bc92c9b5299de3d72378f67371e0d42990385ea7
   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 1;
  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        struct strbuf git_format_patch_opt;
 102};
 103
 104static int is_interactive(struct rebase_options *opts)
 105{
 106        return opts->type == REBASE_INTERACTIVE ||
 107                opts->type == REBASE_PRESERVE_MERGES;
 108}
 109
 110static void imply_interactive(struct rebase_options *opts, const char *option)
 111{
 112        switch (opts->type) {
 113        case REBASE_AM:
 114                die(_("%s requires an interactive rebase"), option);
 115                break;
 116        case REBASE_INTERACTIVE:
 117        case REBASE_PRESERVE_MERGES:
 118                break;
 119        case REBASE_MERGE:
 120                /* we silently *upgrade* --merge to --interactive if needed */
 121        default:
 122                opts->type = REBASE_INTERACTIVE; /* implied */
 123                break;
 124        }
 125}
 126
 127/* Returns the filename prefixed by the state_dir */
 128static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 129{
 130        static struct strbuf path = STRBUF_INIT;
 131        static size_t prefix_len;
 132
 133        if (!prefix_len) {
 134                strbuf_addf(&path, "%s/", opts->state_dir);
 135                prefix_len = path.len;
 136        }
 137
 138        strbuf_setlen(&path, prefix_len);
 139        strbuf_addstr(&path, filename);
 140        return path.buf;
 141}
 142
 143/* Read one file, then strip line endings */
 144static int read_one(const char *path, struct strbuf *buf)
 145{
 146        if (strbuf_read_file(buf, path, 0) < 0)
 147                return error_errno(_("could not read '%s'"), path);
 148        strbuf_trim_trailing_newline(buf);
 149        return 0;
 150}
 151
 152/* Initialize the rebase options from the state directory. */
 153static int read_basic_state(struct rebase_options *opts)
 154{
 155        struct strbuf head_name = STRBUF_INIT;
 156        struct strbuf buf = STRBUF_INIT;
 157        struct object_id oid;
 158
 159        if (read_one(state_dir_path("head-name", opts), &head_name) ||
 160            read_one(state_dir_path("onto", opts), &buf))
 161                return -1;
 162        opts->head_name = starts_with(head_name.buf, "refs/") ?
 163                xstrdup(head_name.buf) : NULL;
 164        strbuf_release(&head_name);
 165        if (get_oid(buf.buf, &oid))
 166                return error(_("could not get 'onto': '%s'"), buf.buf);
 167        opts->onto = lookup_commit_or_die(&oid, buf.buf);
 168
 169        /*
 170         * We always write to orig-head, but interactive rebase used to write to
 171         * head. Fall back to reading from head to cover for the case that the
 172         * user upgraded git with an ongoing interactive rebase.
 173         */
 174        strbuf_reset(&buf);
 175        if (file_exists(state_dir_path("orig-head", opts))) {
 176                if (read_one(state_dir_path("orig-head", opts), &buf))
 177                        return -1;
 178        } else if (read_one(state_dir_path("head", opts), &buf))
 179                return -1;
 180        if (get_oid(buf.buf, &opts->orig_head))
 181                return error(_("invalid orig-head: '%s'"), buf.buf);
 182
 183        strbuf_reset(&buf);
 184        if (read_one(state_dir_path("quiet", opts), &buf))
 185                return -1;
 186        if (buf.len)
 187                opts->flags &= ~REBASE_NO_QUIET;
 188        else
 189                opts->flags |= REBASE_NO_QUIET;
 190
 191        if (file_exists(state_dir_path("verbose", opts)))
 192                opts->flags |= REBASE_VERBOSE;
 193
 194        if (file_exists(state_dir_path("signoff", opts))) {
 195                opts->signoff = 1;
 196                opts->flags |= REBASE_FORCE;
 197        }
 198
 199        if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 200                strbuf_reset(&buf);
 201                if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
 202                            &buf))
 203                        return -1;
 204                if (!strcmp(buf.buf, "--rerere-autoupdate"))
 205                        opts->allow_rerere_autoupdate = 1;
 206                else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 207                        opts->allow_rerere_autoupdate = 0;
 208                else
 209                        warning(_("ignoring invalid allow_rerere_autoupdate: "
 210                                  "'%s'"), buf.buf);
 211        } else
 212                opts->allow_rerere_autoupdate = -1;
 213
 214        if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 215                strbuf_reset(&buf);
 216                if (read_one(state_dir_path("gpg_sign_opt", opts),
 217                            &buf))
 218                        return -1;
 219                free(opts->gpg_sign_opt);
 220                opts->gpg_sign_opt = xstrdup(buf.buf);
 221        }
 222
 223        if (file_exists(state_dir_path("strategy", opts))) {
 224                strbuf_reset(&buf);
 225                if (read_one(state_dir_path("strategy", opts), &buf))
 226                        return -1;
 227                free(opts->strategy);
 228                opts->strategy = xstrdup(buf.buf);
 229        }
 230
 231        if (file_exists(state_dir_path("strategy_opts", opts))) {
 232                strbuf_reset(&buf);
 233                if (read_one(state_dir_path("strategy_opts", opts), &buf))
 234                        return -1;
 235                free(opts->strategy_opts);
 236                opts->strategy_opts = xstrdup(buf.buf);
 237        }
 238
 239        strbuf_release(&buf);
 240
 241        return 0;
 242}
 243
 244static int apply_autostash(struct rebase_options *opts)
 245{
 246        const char *path = state_dir_path("autostash", opts);
 247        struct strbuf autostash = STRBUF_INIT;
 248        struct child_process stash_apply = CHILD_PROCESS_INIT;
 249
 250        if (!file_exists(path))
 251                return 0;
 252
 253        if (read_one(path, &autostash))
 254                return error(_("Could not read '%s'"), path);
 255        /* Ensure that the hash is not mistaken for a number */
 256        strbuf_addstr(&autostash, "^0");
 257        argv_array_pushl(&stash_apply.args,
 258                         "stash", "apply", autostash.buf, NULL);
 259        stash_apply.git_cmd = 1;
 260        stash_apply.no_stderr = stash_apply.no_stdout =
 261                stash_apply.no_stdin = 1;
 262        if (!run_command(&stash_apply))
 263                printf(_("Applied autostash.\n"));
 264        else {
 265                struct argv_array args = ARGV_ARRAY_INIT;
 266                int res = 0;
 267
 268                argv_array_pushl(&args,
 269                                 "stash", "store", "-m", "autostash", "-q",
 270                                 autostash.buf, NULL);
 271                if (run_command_v_opt(args.argv, RUN_GIT_CMD))
 272                        res = error(_("Cannot store %s"), autostash.buf);
 273                argv_array_clear(&args);
 274                strbuf_release(&autostash);
 275                if (res)
 276                        return res;
 277
 278                fprintf(stderr,
 279                        _("Applying autostash resulted in conflicts.\n"
 280                          "Your changes are safe in the stash.\n"
 281                          "You can run \"git stash pop\" or \"git stash drop\" "
 282                          "at any time.\n"));
 283        }
 284
 285        strbuf_release(&autostash);
 286        return 0;
 287}
 288
 289static int finish_rebase(struct rebase_options *opts)
 290{
 291        struct strbuf dir = STRBUF_INIT;
 292        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 293
 294        delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 295        apply_autostash(opts);
 296        close_all_packs(the_repository->objects);
 297        /*
 298         * We ignore errors in 'gc --auto', since the
 299         * user should see them.
