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 int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
  25
  26 static const char * const checkout_usage[] = {
  27         N_("git checkout [<options>] <branch>"),
  28         N_("git checkout [<options>] [<branch>] -- <file>..."),
  29         NULL,
  30 };
  31
  32 static int option_parse_recurse_submodules(const struct option *opt,
  33                                            const char *arg, int unset)
  34 {
  35         if (unset) {
  36                 recurse_submodules = RECURSE_SUBMODULES_OFF;
  37                 return 0;
  38         }
  39         if (arg)
  40                 recurse_submodules =
  41                         parse_update_recurse_submodules_arg(opt->long_name,
  42                                                             arg);
  43         else
  44                 recurse_submodules = RECURSE_SUBMODULES_ON;
  45
  46         return 0;
  47 }
  48
  49 struct checkout_opts {
  50         int patch_mode;
  51         int quiet;
  52         int merge;
  53         int force;
  54         int force_detach;
  55         int writeout_stage;
  56         int overwrite_ignore;
  57         int ignore_skipworktree;
  58         int ignore_other_worktrees;
  59         int show_progress;
  60
  61         const char *new_branch;
  62         const char *new_branch_force;
  63         const char *new_orphan_branch;
  64         int new_branch_log;
  65         enum branch_track track;
  66         struct diff_options diff_options;
  67
  68         int branch_exists;
  69         const char *prefix;
  70         struct pathspec pathspec;
  71         struct tree *source_tree;
  72 };
  73
  74 static int post_checkout_hook(struct commit *old, struct commit *new,
  75                               int changed)
  76 {
  77         return run_hook_le(NULL, "post-checkout",
  78                            oid_to_hex(old ? &old->object.oid : &null_oid),
  79                            oid_to_hex(new ? &new->object.oid : &null_oid),
  80                            changed ? "1" : "0", NULL);
  81         /* "new" can be NULL when checking out from the index before
  82            a commit exists. */
  83
  84 }
  85
  86 static int update_some(const unsigned char *sha1, struct strbuf *base,
  87                 const char *pathname, unsigned mode, int stage, void *context)
  88 {
  89         int len;
  90         struct cache_entry *ce;
  91         int pos;
  92
  93         if (S_ISDIR(mode))
  94                 return READ_TREE_RECURSIVE;
  95
  96         len = base->len + strlen(pathname);
  97         ce = xcalloc(1, cache_entry_size(len));
  98         hashcpy(ce->oid.hash, sha1);
  99         memcpy(ce->name, base->buf, base->len);
 100         memcpy(ce->name + base->len, pathname, len - base->len);
 101         ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
 102         ce->ce_namelen = len;
 103         ce->ce_mode = create_ce_mode(mode);
 104
 105         /*
 106          * If the entry is the same as the current index, we can leave the old
 107          * entry in place. Whether it is UPTODATE or not, checkout_entry will
 108          * do the right thing.
 109          */
 110         pos = cache_name_pos(ce->name, ce->ce_namelen);
 111         if (pos >= 0) {
 112                 struct cache_entry *old = active_cache[pos];
 113                 if (ce->ce_mode == old->ce_mode &&
 114                     !oidcmp(&ce->oid, &old->oid)) {
 115                         old->ce_flags |= CE_UPDATE;
 116                         free(ce);
 117                         return 0;
 118                 }
 119         }
 120
 121         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 122         return 0;
 123 }
 124
 125 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
 126 {
 127         read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
 128
 129         /* update the index with the given tree's info
 130          * for all args, expanding wildcards, and exit
 131          * with any non-zero return code.
 132          */
 133         return 0;
 134 }
 135
 136 static int skip_same_name(const struct cache_entry *ce, int pos)
 137 {
 138         while (++pos < active_nr &&
 139                !strcmp(active_cache[pos]->name, ce->name))
 140                 ; /* skip */
 141         return pos;
 142 }
 143
 144 static int check_stage(int stage, const struct cache_entry *ce, int pos)
 145 {
 146         while (pos < active_nr &&
 147                !strcmp(active_cache[pos]->name, ce->name)) {
 148                 if (ce_stage(active_cache[pos]) == stage)
 149                         return 0;
 150                 pos++;
 151         }
 152         if (stage == 2)
 153                 return error(_("path '%s' does not have our version"), ce->name);
 154         else
 155                 return error(_("path '%s' does not have their version"), ce->name);
 156 }
 157
 158 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 159 {
 160         unsigned seen = 0;
 161         const char *name = ce->name;
 162
 163         while (pos < active_nr) {
 164                 ce = active_cache[pos];
 165                 if (strcmp(name, ce->name))
 166                         break;
 167                 seen |= (1 << ce_stage(ce));
 168                 pos++;
 169         }
 170         if ((stages & seen) != stages)
 171                 return error(_("path '%s' does not have all necessary versions"),
 172                              name);
 173         return 0;
 174 }
 175
 176 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 177                           const struct checkout *state)
 178 {
 179         while (pos < active_nr &&
 180                !strcmp(active_cache[pos]->name, ce->name)) {
 181                 if (ce_stage(active_cache[pos]) == stage)
 182                         return checkout_entry(active_cache[pos], state, NULL);
 183                 pos++;
 184         }
 185         if (stage == 2)
 186                 return error(_("path '%s' does not have our version"), ce->name);
 187         else
 188                 return error(_("path '%s' does not have their version"), ce->name);
 189 }
 190
 191 static int checkout_merged(int pos, const struct checkout *state)
 192 {
 193         struct cache_entry *ce = active_cache[pos];
 194         const char *path = ce->name;
 195         mmfile_t ancestor, ours, theirs;
