git.oblomov.eu Git - git/blob - builtin/checkout.c

   1 #include "builtin.h"
   2 #include "lockfile.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 "cache-tree.h"
   9 #include "unpack-trees.h"
  10 #include "dir.h"
  11 #include "run-command.h"
  12 #include "merge-recursive.h"
  13 #include "branch.h"
  14 #include "diff.h"
  15 #include "revision.h"
  16 #include "remote.h"
  17 #include "blob.h"
  18 #include "xdiff-interface.h"
  19 #include "ll-merge.h"
  20 #include "resolve-undo.h"
  21 #include "submodule-config.h"
  22 #include "submodule.h"
  23
  24 static const char * const checkout_usage[] = {
  25         N_("git checkout [<options>] <branch>"),
  26         N_("git checkout [<options>] [<branch>] -- <file>..."),
  27         NULL,
  28 };
  29
  30 struct checkout_opts {
  31         int patch_mode;
  32         int quiet;
  33         int merge;
  34         int force;
  35         int force_detach;
  36         int writeout_stage;
  37         int overwrite_ignore;
  38         int ignore_skipworktree;
  39         int ignore_other_worktrees;
  40         int show_progress;
  41
  42         const char *new_branch;
  43         const char *new_branch_force;
  44         const char *new_orphan_branch;
  45         int new_branch_log;
  46         enum branch_track track;
  47         struct diff_options diff_options;
  48
  49         int branch_exists;
  50         const char *prefix;
  51         struct pathspec pathspec;
  52         struct tree *source_tree;
  53 };
  54
  55 static int post_checkout_hook(struct commit *old, struct commit *new,
  56                               int changed)
  57 {
  58         return run_hook_le(NULL, "post-checkout",
  59                            oid_to_hex(old ? &old->object.oid : &null_oid),
  60                            oid_to_hex(new ? &new->object.oid : &null_oid),
  61                            changed ? "1" : "0", NULL);
  62         /* "new" can be NULL when checking out from the index before
  63            a commit exists. */
  64
  65 }
  66
  67 static int update_some(const unsigned char *sha1, struct strbuf *base,
  68                 const char *pathname, unsigned mode, int stage, void *context)
  69 {
  70         int len;
  71         struct cache_entry *ce;
  72         int pos;
  73
  74         if (S_ISDIR(mode))
  75                 return READ_TREE_RECURSIVE;
  76
  77         len = base->len + strlen(pathname);
  78         ce = xcalloc(1, cache_entry_size(len));
  79         hashcpy(ce->oid.hash, sha1);
  80         memcpy(ce->name, base->buf, base->len);
  81         memcpy(ce->name + base->len, pathname, len - base->len);
  82         ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
  83         ce->ce_namelen = len;
  84         ce->ce_mode = create_ce_mode(mode);
  85
  86         /*
  87          * If the entry is the same as the current index, we can leave the old
  88          * entry in place. Whether it is UPTODATE or not, checkout_entry will
  89          * do the right thing.
  90          */
  91         pos = cache_name_pos(ce->name, ce->ce_namelen);
  92         if (pos >= 0) {
  93                 struct cache_entry *old = active_cache[pos];
  94                 if (ce->ce_mode == old->ce_mode &&
  95                     !oidcmp(&ce->oid, &old->oid)) {
  96                         old->ce_flags |= CE_UPDATE;
  97                         free(ce);
  98                         return 0;
  99                 }
 100         }
 101
 102         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 103         return 0;
 104 }
 105
 106 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
 107 {
 108         read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
 109
 110         /* update the index with the given tree's info
 111          * for all args, expanding wildcards, and exit
 112          * with any non-zero return code.
 113          */
 114         return 0;
 115 }
 116
 117 static int skip_same_name(const struct cache_entry *ce, int pos)
 118 {
 119         while (++pos < active_nr &&
 120                !strcmp(active_cache[pos]->name, ce->name))
 121                 ; /* skip */
 122         return pos;
 123 }
 124
 125 static int check_stage(int stage, const struct cache_entry *ce, int pos)
 126 {
 127         while (pos < active_nr &&
 128                !strcmp(active_cache[pos]->name, ce->name)) {
 129                 if (ce_stage(active_cache[pos]) == stage)
 130                         return 0;
 131                 pos++;
 132         }
 133         if (stage == 2)
 134                 return error(_("path '%s' does not have our version"), ce->name);
 135         else
 136                 return error(_("path '%s' does not have their version"), ce->name);
 137 }
 138
 139 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 140 {
 141         unsigned seen = 0;
 142         const char *name = ce->name;
 143
 144         while (pos < active_nr) {
 145                 ce = active_cache[pos];
 146                 if (strcmp(name, ce->name))
 147                         break;
 148                 seen |= (1 << ce_stage(ce));
 149                 pos++;
 150         }
 151         if ((stages & seen) != stages)
 152                 return error(_("path '%s' does not have all necessary versions"),
 153                              name);
 154         return 0;
 155 }
 156
 157 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 158                           const struct checkout *state)
 159 {
 160         while (pos < active_nr &&
 161                !strcmp(active_cache[pos]->name, ce->name)) {
 162                 if (ce_stage(active_cache[pos]) == stage)
 163                         return checkout_entry(active_cache[pos], state, NULL);
 164                 pos++;
 165         }
 166         if (stage == 2)
 167                 return error(_("path '%s' does not have our version"), ce->name);
 168         else
 169                 return error(_("path '%s' does not have their version"), ce->name);
 170 }
 171
 172 static int checkout_merged(int pos, const struct checkout *state)
 173 {
 174         struct cache_entry *ce = active_cache[pos];
 175         const char *path = ce->name;
 176         mmfile_t ancestor, ours, theirs;
 177         int status;
 178         struct object_id oid;
 179         mmbuffer_t result_buf;