 300         */
 301        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 302        strbuf_addstr(&dir, opts->state_dir);
 303        remove_dir_recursively(&dir, 0);
 304        strbuf_release(&dir);
 305
 306        return 0;
 307}
 308
 309static struct commit *peel_committish(const char *name)
 310{
 311        struct object *obj;
 312        struct object_id oid;
 313
 314        if (get_oid(name, &oid))
 315                return NULL;
 316        obj = parse_object(the_repository, &oid);
 317        return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 318}
 319
 320static void add_var(struct strbuf *buf, const char *name, const char *value)
 321{
 322        if (!value)
 323                strbuf_addf(buf, "unset %s; ", name);
 324        else {
 325                strbuf_addf(buf, "%s=", name);
 326                sq_quote_buf(buf, value);
 327                strbuf_addstr(buf, "; ");
 328        }
 329}
 330
 331static const char *resolvemsg =
 332N_("Resolve all conflicts manually, mark them as resolved with\n"
 333"\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 334"You can instead skip this commit: run \"git rebase --skip\".\n"
 335"To abort and get back to the state before \"git rebase\", run "
 336"\"git rebase --abort\".");
 337
 338static int run_specific_rebase(struct rebase_options *opts)
 339{
 340        const char *argv[] = { NULL, NULL };
 341        struct strbuf script_snippet = STRBUF_INIT;
 342        int status;
 343        const char *backend, *backend_func;
 344
 345        if (opts->type == REBASE_INTERACTIVE) {
 346                /* Run builtin interactive rebase */
 347                struct child_process child = CHILD_PROCESS_INIT;
 348
 349                argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
 350                                 resolvemsg);
 351                if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 352                        argv_array_push(&child.env_array, "GIT_EDITOR=:");
 353                        opts->autosquash = 0;
 354                }
 355
 356                child.git_cmd = 1;
 357                argv_array_push(&child.args, "rebase--interactive");
 358
 359                if (opts->action)
 360                        argv_array_pushf(&child.args, "--%s", opts->action);
 361                if (opts->keep_empty)
 362                        argv_array_push(&child.args, "--keep-empty");
 363                if (opts->rebase_merges)
 364                        argv_array_push(&child.args, "--rebase-merges");
 365                if (opts->rebase_cousins)
 366                        argv_array_push(&child.args, "--rebase-cousins");
 367                if (opts->autosquash)
 368                        argv_array_push(&child.args, "--autosquash");
 369                if (opts->flags & REBASE_VERBOSE)
 370                        argv_array_push(&child.args, "--verbose");
 371                if (opts->flags & REBASE_FORCE)
 372                        argv_array_push(&child.args, "--no-ff");
 373                if (opts->restrict_revision)
 374                        argv_array_pushf(&child.args,
 375                                         "--restrict-revision=^%s",
 376                                         oid_to_hex(&opts->restrict_revision->object.oid));
 377                if (opts->upstream)
 378                        argv_array_pushf(&child.args, "--upstream=%s",
 379                                         oid_to_hex(&opts->upstream->object.oid));
 380                if (opts->onto)
 381                        argv_array_pushf(&child.args, "--onto=%s",
 382                                         oid_to_hex(&opts->onto->object.oid));
 383                if (opts->squash_onto)
 384                        argv_array_pushf(&child.args, "--squash-onto=%s",
 385                                         oid_to_hex(opts->squash_onto));
 386                if (opts->onto_name)
 387                        argv_array_pushf(&child.args, "--onto-name=%s",
 388                                         opts->onto_name);
 389                argv_array_pushf(&child.args, "--head-name=%s",
 390                                 opts->head_name ?
 391                                 opts->head_name : "detached HEAD");
 392                if (opts->strategy)
 393                        argv_array_pushf(&child.args, "--strategy=%s",
 394                                         opts->strategy);
 395                if (opts->strategy_opts)
 396                        argv_array_pushf(&child.args, "--strategy-opts=%s",
 397                                         opts->strategy_opts);
 398                if (opts->switch_to)
 399                        argv_array_pushf(&child.args, "--switch-to=%s",
 400                                         opts->switch_to);
 401                if (opts->cmd)
 402                        argv_array_pushf(&child.args, "--cmd=%s", opts->cmd);
 403                if (opts->allow_empty_message)
 404                        argv_array_push(&child.args, "--allow-empty-message");
 405                if (opts->allow_rerere_autoupdate > 0)
 406                        argv_array_push(&child.args, "--rerere-autoupdate");
 407                else if (opts->allow_rerere_autoupdate == 0)
 408                        argv_array_push(&child.args, "--no-rerere-autoupdate");
 409                if (opts->gpg_sign_opt)
 410                        argv_array_push(&child.args, opts->gpg_sign_opt);
 411                if (opts->signoff)
 412                        argv_array_push(&child.args, "--signoff");
 413
 414                status = run_command(&child);
 415                goto finished_rebase;
 416        }
 417
 418        add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 419        add_var(&script_snippet, "state_dir", opts->state_dir);
 420
 421        add_var(&script_snippet, "upstream_name", opts->upstream_name);
 422        add_var(&script_snippet, "upstream", opts->upstream ?
 423                oid_to_hex(&opts->upstream->object.oid) : NULL);
 424        add_var(&script_snippet, "head_name",
 425                opts->head_name ? opts->head_name : "detached HEAD");
 426        add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 427        add_var(&script_snippet, "onto", opts->onto ?
 428                oid_to_hex(&opts->onto->object.oid) : NULL);
 429        add_var(&script_snippet, "onto_name", opts->onto_name);
 430        add_var(&script_snippet, "revisions", opts->revisions);
 431        add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 432                oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 433        add_var(&script_snippet, "GIT_QUIET",
 434                opts->flags & REBASE_NO_QUIET ? "" : "t");
 435        add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 436        add_var(&script_snippet, "verbose",
 437                opts->flags & REBASE_VERBOSE ? "t" : "");
 438        add_var(&script_snippet, "diffstat",
 439                opts->flags & REBASE_DIFFSTAT ? "t" : "");
 440        add_var(&script_snippet, "force_rebase",
 441                opts->flags & REBASE_FORCE ? "t" : "");
 442        if (opts->switch_to)
 443                add_var(&script_snippet, "switch_to", opts->switch_to);
 444        add_var(&script_snippet, "action", opts->action ? opts->action : "");
 445        add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 446        add_var(&script_snippet, "allow_rerere_autoupdate",
 447                opts->allow_rerere_autoupdate < 0 ? "" :
 448                opts->allow_rerere_autoupdate ?