 196         int status;
 197         struct object_id oid;
 198         mmbuffer_t result_buf;
 199         struct object_id threeway[3];
 200         unsigned mode = 0;
 201
 202         memset(threeway, 0, sizeof(threeway));
 203         while (pos < active_nr) {
 204                 int stage;
 205                 stage = ce_stage(ce);
 206                 if (!stage || strcmp(path, ce->name))
 207                         break;
 208                 oidcpy(&threeway[stage - 1], &ce->oid);
 209                 if (stage == 2)
 210                         mode = create_ce_mode(ce->ce_mode);
 211                 pos++;
 212                 ce = active_cache[pos];
 213         }
 214         if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 215                 return error(_("path '%s' does not have necessary versions"), path);
 216
 217         read_mmblob(&ancestor, &threeway[0]);
 218         read_mmblob(&ours, &threeway[1]);
 219         read_mmblob(&theirs, &threeway[2]);
 220
 221         /*
 222          * NEEDSWORK: re-create conflicts from merges with
 223          * merge.renormalize set, too
 224          */
 225         status = ll_merge(&result_buf, path, &ancestor, "base",
 226                           &ours, "ours", &theirs, "theirs", NULL);
 227         free(ancestor.ptr);
 228         free(ours.ptr);
 229         free(theirs.ptr);
 230         if (status < 0 || !result_buf.ptr) {
 231                 free(result_buf.ptr);
 232                 return error(_("path '%s': cannot merge"), path);
 233         }
 234
 235         /*
 236          * NEEDSWORK:
 237          * There is absolutely no reason to write this as a blob object
 238          * and create a phony cache entry just to leak.  This hack is
 239          * primarily to get to the write_entry() machinery that massages
 240          * the contents to work-tree format and writes out which only
 241          * allows it for a cache entry.  The code in write_entry() needs
 242          * to be refactored to allow us to feed a <buffer, size, mode>
 243          * instead of a cache entry.  Such a refactoring would help
 244          * merge_recursive as well (it also writes the merge result to the
 245          * object database even when it may contain conflicts).
 246          */
 247         if (write_sha1_file(result_buf.ptr, result_buf.size,
 248                             blob_type, oid.hash))
 249                 die(_("Unable to add merge result for '%s'"), path);
 250         ce = make_cache_entry(mode, oid.hash, path, 2, 0);
 251         if (!ce)
 252                 die(_("make_cache_entry failed for path '%s'"), path);
 253         status = checkout_entry(ce, state, NULL);
 254         return status;
 255 }
 256
 257 static int checkout_paths(const struct checkout_opts *opts,
 258                           const char *revision)
 259 {
 260         int pos;
 261         struct checkout state = CHECKOUT_INIT;
 262         static char *ps_matched;
 263         struct object_id rev;
 264         struct commit *head;
 265         int errs = 0;
 266         struct lock_file *lock_file;
 267
 268         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 269                 die(_("'%s' cannot be used with updating paths"), "--track");
 270
 271         if (opts->new_branch_log)
 272                 die(_("'%s' cannot be used with updating paths"), "-l");
 273
 274         if (opts->force && opts->patch_mode)
 275                 die(_("'%s' cannot be used with updating paths"), "-f");
 276
 277         if (opts->force_detach)
 278                 die(_("'%s' cannot be used with updating paths"), "--detach");
 279
 280         if (opts->merge && opts->patch_mode)
 281                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 282
 283         if (opts->force && opts->merge)
 284                 die(_("'%s' cannot be used with %s"), "-f", "-m");
 285
 286         if (opts->new_branch)
 287                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 288                     opts->new_branch);
 289
 290         if (opts->patch_mode)
 291                 return run_add_interactive(revision, "--patch=checkout",
 292                                            &opts->pathspec);
 293
 294         lock_file = xcalloc(1, sizeof(struct lock_file));
 295
 296         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 297         if (read_cache_preload(&opts->pathspec) < 0)
 298                 return error(_("index file corrupt"));
 299
 300         if (opts->source_tree)
 301                 read_tree_some(opts->source_tree, &opts->pathspec);
 302
 303         ps_matched = xcalloc(opts->pathspec.nr, 1);
 304
 305         /*
 306          * Make sure all pathspecs participated in locating the paths
 307          * to be checked out.
 308          */
 309         for (pos = 0; pos < active_nr; pos++) {
 310                 struct cache_entry *ce = active_cache[pos];
 311                 ce->ce_flags &= ~CE_MATCHED;
 312                 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 313                         continue;
 314                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 315                         /*
 316                          * "git checkout tree-ish -- path", but this entry
 317                          * is in the original index; it will not be checked
 318                          * out to the working tree and it does not matter
 319                          * if pathspec matched this entry.  We will not do
 320                          * anything to this entry at all.
 321                          */
 322                         continue;
 323                 /*
 324                  * Either this entry came from the tree-ish we are
 325                  * checking the paths out of, or we are checking out
 326                  * of the index.
 327                  *
 328                  * If it comes from the tree-ish, we already know it
 329                  * matches the pathspec and could just stamp
 330                  * CE_MATCHED to it from update_some(). But we still
 331                  * need ps_matched and read_tree_recursive (and
 332                  * eventually tree_entry_interesting) cannot fill
 333                  * ps_matched yet. Once it can, we can avoid calling
 334                  * match_pathspec() for _all_ entries when
 335                  * opts->source_tree != NULL.
