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