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 "rerere.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         const char *action;
  96 };
  97
  98 static int is_interactive(struct rebase_options *opts)
  99 {
 100         return opts->type == REBASE_INTERACTIVE ||
 101                 opts->type == REBASE_PRESERVE_MERGES;
 102 }
 103
 104 /* Returns the filename prefixed by the state_dir */
 105 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 106 {
 107         static struct strbuf path = STRBUF_INIT;
 108         static size_t prefix_len;
 109
 110         if (!prefix_len) {
 111                 strbuf_addf(&path, "%s/", opts->state_dir);
 112                 prefix_len = path.len;
 113         }
 114
 115         strbuf_setlen(&path, prefix_len);
 116         strbuf_addstr(&path, filename);
 117         return path.buf;
 118 }
 119
 120 /* Read one file, then strip line endings */
 121 static int read_one(const char *path, struct strbuf *buf)
 122 {
 123         if (strbuf_read_file(buf, path, 0) < 0)
 124                 return error_errno(_("could not read '%s'"), path);
 125         strbuf_trim_trailing_newline(buf);
 126         return 0;
 127 }
 128
 129 /* Initialize the rebase options from the state directory. */
 130 static int read_basic_state(struct rebase_options *opts)
 131 {
 132         struct strbuf head_name = STRBUF_INIT;
 133         struct strbuf buf = STRBUF_INIT;
 134         struct object_id oid;
 135
 136         if (read_one(state_dir_path("head-name", opts), &head_name) ||
 137             read_one(state_dir_path("onto", opts), &buf))
 138                 return -1;
 139         opts->head_name = starts_with(head_name.buf, "refs/") ?
 140                 xstrdup(head_name.buf) : NULL;
 141         strbuf_release(&head_name);
 142         if (get_oid(buf.buf, &oid))
 143                 return error(_("could not get 'onto': '%s'"), buf.buf);
 144         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 145
 146         /*
 147          * We always write to orig-head, but interactive rebase used to write to
 148          * head. Fall back to reading from head to cover for the case that the
 149          * user upgraded git with an ongoing interactive rebase.
 150          */
 151         strbuf_reset(&buf);
 152         if (file_exists(state_dir_path("orig-head", opts))) {
 153                 if (read_one(state_dir_path("orig-head", opts), &buf))
 154                         return -1;
 155         } else if (read_one(state_dir_path("head", opts), &buf))
 156                 return -1;
 157         if (get_oid(buf.buf, &opts->orig_head))
 158                 return error(_("invalid orig-head: '%s'"), buf.buf);
 159
 160         strbuf_reset(&buf);
 161         if (read_one(state_dir_path("quiet", opts), &buf))
 162                 return -1;
 163         if (buf.len)
 164                 opts->flags &= ~REBASE_NO_QUIET;
 165         else
 166                 opts->flags |= REBASE_NO_QUIET;
 167
 168         if (file_exists(state_dir_path("verbose", opts)))
 169                 opts->flags |= REBASE_VERBOSE;
 170
 171         strbuf_release(&buf);
 172
 173         return 0;
 174 }
 175
 176 static int finish_rebase(struct rebase_options *opts)
 177 {
 178         struct strbuf dir = STRBUF_INIT;
 179         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 180
 181         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 182         apply_autostash();
 183         close_all_packs(the_repository->objects);
 184         /*
 185          * We ignore errors in 'gc --auto', since the
 186          * user should see them.