 449                "--rerere-autoupdate" : "--no-rerere-autoupdate");
 450        add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 451        add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 452        add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 453        add_var(&script_snippet, "cmd", opts->cmd);
 454        add_var(&script_snippet, "allow_empty_message",
 455                opts->allow_empty_message ?  "--allow-empty-message" : "");
 456        add_var(&script_snippet, "rebase_merges",
 457                opts->rebase_merges ? "t" : "");
 458        add_var(&script_snippet, "rebase_cousins",
 459                opts->rebase_cousins ? "t" : "");
 460        add_var(&script_snippet, "strategy", opts->strategy);
 461        add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
 462        add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
 463        add_var(&script_snippet, "squash_onto",
 464                opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
 465        add_var(&script_snippet, "git_format_patch_opt",
 466                opts->git_format_patch_opt.buf);
 467
 468        if (is_interactive(opts) &&
 469            !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 470                strbuf_addstr(&script_snippet,
 471                              "GIT_EDITOR=:; export GIT_EDITOR; ");
 472                opts->autosquash = 0;
 473        }
 474
 475        switch (opts->type) {
 476        case REBASE_AM:
 477                backend = "git-rebase--am";
 478                backend_func = "git_rebase__am";
 479                break;
 480        case REBASE_MERGE:
 481                backend = "git-rebase--merge";
 482                backend_func = "git_rebase__merge";
 483                break;
 484        case REBASE_PRESERVE_MERGES:
 485                backend = "git-rebase--preserve-merges";
 486                backend_func = "git_rebase__preserve_merges";
 487                break;
 488        default:
 489                BUG("Unhandled rebase type %d", opts->type);
 490                break;
 491        }
 492
 493        strbuf_addf(&script_snippet,
 494                    ". git-sh-setup && . git-rebase--common &&"
 495                    " . %s && %s", backend, backend_func);
 496        argv[0] = script_snippet.buf;
 497
 498        status = run_command_v_opt(argv, RUN_USING_SHELL);
 499finished_rebase:
 500        if (opts->dont_finish_rebase)
 501                ; /* do nothing */
 502        else if (opts->type == REBASE_INTERACTIVE)
 503                ; /* interactive rebase cleans up after itself */
 504        else if (status == 0) {
 505                if (!file_exists(state_dir_path("stopped-sha", opts)))
 506                        finish_rebase(opts);
 507        } else if (status == 2) {
 508                struct strbuf dir = STRBUF_INIT;
 509
 510                apply_autostash(opts);
 511                strbuf_addstr(&dir, opts->state_dir);
 512                remove_dir_recursively(&dir, 0);
 513                strbuf_release(&dir);
 514                die("Nothing to do");
 515        }
 516
 517        strbuf_release(&script_snippet);
 518
 519        return status ? -1 : 0;
 520}
 521
 522#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 523
 524static int reset_head(struct object_id *oid, const char *action,
 525                      const char *switch_to_branch, int detach_head,
 526                      const char *reflog_orig_head, const char *reflog_head)
 527{
 528        struct object_id head_oid;
 529        struct tree_desc desc;
 530        struct lock_file lock = LOCK_INIT;
 531        struct unpack_trees_options unpack_tree_opts;
 532        struct tree *tree;
 533        const char *reflog_action;
 534        struct strbuf msg = STRBUF_INIT;
 535        size_t prefix_len;
 536        struct object_id *orig = NULL, oid_orig,
 537                *old_orig = NULL, oid_old_orig;
 538        int ret = 0;
 539
 540        if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 541                BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 542
 543        if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 544                return -1;
 545
 546        if (!oid) {
 547                if (get_oid("HEAD", &head_oid)) {
 548                        rollback_lock_file(&lock);
 549                        return error(_("could not determine HEAD revision"));
 550                }
 551                oid = &head_oid;
 552        }
 553
 554        memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 555        setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 556        unpack_tree_opts.head_idx = 1;
 557        unpack_tree_opts.src_index = the_repository->index;
 558        unpack_tree_opts.dst_index = the_repository->index;
 559        unpack_tree_opts.fn = oneway_merge;
 560        unpack_tree_opts.update = 1;
 561        unpack_tree_opts.merge = 1;
 562        if (!detach_head)
 563                unpack_tree_opts.reset = 1;
 564
 565        if (read_index_unmerged(the_repository->index) < 0) {
 566                rollback_lock_file(&lock);
 567                return error(_("could not read index"));
 568        }
 569
 570        if (!fill_tree_descriptor(&desc, oid)) {
 571                error(_("failed to find tree of %s"), oid_to_hex(oid));
 572                rollback_lock_file(&lock);
 573                free((void *)desc.buffer);
 574                return -1;
 575        }
 576
 577        if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 578                rollback_lock_file(&lock);
 579                free((void *)desc.buffer);
 580                return -1;
 581        }
 582
 583        tree = parse_tree_indirect(oid);
 584        prime_cache_tree(the_repository->index, tree);
 585
 586        if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 587                ret = error(_("could not write index"));
 588        free((void *)desc.buffer);
 589
 590        if (ret)
 591                return ret;
 592
 593        reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 594        strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 595        prefix_len = msg.len;
 596
 597        if (!get_oid("ORIG_HEAD", &oid_old_orig))
 598                old_orig = &oid_old_orig;
 599        if (!get_oid("HEAD", &oid_orig)) {
 600                orig = &oid_orig;
 601                if (!reflog_orig_head) {
 602                        strbuf_addstr(&msg, "updating ORIG_HEAD");
 603                        reflog_orig_head = msg.buf;
 604                }
 605                update_ref(reflog_orig_head, "ORIG_HEAD", orig, old_orig, 0,
 606                           UPDATE_REFS_MSG_ON_ERR);
 607        } else if (old_orig)
 608                delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 609        if (!reflog_head) {
 610                strbuf_setlen(&msg, prefix_len);
 611                strbuf_addstr(&msg, "updating HEAD");
 612                reflog_head = msg.buf;
 613        }
 614        if (!switch_to_branch)
 615                ret = update_ref(reflog_head, "HEAD", oid, orig, REF_NO_DEREF,
 616                                 UPDATE_REFS_MSG_ON_ERR);
 617        else {
 618                ret = create_symref("HEAD", switch_to_branch, msg.buf);
 619                if (!ret)
 620                        ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
 621                                         UPDATE_REFS_MSG_ON_ERR);
 622        }
 623
 624        strbuf_release(&msg);
 625        return ret;
 626}
 627
 628static int rebase_config(const char *var, const char *value, void *data)
 629{
 630        struct rebase_options *opts = data;
 631
 632        if (!strcmp(var, "rebase.stat")) {
 633                if (git_config_bool(var, value))
 634                        opts->flags |= REBASE_DIFFSTAT;
 635                else
 636                        opts->flags &= !REBASE_DIFFSTAT;
 637                return 0;
 638        }
 639
 640        if (!strcmp(var, "rebase.autosquash")) {
 641                opts->autosquash = git_config_bool(var, value);
 642                return 0;
 643        }
 644
 645        if (!strcmp(var, "commit.gpgsign")) {
 646                free(opts->gpg_sign_opt);
 647                opts->gpg_sign_opt = git_config_bool(var, value) ?
