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