builtin/rebase.c

   1 /*
   2  * "git rebase" builtin command
   3  *
   4  * Copyright (c) 2018 Pratik Karki
   5  */
   6
   7 #include "builtin.h"
   8 #include "run-command.h"
   9 #include "exec-cmd.h"
  10 #include "argv-array.h"
  11 #include "dir.h"
  12 #include "packfile.h"
  13 #include "refs.h"
  14 #include "quote.h"
  15 #include "config.h"
  16 #include "cache-tree.h"
  17 #include "unpack-trees.h"
  18 #include "lockfile.h"
  19 #include "parse-options.h"
  20 #include "commit.h"
  21 #include "diff.h"
  22 #include "wt-status.h"
  23 #include "revision.h"
  24 #include "commit-reach.h"
  25 #include "rerere.h"
  26
  27 static char const * const builtin_rebase_usage[] = {
  28         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  29                 "[<upstream>] [<branch>]"),
  30         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  31                 "--root [<branch>]"),
  32         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  33         NULL
  34 };
  35
  36 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  37 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  38
  39 enum rebase_type {
  40         REBASE_UNSPECIFIED = -1,
  41         REBASE_AM,
  42         REBASE_MERGE,
  43         REBASE_INTERACTIVE,
  44         REBASE_PRESERVE_MERGES
  45 };
  46
  47 static int use_builtin_rebase(void)
  48 {
  49         struct child_process cp = CHILD_PROCESS_INIT;
  50         struct strbuf out = STRBUF_INIT;
  51         int ret;
  52
  53         argv_array_pushl(&cp.args,
  54                          "config", "--bool", "rebase.usebuiltin", NULL);
  55         cp.git_cmd = 1;
  56         if (capture_command(&cp, &out, 6)) {
  57                 strbuf_release(&out);
  58                 return 1;
  59         }
  60
  61         strbuf_trim(&out);
  62         ret = !strcmp("true", out.buf);
  63         strbuf_release(&out);
  64         return ret;
  65 }
  66
  67 struct rebase_options {
  68         enum rebase_type type;
  69         const char *state_dir;
  70         struct commit *upstream;
  71         const char *upstream_name;
  72         const char *upstream_arg;
  73         char *head_name;
  74         struct object_id orig_head;
  75         struct commit *onto;
  76         const char *onto_name;
  77         const char *revisions;
  78         const char *switch_to;
  79         int root;
  80         struct object_id *squash_onto;
  81         struct commit *restrict_revision;
  82         int dont_finish_rebase;
  83         enum {
  84                 REBASE_NO_QUIET = 1<<0,
  85                 REBASE_VERBOSE = 1<<1,
  86                 REBASE_DIFFSTAT = 1<<2,
  87                 REBASE_FORCE = 1<<3,
  88                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  89         } flags;
  90         struct strbuf git_am_opt;
  91         const char *action;
  92         int signoff;
  93         int allow_rerere_autoupdate;
  94         int keep_empty;
  95         int autosquash;
  96         char *gpg_sign_opt;
  97         int autostash;
  98         char *cmd;
  99         int allow_empty_message;
 100         int rebase_merges, rebase_cousins;
 101         char *strategy, *strategy_opts;
 102         struct strbuf git_format_patch_opt;
 103 };
 104
 105 static int is_interactive(struct rebase_options *opts)
 106 {
 107         return opts->type == REBASE_INTERACTIVE ||
 108                 opts->type == REBASE_PRESERVE_MERGES;
 109 }
 110
 111 static void imply_interactive(struct rebase_options *opts, const char *option)
 112 {
 113         switch (opts->type) {
 114         case REBASE_AM:
 115                 die(_("%s requires an interactive rebase"), option);
 116                 break;
 117         case REBASE_INTERACTIVE:
 118         case REBASE_PRESERVE_MERGES:
 119                 break;
 120         case REBASE_MERGE:
 121                 /* we silently *upgrade* --merge to --interactive if needed */
 122         default:
 123                 opts->type = REBASE_INTERACTIVE; /* implied */
 124                 break;
 125         }
 126 }
 127
 128 /* Returns the filename prefixed by the state_dir */
 129 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 130 {
 131         static struct strbuf path = STRBUF_INIT;
 132         static size_t prefix_len;
 133
 134         if (!prefix_len) {
 135                 strbuf_addf(&path, "%s/", opts->state_dir);
 136                 prefix_len = path.len;
 137         }
 138
 139         strbuf_setlen(&path, prefix_len);
 140         strbuf_addstr(&path, filename);
 141         return path.buf;
 142 }
 143
 144 /* Read one file, then strip line endings */
 145 static int read_one(const char *path, struct strbuf *buf)
 146 {
 147         if (strbuf_read_file(buf, path, 0) < 0)
 148                 return error_errno(_("could not read '%s'"), path);
 149         strbuf_trim_trailing_newline(buf);
 150         return 0;
 151 }
 152
 153 /* Initialize the rebase options from the state directory. */
 154 static int read_basic_state(struct rebase_options *opts)
 155 {
 156         struct strbuf head_name = STRBUF_INIT;
 157         struct strbuf buf = STRBUF_INIT;
 158         struct object_id oid;
 159
 160         if (read_one(state_dir_path("head-name", opts), &head_name) ||
 161             read_one(state_dir_path("onto", opts), &buf))
 162                 return -1;
 163         opts->head_name = starts_with(head_name.buf, "refs/") ?
 164                 xstrdup(head_name.buf) : NULL;
 165         strbuf_release(&head_name);
 166         if (get_oid(buf.buf, &oid))
 167                 return error(_("could not get 'onto': '%s'"), buf.buf);
 168         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 169
 170         /*
 171          * We always write to orig-head, but interactive rebase used to write to
 172          * head. Fall back to reading from head to cover for the case that the
 173          * user upgraded git with an ongoing interactive rebase.