 648                        xstrdup("-S") : NULL;
 649                return 0;
 650        }
 651
 652        if (!strcmp(var, "rebase.autostash")) {
 653                opts->autostash = git_config_bool(var, value);
 654                return 0;
 655        }
 656
 657        return git_default_config(var, value, data);
 658}
 659
 660/*
 661 * Determines whether the commits in from..to are linear, i.e. contain
 662 * no merge commits. This function *expects* `from` to be an ancestor of
 663 * `to`.
 664 */
 665static int is_linear_history(struct commit *from, struct commit *to)
 666{
 667        while (to && to != from) {
 668                parse_commit(to);
 669                if (!to->parents)
 670                        return 1;
 671                if (to->parents->next)
 672                        return 0;
 673                to = to->parents->item;
 674        }
 675        return 1;
 676}
 677
 678static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 679                            struct object_id *merge_base)
 680{
 681        struct commit *head = lookup_commit(the_repository, head_oid);
 682        struct commit_list *merge_bases;
 683        int res;
 684
 685        if (!head)
 686                return 0;
 687
 688        merge_bases = get_merge_bases(onto, head);
 689        if (merge_bases && !merge_bases->next) {
 690                oidcpy(merge_base, &merge_bases->item->object.oid);
 691                res = !oidcmp(merge_base, &onto->object.oid);
 692        } else {
 693                oidcpy(merge_base, &null_oid);
 694                res = 0;
 695        }
 696        free_commit_list(merge_bases);
 697        return res && is_linear_history(onto, head);
 698}
 699
 700/* -i followed by -m is still -i */
 701static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 702{
 703        struct rebase_options *opts = opt->value;
 704
 705        if (!is_interactive(opts))
 706                opts->type = REBASE_MERGE;
 707
 708        return 0;
 709}
 710
 711/* -i followed by -p is still explicitly interactive, but -p alone is not */
 712static int parse_opt_interactive(const struct option *opt, const char *arg,
 713                                 int unset)
 714{
 715        struct rebase_options *opts = opt->value;
 716
 717        opts->type = REBASE_INTERACTIVE;
 718        opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 719
 720        return 0;
 721}
 722
 723static void NORETURN error_on_missing_default_upstream(void)
 724{
 725        struct branch *current_branch = branch_get(NULL);
 726
 727        printf(_("%s\n"
 728                 "Please specify which branch you want to rebase against.\n"
 729                 "See git-rebase(1) for details.\n"
 730                 "\n"
 731                 "    git rebase '<branch>'\n"
 732                 "\n"),
 733                current_branch ? _("There is no tracking information for "
 734                        "the current branch.") :
 735                        _("You are not currently on a branch."));
 736
 737        if (current_branch) {
 738                const char *remote = current_branch->remote_name;
 739
 740                if (!remote)
 741                        remote = _("<remote>");
 742
 743                printf(_("If you wish to set tracking information for this "
 744                         "branch you can do so with:\n"
 745                         "\n"
 746                         "    git branch --set-upstream-to=%s/<branch> %s\n"
 747                         "\n"),
 748                       remote, current_branch->name);
 749        }
 750        exit(1);
 751}
 752
 753int cmd_rebase(int argc, const char **argv, const char *prefix)
 754{
 755        struct rebase_options options = {
 756                .type = REBASE_UNSPECIFIED,
 757                .flags = REBASE_NO_QUIET,
 758                .git_am_opt = STRBUF_INIT,
 759                .allow_rerere_autoupdate  = -1,
 760                .allow_empty_message = 1,
 761                .git_format_patch_opt = STRBUF_INIT,
 762        };
 763        const char *branch_name;
 764        int ret, flags, total_argc, in_progress = 0;
 765        int ok_to_skip_pre_rebase = 0;
 766        struct strbuf msg = STRBUF_INIT;
 767        struct strbuf revisions = STRBUF_INIT;
 768        struct strbuf buf = STRBUF_INIT;
 769        struct object_id merge_base;
 770        enum {
 771                NO_ACTION,
 772                ACTION_CONTINUE,
 773                ACTION_SKIP,
 774                ACTION_ABORT,
 775                ACTION_QUIT,
 776                ACTION_EDIT_TODO,
 777                ACTION_SHOW_CURRENT_PATCH,
 778        } action = NO_ACTION;
 779        int committer_date_is_author_date = 0;
 780        int ignore_date = 0;
 781        int ignore_whitespace = 0;
 782        const char *gpg_sign = NULL;
 783        int opt_c = -1;
 784        struct string_list whitespace = STRING_LIST_INIT_NODUP;
 785        struct string_list exec = STRING_LIST_INIT_NODUP;
 786        const char *rebase_merges = NULL;
 787        int fork_point = -1;
 788        struct string_list strategy_options = STRING_LIST_INIT_NODUP;
 789        struct object_id squash_onto;
 790        char *squash_onto_name = NULL;
 791        struct option builtin_rebase_options[] = {
 792                OPT_STRING(0, "onto", &options.onto_name,
 793                           N_("revision"),
 794                           N_("rebase onto given branch instead of upstream")),
 795                OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 796                         N_("allow pre-rebase hook to run")),
 797                OPT_NEGBIT('q', "quiet", &options.flags,
 798                           N_("be quiet. implies --no-stat"),
 799                           REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 800                OPT_BIT('v', "verbose", &options.flags,
 801                        N_("display a diffstat of what changed upstream"),
 802                        REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 803                {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 804                        N_("do not show diffstat of what changed upstream"),
 805                        PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 806                OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
 807                         N_("passed to 'git apply'")),
 808                OPT_BOOL(0, "signoff", &options.signoff,
 809                         N_("add a Signed-off-by: line to each commit")),
 810                OPT_BOOL(0, "committer-date-is-author-date",
 811                         &committer_date_is_author_date,
 812                         N_("passed to 'git am'")),
 813                OPT_BOOL(0, "ignore-date", &ignore_date,
 814                         N_("passed to 'git am'")),
 815                OPT_BIT('f', "force-rebase", &options.flags,
 816                        N_("cherry-pick all commits, even if unchanged"),
 817                        REBASE_FORCE),
 818                OPT_BIT(0, "no-ff", &options.flags,
 819                        N_("cherry-pick all commits, even if unchanged"),
 820                        REBASE_FORCE),
 821                OPT_CMDMODE(0, "continue", &action, N_("continue"),
 822                            ACTION_CONTINUE),
 823                OPT_CMDMODE(0, "skip", &action,
 824                            N_("skip current patch and continue"), ACTION_SKIP),
 825                OPT_CMDMODE(0, "abort", &action,
 826                            N_("abort and check out the original branch"),
 827                            ACTION_ABORT),
 828                OPT_CMDMODE(0, "quit", &action,
 829                            N_("abort but keep HEAD where it is"), ACTION_QUIT),
 830                OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
 831                            "during an interactive rebase"), ACTION_EDIT_TODO),
 832                OPT_CMDMODE(0, "show-current-patch", &action,
 833                            N_("show the patch file being applied or merged"),
 834                            ACTION_SHOW_CURRENT_PATCH),
 835                { OPTION_CALLBACK, 'm', "merge", &options, NULL,
 836                        N_("use merging strategies to rebase"),
 837                        PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 838                        parse_opt_merge },
 839                { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
 840                        N_("let the user edit the list of commits to rebase"),
 841                        PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 842                        parse_opt_interactive },
 843                OPT_SET_INT('p', "preserve-merges", &options.type,
 844                            N_("try to recreate merges instead of ignoring "
