builtin / rebase.con commit builtin rebase: support --root (9dba809)
   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#include "rerere.h"
  25
  26static char const * const builtin_rebase_usage[] = {
  27        N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  28                "[<upstream>] [<branch>]"),
  29        N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  30                "--root [<branch>]"),
  31        N_("git rebase --continue | --abort | --skip | --edit-todo"),
  32        NULL
  33};
  34
  35static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  36static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  37
  38enum rebase_type {
  39        REBASE_UNSPECIFIED = -1,
  40        REBASE_AM,
  41        REBASE_MERGE,
  42        REBASE_INTERACTIVE,
  43        REBASE_PRESERVE_MERGES
  44};
  45
  46static int use_builtin_rebase(void)
  47{
  48        struct child_process cp = CHILD_PROCESS_INIT;
  49        struct strbuf out = STRBUF_INIT;
  50        int ret;
  51
  52        argv_array_pushl(&cp.args,
  53                         "config", "--bool", "rebase.usebuiltin", NULL);
  54        cp.git_cmd = 1;
  55        if (capture_command(&cp, &out, 6)) {
  56                strbuf_release(&out);
  57                return 0;
  58        }
  59
  60        strbuf_trim(&out);
  61        ret = !strcmp("true", out.buf);
  62        strbuf_release(&out);
  63        return ret;
  64}
  65
  66struct rebase_options {
  67        enum rebase_type type;
  68        const char *state_dir;
  69        struct commit *upstream;
  70        const char *upstream_name;
  71        const char *upstream_arg;
  72        char *head_name;
  73        struct object_id orig_head;
  74        struct commit *onto;
  75        const char *onto_name;
  76        const char *revisions;
  77        const char *switch_to;
  78        int root;
  79        struct object_id *squash_onto;
  80        struct commit *restrict_revision;
  81        int dont_finish_rebase;
  82        enum {
  83                REBASE_NO_QUIET = 1<<0,
  84                REBASE_VERBOSE = 1<<1,
  85                REBASE_DIFFSTAT = 1<<2,
  86                REBASE_FORCE = 1<<3,
  87                REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  88        } flags;
  89        struct strbuf git_am_opt;
  90        const char *action;
  91        int signoff;
  92        int allow_rerere_autoupdate;
  93        int keep_empty;
  94        int autosquash;
  95        char *gpg_sign_opt;
  96        int autostash;
  97        char *cmd;
  98        int allow_empty_message;
  99        int rebase_merges, rebase_cousins;
 100        char *strategy, *strategy_opts;
 101};
 102
 103static int is_interactive(struct rebase_options *opts)
 104{
 105        return opts->type == REBASE_INTERACTIVE ||
 106                opts->type == REBASE_PRESERVE_MERGES;
 107}
 108
 109static void imply_interactive(struct rebase_options *opts, const char *option)
 110{
 111        switch (opts->type) {
 112        case REBASE_AM:
 113                die(_("%s requires an interactive rebase"), option);
 114                break;
 115        case REBASE_INTERACTIVE:
 116        case REBASE_PRESERVE_MERGES:
 117                break;
 118        case REBASE_MERGE:
 119                /* we silently *upgrade* --merge to --interactive if needed */
 120        default:
 121                opts->type = REBASE_INTERACTIVE; /* implied */
 122                break;
 123        }
 124}
 125
 126/* Returns the filename prefixed by the state_dir */
 127static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 128{
 129        static struct strbuf path = STRBUF_INIT;
 130        static size_t prefix_len;
 131
 132        if (!prefix_len) {
 133                strbuf_addf(&path, "%s/", opts->state_dir);
 134                prefix_len = path.len;
 135        }
 136
 137        strbuf_setlen(&path, prefix_len);
 138        strbuf_addstr(&path, filename);
 139        return path.buf;
 140}
 141
 142/* Read one file, then strip line endings */
 143static int read_one(const char *path, struct strbuf *buf)
 144{
 145        if (strbuf_read_file(buf, path, 0) < 0)
 146                return error_errno(_("could not read '%s'"), path);
 147        strbuf_trim_trailing_newline(buf);
 148        return 0;
 149}
 150
 151/* Initialize the rebase options from the state directory. */
 152static int read_basic_state(struct rebase_options *opts)
 153{
 154        struct strbuf head_name = STRBUF_INIT;
 155        struct strbuf buf = STRBUF_INIT;
 156        struct object_id oid;
 157
 158        if (read_one(state_dir_path("head-name", opts), &head_name) ||
 159            read_one(state_dir_path("onto", opts), &buf))
 160                return -1;
 161        opts->head_name = starts_with(head_name.buf, "refs/") ?
 162                xstrdup(head_name.buf) : NULL;
 163        strbuf_release(&head_name);
 164        if (get_oid(buf.buf, &oid))
 165                return error(_("could not get 'onto': '%s'"), buf.buf);
 166        opts->onto = lookup_commit_or_die(&oid, buf.buf);
 167
 168        /*
 169         * We always write to orig-head, but interactive rebase used to write to
 170         * head. Fall back to reading from head to cover for the case that the
 171         * user upgraded git with an ongoing interactive rebase.
