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;
  53
  54         argv_array_pushl(&cp.args,
  55                          "config", "--bool", "rebase.usebuiltin", NULL);
  56         cp.git_cmd = 1;
  57         if (capture_command(&cp, &out, 6)) {
  58                 strbuf_release(&out);
  59                 return 1;
  60         }
  61
  62         strbuf_trim(&out);
  63         ret = !strcmp("true", out.buf);
  64         strbuf_release(&out);
  65         return ret;
  66 }
  67
  68 struct rebase_options {
  69         enum rebase_type type;
  70         const char *state_dir;
  71         struct commit *upstream;
  72         const char *upstream_name;
  73         const char *upstream_arg;
  74         char *head_name;
  75         struct object_id orig_head;
  76         struct commit *onto;
  77         const char *onto_name;
  78         const char *revisions;
  79         const char *switch_to;
  80         int root;
  81         struct object_id *squash_onto;
  82         struct commit *restrict_revision;
  83         int dont_finish_rebase;
  84         enum {
  85                 REBASE_NO_QUIET = 1<<0,
  86                 REBASE_VERBOSE = 1<<1,
  87                 REBASE_DIFFSTAT = 1<<2,
  88                 REBASE_FORCE = 1<<3,
  89                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  90         } flags;
  91         struct strbuf git_am_opt;
  92         const char *action;
  93         int signoff;
  94         int allow_rerere_autoupdate;
  95         int keep_empty;
  96         int autosquash;
  97         char *gpg_sign_opt;
  98         int autostash;
  99         char *cmd;
 100         int allow_empty_message;
 101         int rebase_merges, rebase_cousins;
 102         char *strategy, *strategy_opts;
 103         struct strbuf git_format_patch_opt;
 104 };
 105
 106 static int is_interactive(struct rebase_options *opts)
 107 {
 108         return opts->type == REBASE_INTERACTIVE ||
 109                 opts->type == REBASE_PRESERVE_MERGES;
 110 }
 111
 112 static void imply_interactive(struct rebase_options *opts, const char *option)
 113 {
 114         switch (opts->type) {
 115         case REBASE_AM:
 116                 die(_("%s requires an interactive rebase"), option);
 117                 break;
 118         case REBASE_INTERACTIVE:
 119         case REBASE_PRESERVE_MERGES:
 120                 break;
 121         case REBASE_MERGE:
 122                 /* we silently *upgrade* --merge to --interactive if needed */
 123         default:
 124                 opts->type = REBASE_INTERACTIVE; /* implied */
 125                 break;
 126         }
 127 }
 128
 129 /* Returns the filename prefixed by the state_dir */
 130 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 131 {
 132         static struct strbuf path = STRBUF_INIT;
 133         static size_t prefix_len;
 134
 135         if (!prefix_len) {
 136                 strbuf_addf(&path, "%s/", opts->state_dir);
 137                 prefix_len = path.len;
 138         }
 139
 140         strbuf_setlen(&path, prefix_len);
 141         strbuf_addstr(&path, filename);
 142         return path.buf;
 143 }
 144
 145 /* Read one file, then strip line endings */
 146 static int read_one(const char *path, struct strbuf *buf)
 147 {
 148         if (strbuf_read_file(buf, path, 0) < 0)
 149                 return error_errno(_("could not read '%s'"), path);
 150         strbuf_trim_trailing_newline(buf);
 151         return 0;
 152 }
 153
 154 /* Initialize the rebase options from the state directory. */
 155 static int read_basic_state(struct rebase_options *opts)
 156 {
 157         struct strbuf head_name = STRBUF_INIT;
 158         struct strbuf buf = STRBUF_INIT;
 159         struct object_id oid;
 160
 161         if (read_one(state_dir_path("head-name", opts), &head_name) ||
 162             read_one(state_dir_path("onto", opts), &buf))
 163                 return -1;
 164         opts->head_name = starts_with(head_name.buf, "refs/") ?
 165                 xstrdup(head_name.buf) : NULL;
 166         strbuf_release(&head_name);
 167         if (get_oid(buf.buf, &oid))
 168                 return error(_("could not get 'onto': '%s'"), buf.buf);
 169         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 170
 171         /*
 172          * We always write to orig-head, but interactive rebase used to write to
 173          * head. Fall back to reading from head to cover for the case that the
 174          * user upgraded git with an ongoing interactive rebase.
 175          */
 176         strbuf_reset(&buf);
 177         if (file_exists(state_dir_path("orig-head", opts))) {
 178                 if (read_one(state_dir_path("orig-head", opts), &buf))
 179                         return -1;
 180         } else if (read_one(state_dir_path("head", opts), &buf))
 181                 return -1;
 182         if (get_oid(buf.buf, &opts->orig_head))
 183                 return error(_("invalid orig-head: '%s'"), buf.buf);
 184
 185         strbuf_reset(&buf);
 186         if (read_one(state_dir_path("quiet", opts), &buf))
 187                 return -1;
 188         if (buf.len)
 189                 opts->flags &= ~REBASE_NO_QUIET;
 190         else
 191                 opts->flags |= REBASE_NO_QUIET;
 192
 193         if (file_exists(state_dir_path("verbose", opts)))
 194                 opts->flags |= REBASE_VERBOSE;
 195
 196         if (file_exists(state_dir_path("signoff", opts))) {
 197                 opts->signoff = 1;
 198                 opts->flags |= REBASE_FORCE;
 199         }
 200
 201         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 202                 strbuf_reset(&buf);
 203                 if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
 204                             &buf))
 205                         return -1;
 206                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
 207                         opts->allow_rerere_autoupdate = 1;
 208                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 209                         opts->allow_rerere_autoupdate = 0;
 210                 else
 211                         warning(_("ignoring invalid allow_rerere_autoupdate: "
 212                                   "'%s'"), buf.buf);
 213         } else
 214                 opts->allow_rerere_autoupdate = -1;
 215
 216         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 217                 strbuf_reset(&buf);
 218                 if (read_one(state_dir_path("gpg_sign_opt", opts),
 219                             &buf))
 220                         return -1;
 221                 free(opts->gpg_sign_opt);
 222                 opts->gpg_sign_opt = xstrdup(buf.buf);
 223         }
 224
 225         if (file_exists(state_dir_path("strategy", opts))) {
 226                 strbuf_reset(&buf);
 227                 if (read_one(state_dir_path("strategy", opts), &buf))
 228                         return -1;
 229                 free(opts->strategy);
 230                 opts->strategy = xstrdup(buf.buf);
 231         }
 232
 233         if (file_exists(state_dir_path("strategy_opts", opts))) {
 234                 strbuf_reset(&buf);
 235                 if (read_one(state_dir_path("strategy_opts", opts), &buf))
 236                         return -1;
 237                 free(opts->strategy_opts);
 238                 opts->strategy_opts = xstrdup(buf.buf);
 239         }
 240
 241         strbuf_release(&buf);
 242
 243         return 0;
 244 }
 245
 246 static int apply_autostash(struct rebase_options *opts)
 247 {
 248         const char *path = state_dir_path("autostash", opts);
 249         struct strbuf autostash = STRBUF_INIT;
 250         struct child_process stash_apply = CHILD_PROCESS_INIT;
 251
 252         if (!file_exists(path))
 253                 return 0;
 254
 255         if (read_one(path, &autostash))
 256                 return error(_("Could not read '%s'"), path);
 257         /* Ensure that the hash is not mistaken for a number */
 258         strbuf_addstr(&autostash, "^0");
 259         argv_array_pushl(&stash_apply.args,
 260                          "stash", "apply", autostash.buf, NULL);
 261         stash_apply.git_cmd = 1;
 262         stash_apply.no_stderr = stash_apply.no_stdout =
 263                 stash_apply.no_stdin = 1;
 264         if (!run_command(&stash_apply))
 265                 printf(_("Applied autostash.\n"));
 266         else {
 267                 struct argv_array args = ARGV_ARRAY_INIT;
 268                 int res = 0;
 269
 270                 argv_array_pushl(&args,
 271                                  "stash", "store", "-m", "autostash", "-q",
 272                                  autostash.buf, NULL);
 273                 if (run_command_v_opt(args.argv, RUN_GIT_CMD))
 274                         res = error(_("Cannot store %s"), autostash.buf);
 275                 argv_array_clear(&args);
 276                 strbuf_release(&autostash);
 277                 if (res)
 278                         return res;
 279
 280                 fprintf(stderr,
 281                         _("Applying autostash resulted in conflicts.\n"
 282                           "Your changes are safe in the stash.\n"
 283                           "You can run \"git stash pop\" or \"git stash drop\" "
 284                           "at any time.\n"));
 285         }
 286
 287         strbuf_release(&autostash);
 288         return 0;
 289 }
 290
 291 static int finish_rebase(struct rebase_options *opts)
 292 {
 293         struct strbuf dir = STRBUF_INIT;
 294         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 295
 296         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 297         apply_autostash(opts);
 298         close_all_packs(the_repository->objects);
 299         /*
 300          * We ignore errors in 'gc --auto', since the
 301          * user should see them.
