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.  This hack is primarily to get
 239          * to the write_entry() machinery that massages the contents to
 240          * work-tree format and writes out which only allows it for a
 241          * cache entry.  The code in write_entry() needs to be refactored
 242          * to allow us to feed a <buffer, size, mode> instead of a cache
 243          * entry.  Such a refactoring would help merge_recursive as well
 244          * (it also writes the merge result to the object database even
 245          * 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         free(result_buf.ptr);
 251         ce = make_cache_entry(mode, oid.hash, path, 2, 0);
 252         if (!ce)
 253                 die(_("make_cache_entry failed for path '%s'"), path);
 254         status = checkout_entry(ce, state, NULL);
 255         free(ce);
 256         return status;
 257 }
 258
 259 static int checkout_paths(const struct checkout_opts *opts,
 260                           const char *revision)
 261 {
 262         int pos;
 263         struct checkout state = CHECKOUT_INIT;
 264         static char *ps_matched;
 265         struct object_id rev;
 266         struct commit *head;
 267         int errs = 0;
 268         struct lock_file *lock_file;
 269
 270         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 271                 die(_("'%s' cannot be used with updating paths"), "--track");
 272
 273         if (opts->new_branch_log)
 274                 die(_("'%s' cannot be used with updating paths"), "-l");
 275
 276         if (opts->force && opts->patch_mode)
 277                 die(_("'%s' cannot be used with updating paths"), "-f");
 278
 279         if (opts->force_detach)
 280                 die(_("'%s' cannot be used with updating paths"), "--detach");
 281
 282         if (opts->merge && opts->patch_mode)
 283                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 284
 285         if (opts->force && opts->merge)
 286                 die(_("'%s' cannot be used with %s"), "-f", "-m");
 287
 288         if (opts->new_branch)
 289                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 290                     opts->new_branch);
 291
 292         if (opts->patch_mode)
 293                 return run_add_interactive(revision, "--patch=checkout",
 294                                            &opts->pathspec);
 295
 296         lock_file = xcalloc(1, sizeof(struct lock_file));
 297
 298         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 299         if (read_cache_preload(&opts->pathspec) < 0)
 300                 return error(_("index file corrupt"));
 301
 302         if (opts->source_tree)
 303                 read_tree_some(opts->source_tree, &opts->pathspec);
 304
 305         ps_matched = xcalloc(opts->pathspec.nr, 1);
 306
 307         /*
 308          * Make sure all pathspecs participated in locating the paths
 309          * to be checked out.
 310          */
 311         for (pos = 0; pos < active_nr; pos++) {
 312                 struct cache_entry *ce = active_cache[pos];
 313                 ce->ce_flags &= ~CE_MATCHED;
 314                 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 315                         continue;
 316                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 317                         /*
 318                          * "git checkout tree-ish -- path", but this entry
 319                          * is in the original index; it will not be checked
 320                          * out to the working tree and it does not matter
 321                          * if pathspec matched this entry.  We will not do
 322                          * anything to this entry at all.
 323                          */
 324                         continue;
 325                 /*
 326                  * Either this entry came from the tree-ish we are
 327                  * checking the paths out of, or we are checking out
 328                  * of the index.
 329                  *
 330                  * If it comes from the tree-ish, we already know it
 331                  * matches the pathspec and could just stamp
 332                  * CE_MATCHED to it from update_some(). But we still
 333                  * need ps_matched and read_tree_recursive (and
 334                  * eventually tree_entry_interesting) cannot fill
 335                  * ps_matched yet. Once it can, we can avoid calling
 336                  * match_pathspec() for _all_ entries when
 337                  * opts->source_tree != NULL.
