git.oblomov.eu Git - git/blob - builtin/rebase.c

   1 /*
   2  * "git rebase" builtin command
   3  *
   4  * Copyright (c) 2018 Pratik Karki
   5  */
   6
   7 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   8 #include "builtin.h"
   9 #include "run-command.h"
  10 #include "exec-cmd.h"
  11 #include "strvec.h"
  12 #include "dir.h"
  13 #include "packfile.h"
  14 #include "refs.h"
  15 #include "quote.h"
  16 #include "config.h"
  17 #include "cache-tree.h"
  18 #include "unpack-trees.h"
  19 #include "lockfile.h"
  20 #include "parse-options.h"
  21 #include "commit.h"
  22 #include "diff.h"
  23 #include "wt-status.h"
  24 #include "revision.h"
  25 #include "commit-reach.h"
  26 #include "rerere.h"
  27 #include "branch.h"
  28 #include "sequencer.h"
  29 #include "rebase-interactive.h"
  30 #include "reset.h"
  31
  32 #define DEFAULT_REFLOG_ACTION "rebase"
  33
  34 static char const * const builtin_rebase_usage[] = {
  35         N_("git rebase [-i] [options] [--exec <cmd>] "
  36                 "[--onto <newbase> | --keep-base] [<upstream> [<branch>]]"),
  37         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  38                 "--root [<branch>]"),
  39         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  40         NULL
  41 };
  42
  43 static GIT_PATH_FUNC(path_squash_onto, "rebase-merge/squash-onto")
  44 static GIT_PATH_FUNC(path_interactive, "rebase-merge/interactive")
  45 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  46 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  47
  48 enum rebase_type {
  49         REBASE_UNSPECIFIED = -1,
  50         REBASE_APPLY,
  51         REBASE_MERGE,
  52         REBASE_PRESERVE_MERGES
  53 };
  54
  55 enum empty_type {
  56         EMPTY_UNSPECIFIED = -1,
  57         EMPTY_DROP,
  58         EMPTY_KEEP,
  59         EMPTY_ASK
  60 };
  61
  62 struct rebase_options {
  63         enum rebase_type type;
  64         enum empty_type empty;
  65         const char *default_backend;
  66         const char *state_dir;
  67         struct commit *upstream;
  68         const char *upstream_name;
  69         const char *upstream_arg;
  70         char *head_name;
  71         struct object_id orig_head;
  72         struct commit *onto;
  73         const char *onto_name;
  74         const char *revisions;
  75         const char *switch_to;
  76         int root, root_with_onto;
  77         struct object_id *squash_onto;
  78         struct commit *restrict_revision;
  79         int dont_finish_rebase;
  80         enum {
  81                 REBASE_NO_QUIET = 1<<0,
  82                 REBASE_VERBOSE = 1<<1,
  83                 REBASE_DIFFSTAT = 1<<2,
  84                 REBASE_FORCE = 1<<3,
  85                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  86         } flags;
  87         struct strvec git_am_opts;
  88         const char *action;
  89         int signoff;
  90         int allow_rerere_autoupdate;
  91         int keep_empty;
  92         int autosquash;
  93         char *gpg_sign_opt;
  94         int autostash;
  95         int committer_date_is_author_date;
  96         int ignore_date;
  97         char *cmd;
  98         int allow_empty_message;
  99         int rebase_merges, rebase_cousins;
 100         char *strategy, *strategy_opts;
 101         struct strbuf git_format_patch_opt;
 102         int reschedule_failed_exec;
 103         int use_legacy_rebase;
 104         int reapply_cherry_picks;
 105 };
 106
 107 #define REBASE_OPTIONS_INIT {                           \
 108                 .type = REBASE_UNSPECIFIED,             \
 109                 .empty = EMPTY_UNSPECIFIED,             \
 110                 .keep_empty = 1,                        \
 111                 .default_backend = "merge",             \
 112                 .flags = REBASE_NO_QUIET,               \
 113                 .git_am_opts = STRVEC_INIT,             \
 114                 .git_format_patch_opt = STRBUF_INIT     \
 115         }
 116
 117 static struct replay_opts get_replay_opts(const struct rebase_options *opts)
 118 {
 119         struct replay_opts replay = REPLAY_OPTS_INIT;
 120
 121         replay.action = REPLAY_INTERACTIVE_REBASE;
 122         sequencer_init_config(&replay);
 123
 124         replay.signoff = opts->signoff;
 125         replay.allow_ff = !(opts->flags & REBASE_FORCE);
 126         if (opts->allow_rerere_autoupdate)
 127                 replay.allow_rerere_auto = opts->allow_rerere_autoupdate;
 128         replay.allow_empty = 1;
 129         replay.allow_empty_message = opts->allow_empty_message;
 130         replay.drop_redundant_commits = (opts->empty == EMPTY_DROP);
 131         replay.keep_redundant_commits = (opts->empty == EMPTY_KEEP);
 132         replay.quiet = !(opts->flags & REBASE_NO_QUIET);
 133         replay.verbose = opts->flags & REBASE_VERBOSE;
 134         replay.reschedule_failed_exec = opts->reschedule_failed_exec;
 135         replay.committer_date_is_author_date =
 136                                         opts->committer_date_is_author_date;
 137         replay.ignore_date = opts->ignore_date;
 138         replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
 139         replay.strategy = opts->strategy;
 140
 141         if (opts->strategy_opts)
 142                 parse_strategy_opts(&replay, opts->strategy_opts);
 143
 144         if (opts->squash_onto) {
 145                 oidcpy(&replay.squash_onto, opts->squash_onto);
 146                 replay.have_squash_onto = 1;
 147         }
 148
 149         return replay;
 150 }
 151
 152 enum action {
 153         ACTION_NONE = 0,
 154         ACTION_CONTINUE,
 155         ACTION_SKIP,
 156         ACTION_ABORT,
 157         ACTION_QUIT,
 158         ACTION_EDIT_TODO,
 159         ACTION_SHOW_CURRENT_PATCH,
 160         ACTION_SHORTEN_OIDS,
 161         ACTION_EXPAND_OIDS,
 162         ACTION_CHECK_TODO_LIST,
 163         ACTION_REARRANGE_SQUASH,
 164         ACTION_ADD_EXEC
 165 };
 166
 167 static const char *action_names[] = { "undefined",
 168                                       "continue",
 169                                       "skip",
 170                                       "abort",
 171                                       "quit",
 172                                       "edit_todo",
 173                                       "show_current_patch" };
 174
 175 static int add_exec_commands(struct string_list *commands)
 176 {
 177         const char *todo_file = rebase_path_todo();
 178         struct todo_list todo_list = TODO_LIST_INIT;
 179         int res;
 180
 181         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 182                 return error_errno(_("could not read '%s'."), todo_file);
 183
 184         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 185                                         &todo_list)) {
 186                 todo_list_release(&todo_list);
 187                 return error(_("unusable todo list: '%s'"), todo_file);
 188         }
 189
 190         todo_list_add_exec_commands(&todo_list, commands);
 191         res = todo_list_write_to_file(the_repository, &todo_list,
 192                                       todo_file, NULL, NULL, -1, 0);
 193         todo_list_release(&todo_list);
 194
 195         if (res)
 196                 return error_errno(_("could not write '%s'."), todo_file);
 197         return 0;
 198 }
 199
 200 static int rearrange_squash_in_todo_file(void)
 201 {
 202         const char *todo_file = rebase_path_todo();
 203         struct todo_list todo_list = TODO_LIST_INIT;
 204         int res = 0;
 205
 206         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 207                 return error_errno(_("could not read '%s'."), todo_file);
 208         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 209                                         &todo_list)) {
 210                 todo_list_release(&todo_list);
 211                 return error(_("unusable todo list: '%s'"), todo_file);
 212         }
 213
 214         res = todo_list_rearrange_squash(&todo_list);
 215         if (!res)
 216                 res = todo_list_write_to_file(the_repository, &todo_list,
 217                                               todo_file, NULL, NULL, -1, 0);
 218
 219         todo_list_release(&todo_list);
 220
 221         if (res)
 222                 return error_errno(_("could not write '%s'."), todo_file);
 223         return 0;
 224 }
 225
 226 static int transform_todo_file(unsigned flags)
 227 {
 228         const char *todo_file = rebase_path_todo();
 229         struct todo_list todo_list = TODO_LIST_INIT;
 230         int res;
 231
 232         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 233                 return error_errno(_("could not read '%s'."), todo_file);
 234
 235         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 236                                         &todo_list)) {