 174          */
 175         strbuf_reset(&buf);
 176         if (file_exists(state_dir_path("orig-head", opts))) {
 177                 if (read_one(state_dir_path("orig-head", opts), &buf))
 178                         return -1;
 179         } else if (read_one(state_dir_path("head", opts), &buf))
 180                 return -1;
 181         if (get_oid(buf.buf, &opts->orig_head))
 182                 return error(_("invalid orig-head: '%s'"), buf.buf);
 183
 184         strbuf_reset(&buf);
 185         if (read_one(state_dir_path("quiet", opts), &buf))
 186                 return -1;
 187         if (buf.len)
 188                 opts->flags &= ~REBASE_NO_QUIET;
 189         else
 190                 opts->flags |= REBASE_NO_QUIET;
 191
 192         if (file_exists(state_dir_path("verbose", opts)))
 193                 opts->flags |= REBASE_VERBOSE;
 194
 195         if (file_exists(state_dir_path("signoff", opts))) {
 196                 opts->signoff = 1;
 197                 opts->flags |= REBASE_FORCE;
 198         }
 199
 200         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 201                 strbuf_reset(&buf);
 202                 if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
 203                             &buf))
 204                         return -1;
 205                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
 206                         opts->allow_rerere_autoupdate = 1;
 207                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 208                         opts->allow_rerere_autoupdate = 0;
 209                 else
 210                         warning(_("ignoring invalid allow_rerere_autoupdate: "
 211                                   "'%s'"), buf.buf);
 212         } else
 213                 opts->allow_rerere_autoupdate = -1;
 214
 215         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 216                 strbuf_reset(&buf);
 217                 if (read_one(state_dir_path("gpg_sign_opt", opts),
 218                             &buf))
 219                         return -1;
 220                 free(opts->gpg_sign_opt);
 221                 opts->gpg_sign_opt = xstrdup(buf.buf);
 222         }
 223
 224         if (file_exists(state_dir_path("strategy", opts))) {
 225                 strbuf_reset(&buf);
 226                 if (read_one(state_dir_path("strategy", opts), &buf))
 227                         return -1;
 228                 free(opts->strategy);
 229                 opts->strategy = xstrdup(buf.buf);
 230         }
 231
 232         if (file_exists(state_dir_path("strategy_opts", opts))) {
 233                 strbuf_reset(&buf);
 234                 if (read_one(state_dir_path("strategy_opts", opts), &buf))
 235                         return -1;
 236                 free(opts->strategy_opts);
 237                 opts->strategy_opts = xstrdup(buf.buf);
 238         }
 239
 240         strbuf_release(&buf);
 241
 242         return 0;
 243 }
 244
 245 static int apply_autostash(struct rebase_options *opts)
 246 {
 247         const char *path = state_dir_path("autostash", opts);
 248         struct strbuf autostash = STRBUF_INIT;
 249         struct child_process stash_apply = CHILD_PROCESS_INIT;
 250
 251         if (!file_exists(path))
 252                 return 0;
 253
 254         if (read_one(path, &autostash))
 255                 return error(_("Could not read '%s'"), path);
 256         /* Ensure that the hash is not mistaken for a number */
 257         strbuf_addstr(&autostash, "^0");
 258         argv_array_pushl(&stash_apply.args,
 259                          "stash", "apply", autostash.buf, NULL);
 260         stash_apply.git_cmd = 1;
 261         stash_apply.no_stderr = stash_apply.no_stdout =
 262                 stash_apply.no_stdin = 1;
 263         if (!run_command(&stash_apply))
 264                 printf(_("Applied autostash.\n"));
 265         else {
 266                 struct argv_array args = ARGV_ARRAY_INIT;
 267                 int res = 0;
 268
 269                 argv_array_pushl(&args,
 270                                  "stash", "store", "-m", "autostash", "-q",
 271                                  autostash.buf, NULL);
 272                 if (run_command_v_opt(args.argv, RUN_GIT_CMD))
 273                         res = error(_("Cannot store %s"), autostash.buf);
 274                 argv_array_clear(&args);
 275                 strbuf_release(&autostash);
 276                 if (res)
 277                         return res;
 278
 279                 fprintf(stderr,
 280                         _("Applying autostash resulted in conflicts.\n"
 281                           "Your changes are safe in the stash.\n"
 282                           "You can run \"git stash pop\" or \"git stash drop\" "
 283                           "at any time.\n"));
 284         }
 285
 286         strbuf_release(&autostash);
 287         return 0;
 288 }
 289
 290 static int finish_rebase(struct rebase_options *opts)
 291 {
 292         struct strbuf dir = STRBUF_INIT;
 293         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 294
 295         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 296         apply_autostash(opts);
 297         close_all_packs(the_repository->objects);
 298         /*
 299          * We ignore errors in 'gc --auto', since the
 300          * user should see them.
 301          */
 302         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 303         strbuf_addstr(&dir, opts->state_dir);
 304         remove_dir_recursively(&dir, 0);
 305         strbuf_release(&dir);
 306
 307         return 0;
 308 }
 309
 310 static struct commit *peel_committish(const char *name)
 311 {
 312         struct object *obj;
 313         struct object_id oid;
 314
 315         if (get_oid(name, &oid))
 316                 return NULL;
 317         obj = parse_object(the_repository, &oid);
 318         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 319 }
 320
 321 static void add_var(struct strbuf *buf, const char *name, const char *value)
 322 {
 323         if (!value)
 324                 strbuf_addf(buf, "unset %s; ", name);
 325         else {
 326                 strbuf_addf(buf, "%s=", name);
 327                 sq_quote_buf(buf, value);
 328                 strbuf_addstr(buf, "; ");
 329         }
 330 }
 331
 332 static const char *resolvemsg =
 333 N_("Resolve all conflicts manually, mark them as resolved with\n"
 334 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 335 "You can instead skip this commit: run \"git rebase --skip\".\n"
 336 "To abort and get back to the state before \"git rebase\", run "
 337 "\"git rebase --abort\".");
 338
 339 static int run_specific_rebase(struct rebase_options *opts)
 340 {
 341         const char *argv[] = { NULL, NULL };
 342         struct strbuf script_snippet = STRBUF_INIT;
 343         int status;
 344         const char *backend, *backend_func;
 345
 346         if (opts->type == REBASE_INTERACTIVE) {
 347                 /* Run builtin interactive rebase */
 348                 struct child_process child = CHILD_PROCESS_INIT;
 349
 350                 argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
 351                                  resolvemsg);
 352                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 353                         argv_array_push(&child.env_array, "GIT_EDITOR=:");
 354                         opts->autosquash = 0;
 355                 }
 356
 357                 child.git_cmd = 1;
 358                 argv_array_push(&child.args, "rebase--interactive");
 359
 360                 if (opts->action)
 361                         argv_array_pushf(&child.args, "--%s", opts->action);
 362                 if (opts->keep_empty)
 363                         argv_array_push(&child.args, "--keep-empty");
 364                 if (opts->rebase_merges)
 365                         argv_array_push(&child.args, "--rebase-merges");
 366                 if (opts->rebase_cousins)
 367                         argv_array_push(&child.args, "--rebase-cousins");
 368                 if (opts->autosquash)
 369                         argv_array_push(&child.args, "--autosquash");
 370                 if (opts->flags & REBASE_VERBOSE)
 371                         argv_array_push(&child.args, "--verbose");
 372                 if (opts->flags & REBASE_FORCE)
 373                         argv_array_push(&child.args, "--no-ff");
 374                 if (opts->restrict_revision)
 375                         argv_array_pushf(&child.args,
 376                                          "--restrict-revision=^%s",
 377                                          oid_to_hex(&opts->restrict_revision->object.oid));
 378                 if (opts->upstream)
 379                         argv_array_pushf(&child.args, "--upstream=%s",
 380                                          oid_to_hex(&opts->upstream->object.oid));
 381                 if (opts->onto)
 382                         argv_array_pushf(&child.args, "--onto=%s",
 383                                          oid_to_hex(&opts->onto->object.oid));
 384                 if (opts->squash_onto)
 385                         argv_array_pushf(&child.args, "--squash-onto=%s",
 386                                          oid_to_hex(opts->squash_onto));
 387                 if (opts->onto_name)
 388                         argv_array_pushf(&child.args, "--onto-name=%s",
 389                                          opts->onto_name);
 390                 argv_array_pushf(&child.args, "--head-name=%s",
 391                                  opts->head_name ?