 302          */
 303         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 304         strbuf_addstr(&dir, opts->state_dir);
 305         remove_dir_recursively(&dir, 0);
 306         strbuf_release(&dir);
 307
 308         return 0;
 309 }
 310
 311 static struct commit *peel_committish(const char *name)
 312 {
 313         struct object *obj;
 314         struct object_id oid;
 315
 316         if (get_oid(name, &oid))
 317                 return NULL;
 318         obj = parse_object(the_repository, &oid);
 319         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 320 }
 321
 322 static void add_var(struct strbuf *buf, const char *name, const char *value)
 323 {
 324         if (!value)
 325                 strbuf_addf(buf, "unset %s; ", name);
 326         else {
 327                 strbuf_addf(buf, "%s=", name);
 328                 sq_quote_buf(buf, value);
 329                 strbuf_addstr(buf, "; ");
 330         }
 331 }
 332
 333 static const char *resolvemsg =
 334 N_("Resolve all conflicts manually, mark them as resolved with\n"
 335 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 336 "You can instead skip this commit: run \"git rebase --skip\".\n"
 337 "To abort and get back to the state before \"git rebase\", run "
 338 "\"git rebase --abort\".");
 339
 340 static int run_specific_rebase(struct rebase_options *opts)
 341 {
 342         const char *argv[] = { NULL, NULL };
 343         struct strbuf script_snippet = STRBUF_INIT;
 344         int status;
 345         const char *backend, *backend_func;
 346
 347         if (opts->type == REBASE_INTERACTIVE) {
 348                 /* Run builtin interactive rebase */
 349                 struct child_process child = CHILD_PROCESS_INIT;
 350
 351                 argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
 352                                  resolvemsg);
 353                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 354                         argv_array_push(&child.env_array, "GIT_EDITOR=:");
 355                         opts->autosquash = 0;
 356                 }
 357
 358                 child.git_cmd = 1;
 359                 argv_array_push(&child.args, "rebase--interactive");
 360
 361                 if (opts->action)
 362                         argv_array_pushf(&child.args, "--%s", opts->action);
 363                 if (opts->keep_empty)
 364                         argv_array_push(&child.args, "--keep-empty");
 365                 if (opts->rebase_merges)
 366                         argv_array_push(&child.args, "--rebase-merges");
 367                 if (opts->rebase_cousins)
 368                         argv_array_push(&child.args, "--rebase-cousins");
 369                 if (opts->autosquash)
 370                         argv_array_push(&child.args, "--autosquash");
 371                 if (opts->flags & REBASE_VERBOSE)
 372                         argv_array_push(&child.args, "--verbose");
 373                 if (opts->flags & REBASE_FORCE)
 374                         argv_array_push(&child.args, "--no-ff");
 375                 if (opts->restrict_revision)
 376                         argv_array_pushf(&child.args,
 377                                          "--restrict-revision=^%s",
 378                                          oid_to_hex(&opts->restrict_revision->object.oid));
 379                 if (opts->upstream)
 380                         argv_array_pushf(&child.args, "--upstream=%s",
 381                                          oid_to_hex(&opts->upstream->object.oid));
 382                 if (opts->onto)
 383                         argv_array_pushf(&child.args, "--onto=%s",
 384                                          oid_to_hex(&opts->onto->object.oid));
 385                 if (opts->squash_onto)
 386                         argv_array_pushf(&child.args, "--squash-onto=%s",
 387                                          oid_to_hex(opts->squash_onto));
 388                 if (opts->onto_name)
 389                         argv_array_pushf(&child.args, "--onto-name=%s",
 390                                          opts->onto_name);
 391                 argv_array_pushf(&child.args, "--head-name=%s",
 392                                  opts->head_name ?
 393                                  opts->head_name : "detached HEAD");
 394                 if (opts->strategy)
 395                         argv_array_pushf(&child.args, "--strategy=%s",
 396                                          opts->strategy);
 397                 if (opts->strategy_opts)
 398                         argv_array_pushf(&child.args, "--strategy-opts=%s",
 399                                          opts->strategy_opts);
 400                 if (opts->switch_to)
 401                         argv_array_pushf(&child.args, "--switch-to=%s",
 402                                          opts->switch_to);
 403                 if (opts->cmd)
 404                         argv_array_pushf(&child.args, "--cmd=%s", opts->cmd);
 405                 if (opts->allow_empty_message)
 406                         argv_array_push(&child.args, "--allow-empty-message");
 407                 if (opts->allow_rerere_autoupdate > 0)
 408                         argv_array_push(&child.args, "--rerere-autoupdate");
 409                 else if (opts->allow_rerere_autoupdate == 0)
 410                         argv_array_push(&child.args, "--no-rerere-autoupdate");
 411                 if (opts->gpg_sign_opt)
 412                         argv_array_push(&child.args, opts->gpg_sign_opt);
 413                 if (opts->signoff)
 414                         argv_array_push(&child.args, "--signoff");
 415
 416                 status = run_command(&child);
 417                 goto finished_rebase;
 418         }
 419
 420         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 421         add_var(&script_snippet, "state_dir", opts->state_dir);
 422
 423         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 424         add_var(&script_snippet, "upstream", opts->upstream ?
 425                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 426         add_var(&script_snippet, "head_name",
 427                 opts->head_name ? opts->head_name : "detached HEAD");
 428         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 429         add_var(&script_snippet, "onto", opts->onto ?
