builtin/rebase.c

   1 /*
   2  * "git rebase" builtin command
   3  *
   4  * Copyright (c) 2018 Pratik Karki
   5  */
   6
   7 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   8 #include "builtin.h"
   9 #include "run-command.h"
  10 #include "exec-cmd.h"
  11 #include "argv-array.h"
  12 #include "dir.h"
  13 #include "packfile.h"
  14 #include "refs.h"
  15 #include "quote.h"
  16 #include "config.h"
  17 #include "cache-tree.h"
  18 #include "unpack-trees.h"
  19 #include "lockfile.h"
  20 #include "parse-options.h"
  21 #include "commit.h"
  22 #include "diff.h"
  23 #include "wt-status.h"
  24 #include "revision.h"
  25 #include "commit-reach.h"
  26 #include "rerere.h"
  27 #include "branch.h"
  28
  29 static char const * const builtin_rebase_usage[] = {
  30         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  31                 "[<upstream>] [<branch>]"),
  32         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  33                 "--root [<branch>]"),
  34         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  35         NULL
  36 };
  37
  38 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  39 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  40
  41 enum rebase_type {
  42         REBASE_UNSPECIFIED = -1,
  43         REBASE_AM,
  44         REBASE_MERGE,
  45         REBASE_INTERACTIVE,
  46         REBASE_PRESERVE_MERGES
  47 };
  48
  49 static int use_builtin_rebase(void)
  50 {
  51         struct child_process cp = CHILD_PROCESS_INIT;
  52         struct strbuf out = STRBUF_INIT;
  53         int ret, env = git_env_bool("GIT_TEST_REBASE_USE_BUILTIN", -1);
  54
  55         if (env != -1)
  56                 return env;
  57
  58         argv_array_pushl(&cp.args,
  59                          "config", "--bool", "rebase.usebuiltin", NULL);
  60         cp.git_cmd = 1;
  61         if (capture_command(&cp, &out, 6)) {
  62                 strbuf_release(&out);
  63                 return 1;
  64         }
  65
  66         strbuf_trim(&out);
  67         ret = !strcmp("true", out.buf);
  68         strbuf_release(&out);
  69         return ret;
  70 }
  71
  72 struct rebase_options {
  73         enum rebase_type type;
  74         const char *state_dir;
  75         struct commit *upstream;
  76         const char *upstream_name;
  77         const char *upstream_arg;
  78         char *head_name;
  79         struct object_id orig_head;
  80         struct commit *onto;
  81         const char *onto_name;
  82         const char *revisions;
  83         const char *switch_to;
  84         int root;
  85         struct object_id *squash_onto;
  86         struct commit *restrict_revision;
  87         int dont_finish_rebase;
  88         enum {
  89                 REBASE_NO_QUIET = 1<<0,
  90                 REBASE_VERBOSE = 1<<1,
  91                 REBASE_DIFFSTAT = 1<<2,
  92                 REBASE_FORCE = 1<<3,
  93                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  94         } flags;
  95         struct argv_array git_am_opts;
  96         const char *action;
  97         int signoff;
  98         int allow_rerere_autoupdate;
  99         int keep_empty;
 100         int autosquash;
 101         char *gpg_sign_opt;
 102         int autostash;
 103         char *cmd;
 104         int allow_empty_message;
 105         int rebase_merges, rebase_cousins;
 106         char *strategy, *strategy_opts;
 107         struct strbuf git_format_patch_opt;
 108         int reschedule_failed_exec;
 109 };
 110
 111 static int is_interactive(struct rebase_options *opts)
 112 {
 113         return opts->type == REBASE_INTERACTIVE ||
 114                 opts->type == REBASE_PRESERVE_MERGES;
 115 }
 116
 117 static void imply_interactive(struct rebase_options *opts, const char *option)
 118 {
 119         switch (opts->type) {
 120         case REBASE_AM:
 121                 die(_("%s requires an interactive rebase"), option);
 122                 break;
 123         case REBASE_INTERACTIVE:
 124         case REBASE_PRESERVE_MERGES:
 125                 break;
 126         case REBASE_MERGE:
 127                 /* we now implement --merge via --interactive */
 128         default:
 129                 opts->type = REBASE_INTERACTIVE; /* implied */
 130                 break;
 131         }
 132 }
 133
 134 /* Returns the filename prefixed by the state_dir */
 135 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 136 {
 137         static struct strbuf path = STRBUF_INIT;
 138         static size_t prefix_len;
 139
 140         if (!prefix_len) {
 141                 strbuf_addf(&path, "%s/", opts->state_dir);
 142                 prefix_len = path.len;
 143         }
 144
 145         strbuf_setlen(&path, prefix_len);
 146         strbuf_addstr(&path, filename);
 147         return path.buf;
 148 }
 149
 150 /* Read one file, then strip line endings */
 151 static int read_one(const char *path, struct strbuf *buf)
 152 {
 153         if (strbuf_read_file(buf, path, 0) < 0)
 154                 return error_errno(_("could not read '%s'"), path);
 155         strbuf_trim_trailing_newline(buf);
 156         return 0;
 157 }
 158
 159 /* Initialize the rebase options from the state directory. */
 160 static int read_basic_state(struct rebase_options *opts)
 161 {
 162         struct strbuf head_name = STRBUF_INIT;
 163         struct strbuf buf = STRBUF_INIT;
 164         struct object_id oid;
 165
 166         if (read_one(state_dir_path("head-name", opts), &head_name) ||
 167             read_one(state_dir_path("onto", opts), &buf))
 168                 return -1;
 169         opts->head_name = starts_with(head_name.buf, "refs/") ?
 170                 xstrdup(head_name.buf) : NULL;
 171         strbuf_release(&head_name);
 172         if (get_oid(buf.buf, &oid))
 173                 return error(_("could not get 'onto': '%s'"), buf.buf);
 174         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 175
 176         /*
 177          * We always write to orig-head, but interactive rebase used to write to
 178          * head. Fall back to reading from head to cover for the case that the
 179          * user upgraded git with an ongoing interactive rebase.
 180          */
 181         strbuf_reset(&buf);
 182         if (file_exists(state_dir_path("orig-head", opts))) {
 183                 if (read_one(state_dir_path("orig-head", opts), &buf))
 184                         return -1;
 185         } else if (read_one(state_dir_path("head", opts), &buf))
 186                 return -1;
 187         if (get_oid(buf.buf, &opts->orig_head))
 188                 return error(_("invalid orig-head: '%s'"), buf.buf);
 189
 190         if (file_exists(state_dir_path("quiet", opts)))
 191                 opts->flags &= ~REBASE_NO_QUIET;
 192         else
 193                 opts->flags |= REBASE_NO_QUIET;
 194
 195         if (file_exists(state_dir_path("verbose", opts)))
 196                 opts->flags |= REBASE_VERBOSE;
 197
 198         if (file_exists(state_dir_path("signoff", opts))) {
 199                 opts->signoff = 1;
 200                 opts->flags |= REBASE_FORCE;
 201         }
 202
 203         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 204                 strbuf_reset(&buf);
 205                 if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
 206                             &buf))
 207                         return -1;
 208                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
 209                         opts->allow_rerere_autoupdate = 1;
 210                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 211                         opts->allow_rerere_autoupdate = 0;
 212                 else
 213                         warning(_("ignoring invalid allow_rerere_autoupdate: "
 214                                   "'%s'"), buf.buf);
 215         } else
 216                 opts->allow_rerere_autoupdate = -1;
 217
 218         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 219                 strbuf_reset(&buf);
 220                 if (read_one(state_dir_path("gpg_sign_opt", opts),
 221                             &buf))
 222                         return -1;
 223                 free(opts->gpg_sign_opt);
 224                 opts->gpg_sign_opt = xstrdup(buf.buf);
 225         }
 226
 227         if (file_exists(state_dir_path("strategy", opts))) {
 228                 strbuf_reset(&buf);
 229                 if (read_one(state_dir_path("strategy", opts), &buf))
 230                         return -1;
 231                 free(opts->strategy);
 232                 opts->strategy = xstrdup(buf.buf);
 233         }
 234
 235         if (file_exists(state_dir_path("strategy_opts", opts))) {
 236                 strbuf_reset(&buf);
 237                 if (read_one(state_dir_path("strategy_opts", opts), &buf))
 238                         return -1;
 239                 free(opts->strategy_opts);
 240                 opts->strategy_opts = xstrdup(buf.buf);
 241         }
 242
 243         strbuf_release(&buf);
 244
 245         return 0;
 246 }
 247
 248 static int write_basic_state(struct rebase_options *opts)
 249 {
 250         write_file(state_dir_path("head-name", opts), "%s",
 251                    opts->head_name ? opts->head_name : "detached HEAD");
 252         write_file(state_dir_path("onto", opts), "%s",
 253                    opts->onto ? oid_to_hex(&opts->onto->object.oid) : "");
 254         write_file(state_dir_path("orig-head", opts), "%s",
 255                    oid_to_hex(&opts->orig_head));
 256         write_file(state_dir_path("quiet", opts), "%s",
 257                    opts->flags & REBASE_NO_QUIET ? "" : "t");
 258         if (opts->flags & REBASE_VERBOSE)
 259                 write_file(state_dir_path("verbose", opts), "%s", "");
