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         ce = make_cache_entry(mode, oid.hash, path, 2, 0);
 251         if (!ce)
 252                 die(_("make_cache_entry failed for path '%s'"), path);
 253         status = checkout_entry(ce, state, NULL);
 254         free(ce);
 255         return status;
 256 }
 257
 258 static int checkout_paths(const struct checkout_opts *opts,
 259                           const char *revision)
 260 {
 261         int pos;
 262         struct checkout state = CHECKOUT_INIT;
 263         static char *ps_matched;
 264         struct object_id rev;
 265         struct commit *head;
 266         int errs = 0;
 267         struct lock_file *lock_file;
 268
 269         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 270                 die(_("'%s' cannot be used with updating paths"), "--track");
 271
 272         if (opts->new_branch_log)
 273                 die(_("'%s' cannot be used with updating paths"), "-l");
 274
 275         if (opts->force && opts->patch_mode)
 276                 die(_("'%s' cannot be used with updating paths"), "-f");
 277
 278         if (opts->force_detach)
 279                 die(_("'%s' cannot be used with updating paths"), "--detach");
 280
 281         if (opts->merge && opts->patch_mode)
 282                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 283
 284         if (opts->force && opts->merge)
 285                 die(_("'%s' cannot be used with %s"), "-f", "-m");
 286
 287         if (opts->new_branch)
 288                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 289                     opts->new_branch);
 290
 291         if (opts->patch_mode)
 292                 return run_add_interactive(revision, "--patch=checkout",
 293                                            &opts->pathspec);
 294
 295         lock_file = xcalloc(1, sizeof(struct lock_file));
 296
 297         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 298         if (read_cache_preload(&opts->pathspec) < 0)
 299                 return error(_("index file corrupt"));
 300
 301         if (opts->source_tree)
 302                 read_tree_some(opts->source_tree, &opts->pathspec);
 303
 304         ps_matched = xcalloc(opts->pathspec.nr, 1);
 305
 306         /*
 307          * Make sure all pathspecs participated in locating the paths
 308          * to be checked out.
 309          */
 310         for (pos = 0; pos < active_nr; pos++) {
 311                 struct cache_entry *ce = active_cache[pos];
 312                 ce->ce_flags &= ~CE_MATCHED;
 313                 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 314                         continue;
 315                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 316                         /*
 317                          * "git checkout tree-ish -- path", but this entry
 318                          * is in the original index; it will not be checked
 319                          * out to the working tree and it does not matter
 320                          * if pathspec matched this entry.  We will not do
 321                          * anything to this entry at all.
 322                          */
 323                         continue;
 324                 /*
 325                  * Either this entry came from the tree-ish we are
 326                  * checking the paths out of, or we are checking out
 327                  * of the index.
 328                  *
 329                  * If it comes from the tree-ish, we already know it
 330                  * matches the pathspec and could just stamp
 331                  * CE_MATCHED to it from update_some(). But we still
 332                  * need ps_matched and read_tree_recursive (and
 333                  * eventually tree_entry_interesting) cannot fill
 334                  * ps_matched yet. Once it can, we can avoid calling
 335                  * match_pathspec() for _all_ entries when
 336                  * opts->source_tree != NULL.
 337                  */
 338                 if (ce_path_match(ce, &opts->pathspec, ps_matched))
 339                         ce->ce_flags |= CE_MATCHED;
 340         }
 341
 342         if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
 343                 free(ps_matched);
 344                 return 1;
 345         }
 346         free(ps_matched);
 347
 348         /* "checkout -m path" to recreate conflicted state */
 349         if (opts->merge)
 350                 unmerge_marked_index(&the_index);
 351
 352         /* Any unmerged paths? */
 353         for (pos = 0; pos < active_nr; pos++) {
 354                 const struct cache_entry *ce = active_cache[pos];
 355                 if (ce->ce_flags & CE_MATCHED) {
 356                         if (!ce_stage(ce))
 357                                 continue;
 358                         if (opts->force) {
 359                                 warning(_("path '%s' is unmerged"), ce->name);
 360                         } else if (opts->writeout_stage) {
 361                                 errs |= check_stage(opts->writeout_stage, ce, pos);
 362                         } else if (opts->merge) {
 363                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 364                         } else {
 365                                 errs = 1;
 366                                 error(_("path '%s' is unmerged"), ce->name);
 367                         }
 368                         pos = skip_same_name(ce, pos) - 1;
 369                 }
 370         }
 371         if (errs)
 372                 return 1;
 373
 374         /* Now we are committed to check them out */
 375         state.force = 1;
 376         state.refresh_cache = 1;
 377         state.istate = &the_index;
 378         for (pos = 0; pos < active_nr; pos++) {
 379                 struct cache_entry *ce = active_cache[pos];
 380                 if (ce->ce_flags & CE_MATCHED) {
 381                         if (!ce_stage(ce)) {
 382                                 errs |= checkout_entry(ce, &state, NULL);