 180         struct object_id threeway[3];
 181         unsigned mode = 0;
 182
 183         memset(threeway, 0, sizeof(threeway));
 184         while (pos < active_nr) {
 185                 int stage;
 186                 stage = ce_stage(ce);
 187                 if (!stage || strcmp(path, ce->name))
 188                         break;
 189                 oidcpy(&threeway[stage - 1], &ce->oid);
 190                 if (stage == 2)
 191                         mode = create_ce_mode(ce->ce_mode);
 192                 pos++;
 193                 ce = active_cache[pos];
 194         }
 195         if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 196                 return error(_("path '%s' does not have necessary versions"), path);
 197
 198         read_mmblob(&ancestor, &threeway[0]);
 199         read_mmblob(&ours, &threeway[1]);
 200         read_mmblob(&theirs, &threeway[2]);
 201
 202         /*
 203          * NEEDSWORK: re-create conflicts from merges with
 204          * merge.renormalize set, too
 205          */
 206         status = ll_merge(&result_buf, path, &ancestor, "base",
 207                           &ours, "ours", &theirs, "theirs", NULL);
 208         free(ancestor.ptr);
 209         free(ours.ptr);
 210         free(theirs.ptr);
 211         if (status < 0 || !result_buf.ptr) {
 212                 free(result_buf.ptr);
 213                 return error(_("path '%s': cannot merge"), path);
 214         }
 215
 216         /*
 217          * NEEDSWORK:
 218          * There is absolutely no reason to write this as a blob object
 219          * and create a phony cache entry.  This hack is primarily to get
 220          * to the write_entry() machinery that massages the contents to
 221          * work-tree format and writes out which only allows it for a
 222          * cache entry.  The code in write_entry() needs to be refactored
 223          * to allow us to feed a <buffer, size, mode> instead of a cache
 224          * entry.  Such a refactoring would help merge_recursive as well
 225          * (it also writes the merge result to the object database even
 226          * when it may contain conflicts).
 227          */
 228         if (write_sha1_file(result_buf.ptr, result_buf.size,
 229                             blob_type, oid.hash))
 230                 die(_("Unable to add merge result for '%s'"), path);
 231         free(result_buf.ptr);
 232         ce = make_cache_entry(mode, oid.hash, path, 2, 0);
 233         if (!ce)
 234                 die(_("make_cache_entry failed for path '%s'"), path);
 235         status = checkout_entry(ce, state, NULL);
 236         free(ce);
 237         return status;
 238 }
 239
 240 static int checkout_paths(const struct checkout_opts *opts,
 241                           const char *revision)
 242 {
 243         int pos;
 244         struct checkout state = CHECKOUT_INIT;
 245         static char *ps_matched;
 246         struct object_id rev;
 247         struct commit *head;
 248         int errs = 0;
 249         struct lock_file *lock_file;
 250
 251         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 252                 die(_("'%s' cannot be used with updating paths"), "--track");
 253
 254         if (opts->new_branch_log)
 255                 die(_("'%s' cannot be used with updating paths"), "-l");
 256
 257         if (opts->force && opts->patch_mode)
 258                 die(_("'%s' cannot be used with updating paths"), "-f");
 259
 260         if (opts->force_detach)
 261                 die(_("'%s' cannot be used with updating paths"), "--detach");
 262
 263         if (opts->merge && opts->patch_mode)
 264                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 265
 266         if (opts->force && opts->merge)
 267                 die(_("'%s' cannot be used with %s"), "-f", "-m");
 268
 269         if (opts->new_branch)
 270                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 271                     opts->new_branch);
 272
 273         if (opts->patch_mode)
 274                 return run_add_interactive(revision, "--patch=checkout",
 275                                            &opts->pathspec);
 276
 277         lock_file = xcalloc(1, sizeof(struct lock_file));
 278
 279         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 280         if (read_cache_preload(&opts->pathspec) < 0)
 281                 return error(_("index file corrupt"));
 282
 283         if (opts->source_tree)
 284                 read_tree_some(opts->source_tree, &opts->pathspec);
 285
 286         ps_matched = xcalloc(opts->pathspec.nr, 1);
 287
 288         /*
 289          * Make sure all pathspecs participated in locating the paths
 290          * to be checked out.
 291          */
 292         for (pos = 0; pos < active_nr; pos++) {
 293                 struct cache_entry *ce = active_cache[pos];
 294                 ce->ce_flags &= ~CE_MATCHED;
 295                 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 296                         continue;
 297                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 298                         /*
 299                          * "git checkout tree-ish -- path", but this entry
 300                          * is in the original index; it will not be checked
 301                          * out to the working tree and it does not matter
 302                          * if pathspec matched this entry.  We will not do
 303                          * anything to this entry at all.
 304                          */
 305                         continue;
 306                 /*
 307                  * Either this entry came from the tree-ish we are
 308                  * checking the paths out of, or we are checking out
 309                  * of the index.
 310                  *
 311                  * If it comes from the tree-ish, we already know it
 312                  * matches the pathspec and could just stamp
 313                  * CE_MATCHED to it from update_some(). But we still
 314                  * need ps_matched and read_tree_recursive (and
 315                  * eventually tree_entry_interesting) cannot fill
 316                  * ps_matched yet. Once it can, we can avoid calling
 317                  * match_pathspec() for _all_ entries when
 318                  * opts->source_tree != NULL.