 845                               "them"), REBASE_PRESERVE_MERGES),
 846                OPT_BOOL(0, "rerere-autoupdate",
 847                         &options.allow_rerere_autoupdate,
 848                         N_("allow rerere to update index  with resolved "
 849                            "conflict")),
 850                OPT_BOOL('k', "keep-empty", &options.keep_empty,
 851                         N_("preserve empty commits during rebase")),
 852                OPT_BOOL(0, "autosquash", &options.autosquash,
 853                         N_("move commits that begin with "
 854                            "squash!/fixup! under -i")),
 855                { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 856                        N_("GPG-sign commits"),
 857                        PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 858                OPT_STRING_LIST(0, "whitespace", &whitespace,
 859                                N_("whitespace"), N_("passed to 'git apply'")),
 860                OPT_SET_INT('C', NULL, &opt_c, N_("passed to 'git apply'"),
 861                            REBASE_AM),
 862                OPT_BOOL(0, "autostash", &options.autostash,
 863                         N_("automatically stash/stash pop before and after")),
 864                OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
 865                                N_("add exec lines after each commit of the "
 866                                   "editable list")),
 867                OPT_BOOL(0, "allow-empty-message",
 868                         &options.allow_empty_message,
 869                         N_("allow rebasing commits with empty messages")),
 870                {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
 871                        N_("mode"),
 872                        N_("try to rebase merges instead of skipping them"),
 873                        PARSE_OPT_OPTARG, NULL, (intptr_t)""},
 874                OPT_BOOL(0, "fork-point", &fork_point,
 875                         N_("use 'merge-base --fork-point' to refine upstream")),
 876                OPT_STRING('s', "strategy", &options.strategy,
 877                           N_("strategy"), N_("use the given merge strategy")),
 878                OPT_STRING_LIST('X', "strategy-option", &strategy_options,
 879                                N_("option"),
 880                                N_("pass the argument through to the merge "
 881                                   "strategy")),
 882                OPT_BOOL(0, "root", &options.root,
 883                         N_("rebase all reachable commits up to the root(s)")),
 884                OPT_END(),
 885        };
 886
 887        /*
 888         * NEEDSWORK: Once the builtin rebase has been tested enough
 889         * and git-legacy-rebase.sh is retired to contrib/, this preamble
 890         * can be removed.
 891         */
 892
 893        if (!use_builtin_rebase()) {
 894                const char *path = mkpath("%s/git-legacy-rebase",
 895                                          git_exec_path());
 896
 897                if (sane_execvp(path, (char **)argv) < 0)
 898                        die_errno(_("could not exec %s"), path);
 899                else
 900                        BUG("sane_execvp() returned???");
 901        }
 902
 903        if (argc == 2 && !strcmp(argv[1], "-h"))
 904                usage_with_options(builtin_rebase_usage,
 905                                   builtin_rebase_options);
 906
 907        prefix = setup_git_directory();
 908        trace_repo_setup(prefix);
 909        setup_work_tree();
 910
 911        git_config(rebase_config, &options);
 912
 913        strbuf_reset(&buf);
 914        strbuf_addf(&buf, "%s/applying", apply_dir());
 915        if(file_exists(buf.buf))
 916                die(_("It looks like 'git am' is in progress. Cannot rebase."));
 917
 918        if (is_directory(apply_dir())) {
 919                options.type = REBASE_AM;
 920                options.state_dir = apply_dir();
 921        } else if (is_directory(merge_dir())) {
 922                strbuf_reset(&buf);
 923                strbuf_addf(&buf, "%s/rewritten", merge_dir());
 924                if (is_directory(buf.buf)) {
 925                        options.type = REBASE_PRESERVE_MERGES;
 926                        options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 927                } else {
 928                        strbuf_reset(&buf);
 929                        strbuf_addf(&buf, "%s/interactive", merge_dir());
 930                        if(file_exists(buf.buf)) {
 931                                options.type = REBASE_INTERACTIVE;
 932                                options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 933                        } else
 934                                options.type = REBASE_MERGE;
 935                }
 936                options.state_dir = merge_dir();
 937        }
 938
 939        if (options.type != REBASE_UNSPECIFIED)
 940                in_progress = 1;
 941
 942        total_argc = argc;
 943        argc = parse_options(argc, argv, prefix,
 944                             builtin_rebase_options,
 945                             builtin_rebase_usage, 0);
 946
 947        if (action != NO_ACTION && total_argc != 2) {
 948                usage_with_options(builtin_rebase_usage,
 949                                   builtin_rebase_options);
 950        }
 951
 952        if (argc > 2)
 953                usage_with_options(builtin_rebase_usage,
 954                                   builtin_rebase_options);
 955
 956        if (action != NO_ACTION && !in_progress)
 957                die(_("No rebase in progress?"));
 958
 959        if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 960                die(_("The --edit-todo action can only be used during "
 961                      "interactive rebase."));
 962
 963        switch (action) {
 964        case ACTION_CONTINUE: {
 965                struct object_id head;
 966                struct lock_file lock_file = LOCK_INIT;
 967                int fd;
 968
 969                options.action = "continue";
 970
 971                /* Sanity check */
 972                if (get_oid("HEAD", &head))
 973                        die(_("Cannot read HEAD"));
 974
 975                fd = hold_locked_index(&lock_file, 0);
 976                if (read_index(the_repository->index) < 0)
 977                        die(_("could not read index"));
 978                refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 979                              NULL);
 980                if (0 <= fd)
 981                        update_index_if_able(the_repository->index,
 982                                             &lock_file);
 983                rollback_lock_file(&lock_file);
 984
 985                if (has_unstaged_changes(1)) {
 986                        puts(_("You must edit all merge conflicts and then\n"
 987                               "mark them as resolved using git add"));
 988                        exit(1);
 989                }
 990                if (read_basic_state(&options))
 991                        exit(1);
 992                goto run_rebase;
 993        }
 994        case ACTION_SKIP: {
 995                struct string_list merge_rr = STRING_LIST_INIT_DUP;
 996
 997                options.action = "skip";
 998
 999                rerere_clear(&merge_rr);
1000                string_list_clear(&merge_rr, 1);
1001
1002                if (reset_head(NULL, "reset", NULL, 0, NULL, NULL) < 0)
1003                        die(_("could not discard worktree changes"));
1004                if (read_basic_state(&options))
1005                        exit(1);
1006                goto run_rebase;
1007        }
1008        case ACTION_ABORT: {
1009                struct string_list merge_rr = STRING_LIST_INIT_DUP;
1010                options.action = "abort";
1011
1012                rerere_clear(&merge_rr);
1013                string_list_clear(&merge_rr, 1);
1014
1015                if (read_basic_state(&options))
1016                        exit(1);
1017                if (reset_head(&options.orig_head, "reset",
1018                               options.head_name, 0, NULL, NULL) < 0)
1019                        die(_("could not move back to %s"),
1020                            oid_to_hex(&options.orig_head));
1021                ret = finish_rebase(&options);
1022                goto cleanup;
1023        }
1024        case ACTION_QUIT: {
1025                strbuf_reset(&buf);
1026                strbuf_addstr(&buf, options.state_dir);
1027                ret = !!remove_dir_recursively(&buf, 0);
1028                if (ret)
1029                        die(_("could not remove '%s'"), options.state_dir);
1030                goto cleanup;
1031        }
1032        case ACTION_EDIT_TODO:
1033                options.action = "edit-todo";
1034                options.dont_finish_rebase = 1;
1035                goto run_rebase;
1036        case ACTION_SHOW_CURRENT_PATCH:
1037                options.action = "show-current-patch";
1038                options.dont_finish_rebase = 1;
1039                goto run_rebase;
1040        case NO_ACTION:
1041                break;
1042        default:
1043                BUG("action: %d", action);
1044        }
1045
1046        /* Make sure no rebase is in progress */
1047        if (in_progress) {
1048                const char *last_slash = strrchr(options.state_dir, '/');
1049                const char *state_dir_base =
1050                        last_slash ? last_slash + 1 : options.state_dir;
1051                const char *cmd_live_rebase =
1052                        "git rebase (--continue | --abort | --skip)";
1053                strbuf_reset(&buf);
1054                strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1055                die(_("It seems that there is already a %s directory, and\n"
1056                      "I wonder if you are in the middle of another rebase.  "
1057                      "If that is the\n"
1058                      "case, please try\n\t%s\n"
1059                      "If that is not the case, please\n\t%s\n"
1060                      "and run me again.  I am stopping in case you still "
1061                      "have something\n"
1062                      "valuable there.\n"),
1063                    state_dir_base, cmd_live_rebase, buf.buf);
1064        }
1065
1066        if (!(options.flags & REBASE_NO_QUIET))
1067                strbuf_addstr(&options.git_am_opt, " -q");
1068
1069        if (committer_date_is_author_date) {
1070                strbuf_addstr(&options.git_am_opt,
1071                              " --committer-date-is-author-date");
1072                options.flags |= REBASE_FORCE;
1073        }
1074
1075        if (ignore_whitespace)
1076                strbuf_addstr(&options.git_am_opt, " --ignore-whitespace");
1077
1078        if (ignore_date) {
1079                strbuf_addstr(&options.git_am_opt, " --ignore-date");
1080                options.flags |= REBASE_FORCE;
1081        }
1082
1083        if (options.keep_empty)
1084                imply_interactive(&options, "--keep-empty");
1085
1086        if (gpg_sign) {
1087                free(options.gpg_sign_opt);
1088                options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1089        }
1090
1091        if (opt_c >= 0)
1092                strbuf_addf(&options.git_am_opt, " -C%d", opt_c);
1093
1094        if (whitespace.nr) {
1095                int i;
1096
1097                for (i = 0; i < whitespace.nr; i++) {
1098                        const char *item = whitespace.items[i].string;
1099
1100                        strbuf_addf(&options.git_am_opt, " --whitespace=%s",
1101                                    item);
1102
1103                        if ((!strcmp(item, "fix")) || (!strcmp(item, "strip")))
1104                                options.flags |= REBASE_FORCE;
1105                }
1106        }
1107
1108        if (exec.nr) {
1109                int i;
1110
1111                imply_interactive(&options, "--exec");
1112
1113                strbuf_reset(&buf);
1114                for (i = 0; i < exec.nr; i++)
1115                        strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1116                options.cmd = xstrdup(buf.buf);
1117        }
1118
1119        if (rebase_merges) {
1120                if (!*rebase_merges)
1121                        ; /* default mode; do nothing */
1122                else if (!strcmp("rebase-cousins", rebase_merges))
1123                        options.rebase_cousins = 1;
1124                else if (strcmp("no-rebase-cousins", rebase_merges))
1125                        die(_("Unknown mode: %s"), rebase_merges);
1126                options.rebase_merges = 1;
1127                imply_interactive(&options, "--rebase-merges");
1128        }
1129
1130        if (strategy_options.nr) {
1131                int i;
1132
1133                if (!options.strategy)
1134                        options.strategy = "recursive";
1135
1136                strbuf_reset(&buf);
1137                for (i = 0; i < strategy_options.nr; i++)
1138                        strbuf_addf(&buf, " --%s",
1139                                    strategy_options.items[i].string);
1140                options.strategy_opts = xstrdup(buf.buf);
1141        }
1142
1143        if (options.strategy) {
1144                options.strategy = xstrdup(options.strategy);
1145                switch (options.type) {
1146                case REBASE_AM:
1147                        die(_("--strategy requires --merge or --interactive"));
1148                case REBASE_MERGE:
1149                case REBASE_INTERACTIVE:
1150                case REBASE_PRESERVE_MERGES:
1151                        /* compatible */
1152                        break;
1153                case REBASE_UNSPECIFIED:
1154                        options.type = REBASE_MERGE;
1155                        break;
1156                default:
1157                        BUG("unhandled rebase type (%d)", options.type);
1158                }
1159        }
1160
1161        if (options.root && !options.onto_name)
1162                imply_interactive(&options, "--root without --onto");
1163
1164        if (isatty(2) && options.flags & REBASE_NO_QUIET)
1165                strbuf_addstr(&options.git_format_patch_opt, " --progress");
1166
1167        switch (options.type) {
1168        case REBASE_MERGE:
1169        case REBASE_INTERACTIVE:
1170        case REBASE_PRESERVE_MERGES:
1171                options.state_dir = merge_dir();
1172                break;
1173        case REBASE_AM:
1174                options.state_dir = apply_dir();
1175                break;
1176        default:
1177                /* the default rebase backend is `--am` */
1178                options.type = REBASE_AM;
1179                options.state_dir = apply_dir();
1180                break;
1181        }
1182
1183        if (options.git_am_opt.len) {
1184                const char *p;
1185
1186                /* all am options except -q are compatible only with --am */
1187                strbuf_reset(&buf);
1188                strbuf_addbuf(&buf, &options.git_am_opt);
1189                strbuf_addch(&buf, ' ');
1190                while ((p = strstr(buf.buf, " -q ")))
1191                        strbuf_splice(&buf, p - buf.buf, 4, " ", 1);
1192                strbuf_trim(&buf);
1193
1194                if (is_interactive(&options) && buf.len)
1195                        die(_("error: cannot combine interactive options "
1196                              "(--interactive, --exec, --rebase-merges, "
1197                              "--preserve-merges, --keep-empty, --root + "
1198                              "--onto) with am options (%s)"), buf.buf);
1199                if (options.type == REBASE_MERGE && buf.len)
1200                        die(_("error: cannot combine merge options (--merge, "
1201                              "--strategy, --strategy-option) with am options "
1202                              "(%s)"), buf.buf);
1203        }
1204
1205        if (options.signoff) {
1206                if (options.type == REBASE_PRESERVE_MERGES)
1207                        die("cannot combine '--signoff' with "
1208                            "'--preserve-merges'");
1209                strbuf_addstr(&options.git_am_opt, " --signoff");
1210                options.flags |= REBASE_FORCE;
1211        }
1212
1213        if (options.type == REBASE_PRESERVE_MERGES)
1214                /*
1215                 * Note: incompatibility with --signoff handled in signoff block above
1216                 * Note: incompatibility with --interactive is just a strong warning;
1217                 *       git-rebase.txt caveats with "unless you know what you are doing"
1218                 */
1219                if (options.rebase_merges)
1220                        die(_("error: cannot combine '--preserve_merges' with "
1221                              "'--rebase-merges'"));
1222
1223        if (options.rebase_merges) {
1224                if (strategy_options.nr)
1225                        die(_("error: cannot combine '--rebase_merges' with "
1226                              "'--strategy-option'"));
1227                if (options.strategy)
1228                        die(_("error: cannot combine '--rebase_merges' with "
1229                              "'--strategy'"));
1230        }
1231
1232        if (!options.root) {
1233                if (argc < 1) {
1234                        struct branch *branch;
1235
1236                        branch = branch_get(NULL);