 338                  */
 339                 if (ce_path_match(ce, &opts->pathspec, ps_matched))
 340                         ce->ce_flags |= CE_MATCHED;
 341         }
 342
 343         if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
 344                 free(ps_matched);
 345                 return 1;
 346         }
 347         free(ps_matched);
 348
 349         /* "checkout -m path" to recreate conflicted state */
 350         if (opts->merge)
 351                 unmerge_marked_index(&the_index);
 352
 353         /* Any unmerged paths? */
 354         for (pos = 0; pos < active_nr; pos++) {
 355                 const struct cache_entry *ce = active_cache[pos];
 356                 if (ce->ce_flags & CE_MATCHED) {
 357                         if (!ce_stage(ce))
 358                                 continue;
 359                         if (opts->force) {
 360                                 warning(_("path '%s' is unmerged"), ce->name);
 361                         } else if (opts->writeout_stage) {
 362                                 errs |= check_stage(opts->writeout_stage, ce, pos);
 363                         } else if (opts->merge) {
 364                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 365                         } else {
 366                                 errs = 1;
 367                                 error(_("path '%s' is unmerged"), ce->name);
 368                         }
 369                         pos = skip_same_name(ce, pos) - 1;
 370                 }
 371         }
 372         if (errs)
 373                 return 1;
 374
 375         /* Now we are committed to check them out */
 376         state.force = 1;
 377         state.refresh_cache = 1;
 378         state.istate = &the_index;
 379
 380         enable_delayed_checkout(&state);
 381         for (pos = 0; pos < active_nr; pos++) {
 382                 struct cache_entry *ce = active_cache[pos];
 383                 if (ce->ce_flags & CE_MATCHED) {
 384                         if (!ce_stage(ce)) {
 385                                 errs |= checkout_entry(ce, &state, NULL);
 386                                 continue;
 387                         }
 388                         if (opts->writeout_stage)
 389                                 errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
 390                         else if (opts->merge)
 391                                 errs |= checkout_merged(pos, &state);
 392                         pos = skip_same_name(ce, pos) - 1;
 393                 }
 394         }
 395         errs |= finish_delayed_checkout(&state);
 396
 397         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 398                 die(_("unable to write new index file"));
 399
 400         read_ref_full("HEAD", 0, rev.hash, NULL);
 401         head = lookup_commit_reference_gently(&rev, 1);
 402
 403         errs |= post_checkout_hook(head, head, 0);
 404         return errs;
 405 }
 406
 407 static void show_local_changes(struct object *head,
 408                                const struct diff_options *opts)
 409 {
 410         struct rev_info rev;
 411         /* I think we want full paths, even if we're in a subdirectory. */
 412         init_revisions(&rev, NULL);
 413         rev.diffopt.flags = opts->flags;
 414         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 415         diff_setup_done(&rev.diffopt);
 416         add_pending_object(&rev, head, NULL);
 417         run_diff_index(&rev, 0);
 418 }
 419
 420 static void describe_detached_head(const char *msg, struct commit *commit)
 421 {
 422         struct strbuf sb = STRBUF_INIT;
 423         if (!parse_commit(commit))
 424                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 425         fprintf(stderr, "%s %s... %s\n", msg,
 426                 find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
 427         strbuf_release(&sb);
 428 }
 429
 430 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 431                       int worktree, int *writeout_error)
 432 {
 433         struct unpack_trees_options opts;
 434         struct tree_desc tree_desc;
 435
 436         memset(&opts, 0, sizeof(opts));
 437         opts.head_idx = -1;
 438         opts.update = worktree;
 439         opts.skip_unmerged = !worktree;
 440         opts.reset = 1;
 441         opts.merge = 1;
 442         opts.fn = oneway_merge;
 443         opts.verbose_update = o->show_progress;
 444         opts.src_index = &the_index;
 445         opts.dst_index = &the_index;
 446         parse_tree(tree);
 447         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 448         switch (unpack_trees(1, &tree_desc, &opts)) {
 449         case -2:
 450                 *writeout_error = 1;
 451                 /*
 452                  * We return 0 nevertheless, as the index is all right
 453                  * and more importantly we have made best efforts to
 454                  * update paths in the work tree, and we cannot revert
 455                  * them.
 456                  */
 457         case 0:
 458                 return 0;
 459         default:
 460                 return 128;
 461         }
 462 }
 463
 464 struct branch_info {
 465         const char *name; /* The short name used */
 466         const char *path; /* The full name of a real branch */
 467         struct commit *commit; /* The named commit */
 468         /*
 469          * if not null the branch is detached because it's already
 470          * checked out in this checkout
 471          */
 472         char *checkout;
 473 };
 474
 475 static void setup_branch_path(struct branch_info *branch)
 476 {
 477         struct strbuf buf = STRBUF_INIT;
 478
 479         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 480         if (strcmp(buf.buf, branch->name))
 481                 branch->name = xstrdup(buf.buf);
 482         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 483         branch->path = strbuf_detach(&buf, NULL);
 484 }
 485
 486 static int merge_working_tree(const struct checkout_opts *opts,
 487                               struct branch_info *old,
 488                               struct branch_info *new,
 489                               int *writeout_error)
 490 {
 491         int ret;
 492         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 493
 494         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 495         if (read_cache_preload(NULL) < 0)
 496                 return error(_("index file corrupt"));
 497
 498         resolve_undo_clear();
 499         if (opts->force) {
 500                 ret = reset_tree(new->commit->tree, opts, 1, writeout_error);
 501                 if (ret)
 502                         return ret;
 503         } else {
 504                 struct tree_desc trees[2];
 505                 struct tree *tree;
 506                 struct unpack_trees_options topts;
 507
 508                 memset(&topts, 0, sizeof(topts));
 509                 topts.head_idx = -1;
 510                 topts.src_index = &the_index;
 511                 topts.dst_index = &the_index;
 512
 513                 setup_unpack_trees_porcelain(&topts, "checkout");
 514
 515                 refresh_cache(REFRESH_QUIET);
 516
 517                 if (unmerged_cache()) {
 518                         error(_("you need to resolve your current index first"));
 519                         return 1;
 520                 }
 521
 522                 /* 2-way merge to the new branch */
 523                 topts.initial_checkout = is_cache_unborn();
 524                 topts.update = 1;
 525                 topts.merge = 1;
 526                 topts.gently = opts->merge && old->commit;
 527                 topts.verbose_update = opts->show_progress;
 528                 topts.fn = twoway_merge;
 529                 if (opts->overwrite_ignore) {
 530                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 531                         topts.dir->flags |= DIR_SHOW_IGNORED;
 532                         setup_standard_excludes(topts.dir);
 533                 }
 534                 tree = parse_tree_indirect(old->commit ?
