0584dc484d0203866fa9f84fcb6b61409baeeefd
   1#define USE_THE_INDEX_COMPATIBILITY_MACROS
   2#include "builtin.h"
   3#include "advice.h"
   4#include "blob.h"
   5#include "branch.h"
   6#include "cache-tree.h"
   7#include "checkout.h"
   8#include "commit.h"
   9#include "config.h"
  10#include "diff.h"
  11#include "dir.h"
  12#include "ll-merge.h"
  13#include "lockfile.h"
  14#include "merge-recursive.h"
  15#include "object-store.h"
  16#include "parse-options.h"
  17#include "refs.h"
  18#include "remote.h"
  19#include "resolve-undo.h"
  20#include "revision.h"
  21#include "run-command.h"
  22#include "submodule.h"
  23#include "submodule-config.h"
  24#include "tree.h"
  25#include "tree-walk.h"
  26#include "unpack-trees.h"
  27#include "xdiff-interface.h"
  28
  29static int checkout_optimize_new_branch;
  30
  31static const char * const checkout_usage[] = {
  32        N_("git checkout [<options>] <branch>"),
  33        N_("git checkout [<options>] [<branch>] -- <file>..."),
  34        NULL,
  35};
  36
  37static const char * const switch_branch_usage[] = {
  38        N_("git switch [<options>] [<branch>]"),
  39        NULL,
  40};
  41
  42struct checkout_opts {
  43        int patch_mode;
  44        int quiet;
  45        int merge;
  46        int force;
  47        int force_detach;
  48        int writeout_stage;
  49        int overwrite_ignore;
  50        int ignore_skipworktree;
  51        int ignore_other_worktrees;
  52        int show_progress;
  53        int count_checkout_paths;
  54        int overlay_mode;
  55        int no_dwim_new_local_branch;
  56        int discard_changes;
  57        int accept_pathspec;
  58
  59        /*
  60         * If new checkout options are added, skip_merge_working_tree
  61         * should be updated accordingly.
  62         */
  63
  64        const char *new_branch;
  65        const char *new_branch_force;
  66        const char *new_orphan_branch;
  67        int new_branch_log;
  68        enum branch_track track;
  69        struct diff_options diff_options;
  70        char *conflict_style;
  71
  72        int branch_exists;
  73        const char *prefix;
  74        struct pathspec pathspec;
  75        struct tree *source_tree;
  76};
  77
  78static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
  79                              int changed)
  80{
  81        return run_hook_le(NULL, "post-checkout",
  82                           oid_to_hex(old_commit ? &old_commit->object.oid : &null_oid),
  83                           oid_to_hex(new_commit ? &new_commit->object.oid : &null_oid),
  84                           changed ? "1" : "0", NULL);
  85        /* "new_commit" can be NULL when checking out from the index before
  86           a commit exists. */
  87
  88}
  89
  90static int update_some(const struct object_id *oid, struct strbuf *base,
  91                const char *pathname, unsigned mode, int stage, void *context)
  92{
  93        int len;
  94        struct cache_entry *ce;
  95        int pos;
  96
  97        if (S_ISDIR(mode))
  98                return READ_TREE_RECURSIVE;
  99
 100        len = base->len + strlen(pathname);
 101        ce = make_empty_cache_entry(&the_index, len);
 102        oidcpy(&ce->oid, oid);
 103        memcpy(ce->name, base->buf, base->len);
 104        memcpy(ce->name + base->len, pathname, len - base->len);
 105        ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
 106        ce->ce_namelen = len;
 107        ce->ce_mode = create_ce_mode(mode);
 108
 109        /*
 110         * If the entry is the same as the current index, we can leave the old
 111         * entry in place. Whether it is UPTODATE or not, checkout_entry will
 112         * do the right thing.
 113         */
 114        pos = cache_name_pos(ce->name, ce->ce_namelen);
 115        if (pos >= 0) {
 116                struct cache_entry *old = active_cache[pos];
 117                if (ce->ce_mode == old->ce_mode &&
 118                    oideq(&ce->oid, &old->oid)) {
 119                        old->ce_flags |= CE_UPDATE;
 120                        discard_cache_entry(ce);
 121                        return 0;
 122                }
 123        }
 124
 125        add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 126        return 0;
 127}
 128
 129static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
 130{
 131        read_tree_recursive(the_repository, tree, "", 0, 0,
 132                            pathspec, update_some, NULL);
 133
 134        /* update the index with the given tree's info
 135         * for all args, expanding wildcards, and exit
 136         * with any non-zero return code.
 137         */
 138        return 0;
 139}
 140
 141static int skip_same_name(const struct cache_entry *ce, int pos)
 142{
 143        while (++pos < active_nr &&
 144               !strcmp(active_cache[pos]->name, ce->name))
 145                ; /* skip */
 146        return pos;
 147}
 148
 149static int check_stage(int stage, const struct cache_entry *ce, int pos,
 150                       int overlay_mode)
 151{
 152        while (pos < active_nr &&
 153               !strcmp(active_cache[pos]->name, ce->name)) {
 154                if (ce_stage(active_cache[pos]) == stage)
 155                        return 0;
 156                pos++;
 157        }
 158        if (!overlay_mode)
 159                return 0;
 160        if (stage == 2)
 161                return error(_("path '%s' does not have our version"), ce->name);
 162        else
 163                return error(_("path '%s' does not have their version"), ce->name);
 164}
 165
 166static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 167{
 168        unsigned seen = 0;
 169        const char *name = ce->name;
 170
 171        while (pos < active_nr) {
 172                ce = active_cache[pos];
 173                if (strcmp(name, ce->name))
 174                        break;
 175                seen |= (1 << ce_stage(ce));
 176                pos++;
 177        }
 178        if ((stages & seen) != stages)
 179                return error(_("path '%s' does not have all necessary versions"),
 180                             name);
 181        return 0;
 182}
 183
 184static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 185                          const struct checkout *state, int *nr_checkouts,
 186                          int overlay_mode)
 187{
 188        while (pos < active_nr &&
 189               !strcmp(active_cache[pos]->name, ce->name)) {
 190                if (ce_stage(active_cache[pos]) == stage)
 191                        return checkout_entry(active_cache[pos], state,
 192                                              NULL, nr_checkouts);
 193                pos++;
 194        }
 195        if (!overlay_mode) {
 196                unlink_entry(ce);
 197                return 0;
 198        }
 199        if (stage == 2)
 200                return error(_("path '%s' does not have our version"), ce->name);
 201        else
 202                return error(_("path '%s' does not have their version"), ce->name);
 203}
 204
 205static int checkout_merged(int pos, const struct checkout *state, int *nr_checkouts)
 206{
 207        struct cache_entry *ce = active_cache[pos];
 208        const char *path = ce->name;
 209        mmfile_t ancestor, ours, theirs;
 210        int status;
 211        struct object_id oid;
 212        mmbuffer_t result_buf;
 213        struct object_id threeway[3];
 214        unsigned mode = 0;
 215
 216        memset(threeway, 0, sizeof(threeway));
 217        while (pos < active_nr) {
 218                int stage;
 219                stage = ce_stage(ce);
 220                if (!stage || strcmp(path, ce->name))
 221                        break;
 222                oidcpy(&threeway[stage - 1], &ce->oid);
 223                if (stage == 2)
 224                        mode = create_ce_mode(ce->ce_mode);
 225                pos++;
 226                ce = active_cache[pos];
 227        }
 228        if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 229                return error(_("path '%s' does not have necessary versions"), path);
 230
 231        read_mmblob(&ancestor, &threeway[0]);
 232        read_mmblob(&ours, &threeway[1]);
 233        read_mmblob(&theirs, &threeway[2]);
 234
 235        /*
 236         * NEEDSWORK: re-create conflicts from merges with
 237         * merge.renormalize set, too
 238         */
 239        status = ll_merge(&result_buf, path, &ancestor, "base",
 240                          &ours, "ours", &theirs, "theirs",
 241                          state->istate, NULL);
 242        free(ancestor.ptr);
 243        free(ours.ptr);
 244        free(theirs.ptr);
 245        if (status < 0 || !result_buf.ptr) {
 246                free(result_buf.ptr);
 247                return error(_("path '%s': cannot merge"), path);
 248        }
 249
 250        /*
 251         * NEEDSWORK:
 252         * There is absolutely no reason to write this as a blob object
 253         * and create a phony cache entry.  This hack is primarily to get
 254         * to the write_entry() machinery that massages the contents to
 255         * work-tree format and writes out which only allows it for a
 256         * cache entry.  The code in write_entry() needs to be refactored
 257         * to allow us to feed a <buffer, size, mode> instead of a cache
 258         * entry.  Such a refactoring would help merge_recursive as well
 259         * (it also writes the merge result to the object database even
 260         * when it may contain conflicts).
