git.oblomov.eu Git - git/blob - builtin/rebase.c

   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
  25 static char const * const builtin_rebase_usage[] = {
  26         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  27                 "[<upstream>] [<branch>]"),
  28         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  29                 "--root [<branch>]"),
  30         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  31         NULL
  32 };
  33
  34 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  35 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  36
  37 enum rebase_type {
  38         REBASE_UNSPECIFIED = -1,
  39         REBASE_AM,
  40         REBASE_MERGE,
  41         REBASE_INTERACTIVE,
  42         REBASE_PRESERVE_MERGES
  43 };
  44
  45 static int use_builtin_rebase(void)
  46 {
  47         struct child_process cp = CHILD_PROCESS_INIT;
  48         struct strbuf out = STRBUF_INIT;
  49         int ret;
  50
  51         argv_array_pushl(&cp.args,
  52                          "config", "--bool", "rebase.usebuiltin", NULL);
  53         cp.git_cmd = 1;
  54         if (capture_command(&cp, &out, 6)) {
  55                 strbuf_release(&out);
  56                 return 0;
  57         }
  58
  59         strbuf_trim(&out);
  60         ret = !strcmp("true", out.buf);
  61         strbuf_release(&out);
  62         return ret;
  63 }
  64
  65 static int apply_autostash(void)
  66 {
  67         warning("TODO");
  68         return 0;
  69 }
  70
  71 struct rebase_options {
  72         enum rebase_type type;
  73         const char *state_dir;
  74         struct commit *upstream;
  75         const char *upstream_name;
  76         const char *upstream_arg;
  77         char *head_name;
  78         struct object_id orig_head;
  79         struct commit *onto;
  80         const char *onto_name;
  81         const char *revisions;
  82         const char *switch_to;
  83         int root;
  84         struct commit *restrict_revision;
  85         int dont_finish_rebase;
  86         enum {
  87                 REBASE_NO_QUIET = 1<<0,
  88                 REBASE_VERBOSE = 1<<1,
  89                 REBASE_DIFFSTAT = 1<<2,
  90                 REBASE_FORCE = 1<<3,
  91                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  92         } flags;
  93         struct strbuf git_am_opt;
  94 };
  95
  96 static int is_interactive(struct rebase_options *opts)
  97 {
  98         return opts->type == REBASE_INTERACTIVE ||
  99                 opts->type == REBASE_PRESERVE_MERGES;
 100 }
 101
 102 /* Returns the filename prefixed by the state_dir */
 103 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 104 {
 105         static struct strbuf path = STRBUF_INIT;
 106         static size_t prefix_len;
 107
 108         if (!prefix_len) {
 109                 strbuf_addf(&path, "%s/", opts->state_dir);
 110                 prefix_len = path.len;
 111         }
 112
 113         strbuf_setlen(&path, prefix_len);
 114         strbuf_addstr(&path, filename);
 115         return path.buf;
 116 }
 117
 118 static int finish_rebase(struct rebase_options *opts)
 119 {
 120         struct strbuf dir = STRBUF_INIT;
 121         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 122
 123         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 124         apply_autostash();
 125         close_all_packs(the_repository->objects);
 126         /*
 127          * We ignore errors in 'gc --auto', since the
 128          * user should see them.
