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 static int reset_to_new(struct tree *tree, int quiet)
 155 {
 156         struct unpack_trees_options opts;
 157         struct tree_desc tree_desc;
 158
 159         memset(&opts, 0, sizeof(opts));
 160         opts.head_idx = -1;
 161         opts.update = 1;
 162         opts.reset = 1;
 163         opts.merge = 1;
 164         opts.fn = oneway_merge;
 165         opts.verbose_update = !quiet;
 166         opts.src_index = &the_index;
 167         opts.dst_index = &the_index;
 168         parse_tree(tree);
 169         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 170         if (unpack_trees(1, &tree_desc, &opts))
 171                 return 128;
 172         return 0;
 173 }
 174
 175 static void reset_clean_to_new(struct tree *tree, int quiet)
 176 {
 177         struct unpack_trees_options opts;
 178         struct tree_desc tree_desc;
 179
 180         memset(&opts, 0, sizeof(opts));
 181         opts.head_idx = -1;
 182         opts.skip_unmerged = 1;
 183         opts.reset = 1;
 184         opts.merge = 1;
 185         opts.fn = oneway_merge;
 186         opts.verbose_update = !quiet;
 187         opts.src_index = &the_index;
 188         opts.dst_index = &the_index;
 189         parse_tree(tree);
 190         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 191         if (unpack_trees(1, &tree_desc, &opts))
 192                 exit(128);
 193 }
 194
 195 struct checkout_opts {
 196         int quiet;
 197         int merge;
 198         int force;
 199
 200         char *new_branch;
 201         int new_branch_log;
 202         enum branch_track track;
 203 };
 204
 205 struct branch_info {
 206         const char *name; /* The short name used */
 207         const char *path; /* The full name of a real branch */
 208         struct commit *commit; /* The named commit */
 209 };
 210
 211 static void setup_branch_path(struct branch_info *branch)
 212 {
 213         struct strbuf buf;
 214         strbuf_init(&buf, 0);
 215         strbuf_addstr(&buf, "refs/heads/");
 216         strbuf_addstr(&buf, branch->name);
 217         branch->path = strbuf_detach(&buf, NULL);
 218 }
 219
 220 static int merge_working_tree(struct checkout_opts *opts,
 221                               struct branch_info *old, struct branch_info *new)
 222 {
 223         int ret;
 224         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 225         int newfd = hold_locked_index(lock_file, 1);
 226         read_cache();
 227
 228         if (opts->force) {
 229                 ret = reset_to_new(new->commit->tree, opts->quiet);
 230                 if (ret)
 231                         return ret;
 232         } else {
 233                 struct tree_desc trees[2];
 234                 struct tree *tree;
 235                 struct unpack_trees_options topts;
 236
 237                 memset(&topts, 0, sizeof(topts));
 238                 topts.head_idx = -1;
 239                 topts.src_index = &the_index;
 240                 topts.dst_index = &the_index;
 241
 242                 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
 243
 244                 refresh_cache(REFRESH_QUIET);
 245
 246                 if (unmerged_cache()) {
 247                         error("you need to resolve your current index first");
 248                         return 1;
 249                 }
 250
 251                 /* 2-way merge to the new branch */
 252                 topts.update = 1;
 253                 topts.merge = 1;
 254                 topts.gently = opts->merge;
 255                 topts.verbose_update = !opts->quiet;
 256                 topts.fn = twoway_merge;
 257                 topts.dir = xcalloc(1, sizeof(*topts.dir));
 258                 topts.dir->show_ignored = 1;
 259                 topts.dir->exclude_per_dir = ".gitignore";
 260                 tree = parse_tree_indirect(old->commit->object.sha1);
 261                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 262                 tree = parse_tree_indirect(new->commit->object.sha1);
 263                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 264
 265                 if (unpack_trees(2, trees, &topts)) {
 266                         /*
 267                          * Unpack couldn't do a trivial merge; either
 268                          * give up or do a real merge, depending on
 269                          * whether the merge flag was used.
 270                          */
 271                         struct tree *result;
 272                         struct tree *work;
 273                         if (!opts->merge)
 274                                 return 1;
 275                         parse_commit(old->commit);
 276
 277                         /* Do more real merge */
 278
 279                         /*
 280                          * We update the index fully, then write the
 281                          * tree from the index, then merge the new
 282                          * branch with the current tree, with the old
 283                          * branch as the base. Then we reset the index
 284                          * (but not the working tree) to the new
 285                          * branch, leaving the working tree as the
 286                          * merged version, but skipping unmerged
 287                          * entries in the index.