 260         if (opts->strategy)
 261                 write_file(state_dir_path("strategy", opts), "%s",
 262                            opts->strategy);
 263         if (opts->strategy_opts)
 264                 write_file(state_dir_path("strategy_opts", opts), "%s",
 265                            opts->strategy_opts);
 266         if (opts->allow_rerere_autoupdate >= 0)
 267                 write_file(state_dir_path("allow_rerere_autoupdate", opts),
 268                            "-%s-rerere-autoupdate",
 269                            opts->allow_rerere_autoupdate ? "" : "-no");
 270         if (opts->gpg_sign_opt)
 271                 write_file(state_dir_path("gpg_sign_opt", opts), "%s",
 272                            opts->gpg_sign_opt);
 273         if (opts->signoff)
 274                 write_file(state_dir_path("strategy", opts), "--signoff");
 275
 276         return 0;
 277 }
 278
 279 static int apply_autostash(struct rebase_options *opts)
 280 {
 281         const char *path = state_dir_path("autostash", opts);
 282         struct strbuf autostash = STRBUF_INIT;
 283         struct child_process stash_apply = CHILD_PROCESS_INIT;
 284
 285         if (!file_exists(path))
 286                 return 0;
 287
 288         if (read_one(path, &autostash))
 289                 return error(_("Could not read '%s'"), path);
 290         /* Ensure that the hash is not mistaken for a number */
 291         strbuf_addstr(&autostash, "^0");
 292         argv_array_pushl(&stash_apply.args,
 293                          "stash", "apply", autostash.buf, NULL);
 294         stash_apply.git_cmd = 1;
 295         stash_apply.no_stderr = stash_apply.no_stdout =
 296                 stash_apply.no_stdin = 1;
 297         if (!run_command(&stash_apply))
 298                 printf(_("Applied autostash.\n"));
 299         else {
 300                 struct argv_array args = ARGV_ARRAY_INIT;
 301                 int res = 0;
 302
 303                 argv_array_pushl(&args,
 304                                  "stash", "store", "-m", "autostash", "-q",
 305                                  autostash.buf, NULL);
 306                 if (run_command_v_opt(args.argv, RUN_GIT_CMD))
 307                         res = error(_("Cannot store %s"), autostash.buf);
 308                 argv_array_clear(&args);
 309                 strbuf_release(&autostash);
 310                 if (res)
 311                         return res;
 312
 313                 fprintf(stderr,
 314                         _("Applying autostash resulted in conflicts.\n"
 315                           "Your changes are safe in the stash.\n"
 316                           "You can run \"git stash pop\" or \"git stash drop\" "
 317                           "at any time.\n"));
 318         }
 319
 320         strbuf_release(&autostash);
 321         return 0;
 322 }
 323
 324 static int finish_rebase(struct rebase_options *opts)
 325 {
 326         struct strbuf dir = STRBUF_INIT;
 327         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 328
 329         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 330         apply_autostash(opts);
 331         close_all_packs(the_repository->objects);
 332         /*
 333          * We ignore errors in 'gc --auto', since the
 334          * user should see them.
 335          */
 336         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 337         strbuf_addstr(&dir, opts->state_dir);
 338         remove_dir_recursively(&dir, 0);
 339         strbuf_release(&dir);
 340
 341         return 0;
 342 }
 343
 344 static struct commit *peel_committish(const char *name)
 345 {
 346         struct object *obj;
 347         struct object_id oid;
 348
 349         if (get_oid(name, &oid))
 350                 return NULL;
 351         obj = parse_object(the_repository, &oid);
 352         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 353 }
 354
 355 static void add_var(struct strbuf *buf, const char *name, const char *value)
 356 {
 357         if (!value)
 358                 strbuf_addf(buf, "unset %s; ", name);
 359         else {
 360                 strbuf_addf(buf, "%s=", name);
 361                 sq_quote_buf(buf, value);
 362                 strbuf_addstr(buf, "; ");
 363         }
 364 }
 365
 366 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 367
 368 #define RESET_HEAD_DETACH (1<<0)
 369 #define RESET_HEAD_HARD (1<<1)
 370 #define RESET_HEAD_RUN_POST_CHECKOUT_HOOK (1<<2)
 371 #define RESET_HEAD_REFS_ONLY (1<<3)
 372
 373 static int reset_head(struct object_id *oid, const char *action,
 374                       const char *switch_to_branch, unsigned flags,
 375                       const char *reflog_orig_head, const char *reflog_head)
 376 {
 377         unsigned detach_head = flags & RESET_HEAD_DETACH;
 378         unsigned reset_hard = flags & RESET_HEAD_HARD;
 379         unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
 380         unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
 381         struct object_id head_oid;
 382         struct tree_desc desc[2] = { { NULL }, { NULL } };
 383         struct lock_file lock = LOCK_INIT;
 384         struct unpack_trees_options unpack_tree_opts;
 385         struct tree *tree;
 386         const char *reflog_action;
 387         struct strbuf msg = STRBUF_INIT;
 388         size_t prefix_len;
 389         struct object_id *orig = NULL, oid_orig,
 390                 *old_orig = NULL, oid_old_orig;
 391         int ret = 0, nr = 0;
 392
 393         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 394                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 395
 396         if (!refs_only && hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
 397                 ret = -1;
 398                 goto leave_reset_head;
 399         }
 400
 401         if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
 402                 ret = error(_("could not determine HEAD revision"));
 403                 goto leave_reset_head;
 404         }
 405
 406         if (!oid)
 407                 oid = &head_oid;
 408
 409         if (refs_only)
 410                 goto reset_head_refs;
 411
 412         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 413         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 414         unpack_tree_opts.head_idx = 1;
 415         unpack_tree_opts.src_index = the_repository->index;
 416         unpack_tree_opts.dst_index = the_repository->index;
 417         unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
 418         unpack_tree_opts.update = 1;
 419         unpack_tree_opts.merge = 1;
 420         if (!detach_head)
 421                 unpack_tree_opts.reset = 1;
 422
 423         if (repo_read_index_unmerged(the_repository) < 0) {
 424                 ret = error(_("could not read index"));
 425                 goto leave_reset_head;
 426         }
 427
 428         if (!reset_hard && !fill_tree_descriptor(&desc[nr++], &head_oid)) {
 429                 ret = error(_("failed to find tree of %s"),
 430                             oid_to_hex(&head_oid));
 431                 goto leave_reset_head;
 432         }
 433
 434         if (!fill_tree_descriptor(&desc[nr++], oid)) {
 435                 ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
 436                 goto leave_reset_head;
 437         }
 438
 439         if (unpack_trees(nr, desc, &unpack_tree_opts)) {
 440                 ret = -1;
 441                 goto leave_reset_head;
 442         }
 443
 444         tree = parse_tree_indirect(oid);
 445         prime_cache_tree(the_repository, the_repository->index, tree);
 446
 447         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
 448                 ret = error(_("could not write index"));
 449                 goto leave_reset_head;
 450         }
 451
 452 reset_head_refs:
 453         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 454         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 455         prefix_len = msg.len;
 456
 457         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 458                 old_orig = &oid_old_orig;
 459         if (!get_oid("HEAD", &oid_orig)) {
 460                 orig = &oid_orig;
 461                 if (!reflog_orig_head) {
 462                         strbuf_addstr(&msg, "updating ORIG_HEAD");
 463                         reflog_orig_head = msg.buf;
 464                 }
 465                 update_ref(reflog_orig_head, "ORIG_HEAD", orig, old_orig, 0,
 466                            UPDATE_REFS_MSG_ON_ERR);
 467         } else if (old_orig)
 468                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 469         if (!reflog_head) {
 470                 strbuf_setlen(&msg, prefix_len);
 471                 strbuf_addstr(&msg, "updating HEAD");
 472                 reflog_head = msg.buf;
 473         }
 474         if (!switch_to_branch)
 475                 ret = update_ref(reflog_head, "HEAD", oid, orig,
 476                                  detach_head ? REF_NO_DEREF : 0,
 477                                  UPDATE_REFS_MSG_ON_ERR);
 478         else {
 479                 ret = update_ref(reflog_orig_head, switch_to_branch, oid,
 480                                  NULL, 0, UPDATE_REFS_MSG_ON_ERR);
 481                 if (!ret)
 482                         ret = create_symref("HEAD", switch_to_branch,
 483                                             reflog_head);
 484         }
 485         if (run_hook)
 486                 run_hook_le(NULL, "post-checkout",
 487                             oid_to_hex(orig ? orig : &null_oid),
 488                             oid_to_hex(oid), "1", NULL);
 489
 490 leave_reset_head:
 491         strbuf_release(&msg);
 492         rollback_lock_file(&lock);
 493         while (nr)
