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

   1 #include "builtin.h"
   2 #include "config.h"
   3 #include "checkout.h"
   4 #include "lockfile.h"
   5 #include "parse-options.h"
   6 #include "refs.h"
   7 #include "commit.h"
   8 #include "tree.h"
   9 #include "tree-walk.h"
  10 #include "cache-tree.h"
  11 #include "unpack-trees.h"
  12 #include "dir.h"
  13 #include "run-command.h"
  14 #include "merge-recursive.h"
  15 #include "branch.h"
  16 #include "diff.h"
  17 #include "revision.h"
  18 #include "remote.h"
  19 #include "blob.h"
  20 #include "xdiff-interface.h"
  21 #include "ll-merge.h"
  22 #include "resolve-undo.h"
  23 #include "submodule-config.h"
  24 #include "submodule.h"
  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 struct checkout_opts {
  33         int patch_mode;
  34         int quiet;
  35         int merge;
  36         int force;
  37         int force_detach;
  38         int writeout_stage;
  39         int overwrite_ignore;
  40         int ignore_skipworktree;
  41         int ignore_other_worktrees;
  42         int show_progress;
  43
  44         const char *new_branch;
  45         const char *new_branch_force;
  46         const char *new_orphan_branch;
  47         int new_branch_log;
  48         enum branch_track track;
  49         struct diff_options diff_options;
  50
  51         int branch_exists;
  52         const char *prefix;
  53         struct pathspec pathspec;
  54         struct tree *source_tree;
  55 };
  56
  57 static int post_checkout_hook(struct commit *old, struct commit *new,
  58                               int changed)
  59 {
  60         return run_hook_le(NULL, "post-checkout",
  61                            oid_to_hex(old ? &old->object.oid : &null_oid),
  62                            oid_to_hex(new ? &new->object.oid : &null_oid),
  63                            changed ? "1" : "0", NULL);
  64         /* "new" can be NULL when checking out from the index before
  65            a commit exists. */
  66
  67 }
  68
  69 static int update_some(const unsigned char *sha1, struct strbuf *base,
  70                 const char *pathname, unsigned mode, int stage, void *context)
  71 {
  72         int len;
  73         struct cache_entry *ce;
  74         int pos;
  75
  76         if (S_ISDIR(mode))
  77                 return READ_TREE_RECURSIVE;
  78
  79         len = base->len + strlen(pathname);
  80         ce = xcalloc(1, cache_entry_size(len));
  81         hashcpy(ce->oid.hash, sha1);
  82         memcpy(ce->name, base->buf, base->len);
  83         memcpy(ce->name + base->len, pathname, len - base->len);
  84         ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
  85         ce->ce_namelen = len;
  86         ce->ce_mode = create_ce_mode(mode);
  87
  88         /*
  89          * If the entry is the same as the current index, we can leave the old
  90          * entry in place. Whether it is UPTODATE or not, checkout_entry will
  91          * do the right thing.
  92          */
  93         pos = cache_name_pos(ce->name, ce->ce_namelen);
  94         if (pos >= 0) {
  95                 struct cache_entry *old = active_cache[pos];
  96                 if (ce->ce_mode == old->ce_mode &&
  97                     !oidcmp(&ce->oid, &old->oid)) {
  98                         old->ce_flags |= CE_UPDATE;
  99                         free(ce);
 100                         return 0;
 101                 }
 102         }
 103
 104         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 105         return 0;
 106 }
 107
 108 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
 109 {
 110         read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
 111
 112         /* update the index with the given tree's info
 113          * for all args, expanding wildcards, and exit
 114          * with any non-zero return code.
 115          */
 116         return 0;
 117 }
 118
 119 static int skip_same_name(const struct cache_entry *ce, int pos)
 120 {
 121         while (++pos < active_nr &&
 122                !strcmp(active_cache[pos]->name, ce->name))
 123                 ; /* skip */
 124         return pos;
 125 }
 126
 127 static int check_stage(int stage, const struct cache_entry *ce, int pos)
 128 {
 129         while (pos < active_nr &&
 130                !strcmp(active_cache[pos]->name, ce->name)) {
 131                 if (ce_stage(active_cache[pos]) == stage)
 132                         return 0;
 133                 pos++;
 134         }
 135         if (stage == 2)
 136                 return error(_("path '%s' does not have our version"), ce->name);
 137         else
 138                 return error(_("path '%s' does not have their version"), ce->name);
 139 }
 140
 141 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 142 {
 143         unsigned seen = 0;
 144         const char *name = ce->name;
 145
 146         while (pos < active_nr) {
 147                 ce = active_cache[pos];
 148                 if (strcmp(name, ce->name))
 149                         break;
 150                 seen |= (1 << ce_stage(ce));
 151                 pos++;
 152         }
 153         if ((stages & seen) != stages)
 154                 return error(_("path '%s' does not have all necessary versions"),
 155                              name);
 156         return 0;
 157 }
 158
 159 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 160                           const struct checkout *state)
 161 {
 162         while (pos < active_nr &&
 163                !strcmp(active_cache[pos]->name, ce->name)) {
 164                 if (ce_stage(active_cache[pos]) == stage)
 165                         return checkout_entry(active_cache[pos], state, NULL);
 166                 pos++;
 167         }
 168         if (stage == 2)
 169                 return error(_("path '%s' does not have our version"), ce->name);
 170         else
 171                 return error(_("path '%s' does not have their version"), ce->name);
 172 }
 173
 174 static int checkout_merged(int pos, const struct checkout *state)
 175 {
 176         struct cache_entry *ce = active_cache[pos];
 177         const char *path = ce->name;
 178         mmfile_t ancestor, ours, theirs;
 179         int status;
 180         struct object_id oid;
 181         mmbuffer_t result_buf;