 288                          */
 289
 290                         add_files_to_cache(NULL, NULL, 0);
 291                         work = write_tree_from_memory();
 292
 293                         ret = reset_to_new(new->commit->tree, opts->quiet);
 294                         if (ret)
 295                                 return ret;
 296                         merge_trees(new->commit->tree, work, old->commit->tree,
 297                                     new->name, "local", &result);
 298                         reset_clean_to_new(new->commit->tree, opts->quiet);
 299                 }
 300         }
 301
 302         if (write_cache(newfd, active_cache, active_nr) ||
 303             commit_locked_index(lock_file))
 304                 die("unable to write new index file");
 305
 306         if (!opts->force)
 307                 show_local_changes(&new->commit->object);
 308
 309         return 0;
 310 }
 311
 312 static void report_tracking(struct branch_info *new, struct checkout_opts *opts)
 313 {
 314         /*
 315          * We have switched to a new branch; is it building on
 316          * top of another branch, and if so does that other branch
 317          * have changes we do not have yet?
 318          */
 319         char *base;
 320         unsigned char sha1[20];
 321         struct commit *ours, *theirs;
 322         char symmetric[84];
 323         struct rev_info revs;
 324         const char *rev_argv[10];
 325         int rev_argc;
 326         int num_ours, num_theirs;
 327         const char *remote_msg;
 328         struct branch *branch = branch_get(new->name);
 329
 330         /*
 331          * Nothing to report unless we are marked to build on top of
 332          * somebody else.
 333          */
 334         if (!branch || !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
 335                 return;
 336
 337         /*
 338          * If what we used to build on no longer exists, there is
 339          * nothing to report.
 340          */
 341         base = branch->merge[0]->dst;
 342         if (!resolve_ref(base, sha1, 1, NULL))
 343                 return;
 344
 345         theirs = lookup_commit(sha1);
 346         ours = new->commit;
 347         if (!hashcmp(sha1, ours->object.sha1))
 348                 return; /* we are the same */
 349
 350         /* Run "rev-list --left-right ours...theirs" internally... */
 351         rev_argc = 0;
 352         rev_argv[rev_argc++] = NULL;
 353         rev_argv[rev_argc++] = "--left-right";
 354         rev_argv[rev_argc++] = symmetric;
 355         rev_argv[rev_argc++] = "--";
 356         rev_argv[rev_argc] = NULL;
 357
 358         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
 359         strcpy(symmetric + 40, "...");
 360         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
 361
 362         init_revisions(&revs, NULL);
 363         setup_revisions(rev_argc, rev_argv, &revs, NULL);
 364         prepare_revision_walk(&revs);
 365
 366         /* ... and count the commits on each side. */
 367         num_ours = 0;
 368         num_theirs = 0;
 369         while (1) {
 370                 struct commit *c = get_revision(&revs);
 371                 if (!c)
 372                         break;
 373                 if (c->object.flags & SYMMETRIC_LEFT)
 374                         num_ours++;
 375                 else
 376                         num_theirs++;
 377         }
 378
 379         if (!prefixcmp(base, "refs/remotes/")) {
 380                 remote_msg = " remote";
 381                 base += strlen("refs/remotes/");
 382         } else {
 383                 remote_msg = "";
 384         }
 385
 386         if (!num_theirs)
 387                 printf("Your branch is ahead of the tracked%s branch '%s' "
 388                        "by %d commit%s.\n",
 389                        remote_msg, base,
 390                        num_ours, (num_ours == 1) ? "" : "s");
 391         else if (!num_ours)
 392                 printf("Your branch is behind the tracked%s branch '%s' "
 393                        "by %d commit%s,\n"
 394                        "and can be fast-forwarded.\n",
 395                        remote_msg, base,
 396                        num_theirs, (num_theirs == 1) ? "" : "s");
 397         else
 398                 printf("Your branch and the tracked%s branch '%s' "
 399                        "have diverged,\nand respectively "
 400                        "have %d and %d different commit(s) each.\n",
 401                        remote_msg, base,
 402                        num_ours, num_theirs);
 403 }
 404
 405 static void update_refs_for_switch(struct checkout_opts *opts,
 406                                    struct branch_info *old,
 407                                    struct branch_info *new)
 408 {
 409         struct strbuf msg;
 410         const char *old_desc;
 411         if (opts->new_branch) {
 412                 create_branch(old->name, opts->new_branch, new->name, 0,
 413                               opts->new_branch_log, opts->track);
 414                 new->name = opts->new_branch;
 415                 setup_branch_path(new);
 416         }
 417
 418         strbuf_init(&msg, 0);
 419         old_desc = old->name;
 420         if (!old_desc)
 421                 old_desc = sha1_to_hex(old->commit->object.sha1);
 422         strbuf_addf(&msg, "checkout: moving from %s to %s",
 423                     old_desc, new->name);
 424
 425         if (new->path) {
 426                 create_symref("HEAD", new->path, msg.buf);
 427                 if (!opts->quiet) {
 428                         if (old->path && !strcmp(new->path, old->path))
 429                                 fprintf(stderr, "Already on \"%s\"\n",
 430                                         new->name);
 431                         else
 432                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 433                                         opts->new_branch ? " a new" : "",