 129          */
 130         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 131         strbuf_addstr(&dir, opts->state_dir);
 132         remove_dir_recursively(&dir, 0);
 133         strbuf_release(&dir);
 134
 135         return 0;
 136 }
 137
 138 static struct commit *peel_committish(const char *name)
 139 {
 140         struct object *obj;
 141         struct object_id oid;
 142
 143         if (get_oid(name, &oid))
 144                 return NULL;
 145         obj = parse_object(the_repository, &oid);
 146         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 147 }
 148
 149 static void add_var(struct strbuf *buf, const char *name, const char *value)
 150 {
 151         if (!value)
 152                 strbuf_addf(buf, "unset %s; ", name);
 153         else {
 154                 strbuf_addf(buf, "%s=", name);
 155                 sq_quote_buf(buf, value);
 156                 strbuf_addstr(buf, "; ");
 157         }
 158 }
 159
 160 static int run_specific_rebase(struct rebase_options *opts)
 161 {
 162         const char *argv[] = { NULL, NULL };
 163         struct strbuf script_snippet = STRBUF_INIT;
 164         int status;
 165         const char *backend, *backend_func;
 166
 167         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 168         add_var(&script_snippet, "state_dir", opts->state_dir);
 169
 170         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 171         add_var(&script_snippet, "upstream",
 172                                  oid_to_hex(&opts->upstream->object.oid));
 173         add_var(&script_snippet, "head_name",
 174                 opts->head_name ? opts->head_name : "detached HEAD");
 175         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 176         add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
 177         add_var(&script_snippet, "onto_name", opts->onto_name);
 178         add_var(&script_snippet, "revisions", opts->revisions);
 179         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 180                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 181         add_var(&script_snippet, "GIT_QUIET",
 182                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 183         add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 184         add_var(&script_snippet, "verbose",
 185                 opts->flags & REBASE_VERBOSE ? "t" : "");
 186         add_var(&script_snippet, "diffstat",
 187                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 188         add_var(&script_snippet, "force_rebase",
 189                 opts->flags & REBASE_FORCE ? "t" : "");
 190         if (opts->switch_to)
 191                 add_var(&script_snippet, "switch_to", opts->switch_to);
 192
 193         switch (opts->type) {
 194         case REBASE_AM:
 195                 backend = "git-rebase--am";
 196                 backend_func = "git_rebase__am";
 197                 break;
 198         case REBASE_INTERACTIVE:
 199                 backend = "git-rebase--interactive";
 200                 backend_func = "git_rebase__interactive";
 201                 break;
 202         case REBASE_MERGE:
 203                 backend = "git-rebase--merge";
 204                 backend_func = "git_rebase__merge";
 205                 break;
 206         case REBASE_PRESERVE_MERGES:
 207                 backend = "git-rebase--preserve-merges";
 208                 backend_func = "git_rebase__preserve_merges";
 209                 break;
 210         default:
 211                 BUG("Unhandled rebase type %d", opts->type);
 212                 break;
 213         }
 214
 215         strbuf_addf(&script_snippet,
 216                     ". git-sh-setup && . git-rebase--common &&"
 217                     " . %s && %s", backend, backend_func);
 218         argv[0] = script_snippet.buf;
 219
 220         status = run_command_v_opt(argv, RUN_USING_SHELL);
 221         if (opts->dont_finish_rebase)
 222                 ; /* do nothing */
 223         else if (status == 0) {
 224                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 225                         finish_rebase(opts);
 226         } else if (status == 2) {
 227                 struct strbuf dir = STRBUF_INIT;
 228
 229                 apply_autostash();
 230                 strbuf_addstr(&dir, opts->state_dir);
 231                 remove_dir_recursively(&dir, 0);
 232                 strbuf_release(&dir);
 233                 die("Nothing to do");
 234         }
 235
 236         strbuf_release(&script_snippet);
 237
 238         return status ? -1 : 0;
 239 }
 240
 241 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 242
 243 static int reset_head(struct object_id *oid, const char *action,
 244                       const char *switch_to_branch, int detach_head)
 245 {
 246         struct object_id head_oid;
 247         struct tree_desc desc;
 248         struct lock_file lock = LOCK_INIT;
 249         struct unpack_trees_options unpack_tree_opts;
 250         struct tree *tree;
 251         const char *reflog_action;
 252         struct strbuf msg = STRBUF_INIT;
 253         size_t prefix_len;
 254         struct object_id *orig = NULL, oid_orig,
 255                 *old_orig = NULL, oid_old_orig;
 256         int ret = 0;
 257
 258         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 259                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 260