 336                  */
 337                 if (ce_path_match(ce, &opts->pathspec, ps_matched))
 338                         ce->ce_flags |= CE_MATCHED;
 339         }
 340
 341         if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
 342                 free(ps_matched);
 343                 return 1;
 344         }
 345         free(ps_matched);
 346
 347         /* "checkout -m path" to recreate conflicted state */
 348         if (opts->merge)
 349                 unmerge_marked_index(&the_index);
 350
 351         /* Any unmerged paths? */
 352         for (pos = 0; pos < active_nr; pos++) {
 353                 const struct cache_entry *ce = active_cache[pos];
 354                 if (ce->ce_flags & CE_MATCHED) {
 355                         if (!ce_stage(ce))
 356                                 continue;
 357                         if (opts->force) {
 358                                 warning(_("path '%s' is unmerged"), ce->name);
 359                         } else if (opts->writeout_stage) {
 360                                 errs |= check_stage(opts->writeout_stage, ce, pos);
 361                         } else if (opts->merge) {
 362                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 363                         } else {
 364                                 errs = 1;
 365                                 error(_("path '%s' is unmerged"), ce->name);
 366                         }
 367                         pos = skip_same_name(ce, pos) - 1;
 368                 }
 369         }
 370         if (errs)
 371                 return 1;
 372
 373         /* Now we are committed to check them out */
 374         state.force = 1;
 375         state.refresh_cache = 1;
 376         state.istate = &the_index;
 377         for (pos = 0; pos < active_nr; pos++) {
 378                 struct cache_entry *ce = active_cache[pos];
 379                 if (ce->ce_flags & CE_MATCHED) {
 380                         if (!ce_stage(ce)) {
 381                                 errs |= checkout_entry(ce, &state, NULL);
 382                                 continue;
 383                         }
 384                         if (opts->writeout_stage)
 385                                 errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
 386                         else if (opts->merge)
 387                                 errs |= checkout_merged(pos, &state);
 388                         pos = skip_same_name(ce, pos) - 1;
 389                 }
 390         }
 391
 392         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 393                 die(_("unable to write new index file"));
 394
 395         read_ref_full("HEAD", 0, rev.hash, NULL);
 396         head = lookup_commit_reference_gently(rev.hash, 1);
 397
 398         errs |= post_checkout_hook(head, head, 0);
 399         return errs;
 400 }
 401
 402 static void show_local_changes(struct object *head,
 403                                const struct diff_options *opts)
 404 {
 405         struct rev_info rev;
 406         /* I think we want full paths, even if we're in a subdirectory. */
 407         init_revisions(&rev, NULL);
 408         rev.diffopt.flags = opts->flags;
 409         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 410         diff_setup_done(&rev.diffopt);
 411         add_pending_object(&rev, head, NULL);
 412         run_diff_index(&rev, 0);
 413 }
 414
 415 static void describe_detached_head(const char *msg, struct commit *commit)
 416 {
 417         struct strbuf sb = STRBUF_INIT;
 418         if (!parse_commit(commit))
 419                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 420         fprintf(stderr, "%s %s... %s\n", msg,
 421                 find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
 422         strbuf_release(&sb);
 423 }
 424
 425 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 426                       int worktree, int *writeout_error)
 427 {
 428         struct unpack_trees_options opts;
 429         struct tree_desc tree_desc;
 430
 431         memset(&opts, 0, sizeof(opts));
 432         opts.head_idx = -1;
 433         opts.update = worktree;
 434         opts.skip_unmerged = !worktree;
 435         opts.reset = 1;
 436         opts.merge = 1;
 437         opts.fn = oneway_merge;
 438         opts.verbose_update = o->show_progress;
 439         opts.src_index = &the_index;
 440         opts.dst_index = &the_index;
 441         parse_tree(tree);
 442         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 443         switch (unpack_trees(1, &tree_desc, &opts)) {
 444         case -2:
 445                 *writeout_error = 1;
 446                 /*
 447                  * We return 0 nevertheless, as the index is all right
 448                  * and more importantly we have made best efforts to
 449                  * update paths in the work tree, and we cannot revert
 450                  * them.
 451                  */
 452         case 0:
 453                 return 0;
 454         default:
 455                 return 128;
 456         }
 457 }
 458
 459 struct branch_info {
 460         const char *name; /* The short name used */
 461         const char *path; /* The full name of a real branch */
 462         struct commit *commit; /* The named commit */
 463         /*
 464          * if not null the branch is detached because it's already
 465          * checked out in this checkout
 466          */
 467         char *checkout;
 468 };
 469
 470 static void setup_branch_path(struct branch_info *branch)
 471 {
 472         struct strbuf buf = STRBUF_INIT;
 473
 474         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 475         if (strcmp(buf.buf, branch->name))
 476                 branch->name = xstrdup(buf.buf);
 477         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 478         branch->path = strbuf_detach(&buf, NULL);
 479 }
 480
 481 static int merge_working_tree(const struct checkout_opts *opts,
 482                               struct branch_info *old,
 483                               struct branch_info *new,
 484                               int *writeout_error)
 485 {
 486         int ret;
 487         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 488
 489         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 490         if (read_cache_preload(NULL) < 0)
 491                 return error(_("index file corrupt"));
 492
 493         resolve_undo_clear();
 494         if (opts->force) {
 495                 ret = reset_tree(new->commit->tree, opts, 1, writeout_error);
 496                 if (ret)
 497                         return ret;
 498         } else {
 499                 struct tree_desc trees[2];
 500                 struct tree *tree;
 501                 struct unpack_trees_options topts;
 502
 503                 memset(&topts, 0, sizeof(topts));
 504                 topts.head_idx = -1;
 505                 topts.src_index = &the_index;
 506                 topts.dst_index = &the_index;
 507
 508                 setup_unpack_trees_porcelain(&topts, "checkout");
 509
 510                 refresh_cache(REFRESH_QUIET);
 511
 512                 if (unmerged_cache()) {
 513                         error(_("you need to resolve your current index first"));
 514                         return 1;
 515                 }
 516
 517                 /* 2-way merge to the new branch */
 518                 topts.initial_checkout = is_cache_unborn();
 519                 topts.update = 1;
 520                 topts.merge = 1;
 521                 topts.gently = opts->merge && old->commit;
 522                 topts.verbose_update = opts->show_progress;
 523                 topts.fn = twoway_merge;
 524                 if (opts->overwrite_ignore) {
 525                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 526                         topts.dir->flags |= DIR_SHOW_IGNORED;
 527                         setup_standard_excludes(topts.dir);
 528                 }
 529                 tree = parse_tree_indirect(old->commit ?
