doc: documentation update for the branch track changes
[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 int newfd;
71 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
72 newfd = hold_locked_index(lock_file, 1);
73 read_cache();
74
75 read_tree_recursive(tree, "", 0, 0, pathspec, update_some);
76
77 if (write_cache(newfd, active_cache, active_nr) ||
78 commit_locked_index(lock_file))
79 die("unable to write new index file");
80
81 /* update the index with the given tree's info
82 * for all args, expanding wildcards, and exit
83 * with any non-zero return code.
84 */
85 return 0;
86 }
87
88 static int checkout_paths(const char **pathspec)
89 {
90 int pos;
91 struct checkout state;
92 static char *ps_matched;
93 unsigned char rev[20];
94 int flag;
95 struct commit *head;
96
97 for (pos = 0; pathspec[pos]; pos++)
98 ;
99 ps_matched = xcalloc(1, pos);
100
101 for (pos = 0; pos < active_nr; pos++) {
102 struct cache_entry *ce = active_cache[pos];
103 pathspec_match(pathspec, ps_matched, ce->name, 0);
104 }
105
106 if (report_path_error(ps_matched, pathspec, 0))
107 return 1;
108
109 memset(&state, 0, sizeof(state));
110 state.force = 1;
111 state.refresh_cache = 1;
112 for (pos = 0; pos < active_nr; pos++) {
113 struct cache_entry *ce = active_cache[pos];
114 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
115 checkout_entry(ce, &state, NULL);
116 }
117 }
118
119 resolve_ref("HEAD", rev, 0, &flag);
120 head = lookup_commit_reference_gently(rev, 1);
121
122 return post_checkout_hook(head, head, 0);
123 }
124
125 static void show_local_changes(struct object *head)
126 {
127 struct rev_info rev;
128 /* I think we want full paths, even if we're in a subdirectory. */
129 init_revisions(&rev, NULL);
130 rev.abbrev = 0;
131 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
132 add_pending_object(&rev, head, NULL);
133 run_diff_index(&rev, 0);
134 }
135
136 static void describe_detached_head(char *msg, struct commit *commit)
137 {
138 struct strbuf sb;
139 strbuf_init(&sb, 0);
140 parse_commit(commit);
141 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, "", "", 0, 0);
142 fprintf(stderr, "%s %s... %s\n", msg,
143 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
144 strbuf_release(&sb);
145 }
146
147 static int reset_to_new(struct tree *tree, int quiet)
148 {
149 struct unpack_trees_options opts;
150 struct tree_desc tree_desc;
151 memset(&opts, 0, sizeof(opts));
152 opts.head_idx = -1;
153 opts.update = 1;
154 opts.reset = 1;
155 opts.merge = 1;
156 opts.fn = oneway_merge;
157 opts.verbose_update = !quiet;
158 parse_tree(tree);
159 init_tree_desc(&tree_desc, tree->buffer, tree->size);
160 if (unpack_trees(1, &tree_desc, &opts))
161 return 128;
162 return 0;
163 }
164
165 static void reset_clean_to_new(struct tree *tree, int quiet)
166 {
167 struct unpack_trees_options opts;
168 struct tree_desc tree_desc;
169 memset(&opts, 0, sizeof(opts));
170 opts.head_idx = -1;
171 opts.skip_unmerged = 1;
172 opts.reset = 1;
173 opts.merge = 1;
174 opts.fn = oneway_merge;
175 opts.verbose_update = !quiet;
176 parse_tree(tree);
177 init_tree_desc(&tree_desc, tree->buffer, tree->size);
178 if (unpack_trees(1, &tree_desc, &opts))
179 exit(128);
180 }
181
182 struct checkout_opts {
183 int quiet;
184 int merge;
185 int force;
186
187 char *new_branch;
188 int new_branch_log;
189 enum branch_track track;
190 };
191
192 struct branch_info {
193 const char *name; /* The short name used */
194 const char *path; /* The full name of a real branch */
195 struct commit *commit; /* The named commit */
196 };
197
198 static void setup_branch_path(struct branch_info *branch)
199 {
200 struct strbuf buf;
201 strbuf_init(&buf, 0);
202 strbuf_addstr(&buf, "refs/heads/");
203 strbuf_addstr(&buf, branch->name);
204 branch->path = strbuf_detach(&buf, NULL);
205 }
206
207 static int merge_working_tree(struct checkout_opts *opts,
208 struct branch_info *old, struct branch_info *new,
209 const char *prefix)
210 {
211 int ret;
212 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
213 int newfd = hold_locked_index(lock_file, 1);
214 read_cache();
215
216 if (opts->force) {
217 ret = reset_to_new(new->commit->tree, opts->quiet);
218 if (ret)
219 return ret;
220 } else {
221 struct tree_desc trees[2];
222 struct tree *tree;
223 struct unpack_trees_options topts;
224 memset(&topts, 0, sizeof(topts));
225 topts.head_idx = -1;
226
227 refresh_cache(REFRESH_QUIET);
228
229 if (unmerged_cache()) {
230 ret = opts->merge ? -1 :
231 error("you need to resolve your current index first");
232 } else {
233 topts.update = 1;
234 topts.merge = 1;
235 topts.gently = opts->merge;
236 topts.fn = twoway_merge;
237 topts.dir = xcalloc(1, sizeof(*topts.dir));
238 topts.dir->show_ignored = 1;
239 topts.dir->exclude_per_dir = ".gitignore";
240 topts.prefix = prefix;
241 tree = parse_tree_indirect(old->commit->object.sha1);
242 init_tree_desc(&trees[0], tree->buffer, tree->size);
243 tree = parse_tree_indirect(new->commit->object.sha1);
244 init_tree_desc(&trees[1], tree->buffer, tree->size);
245 ret = unpack_trees(2, trees, &topts);
246 }
247 if (ret) {
248 /*
249 * Unpack couldn't do a trivial merge; either
250 * give up or do a real merge, depending on
251 * whether the merge flag was used.