 383                                 continue;
 384                         }
 385                         if (opts->writeout_stage)
 386                                 errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
 387                         else if (opts->merge)
 388                                 errs |= checkout_merged(pos, &state);
 389                         pos = skip_same_name(ce, pos) - 1;
 390                 }
 391         }
 392
 393         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 394                 die(_("unable to write new index file"));
 395
 396         read_ref_full("HEAD", 0, rev.hash, NULL);
 397         head = lookup_commit_reference_gently(rev.hash, 1);
 398
 399         errs |= post_checkout_hook(head, head, 0);
 400         return errs;
 401 }
 402
 403 static void show_local_changes(struct object *head,
 404                                const struct diff_options *opts)
 405 {
 406         struct rev_info rev;
 407         /* I think we want full paths, even if we're in a subdirectory. */
 408         init_revisions(&rev, NULL);
 409         rev.diffopt.flags = opts->flags;
 410         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 411         diff_setup_done(&rev.diffopt);
 412         add_pending_object(&rev, head, NULL);
 413         run_diff_index(&rev, 0);
 414 }
 415
 416 static void describe_detached_head(const char *msg, struct commit *commit)
 417 {
 418         struct strbuf sb = STRBUF_INIT;
 419         if (!parse_commit(commit))
 420                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 421         fprintf(stderr, "%s %s... %s\n", msg,
 422                 find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
 423         strbuf_release(&sb);
 424 }
 425
 426 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 427                       int worktree, int *writeout_error)
 428 {
 429         struct unpack_trees_options opts;
 430         struct tree_desc tree_desc;
 431
 432         memset(&opts, 0, sizeof(opts));
 433         opts.head_idx = -1;
 434         opts.update = worktree;
 435         opts.skip_unmerged = !worktree;
 436         opts.reset = 1;
 437         opts.merge = 1;
 438         opts.fn = oneway_merge;
 439         opts.verbose_update = o->show_progress;
 440         opts.src_index = &the_index;
 441         opts.dst_index = &the_index;
 442         parse_tree(tree);
 443         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 444         switch (unpack_trees(1, &tree_desc, &opts)) {
 445         case -2:
 446                 *writeout_error = 1;
 447                 /*
 448                  * We return 0 nevertheless, as the index is all right
 449                  * and more importantly we have made best efforts to
 450                  * update paths in the work tree, and we cannot revert
 451                  * them.
 452                  */
 453         case 0:
 454                 return 0;
 455         default:
 456                 return 128;
 457         }
 458 }
 459
 460 struct branch_info {
 461         const char *name; /* The short name used */
 462         const char *path; /* The full name of a real branch */
 463         struct commit *commit; /* The named commit */
 464         /*
 465          * if not null the branch is detached because it's already
 466          * checked out in this checkout
 467          */
 468         char *checkout;
 469 };
 470
 471 static void setup_branch_path(struct branch_info *branch)
 472 {
 473         struct strbuf buf = STRBUF_INIT;
 474
 475         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 476         if (strcmp(buf.buf, branch->name))
 477                 branch->name = xstrdup(buf.buf);
 478         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 479         branch->path = strbuf_detach(&buf, NULL);
 480 }
 481
 482 static int merge_working_tree(const struct checkout_opts *opts,
 483                               struct branch_info *old,
 484                               struct branch_info *new,
 485                               int *writeout_error)
 486 {
 487         int ret;
 488         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 489
 490         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 491         if (read_cache_preload(NULL) < 0)
 492                 return error(_("index file corrupt"));
 493
 494         resolve_undo_clear();
 495         if (opts->force) {
 496                 ret = reset_tree(new->commit->tree, opts, 1, writeout_error);
 497                 if (ret)
 498                         return ret;
 499         } else {
 500                 struct tree_desc trees[2];
 501                 struct tree *tree;
 502                 struct unpack_trees_options topts;
 503
 504                 memset(&topts, 0, sizeof(topts));
 505                 topts.head_idx = -1;
 506                 topts.src_index = &the_index;
 507                 topts.dst_index = &the_index;
 508
 509                 setup_unpack_trees_porcelain(&topts, "checkout");
 510
 511                 refresh_cache(REFRESH_QUIET);
 512
 513                 if (unmerged_cache()) {
 514                         error(_("you need to resolve your current index first"));
 515                         return 1;
 516                 }
 517
 518                 /* 2-way merge to the new branch */
 519                 topts.initial_checkout = is_cache_unborn();
 520                 topts.update = 1;
 521                 topts.merge = 1;
 522                 topts.gently = opts->merge && old->commit;
 523                 topts.verbose_update = opts->show_progress;
 524                 topts.fn = twoway_merge;
 525                 if (opts->overwrite_ignore) {
 526                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 527                         topts.dir->flags |= DIR_SHOW_IGNORED;
 528                         setup_standard_excludes(topts.dir);
 529                 }
 530                 tree = parse_tree_indirect(old->commit ?