 261         if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 262                 return -1;
 263
 264         if (!oid) {
 265                 if (get_oid("HEAD", &head_oid)) {
 266                         rollback_lock_file(&lock);
 267                         return error(_("could not determine HEAD revision"));
 268                 }
 269                 oid = &head_oid;
 270         }
 271
 272         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 273         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 274         unpack_tree_opts.head_idx = 1;
 275         unpack_tree_opts.src_index = the_repository->index;
 276         unpack_tree_opts.dst_index = the_repository->index;
 277         unpack_tree_opts.fn = oneway_merge;
 278         unpack_tree_opts.update = 1;
 279         unpack_tree_opts.merge = 1;
 280         if (!detach_head)
 281                 unpack_tree_opts.reset = 1;
 282
 283         if (read_index_unmerged(the_repository->index) < 0) {
 284                 rollback_lock_file(&lock);
 285                 return error(_("could not read index"));
 286         }
 287
 288         if (!fill_tree_descriptor(&desc, oid)) {
 289                 error(_("failed to find tree of %s"), oid_to_hex(oid));
 290                 rollback_lock_file(&lock);
 291                 free((void *)desc.buffer);
 292                 return -1;
 293         }
 294
 295         if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 296                 rollback_lock_file(&lock);
 297                 free((void *)desc.buffer);
 298                 return -1;
 299         }
 300
 301         tree = parse_tree_indirect(oid);
 302         prime_cache_tree(the_repository->index, tree);
 303
 304         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 305                 ret = error(_("could not write index"));
 306         free((void *)desc.buffer);
 307
 308         if (ret)
 309                 return ret;
 310
 311         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 312         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 313         prefix_len = msg.len;
 314
 315         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 316                 old_orig = &oid_old_orig;
 317         if (!get_oid("HEAD", &oid_orig)) {
 318                 orig = &oid_orig;
 319                 strbuf_addstr(&msg, "updating ORIG_HEAD");
 320                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 321                            UPDATE_REFS_MSG_ON_ERR);
 322         } else if (old_orig)
 323                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 324         strbuf_setlen(&msg, prefix_len);
 325         strbuf_addstr(&msg, "updating HEAD");
 326         if (!switch_to_branch)
 327                 ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
 328                                  UPDATE_REFS_MSG_ON_ERR);
 329         else {
 330                 ret = create_symref("HEAD", switch_to_branch, msg.buf);
 331                 if (!ret)
 332                         ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
 333                                          UPDATE_REFS_MSG_ON_ERR);
 334         }
 335
 336         strbuf_release(&msg);
 337         return ret;
 338 }
 339
 340 static int rebase_config(const char *var, const char *value, void *data)
 341 {
 342         struct rebase_options *opts = data;
 343
 344         if (!strcmp(var, "rebase.stat")) {
 345                 if (git_config_bool(var, value))
 346                         opts->flags |= REBASE_DIFFSTAT;
 347                 else
 348                         opts->flags &= !REBASE_DIFFSTAT;
 349                 return 0;
 350         }
 351
 352         return git_default_config(var, value, data);
 353 }
 354
 355 /*
 356  * Determines whether the commits in from..to are linear, i.e. contain
 357  * no merge commits. This function *expects* `from` to be an ancestor of
 358  * `to`.
 359  */
 360 static int is_linear_history(struct commit *from, struct commit *to)
 361 {
 362         while (to && to != from) {
 363                 parse_commit(to);
 364                 if (!to->parents)
 365                         return 1;
 366                 if (to->parents->next)
 367                         return 0;
 368                 to = to->parents->item;
 369         }
 370         return 1;
 371 }
 372
 373 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 374                             struct object_id *merge_base)
 375 {
 376         struct commit *head = lookup_commit(the_repository, head_oid);
 377         struct commit_list *merge_bases;
 378         int res;
 379
 380         if (!head)
 381                 return 0;
 382
 383         merge_bases = get_merge_bases(onto, head);
 384         if (merge_bases && !merge_bases->next) {
 385                 oidcpy(merge_base, &merge_bases->item->object.oid);
 386                 res = !oidcmp(merge_base, &onto->object.oid);
 387         } else {
 388                 oidcpy(merge_base, &null_oid);
 389                 res = 0;
 390         }
 391         free_commit_list(merge_bases);
 392         return res && is_linear_history(onto, head);
 393 }
 394
 395 int cmd_rebase(int argc, const char **argv, const char *prefix)
 396 {
 397         struct rebase_options options = {
