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 ? old->object.sha1 : null_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 skip_same_name(struct cache_entry *ce, int pos)
  80 {
  81         while (++pos < active_nr &&
  82                !strcmp(active_cache[pos]->name, ce->name))
  83                 ; /* skip */
  84         return pos;
  85 }
  86
  87
  88 static int checkout_paths(struct tree *source_tree, const char **pathspec)
  89 {
  90         int pos;
  91         struct checkout state;
  92         static char *ps_matched;
  93         unsigned char rev[20];
  94         int flag;
  95         struct commit *head;
  96         int errs = 0;
  97
  98         int newfd;
  99         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 100
 101         newfd = hold_locked_index(lock_file, 1);
 102         read_cache();
 103
 104         if (source_tree)
 105                 read_tree_some(source_tree, pathspec);
 106
 107         for (pos = 0; pathspec[pos]; pos++)
 108                 ;
 109         ps_matched = xcalloc(1, pos);
 110
 111         for (pos = 0; pos < active_nr; pos++) {
 112                 struct cache_entry *ce = active_cache[pos];
 113                 pathspec_match(pathspec, ps_matched, ce->name, 0);
 114         }
 115
 116         if (report_path_error(ps_matched, pathspec, 0))
 117                 return 1;
 118
 119         /* Any unmerged paths? */
 120         for (pos = 0; pos < active_nr; pos++) {
 121                 struct cache_entry *ce = active_cache[pos];
 122                 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
 123                         if (!ce_stage(ce))
 124                                 continue;
 125                         errs = 1;
 126                         error("path '%s' is unmerged", ce->name);
 127                         pos = skip_same_name(ce, pos) - 1;
 128                 }
 129         }
 130         if (errs)
 131                 return 1;
 132
 133         /* Now we are committed to check them out */
 134         memset(&state, 0, sizeof(state));
 135         state.force = 1;
 136         state.refresh_cache = 1;
 137         for (pos = 0; pos < active_nr; pos++) {
 138                 struct cache_entry *ce = active_cache[pos];
 139                 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
 140                         if (!ce_stage(ce)) {
 141                                 errs |= checkout_entry(ce, &state, NULL);
 142                                 continue;
 143                         }
 144                         pos = skip_same_name(ce, pos) - 1;
 145                 }
 146         }
 147
 148         if (write_cache(newfd, active_cache, active_nr) ||
 149             commit_locked_index(lock_file))
 150                 die("unable to write new index file");
 151
 152         resolve_ref("HEAD", rev, 0, &flag);
 153         head = lookup_commit_reference_gently(rev, 1);
 154
 155         errs |= post_checkout_hook(head, head, 0);
 156         return errs;
 157 }
 158
 159 static void show_local_changes(struct object *head)
 160 {
 161         struct rev_info rev;
 162         /* I think we want full paths, even if we're in a subdirectory. */
 163         init_revisions(&rev, NULL);
 164         rev.abbrev = 0;
 165         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 166         add_pending_object(&rev, head, NULL);
 167         run_diff_index(&rev, 0);
 168 }
 169
 170 static void describe_detached_head(char *msg, struct commit *commit)
 171 {
 172         struct strbuf sb;
 173         strbuf_init(&sb, 0);
 174         parse_commit(commit);
 175         pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
 176         fprintf(stderr, "%s %s... %s\n", msg,
 177                 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
 178         strbuf_release(&sb);
 179 }
 180
 181 struct checkout_opts {
 182         int quiet;
 183         int merge;
 184         int force;
 185         int writeout_error;
 186
 187         char *new_branch;
 188         int new_branch_log;
 189         enum branch_track track;
 190 };
 191
 192 static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
 193 {
 194         struct unpack_trees_options opts;
 195         struct tree_desc tree_desc;
 196
 197         memset(&opts, 0, sizeof(opts));
 198         opts.head_idx = -1;
 199         opts.update = worktree;
 200         opts.skip_unmerged = !worktree;
 201         opts.reset = 1;
 202         opts.merge = 1;
 203         opts.fn = oneway_merge;
 204         opts.verbose_update = !o->quiet;
 205         opts.src_index = &the_index;
 206         opts.dst_index = &the_index;
 207         parse_tree(tree);
 208         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 209         switch (unpack_trees(1, &tree_desc, &opts)) {
 210         case -2:
 211                 o->writeout_error = 1;
 212                 /*
 213                  * We return 0 nevertheless, as the index is all right
 214                  * and more importantly we have made best efforts to
 215                  * update paths in the work tree, and we cannot revert
 216                  * them.