 535                                            &old->commit->object.oid :
 536                                            &empty_tree_oid);
 537                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 538                 tree = parse_tree_indirect(&new->commit->object.oid);
 539                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 540
 541                 ret = unpack_trees(2, trees, &topts);
 542                 if (ret == -1) {
 543                         /*
 544                          * Unpack couldn't do a trivial merge; either
 545                          * give up or do a real merge, depending on
 546                          * whether the merge flag was used.
 547                          */
 548                         struct tree *result;
 549                         struct tree *work;
 550                         struct merge_options o;
 551                         if (!opts->merge)
 552                                 return 1;
 553
 554                         /*
 555                          * Without old->commit, the below is the same as
 556                          * the two-tree unpack we already tried and failed.
 557                          */
 558                         if (!old->commit)
 559                                 return 1;
 560
 561                         /* Do more real merge */
 562
 563                         /*
 564                          * We update the index fully, then write the
 565                          * tree from the index, then merge the new
 566                          * branch with the current tree, with the old
 567                          * branch as the base. Then we reset the index
 568                          * (but not the working tree) to the new
 569                          * branch, leaving the working tree as the
 570                          * merged version, but skipping unmerged
 571                          * entries in the index.
 572                          */
 573
 574                         add_files_to_cache(NULL, NULL, 0);
 575                         /*
 576                          * NEEDSWORK: carrying over local changes
 577                          * when branches have different end-of-line
 578                          * normalization (or clean+smudge rules) is
 579                          * a pain; plumb in an option to set
 580                          * o.renormalize?
 581                          */
 582                         init_merge_options(&o);
 583                         o.verbosity = 0;
 584                         work = write_tree_from_memory(&o);
 585
 586                         ret = reset_tree(new->commit->tree, opts, 1,
 587                                          writeout_error);
 588                         if (ret)
 589                                 return ret;
 590                         o.ancestor = old->name;
 591                         o.branch1 = new->name;
 592                         o.branch2 = "local";
 593                         ret = merge_trees(&o, new->commit->tree, work,
 594                                 old->commit->tree, &result);
 595                         if (ret < 0)
 596                                 exit(128);
 597                         ret = reset_tree(new->commit->tree, opts, 0,
 598                                          writeout_error);
 599                         strbuf_release(&o.obuf);
 600                         if (ret)
 601                                 return ret;
 602                 }
 603         }
 604
 605         if (!active_cache_tree)
 606                 active_cache_tree = cache_tree();
 607
 608         if (!cache_tree_fully_valid(active_cache_tree))
 609                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 610
 611         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 612                 die(_("unable to write new index file"));
 613
 614         if (!opts->force && !opts->quiet)
 615                 show_local_changes(&new->commit->object, &opts->diff_options);
 616
 617         return 0;
 618 }
 619
 620 static void report_tracking(struct branch_info *new)
 621 {
 622         struct strbuf sb = STRBUF_INIT;
 623         struct branch *branch = branch_get(new->name);
 624
 625         if (!format_tracking_info(branch, &sb))
 626                 return;
 627         fputs(sb.buf, stdout);
 628         strbuf_release(&sb);
 629 }
 630
 631 static void update_refs_for_switch(const struct checkout_opts *opts,
 632                                    struct branch_info *old,
 633                                    struct branch_info *new)
 634 {
 635         struct strbuf msg = STRBUF_INIT;
 636         const char *old_desc, *reflog_msg;
 637         if (opts->new_branch) {
 638                 if (opts->new_orphan_branch) {
 639                         char *refname;
 640
 641                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 642                         if (opts->new_branch_log &&
 643                             !should_autocreate_reflog(refname)) {
 644                                 int ret;
 645                                 struct strbuf err = STRBUF_INIT;
 646
 647                                 ret = safe_create_reflog(refname, 1, &err);
 648                                 if (ret) {
 649                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 650                                                 opts->new_orphan_branch, err.buf);
 651                                         strbuf_release(&err);
 652                                         free(refname);
 653                                         return;
 654                                 }
 655                                 strbuf_release(&err);
 656                         }
 657                         free(refname);
 658                 }
 659                 else
 660                         create_branch(opts->new_branch, new->name,
 661                                       opts->new_branch_force ? 1 : 0,
 662                                       opts->new_branch_log,
 663                                       opts->new_branch_force ? 1 : 0,
 664                                       opts->quiet,
 665                                       opts->track);
