builtin/rebase.c

   1 /*
   2  * "git rebase" builtin command
   3  *
   4  * Copyright (c) 2018 Pratik Karki
   5  */
   6
   7 #include "builtin.h"
   8 #include "run-command.h"
   9 #include "exec-cmd.h"
  10 #include "argv-array.h"
  11 #include "dir.h"
  12 #include "packfile.h"
  13 #include "refs.h"
  14 #include "quote.h"
  15 #include "config.h"
  16 #include "cache-tree.h"
  17 #include "unpack-trees.h"
  18 #include "lockfile.h"
  19 #include "parse-options.h"
  20 #include "commit.h"
  21 #include "diff.h"
  22 #include "wt-status.h"
  23 #include "revision.h"
  24 #include "commit-reach.h"
  25 #include "rerere.h"
  26
  27 static char const * const builtin_rebase_usage[] = {
  28         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  29                 "[<upstream>] [<branch>]"),
  30         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  31                 "--root [<branch>]"),
  32         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  33         NULL
  34 };
  35
  36 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  37 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  38
  39 enum rebase_type {
  40         REBASE_UNSPECIFIED = -1,
  41         REBASE_AM,
  42         REBASE_MERGE,
  43         REBASE_INTERACTIVE,
  44         REBASE_PRESERVE_MERGES
  45 };
  46
  47 static int use_builtin_rebase(void)
  48 {
  49         struct child_process cp = CHILD_PROCESS_INIT;
  50         struct strbuf out = STRBUF_INIT;
  51         int ret;
  52
  53         argv_array_pushl(&cp.args,
  54                          "config", "--bool", "rebase.usebuiltin", NULL);
  55         cp.git_cmd = 1;
  56         if (capture_command(&cp, &out, 6)) {
  57                 strbuf_release(&out);
  58                 return 1;
  59         }
  60
  61         strbuf_trim(&out);
  62         ret = !strcmp("true", out.buf);
  63         strbuf_release(&out);
  64         return ret;
  65 }
  66
  67 struct rebase_options {
  68         enum rebase_type type;
  69         const char *state_dir;
  70         struct commit *upstream;
  71         const char *upstream_name;
  72         const char *upstream_arg;
  73         char *head_name;
  74         struct object_id orig_head;
  75         struct commit *onto;
  76         const char *onto_name;
  77         const char *revisions;
  78         const char *switch_to;
  79         int root;
  80         struct object_id *squash_onto;
  81         struct commit *restrict_revision;
  82         int dont_finish_rebase;
  83         enum {
  84                 REBASE_NO_QUIET = 1<<0,
  85                 REBASE_VERBOSE = 1<<1,
  86                 REBASE_DIFFSTAT = 1<<2,
  87                 REBASE_FORCE = 1<<3,
  88                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  89         } flags;
  90         struct strbuf git_am_opt;
  91         const char *action;
  92         int signoff;
  93         int allow_rerere_autoupdate;
  94         int keep_empty;
  95         int autosquash;
  96         char *gpg_sign_opt;
  97         int autostash;
  98         char *cmd;
  99         int allow_empty_message;
 100         int rebase_merges, rebase_cousins;
 101         char *strategy, *strategy_opts;
 102         struct strbuf git_format_patch_opt;
 103 };
 104
 105 static int is_interactive(struct rebase_options *opts)
 106 {
 107         return opts->type == REBASE_INTERACTIVE ||
 108                 opts->type == REBASE_PRESERVE_MERGES;
 109 }
 110
 111 static void imply_interactive(struct rebase_options *opts, const char *option)
 112 {
 113         switch (opts->type) {
 114         case REBASE_AM:
 115                 die(_("%s requires an interactive rebase"), option);
 116                 break;
 117         case REBASE_INTERACTIVE:
 118         case REBASE_PRESERVE_MERGES:
 119                 break;
 120         case REBASE_MERGE:
 121                 /* we silently *upgrade* --merge to --interactive if needed */
 122         default:
 123                 opts->type = REBASE_INTERACTIVE; /* implied */
 124                 break;
 125         }
 126 }
 127
 128 /* Returns the filename prefixed by the state_dir */
 129 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 130 {
 131         static struct strbuf path = STRBUF_INIT;
 132         static size_t prefix_len;
 133
 134         if (!prefix_len) {
 135                 strbuf_addf(&path, "%s/", opts->state_dir);
 136                 prefix_len = path.len;
 137         }
 138
 139         strbuf_setlen(&path, prefix_len);
 140         strbuf_addstr(&path, filename);
 141         return path.buf;
 142 }
 143
 144 /* Read one file, then strip line endings */
 145 static int read_one(const char *path, struct strbuf *buf)
 146 {
 147         if (strbuf_read_file(buf, path, 0) < 0)
 148                 return error_errno(_("could not read '%s'"), path);
 149         strbuf_trim_trailing_newline(buf);
 150         return 0;
 151 }
 152
 153 /* Initialize the rebase options from the state directory. */
 154 static int read_basic_state(struct rebase_options *opts)
 155 {
 156         struct strbuf head_name = STRBUF_INIT;
 157         struct strbuf buf = STRBUF_INIT;
 158         struct object_id oid;
 159
 160         if (read_one(state_dir_path("head-name", opts), &head_name) ||
 161             read_one(state_dir_path("onto", opts), &buf))
 162                 return -1;
 163         opts->head_name = starts_with(head_name.buf, "refs/") ?
 164                 xstrdup(head_name.buf) : NULL;
 165         strbuf_release(&head_name);
 166         if (get_oid(buf.buf, &oid))
 167                 return error(_("could not get 'onto': '%s'"), buf.buf);
 168         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 169
 170         /*
 171          * We always write to orig-head, but interactive rebase used to write to
 172          * head. Fall back to reading from head to cover for the case that the
 173          * user upgraded git with an ongoing interactive rebase.