 392                                  opts->head_name : "detached HEAD");
 393                 if (opts->strategy)
 394                         argv_array_pushf(&child.args, "--strategy=%s",
 395                                          opts->strategy);
 396                 if (opts->strategy_opts)
 397                         argv_array_pushf(&child.args, "--strategy-opts=%s",
 398                                          opts->strategy_opts);
 399                 if (opts->switch_to)
 400                         argv_array_pushf(&child.args, "--switch-to=%s",
 401                                          opts->switch_to);
 402                 if (opts->cmd)
 403                         argv_array_pushf(&child.args, "--cmd=%s", opts->cmd);
 404                 if (opts->allow_empty_message)
 405                         argv_array_push(&child.args, "--allow-empty-message");
 406                 if (opts->allow_rerere_autoupdate > 0)
 407                         argv_array_push(&child.args, "--rerere-autoupdate");
 408                 else if (opts->allow_rerere_autoupdate == 0)
 409                         argv_array_push(&child.args, "--no-rerere-autoupdate");
 410                 if (opts->gpg_sign_opt)
 411                         argv_array_push(&child.args, opts->gpg_sign_opt);
 412                 if (opts->signoff)
 413                         argv_array_push(&child.args, "--signoff");
 414
 415                 status = run_command(&child);
 416                 goto finished_rebase;
 417         }
 418
 419         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 420         add_var(&script_snippet, "state_dir", opts->state_dir);
 421
 422         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 423         add_var(&script_snippet, "upstream", opts->upstream ?
 424                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 425         add_var(&script_snippet, "head_name",
 426                 opts->head_name ? opts->head_name : "detached HEAD");
 427         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 428         add_var(&script_snippet, "onto", opts->onto ?
 429                 oid_to_hex(&opts->onto->object.oid) : NULL);
 430         add_var(&script_snippet, "onto_name", opts->onto_name);
 431         add_var(&script_snippet, "revisions", opts->revisions);
 432         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 433                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 434         add_var(&script_snippet, "GIT_QUIET",
 435                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 436         add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 437         add_var(&script_snippet, "verbose",
 438                 opts->flags & REBASE_VERBOSE ? "t" : "");
 439         add_var(&script_snippet, "diffstat",
 440                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 441         add_var(&script_snippet, "force_rebase",
 442                 opts->flags & REBASE_FORCE ? "t" : "");
 443         if (opts->switch_to)
 444                 add_var(&script_snippet, "switch_to", opts->switch_to);
 445         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 446         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 447         add_var(&script_snippet, "allow_rerere_autoupdate",
 448                 opts->allow_rerere_autoupdate < 0 ? "" :
 449                 opts->allow_rerere_autoupdate ?
 450                 "--rerere-autoupdate" : "--no-rerere-autoupdate");
 451         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 452         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 453         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 454         add_var(&script_snippet, "cmd", opts->cmd);
 455         add_var(&script_snippet, "allow_empty_message",
 456                 opts->allow_empty_message ?  "--allow-empty-message" : "");
 457         add_var(&script_snippet, "rebase_merges",
 458                 opts->rebase_merges ? "t" : "");
 459         add_var(&script_snippet, "rebase_cousins",
 460                 opts->rebase_cousins ? "t" : "");
 461         add_var(&script_snippet, "strategy", opts->strategy);
 462         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
 463         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
 464         add_var(&script_snippet, "squash_onto",
 465                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
 466         add_var(&script_snippet, "git_format_patch_opt",
 467                 opts->git_format_patch_opt.buf);
 468
 469         if (is_interactive(opts) &&
 470             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 471                 strbuf_addstr(&script_snippet,
 472                               "GIT_EDITOR=:; export GIT_EDITOR; ");
 473                 opts->autosquash = 0;
 474         }
 475
 476         switch (opts->type) {
 477         case REBASE_AM:
 478                 backend = "git-rebase--am";
 479                 backend_func = "git_rebase__am";
 480                 break;
 481         case REBASE_MERGE:
 482                 backend = "git-rebase--merge";
 483                 backend_func = "git_rebase__merge";
 484                 break;
 485         case REBASE_PRESERVE_MERGES:
 486                 backend = "git-rebase--preserve-merges";
 487                 backend_func = "git_rebase__preserve_merges";
 488                 break;
 489         default:
 490                 BUG("Unhandled rebase type %d", opts->type);
 491                 break;
 492         }
 493
 494         strbuf_addf(&script_snippet,
 495                     ". git-sh-setup && . git-rebase--common &&"
 496                     " . %s && %s", backend, backend_func);
 497         argv[0] = script_snippet.buf;
 498
 499         status = run_command_v_opt(argv, RUN_USING_SHELL);
 500 finished_rebase:
 501         if (opts->dont_finish_rebase)
 502                 ; /* do nothing */
 503         else if (opts->type == REBASE_INTERACTIVE)
 504                 ; /* interactive rebase cleans up after itself */
 505         else if (status == 0) {
 506                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 507                         finish_rebase(opts);
 508         } else if (status == 2) {
 509                 struct strbuf dir = STRBUF_INIT;
 510
 511                 apply_autostash(opts);
 512                 strbuf_addstr(&dir, opts->state_dir);
 513                 remove_dir_recursively(&dir, 0);
 514                 strbuf_release(&dir);
 515                 die("Nothing to do");
 516         }
 517
 518         strbuf_release(&script_snippet);
 519
 520         return status ? -1 : 0;
 521 }
 522
 523 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 524
 525 static int reset_head(struct object_id *oid, const char *action,
 526                       const char *switch_to_branch, int detach_head,
 527                       const char *reflog_orig_head, const char *reflog_head)
 528 {
 529         struct object_id head_oid;
 530         struct tree_desc desc;
 531         struct lock_file lock = LOCK_INIT;
 532         struct unpack_trees_options unpack_tree_opts;
 533         struct tree *tree;
 534         const char *reflog_action;
 535         struct strbuf msg = STRBUF_INIT;
 536         size_t prefix_len;
 537         struct object_id *orig = NULL, oid_orig,
 538                 *old_orig = NULL, oid_old_orig;
 539         int ret = 0;
 540
 541         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 542                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 543
 544         if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 545                 return -1;
 546
 547         if (!oid) {
 548                 if (get_oid("HEAD", &head_oid)) {
 549                         rollback_lock_file(&lock);
 550                         return error(_("could not determine HEAD revision"));
 551                 }
 552                 oid = &head_oid;
 553         }
 554
 555         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 556         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 557         unpack_tree_opts.head_idx = 1;
 558         unpack_tree_opts.src_index = the_repository->index;
 559         unpack_tree_opts.dst_index = the_repository->index;
 560         unpack_tree_opts.fn = oneway_merge;
 561         unpack_tree_opts.update = 1;
 562         unpack_tree_opts.merge = 1;
 563         if (!detach_head)
 564                 unpack_tree_opts.reset = 1;
 565
 566         if (read_index_unmerged(the_repository->index) < 0) {
 567                 rollback_lock_file(&lock);
 568                 return error(_("could not read index"));
 569         }
 570
 571         if (!fill_tree_descriptor(&desc, oid)) {
 572                 error(_("failed to find tree of %s"), oid_to_hex(oid));
 573                 rollback_lock_file(&lock);
 574                 free((void *)desc.buffer);
 575                 return -1;
 576         }
 577
 578         if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 579                 rollback_lock_file(&lock);
 580                 free((void *)desc.buffer);
 581                 return -1;
 582         }
 583
 584         tree = parse_tree_indirect(oid);
 585         prime_cache_tree(the_repository, the_repository->index, tree);
 586
 587         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 588                 ret = error(_("could not write index"));
 589         free((void *)desc.buffer);
 590
 591         if (ret)
 592                 return ret;
 593
 594         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 595         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 596         prefix_len = msg.len;
 597
 598         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 599                 old_orig = &oid_old_orig;
 600         if (!get_oid("HEAD", &oid_orig)) {
 601                 orig = &oid_orig;
 602                 if (!reflog_orig_head) {
 603                         strbuf_addstr(&msg, "updating ORIG_HEAD");
 604                         reflog_orig_head = msg.buf;
 605                 }
 606                 update_ref(reflog_orig_head, "ORIG_HEAD", orig, old_orig, 0,
 607                            UPDATE_REFS_MSG_ON_ERR);
 608         } else if (old_orig)
 609                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 610         if (!reflog_head) {
 611                 strbuf_setlen(&msg, prefix_len);
 612                 strbuf_addstr(&msg, "updating HEAD");
 613                 reflog_head = msg.buf;
 614         }
 615         if (!switch_to_branch)
 616                 ret = update_ref(reflog_head, "HEAD", oid, orig, REF_NO_DEREF,
 617                                  UPDATE_REFS_MSG_ON_ERR);
 618         else {
 619                 ret = create_symref("HEAD", switch_to_branch, msg.buf);
 620                 if (!ret)
 621                         ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
 622                                          UPDATE_REFS_MSG_ON_ERR);
 623         }
 624
 625         strbuf_release(&msg);
 626         return ret;
 627 }
 628
 629 static int rebase_config(const char *var, const char *value, void *data)
 630 {
 631         struct rebase_options *opts = data;
 632
 633         if (!strcmp(var, "rebase.stat")) {
 634                 if (git_config_bool(var, value))
 635                         opts->flags |= REBASE_DIFFSTAT;
 636                 else
 637                         opts->flags &= !REBASE_DIFFSTAT;
 638                 return 0;
 639         }
 640
 641         if (!strcmp(var, "rebase.autosquash")) {
 642                 opts->autosquash = git_config_bool(var, value);
 643                 return 0;
 644         }
 645
 646         if (!strcmp(var, "commit.gpgsign")) {
 647                 free(opts->gpg_sign_opt);
 648                 opts->gpg_sign_opt = git_config_bool(var, value) ?
