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