 187          */
 188         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 189         strbuf_addstr(&dir, opts->state_dir);
 190         remove_dir_recursively(&dir, 0);
 191         strbuf_release(&dir);
 192
 193         return 0;
 194 }
 195
 196 static struct commit *peel_committish(const char *name)
 197 {
 198         struct object *obj;
 199         struct object_id oid;
 200
 201         if (get_oid(name, &oid))
 202                 return NULL;
 203         obj = parse_object(the_repository, &oid);
 204         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 205 }
 206
 207 static void add_var(struct strbuf *buf, const char *name, const char *value)
 208 {
 209         if (!value)
 210                 strbuf_addf(buf, "unset %s; ", name);
 211         else {
 212                 strbuf_addf(buf, "%s=", name);
 213                 sq_quote_buf(buf, value);
 214                 strbuf_addstr(buf, "; ");
 215         }
 216 }
 217
 218 static int run_specific_rebase(struct rebase_options *opts)
 219 {
 220         const char *argv[] = { NULL, NULL };
 221         struct strbuf script_snippet = STRBUF_INIT;
 222         int status;
 223         const char *backend, *backend_func;
 224
 225         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 226         add_var(&script_snippet, "state_dir", opts->state_dir);
 227
 228         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 229         add_var(&script_snippet, "upstream", opts->upstream ?
 230                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 231         add_var(&script_snippet, "head_name",
 232                 opts->head_name ? opts->head_name : "detached HEAD");
 233         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 234         add_var(&script_snippet, "onto", opts->onto ?
 235                 oid_to_hex(&opts->onto->object.oid) : NULL);
 236         add_var(&script_snippet, "onto_name", opts->onto_name);
 237         add_var(&script_snippet, "revisions", opts->revisions);
 238         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 239                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 240         add_var(&script_snippet, "GIT_QUIET",
 241                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 242         add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 243         add_var(&script_snippet, "verbose",
 244                 opts->flags & REBASE_VERBOSE ? "t" : "");
 245         add_var(&script_snippet, "diffstat",
 246                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 247         add_var(&script_snippet, "force_rebase",
 248                 opts->flags & REBASE_FORCE ? "t" : "");
 249         if (opts->switch_to)
 250                 add_var(&script_snippet, "switch_to", opts->switch_to);
 251         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 252
 253         switch (opts->type) {
 254         case REBASE_AM:
 255                 backend = "git-rebase--am";
 256                 backend_func = "git_rebase__am";
 257                 break;
 258         case REBASE_INTERACTIVE:
 259                 backend = "git-rebase--interactive";
 260                 backend_func = "git_rebase__interactive";
 261                 break;
 262         case REBASE_MERGE:
 263                 backend = "git-rebase--merge";
 264                 backend_func = "git_rebase__merge";
 265                 break;
 266         case REBASE_PRESERVE_MERGES:
 267                 backend = "git-rebase--preserve-merges";
 268                 backend_func = "git_rebase__preserve_merges";
 269                 break;
 270         default:
 271                 BUG("Unhandled rebase type %d", opts->type);
 272                 break;
 273         }
 274
 275         strbuf_addf(&script_snippet,
 276                     ". git-sh-setup && . git-rebase--common &&"
 277                     " . %s && %s", backend, backend_func);
 278         argv[0] = script_snippet.buf;
 279
 280         status = run_command_v_opt(argv, RUN_USING_SHELL);
 281         if (opts->dont_finish_rebase)
 282                 ; /* do nothing */
 283         else if (status == 0) {
 284                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 285                         finish_rebase(opts);
 286         } else if (status == 2) {
 287                 struct strbuf dir = STRBUF_INIT;
 288
 289                 apply_autostash();
 290                 strbuf_addstr(&dir, opts->state_dir);
 291                 remove_dir_recursively(&dir, 0);
 292                 strbuf_release(&dir);
 293                 die("Nothing to do");
 294         }
 295
 296         strbuf_release(&script_snippet);
 297
 298         return status ? -1 : 0;
 299 }
 300