 182         struct object_id threeway[3];
 183         unsigned mode = 0;
 184
 185         memset(threeway, 0, sizeof(threeway));
 186         while (pos < active_nr) {
 187                 int stage;
 188                 stage = ce_stage(ce);
 189                 if (!stage || strcmp(path, ce->name))
 190                         break;
 191                 oidcpy(&threeway[stage - 1], &ce->oid);
 192                 if (stage == 2)
 193                         mode = create_ce_mode(ce->ce_mode);
 194                 pos++;
 195                 ce = active_cache[pos];
 196         }
 197         if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 198                 return error(_("path '%s' does not have necessary versions"), path);
 199
 200         read_mmblob(&ancestor, &threeway[0]);
 201         read_mmblob(&ours, &threeway[1]);
 202         read_mmblob(&theirs, &threeway[2]);
 203
 204         /*
 205          * NEEDSWORK: re-create conflicts from merges with
 206          * merge.renormalize set, too
 207          */
 208         status = ll_merge(&result_buf, path, &ancestor, "base",
 209                           &ours, "ours", &theirs, "theirs", NULL);
 210         free(ancestor.ptr);
 211         free(ours.ptr);
 212         free(theirs.ptr);
 213         if (status < 0 || !result_buf.ptr) {
 214                 free(result_buf.ptr);
 215                 return error(_("path '%s': cannot merge"), path);
 216         }
 217
 218         /*
 219          * NEEDSWORK:
 220          * There is absolutely no reason to write this as a blob object
 221          * and create a phony cache entry.  This hack is primarily to get
 222          * to the write_entry() machinery that massages the contents to
 223          * work-tree format and writes out which only allows it for a
 224          * cache entry.  The code in write_entry() needs to be refactored
 225          * to allow us to feed a <buffer, size, mode> instead of a cache
 226          * entry.  Such a refactoring would help merge_recursive as well
 227          * (it also writes the merge result to the object database even
 228          * when it may contain conflicts).
 229          */
 230         if (write_sha1_file(result_buf.ptr, result_buf.size,
 231                             blob_type, oid.hash))
 232                 die(_("Unable to add merge result for '%s'"), path);
 233         free(result_buf.ptr);
 234         ce = make_cache_entry(mode, oid.hash, path, 2, 0);
 235         if (!ce)
 236                 die(_("make_cache_entry failed for path '%s'"), path);
 237         status = checkout_entry(ce, state, NULL);
 238         free(ce);
 239         return status;
 240 }
 241
 242 static int checkout_paths(const struct checkout_opts *opts,
 243                           const char *revision)
 244 {
 245         int pos;
 246         struct checkout state = CHECKOUT_INIT;
 247         static char *ps_matched;
 248         struct object_id rev;
 249         struct commit *head;
 250         int errs = 0;
 251         struct lock_file lock_file = LOCK_INIT;
 252
 253         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 254                 die(_("'%s' cannot be used with updating paths"), "--track");
 255
 256         if (opts->new_branch_log)
 257                 die(_("'%s' cannot be used with updating paths"), "-l");
 258
 259         if (opts->force && opts->patch_mode)
 260                 die(_("'%s' cannot be used with updating paths"), "-f");
 261
 262         if (opts->force_detach)
 263                 die(_("'%s' cannot be used with updating paths"), "--detach");
 264
 265         if (opts->merge && opts->patch_mode)
 266                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 267
 268         if (opts->force && opts->merge)
 269                 die(_("'%s' cannot be used with %s"), "-f", "-m");
 270
 271         if (opts->new_branch)
 272                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 273                     opts->new_branch);
 274
 275         if (opts->patch_mode)
 276                 return run_add_interactive(revision, "--patch=checkout",
 277                                            &opts->pathspec);
 278
 279         hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 280         if (read_cache_preload(&opts->pathspec) < 0)
 281                 return error(_("index file corrupt"));
 282
 283         if (opts->source_tree)
 284                 read_tree_some(opts->source_tree, &opts->pathspec);
 285
 286         ps_matched = xcalloc(opts->pathspec.nr, 1);
 287
 288         /*
 289          * Make sure all pathspecs participated in locating the paths
 290          * to be checked out.
 291          */
 292         for (pos = 0; pos < active_nr; pos++) {
 293                 struct cache_entry *ce = active_cache[pos];
 294                 ce->ce_flags &= ~CE_MATCHED;
 295                 if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 296                         continue;
 297                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 298                         /*
 299                          * "git checkout tree-ish -- path", but this entry
 300                          * is in the original index; it will not be checked
 301                          * out to the working tree and it does not matter
 302                          * if pathspec matched this entry.  We will not do
 303                          * anything to this entry at all.
 304                          */
 305                         continue;
 306                 /*
 307                  * Either this entry came from the tree-ish we are
 308                  * checking the paths out of, or we are checking out
 309                  * of the index.
 310                  *
 311                  * If it comes from the tree-ish, we already know it
 312                  * matches the pathspec and could just stamp
 313                  * CE_MATCHED to it from update_some(). But we still
 314                  * need ps_matched and read_tree_recursive (and
 315                  * eventually tree_entry_interesting) cannot fill
 316                  * ps_matched yet. Once it can, we can avoid calling
 317                  * match_pathspec() for _all_ entries when
 318                  * opts->source_tree != NULL.