 174          */
 175         strbuf_reset(&buf);
 176         if (file_exists(state_dir_path("orig-head", opts))) {
 177                 if (read_one(state_dir_path("orig-head", opts), &buf))
 178                         return -1;
 179         } else if (read_one(state_dir_path("head", opts), &buf))
 180                 return -1;
 181         if (get_oid(buf.buf, &opts->orig_head))
 182                 return error(_("invalid orig-head: '%s'"), buf.buf);
 183
 184         strbuf_reset(&buf);
 185         if (read_one(state_dir_path("quiet", opts), &buf))
 186                 return -1;
 187         if (buf.len)
 188                 opts->flags &= ~REBASE_NO_QUIET;
 189         else
 190                 opts->flags |= REBASE_NO_QUIET;
 191
 192         if (file_exists(state_dir_path("verbose", opts)))
 193                 opts->flags |= REBASE_VERBOSE;
 194
 195         if (file_exists(state_dir_path("signoff", opts))) {
 196                 opts->signoff = 1;
 197                 opts->flags |= REBASE_FORCE;
 198         }
 199
 200         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 201                 strbuf_reset(&buf);
 202                 if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
 203                             &buf))
 204                         return -1;
 205                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
 206                         opts->allow_rerere_autoupdate = 1;
 207                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 208                         opts->allow_rerere_autoupdate = 0;
 209                 else
 210                         warning(_("ignoring invalid allow_rerere_autoupdate: "
 211                                   "'%s'"), buf.buf);
 212         } else
 213                 opts->allow_rerere_autoupdate = -1;
 214
 215         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 216                 strbuf_reset(&buf);
 217                 if (read_one(state_dir_path("gpg_sign_opt", opts),
 218                             &buf))
 219                         return -1;
 220                 free(opts->gpg_sign_opt);
 221                 opts->gpg_sign_opt = xstrdup(buf.buf);
 222         }
 223
 224         if (file_exists(state_dir_path("strategy", opts))) {
 225                 strbuf_reset(&buf);
 226                 if (read_one(state_dir_path("strategy", opts), &buf))
 227                         return -1;
 228                 free(opts->strategy);
 229                 opts->strategy = xstrdup(buf.buf);
 230         }
 231
 232         if (file_exists(state_dir_path("strategy_opts", opts))) {
 233                 strbuf_reset(&buf);
 234                 if (read_one(state_dir_path("strategy_opts", opts), &buf))
 235                         return -1;
 236                 free(opts->strategy_opts);
 237                 opts->strategy_opts = xstrdup(buf.buf);
 238         }
 239
 240         strbuf_release(&buf);
 241
 242         return 0;
 243 }
 244
 245 static int apply_autostash(struct rebase_options *opts)
 246 {
 247         const char *path = state_dir_path("autostash", opts);
 248         struct strbuf autostash = STRBUF_INIT;
 249         struct child_process stash_apply = CHILD_PROCESS_INIT;
 250
 251         if (!file_exists(path))
 252                 return 0;
 253
 254         if (read_one(path, &autostash))
 255                 return error(_("Could not read '%s'"), path);
 256         /* Ensure that the hash is not mistaken for a number */
 257         strbuf_addstr(&autostash, "^0");
 258         argv_array_pushl(&stash_apply.args,
 259                          "stash", "apply", autostash.buf, NULL);
 260         stash_apply.git_cmd = 1;
 261         stash_apply.no_stderr = stash_apply.no_stdout =
 262                 stash_apply.no_stdin = 1;
 263         if (!run_command(&stash_apply))
 264                 printf(_("Applied autostash.\n"));
 265         else {
 266                 struct argv_array args = ARGV_ARRAY_INIT;
 267                 int res = 0;
 268
 269                 argv_array_pushl(&args,
 270                                  "stash", "store", "-m", "autostash", "-q",
 271                                  autostash.buf, NULL);
 272                 if (run_command_v_opt(args.argv, RUN_GIT_CMD))
 273                         res = error(_("Cannot store %s"), autostash.buf);
 274                 argv_array_clear(&args);
 275                 strbuf_release(&autostash);
 276                 if (res)
 277                         return res;
 278
 279                 fprintf(stderr,
 280                         _("Applying autostash resulted in conflicts.\n"
 281                           "Your changes are safe in the stash.\n"
 282                           "You can run \"git stash pop\" or \"git stash drop\" "
 283                           "at any time.\n"));
 284         }
 285
 286         strbuf_release(&autostash);
 287         return 0;
 288 }
 289
 290 static int finish_rebase(struct rebase_options *opts)
 291 {
 292         struct strbuf dir = STRBUF_INIT;
 293         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 294
 295         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 296         apply_autostash(opts);
 297         close_all_packs(the_repository->objects);
 298         /*
 299          * We ignore errors in 'gc --auto', since the
 300          * user should see them.
 301          */
 302         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 303         strbuf_addstr(&dir, opts->state_dir);
 304         remove_dir_recursively(&dir, 0);
 305         strbuf_release(&dir);
 306
 307         return 0;
 308 }
 309
 310 static struct commit *peel_committish(const char *name)
 311 {
 312         struct object *obj;
 313         struct object_id oid;
 314
 315         if (get_oid(name, &oid))
 316                 return NULL;
 317         obj = parse_object(the_repository, &oid);
 318         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 319 }
 320
 321 static void add_var(struct strbuf *buf, const char *name, const char *value)
 322 {
 323         if (!value)
 324                 strbuf_addf(buf, "unset %s; ", name);
 325         else {
 326                 strbuf_addf(buf, "%s=", name);
 327                 sq_quote_buf(buf, value);
 328                 strbuf_addstr(buf, "; ");
 329         }
 330 }
 331
 332 static const char *resolvemsg =
 333 N_("Resolve all conflicts manually, mark them as resolved with\n"
 334 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 335 "You can instead skip this commit: run \"git rebase --skip\".\n"
 336 "To abort and get back to the state before \"git rebase\", run "
 337 "\"git rebase --abort\".");
 338
 339 static int run_specific_rebase(struct rebase_options *opts)
 340 {
 341         const char *argv[] = { NULL, NULL };
 342         struct strbuf script_snippet = STRBUF_INIT;
 343         int status;
 344         const char *backend, *backend_func;
 345
 346         if (opts->type == REBASE_INTERACTIVE) {
 347                 /* Run builtin interactive rebase */
 348                 struct child_process child = CHILD_PROCESS_INIT;
 349
 350                 argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
 351                                  resolvemsg);
 352                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 353                         argv_array_push(&child.env_array, "GIT_EDITOR=:");
 354                         opts->autosquash = 0;
 355                 }
 356
 357                 child.git_cmd = 1;
 358                 argv_array_push(&child.args, "rebase--interactive");
 359
 360                 if (opts->action)
 361                         argv_array_pushf(&child.args, "--%s", opts->action);
 362                 if (opts->keep_empty)
 363                         argv_array_push(&child.args, "--keep-empty");
 364                 if (opts->rebase_merges)
 365                         argv_array_push(&child.args, "--rebase-merges");
 366                 if (opts->rebase_cousins)
 367                         argv_array_push(&child.args, "--rebase-cousins");
 368                 if (opts->autosquash)
 369                         argv_array_push(&child.args, "--autosquash");
 370                 if (opts->flags & REBASE_VERBOSE)
 371                         argv_array_push(&child.args, "--verbose");
 372                 if (opts->flags & REBASE_FORCE)
 373                         argv_array_push(&child.args, "--no-ff");
 374                 if (opts->restrict_revision)
 375                         argv_array_pushf(&child.args,
 376                                          "--restrict-revision=^%s",
 377                                          oid_to_hex(&opts->restrict_revision->object.oid));
 378                 if (opts->upstream)
 379                         argv_array_pushf(&child.args, "--upstream=%s",
 380                                          oid_to_hex(&opts->upstream->object.oid));
 381                 if (opts->onto)
 382                         argv_array_pushf(&child.args, "--onto=%s",
 383                                          oid_to_hex(&opts->onto->object.oid));
 384                 if (opts->squash_onto)
 385                         argv_array_pushf(&child.args, "--squash-onto=%s",
 386                                          oid_to_hex(opts->squash_onto));
 387                 if (opts->onto_name)
 388                         argv_array_pushf(&child.args, "--onto-name=%s",
 389                                          opts->onto_name);
 390                 argv_array_pushf(&child.args, "--head-name=%s",
 391                                  opts->head_name ?