 237                 todo_list_release(&todo_list);
 238                 return error(_("unusable todo list: '%s'"), todo_file);
 239         }
 240
 241         res = todo_list_write_to_file(the_repository, &todo_list, todo_file,
 242                                       NULL, NULL, -1, flags);
 243         todo_list_release(&todo_list);
 244
 245         if (res)
 246                 return error_errno(_("could not write '%s'."), todo_file);
 247         return 0;
 248 }
 249
 250 static int edit_todo_file(unsigned flags)
 251 {
 252         const char *todo_file = rebase_path_todo();
 253         struct todo_list todo_list = TODO_LIST_INIT,
 254                 new_todo = TODO_LIST_INIT;
 255         int res = 0;
 256
 257         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 258                 return error_errno(_("could not read '%s'."), todo_file);
 259
 260         strbuf_stripspace(&todo_list.buf, 1);
 261         res = edit_todo_list(the_repository, &todo_list, &new_todo, NULL, NULL, flags);
 262         if (!res && todo_list_write_to_file(the_repository, &new_todo, todo_file,
 263                                             NULL, NULL, -1, flags & ~(TODO_LIST_SHORTEN_IDS)))
 264                 res = error_errno(_("could not write '%s'"), todo_file);
 265
 266         todo_list_release(&todo_list);
 267         todo_list_release(&new_todo);
 268
 269         return res;
 270 }
 271
 272 static int get_revision_ranges(struct commit *upstream, struct commit *onto,
 273                                struct object_id *orig_head, const char **head_hash,
 274                                char **revisions, char **shortrevisions)
 275 {
 276         struct commit *base_rev = upstream ? upstream : onto;
 277         const char *shorthead;
 278
 279         *head_hash = find_unique_abbrev(orig_head, GIT_MAX_HEXSZ);
 280         *revisions = xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oid),
 281                                                    *head_hash);
 282
 283         shorthead = find_unique_abbrev(orig_head, DEFAULT_ABBREV);
 284
 285         if (upstream) {
 286                 const char *shortrev;
 287
 288                 shortrev = find_unique_abbrev(&base_rev->object.oid,
 289                                               DEFAULT_ABBREV);
 290
 291                 *shortrevisions = xstrfmt("%s..%s", shortrev, shorthead);
 292         } else
 293                 *shortrevisions = xstrdup(shorthead);
 294
 295         return 0;
 296 }
 297
 298 static int init_basic_state(struct replay_opts *opts, const char *head_name,
 299                             struct commit *onto, const char *orig_head)
 300 {
 301         FILE *interactive;
 302
 303         if (!is_directory(merge_dir()) && mkdir_in_gitdir(merge_dir()))
 304                 return error_errno(_("could not create temporary %s"), merge_dir());
 305
 306         delete_reflog("REBASE_HEAD");
 307
 308         interactive = fopen(path_interactive(), "w");
 309         if (!interactive)
 310                 return error_errno(_("could not mark as interactive"));
 311         fclose(interactive);
 312
 313         return write_basic_state(opts, head_name, onto, orig_head);
 314 }
 315
 316 static void split_exec_commands(const char *cmd, struct string_list *commands)
 317 {
 318         if (cmd && *cmd) {
 319                 string_list_split(commands, cmd, '\n', -1);
 320
 321                 /* rebase.c adds a new line to cmd after every command,
 322                  * so here the last command is always empty */
 323                 string_list_remove_empty_items(commands, 0);
 324         }
 325 }
 326
 327 static int do_interactive_rebase(struct rebase_options *opts, unsigned flags)
 328 {
 329         int ret;
 330         const char *head_hash = NULL;
 331         char *revisions = NULL, *shortrevisions = NULL;
 332         struct strvec make_script_args = STRVEC_INIT;
 333         struct todo_list todo_list = TODO_LIST_INIT;
 334         struct replay_opts replay = get_replay_opts(opts);
 335         struct string_list commands = STRING_LIST_INIT_DUP;
 336
 337         if (get_revision_ranges(opts->upstream, opts->onto, &opts->orig_head,
 338                                 &head_hash, &revisions, &shortrevisions))
 339                 return -1;
 340
 341         if (init_basic_state(&replay,
 342                              opts->head_name ? opts->head_name : "detached HEAD",
 343                              opts->onto, head_hash)) {
 344                 free(revisions);
 345                 free(shortrevisions);
 346
 347                 return -1;
 348         }
 349
 350         if (!opts->upstream && opts->squash_onto)
 351                 write_file(path_squash_onto(), "%s\n",
 352                            oid_to_hex(opts->squash_onto));
 353
 354         strvec_pushl(&make_script_args, "", revisions, NULL);
 355         if (opts->restrict_revision)
 356                 strvec_pushf(&make_script_args, "^%s",
 357                              oid_to_hex(&opts->restrict_revision->object.oid));
 358
 359         ret = sequencer_make_script(the_repository, &todo_list.buf,
 360                                     make_script_args.nr, make_script_args.v,
 361                                     flags);
 362
 363         if (ret)
 364                 error(_("could not generate todo list"));
 365         else {
 366                 discard_cache();
 367                 if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 368                                                 &todo_list))
 369                         BUG("unusable todo list");
 370
 371                 split_exec_commands(opts->cmd, &commands);
 372                 ret = complete_action(the_repository, &replay, flags,
 373                         shortrevisions, opts->onto_name, opts->onto, head_hash,
 374                         &commands, opts->autosquash, &todo_list);
 375         }
 376
 377         string_list_clear(&commands, 0);
 378         free(revisions);
 379         free(shortrevisions);
 380         todo_list_release(&todo_list);
 381         strvec_clear(&make_script_args);
 382
 383         return ret;
 384 }
 385
 386 static int run_sequencer_rebase(struct rebase_options *opts,
 387                                   enum action command)
 388 {
 389         unsigned flags = 0;
 390         int abbreviate_commands = 0, ret = 0;
 391
 392         git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
 393
 394         flags |= opts->keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
 395         flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
 396         flags |= opts->rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
 397         flags |= opts->rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
 398         flags |= opts->root_with_onto ? TODO_LIST_ROOT_WITH_ONTO : 0;
 399         flags |= command == ACTION_SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
 400         flags |= opts->reapply_cherry_picks ? TODO_LIST_REAPPLY_CHERRY_PICKS : 0;
 401
 402         switch (command) {
 403         case ACTION_NONE: {
 404                 if (!opts->onto && !opts->upstream)
 405                         die(_("a base commit must be provided with --upstream or --onto"));
 406
 407                 ret = do_interactive_rebase(opts, flags);
 408                 break;
 409         }
 410         case ACTION_SKIP: {
 411                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
 412
 413                 rerere_clear(the_repository, &merge_rr);
 414         }
 415                 /* fallthrough */
 416         case ACTION_CONTINUE: {
 417                 struct replay_opts replay_opts = get_replay_opts(opts);
 418
 419                 ret = sequencer_continue(the_repository, &replay_opts);
 420                 break;
 421         }
 422         case ACTION_EDIT_TODO:
 423                 ret = edit_todo_file(flags);
 424                 break;
 425         case ACTION_SHOW_CURRENT_PATCH: {
 426                 struct child_process cmd = CHILD_PROCESS_INIT;
 427
 428                 cmd.git_cmd = 1;
 429                 strvec_pushl(&cmd.args, "show", "REBASE_HEAD", "--", NULL);
 430                 ret = run_command(&cmd);
 431
 432                 break;
 433         }
 434         case ACTION_SHORTEN_OIDS:
 435         case ACTION_EXPAND_OIDS:
 436                 ret = transform_todo_file(flags);
 437                 break;
 438         case ACTION_CHECK_TODO_LIST:
 439                 ret = check_todo_list_from_file(the_repository);
 440                 break;
 441         case ACTION_REARRANGE_SQUASH:
 442                 ret = rearrange_squash_in_todo_file();
 443                 break;
 444         case ACTION_ADD_EXEC: {
 445                 struct string_list commands = STRING_LIST_INIT_DUP;
