93ea69bfaa083f49a6e808c7317ea1910b29c847
[git/git.git] / builtin-checkout.c
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"
15 #include "remote.h"
16
17 static const char * const checkout_usage[] = {
18 "git checkout [options] <branch>",
19 "git checkout [options] [<branch>] -- <file>...",
20 NULL,
21 };
22
23 static int post_checkout_hook(struct commit *old, struct commit *new,
24 int changed)
25 {
26 struct child_process proc;
27 const char *name = git_path("hooks/post-checkout");
28 const char *argv[5];
29
30 if (access(name, X_OK) < 0)
31 return 0;
32
33 memset(&proc, 0, sizeof(proc));
34 argv[0] = name;
35 argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
36 argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
37 argv[3] = changed ? "1" : "0";
38 argv[4] = NULL;
39 proc.argv = argv;
40 proc.no_stdin = 1;
41 proc.stdout_to_stderr = 1;
42 return run_command(&proc);
43 }
44
45 static int update_some(const unsigned char *sha1, const char *base, int baselen,
46 const char *pathname, unsigned mode, int stage)
47 {
48 int len;
49 struct cache_entry *ce;
50
51 if (S_ISGITLINK(mode))
52 return 0;
53
54 if (S_ISDIR(mode))
55 return READ_TREE_RECURSIVE;
56
57 len = baselen + strlen(pathname);
58 ce = xcalloc(1, cache_entry_size(len));
59 hashcpy(ce->sha1, sha1);
60 memcpy(ce->name, base, baselen);
61 memcpy(ce->name + baselen, pathname, len - baselen);
62 ce->ce_flags = create_ce_flags(len, 0);
63 ce->ce_mode = create_ce_mode(mode);
64 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
65 return 0;
66 }
67
68 static int read_tree_some(struct tree *tree, const char **pathspec)
69 {
70 read_tree_recursive(tree, "", 0, 0, pathspec, update_some);
71
72 /* update the index with the given tree's info
73 * for all args, expanding wildcards, and exit
74 * with any non-zero return code.
75 */
76 return 0;
77 }
78
79 static int checkout_paths(struct tree *source_tree, const char **pathspec)
80 {
81 int pos;
82 struct checkout state;
83 static char *ps_matched;
84 unsigned char rev[20];
85 int flag;
86 struct commit *head;
87 int errs = 0;
88
89 int newfd;
90 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
91
92 newfd = hold_locked_index(lock_file, 1);
93 read_cache();
94
95 if (source_tree)
96 read_tree_some(source_tree, pathspec);
97
98 for (pos = 0; pathspec[pos]; pos++)
99 ;
100 ps_matched = xcalloc(1, pos);
101
102 for (pos = 0; pos < active_nr; pos++) {
103 struct cache_entry *ce = active_cache[pos];
104 pathspec_match(pathspec, ps_matched, ce->name, 0);
105 }
106
107 if (report_path_error(ps_matched, pathspec, 0))
108 return 1;
109
110 /* Now we are committed to check them out */
111 memset(&state, 0, sizeof(state));
112 state.force = 1;
113 state.refresh_cache = 1;
114 for (pos = 0; pos < active_nr; pos++) {
115 struct cache_entry *ce = active_cache[pos];
116 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
117 errs |= checkout_entry(ce, &state, NULL);
118 }
119 }
120
121 if (write_cache(newfd, active_cache, active_nr) ||
122 commit_locked_index(lock_file))
123 die("unable to write new index file");
124
125 resolve_ref("HEAD", rev, 0, &flag);
126 head = lookup_commit_reference_gently(rev, 1);
127
128 errs |= post_checkout_hook(head, head, 0);
129 return errs;
130 }
131
132 static void show_local_changes(struct object *head)
133 {
134 struct rev_info rev;
135 /* I think we want full paths, even if we're in a subdirectory. */
136 init_revisions(&rev, NULL);
137 rev.abbrev = 0;
138 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
139 add_pending_object(&rev, head, NULL);
140 run_diff_index(&rev, 0);
141 }
142
143 static void describe_detached_head(char *msg, struct commit *commit)
144 {
145 struct strbuf sb;
146 strbuf_init(&sb, 0);
147 parse_commit(commit);
148 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
149 fprintf(stderr, "%s %s... %s\n", msg,
150 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
151 strbuf_release(&sb);
152 }
153
154 struct checkout_opts {
155 int quiet;
156 int merge;
157 int force;
158 int writeout_error;
159
160 char *new_branch;
161 int new_branch_log;
162 enum branch_track track;
163 };
164
165 static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
166 {
167 struct unpack_trees_options opts;
168 struct tree_desc tree_desc;
169
170 memset(&opts, 0, sizeof(opts));
171 opts.head_idx = -1;
172 opts.update = worktree;
173 opts.skip_unmerged = !worktree;
174 opts.reset = 1;
175 opts.merge = 1;
176 opts.fn = oneway_merge;
177 opts.verbose_update = !o->quiet;
178 opts.src_index = &the_index;
179 opts.dst_index = &the_index;
180 parse_tree(tree);
181 init_tree_desc(&tree_desc, tree->buffer, tree->size);
182 switch (unpack_trees(1, &tree_desc, &opts)) {
183 case -2:
184 o->writeout_error = 1;
185 /*
186 * We return 0 nevertheless, as the index is all right
187 * and more importantly we have made best efforts to
188 * update paths in the work tree, and we cannot revert
189 * them.