 494                 free((void *)desc[--nr].buffer);
 495         return ret;
 496 }
 497
 498 static int move_to_original_branch(struct rebase_options *opts)
 499 {
 500         struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
 501         int ret;
 502
 503         if (!opts->head_name)
 504                 return 0; /* nothing to move back to */
 505
 506         if (!opts->onto)
 507                 BUG("move_to_original_branch without onto");
 508
 509         strbuf_addf(&orig_head_reflog, "rebase finished: %s onto %s",
 510                     opts->head_name, oid_to_hex(&opts->onto->object.oid));
 511         strbuf_addf(&head_reflog, "rebase finished: returning to %s",
 512                     opts->head_name);
 513         ret = reset_head(NULL, "", opts->head_name, RESET_HEAD_REFS_ONLY,
 514                          orig_head_reflog.buf, head_reflog.buf);
 515
 516         strbuf_release(&orig_head_reflog);
 517         strbuf_release(&head_reflog);
 518         return ret;
 519 }
 520
 521 static const char *resolvemsg =
 522 N_("Resolve all conflicts manually, mark them as resolved with\n"
 523 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 524 "You can instead skip this commit: run \"git rebase --skip\".\n"
 525 "To abort and get back to the state before \"git rebase\", run "
 526 "\"git rebase --abort\".");
 527
 528 static int run_am(struct rebase_options *opts)
 529 {
 530         struct child_process am = CHILD_PROCESS_INIT;
 531         struct child_process format_patch = CHILD_PROCESS_INIT;
 532         struct strbuf revisions = STRBUF_INIT;
 533         int status;
 534         char *rebased_patches;
 535
 536         am.git_cmd = 1;
 537         argv_array_push(&am.args, "am");
 538
 539         if (opts->action && !strcmp("continue", opts->action)) {
 540                 argv_array_push(&am.args, "--resolved");
 541                 argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 542                 if (opts->gpg_sign_opt)
 543                         argv_array_push(&am.args, opts->gpg_sign_opt);
 544                 status = run_command(&am);
 545                 if (status)
 546                         return status;
 547
 548                 return move_to_original_branch(opts);
 549         }
 550         if (opts->action && !strcmp("skip", opts->action)) {
 551                 argv_array_push(&am.args, "--skip");
 552                 argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 553                 status = run_command(&am);
 554                 if (status)
 555                         return status;
 556
 557                 return move_to_original_branch(opts);
 558         }
 559         if (opts->action && !strcmp("show-current-patch", opts->action)) {
 560                 argv_array_push(&am.args, "--show-current-patch");
 561                 return run_command(&am);
 562         }
 563
 564         strbuf_addf(&revisions, "%s...%s",
 565                     oid_to_hex(opts->root ?
 566                                /* this is now equivalent to !opts->upstream */
 567                                &opts->onto->object.oid :
 568                                &opts->upstream->object.oid),
 569                     oid_to_hex(&opts->orig_head));
 570
 571         rebased_patches = xstrdup(git_path("rebased-patches"));
 572         format_patch.out = open(rebased_patches,
 573                                 O_WRONLY | O_CREAT | O_TRUNC, 0666);
 574         if (format_patch.out < 0) {
 575                 status = error_errno(_("could not open '%s' for writing"),
 576                                      rebased_patches);
 577                 free(rebased_patches);
 578                 argv_array_clear(&am.args);
 579                 return status;
 580         }
 581
 582         format_patch.git_cmd = 1;
 583         argv_array_pushl(&format_patch.args, "format-patch", "-k", "--stdout",
 584                          "--full-index", "--cherry-pick", "--right-only",
 585                          "--src-prefix=a/", "--dst-prefix=b/", "--no-renames",
 586                          "--no-cover-letter", "--pretty=mboxrd", "--topo-order", NULL);
 587         if (opts->git_format_patch_opt.len)
 588                 argv_array_split(&format_patch.args,
 589                                  opts->git_format_patch_opt.buf);
 590         argv_array_push(&format_patch.args, revisions.buf);
 591         if (opts->restrict_revision)
 592                 argv_array_pushf(&format_patch.args, "^%s",
 593                                  oid_to_hex(&opts->restrict_revision->object.oid));
 594
 595         status = run_command(&format_patch);
 596         if (status) {
 597                 unlink(rebased_patches);
 598                 free(rebased_patches);
 599                 argv_array_clear(&am.args);
 600
 601                 reset_head(&opts->orig_head, "checkout", opts->head_name, 0,
 602                            "HEAD", NULL);
 603                 error(_("\ngit encountered an error while preparing the "
 604                         "patches to replay\n"
 605                         "these revisions:\n"
 606                         "\n    %s\n\n"
 607                         "As a result, git cannot rebase them."),
 608                       opts->revisions);
 609
 610                 strbuf_release(&revisions);
 611                 return status;
 612         }
 613         strbuf_release(&revisions);
 614
 615         am.in = open(rebased_patches, O_RDONLY);
 616         if (am.in < 0) {
 617                 status = error_errno(_("could not open '%s' for reading"),
 618                                      rebased_patches);
 619                 free(rebased_patches);
 620                 argv_array_clear(&am.args);
 621                 return status;
 622         }
 623
 624         argv_array_pushv(&am.args, opts->git_am_opts.argv);
 625         argv_array_push(&am.args, "--rebasing");
 626         argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 627         argv_array_push(&am.args, "--patch-format=mboxrd");
 628         if (opts->allow_rerere_autoupdate > 0)
 629                 argv_array_push(&am.args, "--rerere-autoupdate");
 630         else if (opts->allow_rerere_autoupdate == 0)
 631                 argv_array_push(&am.args, "--no-rerere-autoupdate");
 632         if (opts->gpg_sign_opt)
 633                 argv_array_push(&am.args, opts->gpg_sign_opt);
 634         status = run_command(&am);
 635         unlink(rebased_patches);
 636         free(rebased_patches);
 637
 638         if (!status) {
 639                 return move_to_original_branch(opts);
 640         }
 641
 642         if (is_directory(opts->state_dir))
 643                 write_basic_state(opts);
 644
 645         return status;
 646 }
 647
 648 static int run_specific_rebase(struct rebase_options *opts)
 649 {
 650         const char *argv[] = { NULL, NULL };
 651         struct strbuf script_snippet = STRBUF_INIT, buf = STRBUF_INIT;
 652         int status;
 653         const char *backend, *backend_func;
 654
 655         if (opts->type == REBASE_INTERACTIVE) {
 656                 /* Run builtin interactive rebase */
 657                 struct child_process child = CHILD_PROCESS_INIT;
 658
 659                 argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
 660                                  resolvemsg);
 661                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 662                         argv_array_push(&child.env_array,
 663                                         "GIT_SEQUENCE_EDITOR=:");
 664                         opts->autosquash = 0;
 665                 }
 666
 667                 child.git_cmd = 1;
 668                 argv_array_push(&child.args, "rebase--interactive");
 669
 670                 if (opts->action)
 671                         argv_array_pushf(&child.args, "--%s", opts->action);
 672                 if (opts->keep_empty)
 673                         argv_array_push(&child.args, "--keep-empty");
 674                 if (opts->rebase_merges)
 675                         argv_array_push(&child.args, "--rebase-merges");
 676                 if (opts->rebase_cousins)
 677                         argv_array_push(&child.args, "--rebase-cousins");
 678                 if (opts->autosquash)
 679                         argv_array_push(&child.args, "--autosquash");
 680                 if (opts->flags & REBASE_VERBOSE)
 681                         argv_array_push(&child.args, "--verbose");
 682                 if (opts->flags & REBASE_FORCE)
 683                         argv_array_push(&child.args, "--no-ff");
 684                 if (opts->restrict_revision)
 685                         argv_array_pushf(&child.args,
 686                                          "--restrict-revision=^%s",
 687                                          oid_to_hex(&opts->restrict_revision->object.oid));
 688                 if (opts->upstream)
 689                         argv_array_pushf(&child.args, "--upstream=%s",
 690                                          oid_to_hex(&opts->upstream->object.oid));
 691                 if (opts->onto)
 692                         argv_array_pushf(&child.args, "--onto=%s",
 693                                          oid_to_hex(&opts->onto->object.oid));
 694                 if (opts->squash_onto)
 695                         argv_array_pushf(&child.args, "--squash-onto=%s",
 696                                          oid_to_hex(opts->squash_onto));
 697                 if (opts->onto_name)
 698                         argv_array_pushf(&child.args, "--onto-name=%s",
 699                                          opts->onto_name);
 700                 argv_array_pushf(&child.args, "--head-name=%s",
 701                                  opts->head_name ?