 531                                            old->commit->object.oid.hash :
 532                                            EMPTY_TREE_SHA1_BIN);
 533                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 534                 tree = parse_tree_indirect(new->commit->object.oid.hash);
 535                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 536
 537                 ret = unpack_trees(2, trees, &topts);
 538                 if (ret == -1) {
 539                         /*
 540                          * Unpack couldn't do a trivial merge; either
 541                          * give up or do a real merge, depending on
 542                          * whether the merge flag was used.
 543                          */
 544                         struct tree *result;
 545                         struct tree *work;
 546                         struct merge_options o;
 547                         if (!opts->merge)
 548                                 return 1;
 549
 550                         /*
 551                          * Without old->commit, the below is the same as
 552                          * the two-tree unpack we already tried and failed.
 553                          */
 554                         if (!old->commit)
 555                                 return 1;
 556
 557                         /* Do more real merge */
 558
 559                         /*
 560                          * We update the index fully, then write the
 561                          * tree from the index, then merge the new
 562                          * branch with the current tree, with the old
 563                          * branch as the base. Then we reset the index
 564                          * (but not the working tree) to the new
 565                          * branch, leaving the working tree as the
 566                          * merged version, but skipping unmerged
 567                          * entries in the index.
 568                          */
 569
 570                         add_files_to_cache(NULL, NULL, 0);
 571                         /*
 572                          * NEEDSWORK: carrying over local changes
 573                          * when branches have different end-of-line
 574                          * normalization (or clean+smudge rules) is
 575                          * a pain; plumb in an option to set
 576                          * o.renormalize?
 577                          */
 578                         init_merge_options(&o);
 579                         o.verbosity = 0;
 580                         work = write_tree_from_memory(&o);
 581
 582                         ret = reset_tree(new->commit->tree, opts, 1,
 583                                          writeout_error);
 584                         if (ret)
 585                                 return ret;
 586                         o.ancestor = old->name;
 587                         o.branch1 = new->name;
 588                         o.branch2 = "local";
 589                         ret = merge_trees(&o, new->commit->tree, work,
 590                                 old->commit->tree, &result);
 591                         if (ret < 0)
 592                                 exit(128);
 593                         ret = reset_tree(new->commit->tree, opts, 0,
 594                                          writeout_error);
 595                         strbuf_release(&o.obuf);
 596                         if (ret)
 597                                 return ret;
 598                 }
 599         }
 600
 601         if (!active_cache_tree)
 602                 active_cache_tree = cache_tree();
 603
 604         if (!cache_tree_fully_valid(active_cache_tree))
 605                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 606
 607         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 608                 die(_("unable to write new index file"));
 609
 610         if (!opts->force && !opts->quiet)
 611                 show_local_changes(&new->commit->object, &opts->diff_options);
 612
 613         return 0;
 614 }
 615
 616 static void report_tracking(struct branch_info *new)
 617 {
 618         struct strbuf sb = STRBUF_INIT;
 619         struct branch *branch = branch_get(new->name);
 620
 621         if (!format_tracking_info(branch, &sb))
 622                 return;
 623         fputs(sb.buf, stdout);
 624         strbuf_release(&sb);
 625 }
 626
 627 static void update_refs_for_switch(const struct checkout_opts *opts,
 628                                    struct branch_info *old,
 629                                    struct branch_info *new)
 630 {
 631         struct strbuf msg = STRBUF_INIT;
 632         const char *old_desc, *reflog_msg;
 633         if (opts->new_branch) {
 634                 if (opts->new_orphan_branch) {
 635                         char *refname;
 636
 637                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 638                         if (opts->new_branch_log &&
 639                             !should_autocreate_reflog(refname)) {
 640                                 int ret;
 641                                 struct strbuf err = STRBUF_INIT;
 642
 643                                 ret = safe_create_reflog(refname, 1, &err);
 644                                 if (ret) {
 645                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 646                                                 opts->new_orphan_branch, err.buf);
 647                                         strbuf_release(&err);
 648                                         free(refname);
 649                                         return;
 650                                 }
 651                                 strbuf_release(&err);
 652                         }
 653                         free(refname);
 654                 }
 655                 else
 656                         create_branch(opts->new_branch, new->name,
 657                                       opts->new_branch_force ? 1 : 0,
 658                                       opts->new_branch_log,
 659                                       opts->new_branch_force ? 1 : 0,
 660                                       opts->quiet,
