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

   1 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   2 #include "builtin.h"
   3 #include "advice.h"
   4 #include "blob.h"
   5 #include "branch.h"
   6 #include "cache-tree.h"
   7 #include "checkout.h"
   8 #include "commit.h"
   9 #include "config.h"
  10 #include "diff.h"
  11 #include "dir.h"
  12 #include "ll-merge.h"
  13 #include "lockfile.h"
  14 #include "merge-recursive.h"
  15 #include "object-store.h"
  16 #include "parse-options.h"
  17 #include "refs.h"
  18 #include "remote.h"
  19 #include "resolve-undo.h"
  20 #include "revision.h"
  21 #include "run-command.h"
  22 #include "submodule.h"
  23 #include "submodule-config.h"
  24 #include "tree.h"
  25 #include "tree-walk.h"
  26 #include "unpack-trees.h"
  27 #include "wt-status.h"
  28 #include "xdiff-interface.h"
  29 #include "entry.h"
  30
  31 static const char * const checkout_usage[] = {
  32         N_("git checkout [<options>] <branch>"),
  33         N_("git checkout [<options>] [<branch>] -- <file>..."),
  34         NULL,
  35 };
  36
  37 static const char * const switch_branch_usage[] = {
  38         N_("git switch [<options>] [<branch>]"),
  39         NULL,
  40 };
  41
  42 static const char * const restore_usage[] = {
  43         N_("git restore [<options>] [--source=<branch>] <file>..."),
  44         NULL,
  45 };
  46
  47 struct checkout_opts {
  48         int patch_mode;
  49         int quiet;
  50         int merge;
  51         int force;
  52         int force_detach;
  53         int implicit_detach;
  54         int writeout_stage;
  55         int overwrite_ignore;
  56         int ignore_skipworktree;
  57         int ignore_other_worktrees;
  58         int show_progress;
  59         int count_checkout_paths;
  60         int overlay_mode;
  61         int dwim_new_local_branch;
  62         int discard_changes;
  63         int accept_ref;
  64         int accept_pathspec;
  65         int switch_branch_doing_nothing_is_ok;
  66         int only_merge_on_switching_branches;
  67         int can_switch_when_in_progress;
  68         int orphan_from_empty_tree;
  69         int empty_pathspec_ok;
  70         int checkout_index;
  71         int checkout_worktree;
  72         const char *ignore_unmerged_opt;
  73         int ignore_unmerged;
  74         int pathspec_file_nul;
  75         const char *pathspec_from_file;
  76
  77         const char *new_branch;
  78         const char *new_branch_force;
  79         const char *new_orphan_branch;
  80         int new_branch_log;
  81         enum branch_track track;
  82         struct diff_options diff_options;
  83         char *conflict_style;
  84
  85         int branch_exists;
  86         const char *prefix;
  87         struct pathspec pathspec;
  88         const char *from_treeish;
  89         struct tree *source_tree;
  90 };
  91
  92 struct branch_info {
  93         const char *name; /* The short name used */
  94         const char *path; /* The full name of a real branch */
  95         struct commit *commit; /* The named commit */
  96         char *refname; /* The full name of the ref being checked out. */
  97         struct object_id oid; /* The object ID of the commit being checked out. */
  98         /*
  99          * if not null the branch is detached because it's already
 100          * checked out in this checkout
 101          */
 102         char *checkout;
 103 };
 104
 105 static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
 106                               int changed)
 107 {
 108         return run_hook_le(NULL, "post-checkout",
 109                            oid_to_hex(old_commit ? &old_commit->object.oid : &null_oid),
 110                            oid_to_hex(new_commit ? &new_commit->object.oid : &null_oid),
 111                            changed ? "1" : "0", NULL);
 112         /* "new_commit" can be NULL when checking out from the index before
 113            a commit exists. */
 114
 115 }
 116
 117 static int update_some(const struct object_id *oid, struct strbuf *base,
 118                 const char *pathname, unsigned mode, void *context)
 119 {
 120         int len;
 121         struct cache_entry *ce;
 122         int pos;
 123
 124         if (S_ISDIR(mode))
 125                 return READ_TREE_RECURSIVE;
 126
 127         len = base->len + strlen(pathname);
 128         ce = make_empty_cache_entry(&the_index, len);
 129         oidcpy(&ce->oid, oid);
 130         memcpy(ce->name, base->buf, base->len);
 131         memcpy(ce->name + base->len, pathname, len - base->len);
 132         ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
 133         ce->ce_namelen = len;
 134         ce->ce_mode = create_ce_mode(mode);
 135
 136         /*
 137          * If the entry is the same as the current index, we can leave the old
 138          * entry in place. Whether it is UPTODATE or not, checkout_entry will
 139          * do the right thing.
 140          */
 141         pos = cache_name_pos(ce->name, ce->ce_namelen);
 142         if (pos >= 0) {
 143                 struct cache_entry *old = active_cache[pos];
 144                 if (ce->ce_mode == old->ce_mode &&
 145                     !ce_intent_to_add(old) &&
 146                     oideq(&ce->oid, &old->oid)) {
 147                         old->ce_flags |= CE_UPDATE;
 148                         discard_cache_entry(ce);
 149                         return 0;
 150                 }
 151         }
 152
 153         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 154         return 0;
 155 }
 156
 157 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
 158 {
 159         read_tree(the_repository, tree,
 160                   pathspec, update_some, NULL);
 161
 162         /* update the index with the given tree's info
 163          * for all args, expanding wildcards, and exit
 164          * with any non-zero return code.
 165          */
 166         return 0;
 167 }
 168
 169 static int skip_same_name(const struct cache_entry *ce, int pos)
 170 {
 171         while (++pos < active_nr &&
 172                !strcmp(active_cache[pos]->name, ce->name))
 173                 ; /* skip */
 174         return pos;
 175 }
 176
 177 static int check_stage(int stage, const struct cache_entry *ce, int pos,
 178                        int overlay_mode)
 179 {
 180         while (pos < active_nr &&
 181                !strcmp(active_cache[pos]->name, ce->name)) {
 182                 if (ce_stage(active_cache[pos]) == stage)
 183                         return 0;
 184                 pos++;
 185         }
 186         if (!overlay_mode)
 187                 return 0;
 188         if (stage == 2)
 189                 return error(_("path '%s' does not have our version"), ce->name);
 190         else
 191                 return error(_("path '%s' does not have their version"), ce->name);
 192 }
 193
 194 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 195 {
 196         unsigned seen = 0;
 197         const char *name = ce->name;
 198
 199         while (pos < active_nr) {
 200                 ce = active_cache[pos];
 201                 if (strcmp(name, ce->name))
 202                         break;
 203                 seen |= (1 << ce_stage(ce));
 204                 pos++;
 205         }
 206         if ((stages & seen) != stages)
 207                 return error(_("path '%s' does not have all necessary versions"),
 208                              name);
 209         return 0;
 210 }
 211
 212 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 213                           const struct checkout *state, int *nr_checkouts,
 214                           int overlay_mode)
 215 {
 216         while (pos < active_nr &&
 217                !strcmp(active_cache[pos]->name, ce->name)) {
 218                 if (ce_stage(active_cache[pos]) == stage)
 219                         return checkout_entry(active_cache[pos], state,
 220                                               NULL, nr_checkouts);
 221                 pos++;
 222         }
 223         if (!overlay_mode) {
 224                 unlink_entry(ce);
 225                 return 0;
 226         }
 227         if (stage == 2)
 228                 return error(_("path '%s' does not have our version"), ce->name);
 229         else
 230                 return error(_("path '%s' does not have their version"), ce->name);
 231 }
 232
 233 static int checkout_merged(int pos, const struct checkout *state, int *nr_checkouts)
 234 {
 235         struct cache_entry *ce = active_cache[pos];
 236         const char *path = ce->name;
 237         mmfile_t ancestor, ours, theirs;
 238         int status;
 239         struct object_id oid;
 240         mmbuffer_t result_buf;
 241         struct object_id threeway[3];
 242         unsigned mode = 0;
 243         struct ll_merge_options ll_opts;
 244         int renormalize = 0;
 245
 246         memset(threeway, 0, sizeof(threeway));
 247         while (pos < active_nr) {
 248                 int stage;
 249                 stage = ce_stage(ce);
 250                 if (!stage || strcmp(path, ce->name))
 251                         break;
 252                 oidcpy(&threeway[stage - 1], &ce->oid);
 253                 if (stage == 2)
 254                         mode = create_ce_mode(ce->ce_mode);
 255                 pos++;
 256                 ce = active_cache[pos];
 257         }
 258         if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 259                 return error(_("path '%s' does not have necessary versions"), path);
 260
 261         read_mmblob(&ancestor, &threeway[0]);
 262         read_mmblob(&ours, &threeway[1]);
 263         read_mmblob(&theirs, &threeway[2]);
 264
 265         memset(&ll_opts, 0, sizeof(ll_opts));
 266         git_config_get_bool("merge.renormalize", &renormalize);
 267         ll_opts.renormalize = renormalize;
 268         status = ll_merge(&result_buf, path, &ancestor, "base",
 269                           &ours, "ours", &theirs, "theirs",
 270                           state->istate, &ll_opts);
 271         free(ancestor.ptr);
 272         free(ours.ptr);
 273         free(theirs.ptr);
 274         if (status < 0 || !result_buf.ptr) {
 275                 free(result_buf.ptr);
 276                 return error(_("path '%s': cannot merge"), path);
 277         }
 278
 279         /*
 280          * NEEDSWORK:
 281          * There is absolutely no reason to write this as a blob object
 282          * and create a phony cache entry.  This hack is primarily to get
 283          * to the write_entry() machinery that massages the contents to
 284          * work-tree format and writes out which only allows it for a
 285          * cache entry.  The code in write_entry() needs to be refactored
 286          * to allow us to feed a <buffer, size, mode> instead of a cache
 287          * entry.  Such a refactoring would help merge_recursive as well
 288          * (it also writes the merge result to the object database even
 289          * when it may contain conflicts).