 319                  */
 320                 if (ce_path_match(ce, &opts->pathspec, ps_matched))
 321                         ce->ce_flags |= CE_MATCHED;
 322         }
 323
 324         if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
 325                 free(ps_matched);
 326                 return 1;
 327         }
 328         free(ps_matched);
 329
 330         /* "checkout -m path" to recreate conflicted state */
 331         if (opts->merge)
 332                 unmerge_marked_index(&the_index);
 333
 334         /* Any unmerged paths? */
 335         for (pos = 0; pos < active_nr; pos++) {
 336                 const struct cache_entry *ce = active_cache[pos];
 337                 if (ce->ce_flags & CE_MATCHED) {
 338                         if (!ce_stage(ce))
 339                                 continue;
 340                         if (opts->force) {
 341                                 warning(_("path '%s' is unmerged"), ce->name);
 342                         } else if (opts->writeout_stage) {
 343                                 errs |= check_stage(opts->writeout_stage, ce, pos);
 344                         } else if (opts->merge) {
 345                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 346                         } else {
 347                                 errs = 1;
 348                                 error(_("path '%s' is unmerged"), ce->name);
 349                         }
 350                         pos = skip_same_name(ce, pos) - 1;
 351                 }
 352         }
 353         if (errs)
 354                 return 1;
 355
 356         /* Now we are committed to check them out */
 357         state.force = 1;
 358         state.refresh_cache = 1;
 359         state.istate = &the_index;
 360
 361         enable_delayed_checkout(&state);
 362         for (pos = 0; pos < active_nr; pos++) {
 363                 struct cache_entry *ce = active_cache[pos];
 364                 if (ce->ce_flags & CE_MATCHED) {
 365                         if (!ce_stage(ce)) {
 366                                 errs |= checkout_entry(ce, &state, NULL);
 367                                 continue;
 368                         }
 369                         if (opts->writeout_stage)
 370                                 errs |= checkout_stage(opts->writeout_stage, ce, pos, &state);
 371                         else if (opts->merge)
 372                                 errs |= checkout_merged(pos, &state);
 373                         pos = skip_same_name(ce, pos) - 1;
 374                 }
 375         }
 376         errs |= finish_delayed_checkout(&state);
 377
 378         if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 379                 die(_("unable to write new index file"));
 380
 381         read_ref_full("HEAD", 0, &rev, NULL);
 382         head = lookup_commit_reference_gently(&rev, 1);
 383
 384         errs |= post_checkout_hook(head, head, 0);
 385         return errs;
 386 }
 387
 388 static void show_local_changes(struct object *head,
 389                                const struct diff_options *opts)
 390 {
 391         struct rev_info rev;
 392         /* I think we want full paths, even if we're in a subdirectory. */
 393         init_revisions(&rev, NULL);
 394         rev.diffopt.flags = opts->flags;
 395         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 396         diff_setup_done(&rev.diffopt);
 397         add_pending_object(&rev, head, NULL);
 398         run_diff_index(&rev, 0);
 399 }
 400
 401 static void describe_detached_head(const char *msg, struct commit *commit)
 402 {
 403         struct strbuf sb = STRBUF_INIT;
 404
 405         if (!parse_commit(commit))
 406                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 407         if (print_sha1_ellipsis()) {
 408                 fprintf(stderr, "%s %s... %s\n", msg,
 409                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
 410         } else {
 411                 fprintf(stderr, "%s %s %s\n", msg,
 412                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV), sb.buf);
 413         }
 414         strbuf_release(&sb);
 415 }
 416
 417 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 418                       int worktree, int *writeout_error)
 419 {
 420         struct unpack_trees_options opts;
 421         struct tree_desc tree_desc;
 422
 423         memset(&opts, 0, sizeof(opts));
 424         opts.head_idx = -1;
 425         opts.update = worktree;
 426         opts.skip_unmerged = !worktree;
 427         opts.reset = 1;
 428         opts.merge = 1;
 429         opts.fn = oneway_merge;
 430         opts.verbose_update = o->show_progress;
 431         opts.src_index = &the_index;
 432         opts.dst_index = &the_index;
 433         parse_tree(tree);
 434         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 435         switch (unpack_trees(1, &tree_desc, &opts)) {
 436         case -2:
 437                 *writeout_error = 1;
 438                 /*
 439                  * We return 0 nevertheless, as the index is all right
 440                  * and more importantly we have made best efforts to
 441                  * update paths in the work tree, and we cannot revert
 442                  * them.