 661                                       opts->track);
 662                 new->name = opts->new_branch;
 663                 setup_branch_path(new);
 664         }
 665
 666         old_desc = old->name;
 667         if (!old_desc && old->commit)
 668                 old_desc = oid_to_hex(&old->commit->object.oid);
 669
 670         reflog_msg = getenv("GIT_REFLOG_ACTION");
 671         if (!reflog_msg)
 672                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 673                         old_desc ? old_desc : "(invalid)", new->name);
 674         else
 675                 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
 676
 677         if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
 678                 /* Nothing to do. */
 679         } else if (opts->force_detach || !new->path) {  /* No longer on any branch. */
 680                 update_ref(msg.buf, "HEAD", new->commit->object.oid.hash, NULL,
 681                            REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
 682                 if (!opts->quiet) {
 683                         if (old->path &&
 684                             advice_detached_head && !opts->force_detach)
 685                                 detach_advice(new->name);
 686                         describe_detached_head(_("HEAD is now at"), new->commit);
 687                 }
 688         } else if (new->path) { /* Switch branches. */
 689                 if (create_symref("HEAD", new->path, msg.buf) < 0)
 690                         die(_("unable to update HEAD"));
 691                 if (!opts->quiet) {
 692                         if (old->path && !strcmp(new->path, old->path)) {
 693                                 if (opts->new_branch_force)
 694                                         fprintf(stderr, _("Reset branch '%s'\n"),
 695                                                 new->name);
 696                                 else
 697                                         fprintf(stderr, _("Already on '%s'\n"),
 698                                                 new->name);
 699                         } else if (opts->new_branch) {
 700                                 if (opts->branch_exists)
 701                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new->name);
 702                                 else
 703                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new->name);
 704                         } else {
 705                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 706                                         new->name);
 707                         }
 708                 }
 709                 if (old->path && old->name) {
 710                         if (!ref_exists(old->path) && reflog_exists(old->path))
 711                                 delete_reflog(old->path);
 712                 }
 713         }
 714         remove_branch_state();
 715         strbuf_release(&msg);
 716         if (!opts->quiet &&
 717             (new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
 718                 report_tracking(new);
 719 }
 720
 721 static int add_pending_uninteresting_ref(const char *refname,
 722                                          const struct object_id *oid,
 723                                          int flags, void *cb_data)
 724 {
 725         add_pending_sha1(cb_data, refname, oid->hash, UNINTERESTING);
 726         return 0;
 727 }
 728
 729 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 730 {
 731         strbuf_addstr(sb, "  ");
 732         strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
 733         strbuf_addch(sb, ' ');
 734         if (!parse_commit(commit))
 735                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 736         strbuf_addch(sb, '\n');
 737 }
 738
 739 #define ORPHAN_CUTOFF 4
 740 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 741 {
 742         struct commit *c, *last = NULL;
 743         struct strbuf sb = STRBUF_INIT;
 744         int lost = 0;
 745         while ((c = get_revision(revs)) != NULL) {
 746                 if (lost < ORPHAN_CUTOFF)
 747                         describe_one_orphan(&sb, c);
 748                 last = c;
 749                 lost++;
 750         }
 751         if (ORPHAN_CUTOFF < lost) {
 752                 int more = lost - ORPHAN_CUTOFF;
 753                 if (more == 1)
 754                         describe_one_orphan(&sb, last);
 755                 else
 756                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 757         }
 758
 759         fprintf(stderr,
 760                 Q_(
 761                 /* The singular version */
 762                 "Warning: you are leaving %d commit behind, "
 763                 "not connected to\n"
 764                 "any of your branches:\n\n"
 765                 "%s\n",
 766                 /* The plural version */
 767                 "Warning: you are leaving %d commits behind, "
 768                 "not connected to\n"
 769                 "any of your branches:\n\n"
 770                 "%s\n",
 771                 /* Give ngettext() the count */
 772                 lost),
 773                 lost,
 774                 sb.buf);
 775         strbuf_release(&sb);
 776
 777         if (advice_detached_head)
 778                 fprintf(stderr,
 779                         Q_(
 780                         /* The singular version */
 781                         "If you want to keep it by creating a new branch, "
 782                         "this may be a good time\nto do so with:\n\n"
 783                         " git branch <new-branch-name> %s\n\n",
 784                         /* The plural version */
 785                         "If you want to keep them 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                         /* Give ngettext() the count */
 789                         lost),
 790                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
 791 }
 792
 793 /*
 794  * We are about to leave commit that was at the tip of a detached
 795  * HEAD.  If it is not reachable from any ref, this is the last chance
 796  * for the user to do so without resorting to reflog.