 290          */
 291         if (write_object_file(result_buf.ptr, result_buf.size, blob_type, &oid))
 292                 die(_("Unable to add merge result for '%s'"), path);
 293         free(result_buf.ptr);
 294         ce = make_transient_cache_entry(mode, &oid, path, 2);
 295         if (!ce)
 296                 die(_("make_cache_entry failed for path '%s'"), path);
 297         status = checkout_entry(ce, state, NULL, nr_checkouts);
 298         discard_cache_entry(ce);
 299         return status;
 300 }
 301
 302 static void mark_ce_for_checkout_overlay(struct cache_entry *ce,
 303                                          char *ps_matched,
 304                                          const struct checkout_opts *opts)
 305 {
 306         ce->ce_flags &= ~CE_MATCHED;
 307         if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 308                 return;
 309         if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 310                 /*
 311                  * "git checkout tree-ish -- path", but this entry
 312                  * is in the original index but is not in tree-ish
 313                  * or does not match the pathspec; it will not be
 314                  * checked out to the working tree.  We will not do
 315                  * anything to this entry at all.
 316                  */
 317                 return;
 318         /*
 319          * Either this entry came from the tree-ish we are
 320          * checking the paths out of, or we are checking out
 321          * of the index.
 322          *
 323          * If it comes from the tree-ish, we already know it
 324          * matches the pathspec and could just stamp
 325          * CE_MATCHED to it from update_some(). But we still
 326          * need ps_matched and read_tree (and
 327          * eventually tree_entry_interesting) cannot fill
 328          * ps_matched yet. Once it can, we can avoid calling
 329          * match_pathspec() for _all_ entries when
 330          * opts->source_tree != NULL.
 331          */
 332         if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched))
 333                 ce->ce_flags |= CE_MATCHED;
 334 }
 335
 336 static void mark_ce_for_checkout_no_overlay(struct cache_entry *ce,
 337                                             char *ps_matched,
 338                                             const struct checkout_opts *opts)
 339 {
 340         ce->ce_flags &= ~CE_MATCHED;
 341         if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 342                 return;
 343         if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched)) {
 344                 ce->ce_flags |= CE_MATCHED;
 345                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 346                         /*
 347                          * In overlay mode, but the path is not in
 348                          * tree-ish, which means we should remove it
 349                          * from the index and the working tree.
 350                          */
 351                         ce->ce_flags |= CE_REMOVE | CE_WT_REMOVE;
 352         }
 353 }
 354
 355 static int checkout_worktree(const struct checkout_opts *opts,
 356                              const struct branch_info *info)
 357 {
 358         struct checkout state = CHECKOUT_INIT;
 359         int nr_checkouts = 0, nr_unmerged = 0;
 360         int errs = 0;
 361         int pos;
 362
 363         state.force = 1;
 364         state.refresh_cache = 1;
 365         state.istate = &the_index;
 366
 367         init_checkout_metadata(&state.meta, info->refname,
 368                                info->commit ? &info->commit->object.oid : &info->oid,
 369                                NULL);
 370
 371         enable_delayed_checkout(&state);
 372
 373         /* TODO: audit for interaction with sparse-index. */
 374         ensure_full_index(&the_index);
 375         for (pos = 0; pos < active_nr; pos++) {
 376                 struct cache_entry *ce = active_cache[pos];
 377                 if (ce->ce_flags & CE_MATCHED) {
 378                         if (!ce_stage(ce)) {
 379                                 errs |= checkout_entry(ce, &state,
 380                                                        NULL, &nr_checkouts);
 381                                 continue;
 382                         }
 383                         if (opts->writeout_stage)
 384                                 errs |= checkout_stage(opts->writeout_stage,
 385                                                        ce, pos,
 386                                                        &state,
 387                                                        &nr_checkouts, opts->overlay_mode);
 388                         else if (opts->merge)
 389                                 errs |= checkout_merged(pos, &state,
 390                                                         &nr_unmerged);
 391                         pos = skip_same_name(ce, pos) - 1;
 392                 }
 393         }
 394         remove_marked_cache_entries(&the_index, 1);
 395         remove_scheduled_dirs();
 396         errs |= finish_delayed_checkout(&state, &nr_checkouts);
 397
 398         if (opts->count_checkout_paths) {
 399                 if (nr_unmerged)
 400                         fprintf_ln(stderr, Q_("Recreated %d merge conflict",
 401                                               "Recreated %d merge conflicts",
 402                                               nr_unmerged),
 403                                    nr_unmerged);
 404                 if (opts->source_tree)
 405                         fprintf_ln(stderr, Q_("Updated %d path from %s",
 406                                               "Updated %d paths from %s",
 407                                               nr_checkouts),
 408                                    nr_checkouts,
 409                                    find_unique_abbrev(&opts->source_tree->object.oid,
 410                                                       DEFAULT_ABBREV));
 411                 else if (!nr_unmerged || nr_checkouts)
 412                         fprintf_ln(stderr, Q_("Updated %d path from the index",
 413                                               "Updated %d paths from the index",
 414                                               nr_checkouts),
 415                                    nr_checkouts);
 416         }
 417
 418         return errs;
 419 }
 420
 421 static int checkout_paths(const struct checkout_opts *opts,
 422                           const struct branch_info *new_branch_info)
 423 {
 424         int pos;
 425         static char *ps_matched;
 426         struct object_id rev;
 427         struct commit *head;
 428         int errs = 0;
 429         struct lock_file lock_file = LOCK_INIT;
 430         int checkout_index;
 431
 432         trace2_cmd_mode(opts->patch_mode ? "patch" : "path");
 433
 434         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 435                 die(_("'%s' cannot be used with updating paths"), "--track");
 436
 437         if (opts->new_branch_log)
 438                 die(_("'%s' cannot be used with updating paths"), "-l");
 439
 440         if (opts->ignore_unmerged && opts->patch_mode)
 441                 die(_("'%s' cannot be used with updating paths"),
 442                     opts->ignore_unmerged_opt);
 443
 444         if (opts->force_detach)
 445                 die(_("'%s' cannot be used with updating paths"), "--detach");
 446
 447         if (opts->merge && opts->patch_mode)
 448                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 449
 450         if (opts->ignore_unmerged && opts->merge)
 451                 die(_("'%s' cannot be used with %s"),
 452                     opts->ignore_unmerged_opt, "-m");
 453
 454         if (opts->new_branch)
 455                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 456                     opts->new_branch);
 457
 458         if (!opts->checkout_worktree && !opts->checkout_index)
 459                 die(_("neither '%s' or '%s' is specified"),
 460                     "--staged", "--worktree");
 461
 462         if (!opts->checkout_worktree && !opts->from_treeish)
 463                 die(_("'%s' must be used when '%s' is not specified"),
 464                     "--worktree", "--source");
 465
 466         if (opts->checkout_index && !opts->checkout_worktree &&
 467             opts->writeout_stage)
 468                 die(_("'%s' or '%s' cannot be used with %s"),
 469                     "--ours", "--theirs", "--staged");
 470
 471         if (opts->checkout_index && !opts->checkout_worktree &&
 472             opts->merge)
 473                 die(_("'%s' or '%s' cannot be used with %s"),
 474                     "--merge", "--conflict", "--staged");
 475
 476         if (opts->patch_mode) {
 477                 const char *patch_mode;
 478                 const char *rev = new_branch_info->name;
 479                 char rev_oid[GIT_MAX_HEXSZ + 1];
 480
 481                 /*
 482                  * Since rev can be in the form of `<a>...<b>` (which is not
 483                  * recognized by diff-index), we will always replace the name
 484                  * with the hex of the commit (whether it's in `...` form or
 485                  * not) for the run_add_interactive() machinery to work
 486                  * properly. However, there is special logic for the HEAD case
 487                  * so we mustn't replace that.  Also, when we were given a
 488                  * tree-object, new_branch_info->commit would be NULL, but we
 489                  * do not have to do any replacement, either.