 443                  */
 444                 /* fallthrough */
 445         case 0:
 446                 return 0;
 447         default:
 448                 return 128;
 449         }
 450 }
 451
 452 struct branch_info {
 453         const char *name; /* The short name used */
 454         const char *path; /* The full name of a real branch */
 455         struct commit *commit; /* The named commit */
 456         /*
 457          * if not null the branch is detached because it's already
 458          * checked out in this checkout
 459          */
 460         char *checkout;
 461 };
 462
 463 static void setup_branch_path(struct branch_info *branch)
 464 {
 465         struct strbuf buf = STRBUF_INIT;
 466
 467         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 468         if (strcmp(buf.buf, branch->name))
 469                 branch->name = xstrdup(buf.buf);
 470         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 471         branch->path = strbuf_detach(&buf, NULL);
 472 }
 473
 474 static int merge_working_tree(const struct checkout_opts *opts,
 475                               struct branch_info *old,
 476                               struct branch_info *new,
 477                               int *writeout_error)
 478 {
 479         int ret;
 480         struct lock_file lock_file = LOCK_INIT;
 481
 482         hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 483         if (read_cache_preload(NULL) < 0)
 484                 return error(_("index file corrupt"));
 485
 486         resolve_undo_clear();
 487         if (opts->force) {
 488                 ret = reset_tree(new->commit->tree, opts, 1, writeout_error);
 489                 if (ret)
 490                         return ret;
 491         } else {
 492                 struct tree_desc trees[2];
 493                 struct tree *tree;
 494                 struct unpack_trees_options topts;
 495
 496                 memset(&topts, 0, sizeof(topts));
 497                 topts.head_idx = -1;
 498                 topts.src_index = &the_index;
 499                 topts.dst_index = &the_index;
 500
 501                 setup_unpack_trees_porcelain(&topts, "checkout");
 502
 503                 refresh_cache(REFRESH_QUIET);
 504
 505                 if (unmerged_cache()) {
 506                         error(_("you need to resolve your current index first"));
 507                         return 1;
 508                 }
 509
 510                 /* 2-way merge to the new branch */
 511                 topts.initial_checkout = is_cache_unborn();
 512                 topts.update = 1;
 513                 topts.merge = 1;
 514                 topts.gently = opts->merge && old->commit;
 515                 topts.verbose_update = opts->show_progress;
 516                 topts.fn = twoway_merge;
 517                 if (opts->overwrite_ignore) {
 518                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 519                         topts.dir->flags |= DIR_SHOW_IGNORED;
 520                         setup_standard_excludes(topts.dir);
 521                 }
 522                 tree = parse_tree_indirect(old->commit ?
 523                                            &old->commit->object.oid :
 524                                            the_hash_algo->empty_tree);
 525                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 526                 tree = parse_tree_indirect(&new->commit->object.oid);
 527                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 528
 529                 ret = unpack_trees(2, trees, &topts);
 530                 if (ret == -1) {
 531                         /*
 532                          * Unpack couldn't do a trivial merge; either
 533                          * give up or do a real merge, depending on
 534                          * whether the merge flag was used.
 535                          */
 536                         struct tree *result;
 537                         struct tree *work;
 538                         struct merge_options o;
 539                         if (!opts->merge)
 540                                 return 1;
 541
 542                         /*
 543                          * Without old->commit, the below is the same as
 544                          * the two-tree unpack we already tried and failed.
 545                          */
 546                         if (!old->commit)
 547                                 return 1;
 548
 549                         /* Do more real merge */
 550
 551                         /*
 552                          * We update the index fully, then write the
 553                          * tree from the index, then merge the new
 554                          * branch with the current tree, with the old
 555                          * branch as the base. Then we reset the index
 556                          * (but not the working tree) to the new
 557                          * branch, leaving the working tree as the
 558                          * merged version, but skipping unmerged
 559                          * entries in the index.
 560                          */
 561
 562                         add_files_to_cache(NULL, NULL, 0);
 563                         /*
 564                          * NEEDSWORK: carrying over local changes
 565                          * when branches have different end-of-line
 566                          * normalization (or clean+smudge rules) is
 567                          * a pain; plumb in an option to set
 568                          * o.renormalize?
 569                          */
 570                         init_merge_options(&o);
 571                         o.verbosity = 0;
 572                         work = write_tree_from_memory(&o);
 573
 574                         ret = reset_tree(new->commit->tree, opts, 1,
 575                                          writeout_error);
 576                         if (ret)
 577                                 return ret;
 578                         o.ancestor = old->name;
 579                         o.branch1 = new->name;
 580                         o.branch2 = "local";
 581                         ret = merge_trees(&o, new->commit->tree, work,
 582                                 old->commit->tree, &result);
 583                         if (ret < 0)
 584                                 exit(128);
 585                         ret = reset_tree(new->commit->tree, opts, 0,
 586                                          writeout_error);
 587                         strbuf_release(&o.obuf);
 588                         if (ret)
 589                                 return ret;
 590                 }
 591         }
 592
 593         if (!active_cache_tree)
 594                 active_cache_tree = cache_tree();
 595
 596         if (!cache_tree_fully_valid(active_cache_tree))
 597                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 598
 599         if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 600                 die(_("unable to write new index file"));
 601
 602         if (!opts->force && !opts->quiet)
 603                 show_local_changes(&new->commit->object, &opts->diff_options);
 604
 605         return 0;
 606 }
 607
 608 static void report_tracking(struct branch_info *new)
 609 {
 610         struct strbuf sb = STRBUF_INIT;
 611         struct branch *branch = branch_get(new->name);
 612
 613         if (!format_tracking_info(branch, &sb))
 614                 return;
 615         fputs(sb.buf, stdout);
 616         strbuf_release(&sb);
 617 }
 618
 619 static void update_refs_for_switch(const struct checkout_opts *opts,
 620                                    struct branch_info *old,
 621                                    struct branch_info *new)
 622 {
 623         struct strbuf msg = STRBUF_INIT;