 217                  */
 218         case 0:
 219                 return 0;
 220         default:
 221                 return 128;
 222         }
 223 }
 224
 225 struct branch_info {
 226         const char *name; /* The short name used */
 227         const char *path; /* The full name of a real branch */
 228         struct commit *commit; /* The named commit */
 229 };
 230
 231 static void setup_branch_path(struct branch_info *branch)
 232 {
 233         struct strbuf buf;
 234         strbuf_init(&buf, 0);
 235         strbuf_addstr(&buf, "refs/heads/");
 236         strbuf_addstr(&buf, branch->name);
 237         branch->path = strbuf_detach(&buf, NULL);
 238 }
 239
 240 static int merge_working_tree(struct checkout_opts *opts,
 241                               struct branch_info *old, struct branch_info *new)
 242 {
 243         int ret;
 244         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 245         int newfd = hold_locked_index(lock_file, 1);
 246         read_cache();
 247
 248         if (opts->force) {
 249                 ret = reset_tree(new->commit->tree, opts, 1);
 250                 if (ret)
 251                         return ret;
 252         } else {
 253                 struct tree_desc trees[2];
 254                 struct tree *tree;
 255                 struct unpack_trees_options topts;
 256
 257                 memset(&topts, 0, sizeof(topts));
 258                 topts.head_idx = -1;
 259                 topts.src_index = &the_index;
 260                 topts.dst_index = &the_index;
 261
 262                 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
 263
 264                 refresh_cache(REFRESH_QUIET);
 265
 266                 if (unmerged_cache()) {
 267                         error("you need to resolve your current index first");
 268                         return 1;
 269                 }
 270
 271                 /* 2-way merge to the new branch */
 272                 topts.initial_checkout = is_cache_unborn();
 273                 topts.update = 1;
 274                 topts.merge = 1;
 275                 topts.gently = opts->merge;
 276                 topts.verbose_update = !opts->quiet;
 277                 topts.fn = twoway_merge;
 278                 topts.dir = xcalloc(1, sizeof(*topts.dir));
 279                 topts.dir->show_ignored = 1;
 280                 topts.dir->exclude_per_dir = ".gitignore";
 281                 tree = parse_tree_indirect(old->commit->object.sha1);
 282                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 283                 tree = parse_tree_indirect(new->commit->object.sha1);
 284                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 285
 286                 ret = unpack_trees(2, trees, &topts);
 287                 if (ret == -1) {
 288                         /*
 289                          * Unpack couldn't do a trivial merge; either
 290                          * give up or do a real merge, depending on
 291                          * whether the merge flag was used.
 292                          */
 293                         struct tree *result;
 294                         struct tree *work;
 295                         if (!opts->merge)
 296                                 return 1;
 297                         parse_commit(old->commit);
 298
 299                         /* Do more real merge */
 300
 301                         /*
 302                          * We update the index fully, then write the
 303                          * tree from the index, then merge the new
 304                          * branch with the current tree, with the old
 305                          * branch as the base. Then we reset the index
 306                          * (but not the working tree) to the new
 307                          * branch, leaving the working tree as the
 308                          * merged version, but skipping unmerged
 309                          * entries in the index.