 398                 .type = REBASE_UNSPECIFIED,
 399                 .flags = REBASE_NO_QUIET,
 400                 .git_am_opt = STRBUF_INIT,
 401         };
 402         const char *branch_name;
 403         int ret, flags, in_progress = 0;
 404         int ok_to_skip_pre_rebase = 0;
 405         struct strbuf msg = STRBUF_INIT;
 406         struct strbuf revisions = STRBUF_INIT;
 407         struct strbuf buf = STRBUF_INIT;
 408         struct object_id merge_base;
 409         struct option builtin_rebase_options[] = {
 410                 OPT_STRING(0, "onto", &options.onto_name,
 411                            N_("revision"),
 412                            N_("rebase onto given branch instead of upstream")),
 413                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 414                          N_("allow pre-rebase hook to run")),
 415                 OPT_NEGBIT('q', "quiet", &options.flags,
 416                            N_("be quiet. implies --no-stat"),
 417                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 418                 OPT_BIT('v', "verbose", &options.flags,
 419                         N_("display a diffstat of what changed upstream"),
 420                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 421                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 422                         N_("do not show diffstat of what changed upstream"),
 423                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 424                 OPT_BIT('f', "force-rebase", &options.flags,
 425                         N_("cherry-pick all commits, even if unchanged"),
 426                         REBASE_FORCE),
 427                 OPT_BIT(0, "no-ff", &options.flags,
 428                         N_("cherry-pick all commits, even if unchanged"),
 429                         REBASE_FORCE),
 430                 OPT_END(),
 431         };
 432
 433         /*
 434          * NEEDSWORK: Once the builtin rebase has been tested enough
 435          * and git-legacy-rebase.sh is retired to contrib/, this preamble
 436          * can be removed.
 437          */
 438
 439         if (!use_builtin_rebase()) {
 440                 const char *path = mkpath("%s/git-legacy-rebase",
 441                                           git_exec_path());
 442
 443                 if (sane_execvp(path, (char **)argv) < 0)
 444                         die_errno(_("could not exec %s"), path);
 445                 else
 446                         BUG("sane_execvp() returned???");
 447         }
 448
 449         if (argc == 2 && !strcmp(argv[1], "-h"))
 450                 usage_with_options(builtin_rebase_usage,
 451                                    builtin_rebase_options);
 452
 453         prefix = setup_git_directory();
 454         trace_repo_setup(prefix);
 455         setup_work_tree();
 456
 457         git_config(rebase_config, &options);
 458
 459         if (is_directory(apply_dir())) {
 460                 options.type = REBASE_AM;
 461                 options.state_dir = apply_dir();
 462         } else if (is_directory(merge_dir())) {
 463                 strbuf_reset(&buf);
 464                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
 465                 if (is_directory(buf.buf)) {
 466                         options.type = REBASE_PRESERVE_MERGES;
 467                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 468                 } else {
 469                         strbuf_reset(&buf);
 470                         strbuf_addf(&buf, "%s/interactive", merge_dir());
 471                         if(file_exists(buf.buf)) {
 472                                 options.type = REBASE_INTERACTIVE;
 473                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 474                         } else
 475                                 options.type = REBASE_MERGE;
 476                 }
 477                 options.state_dir = merge_dir();
 478         }
 479
 480         if (options.type != REBASE_UNSPECIFIED)
 481                 in_progress = 1;
 482
 483         argc = parse_options(argc, argv, prefix,
 484                              builtin_rebase_options,
 485                              builtin_rebase_usage, 0);
 486
 487         if (argc > 2)
 488                 usage_with_options(builtin_rebase_usage,
 489                                    builtin_rebase_options);
 490
 491         /* Make sure no rebase is in progress */
 492         if (in_progress) {
 493                 const char *last_slash = strrchr(options.state_dir, '/');
 494                 const char *state_dir_base =
 495                         last_slash ? last_slash + 1 : options.state_dir;
 496                 const char *cmd_live_rebase =
 497                         "git rebase (--continue | --abort | --skip)";
 498                 strbuf_reset(&buf);
 499                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
 500                 die(_("It seems that there is already a %s directory, and\n"
 501                       "I wonder if you are in the middle of another rebase.  "
 502                       "If that is the\n"
 503                       "case, please try\n\t%s\n"
 504                       "If that is not the case, please\n\t%s\n"
 505                       "and run me again.  I am stopping in case you still "