1237                        options.upstream_name = branch_get_upstream(branch,
1238                                                                    NULL);
1239                        if (!options.upstream_name)
1240                                error_on_missing_default_upstream();
1241                        if (fork_point < 0)
1242                                fork_point = 1;
1243                } else {
1244                        options.upstream_name = argv[0];
1245                        argc--;
1246                        argv++;
1247                        if (!strcmp(options.upstream_name, "-"))
1248                                options.upstream_name = "@{-1}";
1249                }
1250                options.upstream = peel_committish(options.upstream_name);
1251                if (!options.upstream)
1252                        die(_("invalid upstream '%s'"), options.upstream_name);
1253                options.upstream_arg = options.upstream_name;
1254        } else {
1255                if (!options.onto_name) {
1256                        if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1257                                        &squash_onto, NULL, NULL) < 0)
1258                                die(_("Could not create new root commit"));
1259                        options.squash_onto = &squash_onto;
1260                        options.onto_name = squash_onto_name =
1261                                xstrdup(oid_to_hex(&squash_onto));
1262                }
1263                options.upstream_name = NULL;
1264                options.upstream = NULL;
1265                if (argc > 1)
1266                        usage_with_options(builtin_rebase_usage,
1267                                           builtin_rebase_options);
1268                options.upstream_arg = "--root";
1269        }
1270
1271        /* Make sure the branch to rebase onto is valid. */
1272        if (!options.onto_name)
1273                options.onto_name = options.upstream_name;
1274        if (strstr(options.onto_name, "...")) {
1275                if (get_oid_mb(options.onto_name, &merge_base) < 0)
1276                        die(_("'%s': need exactly one merge base"),
1277                            options.onto_name);
1278                options.onto = lookup_commit_or_die(&merge_base,
1279                                                    options.onto_name);
1280        } else {
1281                options.onto = peel_committish(options.onto_name);
1282                if (!options.onto)
1283                        die(_("Does not point to a valid commit '%s'"),
1284                                options.onto_name);
1285        }
1286
1287        /*
1288         * If the branch to rebase is given, that is the branch we will rebase
1289         * branch_name -- branch/commit being rebased, or
1290         *                HEAD (already detached)
1291         * orig_head -- commit object name of tip of the branch before rebasing
1292         * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1293         */
1294        if (argc == 1) {
1295                /* Is it "rebase other branchname" or "rebase other commit"? */
1296                branch_name = argv[0];
1297                options.switch_to = argv[0];
1298
1299                /* Is it a local branch? */
1300                strbuf_reset(&buf);
1301                strbuf_addf(&buf, "refs/heads/%s", branch_name);
1302                if (!read_ref(buf.buf, &options.orig_head))
1303                        options.head_name = xstrdup(buf.buf);
1304                /* If not is it a valid ref (branch or commit)? */
1305                else if (!get_oid(branch_name, &options.orig_head))
1306                        options.head_name = NULL;
1307                else
1308                        die(_("fatal: no such branch/commit '%s'"),
1309                            branch_name);
1310        } else if (argc == 0) {
1311                /* Do not need to switch branches, we are already on it. */
1312                options.head_name =
1313                        xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1314                                         &flags));
1315                if (!options.head_name)
1316                        die(_("No such ref: %s"), "HEAD");
1317                if (flags & REF_ISSYMREF) {
1318                        if (!skip_prefix(options.head_name,
1319                                         "refs/heads/", &branch_name))
1320                                branch_name = options.head_name;
1321
1322                } else {
1323                        free(options.head_name);
1324                        options.head_name = NULL;
1325                        branch_name = "HEAD";
1326                }
1327                if (get_oid("HEAD", &options.orig_head))
1328                        die(_("Could not resolve HEAD to a revision"));
1329        } else
1330                BUG("unexpected number of arguments left to parse");
1331
1332        if (fork_point > 0) {
1333                struct commit *head =
1334                        lookup_commit_reference(the_repository,
1335                                                &options.orig_head);
1336                options.restrict_revision =
1337                        get_fork_point(options.upstream_name, head);
1338        }
1339
1340        if (read_index(the_repository->index) < 0)
1341                die(_("could not read index"));
1342
1343        if (options.autostash) {
1344                struct lock_file lock_file = LOCK_INIT;
1345                int fd;
1346
1347                fd = hold_locked_index(&lock_file, 0);
1348                refresh_cache(REFRESH_QUIET);
1349                if (0 <= fd)
1350                        update_index_if_able(&the_index, &lock_file);
1351                rollback_lock_file(&lock_file);
1352
1353                if (has_unstaged_changes(1) || has_uncommitted_changes(1)) {
1354                        const char *autostash =
1355                                state_dir_path("autostash", &options);
1356                        struct child_process stash = CHILD_PROCESS_INIT;
1357                        struct object_id oid;
1358                        struct commit *head =
1359                                lookup_commit_reference(the_repository,
1360                                                        &options.orig_head);
1361
1362                        argv_array_pushl(&stash.args,
1363                                         "stash", "create", "autostash", NULL);
1364                        stash.git_cmd = 1;
1365                        stash.no_stdin = 1;
1366                        strbuf_reset(&buf);
1367                        if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
1368                                die(_("Cannot autostash"));
1369                        strbuf_trim_trailing_newline(&buf);
1370                        if (get_oid(buf.buf, &oid))
1371                                die(_("Unexpected stash response: '%s'"),
1372                                    buf.buf);
1373                        strbuf_reset(&buf);
1374                        strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
1375
1376                        if (safe_create_leading_directories_const(autostash))
1377                                die(_("Could not create directory for '%s'"),
1378                                    options.state_dir);
1379                        write_file(autostash, "%s", oid_to_hex(&oid));
1380                        printf(_("Created autostash: %s\n"), buf.buf);
1381                        if (reset_head(&head->object.oid, "reset --hard",
1382                                       NULL, 0, NULL, NULL) < 0)
1383                                die(_("could not reset --hard"));
1384                        printf(_("HEAD is now at %s"),
1385                               find_unique_abbrev(&head->object.oid,
1386                                                  DEFAULT_ABBREV));
1387                        strbuf_reset(&buf);
1388                        pp_commit_easy(CMIT_FMT_ONELINE, head, &buf);
1389                        if (buf.len > 0)
1390                                printf(" %s", buf.buf);
1391                        putchar('\n');
1392
1393                        if (discard_index(the_repository->index) < 0 ||
1394                                read_index(the_repository->index) < 0)
1395                                die(_("could not read index"));
1396                }
1397        }
1398
1399        if (require_clean_work_tree("rebase",
1400                                    _("Please commit or stash them."), 1, 1)) {
1401                ret = 1;
1402                goto cleanup;
1403        }
1404
1405        /*
1406         * Now we are rebasing commits upstream..orig_head (or with --root,
1407         * everything leading up to orig_head) on top of onto.