 430                 oid_to_hex(&opts->onto->object.oid) : NULL);
 431         add_var(&script_snippet, "onto_name", opts->onto_name);
 432         add_var(&script_snippet, "revisions", opts->revisions);
 433         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 434                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 435         add_var(&script_snippet, "GIT_QUIET",
 436                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 437         add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 438         add_var(&script_snippet, "verbose",
 439                 opts->flags & REBASE_VERBOSE ? "t" : "");
 440         add_var(&script_snippet, "diffstat",
 441                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 442         add_var(&script_snippet, "force_rebase",
 443                 opts->flags & REBASE_FORCE ? "t" : "");
 444         if (opts->switch_to)
 445                 add_var(&script_snippet, "switch_to", opts->switch_to);
 446         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 447         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 448         add_var(&script_snippet, "allow_rerere_autoupdate",
 449                 opts->allow_rerere_autoupdate < 0 ? "" :
 450                 opts->allow_rerere_autoupdate ?
 451                 "--rerere-autoupdate" : "--no-rerere-autoupdate");
 452         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 453         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 454         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 455         add_var(&script_snippet, "cmd", opts->cmd);
 456         add_var(&script_snippet, "allow_empty_message",
 457                 opts->allow_empty_message ?  "--allow-empty-message" : "");
 458         add_var(&script_snippet, "rebase_merges",
 459                 opts->rebase_merges ? "t" : "");
 460         add_var(&script_snippet, "rebase_cousins",
 461                 opts->rebase_cousins ? "t" : "");
 462         add_var(&script_snippet, "strategy", opts->strategy);
 463         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
 464         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
 465         add_var(&script_snippet, "squash_onto",
 466                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
 467         add_var(&script_snippet, "git_format_patch_opt",
 468                 opts->git_format_patch_opt.buf);
 469
 470         if (is_interactive(opts) &&
 471             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 472                 strbuf_addstr(&script_snippet,
 473                               "GIT_EDITOR=:; export GIT_EDITOR; ");
 474                 opts->autosquash = 0;
 475         }
 476
 477         switch (opts->type) {
 478         case REBASE_AM:
 479                 backend = "git-rebase--am";
 480                 backend_func = "git_rebase__am";
 481                 break;
 482         case REBASE_MERGE:
 483                 backend = "git-rebase--merge";
 484                 backend_func = "git_rebase__merge";
 485                 break;
 486         case REBASE_PRESERVE_MERGES:
 487                 backend = "git-rebase--preserve-merges";
 488                 backend_func = "git_rebase__preserve_merges";
 489                 break;
 490         default:
 491                 BUG("Unhandled rebase type %d", opts->type);
 492                 break;
 493         }
 494
 495         strbuf_addf(&script_snippet,
 496                     ". git-sh-setup && . git-rebase--common &&"
 497                     " . %s && %s", backend, backend_func);
 498         argv[0] = script_snippet.buf;
 499
 500         status = run_command_v_opt(argv, RUN_USING_SHELL);
 501 finished_rebase:
 502         if (opts->dont_finish_rebase)
 503                 ; /* do nothing */
 504         else if (opts->type == REBASE_INTERACTIVE)
 505                 ; /* interactive rebase cleans up after itself */
 506         else if (status == 0) {
 507                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 508                         finish_rebase(opts);
 509         } else if (status == 2) {
 510                 struct strbuf dir = STRBUF_INIT;
 511
 512                 apply_autostash(opts);
 513                 strbuf_addstr(&dir, opts->state_dir);
 514                 remove_dir_recursively(&dir, 0);
 515                 strbuf_release(&dir);
 516                 die("Nothing to do");
 517         }
 518
 519         strbuf_release(&script_snippet);
 520
 521         return status ? -1 : 0;
 522 }
 523
 524 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 525
 526 #define RESET_HEAD_DETACH (1<<0)
 527 #define RESET_HEAD_HARD (1<<1)
 528
 529 static int reset_head(struct object_id *oid, const char *action,
 530                       const char *switch_to_branch, unsigned flags,
 531                       const char *reflog_orig_head, const char *reflog_head)
 532 {
 533         unsigned detach_head = flags & RESET_HEAD_DETACH;
 534         unsigned reset_hard = flags & RESET_HEAD_HARD;
 535         struct object_id head_oid;
 536         struct tree_desc desc[2] = { { NULL }, { NULL } };
 537         struct lock_file lock = LOCK_INIT;
 538         struct unpack_trees_options unpack_tree_opts;
 539         struct tree *tree;
 540         const char *reflog_action;
 541         struct strbuf msg = STRBUF_INIT;
 542         size_t prefix_len;
 543         struct object_id *orig = NULL, oid_orig,
 544                 *old_orig = NULL, oid_old_orig;
 545         int ret = 0, nr = 0;
 546
 547         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 548                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 549
 550         if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
 551                 ret = -1;
 552                 goto leave_reset_head;
 553         }
 554
 555         if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
 556                 ret = error(_("could not determine HEAD revision"));
 557                 goto leave_reset_head;
 558         }
 559
 560         if (!oid)
 561                 oid = &head_oid;
 562
 563         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 564         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 565         unpack_tree_opts.head_idx = 1;
 566         unpack_tree_opts.src_index = the_repository->index;
 567         unpack_tree_opts.dst_index = the_repository->index;
 568         unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
 569         unpack_tree_opts.update = 1;
 570         unpack_tree_opts.merge = 1;
 571         if (!detach_head)
 572                 unpack_tree_opts.reset = 1;
 573
 574         if (read_index_unmerged(the_repository->index) < 0) {
 575                 ret = error(_("could not read index"));
 576                 goto leave_reset_head;
 577         }
 578
 579         if (!reset_hard && !fill_tree_descriptor(&desc[nr++], &head_oid)) {
 580                 ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
 581                 goto leave_reset_head;
 582         }
 583
 584         if (!fill_tree_descriptor(&desc[nr++], oid)) {
 585                 ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
 586                 goto leave_reset_head;
 587         }
 588
 589         if (unpack_trees(nr, desc, &unpack_tree_opts)) {
 590                 ret = -1;
 591                 goto leave_reset_head;
 592         }
 593
 594         tree = parse_tree_indirect(oid);
 595         prime_cache_tree(the_repository->index, tree);
 596
 597         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
 598                 ret = error(_("could not write index"));
 599                 goto leave_reset_head;
 600         }
 601
 602         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 603         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 604         prefix_len = msg.len;
 605
 606         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 607                 old_orig = &oid_old_orig;
 608         if (!get_oid("HEAD", &oid_orig)) {
 609                 orig = &oid_orig;
 610                 if (!reflog_orig_head) {
 611                         strbuf_addstr(&msg, "updating ORIG_HEAD");
 612                         reflog_orig_head = msg.buf;
 613                 }
 614                 update_ref(reflog_orig_head, "ORIG_HEAD", orig, old_orig, 0,
 615                            UPDATE_REFS_MSG_ON_ERR);
 616         } else if (old_orig)
 617                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 618         if (!reflog_head) {
 619                 strbuf_setlen(&msg, prefix_len);
 620                 strbuf_addstr(&msg, "updating HEAD");
 621                 reflog_head = msg.buf;
 622         }
 623         if (!switch_to_branch)
 624                 ret = update_ref(reflog_head, "HEAD", oid, orig,
 625                                  detach_head ? REF_NO_DEREF : 0,
 626                                  UPDATE_REFS_MSG_ON_ERR);
 627         else {
 628                 ret = create_symref("HEAD", switch_to_branch, msg.buf);
 629                 if (!ret)
 630                         ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
 631                                          UPDATE_REFS_MSG_ON_ERR);
 632         }
 633
 634 leave_reset_head:
 635         strbuf_release(&msg);
 636         rollback_lock_file(&lock);
 637         while (nr)
 638                 free((void *)desc[--nr].buffer);
 639         return ret;
 640 }
 641
 642 static int rebase_config(const char *var, const char *value, void *data)
 643 {
 644         struct rebase_options *opts = data;
 645
 646         if (!strcmp(var, "rebase.stat")) {
 647                 if (git_config_bool(var, value))
 648                         opts->flags |= REBASE_DIFFSTAT;
 649                 else
 650                         opts->flags &= !REBASE_DIFFSTAT;
 651                 return 0;
 652         }
 653
 654         if (!strcmp(var, "rebase.autosquash")) {
 655                 opts->autosquash = git_config_bool(var, value);
 656                 return 0;
 657         }
 658
 659         if (!strcmp(var, "commit.gpgsign")) {
 660                 free(opts->gpg_sign_opt);
 661                 opts->gpg_sign_opt = git_config_bool(var, value) ?
