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 #include "commit-reach.h"
  25
  26 static char const * const builtin_rebase_usage[] = {
  27         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  28                 "[<upstream>] [<branch>]"),
  29         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  30                 "--root [<branch>]"),
  31         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  32         NULL
  33 };
  34
  35 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  36 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  37
  38 enum rebase_type {
  39         REBASE_UNSPECIFIED = -1,
  40         REBASE_AM,
  41         REBASE_MERGE,
  42         REBASE_INTERACTIVE,
  43         REBASE_PRESERVE_MERGES
  44 };
  45
  46 static int use_builtin_rebase(void)
  47 {
  48         struct child_process cp = CHILD_PROCESS_INIT;
  49         struct strbuf out = STRBUF_INIT;
  50         int ret;
  51
  52         argv_array_pushl(&cp.args,
  53                          "config", "--bool", "rebase.usebuiltin", NULL);
  54         cp.git_cmd = 1;
  55         if (capture_command(&cp, &out, 6)) {
  56                 strbuf_release(&out);
  57                 return 0;
  58         }
  59
  60         strbuf_trim(&out);
  61         ret = !strcmp("true", out.buf);
  62         strbuf_release(&out);
  63         return ret;
  64 }
  65
  66 static int apply_autostash(void)
  67 {
  68         warning("TODO");
  69         return 0;
  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 commit *restrict_revision;
  86         int dont_finish_rebase;
  87         enum {
  88                 REBASE_NO_QUIET = 1<<0,
  89                 REBASE_VERBOSE = 1<<1,
  90                 REBASE_DIFFSTAT = 1<<2,
  91                 REBASE_FORCE = 1<<3,
  92                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  93         } flags;
  94         struct strbuf git_am_opt;
  95 };
  96
  97 static int is_interactive(struct rebase_options *opts)
  98 {
  99         return opts->type == REBASE_INTERACTIVE ||
 100                 opts->type == REBASE_PRESERVE_MERGES;
 101 }
 102
 103 /* Returns the filename prefixed by the state_dir */
 104 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 105 {
 106         static struct strbuf path = STRBUF_INIT;
 107         static size_t prefix_len;
 108
 109         if (!prefix_len) {
 110                 strbuf_addf(&path, "%s/", opts->state_dir);
 111                 prefix_len = path.len;
 112         }
 113
 114         strbuf_setlen(&path, prefix_len);
 115         strbuf_addstr(&path, filename);
 116         return path.buf;
 117 }
 118
 119 static int finish_rebase(struct rebase_options *opts)
 120 {
 121         struct strbuf dir = STRBUF_INIT;
 122         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 123
 124         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 125         apply_autostash();
 126         close_all_packs(the_repository->objects);
 127         /*
 128          * We ignore errors in 'gc --auto', since the
 129          * user should see them.
 130          */
 131         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 132         strbuf_addstr(&dir, opts->state_dir);
 133         remove_dir_recursively(&dir, 0);
 134         strbuf_release(&dir);
 135
 136         return 0;
 137 }
 138
 139 static struct commit *peel_committish(const char *name)
 140 {
 141         struct object *obj;
 142         struct object_id oid;
 143
 144         if (get_oid(name, &oid))
 145                 return NULL;
 146         obj = parse_object(the_repository, &oid);
 147         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 148 }
 149
 150 static void add_var(struct strbuf *buf, const char *name, const char *value)
 151 {
 152         if (!value)
 153                 strbuf_addf(buf, "unset %s; ", name);
 154         else {
 155                 strbuf_addf(buf, "%s=", name);
 156                 sq_quote_buf(buf, value);
 157                 strbuf_addstr(buf, "; ");
 158         }
 159 }
 160
 161 static int run_specific_rebase(struct rebase_options *opts)
 162 {
 163         const char *argv[] = { NULL, NULL };
 164         struct strbuf script_snippet = STRBUF_INIT;
 165         int status;
 166         const char *backend, *backend_func;
 167
 168         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 169         add_var(&script_snippet, "state_dir", opts->state_dir);
 170
 171         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 172         add_var(&script_snippet, "upstream",
 173                                  oid_to_hex(&opts->upstream->object.oid));
 174         add_var(&script_snippet, "head_name",
 175                 opts->head_name ? opts->head_name : "detached HEAD");
 176         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 177         add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