 319                  */
 320                 if (ce_path_match(ce, &opts->pathspec, ps_matched))
 321                         ce->ce_flags |= CE_MATCHED;
 322         }
 323
 324         if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
 325                 free(ps_matched);
 326                 return 1;
 327         }
 328         free(ps_matched);
 329
 330         /* "checkout -m path" to recreate conflicted state */
 331         if (opts->merge)
 332                 unmerge_marked_index(&the_index);
 333
 334         /* Any unmerged paths? */
 335         for (pos = 0; pos < active_nr; pos++) {
 336                 const struct cache_entry *ce = active_cache[pos];
 337                 if (ce->ce_flags & CE_MATCHED) {
 338                         if (!ce_stage(ce))
 339                                 continue;
 340                         if (opts->force) {
 341                                 warning(_("path '%s' is unmerged"), ce->name);
 342                         } else if (opts->writeout_stage) {
 343                                 errs |= check_stage(opts->writeout_stage, ce, pos);
 344                         } else if (opts->merge) {
 345                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 346                         } else {
 347                                 errs = 1;
 348                                 error(_("path '%s' is unmerged"), ce->name);
 349                         }
 350                         pos = skip_same_name(ce, pos) - 1;
 351                 }
 352         }
 353         if (errs)
 354                 return 1;
 355
 356         /* Now we are committed to check them out */
 357         state.force = 1;
 358         state.refresh_cache = 1;
 359         state.istate = &the_index;
 360         for (pos = 0; pos < active_nr; pos++) {
 361                 struct cache_entry *ce = active_cache[pos];
 362                 if (ce->ce_flags & CE_MATCHED) {
 363                         if (!ce_stage(ce)) {
 364                                 errs |= checkout_entry(ce, &state, NULL);
 365                                 continue;
 366                         }
 367                         if (opts->writeout_stage)
 368                                 errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
 369                         else if (opts->merge)
 370                                 errs |= checkout_merged(pos, &state);
 371                         pos = skip_same_name(ce, pos) - 1;
 372                 }
 373         }
 374
 375         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 376                 die(_("unable to write new index file"));
 377
 378         read_ref_full("HEAD", 0, rev.hash, NULL);
 379         head = lookup_commit_reference_gently(&rev, 1);
 380
 381         errs |= post_checkout_hook(head, head, 0);
 382         return errs;
 383 }
 384
 385 static void show_local_changes(struct object *head,
 386                                const struct diff_options *opts)
 387 {
 388         struct rev_info rev;
 389         /* I think we want full paths, even if we're in a subdirectory. */
 390         init_revisions(&rev, NULL);
 391         rev.diffopt.flags = opts->flags;
 392         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 393         diff_setup_done(&rev.diffopt);
 394         add_pending_object(&rev, head, NULL);
 395         run_diff_index(&rev, 0);
 396 }
 397
 398 static void describe_detached_head(const char *msg, struct commit *commit)
 399 {
 400         struct strbuf sb = STRBUF_INIT;
 401         if (!parse_commit(commit))
 402                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 403         fprintf(stderr, "%s %s... %s\n", msg,
 404                 find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
 405         strbuf_release(&sb);
 406 }
 407
 408 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 409                       int worktree, int *writeout_error)
 410 {
 411         struct unpack_trees_options opts;
 412         struct tree_desc tree_desc;
 413
 414         memset(&opts, 0, sizeof(opts));
 415         opts.head_idx = -1;
 416         opts.update = worktree;
 417         opts.skip_unmerged = !worktree;
 418         opts.reset = 1;
 419         opts.merge = 1;
 420         opts.fn = oneway_merge;
 421         opts.verbose_update = o->show_progress;
 422         opts.src_index = &the_index;
 423         opts.dst_index = &the_index;
 424         parse_tree(tree);
 425         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 426         switch (unpack_trees(1, &tree_desc, &opts)) {
 427         case -2:
 428                 *writeout_error = 1;
 429                 /*
 430                  * We return 0 nevertheless, as the index is all right
 431                  * and more importantly we have made best efforts to
 432                  * update paths in the work tree, and we cannot revert
 433                  * them.
 434                  */
 435         case 0:
 436                 return 0;
 437         default:
 438                 return 128;
 439         }
 440 }
 441
 442 struct branch_info {
 443         const char *name; /* The short name used */
 444         const char *path; /* The full name of a real branch */
 445         struct commit *commit; /* The named commit */
 446         /*
 447          * if not null the branch is detached because it's already
 448          * checked out in this checkout
 449          */
 450         char *checkout;
 451 };
 452
 453 static void setup_branch_path(struct branch_info *branch)
 454 {
 455         struct strbuf buf = STRBUF_INIT;
 456
 457         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 458         if (strcmp(buf.buf, branch->name))
 459                 branch->name = xstrdup(buf.buf);
 460         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 461         branch->path = strbuf_detach(&buf, NULL);
 462 }
 463
 464 static int merge_working_tree(const struct checkout_opts *opts,
 465                               struct branch_info *old,
 466                               struct branch_info *new,
 467                               int *writeout_error)
 468 {
 469         int ret;
 470         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 471
 472         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 473         if (read_cache_preload(NULL) < 0)
 474                 return error(_("index file corrupt"));
 475
 476         resolve_undo_clear();
 477         if (opts->force) {
 478                 ret = reset_tree(new->commit->tree, opts, 1, writeout_error);
 479                 if (ret)
 480                         return ret;
 481         } else {
 482                 struct tree_desc trees[2];
 483                 struct tree *tree;
 484                 struct unpack_trees_options topts;
 485
 486                 memset(&topts, 0, sizeof(topts));
 487                 topts.head_idx = -1;
 488                 topts.src_index = &the_index;
 489                 topts.dst_index = &the_index;
 490
 491                 setup_unpack_trees_porcelain(&topts, "checkout");
 492
 493                 refresh_cache(REFRESH_QUIET);
 494
 495                 if (unmerged_cache()) {
 496                         error(_("you need to resolve your current index first"));
 497                         return 1;
 498                 }
 499
 500                 /* 2-way merge to the new branch */
 501                 topts.initial_checkout = is_cache_unborn();
 502                 topts.update = 1;
 503                 topts.merge = 1;
 504                 topts.gently = opts->merge && old->commit;
 505                 topts.verbose_update = opts->show_progress;
 506                 topts.fn = twoway_merge;
 507                 if (opts->overwrite_ignore) {
 508                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 509                         topts.dir->flags |= DIR_SHOW_IGNORED;
 510                         setup_standard_excludes(topts.dir);
 511                 }
 512                 tree = parse_tree_indirect(old->commit ?