 649                         xstrdup("-S") : NULL;
 650                 return 0;
 651         }
 652
 653         if (!strcmp(var, "rebase.autostash")) {
 654                 opts->autostash = git_config_bool(var, value);
 655                 return 0;
 656         }
 657
 658         return git_default_config(var, value, data);
 659 }
 660
 661 /*
 662  * Determines whether the commits in from..to are linear, i.e. contain
 663  * no merge commits. This function *expects* `from` to be an ancestor of
 664  * `to`.
 665  */
 666 static int is_linear_history(struct commit *from, struct commit *to)
 667 {
 668         while (to && to != from) {
 669                 parse_commit(to);
 670                 if (!to->parents)
 671                         return 1;
 672                 if (to->parents->next)
 673                         return 0;
 674                 to = to->parents->item;
 675         }
 676         return 1;
 677 }
 678
 679 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 680                             struct object_id *merge_base)
 681 {
 682         struct commit *head = lookup_commit(the_repository, head_oid);
 683         struct commit_list *merge_bases;
 684         int res;
 685
 686         if (!head)
 687                 return 0;
 688
 689         merge_bases = get_merge_bases(onto, head);
 690         if (merge_bases && !merge_bases->next) {
 691                 oidcpy(merge_base, &merge_bases->item->object.oid);
 692                 res = oideq(merge_base, &onto->object.oid);
 693         } else {
 694                 oidcpy(merge_base, &null_oid);
 695                 res = 0;
 696         }
 697         free_commit_list(merge_bases);
 698         return res && is_linear_history(onto, head);
 699 }
 700
 701 /* -i followed by -m is still -i */
 702 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 703 {
 704         struct rebase_options *opts = opt->value;
 705
 706         if (!is_interactive(opts))
 707                 opts->type = REBASE_MERGE;
 708
 709         return 0;
 710 }
 711
 712 /* -i followed by -p is still explicitly interactive, but -p alone is not */
 713 static int parse_opt_interactive(const struct option *opt, const char *arg,
 714                                  int unset)
 715 {
 716         struct rebase_options *opts = opt->value;
 717
 718         opts->type = REBASE_INTERACTIVE;
 719         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 720
 721         return 0;
 722 }
 723
 724 static void NORETURN error_on_missing_default_upstream(void)
 725 {
 726         struct branch *current_branch = branch_get(NULL);
 727
 728         printf(_("%s\n"
 729                  "Please specify which branch you want to rebase against.\n"
 730                  "See git-rebase(1) for details.\n"
 731                  "\n"
 732                  "    git rebase '<branch>'\n"
 733                  "\n"),
 734                 current_branch ? _("There is no tracking information for "
 735                         "the current branch.") :
 736                         _("You are not currently on a branch."));
 737
 738         if (current_branch) {
 739                 const char *remote = current_branch->remote_name;
 740
 741                 if (!remote)
 742                         remote = _("<remote>");
 743
 744                 printf(_("If you wish to set tracking information for this "
 745                          "branch you can do so with:\n"
 746                          "\n"
 747                          "    git branch --set-upstream-to=%s/<branch> %s\n"
 748                          "\n"),
 749                        remote, current_branch->name);
 750         }
 751         exit(1);
 752 }
 753
 754 int cmd_rebase(int argc, const char **argv, const char *prefix)
 755 {
 756         struct rebase_options options = {
 757                 .type = REBASE_UNSPECIFIED,
 758                 .flags = REBASE_NO_QUIET,
 759                 .git_am_opt = STRBUF_INIT,
 760                 .allow_rerere_autoupdate  = -1,
 761                 .allow_empty_message = 1,
 762                 .git_format_patch_opt = STRBUF_INIT,
 763         };
 764         const char *branch_name;
 765         int ret, flags, total_argc, in_progress = 0;
 766         int ok_to_skip_pre_rebase = 0;
 767         struct strbuf msg = STRBUF_INIT;
 768         struct strbuf revisions = STRBUF_INIT;
 769         struct strbuf buf = STRBUF_INIT;
 770         struct object_id merge_base;
 771         enum {
 772                 NO_ACTION,
 773                 ACTION_CONTINUE,
 774                 ACTION_SKIP,
 775                 ACTION_ABORT,
 776                 ACTION_QUIT,
 777                 ACTION_EDIT_TODO,
 778                 ACTION_SHOW_CURRENT_PATCH,
 779         } action = NO_ACTION;
 780         int committer_date_is_author_date = 0;
 781         int ignore_date = 0;
 782         int ignore_whitespace = 0;
 783         const char *gpg_sign = NULL;
 784         int opt_c = -1;
 785         struct string_list whitespace = STRING_LIST_INIT_NODUP;
 786         struct string_list exec = STRING_LIST_INIT_NODUP;
 787         const char *rebase_merges = NULL;
 788         int fork_point = -1;
 789         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
 790         struct object_id squash_onto;
 791         char *squash_onto_name = NULL;
 792         struct option builtin_rebase_options[] = {
 793                 OPT_STRING(0, "onto", &options.onto_name,
 794                            N_("revision"),
 795                            N_("rebase onto given branch instead of upstream")),
 796                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 797                          N_("allow pre-rebase hook to run")),
 798                 OPT_NEGBIT('q', "quiet", &options.flags,
 799                            N_("be quiet. implies --no-stat"),
 800                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 801                 OPT_BIT('v', "verbose", &options.flags,
 802                         N_("display a diffstat of what changed upstream"),
 803                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 804                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 805                         N_("do not show diffstat of what changed upstream"),
 806                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 807                 OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
 808                          N_("passed to 'git apply'")),
 809                 OPT_BOOL(0, "signoff", &options.signoff,
 810                          N_("add a Signed-off-by: line to each commit")),
 811                 OPT_BOOL(0, "committer-date-is-author-date",
 812                          &committer_date_is_author_date,
 813                          N_("passed to 'git am'")),
 814                 OPT_BOOL(0, "ignore-date", &ignore_date,
 815                          N_("passed to 'git am'")),
 816                 OPT_BIT('f', "force-rebase", &options.flags,
 817                         N_("cherry-pick all commits, even if unchanged"),
 818                         REBASE_FORCE),
 819                 OPT_BIT(0, "no-ff", &options.flags,
 820                         N_("cherry-pick all commits, even if unchanged"),
 821                         REBASE_FORCE),
 822                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
 823                             ACTION_CONTINUE),
 824                 OPT_CMDMODE(0, "skip", &action,
 825                             N_("skip current patch and continue"), ACTION_SKIP),
 826                 OPT_CMDMODE(0, "abort", &action,
 827                             N_("abort and check out the original branch"),
 828                             ACTION_ABORT),
 829                 OPT_CMDMODE(0, "quit", &action,
 830                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
 831                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
 832                             "during an interactive rebase"), ACTION_EDIT_TODO),
 833                 OPT_CMDMODE(0, "show-current-patch", &action,
 834                             N_("show the patch file being applied or merged"),
 835                             ACTION_SHOW_CURRENT_PATCH),
 836                 { OPTION_CALLBACK, 'm', "merge", &options, NULL,
 837                         N_("use merging strategies to rebase"),
 838                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 839                         parse_opt_merge },
 840                 { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
 841                         N_("let the user edit the list of commits to rebase"),
 842                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 843                         parse_opt_interactive },
 844                 OPT_SET_INT('p', "preserve-merges", &options.type,
 845                             N_("try to recreate merges instead of ignoring "
 846                                "them"), REBASE_PRESERVE_MERGES),