 797  */
 798 static void orphaned_commit_warning(struct commit *old, struct commit *new)
 799 {
 800         struct rev_info revs;
 801         struct object *object = &old->object;
 802         struct object_array refs;
 803
 804         init_revisions(&revs, NULL);
 805         setup_revisions(0, NULL, &revs, NULL);
 806
 807         object->flags &= ~UNINTERESTING;
 808         add_pending_object(&revs, object, oid_to_hex(&object->oid));
 809
 810         for_each_ref(add_pending_uninteresting_ref, &revs);
 811         add_pending_sha1(&revs, "HEAD", new->object.oid.hash, UNINTERESTING);
 812
 813         refs = revs.pending;
 814         revs.leak_pending = 1;
 815
 816         if (prepare_revision_walk(&revs))
 817                 die(_("internal error in revision walk"));
 818         if (!(old->object.flags & UNINTERESTING))
 819                 suggest_reattach(old, &revs);
 820         else
 821                 describe_detached_head(_("Previous HEAD position was"), old);
 822
 823         clear_commit_marks_for_object_array(&refs, ALL_REV_FLAGS);
 824         free(refs.objects);
 825 }
 826
 827 static int switch_branches(const struct checkout_opts *opts,
 828                            struct branch_info *new)
 829 {
 830         int ret = 0;
 831         struct branch_info old;
 832         void *path_to_free;
 833         struct object_id rev;
 834         int flag, writeout_error = 0;
 835         memset(&old, 0, sizeof(old));
 836         old.path = path_to_free = resolve_refdup("HEAD", 0, rev.hash, &flag);
 837         old.commit = lookup_commit_reference_gently(rev.hash, 1);
 838         if (!(flag & REF_ISSYMREF))
 839                 old.path = NULL;
 840
 841         if (old.path)
 842                 skip_prefix(old.path, "refs/heads/", &old.name);
 843
 844         if (!new->name) {
 845                 new->name = "HEAD";
 846                 new->commit = old.commit;
 847                 if (!new->commit)
 848                         die(_("You are on a branch yet to be born"));
 849                 parse_commit_or_die(new->commit);
 850         }
 851
 852         ret = merge_working_tree(opts, &old, new, &writeout_error);
 853         if (ret) {
 854                 free(path_to_free);
 855                 return ret;
 856         }
 857
 858         if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
 859                 orphaned_commit_warning(old.commit, new->commit);
 860
 861         update_refs_for_switch(opts, &old, new);
 862
 863         ret = post_checkout_hook(old.commit, new->commit, 1);
 864         free(path_to_free);
 865         return ret || writeout_error;
 866 }
 867
 868 static int git_checkout_config(const char *var, const char *value, void *cb)
 869 {
 870         if (!strcmp(var, "diff.ignoresubmodules")) {
 871                 struct checkout_opts *opts = cb;
 872                 handle_ignore_submodules_arg(&opts->diff_options, value);
 873                 return 0;
 874         }
 875
 876         if (starts_with(var, "submodule."))
 877                 return parse_submodule_config_option(var, value);
 878
 879         return git_xmerge_config(var, value, NULL);
 880 }
 881
 882 struct tracking_name_data {
 883         /* const */ char *src_ref;
 884         char *dst_ref;
 885         struct object_id *dst_oid;
 886         int unique;
 887 };
 888
 889 static int check_tracking_name(struct remote *remote, void *cb_data)
 890 {
 891         struct tracking_name_data *cb = cb_data;
 892         struct refspec query;
 893         memset(&query, 0, sizeof(struct refspec));
 894         query.src = cb->src_ref;
 895         if (remote_find_tracking(remote, &query) ||
 896             get_oid(query.dst, cb->dst_oid)) {
 897                 free(query.dst);
 898                 return 0;
 899         }
 900         if (cb->dst_ref) {
 901                 free(query.dst);
 902                 cb->unique = 0;
 903                 return 0;
 904         }
 905         cb->dst_ref = query.dst;
 906         return 0;
 907 }
 908
 909 static const char *unique_tracking_name(const char *name, struct object_id *oid)
 910 {
 911         struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
 912         cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 913         cb_data.dst_oid = oid;
 914         for_each_remote(check_tracking_name, &cb_data);
 915         free(cb_data.src_ref);
 916         if (cb_data.unique)
 917                 return cb_data.dst_ref;
 918         free(cb_data.dst_ref);
 919         return NULL;
 920 }
 921
 922 static int parse_branchname_arg(int argc, const char **argv,
 923                                 int dwim_new_local_branch_ok,
 924                                 struct branch_info *new,
 925                                 struct checkout_opts *opts,
 926                                 struct object_id *rev)
 927 {
 928         struct tree **source_tree = &opts->source_tree;
 929         const char **new_branch = &opts->new_branch;
 930         int argcount = 0;
 931         struct object_id branch_rev;
 932         const char *arg;
 933         int dash_dash_pos;
 934         int has_dash_dash = 0;
 935         int i;
 936
 937         /*
 938          * case 1: git checkout <ref> -- [<paths>]
 939          *
 940          *   <ref> must be a valid tree, everything after the '--' must be
 941          *   a path.
