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, void *context)
  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, NULL);
  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         const 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                         struct merge_options o;
 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                         init_merge_options(&o);
 287                         o.verbosity = 0;
 288                         work = write_tree_from_memory(&o);
 289
 290                         ret = reset_tree(new->commit->tree, opts, 1);
 291                         if (ret)
 292                                 return ret;
 293                         o.branch1 = new->name;
 294                         o.branch2 = "local";
 295                         merge_trees(&o, new->commit->tree, work,
 296                                 old->commit->tree, &result);
 297                         ret = reset_tree(new->commit->tree, opts, 0);
 298                         if (ret)
 299                                 return ret;
 300                 }
 301         }
 302
 303         if (write_cache(newfd, active_cache, active_nr) ||
 304             commit_locked_index(lock_file))
 305                 die("unable to write new index file");
 306
 307         if (!opts->force)
 308                 show_local_changes(&new->commit->object);
 309
 310         return 0;
 311 }
 312
 313 static void report_tracking(struct branch_info *new)
 314 {
 315         struct strbuf sb = STRBUF_INIT;
 316         struct branch *branch = branch_get(new->name);
 317
 318         if (!format_tracking_info(branch, &sb))
 319                 return;
 320         fputs(sb.buf, stdout);
 321         strbuf_release(&sb);
 322 }
 323
 324 static void update_refs_for_switch(struct checkout_opts *opts,
 325                                    struct branch_info *old,
 326                                    struct branch_info *new)
 327 {
 328         struct strbuf msg;
 329         const char *old_desc;
 330         if (opts->new_branch) {
 331                 create_branch(old->name, opts->new_branch, new->name, 0,
 332                               opts->new_branch_log, opts->track);
 333                 new->name = opts->new_branch;
 334                 setup_branch_path(new);
 335         }
 336
 337         strbuf_init(&msg, 0);
 338         old_desc = old->name;
 339         if (!old_desc)
 340                 old_desc = sha1_to_hex(old->commit->object.sha1);
 341         strbuf_addf(&msg, "checkout: moving from %s to %s",
 342                     old_desc, new->name);
 343
 344         if (new->path) {
 345                 create_symref("HEAD", new->path, msg.buf);
 346                 if (!opts->quiet) {
 347                         if (old->path && !strcmp(new->path, old->path))
 348                                 fprintf(stderr, "Already on \"%s\"\n",
 349                                         new->name);
 350                         else
 351                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 352                                         opts->new_branch ? " a new" : "",
 353                                         new->name);
 354                 }
 355         } else if (strcmp(new->name, "HEAD")) {
 356                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 357                            REF_NODEREF, DIE_ON_ERR);
 358                 if (!opts->quiet) {
 359                         if (old->path)
 360                                 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);
 361                         describe_detached_head("HEAD is now at", new->commit);
 362                 }
 363         }
 364         remove_branch_state();
 365         strbuf_release(&msg);
 366         if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
 367                 report_tracking(new);
 368 }
 369
 370 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 371 {
 372         int ret = 0;
 373         struct branch_info old;
 374         unsigned char rev[20];
 375         int flag;
 376         memset(&old, 0, sizeof(old));
 377         old.path = resolve_ref("HEAD", rev, 0, &flag);
 378         old.commit = lookup_commit_reference_gently(rev, 1);
 379         if (!(flag & REF_ISSYMREF))
 380                 old.path = NULL;
 381
 382         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 383                 old.name = old.path + strlen("refs/heads/");
 384
 385         if (!new->name) {
 386                 new->name = "HEAD";
 387                 new->commit = old.commit;
 388                 if (!new->commit)
 389                         die("You are on a branch yet to be born");
 390                 parse_commit(new->commit);
 391         }
 392
 393         /*
 394          * If the new thing isn't a branch and isn't HEAD and we're
 395          * not starting a new branch, and we want messages, and we
 396          * weren't on a branch, and we're moving to a new commit,
 397          * describe the old commit.
