Andrew's git / gitweb.git / builtin/rebase.c
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builtin / rebase.con commit builtin rebase: support --force-rebase (1ed9c14)
   1/*
   2 * "git rebase" builtin command
   3 *
   4 * Copyright (c) 2018 Pratik Karki
   5 */
   6
   7#include "builtin.h"
   8#include "run-command.h"
   9#include "exec-cmd.h"
  10#include "argv-array.h"
  11#include "dir.h"
  12#include "packfile.h"
  13#include "refs.h"
  14#include "quote.h"
  15#include "config.h"
  16#include "cache-tree.h"
  17#include "unpack-trees.h"
  18#include "lockfile.h"
  19#include "parse-options.h"
  20#include "commit.h"
  21#include "diff.h"
  22#include "wt-status.h"
  23#include "revision.h"
  24
  25static char const * const builtin_rebase_usage[] = {
  26        N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  27                "[<upstream>] [<branch>]"),
  28        N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  29                "--root [<branch>]"),
  30        N_("git rebase --continue | --abort | --skip | --edit-todo"),
  31        NULL
  32};
  33
  34static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  35static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  36
  37enum rebase_type {
  38        REBASE_UNSPECIFIED = -1,
  39        REBASE_AM,
  40        REBASE_MERGE,
  41        REBASE_INTERACTIVE,
  42        REBASE_PRESERVE_MERGES
  43};
  44
  45static int use_builtin_rebase(void)
  46{
  47        struct child_process cp = CHILD_PROCESS_INIT;
  48        struct strbuf out = STRBUF_INIT;
  49        int ret;
  50
  51        argv_array_pushl(&cp.args,
  52                         "config", "--bool", "rebase.usebuiltin", NULL);
  53        cp.git_cmd = 1;
  54        if (capture_command(&cp, &out, 6)) {
  55                strbuf_release(&out);
  56                return 0;
  57        }
  58
  59        strbuf_trim(&out);
  60        ret = !strcmp("true", out.buf);
  61        strbuf_release(&out);
  62        return ret;
  63}
  64
  65static int apply_autostash(void)
  66{
  67        warning("TODO");
  68        return 0;
  69}
  70
  71struct rebase_options {
  72        enum rebase_type type;
  73        const char *state_dir;
  74        struct commit *upstream;
  75        const char *upstream_name;
  76        const char *upstream_arg;
  77        char *head_name;
  78        struct object_id orig_head;
  79        struct commit *onto;
  80        const char *onto_name;
  81        const char *revisions;
  82        int root;
  83        struct commit *restrict_revision;
  84        int dont_finish_rebase;
  85        enum {
  86                REBASE_NO_QUIET = 1<<0,
  87                REBASE_VERBOSE = 1<<1,
  88                REBASE_DIFFSTAT = 1<<2,
  89                REBASE_FORCE = 1<<3,
  90        } flags;
  91        struct strbuf git_am_opt;
  92};
  93
  94static int is_interactive(struct rebase_options *opts)
  95{
  96        return opts->type == REBASE_INTERACTIVE ||
  97                opts->type == REBASE_PRESERVE_MERGES;
  98}
  99
 100/* Returns the filename prefixed by the state_dir */
 101static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 102{
 103        static struct strbuf path = STRBUF_INIT;
 104        static size_t prefix_len;
 105
 106        if (!prefix_len) {
 107                strbuf_addf(&path, "%s/", opts->state_dir);
 108                prefix_len = path.len;
 109        }
 110
 111        strbuf_setlen(&path, prefix_len);
 112        strbuf_addstr(&path, filename);
 113        return path.buf;
 114}
 115
 116static int finish_rebase(struct rebase_options *opts)
 117{
 118        struct strbuf dir = STRBUF_INIT;
 119        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 120
 121        delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 122        apply_autostash();
 123        close_all_packs(the_repository->objects);
 124        /*
 125         * We ignore errors in 'gc --auto', since the
 126         * user should see them.