 666                 new->name = opts->new_branch;
 667                 setup_branch_path(new);
 668         }
 669
 670         old_desc = old->name;
 671         if (!old_desc && old->commit)
 672                 old_desc = oid_to_hex(&old->commit->object.oid);
 673
 674         reflog_msg = getenv("GIT_REFLOG_ACTION");
 675         if (!reflog_msg)
 676                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 677                         old_desc ? old_desc : "(invalid)", new->name);
 678         else
 679                 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
 680
 681         if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
 682                 /* Nothing to do. */
 683         } else if (opts->force_detach || !new->path) {  /* No longer on any branch. */
 684                 update_ref(msg.buf, "HEAD", new->commit->object.oid.hash, NULL,
 685                            REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
 686                 if (!opts->quiet) {
 687                         if (old->path &&
 688                             advice_detached_head && !opts->force_detach)
 689                                 detach_advice(new->name);
 690                         describe_detached_head(_("HEAD is now at"), new->commit);
 691                 }
 692         } else if (new->path) { /* Switch branches. */
 693                 if (create_symref("HEAD", new->path, msg.buf) < 0)
 694                         die(_("unable to update HEAD"));
 695                 if (!opts->quiet) {
 696                         if (old->path && !strcmp(new->path, old->path)) {
 697                                 if (opts->new_branch_force)
 698                                         fprintf(stderr, _("Reset branch '%s'\n"),
 699                                                 new->name);
 700                                 else
 701                                         fprintf(stderr, _("Already on '%s'\n"),
 702                                                 new->name);
 703                         } else if (opts->new_branch) {
 704                                 if (opts->branch_exists)
 705                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new->name);
 706                                 else
 707                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new->name);
 708                         } else {
 709                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 710                                         new->name);
 711                         }
 712                 }
 713                 if (old->path && old->name) {
 714                         if (!ref_exists(old->path) && reflog_exists(old->path))
 715                                 delete_reflog(old->path);
 716                 }
 717         }
 718         remove_branch_state();
 719         strbuf_release(&msg);
 720         if (!opts->quiet &&
 721             (new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
 722                 report_tracking(new);
 723 }
 724
 725 static int add_pending_uninteresting_ref(const char *refname,
 726                                          const struct object_id *oid,
 727                                          int flags, void *cb_data)
 728 {
 729         add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 730         return 0;
 731 }
 732
 733 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 734 {
 735         strbuf_addstr(sb, "  ");
 736         strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
 737         strbuf_addch(sb, ' ');
 738         if (!parse_commit(commit))
 739                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 740         strbuf_addch(sb, '\n');
 741 }
 742
 743 #define ORPHAN_CUTOFF 4
 744 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 745 {
 746         struct commit *c, *last = NULL;
 747         struct strbuf sb = STRBUF_INIT;
 748         int lost = 0;
 749         while ((c = get_revision(revs)) != NULL) {
 750                 if (lost < ORPHAN_CUTOFF)
 751                         describe_one_orphan(&sb, c);
 752                 last = c;
 753                 lost++;
 754         }
 755         if (ORPHAN_CUTOFF < lost) {
 756                 int more = lost - ORPHAN_CUTOFF;
 757                 if (more == 1)
 758                         describe_one_orphan(&sb, last);
 759                 else
 760                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 761         }
 762
 763         fprintf(stderr,
 764                 Q_(
 765                 /* The singular version */
 766                 "Warning: you are leaving %d commit behind, "
 767                 "not connected to\n"
 768                 "any of your branches:\n\n"
 769                 "%s\n",
 770                 /* The plural version */
 771                 "Warning: you are leaving %d commits behind, "
 772                 "not connected to\n"
 773                 "any of your branches:\n\n"
 774                 "%s\n",
 775                 /* Give ngettext() the count */
 776                 lost),
 777                 lost,
 778                 sb.buf);
 779         strbuf_release(&sb);
 780
 781         if (advice_detached_head)
 782                 fprintf(stderr,
 783                         Q_(
 784                         /* The singular version */
 785                         "If you want to keep it by creating a new branch, "
 786                         "this may be a good time\nto do so with:\n\n"
 787                         " git branch <new-branch-name> %s\n\n",
 788                         /* The plural version */
 789                         "If you want to keep them by creating a new branch, "
 790                         "this may be a good time\nto do so with:\n\n"
 791                         " git branch <new-branch-name> %s\n\n",
 792                         /* Give ngettext() the count */
 793                         lost),
 794                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
 795 }
 796
 797 /*
 798  * We are about to leave commit that was at the tip of a detached
 799  * HEAD.  If it is not reachable from any ref, this is the last chance
 800  * for the user to do so without resorting to reflog.