 398          */
 399         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 400             !opts->quiet && !old.path && new->commit != old.commit)
 401                 describe_detached_head("Previous HEAD position was", old.commit);
 402
 403         if (!old.commit) {
 404                 if (!opts->quiet) {
 405                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 406                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 407                 }
 408                 opts->force = 1;
 409         }
 410
 411         ret = merge_working_tree(opts, &old, new);
 412         if (ret)
 413                 return ret;
 414
 415         update_refs_for_switch(opts, &old, new);
 416
 417         ret = post_checkout_hook(old.commit, new->commit, 1);
 418         return ret || opts->writeout_error;
 419 }
 420
 421 int cmd_checkout(int argc, const char **argv, const char *prefix)
 422 {
 423         struct checkout_opts opts;
 424         unsigned char rev[20];
 425         const char *arg;
 426         struct branch_info new;
 427         struct tree *source_tree = NULL;
 428         struct option options[] = {
 429                 OPT__QUIET(&opts.quiet),
 430                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 431                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 432                 OPT_SET_INT('t', "track",  &opts.track, "track",
 433                         BRANCH_TRACK_EXPLICIT),
 434                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 435                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 436                 OPT_END(),
 437         };
 438         int has_dash_dash;
 439
 440         memset(&opts, 0, sizeof(opts));
 441         memset(&new, 0, sizeof(new));
 442
 443         git_config(git_default_config, NULL);
 444
 445         opts.track = BRANCH_TRACK_UNSPECIFIED;
 446
 447         argc = parse_options(argc, argv, options, checkout_usage,
 448                              PARSE_OPT_KEEP_DASHDASH);
 449
 450         /* --track without -b should DWIM */
 451         if (0 < opts.track && !opts.new_branch) {
 452                 const char *argv0 = argv[0];
 453                 if (!argc || !strcmp(argv0, "--"))
 454                         die ("--track needs a branch name");
 455                 if (!prefixcmp(argv0, "refs/"))
 456                         argv0 += 5;
 457                 if (!prefixcmp(argv0, "remotes/"))
 458                         argv0 += 8;
 459                 argv0 = strchr(argv0, '/');
 460                 if (!argv0 || !argv0[1])
 461                         die ("Missing branch name; try -b");
 462                 opts.new_branch = argv0 + 1;
 463         }
 464
 465         if (opts.track == BRANCH_TRACK_UNSPECIFIED)
 466                 opts.track = git_branch_track;
 467
 468         if (opts.force && opts.merge)
 469                 die("git checkout: -f and -m are incompatible");
 470
 471         /*
 472          * case 1: git checkout <ref> -- [<paths>]
 473          *
 474          *   <ref> must be a valid tree, everything after the '--' must be
 475          *   a path.
 476          *
 477          * case 2: git checkout -- [<paths>]
 478          *
 479          *   everything after the '--' must be paths.
 480          *
 481          * case 3: git checkout <something> [<paths>]
 482          *
 483          *   With no paths, if <something> is a commit, that is to
 484          *   switch to the branch or detach HEAD at it.
 485          *
 486          *   Otherwise <something> shall not be ambiguous.
 487          *   - If it's *only* a reference, treat it like case (1).
 488          *   - If it's only a path, treat it like case (2).
 489          *   - else: fail.
 490          *
 491          */
 492         if (argc) {
 493                 if (!strcmp(argv[0], "--")) {       /* case (2) */
 494                         argv++;
 495                         argc--;
 496                         goto no_reference;
 497                 }
 498
 499                 arg = argv[0];
 500                 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
 501
 502                 if (get_sha1(arg, rev)) {
 503                         if (has_dash_dash)          /* case (1) */
 504                                 die("invalid reference: %s", arg);
 505                         goto no_reference;          /* case (3 -> 2) */
 506                 }
 507
 508                 /* we can't end up being in (2) anymore, eat the argument */
 509                 argv++;
 510                 argc--;
 511
 512                 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 513                         new.name = arg;
 514                         setup_branch_path(&new);
 515                         if (resolve_ref(new.path, rev, 1, NULL))
 516                                 new.commit = lookup_commit_reference(rev);
 517                         else
 518                                 new.path = NULL;
 519                         parse_commit(new.commit);
 520                         source_tree = new.commit->tree;
 521                 } else
 522                         source_tree = parse_tree_indirect(rev);
 523
 524                 if (!source_tree)                   /* case (1): want a tree */
 525                         die("reference is not a tree: %s", arg);
 526                 if (!has_dash_dash) {/* case (3 -> 1) */
 527                         /*
 528                          * Do not complain the most common case
 529                          *      git checkout branch
 530                          * even if there happen to be a file called 'branch';
 531                          * it would be extremely annoying.
 532                          */
 533                         if (argc)
 534                                 verify_non_filename(NULL, arg);
 535                 }
 536                 else {
 537                         argv++;
 538                         argc--;
 539                 }
 540         }
 541
 542 no_reference:
 543         if (argc) {
 544                 const char **pathspec = get_pathspec(prefix, argv);
 545
 546                 if (!pathspec)
 547                         die("invalid path specification");
 548
 549                 /* Checkout paths */
 550                 if (opts.new_branch || opts.force || opts.merge) {
 551                         if (argc == 1) {
 552                                 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]);
 553                         } else {
 554                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 555                         }
 556                 }
 557
 558                 return checkout_paths(source_tree, pathspec);
 559         }
 560
 561         if (new.name && !new.commit) {
 562                 die("Cannot switch branch to a non-commit.");
 563         }
 564
 565         return switch_branches(&opts, &new);
 566 }