 172         */
 173        strbuf_reset(&buf);
 174        if (file_exists(state_dir_path("orig-head", opts))) {
 175                if (read_one(state_dir_path("orig-head", opts), &buf))
 176                        return -1;
 177        } else if (read_one(state_dir_path("head", opts), &buf))
 178                return -1;
 179        if (get_oid(buf.buf, &opts->orig_head))
 180                return error(_("invalid orig-head: '%s'"), buf.buf);
 181
 182        strbuf_reset(&buf);
 183        if (read_one(state_dir_path("quiet", opts), &buf))
 184                return -1;
 185        if (buf.len)
 186                opts->flags &= ~REBASE_NO_QUIET;
 187        else
 188                opts->flags |= REBASE_NO_QUIET;
 189
 190        if (file_exists(state_dir_path("verbose", opts)))
 191                opts->flags |= REBASE_VERBOSE;
 192
 193        if (file_exists(state_dir_path("signoff", opts))) {
 194                opts->signoff = 1;
 195                opts->flags |= REBASE_FORCE;
 196        }
 197
 198        if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 199                strbuf_reset(&buf);
 200                if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
 201                            &buf))
 202                        return -1;
 203                if (!strcmp(buf.buf, "--rerere-autoupdate"))
 204                        opts->allow_rerere_autoupdate = 1;
 205                else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 206                        opts->allow_rerere_autoupdate = 0;
 207                else
 208                        warning(_("ignoring invalid allow_rerere_autoupdate: "
 209                                  "'%s'"), buf.buf);
 210        } else
 211                opts->allow_rerere_autoupdate = -1;
 212
 213        if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 214                strbuf_reset(&buf);
 215                if (read_one(state_dir_path("gpg_sign_opt", opts),
 216                            &buf))
 217                        return -1;
 218                free(opts->gpg_sign_opt);
 219                opts->gpg_sign_opt = xstrdup(buf.buf);
 220        }
 221
 222        if (file_exists(state_dir_path("strategy", opts))) {
 223                strbuf_reset(&buf);
 224                if (read_one(state_dir_path("strategy", opts), &buf))
 225                        return -1;
 226                free(opts->strategy);
 227                opts->strategy = xstrdup(buf.buf);
 228        }
 229
 230        if (file_exists(state_dir_path("strategy_opts", opts))) {
 231                strbuf_reset(&buf);
 232                if (read_one(state_dir_path("strategy_opts", opts), &buf))
 233                        return -1;
 234                free(opts->strategy_opts);
 235                opts->strategy_opts = xstrdup(buf.buf);
 236        }
 237
 238        strbuf_release(&buf);
 239
 240        return 0;
 241}
 242
 243static int apply_autostash(struct rebase_options *opts)
 244{
 245        const char *path = state_dir_path("autostash", opts);
 246        struct strbuf autostash = STRBUF_INIT;
 247        struct child_process stash_apply = CHILD_PROCESS_INIT;
 248
 249        if (!file_exists(path))
 250                return 0;
 251
 252        if (read_one(state_dir_path("autostash", opts), &autostash))
 253                return error(_("Could not read '%s'"), path);
 254        argv_array_pushl(&stash_apply.args,
 255                         "stash", "apply", autostash.buf, NULL);
 256        stash_apply.git_cmd = 1;
 257        stash_apply.no_stderr = stash_apply.no_stdout =
 258                stash_apply.no_stdin = 1;
 259        if (!run_command(&stash_apply))
 260                printf(_("Applied autostash.\n"));
 261        else {
 262                struct argv_array args = ARGV_ARRAY_INIT;
 263                int res = 0;
 264
 265                argv_array_pushl(&args,
 266                                 "stash", "store", "-m", "autostash", "-q",
 267                                 autostash.buf, NULL);
 268                if (run_command_v_opt(args.argv, RUN_GIT_CMD))
 269                        res = error(_("Cannot store %s"), autostash.buf);
 270                argv_array_clear(&args);
 271                strbuf_release(&autostash);
 272                if (res)
 273                        return res;
 274
 275                fprintf(stderr,
 276                        _("Applying autostash resulted in conflicts.\n"
 277                          "Your changes are safe in the stash.\n"
 278                          "You can run \"git stash pop\" or \"git stash drop\" "
 279                          "at any time.\n"));
 280        }
 281
 282        strbuf_release(&autostash);
 283        return 0;
 284}
 285
 286static int finish_rebase(struct rebase_options *opts)
 287{
 288        struct strbuf dir = STRBUF_INIT;
 289        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 290
 291        delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 292        apply_autostash(opts);
 293        close_all_packs(the_repository->objects);
 294        /*
 295         * We ignore errors in 'gc --auto', since the
 296         * user should see them.
 297         */
 298        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 299        strbuf_addstr(&dir, opts->state_dir);
 300        remove_dir_recursively(&dir, 0);
 301        strbuf_release(&dir);
 302
 303        return 0;
 304}
 305
 306static struct commit *peel_committish(const char *name)
 307{
 308        struct object *obj;
 309        struct object_id oid;
 310
 311        if (get_oid(name, &oid))
 312                return NULL;
 313        obj = parse_object(the_repository, &oid);
 314        return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 315}
 316
 317static void add_var(struct strbuf *buf, const char *name, const char *value)
 318{
 319        if (!value)
 320                strbuf_addf(buf, "unset %s; ", name);
 321        else {
 322                strbuf_addf(buf, "%s=", name);
 323                sq_quote_buf(buf, value);
 324                strbuf_addstr(buf, "; ");
 325        }
 326}
 327
 328static int run_specific_rebase(struct rebase_options *opts)
 329{
 330        const char *argv[] = { NULL, NULL };
 331        struct strbuf script_snippet = STRBUF_INIT;
 332        int status;
 333        const char *backend, *backend_func;
 334
 335        add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 336        add_var(&script_snippet, "state_dir", opts->state_dir);
 337
 338        add_var(&script_snippet, "upstream_name", opts->upstream_name);
 339        add_var(&script_snippet, "upstream", opts->upstream ?
 340                oid_to_hex(&opts->upstream->object.oid) : NULL);
 341        add_var(&script_snippet, "head_name",
 342                opts->head_name ? opts->head_name : "detached HEAD");
 343        add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 344        add_var(&script_snippet, "onto", opts->onto ?
 345                oid_to_hex(&opts->onto->object.oid) : NULL);
 346        add_var(&script_snippet, "onto_name", opts->onto_name);
 347        add_var(&script_snippet, "revisions", opts->revisions);
 348        add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 349                oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 350        add_var(&script_snippet, "GIT_QUIET",
 351                opts->flags & REBASE_NO_QUIET ? "" : "t");
 352        add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 353        add_var(&script_snippet, "verbose",
 354                opts->flags & REBASE_VERBOSE ? "t" : "");
 355        add_var(&script_snippet, "diffstat",
 356                opts->flags & REBASE_DIFFSTAT ? "t" : "");
 357        add_var(&script_snippet, "force_rebase",
 358                opts->flags & REBASE_FORCE ? "t" : "");
 359        if (opts->switch_to)
 360                add_var(&script_snippet, "switch_to", opts->switch_to);
 361        add_var(&script_snippet, "action", opts->action ? opts->action : "");
 362        add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 363        add_var(&script_snippet, "allow_rerere_autoupdate",
 364                opts->allow_rerere_autoupdate < 0 ? "" :
 365                opts->allow_rerere_autoupdate ?