 392                                  opts->head_name : "detached HEAD");
 393                 if (opts->strategy)
 394                         argv_array_pushf(&child.args, "--strategy=%s",
 395                                          opts->strategy);
 396                 if (opts->strategy_opts)
 397                         argv_array_pushf(&child.args, "--strategy-opts=%s",
 398                                          opts->strategy_opts);
 399                 if (opts->switch_to)
 400                         argv_array_pushf(&child.args, "--switch-to=%s",
 401                                          opts->switch_to);
 402                 if (opts->cmd)
 403                         argv_array_pushf(&child.args, "--cmd=%s", opts->cmd);
 404                 if (opts->allow_empty_message)
 405                         argv_array_push(&child.args, "--allow-empty-message");
 406                 if (opts->allow_rerere_autoupdate > 0)
 407                         argv_array_push(&child.args, "--rerere-autoupdate");
 408                 else if (opts->allow_rerere_autoupdate == 0)
 409                         argv_array_push(&child.args, "--no-rerere-autoupdate");
 410                 if (opts->gpg_sign_opt)
 411                         argv_array_push(&child.args, opts->gpg_sign_opt);
 412                 if (opts->signoff)
 413                         argv_array_push(&child.args, "--signoff");
 414
 415                 status = run_command(&child);
 416                 goto finished_rebase;
 417         }
 418
 419         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 420         add_var(&script_snippet, "state_dir", opts->state_dir);
 421
 422         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 423         add_var(&script_snippet, "upstream", opts->upstream ?
 424                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 425         add_var(&script_snippet, "head_name",
 426                 opts->head_name ? opts->head_name : "detached HEAD");
 427         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 428         add_var(&script_snippet, "onto", opts->onto ?
 429                 oid_to_hex(&opts->onto->object.oid) : NULL);
 430         add_var(&script_snippet, "onto_name", opts->onto_name);
 431         add_var(&script_snippet, "revisions", opts->revisions);
 432         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 433                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 434         add_var(&script_snippet, "GIT_QUIET",
 435                 opts->flags & REBASE_NO_QUIET ? "" : "t");
 436         add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 437         add_var(&script_snippet, "verbose",
 438                 opts->flags & REBASE_VERBOSE ? "t" : "");
 439         add_var(&script_snippet, "diffstat",
 440                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 441         add_var(&script_snippet, "force_rebase",
 442                 opts->flags & REBASE_FORCE ? "t" : "");
 443         if (opts->switch_to)
 444                 add_var(&script_snippet, "switch_to", opts->switch_to);
 445         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 446         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 447         add_var(&script_snippet, "allow_rerere_autoupdate",
 448                 opts->allow_rerere_autoupdate < 0 ? "" :
 449                 opts->allow_rerere_autoupdate ?
 450                 "--rerere-autoupdate" : "--no-rerere-autoupdate");
 451         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 452         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 453         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 454         add_var(&script_snippet, "cmd", opts->cmd);
 455         add_var(&script_snippet, "allow_empty_message",
 456                 opts->allow_empty_message ?  "--allow-empty-message" : "");
 457         add_var(&script_snippet, "rebase_merges",
 458                 opts->rebase_merges ? "t" : "");
 459         add_var(&script_snippet, "rebase_cousins",
 460                 opts->rebase_cousins ? "t" : "");
 461         add_var(&script_snippet, "strategy", opts->strategy);
 462         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
 463         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
 464         add_var(&script_snippet, "squash_onto",
 465                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
 466         add_var(&script_snippet, "git_format_patch_opt",
 467                 opts->git_format_patch_opt.buf);
 468
 469         if (is_interactive(opts) &&
 470             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 471                 strbuf_addstr(&script_snippet,
 472                               "GIT_EDITOR=:; export GIT_EDITOR; ");
 473                 opts->autosquash = 0;
 474         }
 475
 476         switch (opts->type) {
 477         case REBASE_AM:
 478                 backend = "git-rebase--am";
 479                 backend_func = "git_rebase__am";
 480                 break;
 481         case REBASE_MERGE:
 482                 backend = "git-rebase--merge";
 483                 backend_func = "git_rebase__merge";
 484                 break;
 485         case REBASE_PRESERVE_MERGES:
 486                 backend = "git-rebase--preserve-merges";
 487                 backend_func = "git_rebase__preserve_merges";
 488                 break;
 489         default:
 490                 BUG("Unhandled rebase type %d", opts->type);
 491                 break;
 492         }
 493
 494         strbuf_addf(&script_snippet,
 495                     ". git-sh-setup && . git-rebase--common &&"
 496                     " . %s && %s", backend, backend_func);
 497         argv[0] = script_snippet.buf;
 498
 499         status = run_command_v_opt(argv, RUN_USING_SHELL);
 500 finished_rebase:
 501         if (opts->dont_finish_rebase)
 502                 ; /* do nothing */
 503         else if (opts->type == REBASE_INTERACTIVE)
 504                 ; /* interactive rebase cleans up after itself */
 505         else if (status == 0) {
 506                 if (!file_exists(state_dir_path("stopped-sha", opts)))
 507                         finish_rebase(opts);
 508         } else if (status == 2) {
 509                 struct strbuf dir = STRBUF_INIT;
 510
 511                 apply_autostash(opts);
 512                 strbuf_addstr(&dir, opts->state_dir);
 513                 remove_dir_recursively(&dir, 0);
 514                 strbuf_release(&dir);
 515                 die("Nothing to do");
 516         }
 517
 518         strbuf_release(&script_snippet);
 519
 520         return status ? -1 : 0;
 521 }
 522
 523 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 524
 525 #define RESET_HEAD_DETACH (1<<0)
 526 #define RESET_HEAD_HARD (1<<1)
 527
 528 static int reset_head(struct object_id *oid, const char *action,
 529                       const char *switch_to_branch, unsigned flags,
 530                       const char *reflog_orig_head, const char *reflog_head)
 531 {
 532         unsigned detach_head = flags & RESET_HEAD_DETACH;
 533         unsigned reset_hard = flags & RESET_HEAD_HARD;
 534         struct object_id head_oid;
 535         struct tree_desc desc[2] = { { NULL }, { NULL } };
 536         struct lock_file lock = LOCK_INIT;
 537         struct unpack_trees_options unpack_tree_opts;
 538         struct tree *tree;
 539         const char *reflog_action;
 540         struct strbuf msg = STRBUF_INIT;
 541         size_t prefix_len;
 542         struct object_id *orig = NULL, oid_orig,
 543                 *old_orig = NULL, oid_old_orig;
 544         int ret = 0, nr = 0;
 545
 546         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 547                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 548
 549         if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
 550                 ret = -1;
 551                 goto leave_reset_head;
 552         }
 553
 554         if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
 555                 ret = error(_("could not determine HEAD revision"));
 556                 goto leave_reset_head;
 557         }
 558
 559         if (!oid)
 560                 oid = &head_oid;
 561
 562         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 563         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 564         unpack_tree_opts.head_idx = 1;
 565         unpack_tree_opts.src_index = the_repository->index;
 566         unpack_tree_opts.dst_index = the_repository->index;
 567         unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
 568         unpack_tree_opts.update = 1;
 569         unpack_tree_opts.merge = 1;
 570         if (!detach_head)
 571                 unpack_tree_opts.reset = 1;
 572
 573         if (read_index_unmerged(the_repository->index) < 0) {
 574                 ret = error(_("could not read index"));
 575                 goto leave_reset_head;
 576         }
 577
 578         if (!reset_hard && !fill_tree_descriptor(&desc[nr++], &head_oid)) {
 579                 ret = error(_("failed to find tree of %s"),
 580                             oid_to_hex(&head_oid));
 581                 goto leave_reset_head;
 582         }
 583
 584         if (!fill_tree_descriptor(&desc[nr++], oid)) {
 585                 ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
 586                 goto leave_reset_head;
 587         }
 588
 589         if (unpack_trees(nr, desc, &unpack_tree_opts)) {
 590                 ret = -1;
 591                 goto leave_reset_head;
 592         }
 593
 594         tree = parse_tree_indirect(oid);
 595         prime_cache_tree(the_repository->index, tree);