 310                          */
 311
 312                         add_files_to_cache(NULL, NULL, 0);
 313                         work = write_tree_from_memory();
 314
 315                         ret = reset_tree(new->commit->tree, opts, 1);
 316                         if (ret)
 317                                 return ret;
 318                         merge_trees(new->commit->tree, work, old->commit->tree,
 319                                     new->name, "local", &result);
 320                         ret = reset_tree(new->commit->tree, opts, 0);
 321                         if (ret)
 322                                 return ret;
 323                 }
 324         }
 325
 326         if (write_cache(newfd, active_cache, active_nr) ||
 327             commit_locked_index(lock_file))
 328                 die("unable to write new index file");
 329
 330         if (!opts->force && !opts->quiet)
 331                 show_local_changes(&new->commit->object);
 332
 333         return 0;
 334 }
 335
 336 static void report_tracking(struct branch_info *new)
 337 {
 338         struct strbuf sb = STRBUF_INIT;
 339         struct branch *branch = branch_get(new->name);
 340
 341         if (!format_tracking_info(branch, &sb))
 342                 return;
 343         fputs(sb.buf, stdout);
 344         strbuf_release(&sb);
 345 }
 346
 347 static void update_refs_for_switch(struct checkout_opts *opts,
 348                                    struct branch_info *old,
 349                                    struct branch_info *new)
 350 {
 351         struct strbuf msg;
 352         const char *old_desc;
 353         if (opts->new_branch) {
 354                 create_branch(old->name, opts->new_branch, new->name, 0,
 355                               opts->new_branch_log, opts->track);
 356                 new->name = opts->new_branch;
 357                 setup_branch_path(new);
 358         }
 359
 360         strbuf_init(&msg, 0);
 361         old_desc = old->name;
 362         if (!old_desc && old->commit)
 363                 old_desc = sha1_to_hex(old->commit->object.sha1);
 364         strbuf_addf(&msg, "checkout: moving from %s to %s",
 365                     old_desc ? old_desc : "(invalid)", new->name);
 366
 367         if (new->path) {
 368                 create_symref("HEAD", new->path, msg.buf);
 369                 if (!opts->quiet) {
 370                         if (old->path && !strcmp(new->path, old->path))
 371                                 fprintf(stderr, "Already on \"%s\"\n",
 372                                         new->name);
 373                         else
 374                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 375                                         opts->new_branch ? " a new" : "",
 376                                         new->name);
 377                 }
 378         } else if (strcmp(new->name, "HEAD")) {
 379                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 380                            REF_NODEREF, DIE_ON_ERR);
 381                 if (!opts->quiet) {
 382                         if (old->path)
 383                                 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);
 384                         describe_detached_head("HEAD is now at", new->commit);
 385                 }
 386         }
 387         remove_branch_state();
 388         strbuf_release(&msg);
 389         if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
 390                 report_tracking(new);
 391 }
 392
 393 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 394 {
 395         int ret = 0;
 396         struct branch_info old;
 397         unsigned char rev[20];
 398         int flag;
 399         memset(&old, 0, sizeof(old));
 400         old.path = resolve_ref("HEAD", rev, 0, &flag);
 401         old.commit = lookup_commit_reference_gently(rev, 1);
 402         if (!(flag & REF_ISSYMREF))
 403                 old.path = NULL;
 404
 405         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 406                 old.name = old.path + strlen("refs/heads/");
 407
 408         if (!new->name) {
 409                 new->name = "HEAD";
 410                 new->commit = old.commit;
 411                 if (!new->commit)
 412                         die("You are on a branch yet to be born");
 413                 parse_commit(new->commit);
 414         }
 415
 416         /*
 417          * If we were on a detached HEAD, but we are now moving to
 418          * a new commit, we want to mention the old commit once more
 419          * to remind the user that it might be lost.
 420          */
 421         if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
 422                 describe_detached_head("Previous HEAD position was", old.commit);
 423
 424         if (!old.commit && !opts->force) {
 425                 if (!opts->quiet) {
 426                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 427                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 428                 }
 429                 opts->force = 1;
 430         }
 431
 432         ret = merge_working_tree(opts, &old, new);
 433         if (ret)
 434                 return ret;
 435
 436         update_refs_for_switch(opts, &old, new);
 437
 438         ret = post_checkout_hook(old.commit, new->commit, 1);
 439         return ret || opts->writeout_error;
 440 }
 441
 442 int cmd_checkout(int argc, const char **argv, const char *prefix)
 443 {
 444         struct checkout_opts opts;
 445         unsigned char rev[20];
 446         const char *arg;
 447         struct branch_info new;
 448         struct tree *source_tree = NULL;
 449         struct option options[] = {
 450                 OPT__QUIET(&opts.quiet),
 451                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 452                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 453                 OPT_SET_INT('t', "track",  &opts.track, "track",
 454                         BRANCH_TRACK_EXPLICIT),
 455                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 456                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 457                 OPT_END(),
 458         };
 459         int has_dash_dash;
 460
 461         memset(&opts, 0, sizeof(opts));
 462         memset(&new, 0, sizeof(new));
 463
 464         git_config(git_default_config, NULL);
 465
 466         opts.track = git_branch_track;
 467
 468         argc = parse_options(argc, argv, options, checkout_usage,
 469                              PARSE_OPT_KEEP_DASHDASH);
 470
 471         if (!opts.new_branch && (opts.track != git_branch_track))
 472                 die("git checkout: --track and --no-track require -b");
 473
 474         if (opts.force && opts.merge)
 475                 die("git checkout: -f and -m are incompatible");
 476
 477         /*
 478          * case 1: git checkout <ref> -- [<paths>]
 479          *
 480          *   <ref> must be a valid tree, everything after the '--' must be
 481          *   a path.