 127         */
 128        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 129        strbuf_addstr(&dir, opts->state_dir);
 130        remove_dir_recursively(&dir, 0);
 131        strbuf_release(&dir);
 132
 133        return 0;
 134}
 135
 136static struct commit *peel_committish(const char *name)
 137{
 138        struct object *obj;
 139        struct object_id oid;
 140
 141        if (get_oid(name, &oid))
 142                return NULL;
 143        obj = parse_object(the_repository, &oid);
 144        return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 145}
 146
 147static void add_var(struct strbuf *buf, const char *name, const char *value)
 148{
 149        if (!value)
 150                strbuf_addf(buf, "unset %s; ", name);
 151        else {
 152                strbuf_addf(buf, "%s=", name);
 153                sq_quote_buf(buf, value);
 154                strbuf_addstr(buf, "; ");
 155        }
 156}
 157
 158static int run_specific_rebase(struct rebase_options *opts)
 159{
 160        const char *argv[] = { NULL, NULL };
 161        struct strbuf script_snippet = STRBUF_INIT;
 162        int status;
 163        const char *backend, *backend_func;
 164
 165        add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 166        add_var(&script_snippet, "state_dir", opts->state_dir);
 167
 168        add_var(&script_snippet, "upstream_name", opts->upstream_name);
 169        add_var(&script_snippet, "upstream",
 170                                 oid_to_hex(&opts->upstream->object.oid));
 171        add_var(&script_snippet, "head_name", opts->head_name);
 172        add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 173        add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
 174        add_var(&script_snippet, "onto_name", opts->onto_name);
 175        add_var(&script_snippet, "revisions", opts->revisions);
 176        add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 177                oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 178        add_var(&script_snippet, "GIT_QUIET",
 179                opts->flags & REBASE_NO_QUIET ? "" : "t");
 180        add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 181        add_var(&script_snippet, "verbose",
 182                opts->flags & REBASE_VERBOSE ? "t" : "");
 183        add_var(&script_snippet, "diffstat",
 184                opts->flags & REBASE_DIFFSTAT ? "t" : "");
 185        add_var(&script_snippet, "force_rebase",
 186                opts->flags & REBASE_FORCE ? "t" : "");
 187
 188        switch (opts->type) {
 189        case REBASE_AM:
 190                backend = "git-rebase--am";
 191                backend_func = "git_rebase__am";
 192                break;
 193        case REBASE_INTERACTIVE:
 194                backend = "git-rebase--interactive";
 195                backend_func = "git_rebase__interactive";
 196                break;
 197        case REBASE_MERGE:
 198                backend = "git-rebase--merge";
 199                backend_func = "git_rebase__merge";
 200                break;
 201        case REBASE_PRESERVE_MERGES:
 202                backend = "git-rebase--preserve-merges";
 203                backend_func = "git_rebase__preserve_merges";
 204                break;
 205        default:
 206                BUG("Unhandled rebase type %d", opts->type);
 207                break;
 208        }
 209
 210        strbuf_addf(&script_snippet,
 211                    ". git-sh-setup && . git-rebase--common &&"
 212                    " . %s && %s", backend, backend_func);
 213        argv[0] = script_snippet.buf;
 214
 215        status = run_command_v_opt(argv, RUN_USING_SHELL);
 216        if (opts->dont_finish_rebase)
 217                ; /* do nothing */
 218        else if (status == 0) {
 219                if (!file_exists(state_dir_path("stopped-sha", opts)))
 220                        finish_rebase(opts);
 221        } else if (status == 2) {
 222                struct strbuf dir = STRBUF_INIT;
 223
 224                apply_autostash();
 225                strbuf_addstr(&dir, opts->state_dir);
 226                remove_dir_recursively(&dir, 0);
 227                strbuf_release(&dir);
 228                die("Nothing to do");
 229        }
 230
 231        strbuf_release(&script_snippet);
 232
 233        return status ? -1 : 0;
 234}
 235
 236#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 237
 238static int reset_head(struct object_id *oid, const char *action,
 239                      const char *switch_to_branch, int detach_head)
 240{
 241        struct object_id head_oid;
 242        struct tree_desc desc;
 243        struct lock_file lock = LOCK_INIT;
 244        struct unpack_trees_options unpack_tree_opts;
 245        struct tree *tree;
 246        const char *reflog_action;
 247        struct strbuf msg = STRBUF_INIT;
 248        size_t prefix_len;
 249        struct object_id *orig = NULL, oid_orig,
 250                *old_orig = NULL, oid_old_orig;
 251        int ret = 0;
 252
 253        if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 254                return -1;
 255
 256        if (!oid) {
 257                if (get_oid("HEAD", &head_oid)) {
 258                        rollback_lock_file(&lock);
 259                        return error(_("could not determine HEAD revision"));
 260                }
 261                oid = &head_oid;
 262        }
 263
 264        memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 265        setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 266        unpack_tree_opts.head_idx = 1;
 267        unpack_tree_opts.src_index = the_repository->index;
 268        unpack_tree_opts.dst_index = the_repository->index;
 269        unpack_tree_opts.fn = oneway_merge;
 270        unpack_tree_opts.update = 1;
 271        unpack_tree_opts.merge = 1;
 272        if (!detach_head)
 273                unpack_tree_opts.reset = 1;
 274
 275        if (read_index_unmerged(the_repository->index) < 0) {
 276                rollback_lock_file(&lock);
 277                return error(_("could not read index"));
 278        }
 279