 446
 447                 split_exec_commands(opts->cmd, &commands);
 448                 ret = add_exec_commands(&commands);
 449                 string_list_clear(&commands, 0);
 450                 break;
 451         }
 452         default:
 453                 BUG("invalid command '%d'", command);
 454         }
 455
 456         return ret;
 457 }
 458
 459 static void imply_merge(struct rebase_options *opts, const char *option);
 460 static int parse_opt_keep_empty(const struct option *opt, const char *arg,
 461                                 int unset)
 462 {
 463         struct rebase_options *opts = opt->value;
 464
 465         BUG_ON_OPT_ARG(arg);
 466
 467         imply_merge(opts, unset ? "--no-keep-empty" : "--keep-empty");
 468         opts->keep_empty = !unset;
 469         opts->type = REBASE_MERGE;
 470         return 0;
 471 }
 472
 473 static const char * const builtin_rebase_interactive_usage[] = {
 474         N_("git rebase--interactive [<options>]"),
 475         NULL
 476 };
 477
 478 int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 479 {
 480         struct rebase_options opts = REBASE_OPTIONS_INIT;
 481         struct object_id squash_onto = null_oid;
 482         enum action command = ACTION_NONE;
 483         struct option options[] = {
 484                 OPT_NEGBIT(0, "ff", &opts.flags, N_("allow fast-forward"),
 485                            REBASE_FORCE),
 486                 OPT_CALLBACK_F('k', "keep-empty", &options, NULL,
 487                         N_("keep commits which start empty"),
 488                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
 489                         parse_opt_keep_empty),
 490                 OPT_BOOL_F(0, "allow-empty-message", &opts.allow_empty_message,
 491                            N_("allow commits with empty messages"),
 492                            PARSE_OPT_HIDDEN),
 493                 OPT_BOOL(0, "rebase-merges", &opts.rebase_merges, N_("rebase merge commits")),
 494                 OPT_BOOL(0, "rebase-cousins", &opts.rebase_cousins,
 495                          N_("keep original branch points of cousins")),
 496                 OPT_BOOL(0, "autosquash", &opts.autosquash,
 497                          N_("move commits that begin with squash!/fixup!")),
 498                 OPT_BOOL(0, "signoff", &opts.signoff, N_("sign commits")),
 499                 OPT_BIT('v', "verbose", &opts.flags,
 500                         N_("display a diffstat of what changed upstream"),
 501                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 502                 OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
 503                             ACTION_CONTINUE),
 504                 OPT_CMDMODE(0, "skip", &command, N_("skip commit"), ACTION_SKIP),
 505                 OPT_CMDMODE(0, "edit-todo", &command, N_("edit the todo list"),
 506                             ACTION_EDIT_TODO),
 507                 OPT_CMDMODE(0, "show-current-patch", &command, N_("show the current patch"),
 508                             ACTION_SHOW_CURRENT_PATCH),
 509                 OPT_CMDMODE(0, "shorten-ids", &command,
 510                         N_("shorten commit ids in the todo list"), ACTION_SHORTEN_OIDS),
 511                 OPT_CMDMODE(0, "expand-ids", &command,
 512                         N_("expand commit ids in the todo list"), ACTION_EXPAND_OIDS),
 513                 OPT_CMDMODE(0, "check-todo-list", &command,
 514                         N_("check the todo list"), ACTION_CHECK_TODO_LIST),
 515                 OPT_CMDMODE(0, "rearrange-squash", &command,
 516                         N_("rearrange fixup/squash lines"), ACTION_REARRANGE_SQUASH),
 517                 OPT_CMDMODE(0, "add-exec-commands", &command,
 518                         N_("insert exec commands in todo list"), ACTION_ADD_EXEC),
 519                 { OPTION_CALLBACK, 0, "onto", &opts.onto, N_("onto"), N_("onto"),
 520                   PARSE_OPT_NONEG, parse_opt_commit, 0 },
 521                 { OPTION_CALLBACK, 0, "restrict-revision", &opts.restrict_revision,
 522                   N_("restrict-revision"), N_("restrict revision"),
 523                   PARSE_OPT_NONEG, parse_opt_commit, 0 },
 524                 { OPTION_CALLBACK, 0, "squash-onto", &squash_onto, N_("squash-onto"),
 525                   N_("squash onto"), PARSE_OPT_NONEG, parse_opt_object_id, 0 },
 526                 { OPTION_CALLBACK, 0, "upstream", &opts.upstream, N_("upstream"),
 527                   N_("the upstream commit"), PARSE_OPT_NONEG, parse_opt_commit,
 528                   0 },
 529                 OPT_STRING(0, "head-name", &opts.head_name, N_("head-name"), N_("head name")),
 530                 { OPTION_STRING, 'S', "gpg-sign", &opts.gpg_sign_opt, N_("key-id"),
 531                         N_("GPG-sign commits"),
 532                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 533                 OPT_STRING(0, "strategy", &opts.strategy, N_("strategy"),
 534                            N_("rebase strategy")),
 535                 OPT_STRING(0, "strategy-opts", &opts.strategy_opts, N_("strategy-opts"),
 536                            N_("strategy options")),
 537                 OPT_STRING(0, "switch-to", &opts.switch_to, N_("switch-to"),
 538                            N_("the branch or commit to checkout")),
 539                 OPT_STRING(0, "onto-name", &opts.onto_name, N_("onto-name"), N_("onto name")),
 540                 OPT_STRING(0, "cmd", &opts.cmd, N_("cmd"), N_("the command to run")),
 541                 OPT_RERERE_AUTOUPDATE(&opts.allow_rerere_autoupdate),
 542                 OPT_BOOL(0, "reschedule-failed-exec", &opts.reschedule_failed_exec,
 543                          N_("automatically re-schedule any `exec` that fails")),
 544                 OPT_END()
 545         };
 546
 547         opts.rebase_cousins = -1;
 548
 549         if (argc == 1)
 550                 usage_with_options(builtin_rebase_interactive_usage, options);
 551
 552         argc = parse_options(argc, argv, prefix, options,
 553                         builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
 554
 555         if (!is_null_oid(&squash_onto))
 556                 opts.squash_onto = &squash_onto;
 557
 558         if (opts.rebase_cousins >= 0 && !opts.rebase_merges)
 559                 warning(_("--[no-]rebase-cousins has no effect without "
 560                           "--rebase-merges"));
 561
 562         return !!run_sequencer_rebase(&opts, command);
 563 }
 564
 565 static int is_merge(struct rebase_options *opts)
 566 {
 567         return opts->type == REBASE_MERGE ||
 568                 opts->type == REBASE_PRESERVE_MERGES;
 569 }
 570
 571 static void imply_merge(struct rebase_options *opts, const char *option)
 572 {
 573         switch (opts->type) {
 574         case REBASE_APPLY:
 575                 die(_("%s requires the merge backend"), option);
 576                 break;
 577         case REBASE_MERGE:
 578         case REBASE_PRESERVE_MERGES:
 579                 break;
 580         default:
 581                 opts->type = REBASE_MERGE; /* implied */
 582                 break;
 583         }
 584 }
 585
 586 /* Returns the filename prefixed by the state_dir */
 587 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 588 {
 589         static struct strbuf path = STRBUF_INIT;
 590         static size_t prefix_len;
 591
 592         if (!prefix_len) {
 593                 strbuf_addf(&path, "%s/", opts->state_dir);
 594                 prefix_len = path.len;
 595         }
 596
 597         strbuf_setlen(&path, prefix_len);
 598         strbuf_addstr(&path, filename);
 599         return path.buf;
 600 }
 601
 602 /* Initialize the rebase options from the state directory. */
 603 static int read_basic_state(struct rebase_options *opts)
 604 {
 605         struct strbuf head_name = STRBUF_INIT;
 606         struct strbuf buf = STRBUF_INIT;
 607         struct object_id oid;
 608
 609         if (!read_oneliner(&head_name, state_dir_path("head-name", opts),
 610                            READ_ONELINER_WARN_MISSING) ||
 611             !read_oneliner(&buf, state_dir_path("onto", opts),
 612                            READ_ONELINER_WARN_MISSING))
 613                 return -1;
 614         opts->head_name = starts_with(head_name.buf, "refs/") ?
 615                 xstrdup(head_name.buf) : NULL;
 616         strbuf_release(&head_name);
 617         if (get_oid(buf.buf, &oid))
 618                 return error(_("could not get 'onto': '%s'"), buf.buf);
 619         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 620
 621         /*
 622          * We always write to orig-head, but interactive rebase used to write to
 623          * head. Fall back to reading from head to cover for the case that the
 624          * user upgraded git with an ongoing interactive rebase.