 261         */
 262        if (write_object_file(result_buf.ptr, result_buf.size, blob_type, &oid))
 263                die(_("Unable to add merge result for '%s'"), path);
 264        free(result_buf.ptr);
 265        ce = make_transient_cache_entry(mode, &oid, path, 2);
 266        if (!ce)
 267                die(_("make_cache_entry failed for path '%s'"), path);
 268        status = checkout_entry(ce, state, NULL, nr_checkouts);
 269        discard_cache_entry(ce);
 270        return status;
 271}
 272
 273static void mark_ce_for_checkout_overlay(struct cache_entry *ce,
 274                                         char *ps_matched,
 275                                         const struct checkout_opts *opts)
 276{
 277        ce->ce_flags &= ~CE_MATCHED;
 278        if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 279                return;
 280        if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 281                /*
 282                 * "git checkout tree-ish -- path", but this entry
 283                 * is in the original index but is not in tree-ish
 284                 * or does not match the pathspec; it will not be
 285                 * checked out to the working tree.  We will not do
 286                 * anything to this entry at all.
 287                 */
 288                return;
 289        /*
 290         * Either this entry came from the tree-ish we are
 291         * checking the paths out of, or we are checking out
 292         * of the index.
 293         *
 294         * If it comes from the tree-ish, we already know it
 295         * matches the pathspec and could just stamp
 296         * CE_MATCHED to it from update_some(). But we still
 297         * need ps_matched and read_tree_recursive (and
 298         * eventually tree_entry_interesting) cannot fill
 299         * ps_matched yet. Once it can, we can avoid calling
 300         * match_pathspec() for _all_ entries when
 301         * opts->source_tree != NULL.
 302         */
 303        if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched))
 304                ce->ce_flags |= CE_MATCHED;
 305}
 306
 307static void mark_ce_for_checkout_no_overlay(struct cache_entry *ce,
 308                                            char *ps_matched,
 309                                            const struct checkout_opts *opts)
 310{
 311        ce->ce_flags &= ~CE_MATCHED;
 312        if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 313                return;
 314        if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched)) {
 315                ce->ce_flags |= CE_MATCHED;
 316                if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 317                        /*
 318                         * In overlay mode, but the path is not in
 319                         * tree-ish, which means we should remove it
 320                         * from the index and the working tree.
 321                         */
 322                        ce->ce_flags |= CE_REMOVE | CE_WT_REMOVE;
 323        }
 324}
 325
 326static int checkout_paths(const struct checkout_opts *opts,
 327                          const char *revision)
 328{
 329        int pos;
 330        struct checkout state = CHECKOUT_INIT;
 331        static char *ps_matched;
 332        struct object_id rev;
 333        struct commit *head;
 334        int errs = 0;
 335        struct lock_file lock_file = LOCK_INIT;
 336        int nr_checkouts = 0, nr_unmerged = 0;
 337
 338        trace2_cmd_mode(opts->patch_mode ? "patch" : "path");
 339
 340        if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 341                die(_("'%s' cannot be used with updating paths"), "--track");
 342
 343        if (opts->new_branch_log)
 344                die(_("'%s' cannot be used with updating paths"), "-l");
 345
 346        if (opts->force && opts->patch_mode)
 347                die(_("'%s' cannot be used with updating paths"), "-f");
 348
 349        if (opts->force_detach)
 350                die(_("'%s' cannot be used with updating paths"), "--detach");
 351
 352        if (opts->merge && opts->patch_mode)
 353                die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 354
 355        if (opts->force && opts->merge)
 356                die(_("'%s' cannot be used with %s"), "-f", "-m");
 357
 358        if (opts->new_branch)
 359                die(_("Cannot update paths and switch to branch '%s' at the same time."),
 360                    opts->new_branch);
 361
 362        if (opts->patch_mode)
 363                return run_add_interactive(revision, "--patch=checkout",
 364                                           &opts->pathspec);
 365
 366        repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);
 367        if (read_cache_preload(&opts->pathspec) < 0)
 368                return error(_("index file corrupt"));
 369
 370        if (opts->source_tree)
 371                read_tree_some(opts->source_tree, &opts->pathspec);
 372
 373        ps_matched = xcalloc(opts->pathspec.nr, 1);
 374
 375        /*
 376         * Make sure all pathspecs participated in locating the paths
 377         * to be checked out.