 366                "--rerere-autoupdate" : "--no-rerere-autoupdate");
 367        add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 368        add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 369        add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 370        add_var(&script_snippet, "cmd", opts->cmd);
 371        add_var(&script_snippet, "allow_empty_message",
 372                opts->allow_empty_message ?  "--allow-empty-message" : "");
 373        add_var(&script_snippet, "rebase_merges",
 374                opts->rebase_merges ? "t" : "");
 375        add_var(&script_snippet, "rebase_cousins",
 376                opts->rebase_cousins ? "t" : "");
 377        add_var(&script_snippet, "strategy", opts->strategy);
 378        add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
 379        add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
 380        add_var(&script_snippet, "squash_onto",
 381                opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
 382
 383        switch (opts->type) {
 384        case REBASE_AM:
 385                backend = "git-rebase--am";
 386                backend_func = "git_rebase__am";
 387                break;
 388        case REBASE_INTERACTIVE:
 389                backend = "git-rebase--interactive";
 390                backend_func = "git_rebase__interactive";
 391                break;
 392        case REBASE_MERGE:
 393                backend = "git-rebase--merge";
 394                backend_func = "git_rebase__merge";
 395                break;
 396        case REBASE_PRESERVE_MERGES:
 397                backend = "git-rebase--preserve-merges";
 398                backend_func = "git_rebase__preserve_merges";
 399                break;
 400        default:
 401                BUG("Unhandled rebase type %d", opts->type);
 402                break;
 403        }
 404
 405        strbuf_addf(&script_snippet,
 406                    ". git-sh-setup && . git-rebase--common &&"
 407                    " . %s && %s", backend, backend_func);
 408        argv[0] = script_snippet.buf;
 409
 410        status = run_command_v_opt(argv, RUN_USING_SHELL);
 411        if (opts->dont_finish_rebase)
 412                ; /* do nothing */
 413        else if (status == 0) {
 414                if (!file_exists(state_dir_path("stopped-sha", opts)))
 415                        finish_rebase(opts);
 416        } else if (status == 2) {
 417                struct strbuf dir = STRBUF_INIT;
 418
 419                apply_autostash(opts);
 420                strbuf_addstr(&dir, opts->state_dir);
 421                remove_dir_recursively(&dir, 0);
 422                strbuf_release(&dir);
 423                die("Nothing to do");
 424        }
 425
 426        strbuf_release(&script_snippet);
 427
 428        return status ? -1 : 0;
 429}
 430
 431#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 432
 433static int reset_head(struct object_id *oid, const char *action,
 434                      const char *switch_to_branch, int detach_head)
 435{
 436        struct object_id head_oid;
 437        struct tree_desc desc;
 438        struct lock_file lock = LOCK_INIT;
 439        struct unpack_trees_options unpack_tree_opts;
 440        struct tree *tree;
 441        const char *reflog_action;
 442        struct strbuf msg = STRBUF_INIT;
 443        size_t prefix_len;
 444        struct object_id *orig = NULL, oid_orig,
 445                *old_orig = NULL, oid_old_orig;
 446        int ret = 0;
 447
 448        if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 449                BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 450
 451        if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 452                return -1;
 453
 454        if (!oid) {
 455                if (get_oid("HEAD", &head_oid)) {
 456                        rollback_lock_file(&lock);
 457                        return error(_("could not determine HEAD revision"));
 458                }
 459                oid = &head_oid;
 460        }
 461
 462        memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 463        setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 464        unpack_tree_opts.head_idx = 1;
 465        unpack_tree_opts.src_index = the_repository->index;
 466        unpack_tree_opts.dst_index = the_repository->index;
 467        unpack_tree_opts.fn = oneway_merge;
 468        unpack_tree_opts.update = 1;
 469        unpack_tree_opts.merge = 1;
 470        if (!detach_head)
 471                unpack_tree_opts.reset = 1;
 472
 473        if (read_index_unmerged(the_repository->index) < 0) {
 474                rollback_lock_file(&lock);
 475                return error(_("could not read index"));
 476        }
 477
 478        if (!fill_tree_descriptor(&desc, oid)) {
 479                error(_("failed to find tree of %s"), oid_to_hex(oid));
 480                rollback_lock_file(&lock);
 481                free((void *)desc.buffer);
 482                return -1;
 483        }
 484
 485        if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 486                rollback_lock_file(&lock);
 487                free((void *)desc.buffer);
 488                return -1;
 489        }
 490
 491        tree = parse_tree_indirect(oid);
 492        prime_cache_tree(the_repository->index, tree);
 493
 494        if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 495                ret = error(_("could not write index"));
 496        free((void *)desc.buffer);
 497
 498        if (ret)
 499                return ret;
 500
 501        reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 502        strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 503        prefix_len = msg.len;
 504
 505        if (!get_oid("ORIG_HEAD", &oid_old_orig))
 506                old_orig = &oid_old_orig;
 507        if (!get_oid("HEAD", &oid_orig)) {
 508                orig = &oid_orig;
 509                strbuf_addstr(&msg, "updating ORIG_HEAD");
 510                update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 511                           UPDATE_REFS_MSG_ON_ERR);
 512        } else if (old_orig)
 513                delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 514        strbuf_setlen(&msg, prefix_len);
 515        strbuf_addstr(&msg, "updating HEAD");
 516        if (!switch_to_branch)
 517                ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
 518                                 UPDATE_REFS_MSG_ON_ERR);
 519        else {
 520                ret = create_symref("HEAD", switch_to_branch, msg.buf);
 521                if (!ret)
 522                        ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
 523                                         UPDATE_REFS_MSG_ON_ERR);
 524        }
 525
 526        strbuf_release(&msg);
 527        return ret;
 528}
 529
 530static int rebase_config(const char *var, const char *value, void *data)
 531{
 532        struct rebase_options *opts = data;
 533
 534        if (!strcmp(var, "rebase.stat")) {
 535                if (git_config_bool(var, value))
 536                        opts->flags |= REBASE_DIFFSTAT;
 537                else
 538                        opts->flags &= !REBASE_DIFFSTAT;
 539                return 0;
 540        }
 541
 542        if (!strcmp(var, "rebase.autosquash")) {
 543                opts->autosquash = git_config_bool(var, value);
 544                return 0;
 545        }
 546
 547        if (!strcmp(var, "commit.gpgsign")) {
 548                free(opts->gpg_sign_opt);
 549                opts->gpg_sign_opt = git_config_bool(var, value) ?