 301 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 302
 303 static int reset_head(struct object_id *oid, const char *action,
 304                       const char *switch_to_branch, int detach_head)
 305 {
 306         struct object_id head_oid;
 307         struct tree_desc desc;
 308         struct lock_file lock = LOCK_INIT;
 309         struct unpack_trees_options unpack_tree_opts;
 310         struct tree *tree;
 311         const char *reflog_action;
 312         struct strbuf msg = STRBUF_INIT;
 313         size_t prefix_len;
 314         struct object_id *orig = NULL, oid_orig,
 315                 *old_orig = NULL, oid_old_orig;
 316         int ret = 0;
 317
 318         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 319                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 320
 321         if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 322                 return -1;
 323
 324         if (!oid) {
 325                 if (get_oid("HEAD", &head_oid)) {
 326                         rollback_lock_file(&lock);
 327                         return error(_("could not determine HEAD revision"));
 328                 }
 329                 oid = &head_oid;
 330         }
 331
 332         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 333         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 334         unpack_tree_opts.head_idx = 1;
 335         unpack_tree_opts.src_index = the_repository->index;
 336         unpack_tree_opts.dst_index = the_repository->index;
 337         unpack_tree_opts.fn = oneway_merge;
 338         unpack_tree_opts.update = 1;
 339         unpack_tree_opts.merge = 1;
 340         if (!detach_head)
 341                 unpack_tree_opts.reset = 1;
 342
 343         if (read_index_unmerged(the_repository->index) < 0) {
 344                 rollback_lock_file(&lock);
 345                 return error(_("could not read index"));
 346         }
 347
 348         if (!fill_tree_descriptor(&desc, oid)) {
 349                 error(_("failed to find tree of %s"), oid_to_hex(oid));
 350                 rollback_lock_file(&lock);
 351                 free((void *)desc.buffer);
 352                 return -1;
 353         }
 354
 355         if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 356                 rollback_lock_file(&lock);
 357                 free((void *)desc.buffer);
 358                 return -1;
 359         }
 360
 361         tree = parse_tree_indirect(oid);
 362         prime_cache_tree(the_repository->index, tree);
 363
 364         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 365                 ret = error(_("could not write index"));
 366         free((void *)desc.buffer);
 367
 368         if (ret)
 369                 return ret;
 370
 371         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 372         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 373         prefix_len = msg.len;
 374
 375         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 376                 old_orig = &oid_old_orig;
 377         if (!get_oid("HEAD", &oid_orig)) {
 378                 orig = &oid_orig;
 379                 strbuf_addstr(&msg, "updating ORIG_HEAD");
 380                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 381                            UPDATE_REFS_MSG_ON_ERR);
 382         } else if (old_orig)
 383                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 384         strbuf_setlen(&msg, prefix_len);
 385         strbuf_addstr(&msg, "updating HEAD");
 386         if (!switch_to_branch)
 387                 ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
 388                                  UPDATE_REFS_MSG_ON_ERR);
 389         else {
 390                 ret = create_symref("HEAD", switch_to_branch, msg.buf);
 391                 if (!ret)
 392                         ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
 393                                          UPDATE_REFS_MSG_ON_ERR);
 394         }
 395
 396         strbuf_release(&msg);
 397         return ret;
 398 }
 399
 400 static int rebase_config(const char *var, const char *value, void *data)
 401 {
 402         struct rebase_options *opts = data;
 403
 404         if (!strcmp(var, "rebase.stat")) {
 405                 if (git_config_bool(var, value))
 406                         opts->flags |= REBASE_DIFFSTAT;
 407                 else
 408                         opts->flags &= !REBASE_DIFFSTAT;
 409                 return 0;
 410         }
 411
 412         return git_default_config(var, value, data);
 413 }
 414
 415 /*
 416  * Determines whether the commits in from..to are linear, i.e. contain
 417  * no merge commits. This function *expects* `from` to be an ancestor of
 418  * `to`.