 801  */
 802 static void orphaned_commit_warning(struct commit *old, struct commit *new)
 803 {
 804         struct rev_info revs;
 805         struct object *object = &old->object;
 806         struct object_array refs;
 807
 808         init_revisions(&revs, NULL);
 809         setup_revisions(0, NULL, &revs, NULL);
 810
 811         object->flags &= ~UNINTERESTING;
 812         add_pending_object(&revs, object, oid_to_hex(&object->oid));
 813
 814         for_each_ref(add_pending_uninteresting_ref, &revs);
 815         add_pending_oid(&revs, "HEAD", &new->object.oid, UNINTERESTING);
 816
 817         refs = revs.pending;
 818         revs.leak_pending = 1;
 819
 820         if (prepare_revision_walk(&revs))
 821                 die(_("internal error in revision walk"));
 822         if (!(old->object.flags & UNINTERESTING))
 823                 suggest_reattach(old, &revs);
 824         else
 825                 describe_detached_head(_("Previous HEAD position was"), old);
 826
 827         clear_commit_marks_for_object_array(&refs, ALL_REV_FLAGS);
 828         free(refs.objects);
 829 }
 830
 831 static int switch_branches(const struct checkout_opts *opts,
 832                            struct branch_info *new)
 833 {
 834         int ret = 0;
 835         struct branch_info old;
 836         void *path_to_free;
 837         struct object_id rev;
 838         int flag, writeout_error = 0;
 839         memset(&old, 0, sizeof(old));
 840         old.path = path_to_free = resolve_refdup("HEAD", 0, rev.hash, &flag);
 841         if (old.path)
 842                 old.commit = lookup_commit_reference_gently(&rev, 1);
 843         if (!(flag & REF_ISSYMREF))
 844                 old.path = NULL;
 845
 846         if (old.path)
 847                 skip_prefix(old.path, "refs/heads/", &old.name);
 848
 849         if (!new->name) {
 850                 new->name = "HEAD";
 851                 new->commit = old.commit;
 852                 if (!new->commit)
 853                         die(_("You are on a branch yet to be born"));
 854                 parse_commit_or_die(new->commit);
 855         }
 856
 857         ret = merge_working_tree(opts, &old, new, &writeout_error);
 858         if (ret) {
 859                 free(path_to_free);
 860                 return ret;
 861         }
 862
 863         if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
 864                 orphaned_commit_warning(old.commit, new->commit);
 865
 866         update_refs_for_switch(opts, &old, new);
 867
 868         ret = post_checkout_hook(old.commit, new->commit, 1);
 869         free(path_to_free);
 870         return ret || writeout_error;
 871 }
 872
 873 static int git_checkout_config(const char *var, const char *value, void *cb)
 874 {
 875         if (!strcmp(var, "diff.ignoresubmodules")) {
 876                 struct checkout_opts *opts = cb;
 877                 handle_ignore_submodules_arg(&opts->diff_options, value);
 878                 return 0;
 879         }
 880
 881         if (starts_with(var, "submodule."))
 882                 return parse_submodule_config_option(var, value);
 883
 884         return git_xmerge_config(var, value, NULL);
 885 }
 886
 887 struct tracking_name_data {
 888         /* const */ char *src_ref;
 889         char *dst_ref;
 890         struct object_id *dst_oid;
 891         int unique;
 892 };
 893
 894 static int check_tracking_name(struct remote *remote, void *cb_data)
 895 {
 896         struct tracking_name_data *cb = cb_data;
 897         struct refspec query;
 898         memset(&query, 0, sizeof(struct refspec));
 899         query.src = cb->src_ref;
 900         if (remote_find_tracking(remote, &query) ||
 901             get_oid(query.dst, cb->dst_oid)) {
 902                 free(query.dst);
 903                 return 0;
 904         }
 905         if (cb->dst_ref) {
 906                 free(query.dst);
 907                 cb->unique = 0;
 908                 return 0;
 909         }
 910         cb->dst_ref = query.dst;
 911         return 0;
 912 }
 913
 914 static const char *unique_tracking_name(const char *name, struct object_id *oid)
 915 {
 916         struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
 917         cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 918         cb_data.dst_oid = oid;
 919         for_each_remote(check_tracking_name, &cb_data);
 920         free(cb_data.src_ref);
 921         if (cb_data.unique)
 922                 return cb_data.dst_ref;
 923         free(cb_data.dst_ref);
 924         return NULL;
 925 }
 926
 927 static int parse_branchname_arg(int argc, const char **argv,
 928                                 int dwim_new_local_branch_ok,
 929                                 struct branch_info *new,
 930                                 struct checkout_opts *opts,
 931                                 struct object_id *rev)
 932 {
 933         struct tree **source_tree = &opts->source_tree;
 934         const char **new_branch = &opts->new_branch;
 935         int argcount = 0;
 936         struct object_id branch_rev;
 937         const char *arg;
 938         int dash_dash_pos;
 939         int has_dash_dash = 0;
 940         int i;
 941
 942         /*
 943          * case 1: git checkout <ref> -- [<paths>]
 944          *
 945          *   <ref> must be a valid tree, everything after the '--' must be
 946          *   a path.