 178         add_var(&script_snippet, "onto_name", opts->onto_name);
 179         add_var(&script_snippet, "revisions", opts->revisions);
 180         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 181                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 182         add_var(&script_snippet, "GIT_QUIET",
 183                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 184         add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 185         add_var(&script_snippet, "verbose",
 186                 opts->flags & REBASE_VERBOSE ? "t" : "");
 187         add_var(&script_snippet, "diffstat",
 188                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 189         add_var(&script_snippet, "force_rebase",
 190                 opts->flags & REBASE_FORCE ? "t" : "");
 191         if (opts->switch_to)
 192                 add_var(&script_snippet, "switch_to", opts->switch_to);
 193
 194         switch (opts->type) {
 195         case REBASE_AM:
 196                 backend = "git-rebase--am";
 197                 backend_func = "git_rebase__am";
 198                 break;
 199         case REBASE_INTERACTIVE:
 200                 backend = "git-rebase--interactive";
 201                 backend_func = "git_rebase__interactive";
 202                 break;
 203         case REBASE_MERGE:
 204                 backend = "git-rebase--merge";
 205                 backend_func = "git_rebase__merge";
 206                 break;
 207         case REBASE_PRESERVE_MERGES:
 208                 backend = "git-rebase--preserve-merges";
 209                 backend_func = "git_rebase__preserve_merges";
 210                 break;
 211         default:
 212                 BUG("Unhandled rebase type %d", opts->type);
 213                 break;
 214         }
 215
 216         strbuf_addf(&script_snippet,
 217                     ". git-sh-setup && . git-rebase--common &&"
 218                     " . %s && %s", backend, backend_func);
 219         argv[0] = script_snippet.buf;
 220
 221         status = run_command_v_opt(argv, RUN_USING_SHELL);
 222         if (opts->dont_finish_rebase)
 223                 ; /* do nothing */
 224         else if (status == 0) {
 225                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 226                         finish_rebase(opts);
 227         } else if (status == 2) {
 228                 struct strbuf dir = STRBUF_INIT;
 229
 230                 apply_autostash();
 231                 strbuf_addstr(&dir, opts->state_dir);
 232                 remove_dir_recursively(&dir, 0);
 233                 strbuf_release(&dir);
 234                 die("Nothing to do");
 235         }
 236
 237         strbuf_release(&script_snippet);
 238
 239         return status ? -1 : 0;
 240 }
 241
 242 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 243
 244 static int reset_head(struct object_id *oid, const char *action,
 245                       const char *switch_to_branch, int detach_head)
 246 {
 247         struct object_id head_oid;
 248         struct tree_desc desc;
 249         struct lock_file lock = LOCK_INIT;
 250         struct unpack_trees_options unpack_tree_opts;
 251         struct tree *tree;
 252         const char *reflog_action;
 253         struct strbuf msg = STRBUF_INIT;
 254         size_t prefix_len;
 255         struct object_id *orig = NULL, oid_orig,
 256                 *old_orig = NULL, oid_old_orig;
 257         int ret = 0;
 258
 259         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 260                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 261
 262         if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 263                 return -1;
 264
 265         if (!oid) {
 266                 if (get_oid("HEAD", &head_oid)) {
 267                         rollback_lock_file(&lock);
 268                         return error(_("could not determine HEAD revision"));
 269                 }
 270                 oid = &head_oid;
 271         }
 272
 273         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 274         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 275         unpack_tree_opts.head_idx = 1;
 276         unpack_tree_opts.src_index = the_repository->index;
 277         unpack_tree_opts.dst_index = the_repository->index;
 278         unpack_tree_opts.fn = oneway_merge;
 279         unpack_tree_opts.update = 1;
 280         unpack_tree_opts.merge = 1;
 281         if (!detach_head)
 282                 unpack_tree_opts.reset = 1;
 283
 284         if (read_index_unmerged(the_repository->index) < 0) {
 285                 rollback_lock_file(&lock);
 286                 return error(_("could not read index"));
 287         }
 288
 289         if (!fill_tree_descriptor(&desc, oid)) {
 290                 error(_("failed to find tree of %s"), oid_to_hex(oid));
 291                 rollback_lock_file(&lock);