 482          *
 483          * case 2: git checkout -- [<paths>]
 484          *
 485          *   everything after the '--' must be paths.
 486          *
 487          * case 3: git checkout <something> [<paths>]
 488          *
 489          *   With no paths, if <something> is a commit, that is to
 490          *   switch to the branch or detach HEAD at it.
 491          *
 492          *   Otherwise <something> shall not be ambiguous.
 493          *   - If it's *only* a reference, treat it like case (1).
 494          *   - If it's only a path, treat it like case (2).
 495          *   - else: fail.
 496          *
 497          */
 498         if (argc) {
 499                 if (!strcmp(argv[0], "--")) {       /* case (2) */
 500                         argv++;
 501                         argc--;
 502                         goto no_reference;
 503                 }
 504
 505                 arg = argv[0];
 506                 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
 507
 508                 if (get_sha1(arg, rev)) {
 509                         if (has_dash_dash)          /* case (1) */
 510                                 die("invalid reference: %s", arg);
 511                         goto no_reference;          /* case (3 -> 2) */
 512                 }
 513
 514                 /* we can't end up being in (2) anymore, eat the argument */
 515                 argv++;
 516                 argc--;
 517
 518                 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 519                         new.name = arg;
 520                         setup_branch_path(&new);
 521                         if (resolve_ref(new.path, rev, 1, NULL))
 522                                 new.commit = lookup_commit_reference(rev);
 523                         else
 524                                 new.path = NULL;
 525                         parse_commit(new.commit);
 526                         source_tree = new.commit->tree;
 527                 } else
 528                         source_tree = parse_tree_indirect(rev);
 529
 530                 if (!source_tree)                   /* case (1): want a tree */
 531                         die("reference is not a tree: %s", arg);
 532                 if (!has_dash_dash) {/* case (3 -> 1) */
 533                         /*
 534                          * Do not complain the most common case
 535                          *      git checkout branch
 536                          * even if there happen to be a file called 'branch';
 537                          * it would be extremely annoying.
 538                          */
 539                         if (argc)
 540                                 verify_non_filename(NULL, arg);
 541                 }
 542                 else {
 543                         argv++;
 544                         argc--;
 545                 }
 546         }
 547
 548 no_reference:
 549         if (argc) {
 550                 const char **pathspec = get_pathspec(prefix, argv);
 551
 552                 if (!pathspec)
 553                         die("invalid path specification");
 554
 555                 /* Checkout paths */
 556                 if (opts.new_branch || opts.force || opts.merge) {
 557                         if (argc == 1) {
 558                                 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]);
 559                         } else {
 560                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 561                         }
 562                 }
 563
 564                 return checkout_paths(source_tree, pathspec);
 565         }
 566
 567         if (opts.new_branch) {
 568                 struct strbuf buf;
 569                 strbuf_init(&buf, 0);
 570                 strbuf_addstr(&buf, "refs/heads/");
 571                 strbuf_addstr(&buf, opts.new_branch);
 572                 if (!get_sha1(buf.buf, rev))
 573                         die("git checkout: branch %s already exists", opts.new_branch);
 574                 if (check_ref_format(buf.buf))
 575                         die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);
 576                 strbuf_release(&buf);
 577         }
 578
 579         if (new.name && !new.commit) {
 580                 die("Cannot switch branch to a non-commit.");
 581         }
 582
 583         return switch_branches(&opts, &new);
 584 }