 702                                  opts->head_name : "detached HEAD");
 703                 if (opts->strategy)
 704                         argv_array_pushf(&child.args, "--strategy=%s",
 705                                          opts->strategy);
 706                 if (opts->strategy_opts)
 707                         argv_array_pushf(&child.args, "--strategy-opts=%s",
 708                                          opts->strategy_opts);
 709                 if (opts->switch_to)
 710                         argv_array_pushf(&child.args, "--switch-to=%s",
 711                                          opts->switch_to);
 712                 if (opts->cmd)
 713                         argv_array_pushf(&child.args, "--cmd=%s", opts->cmd);
 714                 if (opts->allow_empty_message)
 715                         argv_array_push(&child.args, "--allow-empty-message");
 716                 if (opts->allow_rerere_autoupdate > 0)
 717                         argv_array_push(&child.args, "--rerere-autoupdate");
 718                 else if (opts->allow_rerere_autoupdate == 0)
 719                         argv_array_push(&child.args, "--no-rerere-autoupdate");
 720                 if (opts->gpg_sign_opt)
 721                         argv_array_push(&child.args, opts->gpg_sign_opt);
 722                 if (opts->signoff)
 723                         argv_array_push(&child.args, "--signoff");
 724                 if (opts->reschedule_failed_exec)
 725                         argv_array_push(&child.args, "--reschedule-failed-exec");
 726
 727                 status = run_command(&child);
 728                 goto finished_rebase;
 729         }
 730
 731         if (opts->type == REBASE_AM) {
 732                 status = run_am(opts);
 733                 goto finished_rebase;
 734         }
 735
 736         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 737         add_var(&script_snippet, "state_dir", opts->state_dir);
 738
 739         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 740         add_var(&script_snippet, "upstream", opts->upstream ?
 741                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 742         add_var(&script_snippet, "head_name",
 743                 opts->head_name ? opts->head_name : "detached HEAD");
 744         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 745         add_var(&script_snippet, "onto", opts->onto ?
 746                 oid_to_hex(&opts->onto->object.oid) : NULL);
 747         add_var(&script_snippet, "onto_name", opts->onto_name);
 748         add_var(&script_snippet, "revisions", opts->revisions);
 749         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 750                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 751         add_var(&script_snippet, "GIT_QUIET",
 752                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 753         sq_quote_argv_pretty(&buf, opts->git_am_opts.argv);
 754         add_var(&script_snippet, "git_am_opt", buf.buf);
 755         strbuf_release(&buf);
 756         add_var(&script_snippet, "verbose",
 757                 opts->flags & REBASE_VERBOSE ? "t" : "");
 758         add_var(&script_snippet, "diffstat",
 759                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 760         add_var(&script_snippet, "force_rebase",
 761                 opts->flags & REBASE_FORCE ? "t" : "");
 762         if (opts->switch_to)
 763                 add_var(&script_snippet, "switch_to", opts->switch_to);
 764         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 765         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 766         add_var(&script_snippet, "allow_rerere_autoupdate",
 767                 opts->allow_rerere_autoupdate < 0 ? "" :
 768                 opts->allow_rerere_autoupdate ?
 769                 "--rerere-autoupdate" : "--no-rerere-autoupdate");
 770         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 771         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 772         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 773         add_var(&script_snippet, "cmd", opts->cmd);
 774         add_var(&script_snippet, "allow_empty_message",
 775                 opts->allow_empty_message ?  "--allow-empty-message" : "");
 776         add_var(&script_snippet, "rebase_merges",
 777                 opts->rebase_merges ? "t" : "");
 778         add_var(&script_snippet, "rebase_cousins",
 779                 opts->rebase_cousins ? "t" : "");
 780         add_var(&script_snippet, "strategy", opts->strategy);
 781         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
 782         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
 783         add_var(&script_snippet, "squash_onto",
 784                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
 785         add_var(&script_snippet, "git_format_patch_opt",
 786                 opts->git_format_patch_opt.buf);
 787
 788         if (is_interactive(opts) &&
 789             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 790                 strbuf_addstr(&script_snippet,
 791                               "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
 792                 opts->autosquash = 0;
 793         }
 794
 795         switch (opts->type) {
 796         case REBASE_AM:
 797                 backend = "git-rebase--am";
 798                 backend_func = "git_rebase__am";
 799                 break;
 800         case REBASE_PRESERVE_MERGES:
 801                 backend = "git-rebase--preserve-merges";
 802                 backend_func = "git_rebase__preserve_merges";
 803                 break;
 804         default:
 805                 BUG("Unhandled rebase type %d", opts->type);
 806                 break;
 807         }
 808
 809         strbuf_addf(&script_snippet,
 810                     ". git-sh-setup && . git-rebase--common &&"
 811                     " . %s && %s", backend, backend_func);
 812         argv[0] = script_snippet.buf;
 813
 814         status = run_command_v_opt(argv, RUN_USING_SHELL);
 815 finished_rebase:
 816         if (opts->dont_finish_rebase)
 817                 ; /* do nothing */
 818         else if (opts->type == REBASE_INTERACTIVE)
 819                 ; /* interactive rebase cleans up after itself */
 820         else if (status == 0) {
 821                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 822                         finish_rebase(opts);
 823         } else if (status == 2) {
 824                 struct strbuf dir = STRBUF_INIT;
 825
 826                 apply_autostash(opts);
 827                 strbuf_addstr(&dir, opts->state_dir);
 828                 remove_dir_recursively(&dir, 0);
 829                 strbuf_release(&dir);
 830                 die("Nothing to do");
 831         }
 832
 833         strbuf_release(&script_snippet);
 834
 835         return status ? -1 : 0;
 836 }
 837
 838 static int rebase_config(const char *var, const char *value, void *data)
 839 {
 840         struct rebase_options *opts = data;
 841
 842         if (!strcmp(var, "rebase.stat")) {
 843                 if (git_config_bool(var, value))
 844                         opts->flags |= REBASE_DIFFSTAT;
 845                 else
 846                         opts->flags &= !REBASE_DIFFSTAT;
 847                 return 0;
 848         }
 849
 850         if (!strcmp(var, "rebase.autosquash")) {
 851                 opts->autosquash = git_config_bool(var, value);
 852                 return 0;
 853         }
 854
 855         if (!strcmp(var, "commit.gpgsign")) {
 856                 free(opts->gpg_sign_opt);
 857                 opts->gpg_sign_opt = git_config_bool(var, value) ?
 858                         xstrdup("-S") : NULL;
 859                 return 0;
 860         }
 861
 862         if (!strcmp(var, "rebase.autostash")) {
 863                 opts->autostash = git_config_bool(var, value);
 864                 return 0;
 865         }
 866
 867         if (!strcmp(var, "rebase.reschedulefailedexec")) {
 868                 opts->reschedule_failed_exec = git_config_bool(var, value);
 869                 return 0;
 870         }
 871
 872         return git_default_config(var, value, data);
 873 }
 874
 875 /*
 876  * Determines whether the commits in from..to are linear, i.e. contain
 877  * no merge commits. This function *expects* `from` to be an ancestor of
 878  * `to`.