 280        if (!fill_tree_descriptor(&desc, oid)) {
 281                error(_("failed to find tree of %s"), oid_to_hex(oid));
 282                rollback_lock_file(&lock);
 283                free((void *)desc.buffer);
 284                return -1;
 285        }
 286
 287        if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 288                rollback_lock_file(&lock);
 289                free((void *)desc.buffer);
 290                return -1;
 291        }
 292
 293        tree = parse_tree_indirect(oid);
 294        prime_cache_tree(the_repository->index, tree);
 295
 296        if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 297                ret = error(_("could not write index"));
 298        free((void *)desc.buffer);
 299
 300        if (ret)
 301                return ret;
 302
 303        reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 304        strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 305        prefix_len = msg.len;
 306
 307        if (!get_oid("ORIG_HEAD", &oid_old_orig))
 308                old_orig = &oid_old_orig;
 309        if (!get_oid("HEAD", &oid_orig)) {
 310                orig = &oid_orig;
 311                strbuf_addstr(&msg, "updating ORIG_HEAD");
 312                update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 313                           UPDATE_REFS_MSG_ON_ERR);
 314        } else if (old_orig)
 315                delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 316        strbuf_setlen(&msg, prefix_len);
 317        strbuf_addstr(&msg, "updating HEAD");
 318        if (!switch_to_branch)
 319                ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
 320                                 UPDATE_REFS_MSG_ON_ERR);
 321        else {
 322                ret = create_symref("HEAD", switch_to_branch, msg.buf);
 323                if (!ret)
 324                        ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
 325                                         UPDATE_REFS_MSG_ON_ERR);
 326        }
 327
 328        strbuf_release(&msg);
 329        return ret;
 330}
 331
 332static int rebase_config(const char *var, const char *value, void *data)
 333{
 334        struct rebase_options *opts = data;
 335
 336        if (!strcmp(var, "rebase.stat")) {
 337                if (git_config_bool(var, value))
 338                        opts->flags |= REBASE_DIFFSTAT;
 339                else
 340                        opts->flags &= !REBASE_DIFFSTAT;
 341                return 0;
 342        }
 343
 344        return git_default_config(var, value, data);
 345}
 346
 347/*
 348 * Determines whether the commits in from..to are linear, i.e. contain
 349 * no merge commits. This function *expects* `from` to be an ancestor of
 350 * `to`.
 351 */
 352static int is_linear_history(struct commit *from, struct commit *to)
 353{
 354        while (to && to != from) {
 355                parse_commit(to);
 356                if (!to->parents)
 357                        return 1;
 358                if (to->parents->next)
 359                        return 0;
 360                to = to->parents->item;
 361        }
 362        return 1;
 363}
 364
 365static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 366                            struct object_id *merge_base)
 367{
 368        struct commit *head = lookup_commit(the_repository, head_oid);
 369        struct commit_list *merge_bases;
 370        int res;
 371
 372        if (!head)
 373                return 0;
 374
 375        merge_bases = get_merge_bases(onto, head);
 376        if (merge_bases && !merge_bases->next) {
 377                oidcpy(merge_base, &merge_bases->item->object.oid);
 378                res = !oidcmp(merge_base, &onto->object.oid);
 379        } else {
 380                oidcpy(merge_base, &null_oid);
 381                res = 0;
 382        }
 383        free_commit_list(merge_bases);
 384        return res && is_linear_history(onto, head);
 385}
 386
 387int cmd_rebase(int argc, const char **argv, const char *prefix)
 388{
 389        struct rebase_options options = {
 390                .type = REBASE_UNSPECIFIED,
 391                .flags = REBASE_NO_QUIET,
 392                .git_am_opt = STRBUF_INIT,
 393        };
 394        const char *branch_name;
 395        int ret, flags;
 396        int ok_to_skip_pre_rebase = 0;
 397        struct strbuf msg = STRBUF_INIT;
 398        struct strbuf revisions = STRBUF_INIT;
 399        struct object_id merge_base;
 400        struct option builtin_rebase_options[] = {
 401                OPT_STRING(0, "onto", &options.onto_name,
 402                           N_("revision"),
 403                           N_("rebase onto given branch instead of upstream")),
 404                OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 405                         N_("allow pre-rebase hook to run")),
 406                OPT_NEGBIT('q', "quiet", &options.flags,
 407                           N_("be quiet. implies --no-stat"),
 408                           REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 409                OPT_BIT('v', "verbose", &options.flags,
 410                        N_("display a diffstat of what changed upstream"),
 411                        REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 412                {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 413                        N_("do not show diffstat of what changed upstream"),
 414                        PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 415                OPT_BIT('f', "force-rebase", &options.flags,
 416                        N_("cherry-pick all commits, even if unchanged"),
 417                        REBASE_FORCE),
 418                OPT_BIT(0, "no-ff", &options.flags,
 419                        N_("cherry-pick all commits, even if unchanged"),
 420                        REBASE_FORCE),
 421                OPT_END(),
 422        };
 423
 424        /*
 425         * NEEDSWORK: Once the builtin rebase has been tested enough
 426         * and git-legacy-rebase.sh is retired to contrib/, this preamble
 427         * can be removed.