 596
 597         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
 598                 ret = error(_("could not write index"));
 599                 goto leave_reset_head;
 600         }
 601
 602         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 603         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 604         prefix_len = msg.len;
 605
 606         if (!get_oid("ORIG_HEAD", &oid_old_orig))
 607                 old_orig = &oid_old_orig;
 608         if (!get_oid("HEAD", &oid_orig)) {
 609                 orig = &oid_orig;
 610                 if (!reflog_orig_head) {
 611                         strbuf_addstr(&msg, "updating ORIG_HEAD");
 612                         reflog_orig_head = msg.buf;
 613                 }
 614                 update_ref(reflog_orig_head, "ORIG_HEAD", orig, old_orig, 0,
 615                            UPDATE_REFS_MSG_ON_ERR);
 616         } else if (old_orig)
 617                 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 618         if (!reflog_head) {
 619                 strbuf_setlen(&msg, prefix_len);
 620                 strbuf_addstr(&msg, "updating HEAD");
 621                 reflog_head = msg.buf;
 622         }
 623         if (!switch_to_branch)
 624                 ret = update_ref(reflog_head, "HEAD", oid, orig, REF_NO_DEREF,
 625                                  UPDATE_REFS_MSG_ON_ERR);
 626         else {
 627                 ret = create_symref("HEAD", switch_to_branch, msg.buf);
 628                 if (!ret)
 629                         ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
 630                                          UPDATE_REFS_MSG_ON_ERR);
 631         }
 632
 633 leave_reset_head:
 634         strbuf_release(&msg);
 635         rollback_lock_file(&lock);
 636         while (nr)
 637                 free((void *)desc[--nr].buffer);
 638         return ret;
 639 }
 640
 641 static int rebase_config(const char *var, const char *value, void *data)
 642 {
 643         struct rebase_options *opts = data;
 644
 645         if (!strcmp(var, "rebase.stat")) {
 646                 if (git_config_bool(var, value))
 647                         opts->flags |= REBASE_DIFFSTAT;
 648                 else
 649                         opts->flags &= !REBASE_DIFFSTAT;
 650                 return 0;
 651         }
 652
 653         if (!strcmp(var, "rebase.autosquash")) {
 654                 opts->autosquash = git_config_bool(var, value);
 655                 return 0;
 656         }
 657
 658         if (!strcmp(var, "commit.gpgsign")) {
 659                 free(opts->gpg_sign_opt);
 660                 opts->gpg_sign_opt = git_config_bool(var, value) ?
 661                         xstrdup("-S") : NULL;
 662                 return 0;
 663         }
 664
 665         if (!strcmp(var, "rebase.autostash")) {
 666                 opts->autostash = git_config_bool(var, value);
 667                 return 0;
 668         }
 669
 670         return git_default_config(var, value, data);
 671 }
 672
 673 /*
 674  * Determines whether the commits in from..to are linear, i.e. contain
 675  * no merge commits. This function *expects* `from` to be an ancestor of
 676  * `to`.
 677  */
 678 static int is_linear_history(struct commit *from, struct commit *to)
 679 {
 680         while (to && to != from) {
 681                 parse_commit(to);
 682                 if (!to->parents)
 683                         return 1;
 684                 if (to->parents->next)
 685                         return 0;
 686                 to = to->parents->item;
 687         }
 688         return 1;
 689 }
 690
 691 static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 692                             struct object_id *merge_base)
 693 {
 694         struct commit *head = lookup_commit(the_repository, head_oid);
 695         struct commit_list *merge_bases;
 696         int res;
 697
 698         if (!head)
 699                 return 0;
 700
 701         merge_bases = get_merge_bases(onto, head);
 702         if (merge_bases && !merge_bases->next) {
 703                 oidcpy(merge_base, &merge_bases->item->object.oid);
 704                 res = oideq(merge_base, &onto->object.oid);
 705         } else {
 706                 oidcpy(merge_base, &null_oid);
 707                 res = 0;
 708         }
 709         free_commit_list(merge_bases);
 710         return res && is_linear_history(onto, head);
 711 }
 712
 713 /* -i followed by -m is still -i */
 714 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 715 {
 716         struct rebase_options *opts = opt->value;
 717
 718         if (!is_interactive(opts))
 719                 opts->type = REBASE_MERGE;
 720
 721         return 0;
 722 }
 723
 724 /* -i followed by -p is still explicitly interactive, but -p alone is not */
 725 static int parse_opt_interactive(const struct option *opt, const char *arg,
 726                                  int unset)
 727 {
 728         struct rebase_options *opts = opt->value;
 729
 730         opts->type = REBASE_INTERACTIVE;
 731         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 732
 733         return 0;
 734 }
 735
 736 static void NORETURN error_on_missing_default_upstream(void)
 737 {
 738         struct branch *current_branch = branch_get(NULL);
 739
 740         printf(_("%s\n"
 741                  "Please specify which branch you want to rebase against.\n"
 742                  "See git-rebase(1) for details.\n"
 743                  "\n"
 744                  "    git rebase '<branch>'\n"
 745                  "\n"),
 746                 current_branch ? _("There is no tracking information for "
 747                         "the current branch.") :
 748                         _("You are not currently on a branch."));
 749
 750         if (current_branch) {
 751                 const char *remote = current_branch->remote_name;
 752
 753                 if (!remote)
 754                         remote = _("<remote>");
 755
 756                 printf(_("If you wish to set tracking information for this "
 757                          "branch you can do so with:\n"
 758                          "\n"
 759                          "    git branch --set-upstream-to=%s/<branch> %s\n"
 760                          "\n"),
 761                        remote, current_branch->name);
 762         }
 763         exit(1);
 764 }
 765
 766 int cmd_rebase(int argc, const char **argv, const char *prefix)
 767 {
 768         struct rebase_options options = {
 769                 .type = REBASE_UNSPECIFIED,
 770                 .flags = REBASE_NO_QUIET,
 771                 .git_am_opt = STRBUF_INIT,
 772                 .allow_rerere_autoupdate  = -1,
 773                 .allow_empty_message = 1,
 774                 .git_format_patch_opt = STRBUF_INIT,
 775         };
 776         const char *branch_name;
 777         int ret, flags, total_argc, in_progress = 0;
 778         int ok_to_skip_pre_rebase = 0;
 779         struct strbuf msg = STRBUF_INIT;
 780         struct strbuf revisions = STRBUF_INIT;
 781         struct strbuf buf = STRBUF_INIT;
 782         struct object_id merge_base;
 783         enum {
 784                 NO_ACTION,
 785                 ACTION_CONTINUE,
 786                 ACTION_SKIP,
 787                 ACTION_ABORT,
 788                 ACTION_QUIT,
 789                 ACTION_EDIT_TODO,
 790                 ACTION_SHOW_CURRENT_PATCH,
 791         } action = NO_ACTION;
 792         int committer_date_is_author_date = 0;
 793         int ignore_date = 0;
 794         int ignore_whitespace = 0;
 795         const char *gpg_sign = NULL;
 796         int opt_c = -1;
 797         struct string_list whitespace = STRING_LIST_INIT_NODUP;
 798         struct string_list exec = STRING_LIST_INIT_NODUP;
 799         const char *rebase_merges = NULL;
 800         int fork_point = -1;
 801         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
 802         struct object_id squash_onto;
 803         char *squash_onto_name = NULL;
 804         struct option builtin_rebase_options[] = {
 805                 OPT_STRING(0, "onto", &options.onto_name,
 806                            N_("revision"),
 807                            N_("rebase onto given branch instead of upstream")),
 808                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 809                          N_("allow pre-rebase hook to run")),
 810                 OPT_NEGBIT('q', "quiet", &options.flags,
 811                            N_("be quiet. implies --no-stat"),
 812                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 813                 OPT_BIT('v', "verbose", &options.flags,
 814                         N_("display a diffstat of what changed upstream"),
 815                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 816                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 817                         N_("do not show diffstat of what changed upstream"),
 818                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 819                 OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
 820                          N_("passed to 'git apply'")),
 821                 OPT_BOOL(0, "signoff", &options.signoff,
 822                          N_("add a Signed-off-by: line to each commit")),
 823                 OPT_BOOL(0, "committer-date-is-author-date",
 824                          &committer_date_is_author_date,
 825                          N_("passed to 'git am'")),
 826                 OPT_BOOL(0, "ignore-date", &ignore_date,
 827                          N_("passed to 'git am'")),
 828                 OPT_BIT('f', "force-rebase", &options.flags,
