(active_cache[pos], state, NULL);
135 pos++;
136 }
137 return error("path '%s' does not have %s version",
138 ce->name,
139 (stage == 2) ? "our" : "their");
140}
8fdcf312 141
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142/* NEEDSWORK: share with merge-recursive */
143static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
144{
145 unsigned long size;
146 enum object_type type;
147
148 if (!hashcmp(sha1, null_sha1)) {
149 mm->ptr = xstrdup("");
150 mm->size = 0;
151 return;
152 }
153
154 mm->ptr = read_sha1_file(sha1, &type, &size);
155 if (!mm->ptr || type != OBJ_BLOB)
156 die("unable to read blob object %s", sha1_to_hex(sha1));
157 mm->size = size;
158}
159
160static int checkout_merged(int pos, struct checkout *state)
161{
162 struct cache_entry *ce = active_cache[pos];
163 const char *path = ce->name;
164 mmfile_t ancestor, ours, theirs;
165 int status;
166 unsigned char sha1[20];
167 mmbuffer_t result_buf;
168
169 if (ce_stage(ce) != 1 ||
170 active_nr <= pos + 2 ||
171 strcmp(active_cache[pos+1]->name, path) ||
172 ce_stage(active_cache[pos+1]) != 2 ||
173 strcmp(active_cache[pos+2]->name, path) ||
174 ce_stage(active_cache[pos+2]) != 3)
175 return error("path '%s' does not have all 3 versions", path);
176
177 fill_mm(active_cache[pos]->sha1, &ancestor);
178 fill_mm(active_cache[pos+1]->sha1, &ours);
179 fill_mm(active_cache[pos+2]->sha1, &theirs);
180
181 status = ll_merge(&result_buf, path, &ancestor,
182 &ours, "ours", &theirs, "theirs", 1);
183 free(ancestor.ptr);
184 free(ours.ptr);
185 free(theirs.ptr);
186 if (status < 0 || !result_buf.ptr) {
187 free(result_buf.ptr);
188 return error("path '%s': cannot merge", path);
189 }
190
191 /*
192 * NEEDSWORK:
193 * There is absolutely no reason to write this as a blob object
194 * and create a phoney cache entry just to leak. This hack is
195 * primarily to get to the write_entry() machinery that massages
196 * the contents to work-tree format and writes out which only
197 * allows it for a cache entry. The code in write_entry() needs
198 * to be refactored to allow us to feed a <buffer, size, mode>
199 * instead of a cache entry. Such a refactoring would help
200 * merge_recursive as well (it also writes the merge result to the
201 * object database even when it may contain conflicts).
202 */
203 if (write_sha1_file(result_buf.ptr, result_buf.size,
204 blob_type, sha1))
205 die("Unable to add merge result for '%s'", path);
206 ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
207 sha1,
208 path, 2, 0);
048f2762
DP
209 if (!ce)
210 die("make_cache_entry failed for path '%s'", path);
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211 status = checkout_entry(ce, state, NULL);
212 return status;
213}
8fdcf312 214
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215static int checkout_paths(struct tree *source_tree, const char **pathspec,
216 struct checkout_opts *opts)
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217{
218 int pos;
219 struct checkout state;
220 static char *ps_matched;
221 unsigned char rev[20];
222 int flag;
223 struct commit *head;
d2b3691b 224 int errs = 0;
38901a48 225 int stage = opts->writeout_stage;
0cf8581e 226 int merge = opts->merge;
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DB
227 int newfd;
228 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
229
230 newfd = hold_locked_index(lock_file, 1);
231 read_cache();
232
233 if (source_tree)
234 read_tree_some(source_tree, pathspec);
235
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236 for (pos = 0; pathspec[pos]; pos++)
237 ;
238 ps_matched = xcalloc(1, pos);
239
240 for (pos = 0; pos < active_nr; pos++) {
241 struct cache_entry *ce = active_cache[pos];
242 pathspec_match(pathspec, ps_matched, ce->name, 0);
243 }
244
245 if (report_path_error(ps_matched, pathspec, 0))
246 return 1;
247
8fdcf312
JH
248 /* Any unmerged paths? */
249 for (pos = 0; pos < active_nr; pos++) {
250 struct cache_entry *ce = active_cache[pos];
251 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
252 if (!ce_stage(ce))
253 continue;
db941099
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254 if (opts->force) {
255 warning("path '%s' is unmerged", ce->name);
38901a48
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256 } else if (stage) {
257 errs |= check_stage(stage, ce, pos);
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JH
258 } else if (opts->merge) {
259 errs |= check_all_stages(ce, pos);