 419  */
 420 static int is_linear_history(struct commit *from, struct commit *to)
 421 {
 422         while (to && to != from) {
 423                 parse_commit(to);
 424                 if (!to->parents)
 425                         return 1;
 426                 if (to->parents->next)
 427                         return 0;
 428                 to = to->parents->item;
 429         }
 430         return 1;
 431 }
 432
 433 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 434                             struct object_id *merge_base)
 435 {
 436         struct commit *head = lookup_commit(the_repository, head_oid);
 437         struct commit_list *merge_bases;
 438         int res;
 439
 440         if (!head)
 441                 return 0;
 442
 443         merge_bases = get_merge_bases(onto, head);
 444         if (merge_bases && !merge_bases->next) {
 445                 oidcpy(merge_base, &merge_bases->item->object.oid);
 446                 res = !oidcmp(merge_base, &onto->object.oid);
 447         } else {
 448                 oidcpy(merge_base, &null_oid);
 449                 res = 0;
 450         }
 451         free_commit_list(merge_bases);
 452         return res && is_linear_history(onto, head);
 453 }
 454
 455 /* -i followed by -m is still -i */
 456 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 457 {
 458         struct rebase_options *opts = opt->value;
 459
 460         if (!is_interactive(opts))
 461                 opts->type = REBASE_MERGE;
 462
 463         return 0;
 464 }
 465
 466 /* -i followed by -p is still explicitly interactive, but -p alone is not */
 467 static int parse_opt_interactive(const struct option *opt, const char *arg,
 468                                  int unset)
 469 {
 470         struct rebase_options *opts = opt->value;
 471
 472         opts->type = REBASE_INTERACTIVE;
 473         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 474
 475         return 0;
 476 }
 477
 478 int cmd_rebase(int argc, const char **argv, const char *prefix)
 479 {
 480         struct rebase_options options = {
 481                 .type = REBASE_UNSPECIFIED,
 482                 .flags = REBASE_NO_QUIET,
 483                 .git_am_opt = STRBUF_INIT,
 484         };
 485         const char *branch_name;
 486         int ret, flags, total_argc, in_progress = 0;
 487         int ok_to_skip_pre_rebase = 0;
 488         struct strbuf msg = STRBUF_INIT;
 489         struct strbuf revisions = STRBUF_INIT;
 490         struct strbuf buf = STRBUF_INIT;
 491         struct object_id merge_base;
 492         enum {
 493                 NO_ACTION,
 494                 ACTION_CONTINUE,
 495                 ACTION_SKIP,
 496                 ACTION_ABORT,
 497                 ACTION_QUIT,
 498                 ACTION_EDIT_TODO,
 499                 ACTION_SHOW_CURRENT_PATCH,
 500         } action = NO_ACTION;
 501         struct option builtin_rebase_options[] = {
 502                 OPT_STRING(0, "onto", &options.onto_name,
 503                            N_("revision"),
 504                            N_("rebase onto given branch instead of upstream")),
 505                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 506                          N_("allow pre-rebase hook to run")),
 507                 OPT_NEGBIT('q', "quiet", &options.flags,
 508                            N_("be quiet. implies --no-stat"),
 509                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 510                 OPT_BIT('v', "verbose", &options.flags,
 511                         N_("display a diffstat of what changed upstream"),
 512                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 513                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 514                         N_("do not show diffstat of what changed upstream"),
 515                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 516                 OPT_BIT('f', "force-rebase", &options.flags,
 517                         N_("cherry-pick all commits, even if unchanged"),
 518                         REBASE_FORCE),
 519                 OPT_BIT(0, "no-ff", &options.flags,
 520                         N_("cherry-pick all commits, even if unchanged"),
 521                         REBASE_FORCE),
 522                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
 523                             ACTION_CONTINUE),
 524                 OPT_CMDMODE(0, "skip", &action,
 525                             N_("skip current patch and continue"), ACTION_SKIP),
 526                 OPT_CMDMODE(0, "abort", &action,
 527                             N_("abort and check out the original branch"),
 528                             ACTION_ABORT),
 529                 OPT_CMDMODE(0, "quit", &action,
 530                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
 531                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
 532                             "during an interactive rebase"), ACTION_EDIT_TODO),
 533                 OPT_CMDMODE(0, "show-current-patch", &action,
 534                             N_("show the patch file being applied or merged"),
 535                             ACTION_SHOW_CURRENT_PATCH),
 536                 { OPTION_CALLBACK, 'm', "merge", &options, NULL,
 537                         N_("use merging strategies to rebase"),
 538                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 539                         parse_opt_merge },
 540                 { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
 541                         N_("let the user edit the list of commits to rebase"),
 542                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 543                         parse_opt_interactive },
 544                 OPT_SET_INT('p', "preserve-merges", &options.type,
 545                             N_("try to recreate merges instead of ignoring "
 546                                "them"), REBASE_PRESERVE_MERGES),
 547                 OPT_END(),
 548         };
 549
 550         /*
 551          * NEEDSWORK: Once the builtin rebase has been tested enough
 552          * and git-legacy-rebase.sh is retired to contrib/, this preamble
 553          * can be removed.