 530                                            old->commit->object.oid.hash :
 531                                            EMPTY_TREE_SHA1_BIN);
 532                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 533                 tree = parse_tree_indirect(new->commit->object.oid.hash);
 534                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 535
 536                 ret = unpack_trees(2, trees, &topts);
 537                 if (ret == -1) {
 538                         /*
 539                          * Unpack couldn't do a trivial merge; either
 540                          * give up or do a real merge, depending on
 541                          * whether the merge flag was used.
 542                          */
 543                         struct tree *result;
 544                         struct tree *work;
 545                         struct merge_options o;
 546                         if (!opts->merge)
 547                                 return 1;
 548
 549                         /*
 550                          * Without old->commit, the below is the same as
 551                          * the two-tree unpack we already tried and failed.
 552                          */
 553                         if (!old->commit)
 554                                 return 1;
 555
 556                         /* Do more real merge */
 557
 558                         /*
 559                          * We update the index fully, then write the
 560                          * tree from the index, then merge the new
 561                          * branch with the current tree, with the old
 562                          * branch as the base. Then we reset the index
 563                          * (but not the working tree) to the new
 564                          * branch, leaving the working tree as the
 565                          * merged version, but skipping unmerged
 566                          * entries in the index.
 567                          */
 568
 569                         add_files_to_cache(NULL, NULL, 0);
 570                         /*
 571                          * NEEDSWORK: carrying over local changes
 572                          * when branches have different end-of-line
 573                          * normalization (or clean+smudge rules) is
 574                          * a pain; plumb in an option to set
 575                          * o.renormalize?
 576                          */
 577                         init_merge_options(&o);
 578                         o.verbosity = 0;
 579                         work = write_tree_from_memory(&o);
 580
 581                         ret = reset_tree(new->commit->tree, opts, 1,
 582                                          writeout_error);
 583                         if (ret)
 584                                 return ret;
 585                         o.ancestor = old->name;
 586                         o.branch1 = new->name;
 587                         o.branch2 = "local";
 588                         ret = merge_trees(&o, new->commit->tree, work,
 589                                 old->commit->tree, &result);
 590                         if (ret < 0)
 591                                 exit(128);
 592                         ret = reset_tree(new->commit->tree, opts, 0,
 593                                          writeout_error);
 594                         strbuf_release(&o.obuf);
 595                         if (ret)
 596                                 return ret;
 597                 }
 598         }
 599
 600         if (!active_cache_tree)
 601                 active_cache_tree = cache_tree();
 602
 603         if (!cache_tree_fully_valid(active_cache_tree))
 604                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 605
 606         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 607                 die(_("unable to write new index file"));
 608
 609         if (!opts->force && !opts->quiet)
 610                 show_local_changes(&new->commit->object, &opts->diff_options);
 611
 612         return 0;
 613 }
 614
 615 static void report_tracking(struct branch_info *new)
 616 {
 617         struct strbuf sb = STRBUF_INIT;
 618         struct branch *branch = branch_get(new->name);
 619
 620         if (!format_tracking_info(branch, &sb))
 621                 return;
 622         fputs(sb.buf, stdout);
 623         strbuf_release(&sb);
 624 }
 625
 626 static void update_refs_for_switch(const struct checkout_opts *opts,
 627                                    struct branch_info *old,
 628                                    struct branch_info *new)
 629 {
 630         struct strbuf msg = STRBUF_INIT;
 631         const char *old_desc, *reflog_msg;
 632         if (opts->new_branch) {
 633                 if (opts->new_orphan_branch) {
 634                         char *refname;
 635
 636                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 637                         if (opts->new_branch_log &&
 638                             !should_autocreate_reflog(refname)) {
 639                                 int ret;
 640                                 struct strbuf err = STRBUF_INIT;
 641
 642                                 ret = safe_create_reflog(refname, 1, &err);
 643                                 if (ret) {
 644                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 645                                                 opts->new_orphan_branch, err.buf);
 646                                         strbuf_release(&err);
 647                                         free(refname);
 648                                         return;
 649                                 }
 650                                 strbuf_release(&err);
 651                         }
 652                         free(refname);
 653                 }
 654                 else
 655                         create_branch(opts->new_branch, new->name,
 656                                       opts->new_branch_force ? 1 : 0,
 657                                       opts->new_branch_log,
 658                                       opts->new_branch_force ? 1 : 0,
 659                                       opts->quiet,
 660                                       opts->track);