db941099
JH
260 } else {
261 errs = 1;
262 error("path '%s' is unmerged", ce->name);
263 }
8fdcf312
JH
264 pos = skip_same_name(ce, pos) - 1;
265 }
266 }
267 if (errs)
268 return 1;
269
d2b3691b 270 /* Now we are committed to check them out */
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DB
271 memset(&state, 0, sizeof(state));
272 state.force = 1;
273 state.refresh_cache = 1;
274 for (pos = 0; pos < active_nr; pos++) {
275 struct cache_entry *ce = active_cache[pos];
276 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
8fdcf312
JH
277 if (!ce_stage(ce)) {
278 errs |= checkout_entry(ce, &state, NULL);
279 continue;
280 }
38901a48
JH
281 if (stage)
282 errs |= checkout_stage(stage, ce, pos, &state);
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JH
283 else if (merge)
284 errs |= checkout_merged(pos, &state);
8fdcf312 285 pos = skip_same_name(ce, pos) - 1;
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DB
286 }
287 }
288
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DB
289 if (write_cache(newfd, active_cache, active_nr) ||
290 commit_locked_index(lock_file))
291 die("unable to write new index file");
292
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DB
293 resolve_ref("HEAD", rev, 0, &flag);
294 head = lookup_commit_reference_gently(rev, 1);
295
d2b3691b
JH
296 errs |= post_checkout_hook(head, head, 0);
297 return errs;
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DB
298}
299
300static void show_local_changes(struct object *head)
301{
302 struct rev_info rev;
303 /* I think we want full paths, even if we're in a subdirectory. */
304 init_revisions(&rev, NULL);
305 rev.abbrev = 0;
306 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
307 add_pending_object(&rev, head, NULL);
308 run_diff_index(&rev, 0);
309}
310
311static void describe_detached_head(char *msg, struct commit *commit)
312{
313 struct strbuf sb;
314 strbuf_init(&sb, 0);
315 parse_commit(commit);
27886318 316 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
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DB
317 fprintf(stderr, "%s %s... %s\n", msg,
318 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
319 strbuf_release(&sb);
320}
321
6286a08d 322static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
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DB
323{
324 struct unpack_trees_options opts;
325 struct tree_desc tree_desc;
bc052d7f 326
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DB
327 memset(&opts, 0, sizeof(opts));
328 opts.head_idx = -1;
6286a08d
JH
329 opts.update = worktree;
330 opts.skip_unmerged = !worktree;
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DB
331 opts.reset = 1;
332 opts.merge = 1;
333 opts.fn = oneway_merge;
6286a08d 334 opts.verbose_update = !o->quiet;
34110cd4
LT
335 opts.src_index = &the_index;
336 opts.dst_index = &the_index;
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DB
337 parse_tree(tree);
338 init_tree_desc(&tree_desc, tree->buffer, tree->size);
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JH
339 switch (unpack_trees(1, &tree_desc, &opts)) {
340 case -2:
341 o->writeout_error = 1;
342 /*
343 * We return 0 nevertheless, as the index is all right
344 * and more importantly we have made best efforts to
345 * update paths in the work tree, and we cannot revert
346 * them.
347 */
348 case 0:
349 return 0;
350 default:
84a5750b 351 return 128;
291d823e 352 }
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DB
353}
354
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DB
355struct branch_info {
356 const char *name; /* The short name used */
357 const char *path; /* The full name of a real branch */
358 struct commit *commit; /* The named commit */
359};
360
361static void setup_branch_path(struct branch_info *branch)
362{
363 struct strbuf buf;
364 strbuf_init(&buf, 0);
365 strbuf_addstr(&buf, "refs/heads/");
366 strbuf_addstr(&buf, branch->name);
367 branch->path = strbuf_detach(&buf, NULL);
368}
369
370static int merge_working_tree(struct checkout_opts *opts,
75ea38df 371 struct branch_info *old, struct branch_info *new)
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DB
372{
373 int ret;
374 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
375 int newfd = hold_locked_index(lock_file, 1);
376 read_cache();
377
378 if (opts->force) {
6286a08d 379 ret = reset_tree(new->commit->tree, opts, 1);
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DB
