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