 378         */
 379        for (pos = 0; pos < active_nr; pos++)
 380                if (opts->overlay_mode)
 381                        mark_ce_for_checkout_overlay(active_cache[pos],
 382                                                     ps_matched,
 383                                                     opts);
 384                else
 385                        mark_ce_for_checkout_no_overlay(active_cache[pos],
 386                                                        ps_matched,
 387                                                        opts);
 388
 389        if (report_path_error(ps_matched, &opts->pathspec, opts->prefix)) {
 390                free(ps_matched);
 391                return 1;
 392        }
 393        free(ps_matched);
 394
 395        /* "checkout -m path" to recreate conflicted state */
 396        if (opts->merge)
 397                unmerge_marked_index(&the_index);
 398
 399        /* Any unmerged paths? */
 400        for (pos = 0; pos < active_nr; pos++) {
 401                const struct cache_entry *ce = active_cache[pos];
 402                if (ce->ce_flags & CE_MATCHED) {
 403                        if (!ce_stage(ce))
 404                                continue;
 405                        if (opts->force) {
 406                                warning(_("path '%s' is unmerged"), ce->name);
 407                        } else if (opts->writeout_stage) {
 408                                errs |= check_stage(opts->writeout_stage, ce, pos, opts->overlay_mode);
 409                        } else if (opts->merge) {
 410                                errs |= check_stages((1<<2) | (1<<3), ce, pos);
 411                        } else {
 412                                errs = 1;
 413                                error(_("path '%s' is unmerged"), ce->name);
 414                        }
 415                        pos = skip_same_name(ce, pos) - 1;
 416                }
 417        }
 418        if (errs)
 419                return 1;
 420
 421        /* Now we are committed to check them out */
 422        state.force = 1;
 423        state.refresh_cache = 1;
 424        state.istate = &the_index;
 425
 426        enable_delayed_checkout(&state);
 427        for (pos = 0; pos < active_nr; pos++) {
 428                struct cache_entry *ce = active_cache[pos];
 429                if (ce->ce_flags & CE_MATCHED) {
 430                        if (!ce_stage(ce)) {
 431                                errs |= checkout_entry(ce, &state,
 432                                                       NULL, &nr_checkouts);
 433                                continue;
 434                        }
 435                        if (opts->writeout_stage)
 436                                errs |= checkout_stage(opts->writeout_stage,
 437                                                       ce, pos,
 438                                                       &state,
 439                                                       &nr_checkouts, opts->overlay_mode);
 440                        else if (opts->merge)
 441                                errs |= checkout_merged(pos, &state,
 442                                                        &nr_unmerged);
 443                        pos = skip_same_name(ce, pos) - 1;
 444                }
 445        }
 446        remove_marked_cache_entries(&the_index, 1);
 447        remove_scheduled_dirs();
 448        errs |= finish_delayed_checkout(&state, &nr_checkouts);
 449
 450        if (opts->count_checkout_paths) {
 451                if (nr_unmerged)
 452                        fprintf_ln(stderr, Q_("Recreated %d merge conflict",
 453                                              "Recreated %d merge conflicts",
 454                                              nr_unmerged),
 455                                   nr_unmerged);
 456                if (opts->source_tree)
 457                        fprintf_ln(stderr, Q_("Updated %d path from %s",
 458                                              "Updated %d paths from %s",
 459                                              nr_checkouts),
 460                                   nr_checkouts,
 461                                   find_unique_abbrev(&opts->source_tree->object.oid,
 462                                                      DEFAULT_ABBREV));
 463                else if (!nr_unmerged || nr_checkouts)
 464                        fprintf_ln(stderr, Q_("Updated %d path from the index",
 465                                              "Updated %d paths from the index",
 466                                              nr_checkouts),
 467                                   nr_checkouts);
 468        }
 469
 470        if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 471                die(_("unable to write new index file"));
 472
 473        read_ref_full("HEAD", 0, &rev, NULL);
 474        head = lookup_commit_reference_gently(the_repository, &rev, 1);
 475
 476        errs |= post_checkout_hook(head, head, 0);
 477        return errs;
 478}
 479
 480static void show_local_changes(struct object *head,
 481                               const struct diff_options *opts)
 482{
 483        struct rev_info rev;
 484        /* I think we want full paths, even if we're in a subdirectory. */
 485        repo_init_revisions(the_repository, &rev, NULL);
 486        rev.diffopt.flags = opts->flags;
 487        rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 488        diff_setup_done(&rev.diffopt);
 489        add_pending_object(&rev, head, NULL);
 490        run_diff_index(&rev, 0);
 491}
 492
 493static void describe_detached_head(const char *msg, struct commit *commit)
 494{
 495        struct strbuf sb = STRBUF_INIT;
 496
 497        if (!parse_commit(commit))
 498                pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 499        if (print_sha1_ellipsis()) {
 500                fprintf(stderr, "%s %s... %s\n", msg,
 501                        find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 502        } else {
 503                fprintf(stderr, "%s %s %s\n", msg,
 504                        find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 505        }
 506        strbuf_release(&sb);
 507}
 508
 509static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 510                      int worktree, int *writeout_error)
 511{
 512        struct unpack_trees_options opts;
 513        struct tree_desc tree_desc;
 514
 515        memset(&opts, 0, sizeof(opts));
 516        opts.head_idx = -1;
 517        opts.update = worktree;
 518        opts.skip_unmerged = !worktree;
 519        opts.reset = 1;
 520        opts.merge = 1;
 521        opts.fn = oneway_merge;
 522        opts.verbose_update = o->show_progress;
 523        opts.src_index = &the_index;
 524        opts.dst_index = &the_index;
 525        parse_tree(tree);
 526        init_tree_desc(&tree_desc, tree->buffer, tree->size);
 527        switch (unpack_trees(1, &tree_desc, &opts)) {
 528        case -2:
 529                *writeout_error = 1;
 530                /*
 531                 * We return 0 nevertheless, as the index is all right
 532                 * and more importantly we have made best efforts to
 533                 * update paths in the work tree, and we cannot revert
 534                 * them.
 535                 */
 536                /* fallthrough */
 537        case 0:
 538                return 0;
 539        default:
 540                return 128;
 541        }
 542}
 543
 544struct branch_info {
 545        const char *name; /* The short name used */
 546        const char *path; /* The full name of a real branch */
 547        struct commit *commit; /* The named commit */
 548        /*
 549         * if not null the branch is detached because it's already
 550         * checked out in this checkout
 551         */
 552        char *checkout;
 553};
 554
 555static void setup_branch_path(struct branch_info *branch)
 556{
 557        struct strbuf buf = STRBUF_INIT;
 558
 559        strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 560        if (strcmp(buf.buf, branch->name))
 561                branch->name = xstrdup(buf.buf);
 562        strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 563        branch->path = strbuf_detach(&buf, NULL);
 564}
 565
 566/*
 567 * Skip merging the trees, updating the index and working directory if and
 568 * only if we are creating a new branch via "git checkout -b <new_branch>."
 569 */
 570static int skip_merge_working_tree(const struct checkout_opts *opts,
 571        const struct branch_info *old_branch_info,
 572        const struct branch_info *new_branch_info)
 573{
 574        /*
 575         * Do the merge if sparse checkout is on and the user has not opted in
 576         * to the optimized behavior
 577         */
 578        if (core_apply_sparse_checkout && !checkout_optimize_new_branch)
 579                return 0;
 580
 581        /*
 582         * We must do the merge if we are actually moving to a new commit.
 583         */
 584        if (!old_branch_info->commit || !new_branch_info->commit ||
 585                !oideq(&old_branch_info->commit->object.oid,
 586                       &new_branch_info->commit->object.oid))
 587                return 0;
 588
 589        /*
 590         * opts->patch_mode cannot be used with switching branches so is
 591         * not tested here
 592         */
 593
 594        /*
 595         * opts->quiet only impacts output so doesn't require a merge
 596         */
 597
 598        /*
 599         * Honor the explicit request for a three-way merge or to throw away
 600         * local changes
 601         */
 602        if (opts->merge || opts->force)
 603                return 0;
 604
 605        /*
 606         * --detach is documented as "updating the index and the files in the
 607         * working tree" but this optimization skips those steps so fall through
 608         * to the regular code path.
 609         */
 610        if (opts->force_detach)
 611                return 0;
 612
 613        /*
 614         * opts->writeout_stage cannot be used with switching branches so is
 615         * not tested here
 616         */
 617
 618        /*
 619         * Honor the explicit ignore requests
 620         */
 621        if (!opts->overwrite_ignore || opts->ignore_skipworktree ||
 622                opts->ignore_other_worktrees)
 623                return 0;
 624
 625        /*
 626         * opts->show_progress only impacts output so doesn't require a merge
 627         */
 628
 629        /*
 630         * opts->overlay_mode cannot be used with switching branches so is
 631         * not tested here
 632         */
 633
 634        /*
 635         * If we aren't creating a new branch any changes or updates will
 636         * happen in the existing branch.  Since that could only be updating
 637         * the index and working directory, we don't want to skip those steps
 638         * or we've defeated any purpose in running the command.