 292                 free((void *)desc.buffer);
 293                 return -1;
 294         }
 295
 296         if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 297                 rollback_lock_file(&lock);
 298                 free((void *)desc.buffer);
 299                 return -1;
 300         }
 301
 302         tree = parse_tree_indirect(oid);
 303         prime_cache_tree(the_repository->index, tree);
 304
 305         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 306                 ret = error(_("could not write index"));
 307         free((void *)desc.buffer);
 308
 309         if (ret)
 310                 return ret;
 311
 312         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 313         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 314         prefix_len = msg.len;
 315
 316         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 317                 old_orig = &oid_old_orig;
 318         if (!get_oid("HEAD", &oid_orig)) {
 319                 orig = &oid_orig;
 320                 strbuf_addstr(&msg, "updating ORIG_HEAD");
 321                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 322                            UPDATE_REFS_MSG_ON_ERR);
 323         } else if (old_orig)
 324                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 325         strbuf_setlen(&msg, prefix_len);
 326         strbuf_addstr(&msg, "updating HEAD");
 327         if (!switch_to_branch)
 328                 ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
 329                                  UPDATE_REFS_MSG_ON_ERR);
 330         else {
 331                 ret = create_symref("HEAD", switch_to_branch, msg.buf);
 332                 if (!ret)
 333                         ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
 334                                          UPDATE_REFS_MSG_ON_ERR);
 335         }
 336
 337         strbuf_release(&msg);
 338         return ret;
 339 }
 340
 341 static int rebase_config(const char *var, const char *value, void *data)
 342 {
 343         struct rebase_options *opts = data;
 344
 345         if (!strcmp(var, "rebase.stat")) {
 346                 if (git_config_bool(var, value))
 347                         opts->flags |= REBASE_DIFFSTAT;
 348                 else
 349                         opts->flags &= !REBASE_DIFFSTAT;
 350                 return 0;
 351         }
 352
 353         return git_default_config(var, value, data);
 354 }
 355
 356 /*
 357  * Determines whether the commits in from..to are linear, i.e. contain
 358  * no merge commits. This function *expects* `from` to be an ancestor of
 359  * `to`.
 360  */
 361 static int is_linear_history(struct commit *from, struct commit *to)
 362 {
 363         while (to && to != from) {
 364                 parse_commit(to);
 365                 if (!to->parents)
 366                         return 1;
 367                 if (to->parents->next)
 368                         return 0;
 369                 to = to->parents->item;
 370         }
 371         return 1;
 372 }
 373
 374 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 375                             struct object_id *merge_base)
 376 {
 377         struct commit *head = lookup_commit(the_repository, head_oid);
 378         struct commit_list *merge_bases;
 379         int res;
 380
 381         if (!head)
 382                 return 0;
 383
 384         merge_bases = get_merge_bases(onto, head);
 385         if (merge_bases && !merge_bases->next) {
 386                 oidcpy(merge_base, &merge_bases->item->object.oid);
 387                 res = !oidcmp(merge_base, &onto->object.oid);
 388         } else {
 389                 oidcpy(merge_base, &null_oid);
 390                 res = 0;
 391         }
 392         free_commit_list(merge_bases);
 393         return res && is_linear_history(onto, head);
 394 }
 395
 396 int cmd_rebase(int argc, const char **argv, const char *prefix)
 397 {
 398         struct rebase_options options = {
 399                 .type = REBASE_UNSPECIFIED,
 400                 .flags = REBASE_NO_QUIET,
 401                 .git_am_opt = STRBUF_INIT,
 402         };
 403         const char *branch_name;
 404         int ret, flags, in_progress = 0;
 405         int ok_to_skip_pre_rebase = 0;
 406         struct strbuf msg = STRBUF_INIT;
 407         struct strbuf revisions = STRBUF_INIT;
 408         struct strbuf buf = STRBUF_INIT;
 409         struct object_id merge_base;
 410         struct option builtin_rebase_options[] = {
 411                 OPT_STRING(0, "onto", &options.onto_name,
 412                            N_("revision"),
 413                            N_("rebase onto given branch instead of upstream")),
 414                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 415                          N_("allow pre-rebase hook to run")),
 416                 OPT_NEGBIT('q', "quiet", &options.flags,