 550                        xstrdup("-S") : NULL;
 551                return 0;
 552        }
 553
 554        if (!strcmp(var, "rebase.autostash")) {
 555                opts->autostash = git_config_bool(var, value);
 556                return 0;
 557        }
 558
 559        return git_default_config(var, value, data);
 560}
 561
 562/*
 563 * Determines whether the commits in from..to are linear, i.e. contain
 564 * no merge commits. This function *expects* `from` to be an ancestor of
 565 * `to`.
 566 */
 567static int is_linear_history(struct commit *from, struct commit *to)
 568{
 569        while (to && to != from) {
 570                parse_commit(to);
 571                if (!to->parents)
 572                        return 1;
 573                if (to->parents->next)
 574                        return 0;
 575                to = to->parents->item;
 576        }
 577        return 1;
 578}
 579
 580static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 581                            struct object_id *merge_base)
 582{
 583        struct commit *head = lookup_commit(the_repository, head_oid);
 584        struct commit_list *merge_bases;
 585        int res;
 586
 587        if (!head)
 588                return 0;
 589
 590        merge_bases = get_merge_bases(onto, head);
 591        if (merge_bases && !merge_bases->next) {
 592                oidcpy(merge_base, &merge_bases->item->object.oid);
 593                res = !oidcmp(merge_base, &onto->object.oid);
 594        } else {
 595                oidcpy(merge_base, &null_oid);
 596                res = 0;
 597        }
 598        free_commit_list(merge_bases);
 599        return res && is_linear_history(onto, head);
 600}
 601
 602/* -i followed by -m is still -i */
 603static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 604{
 605        struct rebase_options *opts = opt->value;
 606
 607        if (!is_interactive(opts))
 608                opts->type = REBASE_MERGE;
 609
 610        return 0;
 611}
 612
 613/* -i followed by -p is still explicitly interactive, but -p alone is not */
 614static int parse_opt_interactive(const struct option *opt, const char *arg,
 615                                 int unset)
 616{
 617        struct rebase_options *opts = opt->value;
 618
 619        opts->type = REBASE_INTERACTIVE;
 620        opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 621
 622        return 0;
 623}
 624
 625int cmd_rebase(int argc, const char **argv, const char *prefix)
 626{
 627        struct rebase_options options = {
 628                .type = REBASE_UNSPECIFIED,
 629                .flags = REBASE_NO_QUIET,
 630                .git_am_opt = STRBUF_INIT,
 631                .allow_rerere_autoupdate  = -1,
 632                .allow_empty_message = 1,
 633        };
 634        const char *branch_name;
 635        int ret, flags, total_argc, in_progress = 0;
 636        int ok_to_skip_pre_rebase = 0;
 637        struct strbuf msg = STRBUF_INIT;
 638        struct strbuf revisions = STRBUF_INIT;
 639        struct strbuf buf = STRBUF_INIT;
 640        struct object_id merge_base;
 641        enum {
 642                NO_ACTION,
 643                ACTION_CONTINUE,
 644                ACTION_SKIP,
 645                ACTION_ABORT,
 646                ACTION_QUIT,
 647                ACTION_EDIT_TODO,
 648                ACTION_SHOW_CURRENT_PATCH,
 649        } action = NO_ACTION;
 650        int committer_date_is_author_date = 0;
 651        int ignore_date = 0;
 652        int ignore_whitespace = 0;
 653        const char *gpg_sign = NULL;
 654        int opt_c = -1;
 655        struct string_list whitespace = STRING_LIST_INIT_NODUP;
 656        struct string_list exec = STRING_LIST_INIT_NODUP;
 657        const char *rebase_merges = NULL;
 658        int fork_point = -1;
 659        struct string_list strategy_options = STRING_LIST_INIT_NODUP;
 660        struct object_id squash_onto;
 661        char *squash_onto_name = NULL;
 662        struct option builtin_rebase_options[] = {
 663                OPT_STRING(0, "onto", &options.onto_name,
 664                           N_("revision"),
 665                           N_("rebase onto given branch instead of upstream")),
 666                OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 667                         N_("allow pre-rebase hook to run")),
 668                OPT_NEGBIT('q', "quiet", &options.flags,
 669                           N_("be quiet. implies --no-stat"),
 670                           REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 671                OPT_BIT('v', "verbose", &options.flags,
 672                        N_("display a diffstat of what changed upstream"),
 673                        REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 674                {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 675                        N_("do not show diffstat of what changed upstream"),
 676                        PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 677                OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
 678                         N_("passed to 'git apply'")),
 679                OPT_BOOL(0, "signoff", &options.signoff,
 680                         N_("add a Signed-off-by: line to each commit")),
 681                OPT_BOOL(0, "committer-date-is-author-date",
 682                         &committer_date_is_author_date,
 683                         N_("passed to 'git am'")),
 684                OPT_BOOL(0, "ignore-date", &ignore_date,
 685                         N_("passed to 'git am'")),
 686                OPT_BIT('f', "force-rebase", &options.flags,
 687                        N_("cherry-pick all commits, even if unchanged"),
 688                        REBASE_FORCE),
 689                OPT_BIT(0, "no-ff", &options.flags,
 690                        N_("cherry-pick all commits, even if unchanged"),
 691                        REBASE_FORCE),
 692                OPT_CMDMODE(0, "continue", &action, N_("continue"),
 693                            ACTION_CONTINUE),
 694                OPT_CMDMODE(0, "skip", &action,
 695                            N_("skip current patch and continue"), ACTION_SKIP),
 696                OPT_CMDMODE(0, "abort", &action,
 697                            N_("abort and check out the original branch"),
 698                            ACTION_ABORT),
 699                OPT_CMDMODE(0, "quit", &action,
 700                            N_("abort but keep HEAD where it is"), ACTION_QUIT),
 701                OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
 702                            "during an interactive rebase"), ACTION_EDIT_TODO),
 703                OPT_CMDMODE(0, "show-current-patch", &action,
 704                            N_("show the patch file being applied or merged"),
 705                            ACTION_SHOW_CURRENT_PATCH),
 706                { OPTION_CALLBACK, 'm', "merge", &options, NULL,
 707                        N_("use merging strategies to rebase"),
 708                        PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 709                        parse_opt_merge },
 710                { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
 711                        N_("let the user edit the list of commits to rebase"),
 712                        PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 713                        parse_opt_interactive },
 714                OPT_SET_INT('p', "preserve-merges", &options.type,
 715                            N_("try to recreate merges instead of ignoring "
 716                               "them"), REBASE_PRESERVE_MERGES),
 717                OPT_BOOL(0, "rerere-autoupdate",
 718                         &options.allow_rerere_autoupdate,
 719                         N_("allow rerere to update index  with resolved "