 639         */
 640        if (!opts->new_branch)
 641                return 0;
 642
 643        /*
 644         * new_branch_force is defined to "create/reset and checkout a branch"
 645         * so needs to go through the merge to do the reset
 646         */
 647        if (opts->new_branch_force)
 648                return 0;
 649
 650        /*
 651         * A new orphaned branch requrires the index and the working tree to be
 652         * adjusted to <start_point>
 653         */
 654        if (opts->new_orphan_branch)
 655                return 0;
 656
 657        /*
 658         * Remaining variables are not checkout options but used to track state
 659         */
 660
 661         /*
 662          * Do the merge if this is the initial checkout. We cannot use
 663          * is_cache_unborn() here because the index hasn't been loaded yet
 664          * so cache_nr and timestamp.sec are always zero.
 665          */
 666        if (!file_exists(get_index_file()))
 667                return 0;
 668
 669        return 1;
 670}
 671
 672static int merge_working_tree(const struct checkout_opts *opts,
 673                              struct branch_info *old_branch_info,
 674                              struct branch_info *new_branch_info,
 675                              int *writeout_error)
 676{
 677        int ret;
 678        struct lock_file lock_file = LOCK_INIT;
 679
 680        hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 681        if (read_cache_preload(NULL) < 0)
 682                return error(_("index file corrupt"));
 683
 684        resolve_undo_clear();
 685        if (opts->discard_changes) {
 686                ret = reset_tree(get_commit_tree(new_branch_info->commit),
 687                                 opts, 1, writeout_error);
 688                if (ret)
 689                        return ret;
 690        } else {
 691                struct tree_desc trees[2];
 692                struct tree *tree;
 693                struct unpack_trees_options topts;
 694
 695                memset(&topts, 0, sizeof(topts));
 696                topts.head_idx = -1;
 697                topts.src_index = &the_index;
 698                topts.dst_index = &the_index;
 699
 700                setup_unpack_trees_porcelain(&topts, "checkout");
 701
 702                refresh_cache(REFRESH_QUIET);
 703
 704                if (unmerged_cache()) {
 705                        error(_("you need to resolve your current index first"));
 706                        return 1;
 707                }
 708
 709                /* 2-way merge to the new branch */
 710                topts.initial_checkout = is_cache_unborn();
 711                topts.update = 1;
 712                topts.merge = 1;
 713                topts.gently = opts->merge && old_branch_info->commit;
 714                topts.verbose_update = opts->show_progress;
 715                topts.fn = twoway_merge;
 716                if (opts->overwrite_ignore) {
 717                        topts.dir = xcalloc(1, sizeof(*topts.dir));
 718                        topts.dir->flags |= DIR_SHOW_IGNORED;
 719                        setup_standard_excludes(topts.dir);
 720                }
 721                tree = parse_tree_indirect(old_branch_info->commit ?
 722                                           &old_branch_info->commit->object.oid :
 723                                           the_hash_algo->empty_tree);
 724                init_tree_desc(&trees[0], tree->buffer, tree->size);
 725                tree = parse_tree_indirect(&new_branch_info->commit->object.oid);
 726                init_tree_desc(&trees[1], tree->buffer, tree->size);
 727
 728                ret = unpack_trees(2, trees, &topts);
 729                clear_unpack_trees_porcelain(&topts);
 730                if (ret == -1) {
 731                        /*
 732                         * Unpack couldn't do a trivial merge; either
 733                         * give up or do a real merge, depending on
 734                         * whether the merge flag was used.
 735                         */
 736                        struct tree *result;
 737                        struct tree *work;
 738                        struct merge_options o;
 739                        if (!opts->merge)
 740                                return 1;
 741
 742                        /*
 743                         * Without old_branch_info->commit, the below is the same as
 744                         * the two-tree unpack we already tried and failed.
 745                         */
 746                        if (!old_branch_info->commit)
 747                                return 1;
 748
 749                        /* Do more real merge */
 750
 751                        /*
 752                         * We update the index fully, then write the
 753                         * tree from the index, then merge the new
 754                         * branch with the current tree, with the old
 755                         * branch as the base. Then we reset the index
 756                         * (but not the working tree) to the new
 757                         * branch, leaving the working tree as the
 758                         * merged version, but skipping unmerged
 759                         * entries in the index.
 760                         */
 761
 762                        add_files_to_cache(NULL, NULL, 0);
 763                        /*
 764                         * NEEDSWORK: carrying over local changes
 765                         * when branches have different end-of-line
 766                         * normalization (or clean+smudge rules) is
 767                         * a pain; plumb in an option to set
 768                         * o.renormalize?
 769                         */
 770                        init_merge_options(&o, the_repository);
 771                        o.verbosity = 0;
 772                        work = write_tree_from_memory(&o);
 773
 774                        ret = reset_tree(get_commit_tree(new_branch_info->commit),
 775                                         opts, 1,
 776                                         writeout_error);
 777                        if (ret)
 778                                return ret;
 779                        o.ancestor = old_branch_info->name;
 780                        o.branch1 = new_branch_info->name;
 781                        o.branch2 = "local";
 782                        ret = merge_trees(&o,
 783                                          get_commit_tree(new_branch_info->commit),
 784                                          work,
 785                                          get_commit_tree(old_branch_info->commit),
 786                                          &result);
 787                        if (ret < 0)
 788                                exit(128);
 789                        ret = reset_tree(get_commit_tree(new_branch_info->commit),
 790                                         opts, 0,
 791                                         writeout_error);
 792                        strbuf_release(&o.obuf);
 793                        if (ret)
 794                                return ret;
 795                }
 796        }
 797
 798        if (!active_cache_tree)
 799                active_cache_tree = cache_tree();
 800
 801        if (!cache_tree_fully_valid(active_cache_tree))
 802                cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 803
 804        if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 805                die(_("unable to write new index file"));
 806
 807        if (!opts->discard_changes && !opts->quiet)
 808                show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
 809
 810        return 0;
 811}
 812
 813static void report_tracking(struct branch_info *new_branch_info)
 814{
 815        struct strbuf sb = STRBUF_INIT;
 816        struct branch *branch = branch_get(new_branch_info->name);
 817
 818        if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL))
 819                return;
 820        fputs(sb.buf, stdout);
 821        strbuf_release(&sb);
 822}
 823
 824static void update_refs_for_switch(const struct checkout_opts *opts,
 825                                   struct branch_info *old_branch_info,
 826                                   struct branch_info *new_branch_info)
 827{
 828        struct strbuf msg = STRBUF_INIT;
 829        const char *old_desc, *reflog_msg;
 830        if (opts->new_branch) {
 831                if (opts->new_orphan_branch) {
 832                        char *refname;
 833
 834                        refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 835                        if (opts->new_branch_log &&
 836                            !should_autocreate_reflog(refname)) {
 837                                int ret;
 838                                struct strbuf err = STRBUF_INIT;
 839
 840                                ret = safe_create_reflog(refname, 1, &err);
 841                                if (ret) {
 842                                        fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 843                                                opts->new_orphan_branch, err.buf);
 844                                        strbuf_release(&err);
 845                                        free(refname);
 846                                        return;
 847                                }
 848                                strbuf_release(&err);
 849                        }
 850                        free(refname);
 851                }
 852                else
 853                        create_branch(the_repository,
 854                                      opts->new_branch, new_branch_info->name,
 855                                      opts->new_branch_force ? 1 : 0,
 856                                      opts->new_branch_force ? 1 : 0,
 857                                      opts->new_branch_log,
 858                                      opts->quiet,
 859                                      opts->track);
 860                new_branch_info->name = opts->new_branch;
 861                setup_branch_path(new_branch_info);
 862        }
 863
 864        old_desc = old_branch_info->name;
 865        if (!old_desc && old_branch_info->commit)