 947          *
 948          * case 2: git checkout -- [<paths>]
 949          *
 950          *   everything after the '--' must be paths.
 951          *
 952          * case 3: git checkout <something> [--]
 953          *
 954          *   (a) If <something> is a commit, that is to
 955          *       switch to the branch or detach HEAD at it.  As a special case,
 956          *       if <something> is A...B (missing A or B means HEAD but you can
 957          *       omit at most one side), and if there is a unique merge base
 958          *       between A and B, A...B names that merge base.
 959          *
 960          *   (b) If <something> is _not_ a commit, either "--" is present
 961          *       or <something> is not a path, no -t or -b was given, and
 962          *       and there is a tracking branch whose name is <something>
 963          *       in one and only one remote, then this is a short-hand to
 964          *       fork local <something> from that remote-tracking branch.
 965          *
 966          *   (c) Otherwise, if "--" is present, treat it like case (1).
 967          *
 968          *   (d) Otherwise :
 969          *       - if it's a reference, treat it like case (1)
 970          *       - else if it's a path, treat it like case (2)
 971          *       - else: fail.
 972          *
 973          * case 4: git checkout <something> <paths>
 974          *
 975          *   The first argument must not be ambiguous.
 976          *   - If it's *only* a reference, treat it like case (1).
 977          *   - If it's only a path, treat it like case (2).
 978          *   - else: fail.
 979          *
 980          */
 981         if (!argc)
 982                 return 0;
 983
 984         arg = argv[0];
 985         dash_dash_pos = -1;
 986         for (i = 0; i < argc; i++) {
 987                 if (!strcmp(argv[i], "--")) {
 988                         dash_dash_pos = i;
 989                         break;
 990                 }
 991         }
 992         if (dash_dash_pos == 0)
 993                 return 1; /* case (2) */
 994         else if (dash_dash_pos == 1)
 995                 has_dash_dash = 1; /* case (3) or (1) */
 996         else if (dash_dash_pos >= 2)
 997                 die(_("only one reference expected, %d given."), dash_dash_pos);
 998
 999         if (!strcmp(arg, "-"))
1000                 arg = "@{-1}";
1001
1002         if (get_oid_mb(arg, rev)) {
1003                 /*
1004                  * Either case (3) or (4), with <something> not being
1005                  * a commit, or an attempt to use case (1) with an
1006                  * invalid ref.
1007                  *
1008                  * It's likely an error, but we need to find out if
1009                  * we should auto-create the branch, case (3).(b).
1010                  */
1011                 int recover_with_dwim = dwim_new_local_branch_ok;
1012
1013                 if (!has_dash_dash &&
1014                     (check_filename(opts->prefix, arg) || !no_wildcard(arg)))
1015                         recover_with_dwim = 0;
1016                 /*
1017                  * Accept "git checkout foo" and "git checkout foo --"
1018                  * as candidates for dwim.