380 if (ret)
381 return ret;
382 } else {
383 struct tree_desc trees[2];
384 struct tree *tree;
385 struct unpack_trees_options topts;
bc052d7f 386
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DB
387 memset(&topts, 0, sizeof(topts));
388 topts.head_idx = -1;
34110cd4
LT
389 topts.src_index = &the_index;
390 topts.dst_index = &the_index;
782c2d65 391
8ccba008
JH
392 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
393
782c2d65
DB
394 refresh_cache(REFRESH_QUIET);
395
396 if (unmerged_cache()) {
04c9e11f
JH
397 error("you need to resolve your current index first");
398 return 1;
782c2d65 399 }
04c9e11f
JH
400
401 /* 2-way merge to the new branch */
55218834
JH
402 topts.initial_checkout = (!active_nr &&
403 (old->commit == new->commit));
04c9e11f
JH
404 topts.update = 1;
405 topts.merge = 1;
406 topts.gently = opts->merge;
407 topts.verbose_update = !opts->quiet;
408 topts.fn = twoway_merge;
409 topts.dir = xcalloc(1, sizeof(*topts.dir));
410 topts.dir->show_ignored = 1;
411 topts.dir->exclude_per_dir = ".gitignore";
412 tree = parse_tree_indirect(old->commit->object.sha1);
413 init_tree_desc(&trees[0], tree->buffer, tree->size);
414 tree = parse_tree_indirect(new->commit->object.sha1);
415 init_tree_desc(&trees[1], tree->buffer, tree->size);
416
291d823e
JH
417 ret = unpack_trees(2, trees, &topts);
418 if (ret == -1) {
782c2d65
DB
419 /*
420 * Unpack couldn't do a trivial merge; either
421 * give up or do a real merge, depending on
422 * whether the merge flag was used.
423 */
424 struct tree *result;
425 struct tree *work;
8a2fce18 426 struct merge_options o;
782c2d65
DB
427 if (!opts->merge)
428 return 1;
429 parse_commit(old->commit);
430
431 /* Do more real merge */
432
433 /*
434 * We update the index fully, then write the
435 * tree from the index, then merge the new
436 * branch with the current tree, with the old
437 * branch as the base. Then we reset the index
438 * (but not the working tree) to the new
439 * branch, leaving the working tree as the
440 * merged version, but skipping unmerged
441 * entries in the index.
442 */
443
7ae02a30 444 add_files_to_cache(NULL, NULL, 0);
8a2fce18
MV
445 init_merge_options(&o);
446 o.verbosity = 0;
447 work = write_tree_from_memory(&o);
782c2d65 448
6286a08d 449 ret = reset_tree(new->commit->tree, opts, 1);
782c2d65
DB
450 if (ret)
451 return ret;
8a2fce18
MV
452 o.branch1 = new->name;
453 o.branch2 = "local";
454 merge_trees(&o, new->commit->tree, work,
455 old->commit->tree, &result);
6286a08d 456 ret = reset_tree(new->commit->tree, opts, 0);
84a5750b
JH
457 if (ret)
458 return ret;
782c2d65
DB
459 }
460 }
461
462 if (write_cache(newfd, active_cache, active_nr) ||
463 commit_locked_index(lock_file))
464 die("unable to write new index file");
465
7fe4a728 466 if (!opts->force && !opts->quiet)
782c2d65
DB
467 show_local_changes(&new->commit->object);
468
469 return 0;
470}
471
6d21bf96 472static void report_tracking(struct branch_info *new)
79a1e6b4 473{
6d21bf96 474 struct strbuf sb = STRBUF_INIT;
b56fca07 475 struct branch *branch = branch_get(new->name);
79a1e6b4 476
6d21bf96 477 if (!format_tracking_info(branch, &sb))
79a1e6b4 478 return;
6d21bf96
JH
479 fputs(sb.buf, stdout);
480 strbuf_release(&sb);
b0030db3 481}
79a1e6b4 482
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DB
483static void update_refs_for_switch(struct checkout_opts *opts,
484 struct branch_info *old,
485 struct branch_info *new)
486{
487 struct strbuf msg;
488 const char *old_desc;
489 if (opts->new_branch) {
490 create_branch(old->name, opts->new_branch, new->name, 0,
491 opts->new_branch_log, opts->track);
492 new->name = opts->new_branch;
493 setup_branch_path(new);
494 }
495
496 strbuf_init(&msg, 0);
497 old_desc = old->name;
498 if (!old_desc)
499 old_desc = sha1_to_hex(old->commit->object.sha1);
500 strbuf_addf(&msg, "checkout: moving from %s to %s",
501 old_desc, new->name);
502
503 if (new->path) {
504 create_symref("HEAD", new->path, msg.buf);
505 if (!opts->quiet) {
506 if (old->path && !strcmp(new->path, old->path))
507 fprintf(stderr, "Already on \"%s\"\n",
508 new->name);
509 else
510 fprintf(stderr, "Switched to%s branch \"%s\"\n",
511 opts->new_branch ? " a new" : "",
512 new->name);
513 }
514 } else if (strcmp(new->name, "HEAD")) {
515 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
516 REF_NODEREF, DIE_ON_ERR);
517 if (!opts->quiet) {
518 if (old->path)