 513                                            &old->commit->object.oid :
 514                                            &empty_tree_oid);
 515                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 516                 tree = parse_tree_indirect(&new->commit->object.oid);
 517                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 518
 519                 ret = unpack_trees(2, trees, &topts);
 520                 if (ret == -1) {
 521                         /*
 522                          * Unpack couldn't do a trivial merge; either
 523                          * give up or do a real merge, depending on
 524                          * whether the merge flag was used.
 525                          */
 526                         struct tree *result;
 527                         struct tree *work;
 528                         struct merge_options o;
 529                         if (!opts->merge)
 530                                 return 1;
 531
 532                         /*
 533                          * Without old->commit, the below is the same as
 534                          * the two-tree unpack we already tried and failed.
 535                          */
 536                         if (!old->commit)
 537                                 return 1;
 538
 539                         /* Do more real merge */
 540
 541                         /*
 542                          * We update the index fully, then write the
 543                          * tree from the index, then merge the new
 544                          * branch with the current tree, with the old
 545                          * branch as the base. Then we reset the index
 546                          * (but not the working tree) to the new
 547                          * branch, leaving the working tree as the
 548                          * merged version, but skipping unmerged
 549                          * entries in the index.
 550                          */
 551
 552                         add_files_to_cache(NULL, NULL, 0);
 553                         /*
 554                          * NEEDSWORK: carrying over local changes
 555                          * when branches have different end-of-line
 556                          * normalization (or clean+smudge rules) is
 557                          * a pain; plumb in an option to set
 558                          * o.renormalize?
 559                          */
 560                         init_merge_options(&o);
 561                         o.verbosity = 0;
 562                         work = write_tree_from_memory(&o);
 563
 564                         ret = reset_tree(new->commit->tree, opts, 1,
 565                                          writeout_error);
 566                         if (ret)
 567                                 return ret;
 568                         o.ancestor = old->name;
 569                         o.branch1 = new->name;
 570                         o.branch2 = "local";
 571                         ret = merge_trees(&o, new->commit->tree, work,
 572                                 old->commit->tree, &result);
 573                         if (ret < 0)
 574                                 exit(128);
 575                         ret = reset_tree(new->commit->tree, opts, 0,
 576                                          writeout_error);
 577                         strbuf_release(&o.obuf);
 578                         if (ret)
 579                                 return ret;
 580                 }
 581         }
 582
 583         if (!active_cache_tree)
 584                 active_cache_tree = cache_tree();
 585
 586         if (!cache_tree_fully_valid(active_cache_tree))
 587                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 588
 589         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 590                 die(_("unable to write new index file"));
 591
 592         if (!opts->force && !opts->quiet)
 593                 show_local_changes(&new->commit->object, &opts->diff_options);
 594
 595         return 0;
 596 }
 597
 598 static void report_tracking(struct branch_info *new)
 599 {
 600         struct strbuf sb = STRBUF_INIT;
 601         struct branch *branch = branch_get(new->name);
 602
 603         if (!format_tracking_info(branch, &sb))
 604                 return;
 605         fputs(sb.buf, stdout);
 606         strbuf_release(&sb);
 607 }
 608
 609 static void update_refs_for_switch(const struct checkout_opts *opts,
 610                                    struct branch_info *old,
 611                                    struct branch_info *new)
 612 {
 613         struct strbuf msg = STRBUF_INIT;
 614         const char *old_desc, *reflog_msg;
 615         if (opts->new_branch) {
 616                 if (opts->new_orphan_branch) {
 617                         char *refname;
 618
 619                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 620                         if (opts->new_branch_log &&
 621                             !should_autocreate_reflog(refname)) {
 622                                 int ret;
 623                                 struct strbuf err = STRBUF_INIT;
 624
 625                                 ret = safe_create_reflog(refname, 1, &err);
 626                                 if (ret) {
 627                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 628                                                 opts->new_orphan_branch, err.buf);
 629                                         strbuf_release(&err);
 630                                         free(refname);
 631                                         return;
 632                                 }
 633                                 strbuf_release(&err);
 634                         }
 635                         free(refname);
 636                 }
 637                 else
 638                         create_branch(opts->new_branch, new->name,
 639                                       opts->new_branch_force ? 1 : 0,
 640                                       opts->new_branch_log,
 641                                       opts->new_branch_force ? 1 : 0,
 642                                       opts->quiet,
 643                                       opts->track);