 720                            "conflict")),
 721                OPT_BOOL('k', "keep-empty", &options.keep_empty,
 722                         N_("preserve empty commits during rebase")),
 723                OPT_BOOL(0, "autosquash", &options.autosquash,
 724                         N_("move commits that begin with "
 725                            "squash!/fixup! under -i")),
 726                { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 727                        N_("GPG-sign commits"),
 728                        PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 729                OPT_STRING_LIST(0, "whitespace", &whitespace,
 730                                N_("whitespace"), N_("passed to 'git apply'")),
 731                OPT_SET_INT('C', NULL, &opt_c, N_("passed to 'git apply'"),
 732                            REBASE_AM),
 733                OPT_BOOL(0, "autostash", &options.autostash,
 734                         N_("automatically stash/stash pop before and after")),
 735                OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
 736                                N_("add exec lines after each commit of the "
 737                                   "editable list")),
 738                OPT_BOOL(0, "allow-empty-message",
 739                         &options.allow_empty_message,
 740                         N_("allow rebasing commits with empty messages")),
 741                {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
 742                        N_("mode"),
 743                        N_("try to rebase merges instead of skipping them"),
 744                        PARSE_OPT_OPTARG, NULL, (intptr_t)""},
 745                OPT_BOOL(0, "fork-point", &fork_point,
 746                         N_("use 'merge-base --fork-point' to refine upstream")),
 747                OPT_STRING('s', "strategy", &options.strategy,
 748                           N_("strategy"), N_("use the given merge strategy")),
 749                OPT_STRING_LIST('X', "strategy-option", &strategy_options,
 750                                N_("option"),
 751                                N_("pass the argument through to the merge "
 752                                   "strategy")),
 753                OPT_BOOL(0, "root", &options.root,
 754                         N_("rebase all reachable commits up to the root(s)")),
 755                OPT_END(),
 756        };
 757
 758        /*
 759         * NEEDSWORK: Once the builtin rebase has been tested enough
 760         * and git-legacy-rebase.sh is retired to contrib/, this preamble
 761         * can be removed.
 762         */
 763
 764        if (!use_builtin_rebase()) {
 765                const char *path = mkpath("%s/git-legacy-rebase",
 766                                          git_exec_path());
 767
 768                if (sane_execvp(path, (char **)argv) < 0)
 769                        die_errno(_("could not exec %s"), path);
 770                else
 771                        BUG("sane_execvp() returned???");
 772        }
 773
 774        if (argc == 2 && !strcmp(argv[1], "-h"))
 775                usage_with_options(builtin_rebase_usage,
 776                                   builtin_rebase_options);
 777
 778        prefix = setup_git_directory();
 779        trace_repo_setup(prefix);
 780        setup_work_tree();
 781
 782        git_config(rebase_config, &options);
 783
 784        strbuf_reset(&buf);
 785        strbuf_addf(&buf, "%s/applying", apply_dir());
 786        if(file_exists(buf.buf))
 787                die(_("It looks like 'git am' is in progress. Cannot rebase."));
 788
 789        if (is_directory(apply_dir())) {
 790                options.type = REBASE_AM;
 791                options.state_dir = apply_dir();
 792        } else if (is_directory(merge_dir())) {
 793                strbuf_reset(&buf);
 794                strbuf_addf(&buf, "%s/rewritten", merge_dir());
 795                if (is_directory(buf.buf)) {
 796                        options.type = REBASE_PRESERVE_MERGES;
 797                        options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 798                } else {
 799                        strbuf_reset(&buf);
 800                        strbuf_addf(&buf, "%s/interactive", merge_dir());
 801                        if(file_exists(buf.buf)) {
 802                                options.type = REBASE_INTERACTIVE;
 803                                options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 804                        } else
 805                                options.type = REBASE_MERGE;
 806                }
 807                options.state_dir = merge_dir();
 808        }
 809
 810        if (options.type != REBASE_UNSPECIFIED)
 811                in_progress = 1;
 812
 813        total_argc = argc;
 814        argc = parse_options(argc, argv, prefix,
 815                             builtin_rebase_options,
 816                             builtin_rebase_usage, 0);
 817
 818        if (action != NO_ACTION && total_argc != 2) {
 819                usage_with_options(builtin_rebase_usage,
 820                                   builtin_rebase_options);
 821        }
 822
 823        if (argc > 2)
 824                usage_with_options(builtin_rebase_usage,
 825                                   builtin_rebase_options);
 826
 827        if (action != NO_ACTION && !in_progress)
 828                die(_("No rebase in progress?"));
 829
 830        if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 831                die(_("The --edit-todo action can only be used during "
 832                      "interactive rebase."));
 833
 834        switch (action) {
 835        case ACTION_CONTINUE: {
 836                struct object_id head;
 837                struct lock_file lock_file = LOCK_INIT;
 838                int fd;
 839
 840                options.action = "continue";
 841
 842                /* Sanity check */
 843                if (get_oid("HEAD", &head))
 844                        die(_("Cannot read HEAD"));
 845
 846                fd = hold_locked_index(&lock_file, 0);
 847                if (read_index(the_repository->index) < 0)
 848                        die(_("could not read index"));
 849                refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 850                              NULL);
 851                if (0 <= fd)
 852                        update_index_if_able(the_repository->index,
 853                                             &lock_file);
 854                rollback_lock_file(&lock_file);
 855
 856                if (has_unstaged_changes(1)) {
 857                        puts(_("You must edit all merge conflicts and then\n"
 858                               "mark them as resolved using git add"));
 859                        exit(1);
 860                }
 861                if (read_basic_state(&options))
 862                        exit(1);
 863                goto run_rebase;
 864        }
 865        case ACTION_SKIP: {
 866                struct string_list merge_rr = STRING_LIST_INIT_DUP;
 867
 868                options.action = "skip";
 869
 870                rerere_clear(&merge_rr);
 871                string_list_clear(&merge_rr, 1);
 872
 873                if (reset_head(NULL, "reset", NULL, 0) < 0)
 874                        die(_("could not discard worktree changes"));
 875                if (read_basic_state(&options))
 876                        exit(1);
 877                goto run_rebase;
 878        }
 879        case ACTION_ABORT: {
 880                struct string_list merge_rr = STRING_LIST_INIT_DUP;
 881                options.action = "abort";
 882
 883                rerere_clear(&merge_rr);
 884                string_list_clear(&merge_rr, 1);
 885
 886                if (read_basic_state(&options))
 887                        exit(1);