 866                old_desc = oid_to_hex(&old_branch_info->commit->object.oid);
 867
 868        reflog_msg = getenv("GIT_REFLOG_ACTION");
 869        if (!reflog_msg)
 870                strbuf_addf(&msg, "checkout: moving from %s to %s",
 871                        old_desc ? old_desc : "(invalid)", new_branch_info->name);
 872        else
 873                strbuf_insert(&msg, 0, reflog_msg, strlen(reflog_msg));
 874
 875        if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
 876                /* Nothing to do. */
 877        } else if (opts->force_detach || !new_branch_info->path) {      /* No longer on any branch. */
 878                update_ref(msg.buf, "HEAD", &new_branch_info->commit->object.oid, NULL,
 879                           REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
 880                if (!opts->quiet) {
 881                        if (old_branch_info->path &&
 882                            advice_detached_head && !opts->force_detach)
 883                                detach_advice(new_branch_info->name);
 884                        describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
 885                }
 886        } else if (new_branch_info->path) {     /* Switch branches. */
 887                if (create_symref("HEAD", new_branch_info->path, msg.buf) < 0)
 888                        die(_("unable to update HEAD"));
 889                if (!opts->quiet) {
 890                        if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
 891                                if (opts->new_branch_force)
 892                                        fprintf(stderr, _("Reset branch '%s'\n"),
 893                                                new_branch_info->name);
 894                                else
 895                                        fprintf(stderr, _("Already on '%s'\n"),
 896                                                new_branch_info->name);
 897                        } else if (opts->new_branch) {
 898                                if (opts->branch_exists)
 899                                        fprintf(stderr, _("Switched to and reset branch '%s'\n"), new_branch_info->name);
 900                                else
 901                                        fprintf(stderr, _("Switched to a new branch '%s'\n"), new_branch_info->name);
 902                        } else {
 903                                fprintf(stderr, _("Switched to branch '%s'\n"),
 904                                        new_branch_info->name);
 905                        }
 906                }
 907                if (old_branch_info->path && old_branch_info->name) {
 908                        if (!ref_exists(old_branch_info->path) && reflog_exists(old_branch_info->path))
 909                                delete_reflog(old_branch_info->path);
 910                }
 911        }
 912        remove_branch_state(the_repository, !opts->quiet);
 913        strbuf_release(&msg);
 914        if (!opts->quiet &&
 915            (new_branch_info->path || (!opts->force_detach && !strcmp(new_branch_info->name, "HEAD"))))
 916                report_tracking(new_branch_info);
 917}
 918
 919static int add_pending_uninteresting_ref(const char *refname,
 920                                         const struct object_id *oid,
 921                                         int flags, void *cb_data)
 922{
 923        add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 924        return 0;
 925}
 926
 927static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 928{
 929        strbuf_addstr(sb, "  ");
 930        strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
 931        strbuf_addch(sb, ' ');
 932        if (!parse_commit(commit))
 933                pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 934        strbuf_addch(sb, '\n');
 935}
 936
 937#define ORPHAN_CUTOFF 4
 938static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 939{
 940        struct commit *c, *last = NULL;
 941        struct strbuf sb = STRBUF_INIT;
 942        int lost = 0;
 943        while ((c = get_revision(revs)) != NULL) {
 944                if (lost < ORPHAN_CUTOFF)
 945                        describe_one_orphan(&sb, c);
 946                last = c;
 947                lost++;
 948        }
 949        if (ORPHAN_CUTOFF < lost) {
 950                int more = lost - ORPHAN_CUTOFF;
 951                if (more == 1)
 952                        describe_one_orphan(&sb, last);
 953                else
 954                        strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 955        }
 956
 957        fprintf(stderr,
 958                Q_(
 959                /* The singular version */
 960                "Warning: you are leaving %d commit behind, "
 961                "not connected to\n"
 962                "any of your branches:\n\n"
 963                "%s\n",
 964                /* The plural version */
 965                "Warning: you are leaving %d commits behind, "
 966                "not connected to\n"
 967                "any of your branches:\n\n"
 968                "%s\n",
 969                /* Give ngettext() the count */
 970                lost),
 971                lost,
 972                sb.buf);
 973        strbuf_release(&sb);
 974
 975        if (advice_detached_head)
 976                fprintf(stderr,
 977                        Q_(
 978                        /* The singular version */
 979                        "If you want to keep it by creating a new branch, "
 980                        "this may be a good time\nto do so with:\n\n"
 981                        " git branch <new-branch-name> %s\n\n",
 982                        /* The plural version */
 983                        "If you want to keep them by creating a new branch, "
 984                        "this may be a good time\nto do so with:\n\n"
 985                        " git branch <new-branch-name> %s\n\n",
 986                        /* Give ngettext() the count */
 987                        lost),
 988                        find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
 989}
 990
 991/*
 992 * We are about to leave commit that was at the tip of a detached
 993 * HEAD.  If it is not reachable from any ref, this is the last chance
 994 * for the user to do so without resorting to reflog.
 995 */
 996static void orphaned_commit_warning(struct commit *old_commit, struct commit *new_commit)
 997{
 998        struct rev_info revs;
 999        struct object *object = &old_commit->object;
1000
1001        repo_init_revisions(the_repository, &revs, NULL);
1002        setup_revisions(0, NULL, &revs, NULL);
1003
1004        object->flags &= ~UNINTERESTING;
1005        add_pending_object(&revs, object, oid_to_hex(&object->oid));
1006
1007        for_each_ref(add_pending_uninteresting_ref, &revs);
1008        add_pending_oid(&revs, "HEAD", &new_commit->object.oid, UNINTERESTING);
1009
1010        if (prepare_revision_walk(&revs))
1011                die(_("internal error in revision walk"));
1012        if (!(old_commit->object.flags & UNINTERESTING))
1013                suggest_reattach(old_commit, &revs);
1014        else
1015                describe_detached_head(_("Previous HEAD position was"), old_commit);
1016
1017        /* Clean up objects used, as they will be reused. */
1018        clear_commit_marks_all(ALL_REV_FLAGS);
1019}
1020
1021static int switch_branches(const struct checkout_opts *opts,
1022                           struct branch_info *new_branch_info)
1023{
1024        int ret = 0;
1025        struct branch_info old_branch_info;
1026        void *path_to_free;
1027        struct object_id rev;
1028        int flag, writeout_error = 0;
1029
1030        trace2_cmd_mode("branch");
1031
1032        memset(&old_branch_info, 0, sizeof(old_branch_info));
1033        old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
1034        if (old_branch_info.path)
1035                old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
1036        if (!(flag & REF_ISSYMREF))
1037                old_branch_info.path = NULL;
1038
1039        if (old_branch_info.path)
1040                skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
1041
1042        if (!new_branch_info->name) {
1043                new_branch_info->name = "HEAD";
1044                new_branch_info->commit = old_branch_info.commit;
1045                if (!new_branch_info->commit)
1046                        die(_("You are on a branch yet to be born"));
1047                parse_commit_or_die(new_branch_info->commit);
1048        }
1049
1050        /* optimize the "checkout -b <new_branch> path */
1051        if (skip_merge_working_tree(opts, &old_branch_info, new_branch_info)) {
1052                if (!checkout_optimize_new_branch && !opts->quiet) {
1053                        if (read_cache_preload(NULL) < 0)
1054                                return error(_("index file corrupt"));
1055                        show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
1056                }
1057        } else {
1058                ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error);
1059                if (ret) {
1060                        free(path_to_free);
1061                        return ret;
1062                }
1063        }
1064
1065        if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit)
1066                orphaned_commit_warning(old_branch_info.commit, new_branch_info->commit);
1067
1068        update_refs_for_switch(opts, &old_branch_info, new_branch_info);
1069
1070        ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
1071        free(path_to_free);
1072        return ret || writeout_error;
1073}
1074
1075static int git_checkout_config(const char *var, const char *value, void *cb)
1076{
1077        if (!strcmp(var, "checkout.optimizenewbranch")) {
1078                checkout_optimize_new_branch = git_config_bool(var, value);
1079                return 0;
1080        }
1081
1082        if (!strcmp(var, "diff.ignoresubmodules")) {
1083                struct checkout_opts *opts = cb;
1084                handle_ignore_submodules_arg(&opts->diff_options, value);
1085                return 0;
1086        }
1087
1088        if (starts_with(var, "submodule."))