 554          */
 555
 556         if (!use_builtin_rebase()) {
 557                 const char *path = mkpath("%s/git-legacy-rebase",
 558                                           git_exec_path());
 559
 560                 if (sane_execvp(path, (char **)argv) < 0)
 561                         die_errno(_("could not exec %s"), path);
 562                 else
 563                         BUG("sane_execvp() returned???");
 564         }
 565
 566         if (argc == 2 && !strcmp(argv[1], "-h"))
 567                 usage_with_options(builtin_rebase_usage,
 568                                    builtin_rebase_options);
 569
 570         prefix = setup_git_directory();
 571         trace_repo_setup(prefix);
 572         setup_work_tree();
 573
 574         git_config(rebase_config, &options);
 575
 576         strbuf_reset(&buf);
 577         strbuf_addf(&buf, "%s/applying", apply_dir());
 578         if(file_exists(buf.buf))
 579                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
 580
 581         if (is_directory(apply_dir())) {
 582                 options.type = REBASE_AM;
 583                 options.state_dir = apply_dir();
 584         } else if (is_directory(merge_dir())) {
 585                 strbuf_reset(&buf);
 586                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
 587                 if (is_directory(buf.buf)) {
 588                         options.type = REBASE_PRESERVE_MERGES;
 589                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 590                 } else {
 591                         strbuf_reset(&buf);
 592                         strbuf_addf(&buf, "%s/interactive", merge_dir());
 593                         if(file_exists(buf.buf)) {
 594                                 options.type = REBASE_INTERACTIVE;
 595                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 596                         } else
 597                                 options.type = REBASE_MERGE;
 598                 }
 599                 options.state_dir = merge_dir();
 600         }
 601
 602         if (options.type != REBASE_UNSPECIFIED)
 603                 in_progress = 1;
 604
 605         total_argc = argc;
 606         argc = parse_options(argc, argv, prefix,
 607                              builtin_rebase_options,
 608                              builtin_rebase_usage, 0);
 609
 610         if (action != NO_ACTION && total_argc != 2) {
 611                 usage_with_options(builtin_rebase_usage,
 612                                    builtin_rebase_options);
 613         }
 614
 615         if (argc > 2)
 616                 usage_with_options(builtin_rebase_usage,
 617                                    builtin_rebase_options);
 618
 619         if (action != NO_ACTION && !in_progress)
 620                 die(_("No rebase in progress?"));
 621
 622         if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 623                 die(_("The --edit-todo action can only be used during "
 624                       "interactive rebase."));
 625
 626         switch (action) {
 627         case ACTION_CONTINUE: {
 628                 struct object_id head;
 629                 struct lock_file lock_file = LOCK_INIT;
 630                 int fd;
 631
 632                 options.action = "continue";
 633
 634                 /* Sanity check */
 635                 if (get_oid("HEAD", &head))
 636                         die(_("Cannot read HEAD"));
 637
 638                 fd = hold_locked_index(&lock_file, 0);
 639                 if (read_index(the_repository->index) < 0)
 640                         die(_("could not read index"));
 641                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 642                               NULL);
 643                 if (0 <= fd)
 644                         update_index_if_able(the_repository->index,
 645                                              &lock_file);
 646                 rollback_lock_file(&lock_file);
 647
 648                 if (has_unstaged_changes(1)) {
 649                         puts(_("You must edit all merge conflicts and then\n"
 650                                "mark them as resolved using git add"));
 651                         exit(1);
 652                 }
 653                 if (read_basic_state(&options))
 654                         exit(1);
 655                 goto run_rebase;