 847                 OPT_BOOL(0, "rerere-autoupdate",
 848                          &options.allow_rerere_autoupdate,
 849                          N_("allow rerere to update index  with resolved "
 850                             "conflict")),
 851                 OPT_BOOL('k', "keep-empty", &options.keep_empty,
 852                          N_("preserve empty commits during rebase")),
 853                 OPT_BOOL(0, "autosquash", &options.autosquash,
 854                          N_("move commits that begin with "
 855                             "squash!/fixup! under -i")),
 856                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 857                         N_("GPG-sign commits"),
 858                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 859                 OPT_STRING_LIST(0, "whitespace", &whitespace,
 860                                 N_("whitespace"), N_("passed to 'git apply'")),
 861                 OPT_SET_INT('C', NULL, &opt_c, N_("passed to 'git apply'"),
 862                             REBASE_AM),
 863                 OPT_BOOL(0, "autostash", &options.autostash,
 864                          N_("automatically stash/stash pop before and after")),
 865                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
 866                                 N_("add exec lines after each commit of the "
 867                                    "editable list")),
 868                 OPT_BOOL(0, "allow-empty-message",
 869                          &options.allow_empty_message,
 870                          N_("allow rebasing commits with empty messages")),
 871                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
 872                         N_("mode"),
 873                         N_("try to rebase merges instead of skipping them"),
 874                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
 875                 OPT_BOOL(0, "fork-point", &fork_point,
 876                          N_("use 'merge-base --fork-point' to refine upstream")),
 877                 OPT_STRING('s', "strategy", &options.strategy,
 878                            N_("strategy"), N_("use the given merge strategy")),
 879                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
 880                                 N_("option"),
 881                                 N_("pass the argument through to the merge "
 882                                    "strategy")),
 883                 OPT_BOOL(0, "root", &options.root,
 884                          N_("rebase all reachable commits up to the root(s)")),
 885                 OPT_END(),
 886         };
 887
 888         /*
 889          * NEEDSWORK: Once the builtin rebase has been tested enough
 890          * and git-legacy-rebase.sh is retired to contrib/, this preamble
 891          * can be removed.
 892          */
 893
 894         if (!use_builtin_rebase()) {
 895                 const char *path = mkpath("%s/git-legacy-rebase",
 896                                           git_exec_path());
 897
 898                 if (sane_execvp(path, (char **)argv) < 0)
 899                         die_errno(_("could not exec %s"), path);
 900                 else
 901                         BUG("sane_execvp() returned???");
 902         }
 903
 904         if (argc == 2 && !strcmp(argv[1], "-h"))
 905                 usage_with_options(builtin_rebase_usage,
 906                                    builtin_rebase_options);
 907
 908         prefix = setup_git_directory();
 909         trace_repo_setup(prefix);
 910         setup_work_tree();
 911
 912         git_config(rebase_config, &options);
 913
 914         strbuf_reset(&buf);
 915         strbuf_addf(&buf, "%s/applying", apply_dir());
 916         if(file_exists(buf.buf))
 917                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
 918
 919         if (is_directory(apply_dir())) {
 920                 options.type = REBASE_AM;
 921                 options.state_dir = apply_dir();
 922         } else if (is_directory(merge_dir())) {
 923                 strbuf_reset(&buf);
 924                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
 925                 if (is_directory(buf.buf)) {
 926                         options.type = REBASE_PRESERVE_MERGES;
 927                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 928                 } else {
 929                         strbuf_reset(&buf);
 930                         strbuf_addf(&buf, "%s/interactive", merge_dir());
 931                         if(file_exists(buf.buf)) {
 932                                 options.type = REBASE_INTERACTIVE;
 933                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 934                         } else
 935                                 options.type = REBASE_MERGE;
 936                 }
 937                 options.state_dir = merge_dir();
 938         }
 939
 940         if (options.type != REBASE_UNSPECIFIED)
 941                 in_progress = 1;
 942
 943         total_argc = argc;
 944         argc = parse_options(argc, argv, prefix,
 945                              builtin_rebase_options,
 946                              builtin_rebase_usage, 0);
 947
 948         if (action != NO_ACTION && total_argc != 2) {
 949                 usage_with_options(builtin_rebase_usage,
 950                                    builtin_rebase_options);
 951         }
 952
 953         if (argc > 2)
 954                 usage_with_options(builtin_rebase_usage,
 955                                    builtin_rebase_options);
 956
 957         if (action != NO_ACTION && !in_progress)
 958                 die(_("No rebase in progress?"));
 959
 960         if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 961                 die(_("The --edit-todo action can only be used during "
 962                       "interactive rebase."));
 963
 964         switch (action) {
 965         case ACTION_CONTINUE: {
 966                 struct object_id head;
 967                 struct lock_file lock_file = LOCK_INIT;
 968                 int fd;
 969
 970                 options.action = "continue";
 971
 972                 /* Sanity check */
 973                 if (get_oid("HEAD", &head))
 974                         die(_("Cannot read HEAD"));
 975
 976                 fd = hold_locked_index(&lock_file, 0);
 977                 if (read_index(the_repository->index) < 0)
 978                         die(_("could not read index"));
 979                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 980                               NULL);
 981                 if (0 <= fd)
 982                         update_index_if_able(the_repository->index,
 983                                              &lock_file);
 984                 rollback_lock_file(&lock_file);
 985
 986                 if (has_unstaged_changes(the_repository, 1)) {
 987                         puts(_("You must edit all merge conflicts and then\n"
 988                                "mark them as resolved using git add"));
 989                         exit(1);
 990                 }
 991                 if (read_basic_state(&options))
 992                         exit(1);
 993                 goto run_rebase;
 994         }
 995         case ACTION_SKIP: {
 996                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
 997
 998                 options.action = "skip";
 999
1000                 rerere_clear(&merge_rr);
1001                 string_list_clear(&merge_rr, 1);
1002
1003                 if (reset_head(NULL, "reset", NULL, 0, NULL, NULL) < 0)
1004                         die(_("could not discard worktree changes"));
1005                 if (read_basic_state(&options))
1006                         exit(1);
1007                 goto run_rebase;
1008         }
1009         case ACTION_ABORT: {
1010                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1011                 options.action = "abort";
1012
1013                 rerere_clear(&merge_rr);
1014                 string_list_clear(&merge_rr, 1);
1015
1016                 if (read_basic_state(&options))
1017                         exit(1);
1018                 if (reset_head(&options.orig_head, "reset",
1019                                options.head_name, 0, NULL, NULL) < 0)
1020                         die(_("could not move back to %s"),
1021                             oid_to_hex(&options.orig_head));
1022                 ret = finish_rebase(&options);
1023                 goto cleanup;
1024         }
1025         case ACTION_QUIT: {
1026                 strbuf_reset(&buf);
1027                 strbuf_addstr(&buf, options.state_dir);
1028                 ret = !!remove_dir_recursively(&buf, 0);
1029                 if (ret)
1030                         die(_("could not remove '%s'"), options.state_dir);
1031                 goto cleanup;
1032         }
1033         case ACTION_EDIT_TODO:
1034                 options.action = "edit-todo";