1089                return git_default_submodule_config(var, value, NULL);
1090
1091        return git_xmerge_config(var, value, NULL);
1092}
1093
1094static void setup_new_branch_info_and_source_tree(
1095        struct branch_info *new_branch_info,
1096        struct checkout_opts *opts,
1097        struct object_id *rev,
1098        const char *arg)
1099{
1100        struct tree **source_tree = &opts->source_tree;
1101        struct object_id branch_rev;
1102
1103        new_branch_info->name = arg;
1104        setup_branch_path(new_branch_info);
1105
1106        if (!check_refname_format(new_branch_info->path, 0) &&
1107            !read_ref(new_branch_info->path, &branch_rev))
1108                oidcpy(rev, &branch_rev);
1109        else
1110                new_branch_info->path = NULL; /* not an existing branch */
1111
1112        new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
1113        if (!new_branch_info->commit) {
1114                /* not a commit */
1115                *source_tree = parse_tree_indirect(rev);
1116        } else {
1117                parse_commit_or_die(new_branch_info->commit);
1118                *source_tree = get_commit_tree(new_branch_info->commit);
1119        }
1120}
1121
1122static int parse_branchname_arg(int argc, const char **argv,
1123                                int dwim_new_local_branch_ok,
1124                                struct branch_info *new_branch_info,
1125                                struct checkout_opts *opts,
1126                                struct object_id *rev,
1127                                int *dwim_remotes_matched)
1128{
1129        const char **new_branch = &opts->new_branch;
1130        int argcount = 0;
1131        const char *arg;
1132        int dash_dash_pos;
1133        int has_dash_dash = 0;
1134        int i;
1135
1136        /*
1137         * case 1: git checkout <ref> -- [<paths>]
1138         *
1139         *   <ref> must be a valid tree, everything after the '--' must be
1140         *   a path.
1141         *
1142         * case 2: git checkout -- [<paths>]
1143         *
1144         *   everything after the '--' must be paths.
1145         *
1146         * case 3: git checkout <something> [--]
1147         *
1148         *   (a) If <something> is a commit, that is to
1149         *       switch to the branch or detach HEAD at it.  As a special case,
1150         *       if <something> is A...B (missing A or B means HEAD but you can
1151         *       omit at most one side), and if there is a unique merge base
1152         *       between A and B, A...B names that merge base.
1153         *
1154         *   (b) If <something> is _not_ a commit, either "--" is present
1155         *       or <something> is not a path, no -t or -b was given, and
1156         *       and there is a tracking branch whose name is <something>
1157         *       in one and only one remote (or if the branch exists on the
1158         *       remote named in checkout.defaultRemote), then this is a
1159         *       short-hand to fork local <something> from that
1160         *       remote-tracking branch.
1161         *
1162         *   (c) Otherwise, if "--" is present, treat it like case (1).
1163         *
1164         *   (d) Otherwise :
1165         *       - if it's a reference, treat it like case (1)
1166         *       - else if it's a path, treat it like case (2)
1167         *       - else: fail.
1168         *
1169         * case 4: git checkout <something> <paths>
1170         *
1171         *   The first argument must not be ambiguous.
1172         *   - If it's *only* a reference, treat it like case (1).
1173         *   - If it's only a path, treat it like case (2).
1174         *   - else: fail.
1175         *
1176         */
1177        if (!argc)
1178                return 0;
1179
1180        if (!opts->accept_pathspec) {
1181                if (argc > 1)
1182                        die(_("only one reference expected"));
1183                has_dash_dash = 1; /* helps disambiguate */
1184        }
1185
1186        arg = argv[0];
1187        dash_dash_pos = -1;
1188        for (i = 0; i < argc; i++) {
1189                if (opts->accept_pathspec && !strcmp(argv[i], "--")) {
1190                        dash_dash_pos = i;
1191                        break;
1192                }
1193        }
1194        if (dash_dash_pos == 0)
1195                return 1; /* case (2) */
1196        else if (dash_dash_pos == 1)
1197                has_dash_dash = 1; /* case (3) or (1) */
1198        else if (dash_dash_pos >= 2)
1199                die(_("only one reference expected, %d given."), dash_dash_pos);
1200        opts->count_checkout_paths = !opts->quiet && !has_dash_dash;
1201
1202        if (!strcmp(arg, "-"))
1203                arg = "@{-1}";
1204
1205        if (get_oid_mb(arg, rev)) {
1206                /*
1207                 * Either case (3) or (4), with <something> not being
1208                 * a commit, or an attempt to use case (1) with an
1209                 * invalid ref.
1210                 *
1211                 * It's likely an error, but we need to find out if
1212                 * we should auto-create the branch, case (3).(b).
1213                 */
1214                int recover_with_dwim = dwim_new_local_branch_ok;
1215
1216                int could_be_checkout_paths = !has_dash_dash &&
1217                        check_filename(opts->prefix, arg);
1218
1219                if (!has_dash_dash && !no_wildcard(arg))
1220                        recover_with_dwim = 0;
1221
1222                /*
1223                 * Accept "git checkout foo", "git checkout foo --"
1224                 * and "git switch foo" as candidates for dwim.
1225                 */
1226                if (!(argc == 1 && !has_dash_dash) &&
1227                    !(argc == 2 && has_dash_dash) &&
1228                    opts->accept_pathspec)
1229                        recover_with_dwim = 0;
1230
1231                if (recover_with_dwim) {
1232                        const char *remote = unique_tracking_name(arg, rev,
1233                                                                  dwim_remotes_matched);
1234                        if (remote) {
1235                                if (could_be_checkout_paths)
1236                                        die(_("'%s' could be both a local file and a tracking branch.\n"
1237                                              "Please use -- (and optionally --no-guess) to disambiguate"),
1238                                            arg);
1239                                *new_branch = arg;
1240                                arg = remote;
1241                                /* DWIMmed to create local branch, case (3).(b) */
1242                        } else {
1243                                recover_with_dwim = 0;
1244                        }
1245                }
1246
1247                if (!recover_with_dwim) {
1248                        if (has_dash_dash)
1249                                die(_("invalid reference: %s"), arg);
1250                        return argcount;
1251                }
1252        }
1253
1254        /* we can't end up being in (2) anymore, eat the argument */
1255        argcount++;
1256        argv++;
1257        argc--;
1258
1259        setup_new_branch_info_and_source_tree(new_branch_info, opts, rev, arg);
1260
1261        if (!opts->source_tree)                   /* case (1): want a tree */
1262                die(_("reference is not a tree: %s"), arg);
1263
1264        if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1265                /*
1266                 * Do not complain the most common case
1267                 *      git checkout branch
1268                 * even if there happen to be a file called 'branch';
1269                 * it would be extremely annoying.