190 */
191 case 0:
192 return 0;
193 default:
194 return 128;
195 }
196 }
197
198 struct branch_info {
199 const char *name; /* The short name used */
200 const char *path; /* The full name of a real branch */
201 struct commit *commit; /* The named commit */
202 };
203
204 static void setup_branch_path(struct branch_info *branch)
205 {
206 struct strbuf buf;
207 strbuf_init(&buf, 0);
208 strbuf_addstr(&buf, "refs/heads/");
209 strbuf_addstr(&buf, branch->name);
210 branch->path = strbuf_detach(&buf, NULL);
211 }
212
213 static int merge_working_tree(struct checkout_opts *opts,
214 struct branch_info *old, struct branch_info *new)
215 {
216 int ret;
217 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
218 int newfd = hold_locked_index(lock_file, 1);
219 read_cache();
220
221 if (opts->force) {
222 ret = reset_tree(new->commit->tree, opts, 1);
223 if (ret)
224 return ret;
225 } else {
226 struct tree_desc trees[2];
227 struct tree *tree;
228 struct unpack_trees_options topts;
229
230 memset(&topts, 0, sizeof(topts));
231 topts.head_idx = -1;
232 topts.src_index = &the_index;
233 topts.dst_index = &the_index;
234
235 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
236
237 refresh_cache(REFRESH_QUIET);
238
239 if (unmerged_cache()) {
240 error("you need to resolve your current index first");
241 return 1;
242 }
243
244 /* 2-way merge to the new branch */
245 topts.update = 1;
246 topts.merge = 1;
247 topts.gently = opts->merge;
248 topts.verbose_update = !opts->quiet;
249 topts.fn = twoway_merge;
250 topts.dir = xcalloc(1, sizeof(*topts.dir));
251 topts.dir->show_ignored = 1;
252 topts.dir->exclude_per_dir = ".gitignore";
253 tree = parse_tree_indirect(old->commit->object.sha1);
254 init_tree_desc(&trees[0], tree->buffer, tree->size);
255 tree = parse_tree_indirect(new->commit->object.sha1);
256 init_tree_desc(&trees[1], tree->buffer, tree->size);
257
258 ret = unpack_trees(2, trees, &topts);
259 if (ret == -1) {
260 /*
261 * Unpack couldn't do a trivial merge; either
262 * give up or do a real merge, depending on
263 * whether the merge flag was used.
264 */
265 struct tree *result;
266 struct tree *work;
267 if (!opts->merge)
268 return 1;
269 parse_commit(old->commit);
270
271 /* Do more real merge */
272
273 /*
274 * We update the index fully, then write the
275 * tree from the index, then merge the new
276 * branch with the current tree, with the old
277 * branch as the base. Then we reset the index
278 * (but not the working tree) to the new
279 * branch, leaving the working tree as the
280 * merged version, but skipping unmerged
281 * entries in the index.