1035                 options.dont_finish_rebase = 1;
1036                 goto run_rebase;
1037         case ACTION_SHOW_CURRENT_PATCH:
1038                 options.action = "show-current-patch";
1039                 options.dont_finish_rebase = 1;
1040                 goto run_rebase;
1041         case NO_ACTION:
1042                 break;
1043         default:
1044                 BUG("action: %d", action);
1045         }
1046
1047         /* Make sure no rebase is in progress */
1048         if (in_progress) {
1049                 const char *last_slash = strrchr(options.state_dir, '/');
1050                 const char *state_dir_base =
1051                         last_slash ? last_slash + 1 : options.state_dir;
1052                 const char *cmd_live_rebase =
1053                         "git rebase (--continue | --abort | --skip)";
1054                 strbuf_reset(&buf);
1055                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1056                 die(_("It seems that there is already a %s directory, and\n"
1057                       "I wonder if you are in the middle of another rebase.  "
1058                       "If that is the\n"
1059                       "case, please try\n\t%s\n"
1060                       "If that is not the case, please\n\t%s\n"
1061                       "and run me again.  I am stopping in case you still "
1062                       "have something\n"
1063                       "valuable there.\n"),
1064                     state_dir_base, cmd_live_rebase, buf.buf);
1065         }
1066
1067         if (!(options.flags & REBASE_NO_QUIET))
1068                 strbuf_addstr(&options.git_am_opt, " -q");
1069
1070         if (committer_date_is_author_date) {
1071                 strbuf_addstr(&options.git_am_opt,
1072                               " --committer-date-is-author-date");
1073                 options.flags |= REBASE_FORCE;
1074         }
1075
1076         if (ignore_whitespace)
1077                 strbuf_addstr(&options.git_am_opt, " --ignore-whitespace");
1078
1079         if (ignore_date) {
1080                 strbuf_addstr(&options.git_am_opt, " --ignore-date");
1081                 options.flags |= REBASE_FORCE;
1082         }
1083
1084         if (options.keep_empty)
1085                 imply_interactive(&options, "--keep-empty");
1086
1087         if (gpg_sign) {
1088                 free(options.gpg_sign_opt);
1089                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1090         }
1091
1092         if (opt_c >= 0)
1093                 strbuf_addf(&options.git_am_opt, " -C%d", opt_c);
1094
1095         if (whitespace.nr) {
1096                 int i;
1097
1098                 for (i = 0; i < whitespace.nr; i++) {
1099                         const char *item = whitespace.items[i].string;
1100
1101                         strbuf_addf(&options.git_am_opt, " --whitespace=%s",
1102                                     item);
1103
1104                         if ((!strcmp(item, "fix")) || (!strcmp(item, "strip")))
1105                                 options.flags |= REBASE_FORCE;
1106                 }
1107         }
1108
1109         if (exec.nr) {
1110                 int i;
1111
1112                 imply_interactive(&options, "--exec");
1113
1114                 strbuf_reset(&buf);
1115                 for (i = 0; i < exec.nr; i++)
1116                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1117                 options.cmd = xstrdup(buf.buf);
1118         }
1119
1120         if (rebase_merges) {
1121                 if (!*rebase_merges)
1122                         ; /* default mode; do nothing */
1123                 else if (!strcmp("rebase-cousins", rebase_merges))
1124                         options.rebase_cousins = 1;
1125                 else if (strcmp("no-rebase-cousins", rebase_merges))
1126                         die(_("Unknown mode: %s"), rebase_merges);
1127                 options.rebase_merges = 1;
1128                 imply_interactive(&options, "--rebase-merges");
1129         }
1130
1131         if (strategy_options.nr) {
1132                 int i;
1133
1134                 if (!options.strategy)
1135                         options.strategy = "recursive";
1136
1137                 strbuf_reset(&buf);
1138                 for (i = 0; i < strategy_options.nr; i++)
1139                         strbuf_addf(&buf, " --%s",
1140                                     strategy_options.items[i].string);
1141                 options.strategy_opts = xstrdup(buf.buf);
1142         }
1143
1144         if (options.strategy) {
1145                 options.strategy = xstrdup(options.strategy);
1146                 switch (options.type) {
1147                 case REBASE_AM:
1148                         die(_("--strategy requires --merge or --interactive"));
1149                 case REBASE_MERGE:
1150                 case REBASE_INTERACTIVE:
1151                 case REBASE_PRESERVE_MERGES:
1152                         /* compatible */
1153                         break;
1154                 case REBASE_UNSPECIFIED:
1155                         options.type = REBASE_MERGE;
1156                         break;
1157                 default:
1158                         BUG("unhandled rebase type (%d)", options.type);
1159                 }
1160         }
1161
1162         if (options.root && !options.onto_name)
1163                 imply_interactive(&options, "--root without --onto");
1164
1165         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1166                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1167
1168         switch (options.type) {
1169         case REBASE_MERGE:
1170         case REBASE_INTERACTIVE:
1171         case REBASE_PRESERVE_MERGES:
1172                 options.state_dir = merge_dir();
1173                 break;
1174         case REBASE_AM:
1175                 options.state_dir = apply_dir();
1176                 break;
1177         default:
1178                 /* the default rebase backend is `--am` */
1179                 options.type = REBASE_AM;
1180                 options.state_dir = apply_dir();
1181                 break;
1182         }
1183
1184         if (options.git_am_opt.len) {
1185                 const char *p;
1186
1187                 /* all am options except -q are compatible only with --am */
1188                 strbuf_reset(&buf);
1189                 strbuf_addbuf(&buf, &options.git_am_opt);
1190                 strbuf_addch(&buf, ' ');
1191                 while ((p = strstr(buf.buf, " -q ")))
1192                         strbuf_splice(&buf, p - buf.buf, 4, " ", 1);
1193                 strbuf_trim(&buf);
1194
1195                 if (is_interactive(&options) && buf.len)
1196                         die(_("error: cannot combine interactive options "
1197                               "(--interactive, --exec, --rebase-merges, "
1198                               "--preserve-merges, --keep-empty, --root + "
1199                               "--onto) with am options (%s)"), buf.buf);
1200                 if (options.type == REBASE_MERGE && buf.len)
1201                         die(_("error: cannot combine merge options (--merge, "
1202                               "--strategy, --strategy-option) with am options "
1203                               "(%s)"), buf.buf);
1204         }
1205
1206         if (options.signoff) {
1207                 if (options.type == REBASE_PRESERVE_MERGES)
1208                         die("cannot combine '--signoff' with "
1209                             "'--preserve-merges'");
1210                 strbuf_addstr(&options.git_am_opt, " --signoff");
1211                 options.flags |= REBASE_FORCE;
1212         }
1213
1214         if (options.type == REBASE_PRESERVE_MERGES)
1215                 /*
1216                  * Note: incompatibility with --signoff handled in signoff block above
1217                  * Note: incompatibility with --interactive is just a strong warning;
1218                  *       git-rebase.txt caveats with "unless you know what you are doing"
1219                  */
1220                 if (options.rebase_merges)
1221                         die(_("error: cannot combine '--preserve-merges' with "
1222                               "'--rebase-merges'"));
1223
1224         if (options.rebase_merges) {
1225                 if (strategy_options.nr)
1226                         die(_("error: cannot combine '--rebase-merges' with "
1227                               "'--strategy-option'"));
1228                 if (options.strategy)
1229                         die(_("error: cannot combine '--rebase-merges' with "
1230                               "'--strategy'"));
1231         }
1232
1233         if (!options.root) {
1234                 if (argc < 1) {
1235                         struct branch *branch;
1236
1237                         branch = branch_get(NULL);
1238                         options.upstream_name = branch_get_upstream(branch,