1270                 */
1271                if (argc)
1272                        verify_non_filename(opts->prefix, arg);
1273        } else if (opts->accept_pathspec) {
1274                argcount++;
1275                argv++;
1276                argc--;
1277        }
1278
1279        return argcount;
1280}
1281
1282static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1283{
1284        int status;
1285        struct strbuf branch_ref = STRBUF_INIT;
1286
1287        trace2_cmd_mode("unborn");
1288
1289        if (!opts->new_branch)
1290                die(_("You are on a branch yet to be born"));
1291        strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1292        status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1293        strbuf_release(&branch_ref);
1294        if (!opts->quiet)
1295                fprintf(stderr, _("Switched to a new branch '%s'\n"),
1296                        opts->new_branch);
1297        return status;
1298}
1299
1300static int checkout_branch(struct checkout_opts *opts,
1301                           struct branch_info *new_branch_info)
1302{
1303        if (opts->pathspec.nr)
1304                die(_("paths cannot be used with switching branches"));
1305
1306        if (opts->patch_mode)
1307                die(_("'%s' cannot be used with switching branches"),
1308                    "--patch");
1309
1310        if (!opts->overlay_mode)
1311                die(_("'%s' cannot be used with switching branches"),
1312                    "--no-overlay");
1313
1314        if (opts->writeout_stage)
1315                die(_("'%s' cannot be used with switching branches"),
1316                    "--ours/--theirs");
1317
1318        if (opts->force && opts->merge)
1319                die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1320
1321        if (opts->discard_changes && opts->merge)
1322                die(_("'%s' cannot be used with '%s'"), "--discard-changes", "--merge");
1323
1324        if (opts->force_detach && opts->new_branch)
1325                die(_("'%s' cannot be used with '%s'"),
1326                    "--detach", "-b/-B/--orphan");
1327
1328        if (opts->new_orphan_branch) {
1329                if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1330                        die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1331        } else if (opts->force_detach) {
1332                if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1333                        die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1334        } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1335                opts->track = git_branch_track;
1336
1337        if (new_branch_info->name && !new_branch_info->commit)
1338                die(_("Cannot switch branch to a non-commit '%s'"),
1339                    new_branch_info->name);
1340
1341        if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
1342            !opts->ignore_other_worktrees) {
1343                int flag;
1344                char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
1345                if (head_ref &&
1346                    (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path)))
1347                        die_if_checked_out(new_branch_info->path, 1);
1348                free(head_ref);
1349        }
1350
1351        if (!new_branch_info->commit && opts->new_branch) {
1352                struct object_id rev;
1353                int flag;
1354
1355                if (!read_ref_full("HEAD", 0, &rev, &flag) &&
1356                    (flag & REF_ISSYMREF) && is_null_oid(&rev))
1357                        return switch_unborn_to_new_branch(opts);
1358        }
1359        return switch_branches(opts, new_branch_info);
1360}
1361
1362static struct option *add_common_options(struct checkout_opts *opts,
1363                                         struct option *prevopts)
1364{
1365        struct option options[] = {
1366                OPT__QUIET(&opts->quiet, N_("suppress progress reporting")),
1367                { OPTION_CALLBACK, 0, "recurse-submodules", NULL,
1368                            "checkout", "control recursive updating of submodules",
1369                            PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
1370                OPT_BOOL(0, "progress", &opts->show_progress, N_("force progress reporting")),
1371                OPT__FORCE(&opts->force, N_("force checkout (throw away local modifications)"),
1372                           PARSE_OPT_NOCOMPLETE),
1373                OPT_BOOL('m', "merge", &opts->merge, N_("perform a 3-way merge with the new branch")),
1374                OPT_STRING(0, "conflict", &opts->conflict_style, N_("style"),
1375                           N_("conflict style (merge or diff3)")),
1376                OPT_END()
1377        };
1378        struct option *newopts = parse_options_concat(prevopts, options);
1379        free(prevopts);
1380        return newopts;
1381}
1382
1383static struct option *add_common_switch_branch_options(
1384        struct checkout_opts *opts, struct option *prevopts)
1385{
1386        struct option options[] = {
1387                OPT_BOOL(0, "detach", &opts->force_detach, N_("detach HEAD at named commit")),
1388                OPT_SET_INT('t', "track",  &opts->track, N_("set upstream info for new branch"),
1389                        BRANCH_TRACK_EXPLICIT),
1390                OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1391                OPT_BOOL_F(0, "overwrite-ignore", &opts->overwrite_ignore,
1392                           N_("update ignored files (default)"),
1393                           PARSE_OPT_NOCOMPLETE),
1394                OPT_BOOL(0, "no-guess", &opts->no_dwim_new_local_branch,
1395                         N_("second guess 'git checkout <no-such-branch>'")),
1396                OPT_BOOL(0, "ignore-other-worktrees", &opts->ignore_other_worktrees,
1397                         N_("do not check if another worktree is holding the given ref")),
1398                OPT_END()
1399        };
1400        struct option *newopts = parse_options_concat(prevopts, options);
1401        free(prevopts);
1402        return newopts;
1403}
1404
1405static struct option *add_checkout_path_options(struct checkout_opts *opts,
1406                                                struct option *prevopts)
1407{
1408        struct option options[] = {
1409                OPT_SET_INT_F('2', "ours", &opts->writeout_stage,
1410                              N_("checkout our version for unmerged files"),
1411                              2, PARSE_OPT_NONEG),
1412                OPT_SET_INT_F('3', "theirs", &opts->writeout_stage,
1413                              N_("checkout their version for unmerged files"),
1414                              3, PARSE_OPT_NONEG),
1415                OPT_BOOL('p', "patch", &opts->patch_mode, N_("select hunks interactively")),
1416                OPT_BOOL(0, "ignore-skip-worktree-bits", &opts->ignore_skipworktree,
1417                         N_("do not limit pathspecs to sparse entries only")),
1418                OPT_BOOL(0, "overlay", &opts->overlay_mode, N_("use overlay mode (default)")),
1419                OPT_END()
1420        };
1421        struct option *newopts = parse_options_concat(prevopts, options);
1422        free(prevopts);
1423        return newopts;
1424}
1425
1426static int checkout_main(int argc, const char **argv, const char *prefix,
1427                         struct checkout_opts *opts, struct option *options,
1428                         const char * const usagestr[])
1429{
1430        struct branch_info new_branch_info;
1431        int dwim_remotes_matched = 0;
1432        int dwim_new_local_branch;
1433
1434        memset(&new_branch_info, 0, sizeof(new_branch_info));
1435        opts->overwrite_ignore = 1;
1436        opts->prefix = prefix;
1437        opts->show_progress = -1;
1438        opts->overlay_mode = -1;
1439
1440        git_config(git_checkout_config, opts);
1441
1442        opts->track = BRANCH_TRACK_UNSPECIFIED;
1443
1444        argc = parse_options(argc, argv, prefix, options, usagestr,
1445                             PARSE_OPT_KEEP_DASHDASH);
1446
1447        dwim_new_local_branch = !opts->no_dwim_new_local_branch;
1448        if (opts->show_progress < 0) {
1449                if (opts->quiet)
1450                        opts->show_progress = 0;
1451                else
1452                        opts->show_progress = isatty(2);
1453        }
1454
1455        if (opts->conflict_style) {
1456                opts->merge = 1; /* implied */
1457                git_xmerge_config("merge.conflictstyle", opts->conflict_style, NULL);
1458        }
1459        if (opts->force)
1460                opts->discard_changes = 1;
1461
1462        if ((!!opts->new_branch + !!opts->new_branch_force + !!opts->new_orphan_branch) > 1)
1463                die(_("-b, -B and --orphan are mutually exclusive"));
1464
1465        if (opts->overlay_mode == 1 && opts->patch_mode)
1466                die(_("-p and --overlay are mutually exclusive"));
1467
1468        /*
1469         * From here on, new_branch will contain the branch to be checked out,
1470         * and new_branch_force and new_orphan_branch will tell us which one of
1471         * -b/-B/--orphan is being used.