 942          *
 943          * case 2: git checkout -- [<paths>]
 944          *
 945          *   everything after the '--' must be paths.
 946          *
 947          * case 3: git checkout <something> [--]
 948          *
 949          *   (a) If <something> is a commit, that is to
 950          *       switch to the branch or detach HEAD at it.  As a special case,
 951          *       if <something> is A...B (missing A or B means HEAD but you can
 952          *       omit at most one side), and if there is a unique merge base
 953          *       between A and B, A...B names that merge base.
 954          *
 955          *   (b) If <something> is _not_ a commit, either "--" is present
 956          *       or <something> is not a path, no -t or -b was given, and
 957          *       and there is a tracking branch whose name is <something>
 958          *       in one and only one remote, then this is a short-hand to
 959          *       fork local <something> from that remote-tracking branch.
 960          *
 961          *   (c) Otherwise, if "--" is present, treat it like case (1).
 962          *
 963          *   (d) Otherwise :
 964          *       - if it's a reference, treat it like case (1)
 965          *       - else if it's a path, treat it like case (2)
 966          *       - else: fail.
 967          *
 968          * case 4: git checkout <something> <paths>
 969          *
 970          *   The first argument must not be ambiguous.
 971          *   - If it's *only* a reference, treat it like case (1).
 972          *   - If it's only a path, treat it like case (2).
 973          *   - else: fail.
 974          *
 975          */
 976         if (!argc)
 977                 return 0;
 978
 979         arg = argv[0];
 980         dash_dash_pos = -1;
 981         for (i = 0; i < argc; i++) {
 982                 if (!strcmp(argv[i], "--")) {
 983                         dash_dash_pos = i;
 984                         break;
 985                 }
 986         }
 987         if (dash_dash_pos == 0)
 988                 return 1; /* case (2) */
 989         else if (dash_dash_pos == 1)
 990                 has_dash_dash = 1; /* case (3) or (1) */
 991         else if (dash_dash_pos >= 2)
 992                 die(_("only one reference expected, %d given."), dash_dash_pos);
 993
 994         if (!strcmp(arg, "-"))
 995                 arg = "@{-1}";
 996
 997         if (get_oid_mb(arg, rev)) {
 998                 /*
 999                  * Either case (3) or (4), with <something> not being
1000                  * a commit, or an attempt to use case (1) with an
1001                  * invalid ref.
1002                  *
1003                  * It's likely an error, but we need to find out if
1004                  * we should auto-create the branch, case (3).(b).
1005                  */
1006                 int recover_with_dwim = dwim_new_local_branch_ok;
1007
1008                 if (!has_dash_dash &&
1009                     (check_filename(opts->prefix, arg) || !no_wildcard(arg)))
1010                         recover_with_dwim = 0;
1011                 /*
1012                  * Accept "git checkout foo" and "git checkout foo --"
1013                  * as candidates for dwim.
1014                  */
1015                 if (!(argc == 1 && !has_dash_dash) &&
1016                     !(argc == 2 && has_dash_dash))
1017                         recover_with_dwim = 0;
1018
1019                 if (recover_with_dwim) {
1020                         const char *remote = unique_tracking_name(arg, rev);
1021                         if (remote) {
1022                                 *new_branch = arg;
1023                                 arg = remote;
1024                                 /* DWIMmed to create local branch, case (3).(b) */
1025                         } else {
1026                                 recover_with_dwim = 0;
1027                         }
1028                 }
1029
1030                 if (!recover_with_dwim) {
1031                         if (has_dash_dash)
1032                                 die(_("invalid reference: %s"), arg);
1033                         return argcount;
1034                 }
1035         }
1036
1037         /* we can't end up being in (2) anymore, eat the argument */
1038         argcount++;
1039         argv++;
1040         argc--;
1041
1042         new->name = arg;
1043         setup_branch_path(new);
1044
1045         if (!check_refname_format(new->path, 0) &&
1046             !read_ref(new->path, branch_rev.hash))
1047                 oidcpy(rev, &branch_rev);
1048         else
1049                 new->path = NULL; /* not an existing branch */
1050
1051         new->commit = lookup_commit_reference_gently(rev->hash, 1);
1052         if (!new->commit) {
1053                 /* not a commit */
1054                 *source_tree = parse_tree_indirect(rev->hash);
1055         } else {
1056                 parse_commit_or_die(new->commit);
1057                 *source_tree = new->commit->tree;
1058         }
1059
1060         if (!*source_tree)                   /* case (1): want a tree */
1061                 die(_("reference is not a tree: %s"), arg);
1062         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1063                 /*
1064                  * Do not complain the most common case
1065                  *      git checkout branch
1066                  * even if there happen to be a file called 'branch';
1067                  * it would be extremely annoying.