519 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);
520 describe_detached_head("HEAD is now at", new->commit);
521 }
522 }
523 remove_branch_state();
524 strbuf_release(&msg);
b0030db3 525 if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
6d21bf96 526 report_tracking(new);
782c2d65
DB
527}
528
75ea38df 529static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
782c2d65
DB
530{
531 int ret = 0;
532 struct branch_info old;
533 unsigned char rev[20];
534 int flag;
535 memset(&old, 0, sizeof(old));
536 old.path = resolve_ref("HEAD", rev, 0, &flag);
537 old.commit = lookup_commit_reference_gently(rev, 1);
538 if (!(flag & REF_ISSYMREF))
539 old.path = NULL;
540
541 if (old.path && !prefixcmp(old.path, "refs/heads/"))
542 old.name = old.path + strlen("refs/heads/");
543
544 if (!new->name) {
545 new->name = "HEAD";
546 new->commit = old.commit;
547 if (!new->commit)
548 die("You are on a branch yet to be born");
549 parse_commit(new->commit);
550 }
551
552 /*
bea005e2
JK
553 * If we were on a detached HEAD, but we are now moving to
554 * a new commit, we want to mention the old commit once more
555 * to remind the user that it might be lost.
782c2d65 556 */
bea005e2 557 if (!opts->quiet && !old.path && new->commit != old.commit)
782c2d65
DB
558 describe_detached_head("Previous HEAD position was", old.commit);
559
560 if (!old.commit) {
561 if (!opts->quiet) {
562 fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
563 fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
564 }
565 opts->force = 1;
566 }
567
75ea38df 568 ret = merge_working_tree(opts, &old, new);
782c2d65
DB
569 if (ret)
570 return ret;
571
572 update_refs_for_switch(opts, &old, new);
573
291d823e
JH
574 ret = post_checkout_hook(old.commit, new->commit, 1);
575 return ret || opts->writeout_error;
782c2d65
DB
576}
577
0cf8581e
JH
578static int git_checkout_config(const char *var, const char *value, void *cb)
579{
580 return git_xmerge_config(var, value, cb);
581}
582
782c2d65
DB
583int cmd_checkout(int argc, const char **argv, const char *prefix)
584{
585 struct checkout_opts opts;
586 unsigned char rev[20];
587 const char *arg;
588 struct branch_info new;
589 struct tree *source_tree = NULL;
eac5a401 590 char *conflict_style = NULL;
782c2d65
DB
591 struct option options[] = {
592 OPT__QUIET(&opts.quiet),
593 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
594 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
498a6e7e 595 OPT_SET_INT('t', "track", &opts.track, "track",
9ed36cfa 596 BRANCH_TRACK_EXPLICIT),
38901a48
JH
597 OPT_SET_INT('2', "ours", &opts.writeout_stage, "stage",
598 2),
599 OPT_SET_INT('3', "theirs", &opts.writeout_stage, "stage",
600 3),
782c2d65 601 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
eac5a401
JH
602 OPT_BOOLEAN('m', "merge", &opts.merge, "merge"),
603 OPT_STRING(0, "conflict", &conflict_style, "style",
604 "conflict style (merge or diff3)"),
b249b552 605 OPT_END(),
782c2d65 606 };
859fdaba 607 int has_dash_dash;
782c2d65
DB
608
609 memset(&opts, 0, sizeof(opts));
610 memset(&new, 0, sizeof(new));
611
0cf8581e 612 git_config(git_checkout_config, NULL);
782c2d65 613
9188ed89 614 opts.track = BRANCH_TRACK_UNSPECIFIED;
782c2d65 615
f5242ebf
PH
616 argc = parse_options(argc, argv, options, checkout_usage,
617 PARSE_OPT_KEEP_DASHDASH);
859fdaba 618
bb0ceb62 619 /* --track without -b should DWIM */
9188ed89
AR
620 if (0 < opts.track && !opts.new_branch) {
621 const char *argv0 = argv[0];
622 if (!argc || !strcmp(argv0, "--"))
bb0ceb62 623 die ("--track needs a branch name");
9188ed89
AR
624 if (!prefixcmp(argv0, "refs/"))
625 argv0 += 5;
626 if (!prefixcmp(argv0, "remotes/"))
627 argv0 += 8;
628 argv0 = strchr(argv0, '/');
629 if (!argv0 || !argv0[1])
bb0ceb62 630 die ("Missing branch name; try -b");
9188ed89 631 opts.new_branch = argv0 + 1;
bb0ceb62
JS
632 }
633
9188ed89 634 if (opts.track == BRANCH_TRACK_UNSPECIFIED)
bb0ceb62 635 opts.track = git_branch_track;
eac5a401
JH
636 if (conflict_style) {
637 opts.merge = 1; /* implied */
638 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
639 }
640
859fdaba
PH
641 if (!opts.new_branch && (opts.track != git_branch_track))
642 die("git checkout: --track and --no-track require -b");
643
644 if (opts.force && opts.merge)
645 die("git checkout: -f and -m are incompatible");
646
647 /*
648 * case 1: git checkout <ref> -- [<paths>]
649 *
650 * <ref> must be a valid tree, everything after the '--' must be
651 * a path.