 829                         N_("cherry-pick all commits, even if unchanged"),
 830                         REBASE_FORCE),
 831                 OPT_BIT(0, "no-ff", &options.flags,
 832                         N_("cherry-pick all commits, even if unchanged"),
 833                         REBASE_FORCE),
 834                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
 835                             ACTION_CONTINUE),
 836                 OPT_CMDMODE(0, "skip", &action,
 837                             N_("skip current patch and continue"), ACTION_SKIP),
 838                 OPT_CMDMODE(0, "abort", &action,
 839                             N_("abort and check out the original branch"),
 840                             ACTION_ABORT),
 841                 OPT_CMDMODE(0, "quit", &action,
 842                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
 843                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
 844                             "during an interactive rebase"), ACTION_EDIT_TODO),
 845                 OPT_CMDMODE(0, "show-current-patch", &action,
 846                             N_("show the patch file being applied or merged"),
 847                             ACTION_SHOW_CURRENT_PATCH),
 848                 { OPTION_CALLBACK, 'm', "merge", &options, NULL,
 849                         N_("use merging strategies to rebase"),
 850                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 851                         parse_opt_merge },
 852                 { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
 853                         N_("let the user edit the list of commits to rebase"),
 854                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 855                         parse_opt_interactive },
 856                 OPT_SET_INT('p', "preserve-merges", &options.type,
 857                             N_("try to recreate merges instead of ignoring "
 858                                "them"), REBASE_PRESERVE_MERGES),
 859                 OPT_BOOL(0, "rerere-autoupdate",
 860                          &options.allow_rerere_autoupdate,
 861                          N_("allow rerere to update index  with resolved "
 862                             "conflict")),
 863                 OPT_BOOL('k', "keep-empty", &options.keep_empty,
 864                          N_("preserve empty commits during rebase")),
 865                 OPT_BOOL(0, "autosquash", &options.autosquash,
 866                          N_("move commits that begin with "
 867                             "squash!/fixup! under -i")),
 868                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 869                         N_("GPG-sign commits"),
 870                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 871                 OPT_STRING_LIST(0, "whitespace", &whitespace,
 872                                 N_("whitespace"), N_("passed to 'git apply'")),
 873                 OPT_SET_INT('C', NULL, &opt_c, N_("passed to 'git apply'"),
 874                             REBASE_AM),
 875                 OPT_BOOL(0, "autostash", &options.autostash,
 876                          N_("automatically stash/stash pop before and after")),
 877                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
 878                                 N_("add exec lines after each commit of the "
 879                                    "editable list")),
 880                 OPT_BOOL(0, "allow-empty-message",
 881                          &options.allow_empty_message,
 882                          N_("allow rebasing commits with empty messages")),
 883                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
 884                         N_("mode"),
 885                         N_("try to rebase merges instead of skipping them"),
 886                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
 887                 OPT_BOOL(0, "fork-point", &fork_point,
 888                          N_("use 'merge-base --fork-point' to refine upstream")),
 889                 OPT_STRING('s', "strategy", &options.strategy,
 890                            N_("strategy"), N_("use the given merge strategy")),
 891                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
 892                                 N_("option"),
 893                                 N_("pass the argument through to the merge "
 894                                    "strategy")),
 895                 OPT_BOOL(0, "root", &options.root,
 896                          N_("rebase all reachable commits up to the root(s)")),
 897                 OPT_END(),
 898         };
 899
 900         /*
 901          * NEEDSWORK: Once the builtin rebase has been tested enough
 902          * and git-legacy-rebase.sh is retired to contrib/, this preamble
 903          * can be removed.
 904          */
 905
 906         if (!use_builtin_rebase()) {
 907                 const char *path = mkpath("%s/git-legacy-rebase",
 908                                           git_exec_path());
 909
 910                 if (sane_execvp(path, (char **)argv) < 0)
 911                         die_errno(_("could not exec %s"), path);
 912                 else
 913                         BUG("sane_execvp() returned???");
 914         }
 915
 916         if (argc == 2 && !strcmp(argv[1], "-h"))
 917                 usage_with_options(builtin_rebase_usage,
 918                                    builtin_rebase_options);
 919
 920         prefix = setup_git_directory();
 921         trace_repo_setup(prefix);
 922         setup_work_tree();
 923
 924         git_config(rebase_config, &options);
 925
 926         strbuf_reset(&buf);
 927         strbuf_addf(&buf, "%s/applying", apply_dir());
 928         if(file_exists(buf.buf))
 929                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
 930
 931         if (is_directory(apply_dir())) {
 932                 options.type = REBASE_AM;
 933                 options.state_dir = apply_dir();
 934         } else if (is_directory(merge_dir())) {
 935                 strbuf_reset(&buf);
 936                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
 937                 if (is_directory(buf.buf)) {
 938                         options.type = REBASE_PRESERVE_MERGES;
 939                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 940                 } else {
 941                         strbuf_reset(&buf);
 942                         strbuf_addf(&buf, "%s/interactive", merge_dir());
 943                         if(file_exists(buf.buf)) {
 944                                 options.type = REBASE_INTERACTIVE;
 945                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 946                         } else
 947                                 options.type = REBASE_MERGE;
 948                 }
 949                 options.state_dir = merge_dir();
 950         }
 951
 952         if (options.type != REBASE_UNSPECIFIED)
 953                 in_progress = 1;
 954
 955         total_argc = argc;
 956         argc = parse_options(argc, argv, prefix,
 957                              builtin_rebase_options,
 958                              builtin_rebase_usage, 0);
 959
 960         if (action != NO_ACTION && total_argc != 2) {
 961                 usage_with_options(builtin_rebase_usage,
 962                                    builtin_rebase_options);
 963         }
 964
 965         if (argc > 2)
 966                 usage_with_options(builtin_rebase_usage,
 967                                    builtin_rebase_options);
 968
 969         if (action != NO_ACTION && !in_progress)
 970                 die(_("No rebase in progress?"));
 971
 972         if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 973                 die(_("The --edit-todo action can only be used during "
 974                       "interactive rebase."));
 975
 976         switch (action) {
 977         case ACTION_CONTINUE: {
 978                 struct object_id head;
 979                 struct lock_file lock_file = LOCK_INIT;
 980                 int fd;
 981
 982                 options.action = "continue";
 983
 984                 /* Sanity check */
 985                 if (get_oid("HEAD", &head))
 986                         die(_("Cannot read HEAD"));
 987
 988                 fd = hold_locked_index(&lock_file, 0);
 989                 if (read_index(the_repository->index) < 0)
 990                         die(_("could not read index"));
 991                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 992                               NULL);
 993                 if (0 <= fd)
 994                         update_index_if_able(the_repository->index,
 995                                              &lock_file);
 996                 rollback_lock_file(&lock_file);
 997
 998                 if (has_unstaged_changes(1)) {
 999                         puts(_("You must edit all merge conflicts and then\n"
1000                                "mark them as resolved using git add"));
1001                         exit(1);
1002                 }
1003                 if (read_basic_state(&options))
1004                         exit(1);
1005                 goto run_rebase;
1006         }
1007         case ACTION_SKIP: {
1008                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1009
1010                 options.action = "skip";
1011
1012                 rerere_clear(&merge_rr);
1013                 string_list_clear(&merge_rr, 1);
1014
1015                 if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
1016                                NULL, NULL) < 0)