 888                if (reset_head(&options.orig_head, "reset",
 889                               options.head_name, 0) < 0)
 890                        die(_("could not move back to %s"),
 891                            oid_to_hex(&options.orig_head));
 892                ret = finish_rebase(&options);
 893                goto cleanup;
 894        }
 895        case ACTION_QUIT: {
 896                strbuf_reset(&buf);
 897                strbuf_addstr(&buf, options.state_dir);
 898                ret = !!remove_dir_recursively(&buf, 0);
 899                if (ret)
 900                        die(_("could not remove '%s'"), options.state_dir);
 901                goto cleanup;
 902        }
 903        case ACTION_EDIT_TODO:
 904                options.action = "edit-todo";
 905                options.dont_finish_rebase = 1;
 906                goto run_rebase;
 907        case ACTION_SHOW_CURRENT_PATCH:
 908                options.action = "show-current-patch";
 909                options.dont_finish_rebase = 1;
 910                goto run_rebase;
 911        case NO_ACTION:
 912                break;
 913        default:
 914                BUG("action: %d", action);
 915        }
 916
 917        /* Make sure no rebase is in progress */
 918        if (in_progress) {
 919                const char *last_slash = strrchr(options.state_dir, '/');
 920                const char *state_dir_base =
 921                        last_slash ? last_slash + 1 : options.state_dir;
 922                const char *cmd_live_rebase =
 923                        "git rebase (--continue | --abort | --skip)";
 924                strbuf_reset(&buf);
 925                strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
 926                die(_("It seems that there is already a %s directory, and\n"
 927                      "I wonder if you are in the middle of another rebase.  "
 928                      "If that is the\n"
 929                      "case, please try\n\t%s\n"
 930                      "If that is not the case, please\n\t%s\n"
 931                      "and run me again.  I am stopping in case you still "
 932                      "have something\n"
 933                      "valuable there.\n"),
 934                    state_dir_base, cmd_live_rebase, buf.buf);
 935        }
 936
 937        if (!(options.flags & REBASE_NO_QUIET))
 938                strbuf_addstr(&options.git_am_opt, " -q");
 939
 940        if (committer_date_is_author_date) {
 941                strbuf_addstr(&options.git_am_opt,
 942                              " --committer-date-is-author-date");
 943                options.flags |= REBASE_FORCE;
 944        }
 945
 946        if (ignore_whitespace)
 947                strbuf_addstr(&options.git_am_opt, " --ignore-whitespace");
 948
 949        if (ignore_date) {
 950                strbuf_addstr(&options.git_am_opt, " --ignore-date");
 951                options.flags |= REBASE_FORCE;
 952        }
 953
 954        if (options.keep_empty)
 955                imply_interactive(&options, "--keep-empty");
 956
 957        if (gpg_sign) {
 958                free(options.gpg_sign_opt);
 959                options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
 960        }
 961
 962        if (opt_c >= 0)
 963                strbuf_addf(&options.git_am_opt, " -C%d", opt_c);
 964
 965        if (whitespace.nr) {
 966                int i;
 967
 968                for (i = 0; i < whitespace.nr; i++) {
 969                        const char *item = whitespace.items[i].string;
 970
 971                        strbuf_addf(&options.git_am_opt, " --whitespace=%s",
 972                                    item);
 973
 974                        if ((!strcmp(item, "fix")) || (!strcmp(item, "strip")))
 975                                options.flags |= REBASE_FORCE;
 976                }
 977        }
 978
 979        if (exec.nr) {
 980                int i;
 981
 982                imply_interactive(&options, "--exec");
 983
 984                strbuf_reset(&buf);
 985                for (i = 0; i < exec.nr; i++)
 986                        strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
 987                options.cmd = xstrdup(buf.buf);
 988        }
 989
 990        if (rebase_merges) {
 991                if (!*rebase_merges)
 992                        ; /* default mode; do nothing */
 993                else if (!strcmp("rebase-cousins", rebase_merges))
 994                        options.rebase_cousins = 1;
 995                else if (strcmp("no-rebase-cousins", rebase_merges))
 996                        die(_("Unknown mode: %s"), rebase_merges);
 997                options.rebase_merges = 1;
 998                imply_interactive(&options, "--rebase-merges");
 999        }
1000
1001        if (strategy_options.nr) {
1002                int i;
1003
1004                if (!options.strategy)
1005                        options.strategy = "recursive";
1006
1007                strbuf_reset(&buf);
1008                for (i = 0; i < strategy_options.nr; i++)
1009                        strbuf_addf(&buf, " --%s",
1010                                    strategy_options.items[i].string);
1011                options.strategy_opts = xstrdup(buf.buf);
1012        }
1013
1014        if (options.strategy) {
1015                options.strategy = xstrdup(options.strategy);
1016                switch (options.type) {
1017                case REBASE_AM:
1018                        die(_("--strategy requires --merge or --interactive"));
1019                case REBASE_MERGE:
1020                case REBASE_INTERACTIVE:
1021                case REBASE_PRESERVE_MERGES:
1022                        /* compatible */
1023                        break;
1024                case REBASE_UNSPECIFIED:
1025                        options.type = REBASE_MERGE;
1026                        break;
1027                default:
1028                        BUG("unhandled rebase type (%d)", options.type);
1029                }
1030        }
1031
1032        if (options.root && !options.onto_name)
1033                imply_interactive(&options, "--root without --onto");
1034
1035        switch (options.type) {
1036        case REBASE_MERGE:
1037        case REBASE_INTERACTIVE:
1038        case REBASE_PRESERVE_MERGES:
1039                options.state_dir = merge_dir();
1040                break;
1041        case REBASE_AM:
1042                options.state_dir = apply_dir();
1043                break;
1044        default:
1045                /* the default rebase backend is `--am` */
1046                options.type = REBASE_AM;
1047                options.state_dir = apply_dir();
1048                break;
1049        }
1050
1051        if (options.signoff) {
1052                if (options.type == REBASE_PRESERVE_MERGES)
1053                        die("cannot combine '--signoff' with "
1054                            "'--preserve-merges'");
1055                strbuf_addstr(&options.git_am_opt, " --signoff");
1056                options.flags |= REBASE_FORCE;
1057        }
1058
1059        if (!options.root) {
1060                if (argc < 1)
1061                        die("TODO: handle @{upstream}");
1062                else {
1063                        options.upstream_name = argv[0];
1064                        argc--;
1065                        argv++;
1066                        if (!strcmp(options.upstream_name, "-"))
1067                                options.upstream_name = "@{-1}";
1068                }
1069                options.upstream = peel_committish(options.upstream_name);
1070                if (!options.upstream)
1071                        die(_("invalid upstream '%s'"), options.upstream_name);
1072                options.upstream_arg = options.upstream_name;
1073        } else {
1074                if (!options.onto_name) {
