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