 644                 new->name = opts->new_branch;
 645                 setup_branch_path(new);
 646         }
 647
 648         old_desc = old->name;
 649         if (!old_desc && old->commit)
 650                 old_desc = oid_to_hex(&old->commit->object.oid);
 651
 652         reflog_msg = getenv("GIT_REFLOG_ACTION");
 653         if (!reflog_msg)
 654                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 655                         old_desc ? old_desc : "(invalid)", new->name);
 656         else
 657                 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
 658
 659         if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
 660                 /* Nothing to do. */
 661         } else if (opts->force_detach || !new->path) {  /* No longer on any branch. */
 662                 update_ref(msg.buf, "HEAD", new->commit->object.oid.hash, NULL,
 663                            REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
 664                 if (!opts->quiet) {
 665                         if (old->path &&
 666                             advice_detached_head && !opts->force_detach)
 667                                 detach_advice(new->name);
 668                         describe_detached_head(_("HEAD is now at"), new->commit);
 669                 }
 670         } else if (new->path) { /* Switch branches. */
 671                 if (create_symref("HEAD", new->path, msg.buf) < 0)
 672                         die(_("unable to update HEAD"));
 673                 if (!opts->quiet) {
 674                         if (old->path && !strcmp(new->path, old->path)) {
 675                                 if (opts->new_branch_force)
 676                                         fprintf(stderr, _("Reset branch '%s'\n"),
 677                                                 new->name);
 678                                 else
 679                                         fprintf(stderr, _("Already on '%s'\n"),
 680                                                 new->name);
 681                         } else if (opts->new_branch) {
 682                                 if (opts->branch_exists)
 683                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new->name);
 684                                 else
 685                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new->name);
 686                         } else {
 687                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 688                                         new->name);
 689                         }
 690                 }
 691                 if (old->path && old->name) {
 692                         if (!ref_exists(old->path) && reflog_exists(old->path))
 693                                 delete_reflog(old->path);
 694                 }
 695         }
 696         remove_branch_state();
 697         strbuf_release(&msg);
 698         if (!opts->quiet &&
 699             (new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
 700                 report_tracking(new);
 701 }
 702
 703 static int add_pending_uninteresting_ref(const char *refname,
 704                                          const struct object_id *oid,
 705                                          int flags, void *cb_data)
 706 {
 707         add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 708         return 0;
 709 }
 710
 711 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 712 {
 713         strbuf_addstr(sb, "  ");
 714         strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
 715         strbuf_addch(sb, ' ');
 716         if (!parse_commit(commit))
 717                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 718         strbuf_addch(sb, '\n');
 719 }
 720
 721 #define ORPHAN_CUTOFF 4
 722 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 723 {
 724         struct commit *c, *last = NULL;
 725         struct strbuf sb = STRBUF_INIT;
 726         int lost = 0;
 727         while ((c = get_revision(revs)) != NULL) {
 728                 if (lost < ORPHAN_CUTOFF)
 729                         describe_one_orphan(&sb, c);
 730                 last = c;
 731                 lost++;
 732         }
 733         if (ORPHAN_CUTOFF < lost) {
 734                 int more = lost - ORPHAN_CUTOFF;
 735                 if (more == 1)
 736                         describe_one_orphan(&sb, last);
 737                 else
 738                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 739         }
 740
 741         fprintf(stderr,
 742                 Q_(
 743                 /* The singular version */
 744                 "Warning: you are leaving %d commit behind, "
 745                 "not connected to\n"
 746                 "any of your branches:\n\n"
 747                 "%s\n",
 748                 /* The plural version */
 749                 "Warning: you are leaving %d commits behind, "
 750                 "not connected to\n"
 751                 "any of your branches:\n\n"
 752                 "%s\n",
 753                 /* Give ngettext() the count */
 754                 lost),
 755                 lost,
 756                 sb.buf);
 757         strbuf_release(&sb);
 758
 759         if (advice_detached_head)
 760                 fprintf(stderr,
 761                         Q_(
 762                         /* The singular version */
 763                         "If you want to keep it by creating a new branch, "
 764                         "this may be a good time\nto do so with:\n\n"
 765                         " git branch <new-branch-name> %s\n\n",
 766                         /* The plural version */
 767                         "If you want to keep them by creating a new branch, "
 768                         "this may be a good time\nto do so with:\n\n"
 769                         " git branch <new-branch-name> %s\n\n",
 770                         /* Give ngettext() the count */
 771                         lost),
 772                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
 773 }
 774
 775 /*
 776  * We are about to leave commit that was at the tip of a detached
 777  * HEAD.  If it is not reachable from any ref, this is the last chance
 778  * for the user to do so without resorting to reflog.