 417                            N_("be quiet. implies --no-stat"),
 418                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 419                 OPT_BIT('v', "verbose", &options.flags,
 420                         N_("display a diffstat of what changed upstream"),
 421                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 422                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 423                         N_("do not show diffstat of what changed upstream"),
 424                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 425                 OPT_BIT('f', "force-rebase", &options.flags,
 426                         N_("cherry-pick all commits, even if unchanged"),
 427                         REBASE_FORCE),
 428                 OPT_BIT(0, "no-ff", &options.flags,
 429                         N_("cherry-pick all commits, even if unchanged"),
 430                         REBASE_FORCE),
 431                 OPT_END(),
 432         };
 433
 434         /*
 435          * NEEDSWORK: Once the builtin rebase has been tested enough
 436          * and git-legacy-rebase.sh is retired to contrib/, this preamble
 437          * can be removed.
 438          */
 439
 440         if (!use_builtin_rebase()) {
 441                 const char *path = mkpath("%s/git-legacy-rebase",
 442                                           git_exec_path());
 443
 444                 if (sane_execvp(path, (char **)argv) < 0)
 445                         die_errno(_("could not exec %s"), path);
 446                 else
 447                         BUG("sane_execvp() returned???");
 448         }
 449
 450         if (argc == 2 && !strcmp(argv[1], "-h"))
 451                 usage_with_options(builtin_rebase_usage,
 452                                    builtin_rebase_options);
 453
 454         prefix = setup_git_directory();
 455         trace_repo_setup(prefix);
 456         setup_work_tree();
 457
 458         git_config(rebase_config, &options);
 459
 460         if (is_directory(apply_dir())) {
 461                 options.type = REBASE_AM;
 462                 options.state_dir = apply_dir();
 463         } else if (is_directory(merge_dir())) {
 464                 strbuf_reset(&buf);
 465                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
 466                 if (is_directory(buf.buf)) {
 467                         options.type = REBASE_PRESERVE_MERGES;
 468                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 469                 } else {
 470                         strbuf_reset(&buf);
 471                         strbuf_addf(&buf, "%s/interactive", merge_dir());
 472                         if(file_exists(buf.buf)) {
 473                                 options.type = REBASE_INTERACTIVE;
 474                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 475                         } else
 476                                 options.type = REBASE_MERGE;
 477                 }
 478                 options.state_dir = merge_dir();
 479         }
 480
 481         if (options.type != REBASE_UNSPECIFIED)
 482                 in_progress = 1;
 483
 484         argc = parse_options(argc, argv, prefix,
 485                              builtin_rebase_options,
 486                              builtin_rebase_usage, 0);
 487
 488         if (argc > 2)
 489                 usage_with_options(builtin_rebase_usage,
 490                                    builtin_rebase_options);
 491
 492         /* Make sure no rebase is in progress */
 493         if (in_progress) {
 494                 const char *last_slash = strrchr(options.state_dir, '/');
 495                 const char *state_dir_base =
 496                         last_slash ? last_slash + 1 : options.state_dir;
 497                 const char *cmd_live_rebase =
 498                         "git rebase (--continue | --abort | --skip)";
 499                 strbuf_reset(&buf);
 500                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
 501                 die(_("It seems that there is already a %s directory, and\n"
 502                       "I wonder if you are in the middle of another rebase.  "
 503                       "If that is the\n"
 504                       "case, please try\n\t%s\n"
 505                       "If that is not the case, please\n\t%s\n"
 506                       "and run me again.  I am stopping in case you still "
 507                       "have something\n"
 508                       "valuable there.\n"),
 509                     state_dir_base, cmd_live_rebase, buf.buf);
 510         }
 511
 512         if (!(options.flags & REBASE_NO_QUIET))
 513                 strbuf_addstr(&options.git_am_opt, " -q");
 514
 515         switch (options.type) {
 516         case REBASE_MERGE:
 517         case REBASE_INTERACTIVE:
 518         case REBASE_PRESERVE_MERGES:
 519                 options.state_dir = merge_dir();
 520                 break;
 521         case REBASE_AM:
 522                 options.state_dir = apply_dir();
 523                 break;
 524         default:
 525                 /* the default rebase backend is `--am` */
 526                 options.type = REBASE_AM;
 527                 options.state_dir = apply_dir();
 528                 break;
 529         }
 530
 531         if (!options.root) {
 532                 if (argc < 1)
 533                         die("TODO: handle @{upstream}");
 534                 else {
 535                         options.upstream_name = argv[0];
 536                         argc--;
 537                         argv++;
 538                         if (!strcmp(options.upstream_name, "-"))
 539                                 options.upstream_name = "@{-1}";
 540                 }
 541                 options.upstream = peel_committish(options.upstream_name);
 542                 if (!options.upstream)
 543                         die(_("invalid upstream '%s'"), options.upstream_name);
 544                 options.upstream_arg = options.upstream_name;
 545         } else
 546                 die("TODO: upstream for --root");
 547
 548         /* Make sure the branch to rebase onto is valid. */
 549         if (!options.onto_name)
 550                 options.onto_name = options.upstream_name;
 551         if (strstr(options.onto_name, "...")) {
 552                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
 553                         die(_("'%s': need exactly one merge base"),
 554                             options.onto_name);
 555                 options.onto = lookup_commit_or_die(&merge_base,
 556                                                     options.onto_name);
 557         } else {
 558                 options.onto = peel_committish(options.onto_name);
 559                 if (!options.onto)
 560                         die(_("Does not point to a valid commit '%s'"),
 561                                 options.onto_name);
 562         }
 563
 564         /*
 565          * If the branch to rebase is given, that is the branch we will rebase
 566          * branch_name -- branch/commit being rebased, or
 567          *                HEAD (already detached)
 568          * orig_head -- commit object name of tip of the branch before rebasing
 569          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
 570          */
 571         if (argc == 1) {
 572                 /* Is it "rebase other branchname" or "rebase other commit"? */
 573                 branch_name = argv[0];
 574                 options.switch_to = argv[0];
 575
 576                 /* Is it a local branch? */
 577                 strbuf_reset(&buf);
 578                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
 579                 if (!read_ref(buf.buf, &options.orig_head))
 580                         options.head_name = xstrdup(buf.buf);
 581                 /* If not is it a valid ref (branch or commit)? */
 582                 else if (!get_oid(branch_name, &options.orig_head))
 583                         options.head_name = NULL;
 584                 else
 585                         die(_("fatal: no such branch/commit '%s'"),
 586                             branch_name);
 587         } else if (argc == 0) {
 588                 /* Do not need to switch branches, we are already on it. */
 589                 options.head_name =
 590                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
 591                                          &flags));
 592                 if (!options.head_name)
 593                         die(_("No such ref: %s"), "HEAD");
 594                 if (flags & REF_ISSYMREF) {
 595                         if (!skip_prefix(options.head_name,
 596                                          "refs/heads/", &branch_name))
 597                                 branch_name = options.head_name;
 598
 599                 } else {
 600                         free(options.head_name);
 601                         options.head_name = NULL;
 602                         branch_name = "HEAD";
 603                 }
 604                 if (get_oid("HEAD", &options.orig_head))
 605                         die(_("Could not resolve HEAD to a revision"));
 606         } else
 607                 BUG("unexpected number of arguments left to parse");
 608
 609         if (read_index(the_repository->index) < 0)
 610                 die(_("could not read index"));
 611
 612         if (require_clean_work_tree("rebase",
 613                                     _("Please commit or stash them."), 1, 1)) {
 614                 ret = 1;
 615                 goto cleanup;
 616         }
 617
 618         /*
 619          * Now we are rebasing commits upstream..orig_head (or with --root,
 620          * everything leading up to orig_head) on top of onto.