 624         const char *old_desc, *reflog_msg;
 625         if (opts->new_branch) {
 626                 if (opts->new_orphan_branch) {
 627                         char *refname;
 628
 629                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 630                         if (opts->new_branch_log &&
 631                             !should_autocreate_reflog(refname)) {
 632                                 int ret;
 633                                 struct strbuf err = STRBUF_INIT;
 634
 635                                 ret = safe_create_reflog(refname, 1, &err);
 636                                 if (ret) {
 637                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 638                                                 opts->new_orphan_branch, err.buf);
 639                                         strbuf_release(&err);
 640                                         free(refname);
 641                                         return;
 642                                 }
 643                                 strbuf_release(&err);
 644                         }
 645                         free(refname);
 646                 }
 647                 else
 648                         create_branch(opts->new_branch, new->name,
 649                                       opts->new_branch_force ? 1 : 0,
 650                                       opts->new_branch_force ? 1 : 0,
 651                                       opts->new_branch_log,
 652                                       opts->quiet,
 653                                       opts->track);
 654                 new->name = opts->new_branch;
 655                 setup_branch_path(new);
 656         }
 657
 658         old_desc = old->name;
 659         if (!old_desc && old->commit)
 660                 old_desc = oid_to_hex(&old->commit->object.oid);
 661
 662         reflog_msg = getenv("GIT_REFLOG_ACTION");
 663         if (!reflog_msg)
 664                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 665                         old_desc ? old_desc : "(invalid)", new->name);
 666         else
 667                 strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
 668
 669         if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
 670                 /* Nothing to do. */
 671         } else if (opts->force_detach || !new->path) {  /* No longer on any branch. */
 672                 update_ref(msg.buf, "HEAD", &new->commit->object.oid, NULL,
 673                            REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
 674                 if (!opts->quiet) {
 675                         if (old->path &&
 676                             advice_detached_head && !opts->force_detach)
 677                                 detach_advice(new->name);
 678                         describe_detached_head(_("HEAD is now at"), new->commit);
 679                 }
 680         } else if (new->path) { /* Switch branches. */
 681                 if (create_symref("HEAD", new->path, msg.buf) < 0)
 682                         die(_("unable to update HEAD"));
 683                 if (!opts->quiet) {
 684                         if (old->path && !strcmp(new->path, old->path)) {
 685                                 if (opts->new_branch_force)
 686                                         fprintf(stderr, _("Reset branch '%s'\n"),
 687                                                 new->name);
 688                                 else
 689                                         fprintf(stderr, _("Already on '%s'\n"),
 690                                                 new->name);
 691                         } else if (opts->new_branch) {
 692                                 if (opts->branch_exists)
 693                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new->name);
 694                                 else
 695                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new->name);
 696                         } else {
 697                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 698                                         new->name);
 699                         }
 700                 }
 701                 if (old->path && old->name) {
 702                         if (!ref_exists(old->path) && reflog_exists(old->path))
 703                                 delete_reflog(old->path);
 704                 }
 705         }
 706         remove_branch_state();
 707         strbuf_release(&msg);
 708         if (!opts->quiet &&
 709             (new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
 710                 report_tracking(new);
 711 }
 712
 713 static int add_pending_uninteresting_ref(const char *refname,
 714                                          const struct object_id *oid,
 715                                          int flags, void *cb_data)
 716 {
 717         add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 718         return 0;
 719 }
 720
 721 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 722 {
 723         strbuf_addstr(sb, "  ");
 724         strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
 725         strbuf_addch(sb, ' ');
 726         if (!parse_commit(commit))
 727                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 728         strbuf_addch(sb, '\n');
 729 }
 730
 731 #define ORPHAN_CUTOFF 4
 732 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 733 {
 734         struct commit *c, *last = NULL;
 735         struct strbuf sb = STRBUF_INIT;
 736         int lost = 0;
 737         while ((c = get_revision(revs)) != NULL) {
 738                 if (lost < ORPHAN_CUTOFF)
 739                         describe_one_orphan(&sb, c);
 740                 last = c;
 741                 lost++;
 742         }
 743         if (ORPHAN_CUTOFF < lost) {
 744                 int more = lost - ORPHAN_CUTOFF;
 745                 if (more == 1)
 746                         describe_one_orphan(&sb, last);
 747                 else
 748                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 749         }
 750
 751         fprintf(stderr,
 752                 Q_(
 753                 /* The singular version */
 754                 "Warning: you are leaving %d commit behind, "
 755                 "not connected to\n"
 756                 "any of your branches:\n\n"
 757                 "%s\n",
 758                 /* The plural version */
 759                 "Warning: you are leaving %d commits behind, "
 760                 "not connected to\n"
 761                 "any of your branches:\n\n"
 762                 "%s\n",
 763                 /* Give ngettext() the count */
 764                 lost),
 765                 lost,
 766                 sb.buf);
 767         strbuf_release(&sb);
 768
 769         if (advice_detached_head)
 770                 fprintf(stderr,
 771                         Q_(
 772                         /* The singular version */
 773                         "If you want to keep it by creating a new branch, "
 774                         "this may be a good time\nto do so with:\n\n"
 775                         " git branch <new-branch-name> %s\n\n",
 776                         /* The plural version */
 777                         "If you want to keep them by creating a new branch, "
 778                         "this may be a good time\nto do so with:\n\n"
 779                         " git branch <new-branch-name> %s\n\n",
 780                         /* Give ngettext() the count */
 781                         lost),
 782                         find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
 783 }
 784
 785 /*
 786  * We are about to leave commit that was at the tip of a detached
 787  * HEAD.  If it is not reachable from any ref, this is the last chance
 788  * for the user to do so without resorting to reflog.