 661                 new->name = opts->new_branch;
 662                 setup_branch_path(new);
 663         }
 664
 665         old_desc = old->name;
 666         if (!old_desc && old->commit)
 667                 old_desc = oid_to_hex(&old->commit->object.oid);
 668
 669         reflog_msg = getenv("GIT_REFLOG_ACTION");
 670         if (!reflog_msg)
 671                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 672                         old_desc ? old_desc : "(invalid)", new->name);
 673         else
 674                 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
 675
 676         if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
 677                 /* Nothing to do. */
 678         } else if (opts->force_detach || !new->path) {  /* No longer on any branch. */
 679                 update_ref(msg.buf, "HEAD", new->commit->object.oid.hash, NULL,
 680                            REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
 681                 if (!opts->quiet) {
 682                         if (old->path &&
 683                             advice_detached_head && !opts->force_detach)
 684                                 detach_advice(new->name);
 685                         describe_detached_head(_("HEAD is now at"), new->commit);
 686                 }
 687         } else if (new->path) { /* Switch branches. */
 688                 if (create_symref("HEAD", new->path, msg.buf) < 0)
 689                         die(_("unable to update HEAD"));
 690                 if (!opts->quiet) {
 691                         if (old->path && !strcmp(new->path, old->path)) {
 692                                 if (opts->new_branch_force)
 693                                         fprintf(stderr, _("Reset branch '%s'\n"),
 694                                                 new->name);
 695                                 else
 696                                         fprintf(stderr, _("Already on '%s'\n"),
 697                                                 new->name);
 698                         } else if (opts->new_branch) {
 699                                 if (opts->branch_exists)
 700                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new->name);
 701                                 else
 702                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new->name);
 703                         } else {
 704                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 705                                         new->name);
 706                         }
 707                 }
 708                 if (old->path && old->name) {
 709                         if (!ref_exists(old->path) && reflog_exists(old->path))
 710                                 delete_reflog(old->path);
 711                 }
 712         }
 713         remove_branch_state();
 714         strbuf_release(&msg);
 715         if (!opts->quiet &&
 716             (new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
 717                 report_tracking(new);
 718 }
 719
 720 static int add_pending_uninteresting_ref(const char *refname,
 721                                          const struct object_id *oid,
 722                                          int flags, void *cb_data)
 723 {
 724         add_pending_sha1(cb_data, refname, oid->hash, UNINTERESTING);
 725         return 0;
 726 }
 727
 728 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 729 {
 730         strbuf_addstr(sb, "  ");
 731         strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
 732         strbuf_addch(sb, ' ');
 733         if (!parse_commit(commit))
 734                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 735         strbuf_addch(sb, '\n');
 736 }
 737
 738 #define ORPHAN_CUTOFF 4
 739 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 740 {
 741         struct commit *c, *last = NULL;
 742         struct strbuf sb = STRBUF_INIT;
 743         int lost = 0;
 744         while ((c = get_revision(revs)) != NULL) {
 745                 if (lost < ORPHAN_CUTOFF)
 746                         describe_one_orphan(&sb, c);
 747                 last = c;
 748                 lost++;
 749         }
 750         if (ORPHAN_CUTOFF < lost) {
 751                 int more = lost - ORPHAN_CUTOFF;
 752                 if (more == 1)
 753                         describe_one_orphan(&sb, last);
 754                 else
 755                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 756         }
 757
 758         fprintf(stderr,
 759                 Q_(
 760                 /* The singular version */
 761                 "Warning: you are leaving %d commit behind, "
 762                 "not connected to\n"
 763                 "any of your branches:\n\n"
 764                 "%s\n",
 765                 /* The plural version */
 766                 "Warning: you are leaving %d commits behind, "
 767                 "not connected to\n"
 768                 "any of your branches:\n\n"
 769                 "%s\n",
 770                 /* Give ngettext() the count */
 771                 lost),
 772                 lost,
 773                 sb.buf);
 774         strbuf_release(&sb);
 775
 776         if (advice_detached_head)
 777                 fprintf(stderr,
 778                         Q_(
 779                         /* The singular version */
 780                         "If you want to keep it by creating a new branch, "
 781                         "this may be a good time\nto do so with:\n\n"
 782                         " git branch <new-branch-name> %s\n\n",
 783                         /* The plural version */
 784                         "If you want to keep them by creating a new branch, "
 785                         "this may be a good time\nto do so with:\n\n"
 786                         " git branch <new-branch-name> %s\n\n",
 787                         /* Give ngettext() the count */
 788                         lost),
 789                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
 790 }
 791
 792 /*
 793  * We are about to leave commit that was at the tip of a detached
 794  * HEAD.  If it is not reachable from any ref, this is the last chance
 795  * for the user to do so without resorting to reflog.