1075                        if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1076                                        &squash_onto, NULL, NULL) < 0)
1077                                die(_("Could not create new root commit"));
1078                        options.squash_onto = &squash_onto;
1079                        options.onto_name = squash_onto_name =
1080                                xstrdup(oid_to_hex(&squash_onto));
1081                }
1082                options.upstream_name = NULL;
1083                options.upstream = NULL;
1084                if (argc > 1)
1085                        usage_with_options(builtin_rebase_usage,
1086                                           builtin_rebase_options);
1087                options.upstream_arg = "--root";
1088        }
1089
1090        /* Make sure the branch to rebase onto is valid. */
1091        if (!options.onto_name)
1092                options.onto_name = options.upstream_name;
1093        if (strstr(options.onto_name, "...")) {
1094                if (get_oid_mb(options.onto_name, &merge_base) < 0)
1095                        die(_("'%s': need exactly one merge base"),
1096                            options.onto_name);
1097                options.onto = lookup_commit_or_die(&merge_base,
1098                                                    options.onto_name);
1099        } else {
1100                options.onto = peel_committish(options.onto_name);
1101                if (!options.onto)
1102                        die(_("Does not point to a valid commit '%s'"),
1103                                options.onto_name);
1104        }
1105
1106        /*
1107         * If the branch to rebase is given, that is the branch we will rebase
1108         * branch_name -- branch/commit being rebased, or
1109         *                HEAD (already detached)
1110         * orig_head -- commit object name of tip of the branch before rebasing
1111         * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1112         */
1113        if (argc == 1) {
1114                /* Is it "rebase other branchname" or "rebase other commit"? */
1115                branch_name = argv[0];
1116                options.switch_to = argv[0];
1117
1118                /* Is it a local branch? */
1119                strbuf_reset(&buf);
1120                strbuf_addf(&buf, "refs/heads/%s", branch_name);
1121                if (!read_ref(buf.buf, &options.orig_head))
1122                        options.head_name = xstrdup(buf.buf);
1123                /* If not is it a valid ref (branch or commit)? */
1124                else if (!get_oid(branch_name, &options.orig_head))
1125                        options.head_name = NULL;
1126                else
1127                        die(_("fatal: no such branch/commit '%s'"),
1128                            branch_name);
1129        } else if (argc == 0) {
1130                /* Do not need to switch branches, we are already on it. */
1131                options.head_name =
1132                        xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1133                                         &flags));
1134                if (!options.head_name)
1135                        die(_("No such ref: %s"), "HEAD");
1136                if (flags & REF_ISSYMREF) {
1137                        if (!skip_prefix(options.head_name,
1138                                         "refs/heads/", &branch_name))
1139                                branch_name = options.head_name;
1140
1141                } else {
1142                        free(options.head_name);
1143                        options.head_name = NULL;
1144                        branch_name = "HEAD";
1145                }
1146                if (get_oid("HEAD", &options.orig_head))
1147                        die(_("Could not resolve HEAD to a revision"));
1148        } else
1149                BUG("unexpected number of arguments left to parse");
1150
1151        if (fork_point > 0) {
1152                struct commit *head =
1153                        lookup_commit_reference(the_repository,
1154                                                &options.orig_head);
1155                options.restrict_revision =
1156                        get_fork_point(options.upstream_name, head);
1157        }
1158
1159        if (read_index(the_repository->index) < 0)
1160                die(_("could not read index"));
1161
1162        if (options.autostash) {
1163                struct lock_file lock_file = LOCK_INIT;
1164                int fd;
1165
1166                fd = hold_locked_index(&lock_file, 0);
1167                refresh_cache(REFRESH_QUIET);
1168                if (0 <= fd)
1169                        update_index_if_able(&the_index, &lock_file);
1170                rollback_lock_file(&lock_file);
1171
1172                if (has_unstaged_changes(0) || has_uncommitted_changes(0)) {
1173                        const char *autostash =
1174                                state_dir_path("autostash", &options);
1175                        struct child_process stash = CHILD_PROCESS_INIT;
1176                        struct object_id oid;
1177                        struct commit *head =
1178                                lookup_commit_reference(the_repository,
1179                                                        &options.orig_head);
1180
1181                        argv_array_pushl(&stash.args,
1182                                         "stash", "create", "autostash", NULL);
1183                        stash.git_cmd = 1;
1184                        stash.no_stdin = 1;
1185                        strbuf_reset(&buf);
1186                        if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
1187                                die(_("Cannot autostash"));
1188                        strbuf_trim_trailing_newline(&buf);
1189                        if (get_oid(buf.buf, &oid))
1190                                die(_("Unexpected stash response: '%s'"),
1191                                    buf.buf);
1192                        strbuf_reset(&buf);
1193                        strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
1194
1195                        if (safe_create_leading_directories_const(autostash))
1196                                die(_("Could not create directory for '%s'"),
1197                                    options.state_dir);
1198                        write_file(autostash, "%s", buf.buf);
1199                        printf(_("Created autostash: %s\n"), buf.buf);
1200                        if (reset_head(&head->object.oid, "reset --hard",
1201                                       NULL, 0) < 0)
1202                                die(_("could not reset --hard"));
1203                        printf(_("HEAD is now at %s"),
1204                               find_unique_abbrev(&head->object.oid,
1205                                                  DEFAULT_ABBREV));
1206                        strbuf_reset(&buf);
1207                        pp_commit_easy(CMIT_FMT_ONELINE, head, &buf);
1208                        if (buf.len > 0)
1209                                printf(" %s", buf.buf);
1210                        putchar('\n');
1211
1212                        if (discard_index(the_repository->index) < 0 ||
1213                                read_index(the_repository->index) < 0)
1214                                die(_("could not read index"));
1215                }
1216        }
1217
1218        if (require_clean_work_tree("rebase",
1219                                    _("Please commit or stash them."), 1, 1)) {
1220                ret = 1;
1221                goto cleanup;
1222        }
1223
1224        /*
1225         * Now we are rebasing commits upstream..orig_head (or with --root,
1226         * everything leading up to orig_head) on top of onto.