 662                         xstrdup("-S") : NULL;
 663                 return 0;
 664         }
 665
 666         if (!strcmp(var, "rebase.autostash")) {
 667                 opts->autostash = git_config_bool(var, value);
 668                 return 0;
 669         }
 670
 671         return git_default_config(var, value, data);
 672 }
 673
 674 /*
 675  * Determines whether the commits in from..to are linear, i.e. contain
 676  * no merge commits. This function *expects* `from` to be an ancestor of
 677  * `to`.
 678  */
 679 static int is_linear_history(struct commit *from, struct commit *to)
 680 {
 681         while (to && to != from) {
 682                 parse_commit(to);
 683                 if (!to->parents)
 684                         return 1;
 685                 if (to->parents->next)
 686                         return 0;
 687                 to = to->parents->item;
 688         }
 689         return 1;
 690 }
 691
 692 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 693                             struct object_id *merge_base)
 694 {
 695         struct commit *head = lookup_commit(the_repository, head_oid);
 696         struct commit_list *merge_bases;
 697         int res;
 698
 699         if (!head)
 700                 return 0;
 701
 702         merge_bases = get_merge_bases(onto, head);
 703         if (merge_bases && !merge_bases->next) {
 704                 oidcpy(merge_base, &merge_bases->item->object.oid);
 705                 res = oideq(merge_base, &onto->object.oid);
 706         } else {
 707                 oidcpy(merge_base, &null_oid);
 708                 res = 0;
 709         }
 710         free_commit_list(merge_bases);
 711         return res && is_linear_history(onto, head);
 712 }
 713
 714 /* -i followed by -m is still -i */
 715 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 716 {
 717         struct rebase_options *opts = opt->value;
 718
 719         BUG_ON_OPT_NEG(unset);
 720         BUG_ON_OPT_ARG(arg);
 721
 722         if (!is_interactive(opts))
 723                 opts->type = REBASE_MERGE;
 724
 725         return 0;
 726 }
 727
 728 /* -i followed by -p is still explicitly interactive, but -p alone is not */
 729 static int parse_opt_interactive(const struct option *opt, const char *arg,
 730                                  int unset)
 731 {
 732         struct rebase_options *opts = opt->value;
 733
 734         BUG_ON_OPT_NEG(unset);
 735         BUG_ON_OPT_ARG(arg);
 736
 737         opts->type = REBASE_INTERACTIVE;
 738         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 739
 740         return 0;
 741 }
 742
 743 static void NORETURN error_on_missing_default_upstream(void)
 744 {
 745         struct branch *current_branch = branch_get(NULL);
 746
 747         printf(_("%s\n"
 748                  "Please specify which branch you want to rebase against.\n"
 749                  "See git-rebase(1) for details.\n"
 750                  "\n"
 751                  "    git rebase '<branch>'\n"
 752                  "\n"),
 753                 current_branch ? _("There is no tracking information for "
 754                         "the current branch.") :
 755                         _("You are not currently on a branch."));
 756
 757         if (current_branch) {
 758                 const char *remote = current_branch->remote_name;
 759
 760                 if (!remote)
 761                         remote = _("<remote>");
 762
 763                 printf(_("If you wish to set tracking information for this "
 764                          "branch you can do so with:\n"
 765                          "\n"
 766                          "    git branch --set-upstream-to=%s/<branch> %s\n"
 767                          "\n"),
 768                        remote, current_branch->name);
 769         }
 770         exit(1);
 771 }
 772
 773 int cmd_rebase(int argc, const char **argv, const char *prefix)
 774 {
 775         struct rebase_options options = {
 776                 .type = REBASE_UNSPECIFIED,
 777                 .flags = REBASE_NO_QUIET,
 778                 .git_am_opt = STRBUF_INIT,
 779                 .allow_rerere_autoupdate  = -1,
 780                 .allow_empty_message = 1,
 781                 .git_format_patch_opt = STRBUF_INIT,
 782         };
 783         const char *branch_name;
 784         int ret, flags, total_argc, in_progress = 0;
 785         int ok_to_skip_pre_rebase = 0;
 786         struct strbuf msg = STRBUF_INIT;
 787         struct strbuf revisions = STRBUF_INIT;
 788         struct strbuf buf = STRBUF_INIT;
 789         struct object_id merge_base;
 790         enum {
 791                 NO_ACTION,
 792                 ACTION_CONTINUE,
 793                 ACTION_SKIP,
 794                 ACTION_ABORT,
 795                 ACTION_QUIT,
 796                 ACTION_EDIT_TODO,
 797                 ACTION_SHOW_CURRENT_PATCH,
 798         } action = NO_ACTION;
 799         int committer_date_is_author_date = 0;
 800         int ignore_date = 0;
 801         int ignore_whitespace = 0;
 802         const char *gpg_sign = NULL;
 803         int opt_c = -1;
 804         struct string_list whitespace = STRING_LIST_INIT_NODUP;
 805         struct string_list exec = STRING_LIST_INIT_NODUP;
 806         const char *rebase_merges = NULL;
 807         int fork_point = -1;
 808         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
 809         struct object_id squash_onto;
 810         char *squash_onto_name = NULL;
 811         struct option builtin_rebase_options[] = {
 812                 OPT_STRING(0, "onto", &options.onto_name,
 813                            N_("revision"),
 814                            N_("rebase onto given branch instead of upstream")),
 815                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 816                          N_("allow pre-rebase hook to run")),
 817                 OPT_NEGBIT('q', "quiet", &options.flags,
 818                            N_("be quiet. implies --no-stat"),
 819                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 820                 OPT_BIT('v', "verbose", &options.flags,
 821                         N_("display a diffstat of what changed upstream"),
 822                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 823                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 824                         N_("do not show diffstat of what changed upstream"),
 825                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 826                 OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
 827                          N_("passed to 'git apply'")),
 828                 OPT_BOOL(0, "signoff", &options.signoff,
 829                          N_("add a Signed-off-by: line to each commit")),
 830                 OPT_BOOL(0, "committer-date-is-author-date",
 831                          &committer_date_is_author_date,
 832                          N_("passed to 'git am'")),
 833                 OPT_BOOL(0, "ignore-date", &ignore_date,
 834                          N_("passed to 'git am'")),
 835                 OPT_BIT('f', "force-rebase", &options.flags,
 836                         N_("cherry-pick all commits, even if unchanged"),
 837                         REBASE_FORCE),
 838                 OPT_BIT(0, "no-ff", &options.flags,
 839                         N_("cherry-pick all commits, even if unchanged"),
 840                         REBASE_FORCE),
 841                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
 842                             ACTION_CONTINUE),
 843                 OPT_CMDMODE(0, "skip", &action,
 844                             N_("skip current patch and continue"), ACTION_SKIP),
 845                 OPT_CMDMODE(0, "abort", &action,
 846                             N_("abort and check out the original branch"),
 847                             ACTION_ABORT),
 848                 OPT_CMDMODE(0, "quit", &action,
 849                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
 850                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
 851                             "during an interactive rebase"), ACTION_EDIT_TODO),
 852                 OPT_CMDMODE(0, "show-current-patch", &action,
 853                             N_("show the patch file being applied or merged"),
 854                             ACTION_SHOW_CURRENT_PATCH),
 855                 { OPTION_CALLBACK, 'm', "merge", &options, NULL,
 856                         N_("use merging strategies to rebase"),
 857                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 858                         parse_opt_merge },
 859                 { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
 860                         N_("let the user edit the list of commits to rebase"),
 861                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 862                         parse_opt_interactive },
 863                 OPT_SET_INT('p', "preserve-merges", &options.type,
 864                             N_("try to recreate merges instead of ignoring "
