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