 879  */
 880 static int is_linear_history(struct commit *from, struct commit *to)
 881 {
 882         while (to && to != from) {
 883                 parse_commit(to);
 884                 if (!to->parents)
 885                         return 1;
 886                 if (to->parents->next)
 887                         return 0;
 888                 to = to->parents->item;
 889         }
 890         return 1;
 891 }
 892
 893 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 894                             struct object_id *merge_base)
 895 {
 896         struct commit *head = lookup_commit(the_repository, head_oid);
 897         struct commit_list *merge_bases;
 898         int res;
 899
 900         if (!head)
 901                 return 0;
 902
 903         merge_bases = get_merge_bases(onto, head);
 904         if (merge_bases && !merge_bases->next) {
 905                 oidcpy(merge_base, &merge_bases->item->object.oid);
 906                 res = oideq(merge_base, &onto->object.oid);
 907         } else {
 908                 oidcpy(merge_base, &null_oid);
 909                 res = 0;
 910         }
 911         free_commit_list(merge_bases);
 912         return res && is_linear_history(onto, head);
 913 }
 914
 915 /* -i followed by -m is still -i */
 916 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 917 {
 918         struct rebase_options *opts = opt->value;
 919
 920         BUG_ON_OPT_NEG(unset);
 921         BUG_ON_OPT_ARG(arg);
 922
 923         if (!is_interactive(opts))
 924                 opts->type = REBASE_MERGE;
 925
 926         return 0;
 927 }
 928
 929 /* -i followed by -p is still explicitly interactive, but -p alone is not */
 930 static int parse_opt_interactive(const struct option *opt, const char *arg,
 931                                  int unset)
 932 {
 933         struct rebase_options *opts = opt->value;
 934
 935         BUG_ON_OPT_NEG(unset);
 936         BUG_ON_OPT_ARG(arg);
 937
 938         opts->type = REBASE_INTERACTIVE;
 939         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 940
 941         return 0;
 942 }
 943
 944 static void NORETURN error_on_missing_default_upstream(void)
 945 {
 946         struct branch *current_branch = branch_get(NULL);
 947
 948         printf(_("%s\n"
 949                  "Please specify which branch you want to rebase against.\n"
 950                  "See git-rebase(1) for details.\n"
 951                  "\n"
 952                  "    git rebase '<branch>'\n"
 953                  "\n"),
 954                 current_branch ? _("There is no tracking information for "
 955                         "the current branch.") :
 956                         _("You are not currently on a branch."));
 957
 958         if (current_branch) {
 959                 const char *remote = current_branch->remote_name;
 960
 961                 if (!remote)
 962                         remote = _("<remote>");
 963
 964                 printf(_("If you wish to set tracking information for this "
 965                          "branch you can do so with:\n"
 966                          "\n"
 967                          "    git branch --set-upstream-to=%s/<branch> %s\n"
 968                          "\n"),
 969                        remote, current_branch->name);
 970         }
 971         exit(1);
 972 }
 973
 974 static void set_reflog_action(struct rebase_options *options)
 975 {
 976         const char *env;
 977         struct strbuf buf = STRBUF_INIT;
 978
 979         if (!is_interactive(options))
 980                 return;
 981
 982         env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 983         if (env && strcmp("rebase", env))
 984                 return; /* only override it if it is "rebase" */
 985
 986         strbuf_addf(&buf, "rebase -i (%s)", options->action);
 987         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, buf.buf, 1);
 988         strbuf_release(&buf);
 989 }
 990
 991 static int check_exec_cmd(const char *cmd)
 992 {
 993         if (strchr(cmd, '\n'))
 994                 return error(_("exec commands cannot contain newlines"));
 995
 996         /* Does the command consist purely of whitespace? */
 997         if (!cmd[strspn(cmd, " \t\r\f\v")])
 998                 return error(_("empty exec command"));
 999
1000         return 0;
1001 }
1002
1003
1004 int cmd_rebase(int argc, const char **argv, const char *prefix)
1005 {
1006         struct rebase_options options = {
1007                 .type = REBASE_UNSPECIFIED,
1008                 .flags = REBASE_NO_QUIET,
1009                 .git_am_opts = ARGV_ARRAY_INIT,
1010                 .allow_rerere_autoupdate  = -1,
1011                 .allow_empty_message = 1,
1012                 .git_format_patch_opt = STRBUF_INIT,
1013         };
1014         const char *branch_name;
1015         int ret, flags, total_argc, in_progress = 0;
1016         int ok_to_skip_pre_rebase = 0;
1017         struct strbuf msg = STRBUF_INIT;
1018         struct strbuf revisions = STRBUF_INIT;
1019         struct strbuf buf = STRBUF_INIT;
1020         struct object_id merge_base;
1021         enum {
1022                 NO_ACTION,
1023                 ACTION_CONTINUE,
1024                 ACTION_SKIP,
1025                 ACTION_ABORT,
1026                 ACTION_QUIT,
1027                 ACTION_EDIT_TODO,
1028                 ACTION_SHOW_CURRENT_PATCH,
1029         } action = NO_ACTION;
1030         const char *gpg_sign = NULL;
1031         struct string_list exec = STRING_LIST_INIT_NODUP;
1032         const char *rebase_merges = NULL;
1033         int fork_point = -1;
1034         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
1035         struct object_id squash_onto;
1036         char *squash_onto_name = NULL;
1037         struct option builtin_rebase_options[] = {
1038                 OPT_STRING(0, "onto", &options.onto_name,
1039                            N_("revision"),
1040                            N_("rebase onto given branch instead of upstream")),
1041                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
1042                          N_("allow pre-rebase hook to run")),
1043                 OPT_NEGBIT('q', "quiet", &options.flags,
1044                            N_("be quiet. implies --no-stat"),
1045                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
1046                 OPT_BIT('v', "verbose", &options.flags,
1047                         N_("display a diffstat of what changed upstream"),
1048                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
1049                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
1050                         N_("do not show diffstat of what changed upstream"),
1051                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
1052                 OPT_BOOL(0, "signoff", &options.signoff,
1053                          N_("add a Signed-off-by: line to each commit")),
1054                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &options.git_am_opts,
1055                                   NULL, N_("passed to 'git am'"),
1056                                   PARSE_OPT_NOARG),
1057                 OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
1058                                   &options.git_am_opts, NULL,
1059                                   N_("passed to 'git am'"), PARSE_OPT_NOARG),
1060                 OPT_PASSTHRU_ARGV(0, "ignore-date", &options.git_am_opts, NULL,
1061                                   N_("passed to 'git am'"), PARSE_OPT_NOARG),
1062                 OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
1063                                   N_("passed to 'git apply'"), 0),
1064                 OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
1065                                   N_("action"), N_("passed to 'git apply'"), 0),
1066                 OPT_BIT('f', "force-rebase", &options.flags,
1067                         N_("cherry-pick all commits, even if unchanged"),
1068                         REBASE_FORCE),
1069                 OPT_BIT(0, "no-ff", &options.flags,
1070                         N_("cherry-pick all commits, even if unchanged"),
1071                         REBASE_FORCE),
1072                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
1073                             ACTION_CONTINUE),
1074                 OPT_CMDMODE(0, "skip", &action,
1075                             N_("skip current patch and continue"), ACTION_SKIP),
1076                 OPT_CMDMODE(0, "abort", &action,
1077                             N_("abort and check out the original branch"),
1078                             ACTION_ABORT),
1079                 OPT_CMDMODE(0, "quit", &action,
1080                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
1081                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
1082                             "during an interactive rebase"), ACTION_EDIT_TODO),
1083                 OPT_CMDMODE(0, "show-current-patch", &action,
1084                             N_("show the patch file being applied or merged"),
1085                             ACTION_SHOW_CURRENT_PATCH),
1086                 { OPTION_CALLBACK, 'm', "merge", &options, NULL,
1087                         N_("use merging strategies to rebase"),
1088                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1089                         parse_opt_merge },
1090                 { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
1091                         N_("let the user edit the list of commits to rebase"),
1092                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1093                         parse_opt_interactive },
1094                 OPT_SET_INT('p', "preserve-merges", &options.type,
1095                             N_("try to recreate merges instead of ignoring "
1096                                "them"), REBASE_PRESERVE_MERGES),
1097                 OPT_BOOL(0, "rerere-autoupdate",
1098                          &options.allow_rerere_autoupdate,
1099                          N_("allow rerere to update index with resolved "
1100                             "conflict")),
1101                 OPT_BOOL('k', "keep-empty", &options.keep_empty,
1102                          N_("preserve empty commits during rebase")),
1103                 OPT_BOOL(0, "autosquash", &options.autosquash,
1104                          N_("move commits that begin with "
1105                             "squash!/fixup! under -i")),
1106                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
1107                         N_("GPG-sign commits"),
1108                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
1109                 OPT_BOOL(0, "autostash", &options.autostash,
1110                          N_("automatically stash/stash pop before and after")),
1111                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
1112                                 N_("add exec lines after each commit of the "
1113                                    "editable list")),
1114                 OPT_BOOL(0, "allow-empty-message",
1115                          &options.allow_empty_message,
1116                          N_("allow rebasing commits with empty messages")),
1117                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
1118                         N_("mode"),
1119                         N_("try to rebase merges instead of skipping them"),
1120                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
1121                 OPT_BOOL(0, "fork-point", &fork_point,
1122                          N_("use 'merge-base --fork-point' to refine upstream")),
1123                 OPT_STRING('s', "strategy", &options.strategy,
1124                            N_("strategy"), N_("use the given merge strategy")),
1125                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
1126                                 N_("option"),
1127                                 N_("pass the argument through to the merge "
1128                                    "strategy")),
1129                 OPT_BOOL(0, "root", &options.root,
1130                          N_("rebase all reachable commits up to the root(s)")),
1131                 OPT_BOOL(0, "reschedule-failed-exec",
1132                          &options.reschedule_failed_exec,
1133                          N_("automatically re-schedule any `exec` that fails")),
1134                 OPT_END(),
1135         };
1136         int i;
1137
1138         /*
1139          * NEEDSWORK: Once the builtin rebase has been tested enough
1140          * and git-legacy-rebase.sh is retired to contrib/, this preamble
1141          * can be removed.