 865                                "them"), REBASE_PRESERVE_MERGES),
 866                 OPT_BOOL(0, "rerere-autoupdate",
 867                          &options.allow_rerere_autoupdate,
 868                          N_("allow rerere to update index  with resolved "
 869                             "conflict")),
 870                 OPT_BOOL('k', "keep-empty", &options.keep_empty,
 871                          N_("preserve empty commits during rebase")),
 872                 OPT_BOOL(0, "autosquash", &options.autosquash,
 873                          N_("move commits that begin with "
 874                             "squash!/fixup! under -i")),
 875                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 876                         N_("GPG-sign commits"),
 877                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 878                 OPT_STRING_LIST(0, "whitespace", &whitespace,
 879                                 N_("whitespace"), N_("passed to 'git apply'")),
 880                 OPT_SET_INT('C', NULL, &opt_c, N_("passed to 'git apply'"),
 881                             REBASE_AM),
 882                 OPT_BOOL(0, "autostash", &options.autostash,
 883                          N_("automatically stash/stash pop before and after")),
 884                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
 885                                 N_("add exec lines after each commit of the "
 886                                    "editable list")),
 887                 OPT_BOOL(0, "allow-empty-message",
 888                          &options.allow_empty_message,
 889                          N_("allow rebasing commits with empty messages")),
 890                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
 891                         N_("mode"),
 892                         N_("try to rebase merges instead of skipping them"),
 893                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
 894                 OPT_BOOL(0, "fork-point", &fork_point,
 895                          N_("use 'merge-base --fork-point' to refine upstream")),
 896                 OPT_STRING('s', "strategy", &options.strategy,
 897                            N_("strategy"), N_("use the given merge strategy")),
 898                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
 899                                 N_("option"),
 900                                 N_("pass the argument through to the merge "
 901                                    "strategy")),
 902                 OPT_BOOL(0, "root", &options.root,
 903                          N_("rebase all reachable commits up to the root(s)")),
 904                 OPT_END(),
 905         };
 906
 907         /*
 908          * NEEDSWORK: Once the builtin rebase has been tested enough
 909          * and git-legacy-rebase.sh is retired to contrib/, this preamble
 910          * can be removed.
 911          */
 912
 913         if (!use_builtin_rebase()) {
 914                 const char *path = mkpath("%s/git-legacy-rebase",
 915                                           git_exec_path());
 916
 917                 if (sane_execvp(path, (char **)argv) < 0)
 918                         die_errno(_("could not exec %s"), path);
 919                 else
 920                         BUG("sane_execvp() returned???");
 921         }
 922
 923         if (argc == 2 && !strcmp(argv[1], "-h"))
 924                 usage_with_options(builtin_rebase_usage,
 925                                    builtin_rebase_options);
 926
 927         prefix = setup_git_directory();
 928         trace_repo_setup(prefix);
 929         setup_work_tree();
 930
 931         git_config(rebase_config, &options);
 932
 933         strbuf_reset(&buf);
 934         strbuf_addf(&buf, "%s/applying", apply_dir());
 935         if(file_exists(buf.buf))
 936                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
 937
 938         if (is_directory(apply_dir())) {
 939                 options.type = REBASE_AM;
 940                 options.state_dir = apply_dir();
 941         } else if (is_directory(merge_dir())) {
 942                 strbuf_reset(&buf);
 943                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
 944                 if (is_directory(buf.buf)) {
 945                         options.type = REBASE_PRESERVE_MERGES;
 946                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 947                 } else {
 948                         strbuf_reset(&buf);
 949                         strbuf_addf(&buf, "%s/interactive", merge_dir());
 950                         if(file_exists(buf.buf)) {
 951                                 options.type = REBASE_INTERACTIVE;
 952                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 953                         } else
 954                                 options.type = REBASE_MERGE;
 955                 }
 956                 options.state_dir = merge_dir();
 957         }
 958
 959         if (options.type != REBASE_UNSPECIFIED)
 960                 in_progress = 1;
 961
 962         total_argc = argc;
 963         argc = parse_options(argc, argv, prefix,
 964                              builtin_rebase_options,
 965                              builtin_rebase_usage, 0);
 966
 967         if (action != NO_ACTION && total_argc != 2) {
 968                 usage_with_options(builtin_rebase_usage,
 969                                    builtin_rebase_options);
 970         }
 971
 972         if (argc > 2)
 973                 usage_with_options(builtin_rebase_usage,
 974                                    builtin_rebase_options);
 975
 976         if (action != NO_ACTION && !in_progress)
 977                 die(_("No rebase in progress?"));
 978
 979         if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 980                 die(_("The --edit-todo action can only be used during "
 981                       "interactive rebase."));
 982
 983         switch (action) {
 984         case ACTION_CONTINUE: {
 985                 struct object_id head;
 986                 struct lock_file lock_file = LOCK_INIT;
 987                 int fd;
 988
 989                 options.action = "continue";
 990
 991                 /* Sanity check */
 992                 if (get_oid("HEAD", &head))
 993                         die(_("Cannot read HEAD"));
 994
 995                 fd = hold_locked_index(&lock_file, 0);
 996                 if (read_index(the_repository->index) < 0)
 997                         die(_("could not read index"));
 998                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 999                               NULL);
1000                 if (0 <= fd)
1001                         update_index_if_able(the_repository->index,
1002                                              &lock_file);
1003                 rollback_lock_file(&lock_file);
1004
1005                 if (has_unstaged_changes(1)) {
1006                         puts(_("You must edit all merge conflicts and then\n"
1007                                "mark them as resolved using git add"));
1008                         exit(1);
1009                 }
1010                 if (read_basic_state(&options))
1011                         exit(1);
1012                 goto run_rebase;
1013         }
1014         case ACTION_SKIP: {
1015                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1016
1017                 options.action = "skip";
1018
1019                 rerere_clear(&merge_rr);
1020                 string_list_clear(&merge_rr, 1);
1021
1022                 if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
1023                                NULL, NULL) < 0)
1024                         die(_("could not discard worktree changes"));
1025                 remove_branch_state();
1026                 if (read_basic_state(&options))
1027                         exit(1);
1028                 goto run_rebase;
1029         }
1030         case ACTION_ABORT: {
1031                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1032                 options.action = "abort";
1033
1034                 rerere_clear(&merge_rr);
1035                 string_list_clear(&merge_rr, 1);
1036
1037                 if (read_basic_state(&options))
1038                         exit(1);
1039                 if (reset_head(&options.orig_head, "reset",
1040                                options.head_name, RESET_HEAD_HARD,
1041                                NULL, NULL) < 0)
1042                         die(_("could not move back to %s"),
1043                             oid_to_hex(&options.orig_head));
1044                 remove_branch_state();
1045                 ret = finish_rebase(&options);
1046                 goto cleanup;
1047         }
1048         case ACTION_QUIT: {
1049                 strbuf_reset(&buf);
1050                 strbuf_addstr(&buf, options.state_dir);
1051                 ret = !!remove_dir_recursively(&buf, 0);
1052                 if (ret)
1053                         die(_("could not remove '%s'"), options.state_dir);
