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