282 */
283
284 add_files_to_cache(NULL, NULL, 0);
285 work = write_tree_from_memory();
286
287 ret = reset_tree(new->commit->tree, opts, 1);
288 if (ret)
289 return ret;
290 merge_trees(new->commit->tree, work, old->commit->tree,
291 new->name, "local", &result);
292 ret = reset_tree(new->commit->tree, opts, 0);
293 if (ret)
294 return ret;
295 }
296 }
297
298 if (write_cache(newfd, active_cache, active_nr) ||
299 commit_locked_index(lock_file))
300 die("unable to write new index file");
301
302 if (!opts->force)
303 show_local_changes(&new->commit->object);
304
305 return 0;
306 }
307
308 static void report_tracking(struct branch_info *new, struct checkout_opts *opts)
309 {
310 /*
311 * We have switched to a new branch; is it building on
312 * top of another branch, and if so does that other branch
313 * have changes we do not have yet?
314 */
315 char *base;
316 unsigned char sha1[20];
317 struct commit *ours, *theirs;
318 char symmetric[84];
319 struct rev_info revs;
320 const char *rev_argv[10];
321 int rev_argc;
322 int num_ours, num_theirs;
323 const char *remote_msg;
324 struct branch *branch = branch_get(new->name);
325
326 /*
327 * Nothing to report unless we are marked to build on top of
328 * somebody else.
329 */
330 if (!branch || !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
331 return;
332
333 /*
334 * If what we used to build on no longer exists, there is
335 * nothing to report.
336 */
337 base = branch->merge[0]->dst;
338 if (!resolve_ref(base, sha1, 1, NULL))
339 return;
340
341 theirs = lookup_commit(sha1);
342 ours = new->commit;
343 if (!hashcmp(sha1, ours->object.sha1))
344 return; /* we are the same */
345
346 /* Run "rev-list --left-right ours...theirs" internally... */
347 rev_argc = 0;
348 rev_argv[rev_argc++] = NULL;
349 rev_argv[rev_argc++] = "--left-right";
350 rev_argv[rev_argc++] = symmetric;
351 rev_argv[rev_argc++] = "--";
352 rev_argv[rev_argc] = NULL;
353
354 strcpy(symmetric, sha1_to_hex(ours->object.sha1));
355 strcpy(symmetric + 40, "...");
356 strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
357
358 init_revisions(&revs, NULL);
359 setup_revisions(rev_argc, rev_argv, &revs, NULL);
360 prepare_revision_walk(&revs);
361
362 /* ... and count the commits on each side. */
363 num_ours = 0;
364 num_theirs = 0;
365 while (1) {
366 struct commit *c = get_revision(&revs);
367 if (!c)
368 break;
369 if (c->object.flags & SYMMETRIC_LEFT)
370 num_ours++;
371 else
372 num_theirs++;
373 }
374
375 if (!prefixcmp(base, "refs/remotes/")) {
376 remote_msg = " remote";
377 base += strlen("refs/remotes/");
378 } else {
379 remote_msg = "";
380 }
381
382 if (!num_theirs)
383 printf("Your branch is ahead of the tracked%s branch '%s' "
384 "by %d commit%s.\n",
385 remote_msg, base,
386 num_ours, (num_ours == 1) ? "" : "s");
387 else if (!num_ours)
388 printf("Your branch is behind the tracked%s branch '%s' "
389 "by %d commit%s,\n"
390 "and can be fast-forwarded.\n",
391 remote_msg, base,
392 num_theirs, (num_theirs == 1) ? "" : "s");
393 else
394 printf("Your branch and the tracked%s branch '%s' "
395 "have diverged,\nand respectively "
396 "have %d and %d different commit(s) each.\n",
397 remote_msg, base,
398 num_ours, num_theirs);
399 }
400
401 static void update_refs_for_switch(struct checkout_opts *opts,
402 struct branch_info *old,
403 struct branch_info *new)
404 {
405 struct strbuf msg;
406 const char *old_desc;
407 if (opts->new_branch) {
408 create_branch(old->name, opts->new_branch, new->name, 0,
409 opts->new_branch_log, opts->track);
410 new->name = opts->new_branch;
411 setup_branch_path(new);
412 }
413
414 strbuf_init(&msg, 0);
415 old_desc = old->name;
416 if (!old_desc)
417 old_desc = sha1_to_hex(old->commit->object.sha1);
418 strbuf_addf(&msg, "checkout: moving from %s to %s",
419 old_desc, new->name);
420
421 if (new->path) {
422 create_symref("HEAD", new->path, msg.buf);
423 if (!opts->quiet) {
424 if (old->path && !strcmp(new->path, old->path))
425 fprintf(stderr, "Already on \"%s\"\n",
426 new->name);
427 else
428 fprintf(stderr, "Switched to%s branch \"%s\"\n",
429 opts->new_branch ? " a new" : "",
430 new->name);
431 }
432 } else if (strcmp(new->name, "HEAD")) {