1054                 goto cleanup;
1055         }
1056         case ACTION_EDIT_TODO:
1057                 options.action = "edit-todo";
1058                 options.dont_finish_rebase = 1;
1059                 goto run_rebase;
1060         case ACTION_SHOW_CURRENT_PATCH:
1061                 options.action = "show-current-patch";
1062                 options.dont_finish_rebase = 1;
1063                 goto run_rebase;
1064         case NO_ACTION:
1065                 break;
1066         default:
1067                 BUG("action: %d", action);
1068         }
1069
1070         /* Make sure no rebase is in progress */
1071         if (in_progress) {
1072                 const char *last_slash = strrchr(options.state_dir, '/');
1073                 const char *state_dir_base =
1074                         last_slash ? last_slash + 1 : options.state_dir;
1075                 const char *cmd_live_rebase =
1076                         "git rebase (--continue | --abort | --skip)";
1077                 strbuf_reset(&buf);
1078                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1079                 die(_("It seems that there is already a %s directory, and\n"
1080                       "I wonder if you are in the middle of another rebase.  "
1081                       "If that is the\n"
1082                       "case, please try\n\t%s\n"
1083                       "If that is not the case, please\n\t%s\n"
1084                       "and run me again.  I am stopping in case you still "
1085                       "have something\n"
1086                       "valuable there.\n"),
1087                     state_dir_base, cmd_live_rebase, buf.buf);
1088         }
1089
1090         if (!(options.flags & REBASE_NO_QUIET))
1091                 strbuf_addstr(&options.git_am_opt, " -q");
1092
1093         if (committer_date_is_author_date) {
1094                 strbuf_addstr(&options.git_am_opt,
1095                               " --committer-date-is-author-date");
1096                 options.flags |= REBASE_FORCE;
1097         }
1098
1099         if (ignore_whitespace)
1100                 strbuf_addstr(&options.git_am_opt, " --ignore-whitespace");
1101
1102         if (ignore_date) {
1103                 strbuf_addstr(&options.git_am_opt, " --ignore-date");
1104                 options.flags |= REBASE_FORCE;
1105         }
1106
1107         if (options.keep_empty)
1108                 imply_interactive(&options, "--keep-empty");
1109
1110         if (gpg_sign) {
1111                 free(options.gpg_sign_opt);
1112                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1113         }
1114
1115         if (opt_c >= 0)
1116                 strbuf_addf(&options.git_am_opt, " -C%d", opt_c);
1117
1118         if (whitespace.nr) {
1119                 int i;
1120
1121                 for (i = 0; i < whitespace.nr; i++) {
1122                         const char *item = whitespace.items[i].string;
1123
1124                         strbuf_addf(&options.git_am_opt, " --whitespace=%s",
1125                                     item);
1126
1127                         if ((!strcmp(item, "fix")) || (!strcmp(item, "strip")))
1128                                 options.flags |= REBASE_FORCE;
1129                 }
1130         }
1131
1132         if (exec.nr) {
1133                 int i;
1134
1135                 imply_interactive(&options, "--exec");
1136
1137                 strbuf_reset(&buf);
1138                 for (i = 0; i < exec.nr; i++)
1139                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1140                 options.cmd = xstrdup(buf.buf);
1141         }
1142
1143         if (rebase_merges) {
1144                 if (!*rebase_merges)
1145                         ; /* default mode; do nothing */
1146                 else if (!strcmp("rebase-cousins", rebase_merges))
1147                         options.rebase_cousins = 1;
1148                 else if (strcmp("no-rebase-cousins", rebase_merges))
1149                         die(_("Unknown mode: %s"), rebase_merges);
1150                 options.rebase_merges = 1;
1151                 imply_interactive(&options, "--rebase-merges");
1152         }
1153
1154         if (strategy_options.nr) {
1155                 int i;
1156
1157                 if (!options.strategy)
1158                         options.strategy = "recursive";
1159
1160                 strbuf_reset(&buf);
1161                 for (i = 0; i < strategy_options.nr; i++)
1162                         strbuf_addf(&buf, " --%s",
1163                                     strategy_options.items[i].string);
1164                 options.strategy_opts = xstrdup(buf.buf);
1165         }
1166
1167         if (options.strategy) {
1168                 options.strategy = xstrdup(options.strategy);
1169                 switch (options.type) {
1170                 case REBASE_AM:
1171                         die(_("--strategy requires --merge or --interactive"));
1172                 case REBASE_MERGE:
1173                 case REBASE_INTERACTIVE:
1174                 case REBASE_PRESERVE_MERGES:
1175                         /* compatible */
1176                         break;
1177                 case REBASE_UNSPECIFIED:
1178                         options.type = REBASE_MERGE;
1179                         break;
1180                 default:
1181                         BUG("unhandled rebase type (%d)", options.type);
1182                 }
1183         }
1184
1185         if (options.root && !options.onto_name)
1186                 imply_interactive(&options, "--root without --onto");
1187
1188         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1189                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1190
1191         switch (options.type) {
1192         case REBASE_MERGE:
1193         case REBASE_INTERACTIVE:
1194         case REBASE_PRESERVE_MERGES:
1195                 options.state_dir = merge_dir();
1196                 break;
1197         case REBASE_AM:
1198                 options.state_dir = apply_dir();
1199                 break;
1200         default:
1201                 /* the default rebase backend is `--am` */
1202                 options.type = REBASE_AM;
1203                 options.state_dir = apply_dir();
1204                 break;
1205         }
1206
1207         if (options.git_am_opt.len) {
1208                 const char *p;
1209
1210                 /* all am options except -q are compatible only with --am */
1211                 strbuf_reset(&buf);
1212                 strbuf_addbuf(&buf, &options.git_am_opt);
1213                 strbuf_addch(&buf, ' ');
1214                 while ((p = strstr(buf.buf, " -q ")))
1215                         strbuf_splice(&buf, p - buf.buf, 4, " ", 1);
1216                 strbuf_trim(&buf);
1217
1218                 if (is_interactive(&options) && buf.len)
1219                         die(_("error: cannot combine interactive options "
1220                               "(--interactive, --exec, --rebase-merges, "
1221                               "--preserve-merges, --keep-empty, --root + "
1222                               "--onto) with am options (%s)"), buf.buf);
1223                 if (options.type == REBASE_MERGE && buf.len)
1224                         die(_("error: cannot combine merge options (--merge, "
1225                               "--strategy, --strategy-option) with am options "
1226                               "(%s)"), buf.buf);
1227         }
1228
1229         if (options.signoff) {
1230                 if (options.type == REBASE_PRESERVE_MERGES)
1231                         die("cannot combine '--signoff' with "
1232                             "'--preserve-merges'");
1233                 strbuf_addstr(&options.git_am_opt, " --signoff");
1234                 options.flags |= REBASE_FORCE;
1235         }
1236
1237         if (options.type == REBASE_PRESERVE_MERGES)
1238                 /*
1239                  * Note: incompatibility with --signoff handled in signoff block above
1240                  * Note: incompatibility with --interactive is just a strong warning;
1241                  *       git-rebase.txt caveats with "unless you know what you are doing"
1242                  */
1243                 if (options.rebase_merges)
1244                         die(_("error: cannot combine '--preserve-merges' with "
1245                               "'--rebase-merges'"));
1246
1247         if (options.rebase_merges) {
1248                 if (strategy_options.nr)
1249                         die(_("error: cannot combine '--rebase-merges' with "
1250                               "'--strategy-option'"));
1251                 if (options.strategy)
1252                         die(_("error: cannot combine '--rebase-merges' with "
1253                               "'--strategy'"));
1254         }
1255
1256         if (!options.root) {
1257                 if (argc < 1) {
1258                         struct branch *branch;
1259
1260                         branch = branch_get(NULL);