1408         */
1409
1410        /*
1411         * Check if we are already based on onto with linear history,
1412         * but this should be done only when upstream and onto are the same
1413         * and if this is not an interactive rebase.
1414         */
1415        if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
1416            !is_interactive(&options) && !options.restrict_revision &&
1417            options.upstream &&
1418            !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
1419                int flag;
1420
1421                if (!(options.flags & REBASE_FORCE)) {
1422                        /* Lazily switch to the target branch if needed... */
1423                        if (options.switch_to) {
1424                                struct object_id oid;
1425
1426                                if (get_oid(options.switch_to, &oid) < 0) {
1427                                        ret = !!error(_("could not parse '%s'"),
1428                                                      options.switch_to);
1429                                        goto cleanup;
1430                                }
1431
1432                                strbuf_reset(&buf);
1433                                strbuf_addf(&buf, "rebase: checkout %s",
1434                                            options.switch_to);
1435                                if (reset_head(&oid, "checkout",
1436                                               options.head_name, 0,
1437                                               NULL, NULL) < 0) {
1438                                        ret = !!error(_("could not switch to "
1439                                                        "%s"),
1440                                                      options.switch_to);
1441                                        goto cleanup;
1442                                }
1443                        }
1444
1445                        if (!(options.flags & REBASE_NO_QUIET))
1446                                ; /* be quiet */
1447                        else if (!strcmp(branch_name, "HEAD") &&
1448                                 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1449                                puts(_("HEAD is up to date."));
1450                        else
1451                                printf(_("Current branch %s is up to date.\n"),
1452                                       branch_name);
1453                        ret = !!finish_rebase(&options);
1454                        goto cleanup;
1455                } else if (!(options.flags & REBASE_NO_QUIET))
1456                        ; /* be quiet */
1457                else if (!strcmp(branch_name, "HEAD") &&
1458                         resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1459                        puts(_("HEAD is up to date, rebase forced."));
1460                else
1461                        printf(_("Current branch %s is up to date, rebase "
1462                                 "forced.\n"), branch_name);
1463        }
1464
1465        /* If a hook exists, give it a chance to interrupt*/
1466        if (!ok_to_skip_pre_rebase &&
1467            run_hook_le(NULL, "pre-rebase", options.upstream_arg,
1468                        argc ? argv[0] : NULL, NULL))
1469                die(_("The pre-rebase hook refused to rebase."));
1470
1471        if (options.flags & REBASE_DIFFSTAT) {
1472                struct diff_options opts;
1473
1474                if (options.flags & REBASE_VERBOSE)
1475                        printf(_("Changes from %s to %s:\n"),
1476                                oid_to_hex(&merge_base),
1477                                oid_to_hex(&options.onto->object.oid));
1478
1479                /* We want color (if set), but no pager */
1480                diff_setup(&opts);
1481                opts.stat_width = -1; /* use full terminal width */
1482                opts.stat_graph_width = -1; /* respect statGraphWidth config */
1483                opts.output_format |=
1484                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
1485                opts.detect_rename = DIFF_DETECT_RENAME;
1486                diff_setup_done(&opts);
1487                diff_tree_oid(&merge_base, &options.onto->object.oid,
1488                              "", &opts);
1489                diffcore_std(&opts);
1490                diff_flush(&opts);
1491        }
1492
1493        if (is_interactive(&options))
1494                goto run_rebase;
1495
1496        /* Detach HEAD and reset the tree */
1497        if (options.flags & REBASE_NO_QUIET)
1498                printf(_("First, rewinding head to replay your work on top of "
1499                         "it...\n"));
1500
1501        strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
1502        if (reset_head(&options.onto->object.oid, "checkout", NULL, 1,
1503            NULL, msg.buf))
1504                die(_("Could not detach HEAD"));
1505        strbuf_release(&msg);
1506
1507        /*
1508         * If the onto is a proper descendant of the tip of the branch, then
1509         * we just fast-forwarded.
1510         */
1511        strbuf_reset(&msg);
1512        if (!oidcmp(&merge_base, &options.orig_head)) {
1513                printf(_("Fast-forwarded %s to %s. \n"),
1514                        branch_name, options.onto_name);
1515                strbuf_addf(&msg, "rebase finished: %s onto %s",
1516                        options.head_name ? options.head_name : "detached HEAD",
1517                        oid_to_hex(&options.onto->object.oid));
1518                reset_head(NULL, "Fast-forwarded", options.head_name, 0,
1519                           "HEAD", msg.buf);
1520                strbuf_release(&msg);
1521                ret = !!finish_rebase(&options);
1522                goto cleanup;
1523        }
1524
1525        strbuf_addf(&revisions, "%s..%s",
1526                    options.root ? oid_to_hex(&options.onto->object.oid) :
1527                    (options.restrict_revision ?
1528                     oid_to_hex(&options.restrict_revision->object.oid) :
1529                     oid_to_hex(&options.upstream->object.oid)),
1530                    oid_to_hex(&options.orig_head));
1531
1532        options.revisions = revisions.buf;
1533
1534run_rebase:
1535        ret = !!run_specific_rebase(&options);
1536
1537cleanup:
1538        strbuf_release(&revisions);
1539        free(options.head_name);
1540        free(options.gpg_sign_opt);
1541        free(options.cmd);
1542        free(squash_onto_name);
1543        return ret;
1544}