 789  */
 790 static void orphaned_commit_warning(struct commit *old, struct commit *new)
 791 {
 792         struct rev_info revs;
 793         struct object *object = &old->object;
 794
 795         init_revisions(&revs, NULL);
 796         setup_revisions(0, NULL, &revs, NULL);
 797
 798         object->flags &= ~UNINTERESTING;
 799         add_pending_object(&revs, object, oid_to_hex(&object->oid));
 800
 801         for_each_ref(add_pending_uninteresting_ref, &revs);
 802         add_pending_oid(&revs, "HEAD", &new->object.oid, UNINTERESTING);
 803
 804         if (prepare_revision_walk(&revs))
 805                 die(_("internal error in revision walk"));
 806         if (!(old->object.flags & UNINTERESTING))
 807                 suggest_reattach(old, &revs);
 808         else
 809                 describe_detached_head(_("Previous HEAD position was"), old);
 810
 811         /* Clean up objects used, as they will be reused. */
 812         clear_commit_marks_all(ALL_REV_FLAGS);
 813 }
 814
 815 static int switch_branches(const struct checkout_opts *opts,
 816                            struct branch_info *new)
 817 {
 818         int ret = 0;
 819         struct branch_info old;
 820         void *path_to_free;
 821         struct object_id rev;
 822         int flag, writeout_error = 0;
 823         memset(&old, 0, sizeof(old));
 824         old.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
 825         if (old.path)
 826                 old.commit = lookup_commit_reference_gently(&rev, 1);
 827         if (!(flag & REF_ISSYMREF))
 828                 old.path = NULL;
 829
 830         if (old.path)
 831                 skip_prefix(old.path, "refs/heads/", &old.name);
 832
 833         if (!new->name) {
 834                 new->name = "HEAD";
 835                 new->commit = old.commit;
 836                 if (!new->commit)
 837                         die(_("You are on a branch yet to be born"));
 838                 parse_commit_or_die(new->commit);
 839         }
 840
 841         ret = merge_working_tree(opts, &old, new, &writeout_error);
 842         if (ret) {
 843                 free(path_to_free);
 844                 return ret;
 845         }
 846
 847         if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
 848                 orphaned_commit_warning(old.commit, new->commit);
 849
 850         update_refs_for_switch(opts, &old, new);
 851
 852         ret = post_checkout_hook(old.commit, new->commit, 1);
 853         free(path_to_free);
 854         return ret || writeout_error;
 855 }
 856
 857 static int git_checkout_config(const char *var, const char *value, void *cb)
 858 {
 859         if (!strcmp(var, "diff.ignoresubmodules")) {
 860                 struct checkout_opts *opts = cb;
 861                 handle_ignore_submodules_arg(&opts->diff_options, value);
 862                 return 0;
 863         }
 864
 865         if (starts_with(var, "submodule."))
 866                 return git_default_submodule_config(var, value, NULL);
 867
 868         return git_xmerge_config(var, value, NULL);
 869 }
 870
 871 static int parse_branchname_arg(int argc, const char **argv,
 872                                 int dwim_new_local_branch_ok,
 873                                 struct branch_info *new,
 874                                 struct checkout_opts *opts,
 875                                 struct object_id *rev)
 876 {
 877         struct tree **source_tree = &opts->source_tree;
 878         const char **new_branch = &opts->new_branch;
 879         int argcount = 0;
 880         struct object_id branch_rev;
 881         const char *arg;
 882         int dash_dash_pos;
 883         int has_dash_dash = 0;
 884         int i;
 885
 886         /*
 887          * case 1: git checkout <ref> -- [<paths>]
 888          *
 889          *   <ref> must be a valid tree, everything after the '--' must be
 890          *   a path.
 891          *
 892          * case 2: git checkout -- [<paths>]
 893          *
 894          *   everything after the '--' must be paths.
 895          *
 896          * case 3: git checkout <something> [--]
 897          *
 898          *   (a) If <something> is a commit, that is to
 899          *       switch to the branch or detach HEAD at it.  As a special case,
 900          *       if <something> is A...B (missing A or B means HEAD but you can
 901          *       omit at most one side), and if there is a unique merge base
 902          *       between A and B, A...B names that merge base.
 903          *
 904          *   (b) If <something> is _not_ a commit, either "--" is present
 905          *       or <something> is not a path, no -t or -b was given, and
 906          *       and there is a tracking branch whose name is <something>
 907          *       in one and only one remote, then this is a short-hand to
 908          *       fork local <something> from that remote-tracking branch.
 909          *
 910          *   (c) Otherwise, if "--" is present, treat it like case (1).
 911          *
 912          *   (d) Otherwise :
 913          *       - if it's a reference, treat it like case (1)
 914          *       - else if it's a path, treat it like case (2)
 915          *       - else: fail.
 916          *
 917          * case 4: git checkout <something> <paths>
 918          *
 919          *   The first argument must not be ambiguous.
 920          *   - If it's *only* a reference, treat it like case (1).
 921          *   - If it's only a path, treat it like case (2).
 922          *   - else: fail.
 923          *
 924          */
 925         if (!argc)
 926                 return 0;
 927
 928         arg = argv[0];
 929         dash_dash_pos = -1;
 930         for (i = 0; i < argc; i++) {
 931                 if (!strcmp(argv[i], "--")) {
 932                         dash_dash_pos = i;
 933                         break;
 934                 }
 935         }
 936         if (dash_dash_pos == 0)
 937                 return 1; /* case (2) */
 938         else if (dash_dash_pos == 1)
 939                 has_dash_dash = 1; /* case (3) or (1) */
 940         else if (dash_dash_pos >= 2)
 941                 die(_("only one reference expected, %d given."), dash_dash_pos);
 942
 943         if (!strcmp(arg, "-"))
 944                 arg = "@{-1}";
 945
 946         if (get_oid_mb(arg, rev)) {
 947                 /*
 948                  * Either case (3) or (4), with <something> not being
 949                  * a commit, or an attempt to use case (1) with an
 950                  * invalid ref.