 625          */
 626         strbuf_reset(&buf);
 627         if (file_exists(state_dir_path("orig-head", opts))) {
 628                 if (!read_oneliner(&buf, state_dir_path("orig-head", opts),
 629                                    READ_ONELINER_WARN_MISSING))
 630                         return -1;
 631         } else if (!read_oneliner(&buf, state_dir_path("head", opts),
 632                                   READ_ONELINER_WARN_MISSING))
 633                 return -1;
 634         if (get_oid(buf.buf, &opts->orig_head))
 635                 return error(_("invalid orig-head: '%s'"), buf.buf);
 636
 637         if (file_exists(state_dir_path("quiet", opts)))
 638                 opts->flags &= ~REBASE_NO_QUIET;
 639         else
 640                 opts->flags |= REBASE_NO_QUIET;
 641
 642         if (file_exists(state_dir_path("verbose", opts)))
 643                 opts->flags |= REBASE_VERBOSE;
 644
 645         if (file_exists(state_dir_path("signoff", opts))) {
 646                 opts->signoff = 1;
 647                 opts->flags |= REBASE_FORCE;
 648         }
 649
 650         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 651                 strbuf_reset(&buf);
 652                 if (!read_oneliner(&buf, state_dir_path("allow_rerere_autoupdate", opts),
 653                                    READ_ONELINER_WARN_MISSING))
 654                         return -1;
 655                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
 656                         opts->allow_rerere_autoupdate = RERERE_AUTOUPDATE;
 657                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 658                         opts->allow_rerere_autoupdate = RERERE_NOAUTOUPDATE;
 659                 else
 660                         warning(_("ignoring invalid allow_rerere_autoupdate: "
 661                                   "'%s'"), buf.buf);
 662         }
 663
 664         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 665                 strbuf_reset(&buf);
 666                 if (!read_oneliner(&buf, state_dir_path("gpg_sign_opt", opts),
 667                                    READ_ONELINER_WARN_MISSING))
 668                         return -1;
 669                 free(opts->gpg_sign_opt);
 670                 opts->gpg_sign_opt = xstrdup(buf.buf);
 671         }
 672
 673         if (file_exists(state_dir_path("strategy", opts))) {
 674                 strbuf_reset(&buf);
 675                 if (!read_oneliner(&buf, state_dir_path("strategy", opts),
 676                                    READ_ONELINER_WARN_MISSING))
 677                         return -1;
 678                 free(opts->strategy);
 679                 opts->strategy = xstrdup(buf.buf);
 680         }
 681
 682         if (file_exists(state_dir_path("strategy_opts", opts))) {
 683                 strbuf_reset(&buf);
 684                 if (!read_oneliner(&buf, state_dir_path("strategy_opts", opts),
 685                                    READ_ONELINER_WARN_MISSING))
 686                         return -1;
 687                 free(opts->strategy_opts);
 688                 opts->strategy_opts = xstrdup(buf.buf);
 689         }
 690
 691         strbuf_release(&buf);
 692
 693         return 0;
 694 }
 695
 696 static int rebase_write_basic_state(struct rebase_options *opts)
 697 {
 698         write_file(state_dir_path("head-name", opts), "%s",
 699                    opts->head_name ? opts->head_name : "detached HEAD");
 700         write_file(state_dir_path("onto", opts), "%s",
 701                    opts->onto ? oid_to_hex(&opts->onto->object.oid) : "");
 702         write_file(state_dir_path("orig-head", opts), "%s",
 703                    oid_to_hex(&opts->orig_head));
 704         if (!(opts->flags & REBASE_NO_QUIET))
 705                 write_file(state_dir_path("quiet", opts), "%s", "");
 706         if (opts->flags & REBASE_VERBOSE)
 707                 write_file(state_dir_path("verbose", opts), "%s", "");
 708         if (opts->strategy)
 709                 write_file(state_dir_path("strategy", opts), "%s",
 710                            opts->strategy);
 711         if (opts->strategy_opts)
 712                 write_file(state_dir_path("strategy_opts", opts), "%s",
 713                            opts->strategy_opts);
 714         if (opts->allow_rerere_autoupdate > 0)
 715                 write_file(state_dir_path("allow_rerere_autoupdate", opts),
 716                            "-%s-rerere-autoupdate",
 717                            opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
 718                                 "" : "-no");
 719         if (opts->gpg_sign_opt)
 720                 write_file(state_dir_path("gpg_sign_opt", opts), "%s",
 721                            opts->gpg_sign_opt);
 722         if (opts->signoff)
 723                 write_file(state_dir_path("signoff", opts), "--signoff");
 724
 725         return 0;
 726 }
 727
 728 static int finish_rebase(struct rebase_options *opts)
 729 {
 730         struct strbuf dir = STRBUF_INIT;
 731         int ret = 0;
 732
 733         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 734         apply_autostash(state_dir_path("autostash", opts));
 735         close_object_store(the_repository->objects);
 736         /*
 737          * We ignore errors in 'gc --auto', since the
 738          * user should see them.
 739          */
 740         run_auto_gc(!(opts->flags & (REBASE_NO_QUIET|REBASE_VERBOSE)));
 741         if (opts->type == REBASE_MERGE) {
 742                 struct replay_opts replay = REPLAY_OPTS_INIT;
 743
 744                 replay.action = REPLAY_INTERACTIVE_REBASE;
 745                 ret = sequencer_remove_state(&replay);
 746         } else {
 747                 strbuf_addstr(&dir, opts->state_dir);
 748                 if (remove_dir_recursively(&dir, 0))
 749                         ret = error(_("could not remove '%s'"),
 750                                     opts->state_dir);
 751                 strbuf_release(&dir);
 752         }
 753
 754         return ret;
 755 }
 756
 757 static struct commit *peel_committish(const char *name)
 758 {
 759         struct object *obj;
 760         struct object_id oid;
 761
 762         if (get_oid(name, &oid))
 763                 return NULL;
 764         obj = parse_object(the_repository, &oid);
 765         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 766 }
 767
 768 static void add_var(struct strbuf *buf, const char *name, const char *value)
 769 {
 770         if (!value)
 771                 strbuf_addf(buf, "unset %s; ", name);
 772         else {
 773                 strbuf_addf(buf, "%s=", name);
 774                 sq_quote_buf(buf, value);
 775                 strbuf_addstr(buf, "; ");
 776         }
 777 }
 778
 779 static int move_to_original_branch(struct rebase_options *opts)
 780 {
 781         struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
 782         int ret;
 783
 784         if (!opts->head_name)
 785                 return 0; /* nothing to move back to */
 786
 787         if (!opts->onto)
 788                 BUG("move_to_original_branch without onto");
 789
 790         strbuf_addf(&orig_head_reflog, "rebase finished: %s onto %s",
 791                     opts->head_name, oid_to_hex(&opts->onto->object.oid));
 792         strbuf_addf(&head_reflog, "rebase finished: returning to %s",
 793                     opts->head_name);
 794         ret = reset_head(the_repository, NULL, "", opts->head_name,
 795                          RESET_HEAD_REFS_ONLY,
 796                          orig_head_reflog.buf, head_reflog.buf,
 797                          DEFAULT_REFLOG_ACTION);
 798
 799         strbuf_release(&orig_head_reflog);
 800         strbuf_release(&head_reflog);
 801         return ret;
 802 }
 803
 804 static const char *resolvemsg =
 805 N_("Resolve all conflicts manually, mark them as resolved with\n"
 806 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 807 "You can instead skip this commit: run \"git rebase --skip\".\n"
 808 "To abort and get back to the state before \"git rebase\", run "
 809 "\"git rebase --abort\".");
 810
 811 static int run_am(struct rebase_options *opts)
 812 {
 813         struct child_process am = CHILD_PROCESS_INIT;
 814         struct child_process format_patch = CHILD_PROCESS_INIT;
 815         struct strbuf revisions = STRBUF_INIT;
 816         int status;
 817         char *rebased_patches;
 818
 819         am.git_cmd = 1;
 820         strvec_push(&am.args, "am");
 821
 822         if (opts->action && !strcmp("continue", opts->action)) {
 823                 strvec_push(&am.args, "--resolved");
 824                 strvec_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 825                 if (opts->gpg_sign_opt)
 826                         strvec_push(&am.args, opts->gpg_sign_opt);
 827                 status = run_command(&am);
 828                 if (status)
 829                         return status;
 830
 831                 return move_to_original_branch(opts);
 832         }
 833         if (opts->action && !strcmp("skip", opts->action)) {
 834                 strvec_push(&am.args, "--skip");
 835                 strvec_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 836                 status = run_command(&am);
 837                 if (status)
 838                         return status;
 839
 840                 return move_to_original_branch(opts);
 841         }
 842         if (opts->action && !strcmp("show-current-patch", opts->action)) {
 843                 strvec_push(&am.args, "--show-current-patch");
 844                 return run_command(&am);
 845         }
 846
 847         strbuf_addf(&revisions, "%s...%s",
 848                     oid_to_hex(opts->root ?