1068                  */
1069                 if (argc)
1070                         verify_non_filename(opts->prefix, arg);
1071         } else {
1072                 argcount++;
1073                 argv++;
1074                 argc--;
1075         }
1076
1077         return argcount;
1078 }
1079
1080 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1081 {
1082         int status;
1083         struct strbuf branch_ref = STRBUF_INIT;
1084
1085         if (!opts->new_branch)
1086                 die(_("You are on a branch yet to be born"));
1087         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1088         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1089         strbuf_release(&branch_ref);
1090         if (!opts->quiet)
1091                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1092                         opts->new_branch);
1093         return status;
1094 }
1095
1096 static int checkout_branch(struct checkout_opts *opts,
1097                            struct branch_info *new)
1098 {
1099         if (opts->pathspec.nr)
1100                 die(_("paths cannot be used with switching branches"));
1101
1102         if (opts->patch_mode)
1103                 die(_("'%s' cannot be used with switching branches"),
1104                     "--patch");
1105
1106         if (opts->writeout_stage)
1107                 die(_("'%s' cannot be used with switching branches"),
1108                     "--ours/--theirs");
1109
1110         if (opts->force && opts->merge)
1111                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1112
1113         if (opts->force_detach && opts->new_branch)
1114                 die(_("'%s' cannot be used with '%s'"),
1115                     "--detach", "-b/-B/--orphan");
1116
1117         if (opts->new_orphan_branch) {
1118                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1119                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1120         } else if (opts->force_detach) {
1121                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1122                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1123         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1124                 opts->track = git_branch_track;
1125
1126         if (new->name && !new->commit)
1127                 die(_("Cannot switch branch to a non-commit '%s'"),
1128                     new->name);
1129
1130         if (new->path && !opts->force_detach && !opts->new_branch &&
1131             !opts->ignore_other_worktrees) {
1132                 struct object_id oid;
1133                 int flag;
1134                 char *head_ref = resolve_refdup("HEAD", 0, oid.hash, &flag);
1135                 if (head_ref &&
1136                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
1137                         die_if_checked_out(new->path, 1);
1138                 free(head_ref);
1139         }
1140
1141         if (!new->commit && opts->new_branch) {
1142                 struct object_id rev;
1143                 int flag;
1144
1145                 if (!read_ref_full("HEAD", 0, rev.hash, &flag) &&
1146                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1147                         return switch_unborn_to_new_branch(opts);
1148         }
1149         return switch_branches(opts, new);
1150 }
1151
1152 int cmd_checkout(int argc, const char **argv, const char *prefix)
1153 {
1154         struct checkout_opts opts;
1155         struct branch_info new;
1156         char *conflict_style = NULL;
1157         int dwim_new_local_branch = 1;
1158         struct option options[] = {
1159                 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1160                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1161                            N_("create and checkout a new branch")),
1162                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1163                            N_("create/reset and checkout a branch")),
1164                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1165                 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1166                 OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
1167                         BRANCH_TRACK_EXPLICIT),
1168                 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1169                 OPT_SET_INT('2', "ours", &opts.writeout_stage, N_("checkout our version for unmerged files"),
1170                             2),
1171                 OPT_SET_INT('3', "theirs", &opts.writeout_stage, N_("checkout their version for unmerged files"),
1172                             3),
1173                 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)")),
1174                 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1175                 OPT_BOOL(0, "overwrite-ignore", &opts.overwrite_ignore, N_("update ignored files (default)")),
1176                 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1177                            N_("conflict style (merge or diff3)")),
1178                 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1179                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1180                          N_("do not limit pathspecs to sparse entries only")),
1181                 OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
1182                                 N_("second guess 'git checkout <no-such-branch>'")),
1183                 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1184                          N_("do not check if another worktree is holding the given ref")),
1185                 { OPTION_CALLBACK, 0, "recurse-submodules", &recurse_submodules,
