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