 506                       "have something\n"
 507                       "valuable there.\n"),
 508                     state_dir_base, cmd_live_rebase, buf.buf);
 509         }
 510
 511         if (!(options.flags & REBASE_NO_QUIET))
 512                 strbuf_addstr(&options.git_am_opt, " -q");
 513
 514         switch (options.type) {
 515         case REBASE_MERGE:
 516         case REBASE_INTERACTIVE:
 517         case REBASE_PRESERVE_MERGES:
 518                 options.state_dir = merge_dir();
 519                 break;
 520         case REBASE_AM:
 521                 options.state_dir = apply_dir();
 522                 break;
 523         default:
 524                 /* the default rebase backend is `--am` */
 525                 options.type = REBASE_AM;
 526                 options.state_dir = apply_dir();
 527                 break;
 528         }
 529
 530         if (!options.root) {
 531                 if (argc < 1)
 532                         die("TODO: handle @{upstream}");
 533                 else {
 534                         options.upstream_name = argv[0];
 535                         argc--;
 536                         argv++;
 537                         if (!strcmp(options.upstream_name, "-"))
 538                                 options.upstream_name = "@{-1}";
 539                 }
 540                 options.upstream = peel_committish(options.upstream_name);
 541                 if (!options.upstream)
 542                         die(_("invalid upstream '%s'"), options.upstream_name);
 543                 options.upstream_arg = options.upstream_name;
 544         } else
 545                 die("TODO: upstream for --root");
 546
 547         /* Make sure the branch to rebase onto is valid. */
 548         if (!options.onto_name)
 549                 options.onto_name = options.upstream_name;
 550         if (strstr(options.onto_name, "...")) {
 551                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
 552                         die(_("'%s': need exactly one merge base"),
 553                             options.onto_name);
 554                 options.onto = lookup_commit_or_die(&merge_base,
 555                                                     options.onto_name);
 556         } else {
 557                 options.onto = peel_committish(options.onto_name);
 558                 if (!options.onto)
 559                         die(_("Does not point to a valid commit '%s'"),
 560                                 options.onto_name);
 561         }
 562
 563         /*
 564          * If the branch to rebase is given, that is the branch we will rebase
 565          * branch_name -- branch/commit being rebased, or
 566          *                HEAD (already detached)
 567          * orig_head -- commit object name of tip of the branch before rebasing
 568          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
 569          */
 570         if (argc == 1) {
 571                 /* Is it "rebase other branchname" or "rebase other commit"? */
 572                 branch_name = argv[0];
 573                 options.switch_to = argv[0];
 574
 575                 /* Is it a local branch? */
 576                 strbuf_reset(&buf);
 577                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
 578                 if (!read_ref(buf.buf, &options.orig_head))
 579                         options.head_name = xstrdup(buf.buf);
 580                 /* If not is it a valid ref (branch or commit)? */
 581                 else if (!get_oid(branch_name, &options.orig_head))
 582                         options.head_name = NULL;
 583                 else
 584                         die(_("fatal: no such branch/commit '%s'"),
 585                             branch_name);
 586         } else if (argc == 0) {
 587                 /* Do not need to switch branches, we are already on it. */
 588                 options.head_name =
 589                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
 590                                          &flags));
 591                 if (!options.head_name)
 592                         die(_("No such ref: %s"), "HEAD");
 593                 if (flags & REF_ISSYMREF) {
 594                         if (!skip_prefix(options.head_name,
 595                                          "refs/heads/", &branch_name))
 596                                 branch_name = options.head_name;
 597
 598                 } else {
 599                         free(options.head_name);
 600                         options.head_name = NULL;
 601                         branch_name = "HEAD";
 602                 }
 603                 if (get_oid("HEAD", &options.orig_head))
 604                         die(_("Could not resolve HEAD to a revision"));
 605         } else
 606                 BUG("unexpected number of arguments left to parse");
 607
 608         if (read_index(the_repository->index) < 0)
 609                 die(_("could not read index"));
 610
 611         if (require_clean_work_tree("rebase",
 612                                     _("Please commit or stash them."), 1, 1)) {
 613                 ret = 1;
 614                 goto cleanup;
 615         }
 616
 617         /*
 618          * Now we are rebasing commits upstream..orig_head (or with --root,
 619          * everything leading up to orig_head) on top of onto.