 779  */
 780 static void orphaned_commit_warning(struct commit *old, struct commit *new)
 781 {
 782         struct rev_info revs;
 783         struct object *object = &old->object;
 784         struct object_array refs;
 785
 786         init_revisions(&revs, NULL);
 787         setup_revisions(0, NULL, &revs, NULL);
 788
 789         object->flags &= ~UNINTERESTING;
 790         add_pending_object(&revs, object, oid_to_hex(&object->oid));
 791
 792         for_each_ref(add_pending_uninteresting_ref, &revs);
 793         add_pending_oid(&revs, "HEAD", &new->object.oid, UNINTERESTING);
 794
 795         refs = revs.pending;
 796         revs.leak_pending = 1;
 797
 798         if (prepare_revision_walk(&revs))
 799                 die(_("internal error in revision walk"));
 800         if (!(old->object.flags & UNINTERESTING))
 801                 suggest_reattach(old, &revs);
 802         else
 803                 describe_detached_head(_("Previous HEAD position was"), old);
 804
 805         clear_commit_marks_for_object_array(&refs, ALL_REV_FLAGS);
 806         free(refs.objects);
 807 }
 808
 809 static int switch_branches(const struct checkout_opts *opts,
 810                            struct branch_info *new)
 811 {
 812         int ret = 0;
 813         struct branch_info old;
 814         void *path_to_free;
 815         struct object_id rev;
 816         int flag, writeout_error = 0;
 817         memset(&old, 0, sizeof(old));
 818         old.path = path_to_free = resolve_refdup("HEAD", 0, rev.hash, &flag);
 819         if (old.path)
 820                 old.commit = lookup_commit_reference_gently(&rev, 1);
 821         if (!(flag & REF_ISSYMREF))
 822                 old.path = NULL;
 823
 824         if (old.path)
 825                 skip_prefix(old.path, "refs/heads/", &old.name);
 826
 827         if (!new->name) {
 828                 new->name = "HEAD";
 829                 new->commit = old.commit;
 830                 if (!new->commit)
 831                         die(_("You are on a branch yet to be born"));
 832                 parse_commit_or_die(new->commit);
 833         }
 834
 835         ret = merge_working_tree(opts, &old, new, &writeout_error);
 836         if (ret) {
 837                 free(path_to_free);
 838                 return ret;
 839         }
 840
 841         if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
 842                 orphaned_commit_warning(old.commit, new->commit);
 843
 844         update_refs_for_switch(opts, &old, new);
 845
 846         ret = post_checkout_hook(old.commit, new->commit, 1);
 847         free(path_to_free);
 848         return ret || writeout_error;
 849 }
 850
 851 static int git_checkout_config(const char *var, const char *value, void *cb)
 852 {
 853         if (!strcmp(var, "diff.ignoresubmodules")) {
 854                 struct checkout_opts *opts = cb;
 855                 handle_ignore_submodules_arg(&opts->diff_options, value);
 856                 return 0;
 857         }
 858
 859         if (starts_with(var, "submodule."))
 860                 return submodule_config(var, value, NULL);
 861
 862         return git_xmerge_config(var, value, NULL);
 863 }
 864
 865 struct tracking_name_data {
 866         /* const */ char *src_ref;
 867         char *dst_ref;
 868         struct object_id *dst_oid;
 869         int unique;
 870 };
 871
 872 static int check_tracking_name(struct remote *remote, void *cb_data)
 873 {
 874         struct tracking_name_data *cb = cb_data;
 875         struct refspec query;
 876         memset(&query, 0, sizeof(struct refspec));
 877         query.src = cb->src_ref;
 878         if (remote_find_tracking(remote, &query) ||
 879             get_oid(query.dst, cb->dst_oid)) {
 880                 free(query.dst);
 881                 return 0;
 882         }
 883         if (cb->dst_ref) {
 884                 free(query.dst);
 885                 cb->unique = 0;
 886                 return 0;
 887         }
 888         cb->dst_ref = query.dst;
 889         return 0;
 890 }
 891
 892 static const char *unique_tracking_name(const char *name, struct object_id *oid)
 893 {
 894         struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
 895         cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 896         cb_data.dst_oid = oid;
 897         for_each_remote(check_tracking_name, &cb_data);
 898         free(cb_data.src_ref);
 899         if (cb_data.unique)
 900                 return cb_data.dst_ref;
 901         free(cb_data.dst_ref);
 902         return NULL;
 903 }
 904
 905 static int parse_branchname_arg(int argc, const char **argv,
 906                                 int dwim_new_local_branch_ok,
 907                                 struct branch_info *new,
 908                                 struct checkout_opts *opts,
 909                                 struct object_id *rev)
 910 {
 911         struct tree **source_tree = &opts->source_tree;
 912         const char **new_branch = &opts->new_branch;
 913         int argcount = 0;
 914         struct object_id branch_rev;
 915         const char *arg;
 916         int dash_dash_pos;
 917         int has_dash_dash = 0;
 918         int i;
 919
 920         /*
 921          * case 1: git checkout <ref> -- [<paths>]
 922          *
 923          *   <ref> must be a valid tree, everything after the '--' must be
 924          *   a path.
 925          *
 926          * case 2: git checkout -- [<paths>]
 927          *
 928          *   everything after the '--' must be paths.
 929          *
 930          * case 3: git checkout <something> [--]
 931          *
 932          *   (a) If <something> is a commit, that is to
 933          *       switch to the branch or detach HEAD at it.  As a special case,
 934          *       if <something> is A...B (missing A or B means HEAD but you can
 935          *       omit at most one side), and if there is a unique merge base
 936          *       between A and B, A...B names that merge base.
 937          *
 938          *   (b) If <something> is _not_ a commit, either "--" is present
 939          *       or <something> is not a path, no -t or -b was given, and
 940          *       and there is a tracking branch whose name is <something>
 941          *       in one and only one remote, then this is a short-hand to
 942          *       fork local <something> from that remote-tracking branch.
 943          *
 944          *   (c) Otherwise, if "--" is present, treat it like case (1).
 945          *
 946          *   (d) Otherwise :
 947          *       - if it's a reference, treat it like case (1)
 948          *       - else if it's a path, treat it like case (2)
 949          *       - else: fail.
 950          *
 951          * case 4: git checkout <something> <paths>
 952          *
 953          *   The first argument must not be ambiguous.
 954          *   - If it's *only* a reference, treat it like case (1).
 955          *   - If it's only a path, treat it like case (2).
 956          *   - else: fail.