 849                                /* this is now equivalent to !opts->upstream */
 850                                &opts->onto->object.oid :
 851                                &opts->upstream->object.oid),
 852                     oid_to_hex(&opts->orig_head));
 853
 854         rebased_patches = xstrdup(git_path("rebased-patches"));
 855         format_patch.out = open(rebased_patches,
 856                                 O_WRONLY | O_CREAT | O_TRUNC, 0666);
 857         if (format_patch.out < 0) {
 858                 status = error_errno(_("could not open '%s' for writing"),
 859                                      rebased_patches);
 860                 free(rebased_patches);
 861                 strvec_clear(&am.args);
 862                 return status;
 863         }
 864
 865         format_patch.git_cmd = 1;
 866         strvec_pushl(&format_patch.args, "format-patch", "-k", "--stdout",
 867                      "--full-index", "--cherry-pick", "--right-only",
 868                      "--src-prefix=a/", "--dst-prefix=b/", "--no-renames",
 869                      "--no-cover-letter", "--pretty=mboxrd", "--topo-order",
 870                      "--no-base", NULL);
 871         if (opts->git_format_patch_opt.len)
 872                 strvec_split(&format_patch.args,
 873                              opts->git_format_patch_opt.buf);
 874         strvec_push(&format_patch.args, revisions.buf);
 875         if (opts->restrict_revision)
 876                 strvec_pushf(&format_patch.args, "^%s",
 877                              oid_to_hex(&opts->restrict_revision->object.oid));
 878
 879         status = run_command(&format_patch);
 880         if (status) {
 881                 unlink(rebased_patches);
 882                 free(rebased_patches);
 883                 strvec_clear(&am.args);
 884
 885                 reset_head(the_repository, &opts->orig_head, "checkout",
 886                            opts->head_name, 0,
 887                            "HEAD", NULL, DEFAULT_REFLOG_ACTION);
 888                 error(_("\ngit encountered an error while preparing the "
 889                         "patches to replay\n"
 890                         "these revisions:\n"
 891                         "\n    %s\n\n"
 892                         "As a result, git cannot rebase them."),
 893                       opts->revisions);
 894
 895                 strbuf_release(&revisions);
 896                 return status;
 897         }
 898         strbuf_release(&revisions);
 899
 900         am.in = open(rebased_patches, O_RDONLY);
 901         if (am.in < 0) {
 902                 status = error_errno(_("could not open '%s' for reading"),
 903                                      rebased_patches);
 904                 free(rebased_patches);
 905                 strvec_clear(&am.args);
 906                 return status;
 907         }
 908
 909         strvec_pushv(&am.args, opts->git_am_opts.v);
 910         strvec_push(&am.args, "--rebasing");
 911         strvec_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 912         strvec_push(&am.args, "--patch-format=mboxrd");
 913         if (opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE)
 914                 strvec_push(&am.args, "--rerere-autoupdate");
 915         else if (opts->allow_rerere_autoupdate == RERERE_NOAUTOUPDATE)
 916                 strvec_push(&am.args, "--no-rerere-autoupdate");
 917         if (opts->gpg_sign_opt)
 918                 strvec_push(&am.args, opts->gpg_sign_opt);
 919         status = run_command(&am);
 920         unlink(rebased_patches);
 921         free(rebased_patches);
 922
 923         if (!status) {
 924                 return move_to_original_branch(opts);
 925         }
 926
 927         if (is_directory(opts->state_dir))
 928                 rebase_write_basic_state(opts);
 929
 930         return status;
 931 }
 932
 933 static int run_specific_rebase(struct rebase_options *opts, enum action action)
 934 {
 935         const char *argv[] = { NULL, NULL };
 936         struct strbuf script_snippet = STRBUF_INIT, buf = STRBUF_INIT;
 937         int status;
 938         const char *backend, *backend_func;
 939
 940         if (opts->type == REBASE_MERGE) {
 941                 /* Run sequencer-based rebase */
 942                 setenv("GIT_CHERRY_PICK_HELP", resolvemsg, 1);
 943                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 944                         setenv("GIT_SEQUENCE_EDITOR", ":", 1);
 945                         opts->autosquash = 0;
 946                 }
 947                 if (opts->gpg_sign_opt) {
 948                         /* remove the leading "-S" */
 949                         char *tmp = xstrdup(opts->gpg_sign_opt + 2);
 950                         free(opts->gpg_sign_opt);
 951                         opts->gpg_sign_opt = tmp;
 952                 }
 953
 954                 status = run_sequencer_rebase(opts, action);
 955                 goto finished_rebase;
 956         }
 957
 958         if (opts->type == REBASE_APPLY) {
 959                 status = run_am(opts);
 960                 goto finished_rebase;
 961         }
 962
 963         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 964         add_var(&script_snippet, "state_dir", opts->state_dir);
 965
 966         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 967         add_var(&script_snippet, "upstream", opts->upstream ?
 968                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 969         add_var(&script_snippet, "head_name",
 970                 opts->head_name ? opts->head_name : "detached HEAD");
 971         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 972         add_var(&script_snippet, "onto", opts->onto ?
 973                 oid_to_hex(&opts->onto->object.oid) : NULL);
 974         add_var(&script_snippet, "onto_name", opts->onto_name);
 975         add_var(&script_snippet, "revisions", opts->revisions);
 976         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 977                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 978         sq_quote_argv_pretty(&buf, opts->git_am_opts.v);
 979         add_var(&script_snippet, "git_am_opt", buf.buf);
 980         strbuf_release(&buf);
 981         add_var(&script_snippet, "verbose",
 982                 opts->flags & REBASE_VERBOSE ? "t" : "");
 983         add_var(&script_snippet, "diffstat",
 984                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 985         add_var(&script_snippet, "force_rebase",
 986                 opts->flags & REBASE_FORCE ? "t" : "");
 987         if (opts->switch_to)
 988                 add_var(&script_snippet, "switch_to", opts->switch_to);
 989         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 990         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 991         add_var(&script_snippet, "allow_rerere_autoupdate",
 992                 opts->allow_rerere_autoupdate ?
 993                         opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
 994                         "--rerere-autoupdate" : "--no-rerere-autoupdate" : "");
 995         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
 996         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
 997         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
 998         add_var(&script_snippet, "cmd", opts->cmd);
 999         add_var(&script_snippet, "allow_empty_message",
1000                 opts->allow_empty_message ?  "--allow-empty-message" : "");
1001         add_var(&script_snippet, "rebase_merges",
1002                 opts->rebase_merges ? "t" : "");
1003         add_var(&script_snippet, "rebase_cousins",
1004                 opts->rebase_cousins ? "t" : "");
1005         add_var(&script_snippet, "strategy", opts->strategy);
1006         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
1007         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
1008         add_var(&script_snippet, "squash_onto",
1009                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
1010         add_var(&script_snippet, "git_format_patch_opt",
1011                 opts->git_format_patch_opt.buf);
1012
1013         if (is_merge(opts) &&
1014             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
1015                 strbuf_addstr(&script_snippet,
1016                               "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
1017                 opts->autosquash = 0;
1018         }
1019
1020         switch (opts->type) {
1021         case REBASE_PRESERVE_MERGES:
1022                 backend = "git-rebase--preserve-merges";
1023                 backend_func = "git_rebase__preserve_merges";
1024                 break;
1025         default:
1026                 BUG("Unhandled rebase type %d", opts->type);
1027                 break;
1028         }
1029
1030         strbuf_addf(&script_snippet,
1031                     ". git-sh-setup && . %s && %s", backend, backend_func);
1032         argv[0] = script_snippet.buf;
1033
1034         status = run_command_v_opt(argv, RUN_USING_SHELL);
1035 finished_rebase:
1036         if (opts->dont_finish_rebase)
1037                 ; /* do nothing */
1038         else if (opts->type == REBASE_MERGE)
1039                 ; /* merge backend cleans up after itself */
1040         else if (status == 0) {
1041                 if (!file_exists(state_dir_path("stopped-sha", opts)))
1042                         finish_rebase(opts);
1043         } else if (status == 2) {
1044                 struct strbuf dir = STRBUF_INIT;
1045
1046                 apply_autostash(state_dir_path("autostash", opts));
1047                 strbuf_addstr(&dir, opts->state_dir);
1048                 remove_dir_recursively(&dir, 0);
1049                 strbuf_release(&dir);
1050                 die("Nothing to do");
1051         }
1052
1053         strbuf_release(&script_snippet);
1054
1055         return status ? -1 : 0;
1056 }
1057
1058 static int rebase_config(const char *var, const char *value, void *data)
1059 {
1060         struct rebase_options *opts = data;
1061
1062         if (!strcmp(var, "rebase.stat")) {
1063                 if (git_config_bool(var, value))
1064                         opts->flags |= REBASE_DIFFSTAT;
1065                 else
1066                         opts->flags &= ~REBASE_DIFFSTAT;
1067                 return 0;
1068         }
1069
1070         if (!strcmp(var, "rebase.autosquash")) {
1071                 opts->autosquash = git_config_bool(var, value);
1072                 return 0;
1073         }
1074
1075         if (!strcmp(var, "commit.gpgsign")) {
1076                 free(opts->gpg_sign_opt);
1077                 opts->gpg_sign_opt = git_config_bool(var, value) ?