 490                  */
 491                 if (rev && new_branch_info->commit && strcmp(rev, "HEAD"))
 492                         rev = oid_to_hex_r(rev_oid, &new_branch_info->commit->object.oid);
 493
 494                 if (opts->checkout_index && opts->checkout_worktree)
 495                         patch_mode = "--patch=checkout";
 496                 else if (opts->checkout_index && !opts->checkout_worktree)
 497                         patch_mode = "--patch=reset";
 498                 else if (!opts->checkout_index && opts->checkout_worktree)
 499                         patch_mode = "--patch=worktree";
 500                 else
 501                         BUG("either flag must have been set, worktree=%d, index=%d",
 502                             opts->checkout_worktree, opts->checkout_index);
 503                 return run_add_interactive(rev, patch_mode, &opts->pathspec);
 504         }
 505
 506         repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);
 507         if (read_cache_preload(&opts->pathspec) < 0)
 508                 return error(_("index file corrupt"));
 509
 510         if (opts->source_tree)
 511                 read_tree_some(opts->source_tree, &opts->pathspec);
 512
 513         ps_matched = xcalloc(opts->pathspec.nr, 1);
 514
 515         /*
 516          * Make sure all pathspecs participated in locating the paths
 517          * to be checked out.
 518          */
 519         /* TODO: audit for interaction with sparse-index. */
 520         ensure_full_index(&the_index);
 521         for (pos = 0; pos < active_nr; pos++)
 522                 if (opts->overlay_mode)
 523                         mark_ce_for_checkout_overlay(active_cache[pos],
 524                                                      ps_matched,
 525                                                      opts);
 526                 else
 527                         mark_ce_for_checkout_no_overlay(active_cache[pos],
 528                                                         ps_matched,
 529                                                         opts);
 530
 531         if (report_path_error(ps_matched, &opts->pathspec)) {
 532                 free(ps_matched);
 533                 return 1;
 534         }
 535         free(ps_matched);
 536
 537         /* "checkout -m path" to recreate conflicted state */
 538         if (opts->merge)
 539                 unmerge_marked_index(&the_index);
 540
 541         /* Any unmerged paths? */
 542         for (pos = 0; pos < active_nr; pos++) {
 543                 const struct cache_entry *ce = active_cache[pos];
 544                 if (ce->ce_flags & CE_MATCHED) {
 545                         if (!ce_stage(ce))
 546                                 continue;
 547                         if (opts->ignore_unmerged) {
 548                                 if (!opts->quiet)
 549                                         warning(_("path '%s' is unmerged"), ce->name);
 550                         } else if (opts->writeout_stage) {
 551                                 errs |= check_stage(opts->writeout_stage, ce, pos, opts->overlay_mode);
 552                         } else if (opts->merge) {
 553                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 554                         } else {
 555                                 errs = 1;
 556                                 error(_("path '%s' is unmerged"), ce->name);
 557                         }
 558                         pos = skip_same_name(ce, pos) - 1;
 559                 }
 560         }
 561         if (errs)
 562                 return 1;
 563
 564         /* Now we are committed to check them out */
 565         if (opts->checkout_worktree)
 566                 errs |= checkout_worktree(opts, new_branch_info);
 567         else
 568                 remove_marked_cache_entries(&the_index, 1);
 569
 570         /*
 571          * Allow updating the index when checking out from the index.
 572          * This is to save new stat info.
 573          */
 574         if (opts->checkout_worktree && !opts->checkout_index && !opts->source_tree)
 575                 checkout_index = 1;
 576         else
 577                 checkout_index = opts->checkout_index;
 578
 579         if (checkout_index) {
 580                 if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 581                         die(_("unable to write new index file"));
 582         } else {
 583                 /*
 584                  * NEEDSWORK: if --worktree is not specified, we
 585                  * should save stat info of checked out files in the
 586                  * index to avoid the next (potentially costly)
 587                  * refresh. But it's a bit tricker to do...
 588                  */
 589                 rollback_lock_file(&lock_file);
 590         }
 591
 592         read_ref_full("HEAD", 0, &rev, NULL);
 593         head = lookup_commit_reference_gently(the_repository, &rev, 1);
 594
 595         errs |= post_checkout_hook(head, head, 0);
 596         return errs;
 597 }
 598
 599 static void show_local_changes(struct object *head,
 600                                const struct diff_options *opts)
 601 {
 602         struct rev_info rev;
 603         /* I think we want full paths, even if we're in a subdirectory. */
 604         repo_init_revisions(the_repository, &rev, NULL);
 605         rev.diffopt.flags = opts->flags;
 606         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 607         diff_setup_done(&rev.diffopt);
 608         add_pending_object(&rev, head, NULL);
 609         run_diff_index(&rev, 0);
 610 }
 611
 612 static void describe_detached_head(const char *msg, struct commit *commit)
 613 {
 614         struct strbuf sb = STRBUF_INIT;
 615
 616         if (!parse_commit(commit))
 617                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 618         if (print_sha1_ellipsis()) {
 619                 fprintf(stderr, "%s %s... %s\n", msg,
 620                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 621         } else {
 622                 fprintf(stderr, "%s %s %s\n", msg,
 623                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 624         }
 625         strbuf_release(&sb);
 626 }
 627
 628 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 629                       int worktree, int *writeout_error,
 630                       struct branch_info *info)
 631 {
 632         struct unpack_trees_options opts;
 633         struct tree_desc tree_desc;
 634
 635         memset(&opts, 0, sizeof(opts));
 636         opts.head_idx = -1;
 637         opts.update = worktree;
 638         opts.skip_unmerged = !worktree;
 639         opts.reset = 1;
 640         opts.merge = 1;
 641         opts.fn = oneway_merge;
 642         opts.verbose_update = o->show_progress;
 643         opts.src_index = &the_index;
 644         opts.dst_index = &the_index;
 645         init_checkout_metadata(&opts.meta, info->refname,
 646                                info->commit ? &info->commit->object.oid : &null_oid,
 647                                NULL);
 648         parse_tree(tree);
 649         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 650         switch (unpack_trees(1, &tree_desc, &opts)) {
 651         case -2:
 652                 *writeout_error = 1;
 653                 /*
 654                  * We return 0 nevertheless, as the index is all right
 655                  * and more importantly we have made best efforts to
 656                  * update paths in the work tree, and we cannot revert
 657                  * them.
 658                  */
 659                 /* fallthrough */
 660         case 0:
 661                 return 0;
 662         default:
 663                 return 128;
 664         }
 665 }
 666
 667 static void setup_branch_path(struct branch_info *branch)
 668 {
 669         struct strbuf buf = STRBUF_INIT;
 670
 671         /*
 672          * If this is a ref, resolve it; otherwise, look up the OID for our
 673          * expression.  Failure here is okay.
 674          */
 675         if (!dwim_ref(branch->name, strlen(branch->name), &branch->oid, &branch->refname, 0))
 676                 repo_get_oid_committish(the_repository, branch->name, &branch->oid);
 677
 678         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 679         if (strcmp(buf.buf, branch->name))
 680                 branch->name = xstrdup(buf.buf);
 681         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 682         branch->path = strbuf_detach(&buf, NULL);
 683 }
 684
 685 static int merge_working_tree(const struct checkout_opts *opts,
 686                               struct branch_info *old_branch_info,
 687                               struct branch_info *new_branch_info,
 688                               int *writeout_error)
 689 {
 690         int ret;
 691         struct lock_file lock_file = LOCK_INIT;
 692         struct tree *new_tree;
 693
 694         hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 695         if (read_cache_preload(NULL) < 0)
 696                 return error(_("index file corrupt"));
 697
 698         resolve_undo_clear();
 699         if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
 700                 if (new_branch_info->commit)
 701                         BUG("'switch --orphan' should never accept a commit as starting point");
 702                 new_tree = parse_tree_indirect(the_hash_algo->empty_tree);
 703         } else
 704                 new_tree = get_commit_tree(new_branch_info->commit);
 705         if (opts->discard_changes) {
 706                 ret = reset_tree(new_tree, opts, 1, writeout_error, new_branch_info);
 707                 if (ret)
 708                         return ret;
 709         } else {
 710                 struct tree_desc trees[2];
 711                 struct tree *tree;
 712                 struct unpack_trees_options topts;
 713
 714                 memset(&topts, 0, sizeof(topts));
 715                 topts.head_idx = -1;
 716                 topts.src_index = &the_index;
 717                 topts.dst_index = &the_index;
 718
 719                 setup_unpack_trees_porcelain(&topts, "checkout");
 720
 721                 refresh_cache(REFRESH_QUIET);
 722
 723                 if (unmerged_cache()) {
 724                         error(_("you need to resolve your current index first"));
 725                         return 1;
 726                 }
 727
 728                 /* 2-way merge to the new branch */
 729                 topts.initial_checkout = is_cache_unborn();
 730                 topts.update = 1;
 731                 topts.merge = 1;
 732                 topts.quiet = opts->merge && old_branch_info->commit;
 733                 topts.verbose_update = opts->show_progress;
 734                 topts.fn = twoway_merge;
 735                 init_checkout_metadata(&topts.meta, new_branch_info->refname,
 736                                        new_branch_info->commit ?