1017                         die(_("could not discard worktree changes"));
1018                 if (read_basic_state(&options))
1019                         exit(1);
1020                 goto run_rebase;
1021         }
1022         case ACTION_ABORT: {
1023                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1024                 options.action = "abort";
1025
1026                 rerere_clear(&merge_rr);
1027                 string_list_clear(&merge_rr, 1);
1028
1029                 if (read_basic_state(&options))
1030                         exit(1);
1031                 if (reset_head(&options.orig_head, "reset",
1032                                options.head_name, RESET_HEAD_HARD,
1033                                NULL, NULL) < 0)
1034                         die(_("could not move back to %s"),
1035                             oid_to_hex(&options.orig_head));
1036                 ret = finish_rebase(&options);
1037                 goto cleanup;
1038         }
1039         case ACTION_QUIT: {
1040                 strbuf_reset(&buf);
1041                 strbuf_addstr(&buf, options.state_dir);
1042                 ret = !!remove_dir_recursively(&buf, 0);
1043                 if (ret)
1044                         die(_("could not remove '%s'"), options.state_dir);
1045                 goto cleanup;
1046         }
1047         case ACTION_EDIT_TODO:
1048                 options.action = "edit-todo";
1049                 options.dont_finish_rebase = 1;
1050                 goto run_rebase;
1051         case ACTION_SHOW_CURRENT_PATCH:
1052                 options.action = "show-current-patch";
1053                 options.dont_finish_rebase = 1;
1054                 goto run_rebase;
1055         case NO_ACTION:
1056                 break;
1057         default:
1058                 BUG("action: %d", action);
1059         }
1060
1061         /* Make sure no rebase is in progress */
1062         if (in_progress) {
1063                 const char *last_slash = strrchr(options.state_dir, '/');
1064                 const char *state_dir_base =
1065                         last_slash ? last_slash + 1 : options.state_dir;
1066                 const char *cmd_live_rebase =
1067                         "git rebase (--continue | --abort | --skip)";
1068                 strbuf_reset(&buf);
1069                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1070                 die(_("It seems that there is already a %s directory, and\n"
1071                       "I wonder if you are in the middle of another rebase.  "
1072                       "If that is the\n"
1073                       "case, please try\n\t%s\n"
1074                       "If that is not the case, please\n\t%s\n"
1075                       "and run me again.  I am stopping in case you still "
1076                       "have something\n"
1077                       "valuable there.\n"),
1078                     state_dir_base, cmd_live_rebase, buf.buf);
1079         }
1080
1081         if (!(options.flags & REBASE_NO_QUIET))
1082                 strbuf_addstr(&options.git_am_opt, " -q");
1083
1084         if (committer_date_is_author_date) {
1085                 strbuf_addstr(&options.git_am_opt,
1086                               " --committer-date-is-author-date");
1087                 options.flags |= REBASE_FORCE;
1088         }
1089
1090         if (ignore_whitespace)
1091                 strbuf_addstr(&options.git_am_opt, " --ignore-whitespace");
1092
1093         if (ignore_date) {
1094                 strbuf_addstr(&options.git_am_opt, " --ignore-date");
1095                 options.flags |= REBASE_FORCE;
1096         }
1097
1098         if (options.keep_empty)
1099                 imply_interactive(&options, "--keep-empty");
1100
1101         if (gpg_sign) {
1102                 free(options.gpg_sign_opt);
1103                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1104         }
1105
1106         if (opt_c >= 0)
1107                 strbuf_addf(&options.git_am_opt, " -C%d", opt_c);
1108
1109         if (whitespace.nr) {
1110                 int i;
1111
1112                 for (i = 0; i < whitespace.nr; i++) {
1113                         const char *item = whitespace.items[i].string;
1114
1115                         strbuf_addf(&options.git_am_opt, " --whitespace=%s",
1116                                     item);
1117
1118                         if ((!strcmp(item, "fix")) || (!strcmp(item, "strip")))
1119                                 options.flags |= REBASE_FORCE;
1120                 }
1121         }
1122
1123         if (exec.nr) {
1124                 int i;
1125
1126                 imply_interactive(&options, "--exec");
1127
1128                 strbuf_reset(&buf);
1129                 for (i = 0; i < exec.nr; i++)
1130                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1131                 options.cmd = xstrdup(buf.buf);
1132         }
1133
1134         if (rebase_merges) {
1135                 if (!*rebase_merges)
1136                         ; /* default mode; do nothing */
1137                 else if (!strcmp("rebase-cousins", rebase_merges))
1138                         options.rebase_cousins = 1;
1139                 else if (strcmp("no-rebase-cousins", rebase_merges))
1140                         die(_("Unknown mode: %s"), rebase_merges);
1141                 options.rebase_merges = 1;
1142                 imply_interactive(&options, "--rebase-merges");
1143         }
1144
1145         if (strategy_options.nr) {
1146                 int i;
1147
1148                 if (!options.strategy)
1149                         options.strategy = "recursive";
1150
1151                 strbuf_reset(&buf);
1152                 for (i = 0; i < strategy_options.nr; i++)
1153                         strbuf_addf(&buf, " --%s",
1154                                     strategy_options.items[i].string);
1155                 options.strategy_opts = xstrdup(buf.buf);
1156         }
1157
1158         if (options.strategy) {
1159                 options.strategy = xstrdup(options.strategy);
1160                 switch (options.type) {
1161                 case REBASE_AM:
1162                         die(_("--strategy requires --merge or --interactive"));
1163                 case REBASE_MERGE:
1164                 case REBASE_INTERACTIVE:
1165                 case REBASE_PRESERVE_MERGES:
1166                         /* compatible */
1167                         break;
1168                 case REBASE_UNSPECIFIED:
1169                         options.type = REBASE_MERGE;
1170                         break;
1171                 default:
1172                         BUG("unhandled rebase type (%d)", options.type);
1173                 }
1174         }
1175
1176         if (options.root && !options.onto_name)
1177                 imply_interactive(&options, "--root without --onto");
1178
1179         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1180                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1181
1182         switch (options.type) {
1183         case REBASE_MERGE:
1184         case REBASE_INTERACTIVE:
1185         case REBASE_PRESERVE_MERGES:
1186                 options.state_dir = merge_dir();
1187                 break;
1188         case REBASE_AM:
1189                 options.state_dir = apply_dir();
1190                 break;
1191         default:
1192                 /* the default rebase backend is `--am` */
1193                 options.type = REBASE_AM;
1194                 options.state_dir = apply_dir();
1195                 break;
1196         }
1197
1198         if (options.git_am_opt.len) {
1199                 const char *p;
1200
1201                 /* all am options except -q are compatible only with --am */
1202                 strbuf_reset(&buf);
1203                 strbuf_addbuf(&buf, &options.git_am_opt);
1204                 strbuf_addch(&buf, ' ');
1205                 while ((p = strstr(buf.buf, " -q ")))
1206                         strbuf_splice(&buf, p - buf.buf, 4, " ", 1);
1207                 strbuf_trim(&buf);
1208
1209                 if (is_interactive(&options) && buf.len)
1210                         die(_("error: cannot combine interactive options "
1211                               "(--interactive, --exec, --rebase-merges, "
1212                               "--preserve-merges, --keep-empty, --root + "
1213                               "--onto) with am options (%s)"), buf.buf);
1214                 if (options.type == REBASE_MERGE && buf.len)
1215                         die(_("error: cannot combine merge options (--merge, "
1216                               "--strategy, --strategy-option) with am options "
1217                               "(%s)"), buf.buf);
1218         }
1219
1220         if (options.signoff) {
1221                 if (options.type == REBASE_PRESERVE_MERGES)
1222                         die("cannot combine '--signoff' with "
1223                             "'--preserve-merges'");
1224                 strbuf_addstr(&options.git_am_opt, " --signoff");
1225                 options.flags |= REBASE_FORCE;
1226         }
1227
1228         if (options.type == REBASE_PRESERVE_MERGES)
1229                 /*
1230                  * Note: incompatibility with --signoff handled in signoff block above
1231                  * Note: incompatibility with --interactive is just a strong warning;
1232                  *       git-rebase.txt caveats with "unless you know what you are doing"
1233                  */
1234                 if (options.rebase_merges)
1235                         die(_("error: cannot combine '--preserve-merges' with "
1236                               "'--rebase-merges'"));