 428         */
 429
 430        if (!use_builtin_rebase()) {
 431                const char *path = mkpath("%s/git-legacy-rebase",
 432                                          git_exec_path());
 433
 434                if (sane_execvp(path, (char **)argv) < 0)
 435                        die_errno(_("could not exec %s"), path);
 436                else
 437                        BUG("sane_execvp() returned???");
 438        }
 439
 440        if (argc == 2 && !strcmp(argv[1], "-h"))
 441                usage_with_options(builtin_rebase_usage,
 442                                   builtin_rebase_options);
 443
 444        prefix = setup_git_directory();
 445        trace_repo_setup(prefix);
 446        setup_work_tree();
 447
 448        git_config(rebase_config, &options);
 449
 450        argc = parse_options(argc, argv, prefix,
 451                             builtin_rebase_options,
 452                             builtin_rebase_usage, 0);
 453
 454        if (argc > 2)
 455                usage_with_options(builtin_rebase_usage,
 456                                   builtin_rebase_options);
 457
 458        if (!(options.flags & REBASE_NO_QUIET))
 459                strbuf_addstr(&options.git_am_opt, " -q");
 460
 461        switch (options.type) {
 462        case REBASE_MERGE:
 463        case REBASE_INTERACTIVE:
 464        case REBASE_PRESERVE_MERGES:
 465                options.state_dir = merge_dir();
 466                break;
 467        case REBASE_AM:
 468                options.state_dir = apply_dir();
 469                break;
 470        default:
 471                /* the default rebase backend is `--am` */
 472                options.type = REBASE_AM;
 473                options.state_dir = apply_dir();
 474                break;
 475        }
 476
 477        if (!options.root) {
 478                if (argc < 1)
 479                        die("TODO: handle @{upstream}");
 480                else {
 481                        options.upstream_name = argv[0];
 482                        argc--;
 483                        argv++;
 484                        if (!strcmp(options.upstream_name, "-"))
 485                                options.upstream_name = "@{-1}";
 486                }
 487                options.upstream = peel_committish(options.upstream_name);
 488                if (!options.upstream)
 489                        die(_("invalid upstream '%s'"), options.upstream_name);
 490                options.upstream_arg = options.upstream_name;
 491        } else
 492                die("TODO: upstream for --root");
 493
 494        /* Make sure the branch to rebase onto is valid. */
 495        if (!options.onto_name)
 496                options.onto_name = options.upstream_name;
 497        if (strstr(options.onto_name, "...")) {
 498                if (get_oid_mb(options.onto_name, &merge_base) < 0)
 499                        die(_("'%s': need exactly one merge base"),
 500                            options.onto_name);
 501                options.onto = lookup_commit_or_die(&merge_base,
 502                                                    options.onto_name);
 503        } else {
 504                options.onto = peel_committish(options.onto_name);
 505                if (!options.onto)
 506                        die(_("Does not point to a valid commit '%s'"),
 507                                options.onto_name);
 508        }
 509
 510        /*
 511         * If the branch to rebase is given, that is the branch we will rebase
 512         * branch_name -- branch/commit being rebased, or
 513         *                HEAD (already detached)
 514         * orig_head -- commit object name of tip of the branch before rebasing
 515         * head_name -- refs/heads/<that-branch> or "detached HEAD"
 516         */
 517        if (argc > 0)
 518                 die("TODO: handle switch_to");
 519        else {
 520                /* Do not need to switch branches, we are already on it. */
 521                options.head_name =
 522                        xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
 523                                         &flags));
 524                if (!options.head_name)
 525                        die(_("No such ref: %s"), "HEAD");
 526                if (flags & REF_ISSYMREF) {
 527                        if (!skip_prefix(options.head_name,
 528                                         "refs/heads/", &branch_name))
 529                                branch_name = options.head_name;
 530
 531                } else {
 532                        options.head_name = xstrdup("detached HEAD");
 533                        branch_name = "HEAD";
 534                }
 535                if (get_oid("HEAD", &options.orig_head))
 536                        die(_("Could not resolve HEAD to a revision"));
 537        }
 538
 539        if (read_index(the_repository->index) < 0)
 540                die(_("could not read index"));
 541
 542        if (require_clean_work_tree("rebase",
 543                                    _("Please commit or stash them."), 1, 1)) {
 544                ret = 1;
 545                goto cleanup;
 546        }
 547
 548        /*
 549         * Now we are rebasing commits upstream..orig_head (or with --root,
 550         * everything leading up to orig_head) on top of onto.