433 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
434 REF_NODEREF, DIE_ON_ERR);
435 if (!opts->quiet) {
436 if (old->path)
437 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);
438 describe_detached_head("HEAD is now at", new->commit);
439 }
440 }
441 remove_branch_state();
442 strbuf_release(&msg);
443 if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
444 report_tracking(new, opts);
445 }
446
447 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
448 {
449 int ret = 0;
450 struct branch_info old;
451 unsigned char rev[20];
452 int flag;
453 memset(&old, 0, sizeof(old));
454 old.path = resolve_ref("HEAD", rev, 0, &flag);
455 old.commit = lookup_commit_reference_gently(rev, 1);
456 if (!(flag & REF_ISSYMREF))
457 old.path = NULL;
458
459 if (old.path && !prefixcmp(old.path, "refs/heads/"))
460 old.name = old.path + strlen("refs/heads/");
461
462 if (!new->name) {
463 new->name = "HEAD";
464 new->commit = old.commit;
465 if (!new->commit)
466 die("You are on a branch yet to be born");
467 parse_commit(new->commit);
468 }
469
470 /*
471 * If the new thing isn't a branch and isn't HEAD and we're
472 * not starting a new branch, and we want messages, and we
473 * weren't on a branch, and we're moving to a new commit,
474 * describe the old commit.
475 */
476 if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
477 !opts->quiet && !old.path && new->commit != old.commit)
478 describe_detached_head("Previous HEAD position was", old.commit);
479
480 if (!old.commit) {
481 if (!opts->quiet) {
482 fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
483 fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
484 }
485 opts->force = 1;
486 }
487
488 ret = merge_working_tree(opts, &old, new);
489 if (ret)
490 return ret;
491
492 update_refs_for_switch(opts, &old, new);
493
494 ret = post_checkout_hook(old.commit, new->commit, 1);
495 return ret || opts->writeout_error;
496 }
497
498 int cmd_checkout(int argc, const char **argv, const char *prefix)
499 {
500 struct checkout_opts opts;
501 unsigned char rev[20];
502 const char *arg;
503 struct branch_info new;
504 struct tree *source_tree = NULL;
505 struct option options[] = {
506 OPT__QUIET(&opts.quiet),
507 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
508 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
509 OPT_SET_INT('t', "track", &opts.track, "track",
510 BRANCH_TRACK_EXPLICIT),
511 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
512 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
513 OPT_END(),
514 };
515
516 memset(&opts, 0, sizeof(opts));
517 memset(&new, 0, sizeof(new));
518
519 git_config(git_default_config, NULL);
520
521 opts.track = git_branch_track;
522
523 argc = parse_options(argc, argv, options, checkout_usage, 0);
524 if (argc) {
525 arg = argv[0];
526 if (get_sha1(arg, rev))
527 ;
528 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
529 new.name = arg;
530 setup_branch_path(&new);
531 if (resolve_ref(new.path, rev, 1, NULL))
532 new.commit = lookup_commit_reference(rev);
533 else
534 new.path = NULL;
535 parse_commit(new.commit);
536 source_tree = new.commit->tree;
537 argv++;
538 argc--;
539 } else if ((source_tree = parse_tree_indirect(rev))) {
540 argv++;
541 argc--;
542 }
543 }
544
545 if (argc && !strcmp(argv[0], "--")) {
546 argv++;
547 argc--;
548 }
549
550 if (!opts.new_branch && (opts.track != git_branch_track))
551 die("git checkout: --track and --no-track require -b");
552
553 if (opts.force && opts.merge)
554 die("git checkout: -f and -m are incompatible");
555
556 if (argc) {
557 const char **pathspec = get_pathspec(prefix, argv);
558
559 if (!pathspec)
560 die("invalid path specification");
561
562 /* Checkout paths */
563 if (opts.new_branch || opts.force || opts.merge) {
564 if (argc == 1) {
565 die("git checkout: updating paths is incompatible with switching branches/forcing\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
566 } else {
567 die("git checkout: updating paths is incompatible with switching branches/forcing");
568 }
569 }
570
571 return checkout_paths(source_tree, pathspec);
572 }
573
574 if (new.name && !new.commit) {
575 die("Cannot switch branch to a non-commit.");
576 }
577
578 return switch_branches(&opts, &new);
579 }