652 *
653 * case 2: git checkout -- [<paths>]
654 *
655 * everything after the '--' must be paths.
656 *
657 * case 3: git checkout <something> [<paths>]
658 *
659 * With no paths, if <something> is a commit, that is to
660 * switch to the branch or detach HEAD at it.
661 *
662 * Otherwise <something> shall not be ambiguous.
663 * - If it's *only* a reference, treat it like case (1).
664 * - If it's only a path, treat it like case (2).
665 * - else: fail.
666 *
667 */
782c2d65 668 if (argc) {
859fdaba
PH
669 if (!strcmp(argv[0], "--")) { /* case (2) */
670 argv++;
671 argc--;
672 goto no_reference;
673 }
674
782c2d65 675 arg = argv[0];
859fdaba
PH
676 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
677
678 if (get_sha1(arg, rev)) {
679 if (has_dash_dash) /* case (1) */
680 die("invalid reference: %s", arg);
681 goto no_reference; /* case (3 -> 2) */
682 }
683
684 /* we can't end up being in (2) anymore, eat the argument */
685 argv++;
686 argc--;
687
688 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
782c2d65
DB
689 new.name = arg;
690 setup_branch_path(&new);
691 if (resolve_ref(new.path, rev, 1, NULL))
692 new.commit = lookup_commit_reference(rev);
693 else
694 new.path = NULL;
695 parse_commit(new.commit);
696 source_tree = new.commit->tree;
859fdaba
PH
697 } else
698 source_tree = parse_tree_indirect(rev);
699
700 if (!source_tree) /* case (1): want a tree */
701 die("reference is not a tree: %s", arg);
702 if (!has_dash_dash) {/* case (3 -> 1) */
703 /*
704 * Do not complain the most common case
705 * git checkout branch
706 * even if there happen to be a file called 'branch';
707 * it would be extremely annoying.
708 */
709 if (argc)
710 verify_non_filename(NULL, arg);
711 }
712 else {
782c2d65
DB
713 argv++;
714 argc--;
715 }
716 }
717
859fdaba 718no_reference:
782c2d65
DB
719 if (argc) {
720 const char **pathspec = get_pathspec(prefix, argv);
301e42ed
AR
721
722 if (!pathspec)
723 die("invalid path specification");
724
782c2d65 725 /* Checkout paths */
0cf8581e 726 if (opts.new_branch) {
782c2d65 727 if (argc == 1) {
db941099 728 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 729 } else {
db941099 730 die("git checkout: updating paths is incompatible with switching branches.");
782c2d65
DB
731 }
732 }
733
0cf8581e
JH
734 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
735 die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");
736
db941099 737 return checkout_paths(source_tree, pathspec, &opts);
782c2d65
DB
738 }
739
352eadc4
DB
740 if (opts.new_branch) {
741 struct strbuf buf;
742 strbuf_init(&buf, 0);
743 strbuf_addstr(&buf, "refs/heads/");
744 strbuf_addstr(&buf, opts.new_branch);
745 if (!get_sha1(buf.buf, rev))
746 die("git checkout: branch %s already exists", opts.new_branch);
747 if (check_ref_format(buf.buf))
748 die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);
749 strbuf_release(&buf);
750 }
751
782c2d65
DB
752 if (new.name && !new.commit) {
753 die("Cannot switch branch to a non-commit.");
754 }
38901a48
JH
755 if (opts.writeout_stage)
756 die("--ours/--theirs is incompatible with switching branches.");
782c2d65 757
75ea38df 758 return switch_branches(&opts, &new);
782c2d65 759}