 656         }
 657         case ACTION_SKIP: {
 658                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
 659
 660                 options.action = "skip";
 661
 662                 rerere_clear(&merge_rr);
 663                 string_list_clear(&merge_rr, 1);
 664
 665                 if (reset_head(NULL, "reset", NULL, 0) < 0)
 666                         die(_("could not discard worktree changes"));
 667                 if (read_basic_state(&options))
 668                         exit(1);
 669                 goto run_rebase;
 670         }
 671         case ACTION_ABORT: {
 672                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
 673                 options.action = "abort";
 674
 675                 rerere_clear(&merge_rr);
 676                 string_list_clear(&merge_rr, 1);
 677
 678                 if (read_basic_state(&options))
 679                         exit(1);
 680                 if (reset_head(&options.orig_head, "reset",
 681                                options.head_name, 0) < 0)
 682                         die(_("could not move back to %s"),
 683                             oid_to_hex(&options.orig_head));
 684                 ret = finish_rebase(&options);
 685                 goto cleanup;
 686         }
 687         case ACTION_QUIT: {
 688                 strbuf_reset(&buf);
 689                 strbuf_addstr(&buf, options.state_dir);
 690                 ret = !!remove_dir_recursively(&buf, 0);
 691                 if (ret)
 692                         die(_("could not remove '%s'"), options.state_dir);
 693                 goto cleanup;
 694         }
 695         case ACTION_EDIT_TODO:
 696                 options.action = "edit-todo";
 697                 options.dont_finish_rebase = 1;
 698                 goto run_rebase;
 699         case ACTION_SHOW_CURRENT_PATCH:
 700                 options.action = "show-current-patch";
 701                 options.dont_finish_rebase = 1;
 702                 goto run_rebase;
 703         case NO_ACTION:
 704                 break;
 705         default:
 706                 BUG("action: %d", action);
 707         }
 708
 709         /* Make sure no rebase is in progress */
 710         if (in_progress) {
 711                 const char *last_slash = strrchr(options.state_dir, '/');
 712                 const char *state_dir_base =
 713                         last_slash ? last_slash + 1 : options.state_dir;
 714                 const char *cmd_live_rebase =
 715                         "git rebase (--continue | --abort | --skip)";
 716                 strbuf_reset(&buf);
 717                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
 718                 die(_("It seems that there is already a %s directory, and\n"
 719                       "I wonder if you are in the middle of another rebase.  "
 720                       "If that is the\n"
 721                       "case, please try\n\t%s\n"
 722                       "If that is not the case, please\n\t%s\n"
 723                       "and run me again.  I am stopping in case you still "
 724                       "have something\n"
 725                       "valuable there.\n"),
 726                     state_dir_base, cmd_live_rebase, buf.buf);
 727         }
 728
 729         if (!(options.flags & REBASE_NO_QUIET))
 730                 strbuf_addstr(&options.git_am_opt, " -q");
 731
 732         switch (options.type) {
 733         case REBASE_MERGE:
 734         case REBASE_INTERACTIVE:
 735         case REBASE_PRESERVE_MERGES:
 736                 options.state_dir = merge_dir();
 737                 break;
 738         case REBASE_AM:
 739                 options.state_dir = apply_dir();
 740                 break;
 741         default:
 742                 /* the default rebase backend is `--am` */
 743                 options.type = REBASE_AM;
 744                 options.state_dir = apply_dir();
 745                 break;
 746         }
 747
 748         if (!options.root) {
 749                 if (argc < 1)
 750                         die("TODO: handle @{upstream}");
 751                 else {
 752                         options.upstream_name = argv[0];
 753                         argc--;
 754                         argv++;
 755                         if (!strcmp(options.upstream_name, "-"))