 620          */
 621
 622         /*
 623          * Check if we are already based on onto with linear history,
 624          * but this should be done only when upstream and onto are the same
 625          * and if this is not an interactive rebase.
 626          */
 627         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
 628             !is_interactive(&options) && !options.restrict_revision &&
 629             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
 630                 int flag;
 631
 632                 if (!(options.flags & REBASE_FORCE)) {
 633                         /* Lazily switch to the target branch if needed... */
 634                         if (options.switch_to) {
 635                                 struct object_id oid;
 636
 637                                 if (get_oid(options.switch_to, &oid) < 0) {
 638                                         ret = !!error(_("could not parse '%s'"),
 639                                                       options.switch_to);
 640                                         goto cleanup;
 641                                 }
 642
 643                                 strbuf_reset(&buf);
 644                                 strbuf_addf(&buf, "rebase: checkout %s",
 645                                             options.switch_to);
 646                                 if (reset_head(&oid, "checkout",
 647                                                options.head_name, 0) < 0) {
 648                                         ret = !!error(_("could not switch to "
 649                                                         "%s"),
 650                                                       options.switch_to);
 651                                         goto cleanup;
 652                                 }
 653                         }
 654
 655                         if (!(options.flags & REBASE_NO_QUIET))
 656                                 ; /* be quiet */
 657                         else if (!strcmp(branch_name, "HEAD") &&
 658                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 659                                 puts(_("HEAD is up to date."));
 660                         else
 661                                 printf(_("Current branch %s is up to date.\n"),
 662                                        branch_name);
 663                         ret = !!finish_rebase(&options);
 664                         goto cleanup;
 665                 } else if (!(options.flags & REBASE_NO_QUIET))
 666                         ; /* be quiet */
 667                 else if (!strcmp(branch_name, "HEAD") &&
 668                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 669                         puts(_("HEAD is up to date, rebase forced."));
 670                 else
 671                         printf(_("Current branch %s is up to date, rebase "
 672                                  "forced.\n"), branch_name);
 673         }
 674
 675         /* If a hook exists, give it a chance to interrupt*/
 676         if (!ok_to_skip_pre_rebase &&
 677             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
 678                         argc ? argv[0] : NULL, NULL))
 679                 die(_("The pre-rebase hook refused to rebase."));
 680
 681         if (options.flags & REBASE_DIFFSTAT) {
 682                 struct diff_options opts;
 683
 684                 if (options.flags & REBASE_VERBOSE)
 685                         printf(_("Changes from %s to %s:\n"),
 686                                 oid_to_hex(&merge_base),
 687                                 oid_to_hex(&options.onto->object.oid));
 688
 689                 /* We want color (if set), but no pager */
 690                 diff_setup(&opts);
 691                 opts.stat_width = -1; /* use full terminal width */
 692                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
 693                 opts.output_format |=
 694                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 695                 opts.detect_rename = DIFF_DETECT_RENAME;
 696                 diff_setup_done(&opts);
 697                 diff_tree_oid(&merge_base, &options.onto->object.oid,
 698                               "", &opts);
 699                 diffcore_std(&opts);
 700                 diff_flush(&opts);
 701         }
 702
 703         /* Detach HEAD and reset the tree */
 704         if (options.flags & REBASE_NO_QUIET)
 705                 printf(_("First, rewinding head to replay your work on top of "
 706                          "it...\n"));
 707
 708         strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
 709         if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
 710                 die(_("Could not detach HEAD"));
 711         strbuf_release(&msg);
 712
 713         strbuf_addf(&revisions, "%s..%s",
 714                     options.root ? oid_to_hex(&options.onto->object.oid) :
 715                     (options.restrict_revision ?
 716                      oid_to_hex(&options.restrict_revision->object.oid) :
 717                      oid_to_hex(&options.upstream->object.oid)),
 718                     oid_to_hex(&options.orig_head));
 719
 720         options.revisions = revisions.buf;
 721
 722         ret = !!run_specific_rebase(&options);
 723
 724 cleanup:
 725         strbuf_release(&revisions);
 726         free(options.head_name);
 727         return ret;
 728 }