1261                         options.upstream_name = branch_get_upstream(branch,
1262                                                                     NULL);
1263                         if (!options.upstream_name)
1264                                 error_on_missing_default_upstream();
1265                         if (fork_point < 0)
1266                                 fork_point = 1;
1267                 } else {
1268                         options.upstream_name = argv[0];
1269                         argc--;
1270                         argv++;
1271                         if (!strcmp(options.upstream_name, "-"))
1272                                 options.upstream_name = "@{-1}";
1273                 }
1274                 options.upstream = peel_committish(options.upstream_name);
1275                 if (!options.upstream)
1276                         die(_("invalid upstream '%s'"), options.upstream_name);
1277                 options.upstream_arg = options.upstream_name;
1278         } else {
1279                 if (!options.onto_name) {
1280                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1281                                         &squash_onto, NULL, NULL) < 0)
1282                                 die(_("Could not create new root commit"));
1283                         options.squash_onto = &squash_onto;
1284                         options.onto_name = squash_onto_name =
1285                                 xstrdup(oid_to_hex(&squash_onto));
1286                 }
1287                 options.upstream_name = NULL;
1288                 options.upstream = NULL;
1289                 if (argc > 1)
1290                         usage_with_options(builtin_rebase_usage,
1291                                            builtin_rebase_options);
1292                 options.upstream_arg = "--root";
1293         }
1294
1295         /* Make sure the branch to rebase onto is valid. */
1296         if (!options.onto_name)
1297                 options.onto_name = options.upstream_name;
1298         if (strstr(options.onto_name, "...")) {
1299                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
1300                         die(_("'%s': need exactly one merge base"),
1301                             options.onto_name);
1302                 options.onto = lookup_commit_or_die(&merge_base,
1303                                                     options.onto_name);
1304         } else {
1305                 options.onto = peel_committish(options.onto_name);
1306                 if (!options.onto)
1307                         die(_("Does not point to a valid commit '%s'"),
1308                                 options.onto_name);
1309         }
1310
1311         /*
1312          * If the branch to rebase is given, that is the branch we will rebase
1313          * branch_name -- branch/commit being rebased, or
1314          *                HEAD (already detached)
1315          * orig_head -- commit object name of tip of the branch before rebasing
1316          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1317          */
1318         if (argc == 1) {
1319                 /* Is it "rebase other branchname" or "rebase other commit"? */
1320                 branch_name = argv[0];
1321                 options.switch_to = argv[0];
1322
1323                 /* Is it a local branch? */
1324                 strbuf_reset(&buf);
1325                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1326                 if (!read_ref(buf.buf, &options.orig_head))
1327                         options.head_name = xstrdup(buf.buf);
1328                 /* If not is it a valid ref (branch or commit)? */
1329                 else if (!get_oid(branch_name, &options.orig_head))
1330                         options.head_name = NULL;
1331                 else
1332                         die(_("fatal: no such branch/commit '%s'"),
1333                             branch_name);
1334         } else if (argc == 0) {
1335                 /* Do not need to switch branches, we are already on it. */
1336                 options.head_name =
1337                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1338                                          &flags));
1339                 if (!options.head_name)
1340                         die(_("No such ref: %s"), "HEAD");
1341                 if (flags & REF_ISSYMREF) {
1342                         if (!skip_prefix(options.head_name,
1343                                          "refs/heads/", &branch_name))
1344                                 branch_name = options.head_name;
1345
1346                 } else {
1347                         free(options.head_name);
1348                         options.head_name = NULL;
1349                         branch_name = "HEAD";
1350                 }
1351                 if (get_oid("HEAD", &options.orig_head))
1352                         die(_("Could not resolve HEAD to a revision"));
1353         } else
1354                 BUG("unexpected number of arguments left to parse");
1355
1356         if (fork_point > 0) {
1357                 struct commit *head =
1358                         lookup_commit_reference(the_repository,
1359                                                 &options.orig_head);
1360                 options.restrict_revision =
1361                         get_fork_point(options.upstream_name, head);
1362         }
1363
1364         if (read_index(the_repository->index) < 0)
1365                 die(_("could not read index"));
1366
1367         if (options.autostash) {
1368                 struct lock_file lock_file = LOCK_INIT;
1369                 int fd;
1370
1371                 fd = hold_locked_index(&lock_file, 0);
1372                 refresh_cache(REFRESH_QUIET);
1373                 if (0 <= fd)
1374                         update_index_if_able(&the_index, &lock_file);
1375                 rollback_lock_file(&lock_file);
1376
1377                 if (has_unstaged_changes(1) || has_uncommitted_changes(1)) {
1378                         const char *autostash =
1379                                 state_dir_path("autostash", &options);
1380                         struct child_process stash = CHILD_PROCESS_INIT;
1381                         struct object_id oid;
1382                         struct commit *head =
1383                                 lookup_commit_reference(the_repository,
1384                                                         &options.orig_head);
1385
1386                         argv_array_pushl(&stash.args,
1387                                          "stash", "create", "autostash", NULL);
1388                         stash.git_cmd = 1;
1389                         stash.no_stdin = 1;
1390                         strbuf_reset(&buf);
1391                         if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
1392                                 die(_("Cannot autostash"));
1393                         strbuf_trim_trailing_newline(&buf);
1394                         if (get_oid(buf.buf, &oid))
1395                                 die(_("Unexpected stash response: '%s'"),
1396                                     buf.buf);
1397                         strbuf_reset(&buf);
1398                         strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
1399
1400                         if (safe_create_leading_directories_const(autostash))
1401                                 die(_("Could not create directory for '%s'"),
1402                                     options.state_dir);
1403                         write_file(autostash, "%s", oid_to_hex(&oid));
1404                         printf(_("Created autostash: %s\n"), buf.buf);
1405                         if (reset_head(&head->object.oid, "reset --hard",
1406                                        NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
1407                                 die(_("could not reset --hard"));
1408                         printf(_("HEAD is now at %s"),
1409                                find_unique_abbrev(&head->object.oid,
1410                                                   DEFAULT_ABBREV));
1411                         strbuf_reset(&buf);
1412                         pp_commit_easy(CMIT_FMT_ONELINE, head, &buf);
1413                         if (buf.len > 0)
1414                                 printf(" %s", buf.buf);
1415                         putchar('\n');
1416
1417                         if (discard_index(the_repository->index) < 0 ||
1418                                 read_index(the_repository->index) < 0)
1419                                 die(_("could not read index"));
1420                 }
1421         }
1422
1423         if (require_clean_work_tree("rebase",
1424                                     _("Please commit or stash them."), 1, 1)) {
1425                 ret = 1;
1426                 goto cleanup;
1427         }
1428
1429         /*
1430          * Now we are rebasing commits upstream..orig_head (or with --root,
1431          * everything leading up to orig_head) on top of onto.