 551         */
 552
 553        /*
 554         * Check if we are already based on onto with linear history,
 555         * but this should be done only when upstream and onto are the same
 556         * and if this is not an interactive rebase.
 557         */
 558        if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
 559            !is_interactive(&options) && !options.restrict_revision &&
 560            !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
 561                int flag;
 562
 563                if (!(options.flags & REBASE_FORCE)) {
 564                        if (!(options.flags & REBASE_NO_QUIET))
 565                                ; /* be quiet */
 566                        else if (!strcmp(branch_name, "HEAD") &&
 567                                 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 568                                puts(_("HEAD is up to date."));
 569                        else
 570                                printf(_("Current branch %s is up to date.\n"),
 571                                       branch_name);
 572                        ret = !!finish_rebase(&options);
 573                        goto cleanup;
 574                } else if (!(options.flags & REBASE_NO_QUIET))
 575                        ; /* be quiet */
 576                else if (!strcmp(branch_name, "HEAD") &&
 577                         resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 578                        puts(_("HEAD is up to date, rebase forced."));
 579                else
 580                        printf(_("Current branch %s is up to date, rebase "
 581                                 "forced.\n"), branch_name);
 582        }
 583
 584        /* If a hook exists, give it a chance to interrupt*/
 585        if (!ok_to_skip_pre_rebase &&
 586            run_hook_le(NULL, "pre-rebase", options.upstream_arg,
 587                        argc ? argv[0] : NULL, NULL))
 588                die(_("The pre-rebase hook refused to rebase."));
 589
 590        if (options.flags & REBASE_DIFFSTAT) {
 591                struct diff_options opts;
 592
 593                if (options.flags & REBASE_VERBOSE)
 594                        printf(_("Changes from %s to %s:\n"),
 595                                oid_to_hex(&merge_base),
 596                                oid_to_hex(&options.onto->object.oid));
 597
 598                /* We want color (if set), but no pager */
 599                diff_setup(&opts);
 600                opts.stat_width = -1; /* use full terminal width */
 601                opts.stat_graph_width = -1; /* respect statGraphWidth config */
 602                opts.output_format |=
 603                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 604                opts.detect_rename = DIFF_DETECT_RENAME;
 605                diff_setup_done(&opts);
 606                diff_tree_oid(&merge_base, &options.onto->object.oid,
 607                              "", &opts);
 608                diffcore_std(&opts);
 609                diff_flush(&opts);
 610        }
 611
 612        /* Detach HEAD and reset the tree */
 613        if (options.flags & REBASE_NO_QUIET)
 614                printf(_("First, rewinding head to replay your work on top of "
 615                         "it...\n"));
 616
 617        strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
 618        if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
 619                die(_("Could not detach HEAD"));
 620        strbuf_release(&msg);
 621
 622        strbuf_addf(&revisions, "%s..%s",
 623                    options.root ? oid_to_hex(&options.onto->object.oid) :
 624                    (options.restrict_revision ?
 625                     oid_to_hex(&options.restrict_revision->object.oid) :
 626                     oid_to_hex(&options.upstream->object.oid)),
 627                    oid_to_hex(&options.orig_head));
 628
 629        options.revisions = revisions.buf;
 630
 631        ret = !!run_specific_rebase(&options);
 632
 633cleanup:
 634        strbuf_release(&revisions);
 635        free(options.head_name);
 636        return ret;
 637}