1227         */
1228
1229        /*
1230         * Check if we are already based on onto with linear history,
1231         * but this should be done only when upstream and onto are the same
1232         * and if this is not an interactive rebase.
1233         */
1234        if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
1235            !is_interactive(&options) && !options.restrict_revision &&
1236            options.upstream &&
1237            !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
1238                int flag;
1239
1240                if (!(options.flags & REBASE_FORCE)) {
1241                        /* Lazily switch to the target branch if needed... */
1242                        if (options.switch_to) {
1243                                struct object_id oid;
1244
1245                                if (get_oid(options.switch_to, &oid) < 0) {
1246                                        ret = !!error(_("could not parse '%s'"),
1247                                                      options.switch_to);
1248                                        goto cleanup;
1249                                }
1250
1251                                strbuf_reset(&buf);
1252                                strbuf_addf(&buf, "rebase: checkout %s",
1253                                            options.switch_to);
1254                                if (reset_head(&oid, "checkout",
1255                                               options.head_name, 0) < 0) {
1256                                        ret = !!error(_("could not switch to "
1257                                                        "%s"),
1258                                                      options.switch_to);
1259                                        goto cleanup;
1260                                }
1261                        }
1262
1263                        if (!(options.flags & REBASE_NO_QUIET))
1264                                ; /* be quiet */
1265                        else if (!strcmp(branch_name, "HEAD") &&
1266                                 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1267                                puts(_("HEAD is up to date."));
1268                        else
1269                                printf(_("Current branch %s is up to date.\n"),
1270                                       branch_name);
1271                        ret = !!finish_rebase(&options);
1272                        goto cleanup;
1273                } else if (!(options.flags & REBASE_NO_QUIET))
1274                        ; /* be quiet */
1275                else if (!strcmp(branch_name, "HEAD") &&
1276                         resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1277                        puts(_("HEAD is up to date, rebase forced."));
1278                else
1279                        printf(_("Current branch %s is up to date, rebase "
1280                                 "forced.\n"), branch_name);
1281        }
1282
1283        /* If a hook exists, give it a chance to interrupt*/
1284        if (!ok_to_skip_pre_rebase &&
1285            run_hook_le(NULL, "pre-rebase", options.upstream_arg,
1286                        argc ? argv[0] : NULL, NULL))
1287                die(_("The pre-rebase hook refused to rebase."));
1288
1289        if (options.flags & REBASE_DIFFSTAT) {
1290                struct diff_options opts;
1291
1292                if (options.flags & REBASE_VERBOSE)
1293                        printf(_("Changes from %s to %s:\n"),
1294                                oid_to_hex(&merge_base),
1295                                oid_to_hex(&options.onto->object.oid));
1296
1297                /* We want color (if set), but no pager */
1298                diff_setup(&opts);
1299                opts.stat_width = -1; /* use full terminal width */
1300                opts.stat_graph_width = -1; /* respect statGraphWidth config */
1301                opts.output_format |=
1302                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
1303                opts.detect_rename = DIFF_DETECT_RENAME;
1304                diff_setup_done(&opts);
1305                diff_tree_oid(&merge_base, &options.onto->object.oid,
1306                              "", &opts);
1307                diffcore_std(&opts);
1308                diff_flush(&opts);
1309        }
1310
1311        if (is_interactive(&options))
1312                goto run_rebase;
1313
1314        /* Detach HEAD and reset the tree */
1315        if (options.flags & REBASE_NO_QUIET)
1316                printf(_("First, rewinding head to replay your work on top of "
1317                         "it...\n"));
1318
1319        strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
1320        if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
1321                die(_("Could not detach HEAD"));
1322        strbuf_release(&msg);
1323
1324        strbuf_addf(&revisions, "%s..%s",
1325                    options.root ? oid_to_hex(&options.onto->object.oid) :
1326                    (options.restrict_revision ?
1327                     oid_to_hex(&options.restrict_revision->object.oid) :
1328                     oid_to_hex(&options.upstream->object.oid)),
1329                    oid_to_hex(&options.orig_head));
1330
1331        options.revisions = revisions.buf;
1332
1333run_rebase:
1334        ret = !!run_specific_rebase(&options);
1335
1336cleanup:
1337        strbuf_release(&revisions);
1338        free(options.head_name);
1339        free(options.gpg_sign_opt);
1340        free(options.cmd);
1341        free(squash_onto_name);
1342        return ret;
1343}