 737                                        &new_branch_info->commit->object.oid :
 738                                        &new_branch_info->oid, NULL);
 739                 if (opts->overwrite_ignore) {
 740                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 741                         topts.dir->flags |= DIR_SHOW_IGNORED;
 742                         setup_standard_excludes(topts.dir);
 743                 }
 744                 tree = parse_tree_indirect(old_branch_info->commit ?
 745                                            &old_branch_info->commit->object.oid :
 746                                            the_hash_algo->empty_tree);
 747                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 748                 parse_tree(new_tree);
 749                 tree = new_tree;
 750                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 751
 752                 ret = unpack_trees(2, trees, &topts);
 753                 clear_unpack_trees_porcelain(&topts);
 754                 if (ret == -1) {
 755                         /*
 756                          * Unpack couldn't do a trivial merge; either
 757                          * give up or do a real merge, depending on
 758                          * whether the merge flag was used.
 759                          */
 760                         struct tree *work;
 761                         struct tree *old_tree;
 762                         struct merge_options o;
 763                         struct strbuf sb = STRBUF_INIT;
 764                         struct strbuf old_commit_shortname = STRBUF_INIT;
 765
 766                         if (!opts->merge)
 767                                 return 1;
 768
 769                         /*
 770                          * Without old_branch_info->commit, the below is the same as
 771                          * the two-tree unpack we already tried and failed.
 772                          */
 773                         if (!old_branch_info->commit)
 774                                 return 1;
 775                         old_tree = get_commit_tree(old_branch_info->commit);
 776
 777                         if (repo_index_has_changes(the_repository, old_tree, &sb))
 778                                 die(_("cannot continue with staged changes in "
 779                                       "the following files:\n%s"), sb.buf);
 780                         strbuf_release(&sb);
 781
 782                         /* Do more real merge */
 783
 784                         /*
 785                          * We update the index fully, then write the
 786                          * tree from the index, then merge the new
 787                          * branch with the current tree, with the old
 788                          * branch as the base. Then we reset the index
 789                          * (but not the working tree) to the new
 790                          * branch, leaving the working tree as the
 791                          * merged version, but skipping unmerged
 792                          * entries in the index.
 793                          */
 794
 795                         add_files_to_cache(NULL, NULL, 0);
 796                         init_merge_options(&o, the_repository);
 797                         o.verbosity = 0;
 798                         work = write_in_core_index_as_tree(the_repository);
 799
 800                         ret = reset_tree(new_tree,
 801                                          opts, 1,
 802                                          writeout_error, new_branch_info);
 803                         if (ret)
 804                                 return ret;
 805                         o.ancestor = old_branch_info->name;
 806                         if (old_branch_info->name == NULL) {
 807                                 strbuf_add_unique_abbrev(&old_commit_shortname,
 808                                                          &old_branch_info->commit->object.oid,
 809                                                          DEFAULT_ABBREV);
 810                                 o.ancestor = old_commit_shortname.buf;
 811                         }
 812                         o.branch1 = new_branch_info->name;
 813                         o.branch2 = "local";
 814                         ret = merge_trees(&o,
 815                                           new_tree,
 816                                           work,
 817                                           old_tree);
 818                         if (ret < 0)
 819                                 exit(128);
 820                         ret = reset_tree(new_tree,
 821                                          opts, 0,
 822                                          writeout_error, new_branch_info);
 823                         strbuf_release(&o.obuf);
 824                         strbuf_release(&old_commit_shortname);
 825                         if (ret)
 826                                 return ret;
 827                 }
 828         }
 829
 830         if (!cache_tree_fully_valid(active_cache_tree))
 831                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 832
 833         if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 834                 die(_("unable to write new index file"));
 835
 836         if (!opts->discard_changes && !opts->quiet && new_branch_info->commit)
 837                 show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
 838
 839         return 0;
 840 }
 841
 842 static void report_tracking(struct branch_info *new_branch_info)
 843 {
 844         struct strbuf sb = STRBUF_INIT;
 845         struct branch *branch = branch_get(new_branch_info->name);
 846
 847         if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL))
 848                 return;
 849         fputs(sb.buf, stdout);
 850         strbuf_release(&sb);
 851 }
 852
 853 static void update_refs_for_switch(const struct checkout_opts *opts,
 854                                    struct branch_info *old_branch_info,
 855                                    struct branch_info *new_branch_info)
 856 {
 857         struct strbuf msg = STRBUF_INIT;
 858         const char *old_desc, *reflog_msg;
 859         if (opts->new_branch) {
 860                 if (opts->new_orphan_branch) {
 861                         char *refname;
 862
 863                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 864                         if (opts->new_branch_log &&
 865                             !should_autocreate_reflog(refname)) {
 866                                 int ret;
 867                                 struct strbuf err = STRBUF_INIT;
 868
 869                                 ret = safe_create_reflog(refname, 1, &err);
 870                                 if (ret) {
 871                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 872                                                 opts->new_orphan_branch, err.buf);
 873                                         strbuf_release(&err);
 874                                         free(refname);
 875                                         return;
 876                                 }
 877                                 strbuf_release(&err);
 878                         }
 879                         free(refname);
 880                 }
 881                 else
 882                         create_branch(the_repository,
 883                                       opts->new_branch, new_branch_info->name,
 884                                       opts->new_branch_force ? 1 : 0,
 885                                       opts->new_branch_force ? 1 : 0,
 886                                       opts->new_branch_log,
 887                                       opts->quiet,
 888                                       opts->track);
 889                 new_branch_info->name = opts->new_branch;
 890                 setup_branch_path(new_branch_info);
 891         }
 892
 893         old_desc = old_branch_info->name;
 894         if (!old_desc && old_branch_info->commit)
 895                 old_desc = oid_to_hex(&old_branch_info->commit->object.oid);
 896
 897         reflog_msg = getenv("GIT_REFLOG_ACTION");
 898         if (!reflog_msg)
 899                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 900                         old_desc ? old_desc : "(invalid)", new_branch_info->name);
 901         else
 902                 strbuf_insertstr(&msg, 0, reflog_msg);
 903
 904         if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
 905                 /* Nothing to do. */
 906         } else if (opts->force_detach || !new_branch_info->path) {      /* No longer on any branch. */
 907                 update_ref(msg.buf, "HEAD", &new_branch_info->commit->object.oid, NULL,
 908                            REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
 909                 if (!opts->quiet) {
 910                         if (old_branch_info->path &&
 911                             advice_detached_head && !opts->force_detach)
 912                                 detach_advice(new_branch_info->name);
 913                         describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
 914                 }
 915         } else if (new_branch_info->path) {     /* Switch branches. */
 916                 if (create_symref("HEAD", new_branch_info->path, msg.buf) < 0)
 917                         die(_("unable to update HEAD"));
 918                 if (!opts->quiet) {
 919                         if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
 920                                 if (opts->new_branch_force)
 921                                         fprintf(stderr, _("Reset branch '%s'\n"),
 922                                                 new_branch_info->name);
 923                                 else
 924                                         fprintf(stderr, _("Already on '%s'\n"),
 925                                                 new_branch_info->name);
 926                         } else if (opts->new_branch) {
 927                                 if (opts->branch_exists)
 928                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new_branch_info->name);
 929                                 else
 930                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new_branch_info->name);
 931                         } else {
 932                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 933                                         new_branch_info->name);
 934                         }
 935                 }
 936                 if (old_branch_info->path && old_branch_info->name) {
 937                         if (!ref_exists(old_branch_info->path) && reflog_exists(old_branch_info->path))
 938                                 delete_reflog(old_branch_info->path);
 939                 }
 940         }
 941         remove_branch_state(the_repository, !opts->quiet);
 942         strbuf_release(&msg);
 943         if (!opts->quiet &&
 944             (new_branch_info->path || (!opts->force_detach && !strcmp(new_branch_info->name, "HEAD"))))
 945                 report_tracking(new_branch_info);
 946 }
 947
 948 static int add_pending_uninteresting_ref(const char *refname,
 949                                          const struct object_id *oid,
 950                                          int flags, void *cb_data)
 951 {
 952         add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 953         return 0;
 954 }
 955
 956 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 957 {
 958         strbuf_addstr(sb, "  ");
 959         strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
 960         strbuf_addch(sb, ' ');
 961         if (!parse_commit(commit))
 962                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 963         strbuf_addch(sb, '\n');
 964 }
 965
 966 #define ORPHAN_CUTOFF 4
 967 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 968 {
 969         struct commit *c, *last = NULL;
 970         struct strbuf sb = STRBUF_INIT;
 971         int lost = 0;
 972         while ((c = get_revision(revs)) != NULL) {
 973                 if (lost < ORPHAN_CUTOFF)
 974                         describe_one_orphan(&sb, c);
 975                 last = c;
 976                 lost++;
 977         }
 978         if (ORPHAN_CUTOFF < lost) {
 979                 int more = lost - ORPHAN_CUTOFF;
 980                 if (more == 1)
 981                         describe_one_orphan(&sb, last);
 982                 else
 983                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 984         }
 985
 986         fprintf(stderr,
 987                 Q_(
 988                 /* The singular version */
 989                 "Warning: you are leaving %d commit behind, "
 990                 "not connected to\n"
 991                 "any of your branches:\n\n"
 992                 "%s\n",
 993                 /* The plural version */
 994                 "Warning: you are leaving %d commits behind, "
 995                 "not connected to\n"
 996                 "any of your branches:\n\n"
 997                 "%s\n",
 998                 /* Give ngettext() the count */
 999                 lost),
1000                 lost,
1001                 sb.buf);
1002         strbuf_release(&sb);
1003
1004         if (advice_detached_head)
1005                 fprintf(stderr,
1006                         Q_(
1007                         /* The singular version */
1008                         "If you want to keep it by creating a new branch, "
1009                         "this may be a good time\nto do so with:\n\n"
1010                         " git branch <new-branch-name> %s\n\n",
1011                         /* The plural version */
1012                         "If you want to keep them by creating a new branch, "
1013                         "this may be a good time\nto do so with:\n\n"
1014                         " git branch <new-branch-name> %s\n\n",
1015                         /* Give ngettext() the count */
1016                         lost),
1017                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
1018 }
1019
1020 /*
1021  * We are about to leave commit that was at the tip of a detached
1022  * HEAD.  If it is not reachable from any ref, this is the last chance
1023  * for the user to do so without resorting to reflog.