 796  */
 797 static void orphaned_commit_warning(struct commit *old, struct commit *new)
 798 {
 799         struct rev_info revs;
 800         struct object *object = &old->object;
 801         struct object_array refs;
 802
 803         init_revisions(&revs, NULL);
 804         setup_revisions(0, NULL, &revs, NULL);
 805
 806         object->flags &= ~UNINTERESTING;
 807         add_pending_object(&revs, object, oid_to_hex(&object->oid));
 808
 809         for_each_ref(add_pending_uninteresting_ref, &revs);
 810         add_pending_sha1(&revs, "HEAD", new->object.oid.hash, UNINTERESTING);
 811
 812         refs = revs.pending;
 813         revs.leak_pending = 1;
 814
 815         if (prepare_revision_walk(&revs))
 816                 die(_("internal error in revision walk"));
 817         if (!(old->object.flags & UNINTERESTING))
 818                 suggest_reattach(old, &revs);
 819         else
 820                 describe_detached_head(_("Previous HEAD position was"), old);
 821
 822         clear_commit_marks_for_object_array(&refs, ALL_REV_FLAGS);
 823         free(refs.objects);
 824 }
 825
 826 static int switch_branches(const struct checkout_opts *opts,
 827                            struct branch_info *new)
 828 {
 829         int ret = 0;
 830         struct branch_info old;
 831         void *path_to_free;
 832         struct object_id rev;
 833         int flag, writeout_error = 0;
 834         memset(&old, 0, sizeof(old));
 835         old.path = path_to_free = resolve_refdup("HEAD", 0, rev.hash, &flag);
 836         old.commit = lookup_commit_reference_gently(rev.hash, 1);
 837         if (!(flag & REF_ISSYMREF))
 838                 old.path = NULL;
 839
 840         if (old.path)
 841                 skip_prefix(old.path, "refs/heads/", &old.name);
 842
 843         if (!new->name) {
 844                 new->name = "HEAD";
 845                 new->commit = old.commit;
 846                 if (!new->commit)
 847                         die(_("You are on a branch yet to be born"));
 848                 parse_commit_or_die(new->commit);
 849         }
 850
 851         ret = merge_working_tree(opts, &old, new, &writeout_error);
 852         if (ret) {
 853                 free(path_to_free);
 854                 return ret;
 855         }
 856
 857         if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
 858                 orphaned_commit_warning(old.commit, new->commit);
 859
 860         update_refs_for_switch(opts, &old, new);
 861
 862         ret = post_checkout_hook(old.commit, new->commit, 1);
 863         free(path_to_free);
 864         return ret || writeout_error;
 865 }
 866
 867 static int git_checkout_config(const char *var, const char *value, void *cb)
 868 {
 869         if (!strcmp(var, "diff.ignoresubmodules")) {
 870                 struct checkout_opts *opts = cb;
 871                 handle_ignore_submodules_arg(&opts->diff_options, value);
 872                 return 0;
 873         }
 874
 875         if (starts_with(var, "submodule."))
 876                 return parse_submodule_config_option(var, value);
 877
 878         return git_xmerge_config(var, value, NULL);
 879 }
 880
 881 struct tracking_name_data {
 882         /* const */ char *src_ref;
 883         char *dst_ref;
 884         struct object_id *dst_oid;
 885         int unique;
 886 };
 887
 888 static int check_tracking_name(struct remote *remote, void *cb_data)
 889 {
 890         struct tracking_name_data *cb = cb_data;
 891         struct refspec query;
 892         memset(&query, 0, sizeof(struct refspec));
 893         query.src = cb->src_ref;
 894         if (remote_find_tracking(remote, &query) ||
 895             get_oid(query.dst, cb->dst_oid)) {
 896                 free(query.dst);
 897                 return 0;
 898         }
 899         if (cb->dst_ref) {
 900                 free(query.dst);
 901                 cb->unique = 0;
 902                 return 0;
 903         }
 904         cb->dst_ref = query.dst;
 905         return 0;
 906 }
 907
 908 static const char *unique_tracking_name(const char *name, struct object_id *oid)
 909 {
 910         struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
 911         cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 912         cb_data.dst_oid = oid;
 913         for_each_remote(check_tracking_name, &cb_data);
 914         free(cb_data.src_ref);
 915         if (cb_data.unique)
 916                 return cb_data.dst_ref;
 917         free(cb_data.dst_ref);
 918         return NULL;
 919 }
 920
 921 static int parse_branchname_arg(int argc, const char **argv,
 922                                 int dwim_new_local_branch_ok,
 923                                 struct branch_info *new,
 924                                 struct checkout_opts *opts,
 925                                 struct object_id *rev)
 926 {
 927         struct tree **source_tree = &opts->source_tree;
 928         const char **new_branch = &opts->new_branch;
 929         int argcount = 0;
 930         struct object_id branch_rev;
 931         const char *arg;
 932         int dash_dash_pos;
 933         int has_dash_dash = 0;
 934         int i;
 935
 936         /*
 937          * case 1: git checkout <ref> -- [<paths>]
 938          *
 939          *   <ref> must be a valid tree, everything after the '--' must be
 940          *   a path.
 941          *
 942          * case 2: git checkout -- [<paths>]
 943          *
 944          *   everything after the '--' must be paths.
 945          *
 946          * case 3: git checkout <something> [--]
 947          *
 948          *   (a) If <something> is a commit, that is to
 949          *       switch to the branch or detach HEAD at it.  As a special case,
 950          *       if <something> is A...B (missing A or B means HEAD but you can
 951          *       omit at most one side), and if there is a unique merge base
 952          *       between A and B, A...B names that merge base.
 953          *
 954          *   (b) If <something> is _not_ a commit, either "--" is present
 955          *       or <something> is not a path, no -t or -b was given, and
 956          *       and there is a tracking branch whose name is <something>
 957          *       in one and only one remote, then this is a short-hand to
 958          *       fork local <something> from that remote-tracking branch.
 959          *
 960          *   (c) Otherwise, if "--" is present, treat it like case (1).
 961          *
 962          *   (d) Otherwise :
 963          *       - if it's a reference, treat it like case (1)
 964          *       - else if it's a path, treat it like case (2)
 965          *       - else: fail.
 966          *
 967          * case 4: git checkout <something> <paths>
 968          *
 969          *   The first argument must not be ambiguous.
 970          *   - If it's *only* a reference, treat it like case (1).
 971          *   - If it's only a path, treat it like case (2).
 972          *   - else: fail.
 973          *
 974          */
 975         if (!argc)
 976                 return 0;
 977
 978         arg = argv[0];
 979         dash_dash_pos = -1;
 980         for (i = 0; i < argc; i++) {
 981                 if (!strcmp(argv[i], "--")) {
 982                         dash_dash_pos = i;
 983                         break;
 984                 }
 985         }
 986         if (dash_dash_pos == 0)
 987                 return 1; /* case (2) */
 988         else if (dash_dash_pos == 1)
 989                 has_dash_dash = 1; /* case (3) or (1) */
 990         else if (dash_dash_pos >= 2)
 991                 die(_("only one reference expected, %d given."), dash_dash_pos);
 992
 993         if (!strcmp(arg, "-"))
 994                 arg = "@{-1}";
 995
 996         if (get_oid_mb(arg, rev)) {
 997                 /*
 998                  * Either case (3) or (4), with <something> not being
 999                  * a commit, or an attempt to use case (1) with an
1000                  * invalid ref.