 434                                         new->name);
 435                 }
 436         } else if (strcmp(new->name, "HEAD")) {
 437                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 438                            REF_NODEREF, DIE_ON_ERR);
 439                 if (!opts->quiet) {
 440                         if (old->path)
 441                                 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);
 442                         describe_detached_head("HEAD is now at", new->commit);
 443                 }
 444         }
 445         remove_branch_state();
 446         strbuf_release(&msg);
 447         if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
 448                 report_tracking(new, opts);
 449 }
 450
 451 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 452 {
 453         int ret = 0;
 454         struct branch_info old;
 455         unsigned char rev[20];
 456         int flag;
 457         memset(&old, 0, sizeof(old));
 458         old.path = resolve_ref("HEAD", rev, 0, &flag);
 459         old.commit = lookup_commit_reference_gently(rev, 1);
 460         if (!(flag & REF_ISSYMREF))
 461                 old.path = NULL;
 462
 463         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 464                 old.name = old.path + strlen("refs/heads/");
 465
 466         if (!new->name) {
 467                 new->name = "HEAD";
 468                 new->commit = old.commit;
 469                 if (!new->commit)
 470                         die("You are on a branch yet to be born");
 471                 parse_commit(new->commit);
 472         }
 473
 474         /*
 475          * If the new thing isn't a branch and isn't HEAD and we're
 476          * not starting a new branch, and we want messages, and we
 477          * weren't on a branch, and we're moving to a new commit,
 478          * describe the old commit.
 479          */
 480         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 481             !opts->quiet && !old.path && new->commit != old.commit)
 482                 describe_detached_head("Previous HEAD position was", old.commit);
 483
 484         if (!old.commit) {
 485                 if (!opts->quiet) {
 486                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 487                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 488                 }
 489                 opts->force = 1;
 490         }
 491
 492         ret = merge_working_tree(opts, &old, new);
 493         if (ret)
 494                 return ret;
 495
 496         update_refs_for_switch(opts, &old, new);
 497
 498         return post_checkout_hook(old.commit, new->commit, 1);
 499 }
 500
 501 int cmd_checkout(int argc, const char **argv, const char *prefix)
 502 {
 503         struct checkout_opts opts;
 504         unsigned char rev[20];
 505         const char *arg;
 506         struct branch_info new;
 507         struct tree *source_tree = NULL;
 508         struct option options[] = {
 509                 OPT__QUIET(&opts.quiet),
 510                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 511                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 512                 OPT_SET_INT('t', "track",  &opts.track, "track",
 513                         BRANCH_TRACK_EXPLICIT),
 514                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 515                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 516                 OPT_END(),
 517         };
 518
 519         memset(&opts, 0, sizeof(opts));
 520         memset(&new, 0, sizeof(new));
 521
 522         git_config(git_default_config, NULL);
 523
 524         opts.track = git_branch_track;
 525
 526         argc = parse_options(argc, argv, options, checkout_usage, 0);
 527         if (argc) {
 528                 arg = argv[0];
 529                 if (get_sha1(arg, rev))
 530                         ;
 531                 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 532                         new.name = arg;
 533                         setup_branch_path(&new);
 534                         if (resolve_ref(new.path, rev, 1, NULL))
 535                                 new.commit = lookup_commit_reference(rev);
 536                         else
 537                                 new.path = NULL;
 538                         parse_commit(new.commit);
 539                         source_tree = new.commit->tree;
 540                         argv++;
 541                         argc--;
 542                 } else if ((source_tree = parse_tree_indirect(rev))) {
 543                         argv++;
 544                         argc--;
 545                 }
 546         }
 547
 548         if (argc && !strcmp(argv[0], "--")) {
 549                 argv++;
 550                 argc--;
 551         }
 552
 553         if (!opts.new_branch && (opts.track != git_branch_track))
 554                 die("git checkout: --track and --no-track require -b");
 555
 556         if (opts.force && opts.merge)
 557                 die("git checkout: -f and -m are incompatible");
 558
 559         if (argc) {
 560                 const char **pathspec = get_pathspec(prefix, argv);
 561
 562                 if (!pathspec)
 563                         die("invalid path specification");
 564
 565                 /* Checkout paths */
 566                 if (opts.new_branch || opts.force || opts.merge) {
 567                         if (argc == 1) {
 568                                 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]);
 569                         } else {
 570                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 571                         }
 572                 }
 573
 574                 return checkout_paths(source_tree, pathspec);
 575         }
 576
 577         if (new.name && !new.commit) {
 578                 die("Cannot switch branch to a non-commit.");
 579         }
 580
 581         return switch_branches(&opts, &new);
 582 }