 756                                 options.upstream_name = "@{-1}";
 757                 }
 758                 options.upstream = peel_committish(options.upstream_name);
 759                 if (!options.upstream)
 760                         die(_("invalid upstream '%s'"), options.upstream_name);
 761                 options.upstream_arg = options.upstream_name;
 762         } else
 763                 die("TODO: upstream for --root");
 764
 765         /* Make sure the branch to rebase onto is valid. */
 766         if (!options.onto_name)
 767                 options.onto_name = options.upstream_name;
 768         if (strstr(options.onto_name, "...")) {
 769                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
 770                         die(_("'%s': need exactly one merge base"),
 771                             options.onto_name);
 772                 options.onto = lookup_commit_or_die(&merge_base,
 773                                                     options.onto_name);
 774         } else {
 775                 options.onto = peel_committish(options.onto_name);
 776                 if (!options.onto)
 777                         die(_("Does not point to a valid commit '%s'"),
 778                                 options.onto_name);
 779         }
 780
 781         /*
 782          * If the branch to rebase is given, that is the branch we will rebase
 783          * branch_name -- branch/commit being rebased, or
 784          *                HEAD (already detached)
 785          * orig_head -- commit object name of tip of the branch before rebasing
 786          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
 787          */
 788         if (argc == 1) {
 789                 /* Is it "rebase other branchname" or "rebase other commit"? */
 790                 branch_name = argv[0];
 791                 options.switch_to = argv[0];
 792
 793                 /* Is it a local branch? */
 794                 strbuf_reset(&buf);
 795                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
 796                 if (!read_ref(buf.buf, &options.orig_head))
 797                         options.head_name = xstrdup(buf.buf);
 798                 /* If not is it a valid ref (branch or commit)? */
 799                 else if (!get_oid(branch_name, &options.orig_head))
 800                         options.head_name = NULL;
 801                 else
 802                         die(_("fatal: no such branch/commit '%s'"),
 803                             branch_name);
 804         } else if (argc == 0) {
 805                 /* Do not need to switch branches, we are already on it. */
 806                 options.head_name =
 807                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
 808                                          &flags));
 809                 if (!options.head_name)
 810                         die(_("No such ref: %s"), "HEAD");
 811                 if (flags & REF_ISSYMREF) {
 812                         if (!skip_prefix(options.head_name,
 813                                          "refs/heads/", &branch_name))
 814                                 branch_name = options.head_name;
 815
 816                 } else {
 817                         free(options.head_name);
 818                         options.head_name = NULL;
 819                         branch_name = "HEAD";
 820                 }
 821                 if (get_oid("HEAD", &options.orig_head))
 822                         die(_("Could not resolve HEAD to a revision"));
 823         } else
 824                 BUG("unexpected number of arguments left to parse");
 825
 826         if (read_index(the_repository->index) < 0)
 827                 die(_("could not read index"));
 828
 829         if (require_clean_work_tree("rebase",
 830                                     _("Please commit or stash them."), 1, 1)) {
 831                 ret = 1;
 832                 goto cleanup;
 833         }
 834
 835         /*
 836          * Now we are rebasing commits upstream..orig_head (or with --root,
 837          * everything leading up to orig_head) on top of onto.
 838          */
 839
 840         /*
 841          * Check if we are already based on onto with linear history,
 842          * but this should be done only when upstream and onto are the same
 843          * and if this is not an interactive rebase.