1472         */
1473        if (opts->new_branch_force)
1474                opts->new_branch = opts->new_branch_force;
1475
1476        if (opts->new_orphan_branch)
1477                opts->new_branch = opts->new_orphan_branch;
1478
1479        /* --track without -b/-B/--orphan should DWIM */
1480        if (opts->track != BRANCH_TRACK_UNSPECIFIED && !opts->new_branch) {
1481                const char *argv0 = argv[0];
1482                if (!argc || !strcmp(argv0, "--"))
1483                        die(_("--track needs a branch name"));
1484                skip_prefix(argv0, "refs/", &argv0);
1485                skip_prefix(argv0, "remotes/", &argv0);
1486                argv0 = strchr(argv0, '/');
1487                if (!argv0 || !argv0[1])
1488                        die(_("missing branch name; try -b"));
1489                opts->new_branch = argv0 + 1;
1490        }
1491
1492        /*
1493         * Extract branch name from command line arguments, so
1494         * all that is left is pathspecs.
1495         *
1496         * Handle
1497         *
1498         *  1) git checkout <tree> -- [<paths>]
1499         *  2) git checkout -- [<paths>]
1500         *  3) git checkout <something> [<paths>]
1501         *
1502         * including "last branch" syntax and DWIM-ery for names of
1503         * remote branches, erroring out for invalid or ambiguous cases.
1504         */
1505        if (argc) {
1506                struct object_id rev;
1507                int dwim_ok =
1508                        !opts->patch_mode &&
1509                        dwim_new_local_branch &&
1510                        opts->track == BRANCH_TRACK_UNSPECIFIED &&
1511                        !opts->new_branch;
1512                int n = parse_branchname_arg(argc, argv, dwim_ok,
1513                                             &new_branch_info, opts, &rev,
1514                                             &dwim_remotes_matched);
1515                argv += n;
1516                argc -= n;
1517        }
1518
1519        if (argc) {
1520                parse_pathspec(&opts->pathspec, 0,
1521                               opts->patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1522                               prefix, argv);
1523
1524                if (!opts->pathspec.nr)
1525                        die(_("invalid path specification"));
1526
1527                /*
1528                 * Try to give more helpful suggestion.
1529                 * new_branch && argc > 1 will be caught later.
1530                 */
1531                if (opts->new_branch && argc == 1)
1532                        die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1533                                argv[0], opts->new_branch);
1534
1535                if (opts->force_detach)
1536                        die(_("git checkout: --detach does not take a path argument '%s'"),
1537                            argv[0]);
1538
1539                if (1 < !!opts->writeout_stage + !!opts->force + !!opts->merge)
1540                        die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1541                              "checking out of the index."));
1542        }
1543
1544        if (opts->new_branch) {
1545                struct strbuf buf = STRBUF_INIT;
1546
1547                if (opts->new_branch_force)
1548                        opts->branch_exists = validate_branchname(opts->new_branch, &buf);
1549                else
1550                        opts->branch_exists =
1551                                validate_new_branchname(opts->new_branch, &buf, 0);
1552                strbuf_release(&buf);
1553        }
1554
1555        UNLEAK(opts);
1556        if (opts->patch_mode || opts->pathspec.nr) {
1557                int ret = checkout_paths(opts, new_branch_info.name);
1558                if (ret && dwim_remotes_matched > 1 &&
1559                    advice_checkout_ambiguous_remote_branch_name)
1560                        advise(_("'%s' matched more than one remote tracking branch.\n"
1561                                 "We found %d remotes with a reference that matched. So we fell back\n"
1562                                 "on trying to resolve the argument as a path, but failed there too!\n"
1563                                 "\n"
1564                                 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
1565                                 "you can do so by fully qualifying the name with the --track option:\n"
1566                                 "\n"
1567                                 "    git checkout --track origin/<name>\n"
1568                                 "\n"
1569                                 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
1570                                 "one remote, e.g. the 'origin' remote, consider setting\n"
1571                                 "checkout.defaultRemote=origin in your config."),
1572                               argv[0],
1573                               dwim_remotes_matched);
1574                return ret;
1575        } else {
1576                return checkout_branch(opts, &new_branch_info);
1577        }
1578}
1579
1580int cmd_checkout(int argc, const char **argv, const char *prefix)
1581{
1582        struct checkout_opts opts;
1583        struct option *options;
1584        struct option checkout_options[] = {
1585                OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1586                           N_("create and checkout a new branch")),
1587                OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1588                           N_("create/reset and checkout a branch")),
1589                OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1590                OPT_END()
1591        };
1592        int ret;
1593
1594        memset(&opts, 0, sizeof(opts));
1595        opts.no_dwim_new_local_branch = 0;
1596        opts.accept_pathspec = 1;
1597
1598        options = parse_options_dup(checkout_options);
1599        options = add_common_options(&opts, options);
1600        options = add_common_switch_branch_options(&opts, options);
1601        options = add_checkout_path_options(&opts, options);
1602
1603        ret = checkout_main(argc, argv, prefix, &opts,
1604                            options, checkout_usage);
1605        FREE_AND_NULL(options);
1606        return ret;
1607}
1608
1609int cmd_switch(int argc, const char **argv, const char *prefix)
1610{
1611        struct checkout_opts opts;
1612        struct option *options = NULL;
1613        struct option switch_options[] = {
1614                OPT_STRING('c', "create", &opts.new_branch, N_("branch"),
1615                           N_("create and switch to a new branch")),
1616                OPT_STRING('C', "force-create", &opts.new_branch_force, N_("branch"),
1617                           N_("create/reset and switch to a branch")),
1618                OPT_BOOL(0, "discard-changes", &opts.discard_changes,
1619                         N_("throw away local modifications")),
1620                OPT_END()
1621        };
1622        int ret;
1623
1624        memset(&opts, 0, sizeof(opts));
1625        opts.no_dwim_new_local_branch = 0;
1626        opts.accept_pathspec = 0;
1627
1628        options = parse_options_dup(switch_options);
1629        options = add_common_options(&opts, options);
1630        options = add_common_switch_branch_options(&opts, options);
1631
1632        ret = checkout_main(argc, argv, prefix, &opts,
1633                            options, switch_branch_usage);
1634        FREE_AND_NULL(options);
1635        return ret;
1636}