 621          */
 622
 623         /*
 624          * Check if we are already based on onto with linear history,
 625          * but this should be done only when upstream and onto are the same
 626          * and if this is not an interactive rebase.
 627          */
 628         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
 629             !is_interactive(&options) && !options.restrict_revision &&
 630             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
 631                 int flag;
 632
 633                 if (!(options.flags & REBASE_FORCE)) {
 634                         /* Lazily switch to the target branch if needed... */
 635                         if (options.switch_to) {
 636                                 struct object_id oid;
 637
 638                                 if (get_oid(options.switch_to, &oid) < 0) {
 639                                         ret = !!error(_("could not parse '%s'"),
 640                                                       options.switch_to);
 641                                         goto cleanup;
 642                                 }
 643
 644                                 strbuf_reset(&buf);
 645                                 strbuf_addf(&buf, "rebase: checkout %s",
 646                                             options.switch_to);
 647                                 if (reset_head(&oid, "checkout",
 648                                                options.head_name, 0) < 0) {
 649                                         ret = !!error(_("could not switch to "
 650                                                         "%s"),
 651                                                       options.switch_to);
 652                                         goto cleanup;
 653                                 }
 654                         }
 655
 656                         if (!(options.flags & REBASE_NO_QUIET))
 657                                 ; /* be quiet */
 658                         else if (!strcmp(branch_name, "HEAD") &&
 659                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 660                                 puts(_("HEAD is up to date."));
 661                         else
 662                                 printf(_("Current branch %s is up to date.\n"),
 663                                        branch_name);
 664                         ret = !!finish_rebase(&options);
 665                         goto cleanup;
 666                 } else if (!(options.flags & REBASE_NO_QUIET))
 667                         ; /* be quiet */
 668                 else if (!strcmp(branch_name, "HEAD") &&
 669                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 670                         puts(_("HEAD is up to date, rebase forced."));
 671                 else
 672                         printf(_("Current branch %s is up to date, rebase "
 673                                  "forced.\n"), branch_name);
 674         }
 675
 676         /* If a hook exists, give it a chance to interrupt*/
 677         if (!ok_to_skip_pre_rebase &&
 678             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
 679                         argc ? argv[0] : NULL, NULL))
 680                 die(_("The pre-rebase hook refused to rebase."));
 681
 682         if (options.flags & REBASE_DIFFSTAT) {
 683                 struct diff_options opts;
 684
 685                 if (options.flags & REBASE_VERBOSE)
 686                         printf(_("Changes from %s to %s:\n"),
 687                                 oid_to_hex(&merge_base),
 688                                 oid_to_hex(&options.onto->object.oid));
 689
 690                 /* We want color (if set), but no pager */
 691                 diff_setup(&opts);
 692                 opts.stat_width = -1; /* use full terminal width */
 693                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
 694                 opts.output_format |=
 695                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 696                 opts.detect_rename = DIFF_DETECT_RENAME;
 697                 diff_setup_done(&opts);
 698                 diff_tree_oid(&merge_base, &options.onto->object.oid,
 699                               "", &opts);
 700                 diffcore_std(&opts);
 701                 diff_flush(&opts);
 702         }
 703
 704         /* Detach HEAD and reset the tree */
 705         if (options.flags & REBASE_NO_QUIET)
 706                 printf(_("First, rewinding head to replay your work on top of "
 707                          "it...\n"));
 708
 709         strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
 710         if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
 711                 die(_("Could not detach HEAD"));
 712         strbuf_release(&msg);
 713
 714         strbuf_addf(&revisions, "%s..%s",
 715                     options.root ? oid_to_hex(&options.onto->object.oid) :
 716                     (options.restrict_revision ?
 717                      oid_to_hex(&options.restrict_revision->object.oid) :
 718                      oid_to_hex(&options.upstream->object.oid)),
 719                     oid_to_hex(&options.orig_head));
 720
 721         options.revisions = revisions.buf;
 722
 723         ret = !!run_specific_rebase(&options);
 724
 725 cleanup:
 726         strbuf_release(&revisions);
 727         free(options.head_name);
 728         return ret;
 729 }