1019                  */
1020                 if (!(argc == 1 && !has_dash_dash) &&
1021                     !(argc == 2 && has_dash_dash))
1022                         recover_with_dwim = 0;
1023
1024                 if (recover_with_dwim) {
1025                         const char *remote = unique_tracking_name(arg, rev);
1026                         if (remote) {
1027                                 *new_branch = arg;
1028                                 arg = remote;
1029                                 /* DWIMmed to create local branch, case (3).(b) */
1030                         } else {
1031                                 recover_with_dwim = 0;
1032                         }
1033                 }
1034
1035                 if (!recover_with_dwim) {
1036                         if (has_dash_dash)
1037                                 die(_("invalid reference: %s"), arg);
1038                         return argcount;
1039                 }
1040         }
1041
1042         /* we can't end up being in (2) anymore, eat the argument */
1043         argcount++;
1044         argv++;
1045         argc--;
1046
1047         new->name = arg;
1048         setup_branch_path(new);
1049
1050         if (!check_refname_format(new->path, 0) &&
1051             !read_ref(new->path, branch_rev.hash))
1052                 oidcpy(rev, &branch_rev);
1053         else
1054                 new->path = NULL; /* not an existing branch */
1055
1056         new->commit = lookup_commit_reference_gently(rev, 1);
1057         if (!new->commit) {
1058                 /* not a commit */
1059                 *source_tree = parse_tree_indirect(rev);
1060         } else {
1061                 parse_commit_or_die(new->commit);
1062                 *source_tree = new->commit->tree;
1063         }
1064
1065         if (!*source_tree)                   /* case (1): want a tree */
1066                 die(_("reference is not a tree: %s"), arg);
1067         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1068                 /*
1069                  * Do not complain the most common case
1070                  *      git checkout branch
1071                  * even if there happen to be a file called 'branch';
1072                  * it would be extremely annoying.
1073                  */
1074                 if (argc)
1075                         verify_non_filename(opts->prefix, arg);
1076         } else {
1077                 argcount++;
1078                 argv++;
1079                 argc--;
1080         }
1081
1082         return argcount;
1083 }
1084
1085 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1086 {
1087         int status;
1088         struct strbuf branch_ref = STRBUF_INIT;
1089
1090         if (!opts->new_branch)
1091                 die(_("You are on a branch yet to be born"));
1092         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1093         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1094         strbuf_release(&branch_ref);
1095         if (!opts->quiet)
1096                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1097                         opts->new_branch);
1098         return status;
1099 }
1100
1101 static int checkout_branch(struct checkout_opts *opts,
1102                            struct branch_info *new)
1103 {
1104         if (opts->pathspec.nr)
1105                 die(_("paths cannot be used with switching branches"));
1106
1107         if (opts->patch_mode)
1108                 die(_("'%s' cannot be used with switching branches"),
1109                     "--patch");
1110
1111         if (opts->writeout_stage)
1112                 die(_("'%s' cannot be used with switching branches"),
1113                     "--ours/--theirs");
1114
1115         if (opts->force && opts->merge)
1116                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1117
1118         if (opts->force_detach && opts->new_branch)
1119                 die(_("'%s' cannot be used with '%s'"),
1120                     "--detach", "-b/-B/--orphan");
1121
1122         if (opts->new_orphan_branch) {
1123                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1124                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1125         } else if (opts->force_detach) {
1126                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1127                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1128         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1129                 opts->track = git_branch_track;
1130
1131         if (new->name && !new->commit)
1132                 die(_("Cannot switch branch to a non-commit '%s'"),
1133                     new->name);
1134
1135         if (new->path && !opts->force_detach && !opts->new_branch &&
1136             !opts->ignore_other_worktrees) {
1137                 struct object_id oid;
1138                 int flag;
1139                 char *head_ref = resolve_refdup("HEAD", 0, oid.hash, &flag);
1140                 if (head_ref &&
1141                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
1142                         die_if_checked_out(new->path, 1);
1143                 free(head_ref);
1144         }
1145
1146         if (!new->commit && opts->new_branch) {
1147                 struct object_id rev;
1148                 int flag;
1149
1150                 if (!read_ref_full("HEAD", 0, rev.hash, &flag) &&
1151                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1152                         return switch_unborn_to_new_branch(opts);
1153         }
1154         return switch_branches(opts, new);
1155 }
1156
1157 int cmd_checkout(int argc, const char **argv, const char *prefix)
1158 {
1159         struct checkout_opts opts;
1160         struct branch_info new;
1161         char *conflict_style = NULL;
1162         int dwim_new_local_branch = 1;
1163         struct option options[] = {
1164                 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1165                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1166                            N_("create and checkout a new branch")),
1167                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1168                            N_("create/reset and checkout a branch")),
1169                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1170                 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1171                 OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
1172                         BRANCH_TRACK_EXPLICIT),
1173                 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1174                 OPT_SET_INT('2', "ours", &opts.writeout_stage, N_("checkout our version for unmerged files"),
1175                             2),
