Merge branch 'maint-1.5.5' into maint
[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 }