1432          */
1433
1434         /*
1435          * Check if we are already based on onto with linear history,
1436          * but this should be done only when upstream and onto are the same
1437          * and if this is not an interactive rebase.
1438          */
1439         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
1440             !is_interactive(&options) && !options.restrict_revision &&
1441             options.upstream &&
1442             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
1443                 int flag;
1444
1445                 if (!(options.flags & REBASE_FORCE)) {
1446                         /* Lazily switch to the target branch if needed... */
1447                         if (options.switch_to) {
1448                                 struct object_id oid;
1449
1450                                 if (get_oid(options.switch_to, &oid) < 0) {
1451                                         ret = !!error(_("could not parse '%s'"),
1452                                                       options.switch_to);
1453                                         goto cleanup;
1454                                 }
1455
1456                                 strbuf_reset(&buf);
1457                                 strbuf_addf(&buf, "rebase: checkout %s",
1458                                             options.switch_to);
1459                                 if (reset_head(&oid, "checkout",
1460                                                options.head_name, 0,
1461                                                NULL, NULL) < 0) {
1462                                         ret = !!error(_("could not switch to "
1463                                                         "%s"),
1464                                                       options.switch_to);
1465                                         goto cleanup;
1466                                 }
1467                         }
1468
1469                         if (!(options.flags & REBASE_NO_QUIET))
1470                                 ; /* be quiet */
1471                         else if (!strcmp(branch_name, "HEAD") &&
1472                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1473                                 puts(_("HEAD is up to date."));
1474                         else
1475                                 printf(_("Current branch %s is up to date.\n"),
1476                                        branch_name);
1477                         ret = !!finish_rebase(&options);
1478                         goto cleanup;
1479                 } else if (!(options.flags & REBASE_NO_QUIET))
1480                         ; /* be quiet */
1481                 else if (!strcmp(branch_name, "HEAD") &&
1482                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1483                         puts(_("HEAD is up to date, rebase forced."));
1484                 else
1485                         printf(_("Current branch %s is up to date, rebase "
1486                                  "forced.\n"), branch_name);
1487         }
1488
1489         /* If a hook exists, give it a chance to interrupt*/
1490         if (!ok_to_skip_pre_rebase &&
1491             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
1492                         argc ? argv[0] : NULL, NULL))
1493                 die(_("The pre-rebase hook refused to rebase."));
1494
1495         if (options.flags & REBASE_DIFFSTAT) {
1496                 struct diff_options opts;
1497
1498                 if (options.flags & REBASE_VERBOSE)
1499                         printf(_("Changes from %s to %s:\n"),
1500                                 oid_to_hex(&merge_base),
1501                                 oid_to_hex(&options.onto->object.oid));
1502
1503                 /* We want color (if set), but no pager */
1504                 diff_setup(&opts);
1505                 opts.stat_width = -1; /* use full terminal width */
1506                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
1507                 opts.output_format |=
1508                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
1509                 opts.detect_rename = DIFF_DETECT_RENAME;
1510                 diff_setup_done(&opts);
1511                 diff_tree_oid(&merge_base, &options.onto->object.oid,
1512                               "", &opts);
1513                 diffcore_std(&opts);
1514                 diff_flush(&opts);
1515         }
1516
1517         if (is_interactive(&options))
1518                 goto run_rebase;
1519
1520         /* Detach HEAD and reset the tree */
1521         if (options.flags & REBASE_NO_QUIET)
1522                 printf(_("First, rewinding head to replay your work on top of "
1523                          "it...\n"));
1524
1525         strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
1526         if (reset_head(&options.onto->object.oid, "checkout", NULL,
1527                        RESET_HEAD_DETACH, NULL, msg.buf))
1528                 die(_("Could not detach HEAD"));
1529         strbuf_release(&msg);
1530
1531         /*
1532          * If the onto is a proper descendant of the tip of the branch, then
1533          * we just fast-forwarded.
1534          */
1535         strbuf_reset(&msg);
1536         if (!oidcmp(&merge_base, &options.orig_head)) {
1537                 printf(_("Fast-forwarded %s to %s. \n"),
1538                         branch_name, options.onto_name);
1539                 strbuf_addf(&msg, "rebase finished: %s onto %s",
1540                         options.head_name ? options.head_name : "detached HEAD",
1541                         oid_to_hex(&options.onto->object.oid));
1542                 reset_head(NULL, "Fast-forwarded", options.head_name, 0,
1543                            "HEAD", msg.buf);
1544                 strbuf_release(&msg);
1545                 ret = !!finish_rebase(&options);
1546                 goto cleanup;
1547         }
1548
1549         strbuf_addf(&revisions, "%s..%s",
1550                     options.root ? oid_to_hex(&options.onto->object.oid) :
1551                     (options.restrict_revision ?
1552                      oid_to_hex(&options.restrict_revision->object.oid) :
1553                      oid_to_hex(&options.upstream->object.oid)),
1554                     oid_to_hex(&options.orig_head));
1555
1556         options.revisions = revisions.buf;
1557
1558 run_rebase:
1559         ret = !!run_specific_rebase(&options);
1560
1561 cleanup:
1562         strbuf_release(&revisions);
1563         free(options.head_name);
1564         free(options.gpg_sign_opt);
1565         free(options.cmd);
1566         free(squash_onto_name);
1567         return ret;
1568 }