1176                 OPT_SET_INT('3', "theirs", &opts.writeout_stage, N_("checkout their version for unmerged files"),
1177                             3),
1178                 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)")),
1179                 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1180                 OPT_BOOL(0, "overwrite-ignore", &opts.overwrite_ignore, N_("update ignored files (default)")),
1181                 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1182                            N_("conflict style (merge or diff3)")),
1183                 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1184                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1185                          N_("do not limit pathspecs to sparse entries only")),
1186                 OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
1187                                 N_("second guess 'git checkout <no-such-branch>'")),
1188                 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1189                          N_("do not check if another worktree is holding the given ref")),
1190                 { OPTION_CALLBACK, 0, "recurse-submodules", &recurse_submodules,
1191                             "checkout", "control recursive updating of submodules",
1192                             PARSE_OPT_OPTARG, option_parse_recurse_submodules },
1193                 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1194                 OPT_END(),
1195         };
1196
1197         memset(&opts, 0, sizeof(opts));
1198         memset(&new, 0, sizeof(new));
1199         opts.overwrite_ignore = 1;
1200         opts.prefix = prefix;
1201         opts.show_progress = -1;
1202
1203         gitmodules_config();
1204         git_config(git_checkout_config, &opts);
1205
1206         opts.track = BRANCH_TRACK_UNSPECIFIED;
1207
1208         argc = parse_options(argc, argv, prefix, options, checkout_usage,
1209                              PARSE_OPT_KEEP_DASHDASH);
1210
1211         if (opts.show_progress < 0) {
1212                 if (opts.quiet)
1213                         opts.show_progress = 0;
1214                 else
1215                         opts.show_progress = isatty(2);
1216         }
1217
1218         if (conflict_style) {
1219                 opts.merge = 1; /* implied */
1220                 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1221         }
1222
1223         if (recurse_submodules != RECURSE_SUBMODULES_OFF) {
1224                 git_config(submodule_config, NULL);
1225                 if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
1226                         set_config_update_recurse_submodules(recurse_submodules);
1227         }
1228
1229         if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1230                 die(_("-b, -B and --orphan are mutually exclusive"));
1231
1232         /*
1233          * From here on, new_branch will contain the branch to be checked out,
1234          * and new_branch_force and new_orphan_branch will tell us which one of
1235          * -b/-B/--orphan is being used.
1236          */
1237         if (opts.new_branch_force)
1238                 opts.new_branch = opts.new_branch_force;
1239
1240         if (opts.new_orphan_branch)
1241                 opts.new_branch = opts.new_orphan_branch;
1242
1243         /* --track without -b/-B/--orphan should DWIM */
1244         if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1245                 const char *argv0 = argv[0];
1246                 if (!argc || !strcmp(argv0, "--"))
1247                         die (_("--track needs a branch name"));
1248                 skip_prefix(argv0, "refs/", &argv0);
1249                 skip_prefix(argv0, "remotes/", &argv0);
1250                 argv0 = strchr(argv0, '/');
1251                 if (!argv0 || !argv0[1])
1252                         die (_("Missing branch name; try -b"));
1253                 opts.new_branch = argv0 + 1;
1254         }
1255
1256         /*
1257          * Extract branch name from command line arguments, so
1258          * all that is left is pathspecs.
1259          *
1260          * Handle
1261          *
1262          *  1) git checkout <tree> -- [<paths>]
1263          *  2) git checkout -- [<paths>]
1264          *  3) git checkout <something> [<paths>]
1265          *
1266          * including "last branch" syntax and DWIM-ery for names of
1267          * remote branches, erroring out for invalid or ambiguous cases.
1268          */
1269         if (argc) {
1270                 struct object_id rev;
1271                 int dwim_ok =
1272                         !opts.patch_mode &&
1273                         dwim_new_local_branch &&
1274                         opts.track == BRANCH_TRACK_UNSPECIFIED &&
1275                         !opts.new_branch;
1276                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1277                                              &new, &opts, &rev);
1278                 argv += n;
1279                 argc -= n;
1280         }
1281
1282         if (argc) {
1283                 parse_pathspec(&opts.pathspec, 0,
1284                                opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1285                                prefix, argv);
1286
1287                 if (!opts.pathspec.nr)
1288                         die(_("invalid path specification"));
1289
1290                 /*
1291                  * Try to give more helpful suggestion.
1292                  * new_branch && argc > 1 will be caught later.
1293                  */
1294                 if (opts.new_branch && argc == 1)
1295                         die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1296                                 argv[0], opts.new_branch);
1297
1298                 if (opts.force_detach)
1299                         die(_("git checkout: --detach does not take a path argument '%s'"),
1300                             argv[0]);
1301
1302                 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1303                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1304                               "checking out of the index."));
1305         }
1306
1307         if (opts.new_branch) {
1308                 struct strbuf buf = STRBUF_INIT;
1309
1310                 opts.branch_exists =
1311                         validate_new_branchname(opts.new_branch, &buf,
1312                                                 !!opts.new_branch_force,
1313                                                 !!opts.new_branch_force);
1314
1315                 strbuf_release(&buf);
1316         }
1317
1318         if (opts.patch_mode || opts.pathspec.nr)
1319                 return checkout_paths(&opts, new.name);
1320         else
1321                 return checkout_branch(&opts, &new);
1322 }