1237
1238         if (options.rebase_merges) {
1239                 if (strategy_options.nr)
1240                         die(_("error: cannot combine '--rebase-merges' with "
1241                               "'--strategy-option'"));
1242                 if (options.strategy)
1243                         die(_("error: cannot combine '--rebase-merges' with "
1244                               "'--strategy'"));
1245         }
1246
1247         if (!options.root) {
1248                 if (argc < 1) {
1249                         struct branch *branch;
1250
1251                         branch = branch_get(NULL);
1252                         options.upstream_name = branch_get_upstream(branch,
1253                                                                     NULL);
1254                         if (!options.upstream_name)
1255                                 error_on_missing_default_upstream();
1256                         if (fork_point < 0)
1257                                 fork_point = 1;
1258                 } else {
1259                         options.upstream_name = argv[0];
1260                         argc--;
1261                         argv++;
1262                         if (!strcmp(options.upstream_name, "-"))
1263                                 options.upstream_name = "@{-1}";
1264                 }
1265                 options.upstream = peel_committish(options.upstream_name);
1266                 if (!options.upstream)
1267                         die(_("invalid upstream '%s'"), options.upstream_name);
1268                 options.upstream_arg = options.upstream_name;
1269         } else {
1270                 if (!options.onto_name) {
1271                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1272                                         &squash_onto, NULL, NULL) < 0)
1273                                 die(_("Could not create new root commit"));
1274                         options.squash_onto = &squash_onto;
1275                         options.onto_name = squash_onto_name =
1276                                 xstrdup(oid_to_hex(&squash_onto));
1277                 }
1278                 options.upstream_name = NULL;
1279                 options.upstream = NULL;
1280                 if (argc > 1)
1281                         usage_with_options(builtin_rebase_usage,
1282                                            builtin_rebase_options);
1283                 options.upstream_arg = "--root";
1284         }
1285
1286         /* Make sure the branch to rebase onto is valid. */
1287         if (!options.onto_name)
1288                 options.onto_name = options.upstream_name;
1289         if (strstr(options.onto_name, "...")) {
1290                 if (get_oid_mb(options.onto_name, &merge_base) < 0)
1291                         die(_("'%s': need exactly one merge base"),
1292                             options.onto_name);
1293                 options.onto = lookup_commit_or_die(&merge_base,
1294                                                     options.onto_name);
1295         } else {
1296                 options.onto = peel_committish(options.onto_name);
1297                 if (!options.onto)
1298                         die(_("Does not point to a valid commit '%s'"),
1299                                 options.onto_name);
1300         }
1301
1302         /*
1303          * If the branch to rebase is given, that is the branch we will rebase
1304          * branch_name -- branch/commit being rebased, or
1305          *                HEAD (already detached)
1306          * orig_head -- commit object name of tip of the branch before rebasing
1307          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1308          */
1309         if (argc == 1) {
1310                 /* Is it "rebase other branchname" or "rebase other commit"? */
1311                 branch_name = argv[0];
1312                 options.switch_to = argv[0];
1313
1314                 /* Is it a local branch? */
1315                 strbuf_reset(&buf);
1316                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1317                 if (!read_ref(buf.buf, &options.orig_head))
1318                         options.head_name = xstrdup(buf.buf);
1319                 /* If not is it a valid ref (branch or commit)? */
1320                 else if (!get_oid(branch_name, &options.orig_head))
1321                         options.head_name = NULL;
1322                 else
1323                         die(_("fatal: no such branch/commit '%s'"),
1324                             branch_name);
1325         } else if (argc == 0) {
1326                 /* Do not need to switch branches, we are already on it. */
1327                 options.head_name =
1328                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1329                                          &flags));
1330                 if (!options.head_name)
1331                         die(_("No such ref: %s"), "HEAD");
1332                 if (flags & REF_ISSYMREF) {
1333                         if (!skip_prefix(options.head_name,
1334                                          "refs/heads/", &branch_name))
1335                                 branch_name = options.head_name;
1336
1337                 } else {
1338                         free(options.head_name);
1339                         options.head_name = NULL;
1340                         branch_name = "HEAD";
1341                 }
1342                 if (get_oid("HEAD", &options.orig_head))
1343                         die(_("Could not resolve HEAD to a revision"));
1344         } else
1345                 BUG("unexpected number of arguments left to parse");
1346
1347         if (fork_point > 0) {
1348                 struct commit *head =
1349                         lookup_commit_reference(the_repository,
1350                                                 &options.orig_head);
1351                 options.restrict_revision =
1352                         get_fork_point(options.upstream_name, head);
1353         }
1354
1355         if (read_index(the_repository->index) < 0)
1356                 die(_("could not read index"));
1357
1358         if (options.autostash) {
1359                 struct lock_file lock_file = LOCK_INIT;
1360                 int fd;
1361
1362                 fd = hold_locked_index(&lock_file, 0);
1363                 refresh_cache(REFRESH_QUIET);
1364                 if (0 <= fd)
1365                         update_index_if_able(&the_index, &lock_file);
1366                 rollback_lock_file(&lock_file);
1367
1368                 if (has_unstaged_changes(1) || has_uncommitted_changes(1)) {
1369                         const char *autostash =
1370                                 state_dir_path("autostash", &options);
1371                         struct child_process stash = CHILD_PROCESS_INIT;
1372                         struct object_id oid;
1373                         struct commit *head =
1374                                 lookup_commit_reference(the_repository,
1375                                                         &options.orig_head);
1376
1377                         argv_array_pushl(&stash.args,
1378                                          "stash", "create", "autostash", NULL);
1379                         stash.git_cmd = 1;
1380                         stash.no_stdin = 1;
1381                         strbuf_reset(&buf);
1382                         if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
1383                                 die(_("Cannot autostash"));
1384                         strbuf_trim_trailing_newline(&buf);
1385                         if (get_oid(buf.buf, &oid))
1386                                 die(_("Unexpected stash response: '%s'"),
1387                                     buf.buf);
1388                         strbuf_reset(&buf);
1389                         strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
1390
1391                         if (safe_create_leading_directories_const(autostash))
1392                                 die(_("Could not create directory for '%s'"),
1393                                     options.state_dir);
1394                         write_file(autostash, "%s", oid_to_hex(&oid));
1395                         printf(_("Created autostash: %s\n"), buf.buf);
1396                         if (reset_head(&head->object.oid, "reset --hard",
1397                                        NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
1398                                 die(_("could not reset --hard"));
1399                         printf(_("HEAD is now at %s"),
1400                                find_unique_abbrev(&head->object.oid,
1401                                                   DEFAULT_ABBREV));
1402                         strbuf_reset(&buf);
1403                         pp_commit_easy(CMIT_FMT_ONELINE, head, &buf);
1404                         if (buf.len > 0)
1405                                 printf(" %s", buf.buf);
1406                         putchar('\n');
1407
1408                         if (discard_index(the_repository->index) < 0 ||
1409                                 read_index(the_repository->index) < 0)
1410                                 die(_("could not read index"));
1411                 }
1412         }
1413
1414         if (require_clean_work_tree("rebase",
1415                                     _("Please commit or stash them."), 1, 1)) {
1416                 ret = 1;
1417                 goto cleanup;
1418         }
1419
1420         /*
1421          * Now we are rebasing commits upstream..orig_head (or with --root,
1422          * everything leading up to orig_head) on top of onto.