1239                                                                     NULL);
1240                         if (!options.upstream_name)
1241                                 error_on_missing_default_upstream();
1242                         if (fork_point < 0)
1243                                 fork_point = 1;
1244                 } else {
1245                         options.upstream_name = argv[0];
1246                         argc--;
1247                         argv++;
1248                         if (!strcmp(options.upstream_name, "-"))
1249                                 options.upstream_name = "@{-1}";
1250                 }
1251                 options.upstream = peel_committish(options.upstream_name);
1252                 if (!options.upstream)
1253                         die(_("invalid upstream '%s'"), options.upstream_name);
1254                 options.upstream_arg = options.upstream_name;
1255         } else {
1256                 if (!options.onto_name) {
1257                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1258                                         &squash_onto, NULL, NULL) < 0)
1259                                 die(_("Could not create new root commit"));
1260                         options.squash_onto = &squash_onto;
1261                         options.onto_name = squash_onto_name =
1262                                 xstrdup(oid_to_hex(&squash_onto));
1263                 }
1264                 options.upstream_name = NULL;
1265                 options.upstream = NULL;
1266                 if (argc > 1)
1267                         usage_with_options(builtin_rebase_usage,
1268                                            builtin_rebase_options);
1269                 options.upstream_arg = "--root";
1270         }
1271
1272         /* Make sure the branch to rebase onto is valid. */
1273         if (!options.onto_name)
1274                 options.onto_name = options.upstream_name;
1275         if (strstr(options.onto_name, "...")) {
1276                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
1277                         die(_("'%s': need exactly one merge base"),
1278                             options.onto_name);
1279                 options.onto = lookup_commit_or_die(&merge_base,
1280                                                     options.onto_name);
1281         } else {
1282                 options.onto = peel_committish(options.onto_name);
1283                 if (!options.onto)
1284                         die(_("Does not point to a valid commit '%s'"),
1285                                 options.onto_name);
1286         }
1287
1288         /*
1289          * If the branch to rebase is given, that is the branch we will rebase
1290          * branch_name -- branch/commit being rebased, or
1291          *                HEAD (already detached)
1292          * orig_head -- commit object name of tip of the branch before rebasing
1293          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1294          */
1295         if (argc == 1) {
1296                 /* Is it "rebase other branchname" or "rebase other commit"? */
1297                 branch_name = argv[0];
1298                 options.switch_to = argv[0];
1299
1300                 /* Is it a local branch? */
1301                 strbuf_reset(&buf);
1302                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1303                 if (!read_ref(buf.buf, &options.orig_head))
1304                         options.head_name = xstrdup(buf.buf);
1305                 /* If not is it a valid ref (branch or commit)? */
1306                 else if (!get_oid(branch_name, &options.orig_head))
1307                         options.head_name = NULL;
1308                 else
1309                         die(_("fatal: no such branch/commit '%s'"),
1310                             branch_name);
1311         } else if (argc == 0) {
1312                 /* Do not need to switch branches, we are already on it. */
1313                 options.head_name =
1314                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1315                                          &flags));
1316                 if (!options.head_name)
1317                         die(_("No such ref: %s"), "HEAD");
1318                 if (flags & REF_ISSYMREF) {
1319                         if (!skip_prefix(options.head_name,
1320                                          "refs/heads/", &branch_name))
1321                                 branch_name = options.head_name;
1322
1323                 } else {
1324                         free(options.head_name);
1325                         options.head_name = NULL;
1326                         branch_name = "HEAD";
1327                 }
1328                 if (get_oid("HEAD", &options.orig_head))
1329                         die(_("Could not resolve HEAD to a revision"));
1330         } else
1331                 BUG("unexpected number of arguments left to parse");
1332
1333         if (fork_point > 0) {
1334                 struct commit *head =
1335                         lookup_commit_reference(the_repository,
1336                                                 &options.orig_head);
1337                 options.restrict_revision =
1338                         get_fork_point(options.upstream_name, head);
1339         }
1340
1341         if (read_index(the_repository->index) < 0)
1342                 die(_("could not read index"));
1343
1344         if (options.autostash) {
1345                 struct lock_file lock_file = LOCK_INIT;
1346                 int fd;
1347
1348                 fd = hold_locked_index(&lock_file, 0);
1349                 refresh_cache(REFRESH_QUIET);
1350                 if (0 <= fd)
1351                         update_index_if_able(&the_index, &lock_file);
1352                 rollback_lock_file(&lock_file);
1353
1354                 if (has_unstaged_changes(the_repository, 1) ||
1355                     has_uncommitted_changes(the_repository, 1)) {
1356                         const char *autostash =
1357                                 state_dir_path("autostash", &options);
1358                         struct child_process stash = CHILD_PROCESS_INIT;
1359                         struct object_id oid;
1360                         struct commit *head =
1361                                 lookup_commit_reference(the_repository,
1362                                                         &options.orig_head);
1363
1364                         argv_array_pushl(&stash.args,
1365                                          "stash", "create", "autostash", NULL);
1366                         stash.git_cmd = 1;
1367                         stash.no_stdin = 1;
1368                         strbuf_reset(&buf);
1369                         if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
1370                                 die(_("Cannot autostash"));
1371                         strbuf_trim_trailing_newline(&buf);
1372                         if (get_oid(buf.buf, &oid))
1373                                 die(_("Unexpected stash response: '%s'"),
1374                                     buf.buf);
1375                         strbuf_reset(&buf);
1376                         strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
1377
1378                         if (safe_create_leading_directories_const(autostash))
1379                                 die(_("Could not create directory for '%s'"),
1380                                     options.state_dir);
1381                         write_file(autostash, "%s", oid_to_hex(&oid));
1382                         printf(_("Created autostash: %s\n"), buf.buf);
1383                         if (reset_head(&head->object.oid, "reset --hard",
1384                                        NULL, 0, NULL, NULL) < 0)
1385                                 die(_("could not reset --hard"));
1386                         printf(_("HEAD is now at %s"),
1387                                find_unique_abbrev(&head->object.oid,
1388                                                   DEFAULT_ABBREV));
1389                         strbuf_reset(&buf);
1390                         pp_commit_easy(CMIT_FMT_ONELINE, head, &buf);
1391                         if (buf.len > 0)
1392                                 printf(" %s", buf.buf);
1393                         putchar('\n');
1394
1395                         if (discard_index(the_repository->index) < 0 ||
1396                                 read_index(the_repository->index) < 0)
1397                                 die(_("could not read index"));
1398                 }
1399         }
1400
1401         if (require_clean_work_tree(the_repository, "rebase",
1402                                     _("Please commit or stash them."), 1, 1)) {
1403                 ret = 1;
1404                 goto cleanup;
1405         }
1406
1407         /*
1408          * Now we are rebasing commits upstream..orig_head (or with --root,
1409          * everything leading up to orig_head) on top of onto.