252 */
253 struct tree *result;
254 struct tree *work;
255 if (!opts->merge)
256 return 1;
257 parse_commit(old->commit);
258
259 /* Do more real merge */
260
261 /*
262 * We update the index fully, then write the
263 * tree from the index, then merge the new
264 * branch with the current tree, with the old
265 * branch as the base. Then we reset the index
266 * (but not the working tree) to the new
267 * branch, leaving the working tree as the
268 * merged version, but skipping unmerged
269 * entries in the index.
270 */
271
272 add_files_to_cache(0, NULL, NULL);
273 work = write_tree_from_memory();
274
275 ret = reset_to_new(new->commit->tree, opts->quiet);
276 if (ret)
277 return ret;
278 merge_trees(new->commit->tree, work, old->commit->tree,
279 new->name, "local", &result);
280 reset_clean_to_new(new->commit->tree, opts->quiet);
281 }
282 }
283
284 if (write_cache(newfd, active_cache, active_nr) ||
285 commit_locked_index(lock_file))
286 die("unable to write new index file");
287
288 if (!opts->force)
289 show_local_changes(&new->commit->object);
290
291 return 0;
292 }
293
294 static void adjust_to_tracking(struct branch_info *new, struct checkout_opts *opts)
295 {
296 /*
297 * We have switched to a new branch; is it building on
298 * top of another branch, and if so does that other branch
299 * have changes we do not have yet?
300 */
301 char *base;
302 unsigned char sha1[20];
303 struct commit *ours, *theirs;
304 const char *msgfmt;
305 char symmetric[84];
306 int show_log;
307 struct branch *branch = branch_get(NULL);
308
309 if (!branch || !branch->merge)
310 return;
311
312 base = branch->merge[0]->dst;
313
314 ours = new->commit;
315
316 sprintf(symmetric, "%s", sha1_to_hex(ours->object.sha1));
317
318 /*
319 * Ok, it is tracking base; is it ahead of us?
320 */
321 if (!resolve_ref(base, sha1, 1, NULL))
322 return;
323 theirs = lookup_commit(sha1);
324
325 sprintf(symmetric + 40, "...%s", sha1_to_hex(sha1));
326
327 if (!hashcmp(sha1, ours->object.sha1))
328 return; /* we are the same */
329
330 show_log = 1;
331 if (in_merge_bases(theirs, &ours, 1)) {
332 msgfmt = "You are ahead of the tracked branch '%s'\n";
333 show_log = 0;
334 }
335 else if (in_merge_bases(ours, &theirs, 1))
336 msgfmt = "Your branch can be fast-forwarded to the tracked branch '%s'\n";
337 else
338 msgfmt = "Both your branch and the tracked branch '%s' have own changes, you would eventually need to merge\n";
339
340 if (!prefixcmp(base, "refs/remotes/"))
341 base += strlen("refs/remotes/");
342 fprintf(stderr, msgfmt, base);
343
344 if (show_log) {
345 const char *args[32];
346 int ac;
347
348 ac = 0;
349 args[ac++] = "log";
350 args[ac++] = "--pretty=oneline";
351 args[ac++] = "--abbrev-commit";
352 args[ac++] = "--left-right";
353 args[ac++] = "--boundary";
354 args[ac++] = symmetric;
355 args[ac++] = "--";
356 args[ac] = NULL;
357
358 run_command_v_opt(args, RUN_GIT_CMD);
359 }
360 }
361
362
363 static void update_refs_for_switch(struct checkout_opts *opts,
364 struct branch_info *old,
365 struct branch_info *new)
366 {
367 struct strbuf msg;
368 const char *old_desc;
369 if (opts->new_branch) {
370 create_branch(old->name, opts->new_branch, new->name, 0,
371 opts->new_branch_log, opts->track);
372 new->name = opts->new_branch;
373 setup_branch_path(new);
374 }
375
376 strbuf_init(&msg, 0);
377 old_desc = old->name;
378 if (!old_desc)
379 old_desc = sha1_to_hex(old->commit->object.sha1);
380 strbuf_addf(&msg, "checkout: moving from %s to %s",
381 old_desc, new->name);
382
383 if (new->path) {
384 create_symref("HEAD", new->path, msg.buf);
385 if (!opts->quiet) {
386 if (old->path && !strcmp(new->path, old->path))
387 fprintf(stderr, "Already on \"%s\"\n",
388 new->name);
389 else
390 fprintf(stderr, "Switched to%s branch \"%s\"\n",
391 opts->new_branch ? " a new" : "",
392 new->name);
393 }
394 } else if (strcmp(new->name, "HEAD")) {
395 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
396 REF_NODEREF, DIE_ON_ERR);
397 if (!opts->quiet) {
398 if (old->path)
399 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);