1423          */
1424
1425         /*
1426          * Check if we are already based on onto with linear history,
1427          * but this should be done only when upstream and onto are the same
1428          * and if this is not an interactive rebase.
1429          */
1430         if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
1431             !is_interactive(&options) && !options.restrict_revision &&
1432             options.upstream &&
1433             !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
1434                 int flag;
1435
1436                 if (!(options.flags & REBASE_FORCE)) {
1437                         /* Lazily switch to the target branch if needed... */
1438                         if (options.switch_to) {
1439                                 struct object_id oid;
1440
1441                                 if (get_oid(options.switch_to, &oid) < 0) {
1442                                         ret = !!error(_("could not parse '%s'"),
1443                                                       options.switch_to);
1444                                         goto cleanup;
1445                                 }
1446
1447                                 strbuf_reset(&buf);
1448                                 strbuf_addf(&buf, "rebase: checkout %s",
1449                                             options.switch_to);
1450                                 if (reset_head(&oid, "checkout",
1451                                                options.head_name, 0,
1452                                                NULL, NULL) < 0) {
1453                                         ret = !!error(_("could not switch to "
1454                                                         "%s"),
1455                                                       options.switch_to);
1456                                         goto cleanup;
1457                                 }
1458                         }
1459
1460                         if (!(options.flags & REBASE_NO_QUIET))
1461                                 ; /* be quiet */
1462                         else if (!strcmp(branch_name, "HEAD") &&
1463                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1464                                 puts(_("HEAD is up to date."));
1465                         else
1466                                 printf(_("Current branch %s is up to date.\n"),
1467                                        branch_name);
1468                         ret = !!finish_rebase(&options);
1469                         goto cleanup;
1470                 } else if (!(options.flags & REBASE_NO_QUIET))
1471                         ; /* be quiet */
1472                 else if (!strcmp(branch_name, "HEAD") &&
1473                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1474                         puts(_("HEAD is up to date, rebase forced."));
1475                 else
1476                         printf(_("Current branch %s is up to date, rebase "
1477                                  "forced.\n"), branch_name);
1478         }
1479
1480         /* If a hook exists, give it a chance to interrupt*/
1481         if (!ok_to_skip_pre_rebase &&
1482             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
1483                         argc ? argv[0] : NULL, NULL))
1484                 die(_("The pre-rebase hook refused to rebase."));
1485
1486         if (options.flags & REBASE_DIFFSTAT) {
1487                 struct diff_options opts;
1488
1489                 if (options.flags & REBASE_VERBOSE)
1490                         printf(_("Changes from %s to %s:\n"),
1491                                 oid_to_hex(&merge_base),
1492                                 oid_to_hex(&options.onto->object.oid));
1493
1494                 /* We want color (if set), but no pager */
1495                 diff_setup(&opts);
1496                 opts.stat_width = -1; /* use full terminal width */
1497                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
1498                 opts.output_format |=
1499                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
1500                 opts.detect_rename = DIFF_DETECT_RENAME;
1501                 diff_setup_done(&opts);
1502                 diff_tree_oid(&merge_base, &options.onto->object.oid,
1503                               "", &opts);
1504                 diffcore_std(&opts);
1505                 diff_flush(&opts);
1506         }
1507
1508         if (is_interactive(&options))
1509                 goto run_rebase;
1510
1511         /* Detach HEAD and reset the tree */
1512         if (options.flags & REBASE_NO_QUIET)
1513                 printf(_("First, rewinding head to replay your work on top of "
1514                          "it...\n"));
1515
1516         strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
1517         if (reset_head(&options.onto->object.oid, "checkout", NULL,
1518                        RESET_HEAD_DETACH, NULL, msg.buf))
1519                 die(_("Could not detach HEAD"));
1520         strbuf_release(&msg);
1521
1522         /*
1523          * If the onto is a proper descendant of the tip of the branch, then
1524          * we just fast-forwarded.
1525          */
1526         strbuf_reset(&msg);
1527         if (!oidcmp(&merge_base, &options.orig_head)) {
1528                 printf(_("Fast-forwarded %s to %s. \n"),
1529                         branch_name, options.onto_name);
1530                 strbuf_addf(&msg, "rebase finished: %s onto %s",
1531                         options.head_name ? options.head_name : "detached HEAD",
1532                         oid_to_hex(&options.onto->object.oid));
1533                 reset_head(NULL, "Fast-forwarded", options.head_name, 0,
1534                            "HEAD", msg.buf);
1535                 strbuf_release(&msg);
1536                 ret = !!finish_rebase(&options);
1537                 goto cleanup;
1538         }
1539
1540         strbuf_addf(&revisions, "%s..%s",
1541                     options.root ? oid_to_hex(&options.onto->object.oid) :
1542                     (options.restrict_revision ?
1543                      oid_to_hex(&options.restrict_revision->object.oid) :
1544                      oid_to_hex(&options.upstream->object.oid)),
1545                     oid_to_hex(&options.orig_head));
1546
1547         options.revisions = revisions.buf;
1548
1549 run_rebase:
1550         ret = !!run_specific_rebase(&options);
1551
1552 cleanup:
1553         strbuf_release(&revisions);
1554         free(options.head_name);
1555         free(options.gpg_sign_opt);
1556         free(options.cmd);
1557         free(squash_onto_name);
1558         return ret;
1559 }