1142          */
1143
1144         if (!use_builtin_rebase()) {
1145                 const char *path = mkpath("%s/git-legacy-rebase",
1146                                           git_exec_path());
1147
1148                 if (sane_execvp(path, (char **)argv) < 0)
1149                         die_errno(_("could not exec %s"), path);
1150                 else
1151                         BUG("sane_execvp() returned???");
1152         }
1153
1154         if (argc == 2 && !strcmp(argv[1], "-h"))
1155                 usage_with_options(builtin_rebase_usage,
1156                                    builtin_rebase_options);
1157
1158         prefix = setup_git_directory();
1159         trace_repo_setup(prefix);
1160         setup_work_tree();
1161
1162         git_config(rebase_config, &options);
1163
1164         strbuf_reset(&buf);
1165         strbuf_addf(&buf, "%s/applying", apply_dir());
1166         if(file_exists(buf.buf))
1167                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
1168
1169         if (is_directory(apply_dir())) {
1170                 options.type = REBASE_AM;
1171                 options.state_dir = apply_dir();
1172         } else if (is_directory(merge_dir())) {
1173                 strbuf_reset(&buf);
1174                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
1175                 if (is_directory(buf.buf)) {
1176                         options.type = REBASE_PRESERVE_MERGES;
1177                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1178                 } else {
1179                         strbuf_reset(&buf);
1180                         strbuf_addf(&buf, "%s/interactive", merge_dir());
1181                         if(file_exists(buf.buf)) {
1182                                 options.type = REBASE_INTERACTIVE;
1183                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1184                         } else
1185                                 options.type = REBASE_MERGE;
1186                 }
1187                 options.state_dir = merge_dir();
1188         }
1189
1190         if (options.type != REBASE_UNSPECIFIED)
1191                 in_progress = 1;
1192
1193         total_argc = argc;
1194         argc = parse_options(argc, argv, prefix,
1195                              builtin_rebase_options,
1196                              builtin_rebase_usage, 0);
1197
1198         if (action != NO_ACTION && total_argc != 2) {
1199                 usage_with_options(builtin_rebase_usage,
1200                                    builtin_rebase_options);
1201         }
1202
1203         if (argc > 2)
1204                 usage_with_options(builtin_rebase_usage,
1205                                    builtin_rebase_options);
1206
1207         if (action != NO_ACTION && !in_progress)
1208                 die(_("No rebase in progress?"));
1209         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
1210
1211         if (action == ACTION_EDIT_TODO && !is_interactive(&options))
1212                 die(_("The --edit-todo action can only be used during "
1213                       "interactive rebase."));
1214
1215         switch (action) {
1216         case ACTION_CONTINUE: {
1217                 struct object_id head;
1218                 struct lock_file lock_file = LOCK_INIT;
1219                 int fd;
1220
1221                 options.action = "continue";
1222                 set_reflog_action(&options);
1223
1224                 /* Sanity check */
1225                 if (get_oid("HEAD", &head))
1226                         die(_("Cannot read HEAD"));
1227
1228                 fd = hold_locked_index(&lock_file, 0);
1229                 if (repo_read_index(the_repository) < 0)
1230                         die(_("could not read index"));
1231                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
1232                               NULL);
1233                 if (0 <= fd)
1234                         repo_update_index_if_able(the_repository, &lock_file);
1235                 rollback_lock_file(&lock_file);
1236
1237                 if (has_unstaged_changes(the_repository, 1)) {
1238                         puts(_("You must edit all merge conflicts and then\n"
1239                                "mark them as resolved using git add"));
1240                         exit(1);
1241                 }
1242                 if (read_basic_state(&options))
1243                         exit(1);
1244                 goto run_rebase;
1245         }
1246         case ACTION_SKIP: {
1247                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1248
1249                 options.action = "skip";
1250                 set_reflog_action(&options);
1251
1252                 rerere_clear(the_repository, &merge_rr);
1253                 string_list_clear(&merge_rr, 1);
1254
1255                 if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
1256                                NULL, NULL) < 0)
1257                         die(_("could not discard worktree changes"));
1258                 remove_branch_state(the_repository);
1259                 if (read_basic_state(&options))
1260                         exit(1);
1261                 goto run_rebase;
1262         }
1263         case ACTION_ABORT: {
1264                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1265                 options.action = "abort";
1266                 set_reflog_action(&options);
1267
1268                 rerere_clear(the_repository, &merge_rr);
1269                 string_list_clear(&merge_rr, 1);
1270
1271                 if (read_basic_state(&options))
1272                         exit(1);
1273                 if (reset_head(&options.orig_head, "reset",
1274                                options.head_name, RESET_HEAD_HARD,
1275                                NULL, NULL) < 0)
1276                         die(_("could not move back to %s"),
1277                             oid_to_hex(&options.orig_head));
1278                 remove_branch_state(the_repository);
1279                 ret = finish_rebase(&options);
1280                 goto cleanup;
1281         }
1282         case ACTION_QUIT: {
1283                 strbuf_reset(&buf);
1284                 strbuf_addstr(&buf, options.state_dir);
1285                 ret = !!remove_dir_recursively(&buf, 0);
1286                 if (ret)
1287                         die(_("could not remove '%s'"), options.state_dir);
1288                 goto cleanup;
1289         }
1290         case ACTION_EDIT_TODO:
1291                 options.action = "edit-todo";
1292                 options.dont_finish_rebase = 1;
1293                 goto run_rebase;
1294         case ACTION_SHOW_CURRENT_PATCH:
1295                 options.action = "show-current-patch";
1296                 options.dont_finish_rebase = 1;
1297                 goto run_rebase;
1298         case NO_ACTION:
1299                 break;
1300         default:
1301                 BUG("action: %d", action);
1302         }
1303
1304         /* Make sure no rebase is in progress */
1305         if (in_progress) {
1306                 const char *last_slash = strrchr(options.state_dir, '/');
1307                 const char *state_dir_base =
1308                         last_slash ? last_slash + 1 : options.state_dir;
1309                 const char *cmd_live_rebase =
1310                         "git rebase (--continue | --abort | --skip)";
1311                 strbuf_reset(&buf);
1312                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1313                 die(_("It seems that there is already a %s directory, and\n"
1314                       "I wonder if you are in the middle of another rebase.  "
1315                       "If that is the\n"
1316                       "case, please try\n\t%s\n"
1317                       "If that is not the case, please\n\t%s\n"
1318                       "and run me again.  I am stopping in case you still "
1319                       "have something\n"
1320                       "valuable there.\n"),
1321                     state_dir_base, cmd_live_rebase, buf.buf);
1322         }
1323
1324         for (i = 0; i < options.git_am_opts.argc; i++) {
1325                 const char *option = options.git_am_opts.argv[i], *p;
1326                 if (!strcmp(option, "--committer-date-is-author-date") ||
1327                     !strcmp(option, "--ignore-date") ||
1328                     !strcmp(option, "--whitespace=fix") ||
1329                     !strcmp(option, "--whitespace=strip"))
1330                         options.flags |= REBASE_FORCE;
1331                 else if (skip_prefix(option, "-C", &p)) {
1332                         while (*p)
1333                                 if (!isdigit(*(p++)))
1334                                         die(_("switch `C' expects a "
1335                                               "numerical value"));
1336                 } else if (skip_prefix(option, "--whitespace=", &p)) {
1337                         if (*p && strcmp(p, "warn") && strcmp(p, "nowarn") &&
1338                             strcmp(p, "error") && strcmp(p, "error-all"))
1339                                 die("Invalid whitespace option: '%s'", p);
1340                 }
1341         }
1342
1343         for (i = 0; i < exec.nr; i++)
1344                 if (check_exec_cmd(exec.items[i].string))
1345                         exit(1);
1346
1347         if (!(options.flags & REBASE_NO_QUIET))
1348                 argv_array_push(&options.git_am_opts, "-q");
1349
1350         if (options.keep_empty)
1351                 imply_interactive(&options, "--keep-empty");
1352
1353         if (gpg_sign) {
1354                 free(options.gpg_sign_opt);
1355                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1356         }
1357
1358         if (exec.nr) {
1359                 int i;
1360
1361                 imply_interactive(&options, "--exec");
1362
1363                 strbuf_reset(&buf);
1364                 for (i = 0; i < exec.nr; i++)
1365                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1366                 options.cmd = xstrdup(buf.buf);
1367         }
1368
1369         if (rebase_merges) {
1370                 if (!*rebase_merges)
1371                         ; /* default mode; do nothing */
1372                 else if (!strcmp("rebase-cousins", rebase_merges))
1373                         options.rebase_cousins = 1;
1374                 else if (strcmp("no-rebase-cousins", rebase_merges))
1375                         die(_("Unknown mode: %s"), rebase_merges);
1376                 options.rebase_merges = 1;
1377                 imply_interactive(&options, "--rebase-merges");