1078                         xstrdup("-S") : NULL;
1079                 return 0;
1080         }
1081
1082         if (!strcmp(var, "rebase.autostash")) {
1083                 opts->autostash = git_config_bool(var, value);
1084                 return 0;
1085         }
1086
1087         if (!strcmp(var, "rebase.reschedulefailedexec")) {
1088                 opts->reschedule_failed_exec = git_config_bool(var, value);
1089                 return 0;
1090         }
1091
1092         if (!strcmp(var, "rebase.usebuiltin")) {
1093                 opts->use_legacy_rebase = !git_config_bool(var, value);
1094                 return 0;
1095         }
1096
1097         if (!strcmp(var, "rebase.backend")) {
1098                 return git_config_string(&opts->default_backend, var, value);
1099         }
1100
1101         return git_default_config(var, value, data);
1102 }
1103
1104 /*
1105  * Determines whether the commits in from..to are linear, i.e. contain
1106  * no merge commits. This function *expects* `from` to be an ancestor of
1107  * `to`.
1108  */
1109 static int is_linear_history(struct commit *from, struct commit *to)
1110 {
1111         while (to && to != from) {
1112                 parse_commit(to);
1113                 if (!to->parents)
1114                         return 1;
1115                 if (to->parents->next)
1116                         return 0;
1117                 to = to->parents->item;
1118         }
1119         return 1;
1120 }
1121
1122 static int can_fast_forward(struct commit *onto, struct commit *upstream,
1123                             struct commit *restrict_revision,
1124                             struct object_id *head_oid, struct object_id *merge_base)
1125 {
1126         struct commit *head = lookup_commit(the_repository, head_oid);
1127         struct commit_list *merge_bases = NULL;
1128         int res = 0;
1129
1130         if (!head)
1131                 goto done;
1132
1133         merge_bases = get_merge_bases(onto, head);
1134         if (!merge_bases || merge_bases->next) {
1135                 oidcpy(merge_base, &null_oid);
1136                 goto done;
1137         }
1138
1139         oidcpy(merge_base, &merge_bases->item->object.oid);
1140         if (!oideq(merge_base, &onto->object.oid))
1141                 goto done;
1142
1143         if (restrict_revision && !oideq(&restrict_revision->object.oid, merge_base))
1144                 goto done;
1145
1146         if (!upstream)
1147                 goto done;
1148
1149         free_commit_list(merge_bases);
1150         merge_bases = get_merge_bases(upstream, head);
1151         if (!merge_bases || merge_bases->next)
1152                 goto done;
1153
1154         if (!oideq(&onto->object.oid, &merge_bases->item->object.oid))
1155                 goto done;
1156
1157         res = 1;
1158
1159 done:
1160         free_commit_list(merge_bases);
1161         return res && is_linear_history(onto, head);
1162 }
1163
1164 static int parse_opt_am(const struct option *opt, const char *arg, int unset)
1165 {
1166         struct rebase_options *opts = opt->value;
1167
1168         BUG_ON_OPT_NEG(unset);
1169         BUG_ON_OPT_ARG(arg);
1170
1171         opts->type = REBASE_APPLY;
1172
1173         return 0;
1174 }
1175
1176 /* -i followed by -m is still -i */
1177 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
1178 {
1179         struct rebase_options *opts = opt->value;
1180
1181         BUG_ON_OPT_NEG(unset);
1182         BUG_ON_OPT_ARG(arg);
1183
1184         if (!is_merge(opts))
1185                 opts->type = REBASE_MERGE;
1186
1187         return 0;
1188 }
1189
1190 /* -i followed by -p is still explicitly interactive, but -p alone is not */
1191 static int parse_opt_interactive(const struct option *opt, const char *arg,
1192                                  int unset)
1193 {
1194         struct rebase_options *opts = opt->value;
1195
1196         BUG_ON_OPT_NEG(unset);
1197         BUG_ON_OPT_ARG(arg);
1198
1199         opts->type = REBASE_MERGE;
1200         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
1201
1202         return 0;
1203 }
1204
1205 static enum empty_type parse_empty_value(const char *value)
1206 {
1207         if (!strcasecmp(value, "drop"))
1208                 return EMPTY_DROP;
1209         else if (!strcasecmp(value, "keep"))
1210                 return EMPTY_KEEP;
1211         else if (!strcasecmp(value, "ask"))
1212                 return EMPTY_ASK;
1213
1214         die(_("unrecognized empty type '%s'; valid values are \"drop\", \"keep\", and \"ask\"."), value);
1215 }
1216
1217 static int parse_opt_empty(const struct option *opt, const char *arg, int unset)
1218 {
1219         struct rebase_options *options = opt->value;
1220         enum empty_type value = parse_empty_value(arg);
1221
1222         BUG_ON_OPT_NEG(unset);
1223
1224         options->empty = value;
1225         return 0;
1226 }
1227
1228 static void NORETURN error_on_missing_default_upstream(void)
1229 {
1230         struct branch *current_branch = branch_get(NULL);
1231
1232         printf(_("%s\n"
1233                  "Please specify which branch you want to rebase against.\n"
1234                  "See git-rebase(1) for details.\n"
1235                  "\n"
1236                  "    git rebase '<branch>'\n"
1237                  "\n"),
1238                 current_branch ? _("There is no tracking information for "
1239                         "the current branch.") :
1240                         _("You are not currently on a branch."));
1241
1242         if (current_branch) {
1243                 const char *remote = current_branch->remote_name;
1244
1245                 if (!remote)
1246                         remote = _("<remote>");
1247
1248                 printf(_("If you wish to set tracking information for this "
1249                          "branch you can do so with:\n"
1250                          "\n"
1251                          "    git branch --set-upstream-to=%s/<branch> %s\n"
1252                          "\n"),
1253                        remote, current_branch->name);
1254         }
1255         exit(1);
1256 }
1257
1258 static void set_reflog_action(struct rebase_options *options)
1259 {
1260         const char *env;
1261         struct strbuf buf = STRBUF_INIT;
1262
1263         if (!is_merge(options))
1264                 return;
1265
1266         env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
1267         if (env && strcmp("rebase", env))
1268                 return; /* only override it if it is "rebase" */
1269
1270         strbuf_addf(&buf, "rebase (%s)", options->action);
1271         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, buf.buf, 1);
1272         strbuf_release(&buf);
1273 }
1274
1275 static int check_exec_cmd(const char *cmd)
1276 {
1277         if (strchr(cmd, '\n'))
1278                 return error(_("exec commands cannot contain newlines"));
1279
1280         /* Does the command consist purely of whitespace? */
1281         if (!cmd[strspn(cmd, " \t\r\f\v")])
1282                 return error(_("empty exec command"));
1283
1284         return 0;
1285 }
1286
1287 int cmd_rebase(int argc, const char **argv, const char *prefix)
1288 {
1289         struct rebase_options options = REBASE_OPTIONS_INIT;
1290         const char *branch_name;
1291         int ret, flags, total_argc, in_progress = 0;
1292         int keep_base = 0;
1293         int ok_to_skip_pre_rebase = 0;
1294         struct strbuf msg = STRBUF_INIT;
1295         struct strbuf revisions = STRBUF_INIT;
1296         struct strbuf buf = STRBUF_INIT;
1297         struct object_id merge_base;
1298         int ignore_whitespace = 0;
1299         enum action action = ACTION_NONE;
1300         const char *gpg_sign = NULL;
1301         struct string_list exec = STRING_LIST_INIT_NODUP;
1302         const char *rebase_merges = NULL;
1303         int fork_point = -1;
1304         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
1305         struct object_id squash_onto;
1306         char *squash_onto_name = NULL;
1307         int reschedule_failed_exec = -1;
1308         int allow_preemptive_ff = 1;
1309         struct option builtin_rebase_options[] = {
1310                 OPT_STRING(0, "onto", &options.onto_name,
1311                            N_("revision"),
1312                            N_("rebase onto given branch instead of upstream")),
1313                 OPT_BOOL(0, "keep-base", &keep_base,
1314                          N_("use the merge-base of upstream and branch as the current base")),
1315                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
1316                          N_("allow pre-rebase hook to run")),
1317                 OPT_NEGBIT('q', "quiet", &options.flags,
1318                            N_("be quiet. implies --no-stat"),
1319                            REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
1320                 OPT_BIT('v', "verbose", &options.flags,
1321                         N_("display a diffstat of what changed upstream"),
1322                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
1323                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
1324                         N_("do not show diffstat of what changed upstream"),
1325                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
1326                 OPT_BOOL(0, "signoff", &options.signoff,
1327                          N_("add a Signed-off-by: line to each commit")),
1328                 OPT_BOOL(0, "committer-date-is-author-date",
1329                          &options.committer_date_is_author_date,
1330                          N_("make committer date match author date")),
1331                 OPT_BOOL(0, "reset-author-date", &options.ignore_date,
1332                          N_("ignore author date and use current date")),
1333                 OPT_HIDDEN_BOOL(0, "ignore-date", &options.ignore_date,
1334                                 N_("synonym of --reset-author-date")),