 951                  *
 952                  * It's likely an error, but we need to find out if
 953                  * we should auto-create the branch, case (3).(b).
 954                  */
 955                 int recover_with_dwim = dwim_new_local_branch_ok;
 956
 957                 if (!has_dash_dash &&
 958                     (check_filename(opts->prefix, arg) || !no_wildcard(arg)))
 959                         recover_with_dwim = 0;
 960                 /*
 961                  * Accept "git checkout foo" and "git checkout foo --"
 962                  * as candidates for dwim.
 963                  */
 964                 if (!(argc == 1 && !has_dash_dash) &&
 965                     !(argc == 2 && has_dash_dash))
 966                         recover_with_dwim = 0;
 967
 968                 if (recover_with_dwim) {
 969                         const char *remote = unique_tracking_name(arg, rev);
 970                         if (remote) {
 971                                 *new_branch = arg;
 972                                 arg = remote;
 973                                 /* DWIMmed to create local branch, case (3).(b) */
 974                         } else {
 975                                 recover_with_dwim = 0;
 976                         }
 977                 }
 978
 979                 if (!recover_with_dwim) {
 980                         if (has_dash_dash)
 981                                 die(_("invalid reference: %s"), arg);
 982                         return argcount;
 983                 }
 984         }
 985
 986         /* we can't end up being in (2) anymore, eat the argument */
 987         argcount++;
 988         argv++;
 989         argc--;
 990
 991         new->name = arg;
 992         setup_branch_path(new);
 993
 994         if (!check_refname_format(new->path, 0) &&
 995             !read_ref(new->path, &branch_rev))
 996                 oidcpy(rev, &branch_rev);
 997         else
 998                 new->path = NULL; /* not an existing branch */
 999
1000         new->commit = lookup_commit_reference_gently(rev, 1);
1001         if (!new->commit) {
1002                 /* not a commit */
1003                 *source_tree = parse_tree_indirect(rev);
1004         } else {
1005                 parse_commit_or_die(new->commit);
1006                 *source_tree = new->commit->tree;
1007         }
1008
1009         if (!*source_tree)                   /* case (1): want a tree */
1010                 die(_("reference is not a tree: %s"), arg);
1011         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1012                 /*
1013                  * Do not complain the most common case
1014                  *      git checkout branch
1015                  * even if there happen to be a file called 'branch';
1016                  * it would be extremely annoying.
1017                  */
1018                 if (argc)
1019                         verify_non_filename(opts->prefix, arg);
1020         } else {
1021                 argcount++;
1022                 argv++;
1023                 argc--;
1024         }
1025
1026         return argcount;
1027 }
1028
1029 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1030 {
1031         int status;
1032         struct strbuf branch_ref = STRBUF_INIT;
1033
1034         if (!opts->new_branch)
1035                 die(_("You are on a branch yet to be born"));
1036         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1037         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1038         strbuf_release(&branch_ref);
1039         if (!opts->quiet)
1040                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1041                         opts->new_branch);
1042         return status;
1043 }
1044
1045 static int checkout_branch(struct checkout_opts *opts,
1046                            struct branch_info *new)
1047 {
1048         if (opts->pathspec.nr)
1049                 die(_("paths cannot be used with switching branches"));
1050
1051         if (opts->patch_mode)
1052                 die(_("'%s' cannot be used with switching branches"),
1053                     "--patch");
1054
1055         if (opts->writeout_stage)
1056                 die(_("'%s' cannot be used with switching branches"),
1057                     "--ours/--theirs");
1058
1059         if (opts->force && opts->merge)
1060                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1061
1062         if (opts->force_detach && opts->new_branch)
1063                 die(_("'%s' cannot be used with '%s'"),
1064                     "--detach", "-b/-B/--orphan");
1065
1066         if (opts->new_orphan_branch) {
1067                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1068                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1069         } else if (opts->force_detach) {
1070                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1071                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1072         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1073                 opts->track = git_branch_track;
1074
1075         if (new->name && !new->commit)
1076                 die(_("Cannot switch branch to a non-commit '%s'"),
1077                     new->name);
1078
1079         if (new->path && !opts->force_detach && !opts->new_branch &&
1080             !opts->ignore_other_worktrees) {
1081                 int flag;
1082                 char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
1083                 if (head_ref &&
1084                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
1085                         die_if_checked_out(new->path, 1);
1086                 free(head_ref);
1087         }
1088
1089         if (!new->commit && opts->new_branch) {
1090                 struct object_id rev;
1091                 int flag;
1092
1093                 if (!read_ref_full("HEAD", 0, &rev, &flag) &&
1094                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1095                         return switch_unborn_to_new_branch(opts);
1096         }
1097         return switch_branches(opts, new);
1098 }
1099
1100 int cmd_checkout(int argc, const char **argv, const char *prefix)
1101 {
1102         struct checkout_opts opts;
1103         struct branch_info new;
1104         char *conflict_style = NULL;
1105         int dwim_new_local_branch = 1;
1106         struct option options[] = {
1107                 OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
1108                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1109                            N_("create and checkout a new branch")),
1110                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1111                            N_("create/reset and checkout a branch")),
1112                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1113                 OPT_BOOL(0, "detach", &opts.force_detach, N_("detach HEAD at named commit")),