1378         }
1379
1380         if (strategy_options.nr) {
1381                 int i;
1382
1383                 if (!options.strategy)
1384                         options.strategy = "recursive";
1385
1386                 strbuf_reset(&buf);
1387                 for (i = 0; i < strategy_options.nr; i++)
1388                         strbuf_addf(&buf, " --%s",
1389                                     strategy_options.items[i].string);
1390                 options.strategy_opts = xstrdup(buf.buf);
1391         }
1392
1393         if (options.strategy) {
1394                 options.strategy = xstrdup(options.strategy);
1395                 switch (options.type) {
1396                 case REBASE_AM:
1397                         die(_("--strategy requires --merge or --interactive"));
1398                 case REBASE_MERGE:
1399                 case REBASE_INTERACTIVE:
1400                 case REBASE_PRESERVE_MERGES:
1401                         /* compatible */
1402                         break;
1403                 case REBASE_UNSPECIFIED:
1404                         options.type = REBASE_MERGE;
1405                         break;
1406                 default:
1407                         BUG("unhandled rebase type (%d)", options.type);
1408                 }
1409         }
1410
1411         if (options.type == REBASE_MERGE)
1412                 imply_interactive(&options, "--merge");
1413
1414         if (options.root && !options.onto_name)
1415                 imply_interactive(&options, "--root without --onto");
1416
1417         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1418                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1419
1420         switch (options.type) {
1421         case REBASE_MERGE:
1422         case REBASE_INTERACTIVE:
1423         case REBASE_PRESERVE_MERGES:
1424                 options.state_dir = merge_dir();
1425                 break;
1426         case REBASE_AM:
1427                 options.state_dir = apply_dir();
1428                 break;
1429         default:
1430                 /* the default rebase backend is `--am` */
1431                 options.type = REBASE_AM;
1432                 options.state_dir = apply_dir();
1433                 break;
1434         }
1435
1436         if (options.reschedule_failed_exec && !is_interactive(&options))
1437                 die(_("%s requires an interactive rebase"), "--reschedule-failed-exec");
1438
1439         if (options.git_am_opts.argc) {
1440                 /* all am options except -q are compatible only with --am */
1441                 for (i = options.git_am_opts.argc - 1; i >= 0; i--)
1442                         if (strcmp(options.git_am_opts.argv[i], "-q"))
1443                                 break;
1444
1445                 if (is_interactive(&options) && i >= 0)
1446                         die(_("cannot combine am options with either "
1447                               "interactive or merge options"));
1448         }
1449
1450         if (options.signoff) {
1451                 if (options.type == REBASE_PRESERVE_MERGES)
1452                         die("cannot combine '--signoff' with "
1453                             "'--preserve-merges'");
1454                 argv_array_push(&options.git_am_opts, "--signoff");
1455                 options.flags |= REBASE_FORCE;
1456         }
1457
1458         if (options.type == REBASE_PRESERVE_MERGES) {
1459                 /*
1460                  * Note: incompatibility with --signoff handled in signoff block above
1461                  * Note: incompatibility with --interactive is just a strong warning;
1462                  *       git-rebase.txt caveats with "unless you know what you are doing"
1463                  */
1464                 if (options.rebase_merges)
1465                         die(_("cannot combine '--preserve-merges' with "
1466                               "'--rebase-merges'"));
1467
1468                 if (options.reschedule_failed_exec)
1469                         die(_("error: cannot combine '--preserve-merges' with "
1470                               "'--reschedule-failed-exec'"));
1471         }
1472
1473         if (options.rebase_merges) {
1474                 if (strategy_options.nr)
1475                         die(_("cannot combine '--rebase-merges' with "
1476                               "'--strategy-option'"));
1477                 if (options.strategy)
1478                         die(_("cannot combine '--rebase-merges' with "
1479                               "'--strategy'"));
1480         }
1481
1482         if (!options.root) {
1483                 if (argc < 1) {
1484                         struct branch *branch;
1485
1486                         branch = branch_get(NULL);
1487                         options.upstream_name = branch_get_upstream(branch,
1488                                                                     NULL);
1489                         if (!options.upstream_name)
1490                                 error_on_missing_default_upstream();
1491                         if (fork_point < 0)
1492                                 fork_point = 1;
1493                 } else {
1494                         options.upstream_name = argv[0];
1495                         argc--;
1496                         argv++;
1497                         if (!strcmp(options.upstream_name, "-"))
1498                                 options.upstream_name = "@{-1}";
1499                 }
1500                 options.upstream = peel_committish(options.upstream_name);
1501                 if (!options.upstream)
1502                         die(_("invalid upstream '%s'"), options.upstream_name);
1503                 options.upstream_arg = options.upstream_name;
1504         } else {
1505                 if (!options.onto_name) {
1506                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1507                                         &squash_onto, NULL, NULL) < 0)
1508                                 die(_("Could not create new root commit"));
1509                         options.squash_onto = &squash_onto;
1510                         options.onto_name = squash_onto_name =
1511                                 xstrdup(oid_to_hex(&squash_onto));
1512                 }
1513                 options.upstream_name = NULL;
1514                 options.upstream = NULL;
1515                 if (argc > 1)
1516                         usage_with_options(builtin_rebase_usage,
1517                                            builtin_rebase_options);
1518                 options.upstream_arg = "--root";
1519         }
1520
1521         /* Make sure the branch to rebase onto is valid. */
1522         if (!options.onto_name)
1523                 options.onto_name = options.upstream_name;
1524         if (strstr(options.onto_name, "...")) {
1525                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
1526                         die(_("'%s': need exactly one merge base"),
1527                             options.onto_name);
1528                 options.onto = lookup_commit_or_die(&merge_base,
1529                                                     options.onto_name);
1530         } else {
1531                 options.onto = peel_committish(options.onto_name);
1532                 if (!options.onto)
1533                         die(_("Does not point to a valid commit '%s'"),
1534                                 options.onto_name);
1535         }
1536
1537         /*
1538          * If the branch to rebase is given, that is the branch we will rebase
1539          * branch_name -- branch/commit being rebased, or
1540          *                HEAD (already detached)
1541          * orig_head -- commit object name of tip of the branch before rebasing
1542          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1543          */
1544         if (argc == 1) {
1545                 /* Is it "rebase other branchname" or "rebase other commit"? */
1546                 branch_name = argv[0];
1547                 options.switch_to = argv[0];
1548
1549                 /* Is it a local branch? */
1550                 strbuf_reset(&buf);
1551                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1552                 if (!read_ref(buf.buf, &options.orig_head))
1553                         options.head_name = xstrdup(buf.buf);
1554                 /* If not is it a valid ref (branch or commit)? */
1555                 else if (!get_oid(branch_name, &options.orig_head))
1556                         options.head_name = NULL;
1557                 else
1558                         die(_("fatal: no such branch/commit '%s'"),
1559                             branch_name);
1560         } else if (argc == 0) {
1561                 /* Do not need to switch branches, we are already on it. */
1562                 options.head_name =
1563                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1564                                          &flags));
1565                 if (!options.head_name)
1566                         die(_("No such ref: %s"), "HEAD");
1567                 if (flags & REF_ISSYMREF) {
1568                         if (!skip_prefix(options.head_name,
1569                                          "refs/heads/", &branch_name))
1570                                 branch_name = options.head_name;
1571
1572                 } else {
1573                         free(options.head_name);
1574                         options.head_name = NULL;
1575                         branch_name = "HEAD";
1576                 }
1577                 if (get_oid("HEAD", &options.orig_head))
1578                         die(_("Could not resolve HEAD to a revision"));
1579         } else
1580                 BUG("unexpected number of arguments left to parse");
1581
1582         if (fork_point > 0) {
1583                 struct commit *head =
1584                         lookup_commit_reference(the_repository,
1585                                                 &options.orig_head);
1586                 options.restrict_revision =
1587                         get_fork_point(options.upstream_name, head);
1588         }
1589
1590         if (repo_read_index(the_repository) < 0)
1591                 die(_("could not read index"));
1592
1593         if (options.autostash) {
1594                 struct lock_file lock_file = LOCK_INIT;
1595                 int fd;
1596
1597                 fd = hold_locked_index(&lock_file, 0);
1598                 refresh_cache(REFRESH_QUIET);
1599                 if (0 <= fd)
1600                         repo_update_index_if_able(the_repository, &lock_file);