 957          *
 958          */
 959         if (!argc)
 960                 return 0;
 961
 962         arg = argv[0];
 963         dash_dash_pos = -1;
 964         for (i = 0; i < argc; i++) {
 965                 if (!strcmp(argv[i], "--")) {
 966                         dash_dash_pos = i;
 967                         break;
 968                 }
 969         }
 970         if (dash_dash_pos == 0)
 971                 return 1; /* case (2) */
 972         else if (dash_dash_pos == 1)
 973                 has_dash_dash = 1; /* case (3) or (1) */
 974         else if (dash_dash_pos >= 2)
 975                 die(_("only one reference expected, %d given."), dash_dash_pos);
 976
 977         if (!strcmp(arg, "-"))
 978                 arg = "@{-1}";
 979
 980         if (get_oid_mb(arg, rev)) {
 981                 /*
 982                  * Either case (3) or (4), with <something> not being
 983                  * a commit, or an attempt to use case (1) with an
 984                  * invalid ref.
 985                  *
 986                  * It's likely an error, but we need to find out if
 987                  * we should auto-create the branch, case (3).(b).
 988                  */
 989                 int recover_with_dwim = dwim_new_local_branch_ok;
 990
 991                 if (!has_dash_dash &&
 992                     (check_filename(opts->prefix, arg) || !no_wildcard(arg)))
 993                         recover_with_dwim = 0;
 994                 /*
 995                  * Accept "git checkout foo" and "git checkout foo --"
 996                  * as candidates for dwim.
 997                  */
 998                 if (!(argc == 1 && !has_dash_dash) &&
 999                     !(argc == 2 && has_dash_dash))
1000                         recover_with_dwim = 0;
1001
1002                 if (recover_with_dwim) {
1003                         const char *remote = unique_tracking_name(arg, rev);
1004                         if (remote) {
1005                                 *new_branch = arg;
1006                                 arg = remote;
1007                                 /* DWIMmed to create local branch, case (3).(b) */
1008                         } else {
1009                                 recover_with_dwim = 0;
1010                         }
1011                 }
1012
1013                 if (!recover_with_dwim) {
1014                         if (has_dash_dash)
1015                                 die(_("invalid reference: %s"), arg);
1016                         return argcount;
1017                 }
1018         }
1019
1020         /* we can't end up being in (2) anymore, eat the argument */
1021         argcount++;
1022         argv++;
1023         argc--;
1024
1025         new->name = arg;
1026         setup_branch_path(new);
1027
1028         if (!check_refname_format(new->path, 0) &&
1029             !read_ref(new->path, branch_rev.hash))
1030                 oidcpy(rev, &branch_rev);
1031         else
1032                 new->path = NULL; /* not an existing branch */
1033
1034         new->commit = lookup_commit_reference_gently(rev, 1);
1035         if (!new->commit) {
1036                 /* not a commit */
1037                 *source_tree = parse_tree_indirect(rev);
1038         } else {
1039                 parse_commit_or_die(new->commit);
1040                 *source_tree = new->commit->tree;
1041         }
1042
1043         if (!*source_tree)                   /* case (1): want a tree */
1044                 die(_("reference is not a tree: %s"), arg);
1045         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1046                 /*
1047                  * Do not complain the most common case
1048                  *      git checkout branch
1049                  * even if there happen to be a file called 'branch';
1050                  * it would be extremely annoying.
1051                  */
1052                 if (argc)
1053                         verify_non_filename(opts->prefix, arg);
1054         } else {
1055                 argcount++;
1056                 argv++;
1057                 argc--;
1058         }
1059
1060         return argcount;
1061 }
1062
1063 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1064 {
1065         int status;
1066         struct strbuf branch_ref = STRBUF_INIT;
1067
1068         if (!opts->new_branch)
1069                 die(_("You are on a branch yet to be born"));
1070         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1071         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1072         strbuf_release(&branch_ref);
1073         if (!opts->quiet)
1074                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1075                         opts->new_branch);
1076         return status;
1077 }
1078
1079 static int checkout_branch(struct checkout_opts *opts,
1080                            struct branch_info *new)
1081 {
1082         if (opts->pathspec.nr)
1083                 die(_("paths cannot be used with switching branches"));
1084
1085         if (opts->patch_mode)
1086                 die(_("'%s' cannot be used with switching branches"),
1087                     "--patch");
1088
1089         if (opts->writeout_stage)
1090                 die(_("'%s' cannot be used with switching branches"),
1091                     "--ours/--theirs");
1092
1093         if (opts->force && opts->merge)
1094                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1095
1096         if (opts->force_detach && opts->new_branch)
1097                 die(_("'%s' cannot be used with '%s'"),
1098                     "--detach", "-b/-B/--orphan");
1099
1100         if (opts->new_orphan_branch) {
1101                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1102                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1103         } else if (opts->force_detach) {
1104                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1105                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1106         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1107                 opts->track = git_branch_track;
1108
1109         if (new->name && !new->commit)
1110                 die(_("Cannot switch branch to a non-commit '%s'"),
1111                     new->name);
1112
1113         if (new->path && !opts->force_detach && !opts->new_branch &&
1114             !opts->ignore_other_worktrees) {
1115                 struct object_id oid;
1116                 int flag;
1117                 char *head_ref = resolve_refdup("HEAD", 0, oid.hash, &flag);
1118                 if (head_ref &&
1119                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
1120                         die_if_checked_out(new->path, 1);
1121                 free(head_ref);
1122         }
1123
1124         if (!new->commit && opts->new_branch) {
1125                 struct object_id rev;
1126                 int flag;
1127
1128                 if (!read_ref_full("HEAD", 0, rev.hash, &flag) &&
1129                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1130                         return switch_unborn_to_new_branch(opts);
1131         }
1132         return switch_branches(opts, new);
1133 }
1134
1135 int cmd_checkout(int argc, const char **argv, const char *prefix)
1136 {
1137         struct checkout_opts opts;
1138         struct branch_info new;
1139         char *conflict_style = NULL;
1140         int dwim_new_local_branch = 1;