1024  */
1025 static void orphaned_commit_warning(struct commit *old_commit, struct commit *new_commit)
1026 {
1027         struct rev_info revs;
1028         struct object *object = &old_commit->object;
1029
1030         repo_init_revisions(the_repository, &revs, NULL);
1031         setup_revisions(0, NULL, &revs, NULL);
1032
1033         object->flags &= ~UNINTERESTING;
1034         add_pending_object(&revs, object, oid_to_hex(&object->oid));
1035
1036         for_each_ref(add_pending_uninteresting_ref, &revs);
1037         if (new_commit)
1038                 add_pending_oid(&revs, "HEAD",
1039                                 &new_commit->object.oid,
1040                                 UNINTERESTING);
1041
1042         if (prepare_revision_walk(&revs))
1043                 die(_("internal error in revision walk"));
1044         if (!(old_commit->object.flags & UNINTERESTING))
1045                 suggest_reattach(old_commit, &revs);
1046         else
1047                 describe_detached_head(_("Previous HEAD position was"), old_commit);
1048
1049         /* Clean up objects used, as they will be reused. */
1050         repo_clear_commit_marks(the_repository, ALL_REV_FLAGS);
1051 }
1052
1053 static int switch_branches(const struct checkout_opts *opts,
1054                            struct branch_info *new_branch_info)
1055 {
1056         int ret = 0;
1057         struct branch_info old_branch_info;
1058         void *path_to_free;
1059         struct object_id rev;
1060         int flag, writeout_error = 0;
1061         int do_merge = 1;
1062
1063         trace2_cmd_mode("branch");
1064
1065         memset(&old_branch_info, 0, sizeof(old_branch_info));
1066         old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
1067         if (old_branch_info.path)
1068                 old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
1069         if (!(flag & REF_ISSYMREF))
1070                 old_branch_info.path = NULL;
1071
1072         if (old_branch_info.path)
1073                 skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
1074
1075         if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
1076                 if (new_branch_info->name)
1077                         BUG("'switch --orphan' should never accept a commit as starting point");
1078                 new_branch_info->commit = NULL;
1079                 new_branch_info->name = "(empty)";
1080                 do_merge = 1;
1081         }
1082
1083         if (!new_branch_info->name) {
1084                 new_branch_info->name = "HEAD";
1085                 new_branch_info->commit = old_branch_info.commit;
1086                 if (!new_branch_info->commit)
1087                         die(_("You are on a branch yet to be born"));
1088                 parse_commit_or_die(new_branch_info->commit);
1089
1090                 if (opts->only_merge_on_switching_branches)
1091                         do_merge = 0;
1092         }
1093
1094         if (do_merge) {
1095                 ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error);
1096                 if (ret) {
1097                         free(path_to_free);
1098                         return ret;
1099                 }
1100         }
1101
1102         if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit)
1103                 orphaned_commit_warning(old_branch_info.commit, new_branch_info->commit);
1104
1105         update_refs_for_switch(opts, &old_branch_info, new_branch_info);
1106
1107         ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
1108         free(path_to_free);
1109         return ret || writeout_error;
1110 }
1111
1112 static int git_checkout_config(const char *var, const char *value, void *cb)
1113 {
1114         struct checkout_opts *opts = cb;
1115
1116         if (!strcmp(var, "diff.ignoresubmodules")) {
1117                 handle_ignore_submodules_arg(&opts->diff_options, value);
1118                 return 0;
1119         }
1120         if (!strcmp(var, "checkout.guess")) {
1121                 opts->dwim_new_local_branch = git_config_bool(var, value);
1122                 return 0;
1123         }
1124
1125         if (starts_with(var, "submodule."))
1126                 return git_default_submodule_config(var, value, NULL);
1127
1128         return git_xmerge_config(var, value, NULL);
1129 }
1130
1131 static void setup_new_branch_info_and_source_tree(
1132         struct branch_info *new_branch_info,
1133         struct checkout_opts *opts,
1134         struct object_id *rev,
1135         const char *arg)
1136 {
1137         struct tree **source_tree = &opts->source_tree;
1138         struct object_id branch_rev;
1139
1140         new_branch_info->name = arg;
1141         setup_branch_path(new_branch_info);
1142
1143         if (!check_refname_format(new_branch_info->path, 0) &&
1144             !read_ref(new_branch_info->path, &branch_rev))
1145                 oidcpy(rev, &branch_rev);
1146         else {
1147                 free((char *)new_branch_info->path);
1148                 new_branch_info->path = NULL; /* not an existing branch */
1149         }
1150
1151         new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
1152         if (!new_branch_info->commit) {
1153                 /* not a commit */
1154                 *source_tree = parse_tree_indirect(rev);
1155         } else {
1156                 parse_commit_or_die(new_branch_info->commit);
1157                 *source_tree = get_commit_tree(new_branch_info->commit);
1158         }
1159 }
1160
1161 static const char *parse_remote_branch(const char *arg,
1162                                        struct object_id *rev,
1163                                        int could_be_checkout_paths)
1164 {
1165         int num_matches = 0;
1166         const char *remote = unique_tracking_name(arg, rev, &num_matches);
1167
1168         if (remote && could_be_checkout_paths) {
1169                 die(_("'%s' could be both a local file and a tracking branch.\n"
1170                         "Please use -- (and optionally --no-guess) to disambiguate"),
1171                     arg);
1172         }
1173
1174         if (!remote && num_matches > 1) {
1175             if (advice_checkout_ambiguous_remote_branch_name) {
1176                     advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
1177                              "you can do so by fully qualifying the name with the --track option:\n"
1178                              "\n"
1179                              "    git checkout --track origin/<name>\n"
1180                              "\n"
1181                              "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
1182                              "one remote, e.g. the 'origin' remote, consider setting\n"
1183                              "checkout.defaultRemote=origin in your config."));
1184             }
1185
1186             die(_("'%s' matched multiple (%d) remote tracking branches"),
1187                 arg, num_matches);
1188         }
1189
1190         return remote;
1191 }
1192
1193 static int parse_branchname_arg(int argc, const char **argv,
1194                                 int dwim_new_local_branch_ok,
1195                                 struct branch_info *new_branch_info,
1196                                 struct checkout_opts *opts,
1197                                 struct object_id *rev)
1198 {
1199         const char **new_branch = &opts->new_branch;
1200         int argcount = 0;
1201         const char *arg;
1202         int dash_dash_pos;
1203         int has_dash_dash = 0;
1204         int i;
1205
1206         /*
1207          * case 1: git checkout <ref> -- [<paths>]
1208          *
1209          *   <ref> must be a valid tree, everything after the '--' must be
1210          *   a path.
1211          *
1212          * case 2: git checkout -- [<paths>]
1213          *
1214          *   everything after the '--' must be paths.
1215          *
1216          * case 3: git checkout <something> [--]
1217          *
1218          *   (a) If <something> is a commit, that is to
1219          *       switch to the branch or detach HEAD at it.  As a special case,
1220          *       if <something> is A...B (missing A or B means HEAD but you can
1221          *       omit at most one side), and if there is a unique merge base
1222          *       between A and B, A...B names that merge base.