1114                 OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
1115                         BRANCH_TRACK_EXPLICIT),
1116                 OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1117                 OPT_SET_INT('2', "ours", &opts.writeout_stage, N_("checkout our version for unmerged files"),
1118                             2),
1119                 OPT_SET_INT('3', "theirs", &opts.writeout_stage, N_("checkout their version for unmerged files"),
1120                             3),
1121                 OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)")),
1122                 OPT_BOOL('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
1123                 OPT_BOOL(0, "overwrite-ignore", &opts.overwrite_ignore, N_("update ignored files (default)")),
1124                 OPT_STRING(0, "conflict", &conflict_style, N_("style"),
1125                            N_("conflict style (merge or diff3)")),
1126                 OPT_BOOL('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
1127                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts.ignore_skipworktree,
1128                          N_("do not limit pathspecs to sparse entries only")),
1129                 OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
1130                                 N_("second guess 'git checkout <no-such-branch>'")),
1131                 OPT_BOOL(0, "ignore-other-worktrees", &opts.ignore_other_worktrees,
1132                          N_("do not check if another worktree is holding the given ref")),
1133                 { OPTION_CALLBACK, 0, "recurse-submodules", NULL,
1134                             "checkout", "control recursive updating of submodules",
1135                             PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
1136                 OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
1137                 OPT_END(),
1138         };
1139
1140         memset(&opts, 0, sizeof(opts));
1141         memset(&new, 0, sizeof(new));
1142         opts.overwrite_ignore = 1;
1143         opts.prefix = prefix;
1144         opts.show_progress = -1;
1145
1146         git_config(git_checkout_config, &opts);
1147
1148         opts.track = BRANCH_TRACK_UNSPECIFIED;
1149
1150         argc = parse_options(argc, argv, prefix, options, checkout_usage,
1151                              PARSE_OPT_KEEP_DASHDASH);
1152
1153         if (opts.show_progress < 0) {
1154                 if (opts.quiet)
1155                         opts.show_progress = 0;
1156                 else
1157                         opts.show_progress = isatty(2);
1158         }
1159
1160         if (conflict_style) {
1161                 opts.merge = 1; /* implied */
1162                 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
1163         }
1164
1165         if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
1166                 die(_("-b, -B and --orphan are mutually exclusive"));
1167
1168         /*
1169          * From here on, new_branch will contain the branch to be checked out,
1170          * and new_branch_force and new_orphan_branch will tell us which one of
1171          * -b/-B/--orphan is being used.
1172          */
1173         if (opts.new_branch_force)
1174                 opts.new_branch = opts.new_branch_force;
1175
1176         if (opts.new_orphan_branch)
1177                 opts.new_branch = opts.new_orphan_branch;
1178
1179         /* --track without -b/-B/--orphan should DWIM */
1180         if (opts.track != BRANCH_TRACK_UNSPECIFIED && !opts.new_branch) {
1181                 const char *argv0 = argv[0];
1182                 if (!argc || !strcmp(argv0, "--"))
1183                         die (_("--track needs a branch name"));
1184                 skip_prefix(argv0, "refs/", &argv0);
1185                 skip_prefix(argv0, "remotes/", &argv0);
1186                 argv0 = strchr(argv0, '/');
1187                 if (!argv0 || !argv0[1])
1188                         die (_("Missing branch name; try -b"));
1189                 opts.new_branch = argv0 + 1;
1190         }
1191
1192         /*
1193          * Extract branch name from command line arguments, so
1194          * all that is left is pathspecs.
1195          *
1196          * Handle
1197          *
1198          *  1) git checkout <tree> -- [<paths>]
1199          *  2) git checkout -- [<paths>]
1200          *  3) git checkout <something> [<paths>]
1201          *
1202          * including "last branch" syntax and DWIM-ery for names of
1203          * remote branches, erroring out for invalid or ambiguous cases.
1204          */
1205         if (argc) {
1206                 struct object_id rev;
1207                 int dwim_ok =
1208                         !opts.patch_mode &&
1209                         dwim_new_local_branch &&
1210                         opts.track == BRANCH_TRACK_UNSPECIFIED &&
1211                         !opts.new_branch;
1212                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1213                                              &new, &opts, &rev);
1214                 argv += n;
1215                 argc -= n;
1216         }
1217
1218         if (argc) {
1219                 parse_pathspec(&opts.pathspec, 0,
1220                                opts.patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1221                                prefix, argv);
1222
1223                 if (!opts.pathspec.nr)
1224                         die(_("invalid path specification"));
1225
1226                 /*
1227                  * Try to give more helpful suggestion.
1228                  * new_branch && argc > 1 will be caught later.
1229                  */
1230                 if (opts.new_branch && argc == 1)
1231                         die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1232                                 argv[0], opts.new_branch);
1233
1234                 if (opts.force_detach)
1235                         die(_("git checkout: --detach does not take a path argument '%s'"),
1236                             argv[0]);
1237
1238                 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
1239                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1240                               "checking out of the index."));
1241         }
1242
1243         if (opts.new_branch) {
1244                 struct strbuf buf = STRBUF_INIT;
1245
1246                 if (opts.new_branch_force)
1247                         opts.branch_exists = validate_branchname(opts.new_branch, &buf);
1248                 else
1249                         opts.branch_exists =
1250                                 validate_new_branchname(opts.new_branch, &buf, 0);
1251                 strbuf_release(&buf);
1252         }
1253
1254         UNLEAK(opts);
1255         if (opts.patch_mode || opts.pathspec.nr)
1256                 return checkout_paths(&opts, new.name);
1257         else
1258                 return checkout_branch(&opts, &new);
1259 }