400 describe_detached_head("HEAD is now at", new->commit);
401 }
402 }
403 remove_branch_state();
404 strbuf_release(&msg);
405 if (new->path || !strcmp(new->name, "HEAD"))
406 adjust_to_tracking(new, opts);
407 }
408
409 static int switch_branches(struct checkout_opts *opts,
410 struct branch_info *new, const char *prefix)
411 {
412 int ret = 0;
413 struct branch_info old;
414 unsigned char rev[20];
415 int flag;
416 memset(&old, 0, sizeof(old));
417 old.path = resolve_ref("HEAD", rev, 0, &flag);
418 old.commit = lookup_commit_reference_gently(rev, 1);
419 if (!(flag & REF_ISSYMREF))
420 old.path = NULL;
421
422 if (old.path && !prefixcmp(old.path, "refs/heads/"))
423 old.name = old.path + strlen("refs/heads/");
424
425 if (!new->name) {
426 new->name = "HEAD";
427 new->commit = old.commit;
428 if (!new->commit)
429 die("You are on a branch yet to be born");
430 parse_commit(new->commit);
431 }
432
433 /*
434 * If the new thing isn't a branch and isn't HEAD and we're
435 * not starting a new branch, and we want messages, and we
436 * weren't on a branch, and we're moving to a new commit,
437 * describe the old commit.
438 */
439 if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
440 !opts->quiet && !old.path && new->commit != old.commit)
441 describe_detached_head("Previous HEAD position was", old.commit);
442
443 if (!old.commit) {
444 if (!opts->quiet) {
445 fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
446 fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
447 }
448 opts->force = 1;
449 }
450
451 ret = merge_working_tree(opts, &old, new, prefix);
452 if (ret)
453 return ret;
454
455 update_refs_for_switch(opts, &old, new);
456
457 return post_checkout_hook(old.commit, new->commit, 1);
458 }
459
460 static int git_checkout_config(const char *var, const char *value)
461 {
462 return git_default_config(var, value);
463 }
464
465 int cmd_checkout(int argc, const char **argv, const char *prefix)
466 {
467 struct checkout_opts opts;
468 unsigned char rev[20];
469 const char *arg;
470 struct branch_info new;
471 struct tree *source_tree = NULL;
472 struct option options[] = {
473 OPT__QUIET(&opts.quiet),
474 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
475 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
476 OPT_SET_INT( 0 , "track", &opts.track, "track",
477 BRANCH_TRACK_EXPLICIT),
478 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
479 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
480 OPT_END(),
481 };
482
483 memset(&opts, 0, sizeof(opts));
484 memset(&new, 0, sizeof(new));
485
486 git_config(git_checkout_config);
487
488 opts.track = git_branch_track;
489
490 argc = parse_options(argc, argv, options, checkout_usage, 0);
491 if (argc) {
492 arg = argv[0];
493 if (get_sha1(arg, rev))
494 ;
495 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
496 new.name = arg;
497 setup_branch_path(&new);
498 if (resolve_ref(new.path, rev, 1, NULL))
499 new.commit = lookup_commit_reference(rev);
500 else
501 new.path = NULL;
502 parse_commit(new.commit);
503 source_tree = new.commit->tree;
504 argv++;
505 argc--;
506 } else if ((source_tree = parse_tree_indirect(rev))) {
507 argv++;
508 argc--;
509 }
510 }
511
512 if (argc && !strcmp(argv[0], "--")) {
513 argv++;
514 argc--;
515 }
516
517 if (!opts.new_branch && (opts.track != git_branch_track))
518 die("git checkout: --track and --no-track require -b");
519
520 if (opts.force && opts.merge)
521 die("git checkout: -f and -m are incompatible");
522
523 if (argc) {
524 const char **pathspec = get_pathspec(prefix, argv);
525 /* Checkout paths */
526 if (opts.new_branch || opts.force || opts.merge) {
527 if (argc == 1) {
528 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]);
529 } else {
530 die("git checkout: updating paths is incompatible with switching branches/forcing");
531 }
532 }
533
534 if (source_tree)
535 read_tree_some(source_tree, pathspec);
536 else
537 read_cache();
538 return checkout_paths(pathspec);
539 }
540
541 if (new.name && !new.commit) {
542 die("Cannot switch branch to a non-commit.");
543 }
544
545 return switch_branches(&opts, &new, prefix);
546 }