1223          *
1224          *   (b) If <something> is _not_ a commit, either "--" is present
1225          *       or <something> is not a path, no -t or -b was given, and
1226          *       and there is a tracking branch whose name is <something>
1227          *       in one and only one remote (or if the branch exists on the
1228          *       remote named in checkout.defaultRemote), then this is a
1229          *       short-hand to fork local <something> from that
1230          *       remote-tracking branch.
1231          *
1232          *   (c) Otherwise, if "--" is present, treat it like case (1).
1233          *
1234          *   (d) Otherwise :
1235          *       - if it's a reference, treat it like case (1)
1236          *       - else if it's a path, treat it like case (2)
1237          *       - else: fail.
1238          *
1239          * case 4: git checkout <something> <paths>
1240          *
1241          *   The first argument must not be ambiguous.
1242          *   - If it's *only* a reference, treat it like case (1).
1243          *   - If it's only a path, treat it like case (2).
1244          *   - else: fail.
1245          *
1246          */
1247         if (!argc)
1248                 return 0;
1249
1250         if (!opts->accept_pathspec) {
1251                 if (argc > 1)
1252                         die(_("only one reference expected"));
1253                 has_dash_dash = 1; /* helps disambiguate */
1254         }
1255
1256         arg = argv[0];
1257         dash_dash_pos = -1;
1258         for (i = 0; i < argc; i++) {
1259                 if (opts->accept_pathspec && !strcmp(argv[i], "--")) {
1260                         dash_dash_pos = i;
1261                         break;
1262                 }
1263         }
1264         if (dash_dash_pos == 0)
1265                 return 1; /* case (2) */
1266         else if (dash_dash_pos == 1)
1267                 has_dash_dash = 1; /* case (3) or (1) */
1268         else if (dash_dash_pos >= 2)
1269                 die(_("only one reference expected, %d given."), dash_dash_pos);
1270         opts->count_checkout_paths = !opts->quiet && !has_dash_dash;
1271
1272         if (!strcmp(arg, "-"))
1273                 arg = "@{-1}";
1274
1275         if (get_oid_mb(arg, rev)) {
1276                 /*
1277                  * Either case (3) or (4), with <something> not being
1278                  * a commit, or an attempt to use case (1) with an
1279                  * invalid ref.
1280                  *
1281                  * It's likely an error, but we need to find out if
1282                  * we should auto-create the branch, case (3).(b).
1283                  */
1284                 int recover_with_dwim = dwim_new_local_branch_ok;
1285
1286                 int could_be_checkout_paths = !has_dash_dash &&
1287                         check_filename(opts->prefix, arg);
1288
1289                 if (!has_dash_dash && !no_wildcard(arg))
1290                         recover_with_dwim = 0;
1291
1292                 /*
1293                  * Accept "git checkout foo", "git checkout foo --"
1294                  * and "git switch foo" as candidates for dwim.
1295                  */
1296                 if (!(argc == 1 && !has_dash_dash) &&
1297                     !(argc == 2 && has_dash_dash) &&
1298                     opts->accept_pathspec)
1299                         recover_with_dwim = 0;
1300
1301                 if (recover_with_dwim) {
1302                         const char *remote = parse_remote_branch(arg, rev,
1303                                                                  could_be_checkout_paths);
1304                         if (remote) {
1305                                 *new_branch = arg;
1306                                 arg = remote;
1307                                 /* DWIMmed to create local branch, case (3).(b) */
1308                         } else {
1309                                 recover_with_dwim = 0;
1310                         }
1311                 }
1312
1313                 if (!recover_with_dwim) {
1314                         if (has_dash_dash)
1315                                 die(_("invalid reference: %s"), arg);
1316                         return argcount;
1317                 }
1318         }
1319
1320         /* we can't end up being in (2) anymore, eat the argument */
1321         argcount++;
1322         argv++;
1323         argc--;
1324
1325         setup_new_branch_info_and_source_tree(new_branch_info, opts, rev, arg);
1326
1327         if (!opts->source_tree)                   /* case (1): want a tree */
1328                 die(_("reference is not a tree: %s"), arg);
1329
1330         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1331                 /*
1332                  * Do not complain the most common case
1333                  *      git checkout branch
1334                  * even if there happen to be a file called 'branch';
1335                  * it would be extremely annoying.
1336                  */
1337                 if (argc)
1338                         verify_non_filename(opts->prefix, arg);
1339         } else if (opts->accept_pathspec) {
1340                 argcount++;
1341                 argv++;
1342                 argc--;
1343         }
1344
1345         return argcount;
1346 }
1347
1348 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1349 {
1350         int status;
1351         struct strbuf branch_ref = STRBUF_INIT;
1352
1353         trace2_cmd_mode("unborn");
1354
1355         if (!opts->new_branch)
1356                 die(_("You are on a branch yet to be born"));
1357         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1358         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1359         strbuf_release(&branch_ref);
1360         if (!opts->quiet)
1361                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1362                         opts->new_branch);
1363         return status;
1364 }
1365
1366 static void die_expecting_a_branch(const struct branch_info *branch_info)
1367 {
1368         struct object_id oid;
1369         char *to_free;
1370
1371         if (dwim_ref(branch_info->name, strlen(branch_info->name), &oid, &to_free, 0) == 1) {
1372                 const char *ref = to_free;
1373
1374                 if (skip_prefix(ref, "refs/tags/", &ref))
1375                         die(_("a branch is expected, got tag '%s'"), ref);
1376                 if (skip_prefix(ref, "refs/remotes/", &ref))
1377                         die(_("a branch is expected, got remote branch '%s'"), ref);
1378                 die(_("a branch is expected, got '%s'"), ref);
1379         }
1380         if (branch_info->commit)
1381                 die(_("a branch is expected, got commit '%s'"), branch_info->name);
1382         /*
1383          * This case should never happen because we already die() on
1384          * non-commit, but just in case.
1385          */
1386         die(_("a branch is expected, got '%s'"), branch_info->name);
1387 }
1388
1389 static void die_if_some_operation_in_progress(void)
1390 {
1391         struct wt_status_state state;
1392
1393         memset(&state, 0, sizeof(state));
1394         wt_status_get_state(the_repository, &state, 0);
1395
1396         if (state.merge_in_progress)
1397                 die(_("cannot switch branch while merging\n"
1398                       "Consider \"git merge --quit\" "
1399                       "or \"git worktree add\"."));
1400         if (state.am_in_progress)
1401                 die(_("cannot switch branch in the middle of an am session\n"
1402                       "Consider \"git am --quit\" "
1403                       "or \"git worktree add\"."));
1404         if (state.rebase_interactive_in_progress || state.rebase_in_progress)
1405                 die(_("cannot switch branch while rebasing\n"
1406                       "Consider \"git rebase --quit\" "
1407                       "or \"git worktree add\"."));
1408         if (state.cherry_pick_in_progress)
1409                 die(_("cannot switch branch while cherry-picking\n"
1410                       "Consider \"git cherry-pick --quit\" "
1411                       "or \"git worktree add\"."));
1412         if (state.revert_in_progress)
1413                 die(_("cannot switch branch while reverting\n"
1414                       "Consider \"git revert --quit\" "
1415                       "or \"git worktree add\"."));
1416         if (state.bisect_in_progress)
1417                 warning(_("you are switching branch while bisecting"));
1418 }
1419
1420 static int checkout_branch(struct checkout_opts *opts,
1421                            struct branch_info *new_branch_info)
1422 {
1423         if (opts->pathspec.nr)
1424                 die(_("paths cannot be used with switching branches"));
1425
1426         if (opts->patch_mode)
1427                 die(_("'%s' cannot be used with switching branches"),
1428                     "--patch");
1429
1430         if (opts->overlay_mode != -1)
1431                 die(_("'%s' cannot be used with switching branches"),
1432                     "--[no]-overlay");
1433
1434         if (opts->writeout_stage)
1435                 die(_("'%s' cannot be used with switching branches"),
1436                     "--ours/--theirs");
1437
1438         if (opts->force && opts->merge)
1439                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1440
1441         if (opts->discard_changes && opts->merge)
1442                 die(_("'%s' cannot be used with '%s'"), "--discard-changes", "--merge");
1443
1444         if (opts->force_detach && opts->new_branch)
1445                 die(_("'%s' cannot be used with '%s'"),
1446                     "--detach", "-b/-B/--orphan");
1447
1448         if (opts->new_orphan_branch) {
1449                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1450                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1451                 if (opts->orphan_from_empty_tree && new_branch_info->name)
1452                         die(_("'%s' cannot take <start-point>"), "--orphan");
