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 }