1410          */
1411
1412         /*
1413          * Check if we are already based on onto with linear history,
1414          * but this should be done only when upstream and onto are the same
1415          * and if this is not an interactive rebase.
1416          */
1417         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
1418             !is_interactive(&options) && !options.restrict_revision &&
1419             options.upstream &&
1420             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
1421                 int flag;
1422
1423                 if (!(options.flags & REBASE_FORCE)) {
1424                         /* Lazily switch to the target branch if needed... */
1425                         if (options.switch_to) {
1426                                 struct object_id oid;
1427
1428                                 if (get_oid(options.switch_to, &oid) < 0) {
1429                                         ret = !!error(_("could not parse '%s'"),
1430                                                       options.switch_to);
1431                                         goto cleanup;
1432                                 }
1433
1434                                 strbuf_reset(&buf);
1435                                 strbuf_addf(&buf, "rebase: checkout %s",
1436                                             options.switch_to);
1437                                 if (reset_head(&oid, "checkout",
1438                                                options.head_name, 0,
1439                                                NULL, NULL) < 0) {
1440                                         ret = !!error(_("could not switch to "
1441                                                         "%s"),
1442                                                       options.switch_to);
1443                                         goto cleanup;
1444                                 }
1445                         }
1446
1447                         if (!(options.flags & REBASE_NO_QUIET))
1448                                 ; /* be quiet */
1449                         else if (!strcmp(branch_name, "HEAD") &&
1450                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1451                                 puts(_("HEAD is up to date."));
1452                         else
1453                                 printf(_("Current branch %s is up to date.\n"),
1454                                        branch_name);
1455                         ret = !!finish_rebase(&options);
1456                         goto cleanup;
1457                 } else if (!(options.flags & REBASE_NO_QUIET))
1458                         ; /* be quiet */
1459                 else if (!strcmp(branch_name, "HEAD") &&
1460                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1461                         puts(_("HEAD is up to date, rebase forced."));
1462                 else
1463                         printf(_("Current branch %s is up to date, rebase "
1464                                  "forced.\n"), branch_name);
1465         }
1466
1467         /* If a hook exists, give it a chance to interrupt*/
1468         if (!ok_to_skip_pre_rebase &&
1469             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
1470                         argc ? argv[0] : NULL, NULL))
1471                 die(_("The pre-rebase hook refused to rebase."));
1472
1473         if (options.flags & REBASE_DIFFSTAT) {
1474                 struct diff_options opts;
1475
1476                 if (options.flags & REBASE_VERBOSE)
1477                         printf(_("Changes from %s to %s:\n"),
1478                                 oid_to_hex(&merge_base),
1479                                 oid_to_hex(&options.onto->object.oid));
1480
1481                 /* We want color (if set), but no pager */
1482                 diff_setup(&opts);
1483                 opts.stat_width = -1; /* use full terminal width */
1484                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
1485                 opts.output_format |=
1486                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
1487                 opts.detect_rename = DIFF_DETECT_RENAME;
1488                 diff_setup_done(&opts);
1489                 diff_tree_oid(&merge_base, &options.onto->object.oid,
1490                               "", &opts);
1491                 diffcore_std(&opts);
1492                 diff_flush(&opts);
1493         }
1494
1495         if (is_interactive(&options))
1496                 goto run_rebase;
1497
1498         /* Detach HEAD and reset the tree */
1499         if (options.flags & REBASE_NO_QUIET)
1500                 printf(_("First, rewinding head to replay your work on top of "
1501                          "it...\n"));
1502
1503         strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
1504         if (reset_head(&options.onto->object.oid, "checkout", NULL, 1,
1505             NULL, msg.buf))
1506                 die(_("Could not detach HEAD"));
1507         strbuf_release(&msg);
1508
1509         /*
1510          * If the onto is a proper descendant of the tip of the branch, then
1511          * we just fast-forwarded.
1512          */
1513         strbuf_reset(&msg);
1514         if (!oidcmp(&merge_base, &options.orig_head)) {
1515                 printf(_("Fast-forwarded %s to %s. \n"),
1516                         branch_name, options.onto_name);
1517                 strbuf_addf(&msg, "rebase finished: %s onto %s",
1518                         options.head_name ? options.head_name : "detached HEAD",
1519                         oid_to_hex(&options.onto->object.oid));
1520                 reset_head(NULL, "Fast-forwarded", options.head_name, 0,
1521                            "HEAD", msg.buf);
1522                 strbuf_release(&msg);
1523                 ret = !!finish_rebase(&options);
1524                 goto cleanup;
1525         }
1526
1527         strbuf_addf(&revisions, "%s..%s",
1528                     options.root ? oid_to_hex(&options.onto->object.oid) :
1529                     (options.restrict_revision ?
1530                      oid_to_hex(&options.restrict_revision->object.oid) :
1531                      oid_to_hex(&options.upstream->object.oid)),
1532                     oid_to_hex(&options.orig_head));
1533
1534         options.revisions = revisions.buf;
1535
1536 run_rebase:
1537         ret = !!run_specific_rebase(&options);
1538
1539 cleanup:
1540         strbuf_release(&revisions);
1541         free(options.head_name);
1542         free(options.gpg_sign_opt);
1543         free(options.cmd);
1544         free(squash_onto_name);
1545         return ret;
1546 }