1453         } else if (opts->force_detach) {
1454                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1455                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1456         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1457                 opts->track = git_branch_track;
1458
1459         if (new_branch_info->name && !new_branch_info->commit)
1460                 die(_("Cannot switch branch to a non-commit '%s'"),
1461                     new_branch_info->name);
1462
1463         if (!opts->switch_branch_doing_nothing_is_ok &&
1464             !new_branch_info->name &&
1465             !opts->new_branch &&
1466             !opts->force_detach)
1467                 die(_("missing branch or commit argument"));
1468
1469         if (!opts->implicit_detach &&
1470             !opts->force_detach &&
1471             !opts->new_branch &&
1472             !opts->new_branch_force &&
1473             new_branch_info->name &&
1474             !new_branch_info->path)
1475                 die_expecting_a_branch(new_branch_info);
1476
1477         if (!opts->can_switch_when_in_progress)
1478                 die_if_some_operation_in_progress();
1479
1480         if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
1481             !opts->ignore_other_worktrees) {
1482                 int flag;
1483                 char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
1484                 if (head_ref &&
1485                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path)))
1486                         die_if_checked_out(new_branch_info->path, 1);
1487                 free(head_ref);
1488         }
1489
1490         if (!new_branch_info->commit && opts->new_branch) {
1491                 struct object_id rev;
1492                 int flag;
1493
1494                 if (!read_ref_full("HEAD", 0, &rev, &flag) &&
1495                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1496                         return switch_unborn_to_new_branch(opts);
1497         }
1498         return switch_branches(opts, new_branch_info);
1499 }
1500
1501 static struct option *add_common_options(struct checkout_opts *opts,
1502                                          struct option *prevopts)
1503 {
1504         struct option options[] = {
1505                 OPT__QUIET(&opts->quiet, N_("suppress progress reporting")),
1506                 OPT_CALLBACK_F(0, "recurse-submodules", NULL,
1507                             "checkout", "control recursive updating of submodules",
1508                             PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater),
1509                 OPT_BOOL(0, "progress", &opts->show_progress, N_("force progress reporting")),
1510                 OPT_BOOL('m', "merge", &opts->merge, N_("perform a 3-way merge with the new branch")),
1511                 OPT_STRING(0, "conflict", &opts->conflict_style, N_("style"),
1512                            N_("conflict style (merge or diff3)")),
1513                 OPT_END()
1514         };
1515         struct option *newopts = parse_options_concat(prevopts, options);
1516         free(prevopts);
1517         return newopts;
1518 }
1519
1520 static struct option *add_common_switch_branch_options(
1521         struct checkout_opts *opts, struct option *prevopts)
1522 {
1523         struct option options[] = {
1524                 OPT_BOOL('d', "detach", &opts->force_detach, N_("detach HEAD at named commit")),
1525                 OPT_SET_INT('t', "track",  &opts->track, N_("set upstream info for new branch"),
1526                         BRANCH_TRACK_EXPLICIT),
1527                 OPT__FORCE(&opts->force, N_("force checkout (throw away local modifications)"),
1528                            PARSE_OPT_NOCOMPLETE),
1529                 OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1530                 OPT_BOOL_F(0, "overwrite-ignore", &opts->overwrite_ignore,
1531                            N_("update ignored files (default)"),
1532                            PARSE_OPT_NOCOMPLETE),
1533                 OPT_BOOL(0, "ignore-other-worktrees", &opts->ignore_other_worktrees,
1534                          N_("do not check if another worktree is holding the given ref")),
1535                 OPT_END()
1536         };
1537         struct option *newopts = parse_options_concat(prevopts, options);
1538         free(prevopts);
1539         return newopts;
1540 }
1541
1542 static struct option *add_checkout_path_options(struct checkout_opts *opts,
1543                                                 struct option *prevopts)
1544 {
1545         struct option options[] = {
1546                 OPT_SET_INT_F('2', "ours", &opts->writeout_stage,
1547                               N_("checkout our version for unmerged files"),
1548                               2, PARSE_OPT_NONEG),
1549                 OPT_SET_INT_F('3', "theirs", &opts->writeout_stage,
1550                               N_("checkout their version for unmerged files"),
1551                               3, PARSE_OPT_NONEG),
1552                 OPT_BOOL('p', "patch", &opts->patch_mode, N_("select hunks interactively")),
1553                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts->ignore_skipworktree,
1554                          N_("do not limit pathspecs to sparse entries only")),
1555                 OPT_PATHSPEC_FROM_FILE(&opts->pathspec_from_file),
1556                 OPT_PATHSPEC_FILE_NUL(&opts->pathspec_file_nul),
1557                 OPT_END()
1558         };
1559         struct option *newopts = parse_options_concat(prevopts, options);
1560         free(prevopts);
1561         return newopts;
1562 }
1563
1564 /* create-branch option (either b or c) */
1565 static char cb_option = 'b';
1566
1567 static int checkout_main(int argc, const char **argv, const char *prefix,
1568                          struct checkout_opts *opts, struct option *options,
1569                          const char * const usagestr[])
1570 {
1571         struct branch_info new_branch_info;
1572         int parseopt_flags = 0;
1573
1574         memset(&new_branch_info, 0, sizeof(new_branch_info));
1575         opts->overwrite_ignore = 1;
1576         opts->prefix = prefix;
1577         opts->show_progress = -1;
1578
1579         git_config(git_checkout_config, opts);
1580
1581         opts->track = BRANCH_TRACK_UNSPECIFIED;
1582
1583         if (!opts->accept_pathspec && !opts->accept_ref)
1584                 BUG("make up your mind, you need to take _something_");
1585         if (opts->accept_pathspec && opts->accept_ref)
1586                 parseopt_flags = PARSE_OPT_KEEP_DASHDASH;
1587
1588         argc = parse_options(argc, argv, prefix, options,
1589                              usagestr, parseopt_flags);
1590
1591         if (opts->show_progress < 0) {
1592                 if (opts->quiet)
1593                         opts->show_progress = 0;
1594                 else
1595                         opts->show_progress = isatty(2);
1596         }
1597
1598         if (opts->conflict_style) {
1599                 opts->merge = 1; /* implied */
1600                 git_xmerge_config("merge.conflictstyle", opts->conflict_style, NULL);
1601         }
1602         if (opts->force) {
1603                 opts->discard_changes = 1;
1604                 opts->ignore_unmerged_opt = "--force";
1605                 opts->ignore_unmerged = 1;
1606         }
1607
1608         if ((!!opts->new_branch + !!opts->new_branch_force + !!opts->new_orphan_branch) > 1)
1609                 die(_("-%c, -%c and --orphan are mutually exclusive"),
1610                                 cb_option, toupper(cb_option));
1611
1612         if (opts->overlay_mode == 1 && opts->patch_mode)
1613                 die(_("-p and --overlay are mutually exclusive"));
1614
1615         if (opts->checkout_index >= 0 || opts->checkout_worktree >= 0) {
1616                 if (opts->checkout_index < 0)
1617                         opts->checkout_index = 0;
1618                 if (opts->checkout_worktree < 0)
1619                         opts->checkout_worktree = 0;
1620         } else {
1621                 if (opts->checkout_index < 0)
1622                         opts->checkout_index = -opts->checkout_index - 1;
1623                 if (opts->checkout_worktree < 0)
1624                         opts->checkout_worktree = -opts->checkout_worktree - 1;
1625         }
1626         if (opts->checkout_index < 0 || opts->checkout_worktree < 0)
1627                 BUG("these flags should be non-negative by now");
1628         /*
1629          * convenient shortcut: "git restore --staged [--worktree]" equals
1630          * "git restore --staged [--worktree] --source HEAD"
1631          */
1632         if (!opts->from_treeish && opts->checkout_index)
1633                 opts->from_treeish = "HEAD";
1634
1635         /*
1636          * From here on, new_branch will contain the branch to be checked out,
1637          * and new_branch_force and new_orphan_branch will tell us which one of
1638          * -b/-B/-c/-C/--orphan is being used.
1639          */
1640         if (opts->new_branch_force)
1641                 opts->new_branch = opts->new_branch_force;
1642
1643         if (opts->new_orphan_branch)
1644                 opts->new_branch = opts->new_orphan_branch;
1645
1646         /* --track without -c/-C/-b/-B/--orphan should DWIM */
1647         if (opts->track != BRANCH_TRACK_UNSPECIFIED && !opts->new_branch) {
1648                 const char *argv0 = argv[0];
1649                 if (!argc || !strcmp(argv0, "--"))
1650                         die(_("--track needs a branch name"));
1651                 skip_prefix(argv0, "refs/", &argv0);
1652                 skip_prefix(argv0, "remotes/", &argv0);
1653                 argv0 = strchr(argv0, '/');
1654                 if (!argv0 || !argv0[1])
1655                         die(_("missing branch name; try -%c"), cb_option);
1656                 opts->new_branch = argv0 + 1;
1657         }
1658
1659         /*
1660          * Extract branch name from command line arguments, so
1661          * all that is left is pathspecs.