 844          */
 845         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
 846             !is_interactive(&options) && !options.restrict_revision &&
 847             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
 848                 int flag;
 849
 850                 if (!(options.flags & REBASE_FORCE)) {
 851                         /* Lazily switch to the target branch if needed... */
 852                         if (options.switch_to) {
 853                                 struct object_id oid;
 854
 855                                 if (get_oid(options.switch_to, &oid) < 0) {
 856                                         ret = !!error(_("could not parse '%s'"),
 857                                                       options.switch_to);
 858                                         goto cleanup;
 859                                 }
 860
 861                                 strbuf_reset(&buf);
 862                                 strbuf_addf(&buf, "rebase: checkout %s",
 863                                             options.switch_to);
 864                                 if (reset_head(&oid, "checkout",
 865                                                options.head_name, 0) < 0) {
 866                                         ret = !!error(_("could not switch to "
 867                                                         "%s"),
 868                                                       options.switch_to);
 869                                         goto cleanup;
 870                                 }
 871                         }
 872
 873                         if (!(options.flags & REBASE_NO_QUIET))
 874                                 ; /* be quiet */
 875                         else if (!strcmp(branch_name, "HEAD") &&
 876                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 877                                 puts(_("HEAD is up to date."));
 878                         else
 879                                 printf(_("Current branch %s is up to date.\n"),
 880                                        branch_name);
 881                         ret = !!finish_rebase(&options);
 882                         goto cleanup;
 883                 } else if (!(options.flags & REBASE_NO_QUIET))
 884                         ; /* be quiet */
 885                 else if (!strcmp(branch_name, "HEAD") &&
 886                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 887                         puts(_("HEAD is up to date, rebase forced."));
 888                 else
 889                         printf(_("Current branch %s is up to date, rebase "
 890                                  "forced.\n"), branch_name);
 891         }
 892
 893         /* If a hook exists, give it a chance to interrupt*/
 894         if (!ok_to_skip_pre_rebase &&
 895             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
 896                         argc ? argv[0] : NULL, NULL))
 897                 die(_("The pre-rebase hook refused to rebase."));
 898
 899         if (options.flags & REBASE_DIFFSTAT) {
 900                 struct diff_options opts;
 901
 902                 if (options.flags & REBASE_VERBOSE)
 903                         printf(_("Changes from %s to %s:\n"),
 904                                 oid_to_hex(&merge_base),
 905                                 oid_to_hex(&options.onto->object.oid));
 906
 907                 /* We want color (if set), but no pager */
 908                 diff_setup(&opts);
 909                 opts.stat_width = -1; /* use full terminal width */
 910                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
 911                 opts.output_format |=
 912                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 913                 opts.detect_rename = DIFF_DETECT_RENAME;
 914                 diff_setup_done(&opts);
 915                 diff_tree_oid(&merge_base, &options.onto->object.oid,
 916                               "", &opts);
 917                 diffcore_std(&opts);
 918                 diff_flush(&opts);
 919         }
 920
 921         if (is_interactive(&options))
 922                 goto run_rebase;
 923
 924         /* Detach HEAD and reset the tree */
 925         if (options.flags & REBASE_NO_QUIET)
 926                 printf(_("First, rewinding head to replay your work on top of "
 927                          "it...\n"));
 928
 929         strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
 930         if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
 931                 die(_("Could not detach HEAD"));
 932         strbuf_release(&msg);
 933
 934         strbuf_addf(&revisions, "%s..%s",
 935                     options.root ? oid_to_hex(&options.onto->object.oid) :
 936                     (options.restrict_revision ?
 937                      oid_to_hex(&options.restrict_revision->object.oid) :
 938                      oid_to_hex(&options.upstream->object.oid)),
 939                     oid_to_hex(&options.orig_head));
 940
 941         options.revisions = revisions.buf;
 942
 943 run_rebase:
 944         ret = !!run_specific_rebase(&options);
 945
 946 cleanup:
 947         strbuf_release(&revisions);
 948         free(options.head_name);
 949         return ret;
 950 }