1001                  *
1002                  * It's likely an error, but we need to find out if
1003                  * we should auto-create the branch, case (3).(b).
1004                  */
1005                 int recover_with_dwim = dwim_new_local_branch_ok;
1006
1007                 if (!has_dash_dash &&
1008                     (check_filename(opts->prefix, arg) || !no_wildcard(arg)))
1009                         recover_with_dwim = 0;
1010                 /*
1011                  * Accept "git checkout foo" and "git checkout foo --"
1012                  * as candidates for dwim.
1013                  */
1014                 if (!(argc == 1 && !has_dash_dash) &&
1015                     !(argc == 2 && has_dash_dash))
1016                         recover_with_dwim = 0;
1017
1018                 if (recover_with_dwim) {
1019                         const char *remote = unique_tracking_name(arg, rev);
1020                         if (remote) {
1021                                 *new_branch = arg;
1022                                 arg = remote;
1023                                 /* DWIMmed to create local branch, case (3).(b) */
1024                         } else {
1025                                 recover_with_dwim = 0;
1026                         }
1027                 }
1028
1029                 if (!recover_with_dwim) {
1030                         if (has_dash_dash)
1031                                 die(_("invalid reference: %s"), arg);
1032                         return argcount;
1033                 }
1034         }
1035
1036         /* we can't end up being in (2) anymore, eat the argument */
1037         argcount++;
1038         argv++;
1039         argc--;
1040
1041         new->name = arg;
1042         setup_branch_path(new);
1043
1044         if (!check_refname_format(new->path, 0) &&
1045             !read_ref(new->path, branch_rev.hash))
1046                 oidcpy(rev, &branch_rev);
1047         else
1048                 new->path = NULL; /* not an existing branch */
1049
1050         new->commit = lookup_commit_reference_gently(rev->hash, 1);
1051         if (!new->commit) {
1052                 /* not a commit */
1053                 *source_tree = parse_tree_indirect(rev->hash);
1054         } else {
1055                 parse_commit_or_die(new->commit);
1056                 *source_tree = new->commit->tree;
1057         }
1058
1059         if (!*source_tree)                   /* case (1): want a tree */
1060                 die(_("reference is not a tree: %s"), arg);
1061         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1062                 /*
1063                  * Do not complain the most common case
1064                  *      git checkout branch
1065                  * even if there happen to be a file called 'branch';
1066                  * it would be extremely annoying.
1067                  */
1068                 if (argc)
1069                         verify_non_filename(opts->prefix, arg);
1070         } else {
1071                 argcount++;
1072                 argv++;
1073                 argc--;
1074         }
1075
1076         return argcount;
1077 }
1078
1079 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1080 {
1081         int status;
1082         struct strbuf branch_ref = STRBUF_INIT;
1083
1084         if (!opts->new_branch)
1085                 die(_("You are on a branch yet to be born"));
1086         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1087         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1088         strbuf_release(&branch_ref);
1089         if (!opts->quiet)
1090                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1091                         opts->new_branch);
1092         return status;
1093 }
1094
1095 static int checkout_branch(struct checkout_opts *opts,
1096                            struct branch_info *new)
1097 {
1098         if (opts->pathspec.nr)
1099                 die(_("paths cannot be used with switching branches"));
1100
1101         if (opts->patch_mode)
1102                 die(_("'%s' cannot be used with switching branches"),
1103                     "--patch");
1104
1105         if (opts->writeout_stage)
1106                 die(_("'%s' cannot be used with switching branches"),
1107                     "--ours/--theirs");
1108
1109         if (opts->force && opts->merge)
1110                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1111
1112         if (opts->force_detach && opts->new_branch)
1113                 die(_("'%s' cannot be used with '%s'"),
1114                     "--detach", "-b/-B/--orphan");
1115
1116         if (opts->new_orphan_branch) {
1117                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1118                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1119         } else if (opts->force_detach) {
1120                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1121                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1122         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1123                 opts->track = git_branch_track;
1124
1125         if (new->name && !new->commit)
1126                 die(_("Cannot switch branch to a non-commit '%s'"),
1127                     new->name);
1128
1129         if (new->path && !opts->force_detach && !opts->new_branch &&
1130             !opts->ignore_other_worktrees) {
1131                 struct object_id oid;
1132                 int flag;
1133                 char *head_ref = resolve_refdup("HEAD", 0, oid.hash, &flag);
1134                 if (head_ref &&
1135                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
1136                         die_if_checked_out(new->path, 1);
1137                 free(head_ref);
1138         }
1139
1140         if (!new->commit && opts->new_branch) {
1141                 struct object_id rev;
1142                 int flag;
1143
1144                 if (!read_ref_full("HEAD", 0, rev.hash, &flag) &&
1145                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1146                         return switch_unborn_to_new_branch(opts);
1147         }
1148         return switch_branches(opts, new);
1149 }
1150
1151 int cmd_checkout(int argc, const char **argv, const char *prefix)
1152 {
1153         struct checkout_opts opts;
1154         struct branch_info new;
1155         char *conflict_style = NULL;
1156         int dwim_new_local_branch = 1;
1157         struct option options[] = {
1158                 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1159                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1160                            N_("create and checkout a new branch")),
1161                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1162                            N_("create/reset and checkout a branch")),
1163                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1164                 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1165                 OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
1166                         BRANCH_TRACK_EXPLICIT),