1662          *
1663          * Handle
1664          *
1665          *  1) git checkout <tree> -- [<paths>]
1666          *  2) git checkout -- [<paths>]
1667          *  3) git checkout <something> [<paths>]
1668          *
1669          * including "last branch" syntax and DWIM-ery for names of
1670          * remote branches, erroring out for invalid or ambiguous cases.
1671          */
1672         if (argc && opts->accept_ref) {
1673                 struct object_id rev;
1674                 int dwim_ok =
1675                         !opts->patch_mode &&
1676                         opts->dwim_new_local_branch &&
1677                         opts->track == BRANCH_TRACK_UNSPECIFIED &&
1678                         !opts->new_branch;
1679                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1680                                              &new_branch_info, opts, &rev);
1681                 argv += n;
1682                 argc -= n;
1683         } else if (!opts->accept_ref && opts->from_treeish) {
1684                 struct object_id rev;
1685
1686                 if (get_oid_mb(opts->from_treeish, &rev))
1687                         die(_("could not resolve %s"), opts->from_treeish);
1688
1689                 setup_new_branch_info_and_source_tree(&new_branch_info,
1690                                                       opts, &rev,
1691                                                       opts->from_treeish);
1692
1693                 if (!opts->source_tree)
1694                         die(_("reference is not a tree: %s"), opts->from_treeish);
1695         }
1696
1697         if (argc) {
1698                 parse_pathspec(&opts->pathspec, 0,
1699                                opts->patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1700                                prefix, argv);
1701
1702                 if (!opts->pathspec.nr)
1703                         die(_("invalid path specification"));
1704
1705                 /*
1706                  * Try to give more helpful suggestion.
1707                  * new_branch && argc > 1 will be caught later.
1708                  */
1709                 if (opts->new_branch && argc == 1 && !new_branch_info.commit)
1710                         die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1711                                 argv[0], opts->new_branch);
1712
1713                 if (opts->force_detach)
1714                         die(_("git checkout: --detach does not take a path argument '%s'"),
1715                             argv[0]);
1716         }
1717
1718         if (opts->pathspec_from_file) {
1719                 if (opts->pathspec.nr)
1720                         die(_("--pathspec-from-file is incompatible with pathspec arguments"));
1721
1722                 if (opts->force_detach)
1723                         die(_("--pathspec-from-file is incompatible with --detach"));
1724
1725                 if (opts->patch_mode)
1726                         die(_("--pathspec-from-file is incompatible with --patch"));
1727
1728                 parse_pathspec_file(&opts->pathspec, 0,
1729                                     0,
1730                                     prefix, opts->pathspec_from_file, opts->pathspec_file_nul);
1731         } else if (opts->pathspec_file_nul) {
1732                 die(_("--pathspec-file-nul requires --pathspec-from-file"));
1733         }
1734
1735         opts->pathspec.recursive = 1;
1736
1737         if (opts->pathspec.nr) {
1738                 if (1 < !!opts->writeout_stage + !!opts->force + !!opts->merge)
1739                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1740                               "checking out of the index."));
1741         } else {
1742                 if (opts->accept_pathspec && !opts->empty_pathspec_ok &&
1743                     !opts->patch_mode)  /* patch mode is special */
1744                         die(_("you must specify path(s) to restore"));
1745         }
1746
1747         if (opts->new_branch) {
1748                 struct strbuf buf = STRBUF_INIT;
1749
1750                 if (opts->new_branch_force)
1751                         opts->branch_exists = validate_branchname(opts->new_branch, &buf);
1752                 else
1753                         opts->branch_exists =
1754                                 validate_new_branchname(opts->new_branch, &buf, 0);
1755                 strbuf_release(&buf);
1756         }
1757
1758         UNLEAK(opts);
1759         if (opts->patch_mode || opts->pathspec.nr)
1760                 return checkout_paths(opts, &new_branch_info);
1761         else
1762                 return checkout_branch(opts, &new_branch_info);
1763 }
1764
1765 int cmd_checkout(int argc, const char **argv, const char *prefix)
1766 {
1767         struct checkout_opts opts;
1768         struct option *options;
1769         struct option checkout_options[] = {
1770                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1771                            N_("create and checkout a new branch")),
1772                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1773                            N_("create/reset and checkout a branch")),
1774                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1775                 OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
1776                          N_("second guess 'git checkout <no-such-branch>' (default)")),
1777                 OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode (default)")),
1778                 OPT_END()
1779         };
1780         int ret;
1781
1782         memset(&opts, 0, sizeof(opts));
1783         opts.dwim_new_local_branch = 1;
1784         opts.switch_branch_doing_nothing_is_ok = 1;
1785         opts.only_merge_on_switching_branches = 0;
1786         opts.accept_ref = 1;
1787         opts.accept_pathspec = 1;
1788         opts.implicit_detach = 1;
1789         opts.can_switch_when_in_progress = 1;
1790         opts.orphan_from_empty_tree = 0;
1791         opts.empty_pathspec_ok = 1;
1792         opts.overlay_mode = -1;
1793         opts.checkout_index = -2;    /* default on */
1794         opts.checkout_worktree = -2; /* default on */
1795
1796         if (argc == 3 && !strcmp(argv[1], "-b")) {
1797                 /*
1798                  * User ran 'git checkout -b <branch>' and expects
1799                  * the same behavior as 'git switch -c <branch>'.
1800                  */
1801                 opts.switch_branch_doing_nothing_is_ok = 0;
1802                 opts.only_merge_on_switching_branches = 1;
1803         }
1804
1805         options = parse_options_dup(checkout_options);
1806         options = add_common_options(&opts, options);
1807         options = add_common_switch_branch_options(&opts, options);
1808         options = add_checkout_path_options(&opts, options);
1809
1810         ret = checkout_main(argc, argv, prefix, &opts,
1811                             options, checkout_usage);
1812         FREE_AND_NULL(options);
1813         return ret;
1814 }
1815
1816 int cmd_switch(int argc, const char **argv, const char *prefix)
1817 {
1818         struct checkout_opts opts;
1819         struct option *options = NULL;
1820         struct option switch_options[] = {
1821                 OPT_STRING('c', "create", &opts.new_branch, N_("branch"),
1822                            N_("create and switch to a new branch")),
1823                 OPT_STRING('C', "force-create", &opts.new_branch_force, N_("branch"),
1824                            N_("create/reset and switch to a branch")),
1825                 OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
1826                          N_("second guess 'git switch <no-such-branch>'")),
1827                 OPT_BOOL(0, "discard-changes", &opts.discard_changes,
1828                          N_("throw away local modifications")),
1829                 OPT_END()
1830         };
1831         int ret;
1832
1833         memset(&opts, 0, sizeof(opts));
1834         opts.dwim_new_local_branch = 1;
1835         opts.accept_ref = 1;
1836         opts.accept_pathspec = 0;
1837         opts.switch_branch_doing_nothing_is_ok = 0;
1838         opts.only_merge_on_switching_branches = 1;
1839         opts.implicit_detach = 0;
1840         opts.can_switch_when_in_progress = 0;
1841         opts.orphan_from_empty_tree = 1;
1842         opts.overlay_mode = -1;
1843
1844         options = parse_options_dup(switch_options);
1845         options = add_common_options(&opts, options);
1846         options = add_common_switch_branch_options(&opts, options);
1847
1848         cb_option = 'c';
1849
1850         ret = checkout_main(argc, argv, prefix, &opts,
1851                             options, switch_branch_usage);
1852         FREE_AND_NULL(options);
1853         return ret;
1854 }
1855
1856 int cmd_restore(int argc, const char **argv, const char *prefix)
1857 {
1858         struct checkout_opts opts;
1859         struct option *options;
1860         struct option restore_options[] = {
1861                 OPT_STRING('s', "source", &opts.from_treeish, "<tree-ish>",
1862                            N_("which tree-ish to checkout from")),
1863                 OPT_BOOL('S', "staged", &opts.checkout_index,
1864                            N_("restore the index")),
1865                 OPT_BOOL('W', "worktree", &opts.checkout_worktree,
1866                            N_("restore the working tree (default)")),
1867                 OPT_BOOL(0, "ignore-unmerged", &opts.ignore_unmerged,
1868                          N_("ignore unmerged entries")),
1869                 OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode")),
1870                 OPT_END()
1871         };
1872         int ret;
1873
1874         memset(&opts, 0, sizeof(opts));
1875         opts.accept_ref = 0;
1876         opts.accept_pathspec = 1;
1877         opts.empty_pathspec_ok = 0;
1878         opts.overlay_mode = 0;
1879         opts.checkout_index = -1;    /* default off */
1880         opts.checkout_worktree = -2; /* default on */
1881         opts.ignore_unmerged_opt = "--ignore-unmerged";
1882
1883         options = parse_options_dup(restore_options);
1884         options = add_common_options(&opts, options);
1885         options = add_checkout_path_options(&opts, options);
1886
1887         ret = checkout_main(argc, argv, prefix, &opts,
1888                             options, restore_usage);
1889         FREE_AND_NULL(options);
1890         return ret;
1891 }