1601                 rollback_lock_file(&lock_file);
1602
1603                 if (has_unstaged_changes(the_repository, 1) ||
1604                     has_uncommitted_changes(the_repository, 1)) {
1605                         const char *autostash =
1606                                 state_dir_path("autostash", &options);
1607                         struct child_process stash = CHILD_PROCESS_INIT;
1608                         struct object_id oid;
1609                         struct commit *head =
1610                                 lookup_commit_reference(the_repository,
1611                                                         &options.orig_head);
1612
1613                         argv_array_pushl(&stash.args,
1614                                          "stash", "create", "autostash", NULL);
1615                         stash.git_cmd = 1;
1616                         stash.no_stdin = 1;
1617                         strbuf_reset(&buf);
1618                         if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
1619                                 die(_("Cannot autostash"));
1620                         strbuf_trim_trailing_newline(&buf);
1621                         if (get_oid(buf.buf, &oid))
1622                                 die(_("Unexpected stash response: '%s'"),
1623                                     buf.buf);
1624                         strbuf_reset(&buf);
1625                         strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
1626
1627                         if (safe_create_leading_directories_const(autostash))
1628                                 die(_("Could not create directory for '%s'"),
1629                                     options.state_dir);
1630                         write_file(autostash, "%s", oid_to_hex(&oid));
1631                         printf(_("Created autostash: %s\n"), buf.buf);
1632                         if (reset_head(&head->object.oid, "reset --hard",
1633                                        NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
1634                                 die(_("could not reset --hard"));
1635                         printf(_("HEAD is now at %s"),
1636                                find_unique_abbrev(&head->object.oid,
1637                                                   DEFAULT_ABBREV));
1638                         strbuf_reset(&buf);
1639                         pp_commit_easy(CMIT_FMT_ONELINE, head, &buf);
1640                         if (buf.len > 0)
1641                                 printf(" %s", buf.buf);
1642                         putchar('\n');
1643
1644                         if (discard_index(the_repository->index) < 0 ||
1645                                 repo_read_index(the_repository) < 0)
1646                                 die(_("could not read index"));
1647                 }
1648         }
1649
1650         if (require_clean_work_tree(the_repository, "rebase",
1651                                     _("Please commit or stash them."), 1, 1)) {
1652                 ret = 1;
1653                 goto cleanup;
1654         }
1655
1656         /*
1657          * Now we are rebasing commits upstream..orig_head (or with --root,
1658          * everything leading up to orig_head) on top of onto.
1659          */
1660
1661         /*
1662          * Check if we are already based on onto with linear history,
1663          * but this should be done only when upstream and onto are the same
1664          * and if this is not an interactive rebase.
1665          */
1666         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
1667             !is_interactive(&options) && !options.restrict_revision &&
1668             options.upstream &&
1669             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
1670                 int flag;
1671
1672                 if (!(options.flags & REBASE_FORCE)) {
1673                         /* Lazily switch to the target branch if needed... */
1674                         if (options.switch_to) {
1675                                 struct object_id oid;
1676
1677                                 if (get_oid(options.switch_to, &oid) < 0) {
1678                                         ret = !!error(_("could not parse '%s'"),
1679                                                       options.switch_to);
1680                                         goto cleanup;
1681                                 }
1682
1683                                 strbuf_reset(&buf);
1684                                 strbuf_addf(&buf, "%s: checkout %s",
1685                                             getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
1686                                             options.switch_to);
1687                                 if (reset_head(&oid, "checkout",
1688                                                options.head_name,
1689                                                RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
1690                                                NULL, buf.buf) < 0) {
1691                                         ret = !!error(_("could not switch to "
1692                                                         "%s"),
1693                                                       options.switch_to);
1694                                         goto cleanup;
1695                                 }
1696                         }
1697
1698                         if (!(options.flags & REBASE_NO_QUIET))
1699                                 ; /* be quiet */
1700                         else if (!strcmp(branch_name, "HEAD") &&
1701                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1702                                 puts(_("HEAD is up to date."));
1703                         else
1704                                 printf(_("Current branch %s is up to date.\n"),
1705                                        branch_name);
1706                         ret = !!finish_rebase(&options);
1707                         goto cleanup;
1708                 } else if (!(options.flags & REBASE_NO_QUIET))
1709                         ; /* be quiet */
1710                 else if (!strcmp(branch_name, "HEAD") &&
1711                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1712                         puts(_("HEAD is up to date, rebase forced."));
1713                 else
1714                         printf(_("Current branch %s is up to date, rebase "
1715                                  "forced.\n"), branch_name);
1716         }
1717
1718         /* If a hook exists, give it a chance to interrupt*/
1719         if (!ok_to_skip_pre_rebase &&
1720             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
1721                         argc ? argv[0] : NULL, NULL))
1722                 die(_("The pre-rebase hook refused to rebase."));
1723
1724         if (options.flags & REBASE_DIFFSTAT) {
1725                 struct diff_options opts;
1726
1727                 if (options.flags & REBASE_VERBOSE) {
1728                         if (is_null_oid(&merge_base))
1729                                 printf(_("Changes to %s:\n"),
1730                                        oid_to_hex(&options.onto->object.oid));
1731                         else
1732                                 printf(_("Changes from %s to %s:\n"),
1733                                        oid_to_hex(&merge_base),
1734                                        oid_to_hex(&options.onto->object.oid));
1735                 }
1736
1737                 /* We want color (if set), but no pager */
1738                 diff_setup(&opts);
1739                 opts.stat_width = -1; /* use full terminal width */
1740                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
1741                 opts.output_format |=
1742                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
1743                 opts.detect_rename = DIFF_DETECT_RENAME;
1744                 diff_setup_done(&opts);
1745                 diff_tree_oid(is_null_oid(&merge_base) ?
1746                               the_hash_algo->empty_tree : &merge_base,
1747                               &options.onto->object.oid, "", &opts);
1748                 diffcore_std(&opts);
1749                 diff_flush(&opts);
1750         }
1751
1752         if (is_interactive(&options))
1753                 goto run_rebase;
1754
1755         /* Detach HEAD and reset the tree */
1756         if (options.flags & REBASE_NO_QUIET)
1757                 printf(_("First, rewinding head to replay your work on top of "
1758                          "it...\n"));
1759
1760         strbuf_addf(&msg, "%s: checkout %s",
1761                     getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
1762         if (reset_head(&options.onto->object.oid, "checkout", NULL,
1763                        RESET_HEAD_DETACH | RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
1764                        NULL, msg.buf))
1765                 die(_("Could not detach HEAD"));
1766         strbuf_release(&msg);
1767
1768         /*
1769          * If the onto is a proper descendant of the tip of the branch, then
1770          * we just fast-forwarded.
1771          */
1772         strbuf_reset(&msg);
1773         if (!oidcmp(&merge_base, &options.orig_head)) {
1774                 printf(_("Fast-forwarded %s to %s.\n"),
1775                         branch_name, options.onto_name);
1776                 strbuf_addf(&msg, "rebase finished: %s onto %s",
1777                         options.head_name ? options.head_name : "detached HEAD",
1778                         oid_to_hex(&options.onto->object.oid));
1779                 reset_head(NULL, "Fast-forwarded", options.head_name, 0,
1780                            "HEAD", msg.buf);
1781                 strbuf_release(&msg);
1782                 ret = !!finish_rebase(&options);
1783                 goto cleanup;
1784         }
1785
1786         strbuf_addf(&revisions, "%s..%s",
1787                     options.root ? oid_to_hex(&options.onto->object.oid) :
1788                     (options.restrict_revision ?
1789                      oid_to_hex(&options.restrict_revision->object.oid) :
1790                      oid_to_hex(&options.upstream->object.oid)),
1791                     oid_to_hex(&options.orig_head));
1792
1793         options.revisions = revisions.buf;
1794
1795 run_rebase:
1796         ret = !!run_specific_rebase(&options);
1797
1798 cleanup:
1799         strbuf_release(&revisions);
1800         free(options.head_name);
1801         free(options.gpg_sign_opt);
1802         free(options.cmd);
1803         free(squash_onto_name);
1804         return ret;
1805 }