1167                 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1168                 OPT_SET_INT('2', "ours", &opts.writeout_stage, N_("checkout our version for unmerged files"),
1169                             2),
1170                 OPT_SET_INT('3', "theirs", &opts.writeout_stage, N_("checkout their version for unmerged files"),
1171                             3),
1172                 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)")),
1173                 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1174                 OPT_BOOL(0, "overwrite-ignore", &opts.overwrite_ignore, N_("update ignored files (default)")),
1175                 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1176                            N_("conflict style (merge or diff3)")),
1177                 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1178                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1179                          N_("do not limit pathspecs to sparse entries only")),
1180                 OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
1181                                 N_("second guess 'git checkout <no-such-branch>'")),
1182                 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1183                          N_("do not check if another worktree is holding the given ref")),
1184                 { OPTION_CALLBACK, 0, "recurse-submodules", &recurse_submodules,
1185                             "checkout", "control recursive updating of submodules",
1186                             PARSE_OPT_OPTARG, option_parse_recurse_submodules },
1187                 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1188                 OPT_END(),
1189         };
1190
1191         memset(&opts, 0, sizeof(opts));
1192         memset(&new, 0, sizeof(new));
1193         opts.overwrite_ignore = 1;
1194         opts.prefix = prefix;
1195         opts.show_progress = -1;
1196
1197         gitmodules_config();
1198         git_config(git_checkout_config, &opts);
1199
1200         opts.track = BRANCH_TRACK_UNSPECIFIED;
1201
1202         argc = parse_options(argc, argv, prefix, options, checkout_usage,
1203                              PARSE_OPT_KEEP_DASHDASH);
1204
1205         if (opts.show_progress < 0) {
1206                 if (opts.quiet)
1207                         opts.show_progress = 0;
1208                 else
1209                         opts.show_progress = isatty(2);
1210         }
1211
1212         if (conflict_style) {
1213                 opts.merge = 1; /* implied */
1214                 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1215         }
1216
1217         if (recurse_submodules != RECURSE_SUBMODULES_OFF) {
1218                 git_config(submodule_config, NULL);
1219                 if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
1220                         set_config_update_recurse_submodules(recurse_submodules);
1221         }
1222
1223         if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1224                 die(_("-b, -B and --orphan are mutually exclusive"));
1225
1226         /*
1227          * From here on, new_branch will contain the branch to be checked out,
1228          * and new_branch_force and new_orphan_branch will tell us which one of
1229          * -b/-B/--orphan is being used.
1230          */
1231         if (opts.new_branch_force)
1232                 opts.new_branch = opts.new_branch_force;
1233
1234         if (opts.new_orphan_branch)
1235                 opts.new_branch = opts.new_orphan_branch;
1236
1237         /* --track without -b/-B/--orphan should DWIM */
1238         if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1239                 const char *argv0 = argv[0];
1240                 if (!argc || !strcmp(argv0, "--"))
1241                         die (_("--track needs a branch name"));
1242                 skip_prefix(argv0, "refs/", &argv0);
1243                 skip_prefix(argv0, "remotes/", &argv0);
1244                 argv0 = strchr(argv0, '/');
1245                 if (!argv0 || !argv0[1])
1246                         die (_("Missing branch name; try -b"));
1247                 opts.new_branch = argv0 + 1;
1248         }
1249
1250         /*
1251          * Extract branch name from command line arguments, so
1252          * all that is left is pathspecs.
1253          *
1254          * Handle
1255          *
1256          *  1) git checkout <tree> -- [<paths>]
1257          *  2) git checkout -- [<paths>]
1258          *  3) git checkout <something> [<paths>]
1259          *
1260          * including "last branch" syntax and DWIM-ery for names of
1261          * remote branches, erroring out for invalid or ambiguous cases.
1262          */
1263         if (argc) {
1264                 struct object_id rev;
1265                 int dwim_ok =
1266                         !opts.patch_mode &&
1267                         dwim_new_local_branch &&
1268                         opts.track == BRANCH_TRACK_UNSPECIFIED &&
1269                         !opts.new_branch;
1270                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1271                                              &new, &opts, &rev);
1272                 argv += n;
1273                 argc -= n;
1274         }
1275
1276         if (argc) {
1277                 parse_pathspec(&opts.pathspec, 0,
1278                                opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1279                                prefix, argv);
1280
1281                 if (!opts.pathspec.nr)
1282                         die(_("invalid path specification"));
1283
1284                 /*
1285                  * Try to give more helpful suggestion.
1286                  * new_branch && argc > 1 will be caught later.
1287                  */
1288                 if (opts.new_branch && argc == 1)
1289                         die(_("Cannot update paths and switch to branch '%s' at the same time.\n"
1290                               "Did you intend to checkout '%s' which can not be resolved as commit?"),
1291                             opts.new_branch, argv[0]);
1292
1293                 if (opts.force_detach)
1294                         die(_("git checkout: --detach does not take a path argument '%s'"),
1295                             argv[0]);
1296
1297                 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1298                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1299                               "checking out of the index."));
1300         }
1301
1302         if (opts.new_branch) {
1303                 struct strbuf buf = STRBUF_INIT;
1304
1305                 opts.branch_exists =
1306                         validate_new_branchname(opts.new_branch, &buf,
1307                                                 !!opts.new_branch_force,
1308                                                 !!opts.new_branch_force);
1309
1310                 strbuf_release(&buf);
1311         }
1312
1313         if (opts.patch_mode || opts.pathspec.nr)
1314                 return checkout_paths(&opts, new.name);
1315         else
1316                 return checkout_branch(&opts, &new);
1317 }