1141         struct option options[] = {
1142                 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1143                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1144                            N_("create and checkout a new branch")),
1145                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1146                            N_("create/reset and checkout a branch")),
1147                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1148                 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1149                 OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
1150                         BRANCH_TRACK_EXPLICIT),
1151                 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1152                 OPT_SET_INT('2', "ours", &opts.writeout_stage, N_("checkout our version for unmerged files"),
1153                             2),
1154                 OPT_SET_INT('3', "theirs", &opts.writeout_stage, N_("checkout their version for unmerged files"),
1155                             3),
1156                 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)")),
1157                 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1158                 OPT_BOOL(0, "overwrite-ignore", &opts.overwrite_ignore, N_("update ignored files (default)")),
1159                 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1160                            N_("conflict style (merge or diff3)")),
1161                 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1162                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1163                          N_("do not limit pathspecs to sparse entries only")),
1164                 OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
1165                                 N_("second guess 'git checkout <no-such-branch>'")),
1166                 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1167                          N_("do not check if another worktree is holding the given ref")),
1168                 { OPTION_CALLBACK, 0, "recurse-submodules", NULL,
1169                             "checkout", "control recursive updating of submodules",
1170                             PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
1171                 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1172                 OPT_END(),
1173         };
1174
1175         memset(&opts, 0, sizeof(opts));
1176         memset(&new, 0, sizeof(new));
1177         opts.overwrite_ignore = 1;
1178         opts.prefix = prefix;
1179         opts.show_progress = -1;
1180
1181         gitmodules_config();
1182         git_config(git_checkout_config, &opts);
1183
1184         opts.track = BRANCH_TRACK_UNSPECIFIED;
1185
1186         argc = parse_options(argc, argv, prefix, options, checkout_usage,
1187                              PARSE_OPT_KEEP_DASHDASH);
1188
1189         if (opts.show_progress < 0) {
1190                 if (opts.quiet)
1191                         opts.show_progress = 0;
1192                 else
1193                         opts.show_progress = isatty(2);
1194         }
1195
1196         if (conflict_style) {
1197                 opts.merge = 1; /* implied */
1198                 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1199         }
1200
1201         if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1202                 die(_("-b, -B and --orphan are mutually exclusive"));
1203
1204         /*
1205          * From here on, new_branch will contain the branch to be checked out,
1206          * and new_branch_force and new_orphan_branch will tell us which one of
1207          * -b/-B/--orphan is being used.
1208          */
1209         if (opts.new_branch_force)
1210                 opts.new_branch = opts.new_branch_force;
1211
1212         if (opts.new_orphan_branch)
1213                 opts.new_branch = opts.new_orphan_branch;
1214
1215         /* --track without -b/-B/--orphan should DWIM */
1216         if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1217                 const char *argv0 = argv[0];
1218                 if (!argc || !strcmp(argv0, "--"))
1219                         die (_("--track needs a branch name"));
1220                 skip_prefix(argv0, "refs/", &argv0);
1221                 skip_prefix(argv0, "remotes/", &argv0);
1222                 argv0 = strchr(argv0, '/');
1223                 if (!argv0 || !argv0[1])
1224                         die (_("Missing branch name; try -b"));
1225                 opts.new_branch = argv0 + 1;
1226         }
1227
1228         /*
1229          * Extract branch name from command line arguments, so
1230          * all that is left is pathspecs.
1231          *
1232          * Handle
1233          *
1234          *  1) git checkout <tree> -- [<paths>]
1235          *  2) git checkout -- [<paths>]
1236          *  3) git checkout <something> [<paths>]
1237          *
1238          * including "last branch" syntax and DWIM-ery for names of
1239          * remote branches, erroring out for invalid or ambiguous cases.
1240          */
1241         if (argc) {
1242                 struct object_id rev;
1243                 int dwim_ok =
1244                         !opts.patch_mode &&
1245                         dwim_new_local_branch &&
1246                         opts.track == BRANCH_TRACK_UNSPECIFIED &&
1247                         !opts.new_branch;
1248                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1249                                              &new, &opts, &rev);
1250                 argv += n;
1251                 argc -= n;
1252         }
1253
1254         if (argc) {
1255                 parse_pathspec(&opts.pathspec, 0,
1256                                opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1257                                prefix, argv);
1258
1259                 if (!opts.pathspec.nr)
1260                         die(_("invalid path specification"));
1261
1262                 /*
1263                  * Try to give more helpful suggestion.
1264                  * new_branch && argc > 1 will be caught later.
1265                  */
1266                 if (opts.new_branch && argc == 1)
1267                         die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1268                                 argv[0], opts.new_branch);
1269
1270                 if (opts.force_detach)
1271                         die(_("git checkout: --detach does not take a path argument '%s'"),
1272                             argv[0]);
1273
1274                 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1275                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1276                               "checking out of the index."));
1277         }
1278
1279         if (opts.new_branch) {
1280                 struct strbuf buf = STRBUF_INIT;
1281
1282                 opts.branch_exists =
1283                         validate_new_branchname(opts.new_branch, &buf,
1284                                                 !!opts.new_branch_force,
1285                                                 !!opts.new_branch_force);
1286
1287                 strbuf_release(&buf);
1288         }
1289
1290         if (opts.patch_mode || opts.pathspec.nr)
1291                 return checkout_paths(&opts, new.name);
1292         else
1293                 return checkout_branch(&opts, &new);
1294 }