1335                 OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
1336                                   N_("passed to 'git apply'"), 0),
1337                 OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
1338                          N_("ignore changes in whitespace")),
1339                 OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
1340                                   N_("action"), N_("passed to 'git apply'"), 0),
1341                 OPT_BIT('f', "force-rebase", &options.flags,
1342                         N_("cherry-pick all commits, even if unchanged"),
1343                         REBASE_FORCE),
1344                 OPT_BIT(0, "no-ff", &options.flags,
1345                         N_("cherry-pick all commits, even if unchanged"),
1346                         REBASE_FORCE),
1347                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
1348                             ACTION_CONTINUE),
1349                 OPT_CMDMODE(0, "skip", &action,
1350                             N_("skip current patch and continue"), ACTION_SKIP),
1351                 OPT_CMDMODE(0, "abort", &action,
1352                             N_("abort and check out the original branch"),
1353                             ACTION_ABORT),
1354                 OPT_CMDMODE(0, "quit", &action,
1355                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
1356                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
1357                             "during an interactive rebase"), ACTION_EDIT_TODO),
1358                 OPT_CMDMODE(0, "show-current-patch", &action,
1359                             N_("show the patch file being applied or merged"),
1360                             ACTION_SHOW_CURRENT_PATCH),
1361                 OPT_CALLBACK_F(0, "apply", &options, NULL,
1362                         N_("use apply strategies to rebase"),
1363                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1364                         parse_opt_am),
1365                 OPT_CALLBACK_F('m', "merge", &options, NULL,
1366                         N_("use merging strategies to rebase"),
1367                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1368                         parse_opt_merge),
1369                 OPT_CALLBACK_F('i', "interactive", &options, NULL,
1370                         N_("let the user edit the list of commits to rebase"),
1371                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1372                         parse_opt_interactive),
1373                 OPT_SET_INT_F('p', "preserve-merges", &options.type,
1374                               N_("(DEPRECATED) try to recreate merges instead of "
1375                                  "ignoring them"),
1376                               REBASE_PRESERVE_MERGES, PARSE_OPT_HIDDEN),
1377                 OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
1378                 OPT_CALLBACK_F(0, "empty", &options, "{drop,keep,ask}",
1379                                N_("how to handle commits that become empty"),
1380                                PARSE_OPT_NONEG, parse_opt_empty),
1381                 OPT_CALLBACK_F('k', "keep-empty", &options, NULL,
1382                         N_("keep commits which start empty"),
1383                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
1384                         parse_opt_keep_empty),
1385                 OPT_BOOL(0, "autosquash", &options.autosquash,
1386                          N_("move commits that begin with "
1387                             "squash!/fixup! under -i")),
1388                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
1389                         N_("GPG-sign commits"),
1390                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
1391                 OPT_AUTOSTASH(&options.autostash),
1392                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
1393                                 N_("add exec lines after each commit of the "
1394                                    "editable list")),
1395                 OPT_BOOL_F(0, "allow-empty-message",
1396                            &options.allow_empty_message,
1397                            N_("allow rebasing commits with empty messages"),
1398                            PARSE_OPT_HIDDEN),
1399                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
1400                         N_("mode"),
1401                         N_("try to rebase merges instead of skipping them"),
1402                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
1403                 OPT_BOOL(0, "fork-point", &fork_point,
1404                          N_("use 'merge-base --fork-point' to refine upstream")),
1405                 OPT_STRING('s', "strategy", &options.strategy,
1406                            N_("strategy"), N_("use the given merge strategy")),
1407                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
1408                                 N_("option"),
1409                                 N_("pass the argument through to the merge "
1410                                    "strategy")),
1411                 OPT_BOOL(0, "root", &options.root,
1412                          N_("rebase all reachable commits up to the root(s)")),
1413                 OPT_BOOL(0, "reschedule-failed-exec",
1414                          &reschedule_failed_exec,
1415                          N_("automatically re-schedule any `exec` that fails")),
1416                 OPT_BOOL(0, "reapply-cherry-picks", &options.reapply_cherry_picks,
1417                          N_("apply all changes, even those already present upstream")),
1418                 OPT_END(),
1419         };
1420         int i;
1421
1422         if (argc == 2 && !strcmp(argv[1], "-h"))
1423                 usage_with_options(builtin_rebase_usage,
1424                                    builtin_rebase_options);
1425
1426         options.allow_empty_message = 1;
1427         git_config(rebase_config, &options);
1428         /* options.gpg_sign_opt will be either "-S" or NULL */
1429         gpg_sign = options.gpg_sign_opt ? "" : NULL;
1430         FREE_AND_NULL(options.gpg_sign_opt);
1431
1432         if (options.use_legacy_rebase ||
1433             !git_env_bool("GIT_TEST_REBASE_USE_BUILTIN", -1))
1434                 warning(_("the rebase.useBuiltin support has been removed!\n"
1435                           "See its entry in 'git help config' for details."));
1436
1437         strbuf_reset(&buf);
1438         strbuf_addf(&buf, "%s/applying", apply_dir());
1439         if(file_exists(buf.buf))
1440                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
1441
1442         if (is_directory(apply_dir())) {
1443                 options.type = REBASE_APPLY;
1444                 options.state_dir = apply_dir();
1445         } else if (is_directory(merge_dir())) {
1446                 strbuf_reset(&buf);
1447                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
1448                 if (is_directory(buf.buf)) {
1449                         options.type = REBASE_PRESERVE_MERGES;
1450                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1451                 } else {
1452                         strbuf_reset(&buf);
1453                         strbuf_addf(&buf, "%s/interactive", merge_dir());
1454                         if(file_exists(buf.buf)) {
1455                                 options.type = REBASE_MERGE;
1456                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1457                         } else
1458                                 options.type = REBASE_MERGE;
1459                 }
1460                 options.state_dir = merge_dir();
1461         }
1462
1463         if (options.type != REBASE_UNSPECIFIED)
1464                 in_progress = 1;
1465
1466         total_argc = argc;
1467         argc = parse_options(argc, argv, prefix,
1468                              builtin_rebase_options,
1469                              builtin_rebase_usage, 0);
1470
1471         if (action != ACTION_NONE && total_argc != 2) {
1472                 usage_with_options(builtin_rebase_usage,
1473                                    builtin_rebase_options);
1474         }
1475
1476         if (argc > 2)
1477                 usage_with_options(builtin_rebase_usage,
1478                                    builtin_rebase_options);
1479
1480         if (options.type == REBASE_PRESERVE_MERGES)
1481                 warning(_("git rebase --preserve-merges is deprecated. "
1482                           "Use --rebase-merges instead."));
1483
1484         if (keep_base) {
1485                 if (options.onto_name)
1486                         die(_("cannot combine '--keep-base' with '--onto'"));
1487                 if (options.root)
1488                         die(_("cannot combine '--keep-base' with '--root'"));
1489         }
1490
1491         if (options.root && fork_point > 0)
1492                 die(_("cannot combine '--root' with '--fork-point'"));
1493
1494         if (action != ACTION_NONE && !in_progress)
1495                 die(_("No rebase in progress?"));
1496         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
1497
1498         if (action == ACTION_EDIT_TODO && !is_merge(&options))
1499                 die(_("The --edit-todo action can only be used during "
1500                       "interactive rebase."));
1501
1502         if (trace2_is_enabled()) {
1503                 if (is_merge(&options))
1504                         trace2_cmd_mode("interactive");
1505                 else if (exec.nr)
1506                         trace2_cmd_mode("interactive-exec");
1507                 else
1508                         trace2_cmd_mode(action_names[action]);
1509         }
1510
1511         switch (action) {
1512         case ACTION_CONTINUE: {
1513                 struct object_id head;
1514                 struct lock_file lock_file = LOCK_INIT;
1515                 int fd;