1186                             "checkout", "control recursive updating of submodules",
1187                             PARSE_OPT_OPTARG, option_parse_recurse_submodules },
1188                 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1189                 OPT_END(),
1190         };
1191
1192         memset(&opts, 0, sizeof(opts));
1193         memset(&new, 0, sizeof(new));
1194         opts.overwrite_ignore = 1;
1195         opts.prefix = prefix;
1196         opts.show_progress = -1;
1197
1198         gitmodules_config();
1199         git_config(git_checkout_config, &opts);
1200
1201         opts.track = BRANCH_TRACK_UNSPECIFIED;
1202
1203         argc = parse_options(argc, argv, prefix, options, checkout_usage,
1204                              PARSE_OPT_KEEP_DASHDASH);
1205
1206         if (opts.show_progress < 0) {
1207                 if (opts.quiet)
1208                         opts.show_progress = 0;
1209                 else
1210                         opts.show_progress = isatty(2);
1211         }
1212
1213         if (conflict_style) {
1214                 opts.merge = 1; /* implied */
1215                 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1216         }
1217
1218         if (recurse_submodules != RECURSE_SUBMODULES_OFF) {
1219                 git_config(submodule_config, NULL);
1220                 if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
1221                         set_config_update_recurse_submodules(recurse_submodules);
1222         }
1223
1224         if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1225                 die(_("-b, -B and --orphan are mutually exclusive"));
1226
1227         /*
1228          * From here on, new_branch will contain the branch to be checked out,
1229          * and new_branch_force and new_orphan_branch will tell us which one of
1230          * -b/-B/--orphan is being used.
1231          */
1232         if (opts.new_branch_force)
1233                 opts.new_branch = opts.new_branch_force;
1234
1235         if (opts.new_orphan_branch)
1236                 opts.new_branch = opts.new_orphan_branch;
1237
1238         /* --track without -b/-B/--orphan should DWIM */
1239         if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1240                 const char *argv0 = argv[0];
1241                 if (!argc || !strcmp(argv0, "--"))
1242                         die (_("--track needs a branch name"));
1243                 skip_prefix(argv0, "refs/", &argv0);
1244                 skip_prefix(argv0, "remotes/", &argv0);
1245                 argv0 = strchr(argv0, '/');
1246                 if (!argv0 || !argv0[1])
1247                         die (_("Missing branch name; try -b"));
1248                 opts.new_branch = argv0 + 1;
1249         }
1250
1251         /*
1252          * Extract branch name from command line arguments, so
1253          * all that is left is pathspecs.
1254          *
1255          * Handle
1256          *
1257          *  1) git checkout <tree> -- [<paths>]
1258          *  2) git checkout -- [<paths>]
1259          *  3) git checkout <something> [<paths>]
1260          *
1261          * including "last branch" syntax and DWIM-ery for names of
1262          * remote branches, erroring out for invalid or ambiguous cases.
1263          */
1264         if (argc) {
1265                 struct object_id rev;
1266                 int dwim_ok =
1267                         !opts.patch_mode &&
1268                         dwim_new_local_branch &&
1269                         opts.track == BRANCH_TRACK_UNSPECIFIED &&
1270                         !opts.new_branch;
1271                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1272                                              &new, &opts, &rev);
1273                 argv += n;
1274                 argc -= n;
1275         }
1276
1277         if (argc) {
1278                 parse_pathspec(&opts.pathspec, 0,
1279                                opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1280                                prefix, argv);
1281
1282                 if (!opts.pathspec.nr)
1283                         die(_("invalid path specification"));
1284
1285                 /*
1286                  * Try to give more helpful suggestion.
1287                  * new_branch && argc > 1 will be caught later.
1288                  */
1289                 if (opts.new_branch && argc == 1)
1290                         die(_("Cannot update paths and switch to branch '%s' at the same time.\n"
1291                               "Did you intend to checkout '%s' which can not be resolved as commit?"),
1292                             opts.new_branch, argv[0]);
1293
1294                 if (opts.force_detach)
1295                         die(_("git checkout: --detach does not take a path argument '%s'"),
1296                             argv[0]);
1297
1298                 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1299                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1300                               "checking out of the index."));
1301         }
1302
1303         if (opts.new_branch) {
1304                 struct strbuf buf = STRBUF_INIT;
1305
1306                 opts.branch_exists =
1307                         validate_new_branchname(opts.new_branch, &buf,
1308                                                 !!opts.new_branch_force,
1309                                                 !!opts.new_branch_force);
1310
1311                 strbuf_release(&buf);
1312         }
1313
1314         if (opts.patch_mode || opts.pathspec.nr)
1315                 return checkout_paths(&opts, new.name);
1316         else
1317                 return checkout_branch(&opts, &new);
1318 }