1516
1517                 options.action = "continue";
1518                 set_reflog_action(&options);
1519
1520                 /* Sanity check */
1521                 if (get_oid("HEAD", &head))
1522                         die(_("Cannot read HEAD"));
1523
1524                 fd = hold_locked_index(&lock_file, 0);
1525                 if (repo_read_index(the_repository) < 0)
1526                         die(_("could not read index"));
1527                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
1528                               NULL);
1529                 if (0 <= fd)
1530                         repo_update_index_if_able(the_repository, &lock_file);
1531                 rollback_lock_file(&lock_file);
1532
1533                 if (has_unstaged_changes(the_repository, 1)) {
1534                         puts(_("You must edit all merge conflicts and then\n"
1535                                "mark them as resolved using git add"));
1536                         exit(1);
1537                 }
1538                 if (read_basic_state(&options))
1539                         exit(1);
1540                 goto run_rebase;
1541         }
1542         case ACTION_SKIP: {
1543                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1544
1545                 options.action = "skip";
1546                 set_reflog_action(&options);
1547
1548                 rerere_clear(the_repository, &merge_rr);
1549                 string_list_clear(&merge_rr, 1);
1550
1551                 if (reset_head(the_repository, NULL, "reset", NULL, RESET_HEAD_HARD,
1552                                NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
1553                         die(_("could not discard worktree changes"));
1554                 remove_branch_state(the_repository, 0);
1555                 if (read_basic_state(&options))
1556                         exit(1);
1557                 goto run_rebase;
1558         }
1559         case ACTION_ABORT: {
1560                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1561                 options.action = "abort";
1562                 set_reflog_action(&options);
1563
1564                 rerere_clear(the_repository, &merge_rr);
1565                 string_list_clear(&merge_rr, 1);
1566
1567                 if (read_basic_state(&options))
1568                         exit(1);
1569                 if (reset_head(the_repository, &options.orig_head, "reset",
1570                                options.head_name, RESET_HEAD_HARD,
1571                                NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
1572                         die(_("could not move back to %s"),
1573                             oid_to_hex(&options.orig_head));
1574                 remove_branch_state(the_repository, 0);
1575                 ret = !!finish_rebase(&options);
1576                 goto cleanup;
1577         }
1578         case ACTION_QUIT: {
1579                 save_autostash(state_dir_path("autostash", &options));
1580                 if (options.type == REBASE_MERGE) {
1581                         struct replay_opts replay = REPLAY_OPTS_INIT;
1582
1583                         replay.action = REPLAY_INTERACTIVE_REBASE;
1584                         ret = !!sequencer_remove_state(&replay);
1585                 } else {
1586                         strbuf_reset(&buf);
1587                         strbuf_addstr(&buf, options.state_dir);
1588                         ret = !!remove_dir_recursively(&buf, 0);
1589                         if (ret)
1590                                 error(_("could not remove '%s'"),
1591                                        options.state_dir);
1592                 }
1593                 goto cleanup;
1594         }
1595         case ACTION_EDIT_TODO:
1596                 options.action = "edit-todo";
1597                 options.dont_finish_rebase = 1;
1598                 goto run_rebase;
1599         case ACTION_SHOW_CURRENT_PATCH:
1600                 options.action = "show-current-patch";
1601                 options.dont_finish_rebase = 1;
1602                 goto run_rebase;
1603         case ACTION_NONE:
1604                 break;
1605         default:
1606                 BUG("action: %d", action);
1607         }
1608
1609         /* Make sure no rebase is in progress */
1610         if (in_progress) {
1611                 const char *last_slash = strrchr(options.state_dir, '/');
1612                 const char *state_dir_base =
1613                         last_slash ? last_slash + 1 : options.state_dir;
1614                 const char *cmd_live_rebase =
1615                         "git rebase (--continue | --abort | --skip)";
1616                 strbuf_reset(&buf);
1617                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1618                 die(_("It seems that there is already a %s directory, and\n"
1619                       "I wonder if you are in the middle of another rebase.  "
1620                       "If that is the\n"
1621                       "case, please try\n\t%s\n"
1622                       "If that is not the case, please\n\t%s\n"
1623                       "and run me again.  I am stopping in case you still "
1624                       "have something\n"
1625                       "valuable there.\n"),
1626                     state_dir_base, cmd_live_rebase, buf.buf);
1627         }
1628
1629         if ((options.flags & REBASE_INTERACTIVE_EXPLICIT) ||
1630             (action != ACTION_NONE) ||
1631             (exec.nr > 0) ||
1632             options.autosquash) {
1633                 allow_preemptive_ff = 0;
1634         }
1635         if (options.committer_date_is_author_date || options.ignore_date)
1636                 options.flags |= REBASE_FORCE;
1637
1638         for (i = 0; i < options.git_am_opts.nr; i++) {
1639                 const char *option = options.git_am_opts.v[i], *p;
1640                 if (!strcmp(option, "--whitespace=fix") ||
1641                     !strcmp(option, "--whitespace=strip"))
1642                         allow_preemptive_ff = 0;
1643                 else if (skip_prefix(option, "-C", &p)) {
1644                         while (*p)
1645                                 if (!isdigit(*(p++)))
1646                                         die(_("switch `C' expects a "
1647                                               "numerical value"));
1648                 } else if (skip_prefix(option, "--whitespace=", &p)) {
1649                         if (*p && strcmp(p, "warn") && strcmp(p, "nowarn") &&
1650                             strcmp(p, "error") && strcmp(p, "error-all"))
1651                                 die("Invalid whitespace option: '%s'", p);
1652                 }
1653         }
1654
1655         for (i = 0; i < exec.nr; i++)
1656                 if (check_exec_cmd(exec.items[i].string))
1657                         exit(1);
1658
1659         if (!(options.flags & REBASE_NO_QUIET))
1660                 strvec_push(&options.git_am_opts, "-q");
1661
1662         if (options.empty != EMPTY_UNSPECIFIED)
1663                 imply_merge(&options, "--empty");
1664
1665         if (options.reapply_cherry_picks)
1666                 imply_merge(&options, "--reapply-cherry-picks");
1667
1668         if (gpg_sign)
1669                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1670
1671         if (exec.nr) {
1672                 int i;
1673
1674                 imply_merge(&options, "--exec");
1675
1676                 strbuf_reset(&buf);
1677                 for (i = 0; i < exec.nr; i++)
1678                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1679                 options.cmd = xstrdup(buf.buf);
1680         }
1681
1682         if (rebase_merges) {
1683                 if (!*rebase_merges)
1684                         ; /* default mode; do nothing */
1685                 else if (!strcmp("rebase-cousins", rebase_merges))
1686                         options.rebase_cousins = 1;
1687                 else if (strcmp("no-rebase-cousins", rebase_merges))
1688                         die(_("Unknown mode: %s"), rebase_merges);
1689                 options.rebase_merges = 1;
1690                 imply_merge(&options, "--rebase-merges");
1691         }
1692
1693         if (options.type == REBASE_APPLY) {
1694                 if (ignore_whitespace)
1695                         strvec_push(&options.git_am_opts,
1696                                     "--ignore-whitespace");
1697                 if (options.committer_date_is_author_date)
1698                         strvec_push(&options.git_am_opts,
1699                                     "--committer-date-is-author-date");
1700                 if (options.ignore_date)
1701                         strvec_push(&options.git_am_opts, "--ignore-date");
1702         } else {
1703                 /* REBASE_MERGE and PRESERVE_MERGES */
1704                 if (ignore_whitespace) {
1705                         string_list_append(&strategy_options,
1706                                            "ignore-space-change");
1707                 }
1708         }
1709
1710         if (strategy_options.nr) {
1711                 int i;
1712
1713                 if (!options.strategy)
1714                         options.strategy = "recursive";
1715
1716                 strbuf_reset(&buf);
1717                 for (i = 0; i < strategy_options.nr; i++)
1718                         strbuf_addf(&buf, " --%s",
1719                                     strategy_options.items[i].string);
1720                 options.strategy_opts = xstrdup(buf.buf);
1721         }
1722
1723         if (options.strategy) {
1724                 options.strategy = xstrdup(options.strategy);
1725                 switch (options.type) {
1726                 case REBASE_APPLY:
1727                         die(_("--strategy requires --merge or --interactive"));
1728                 case REBASE_MERGE:
1729                 case REBASE_PRESERVE_MERGES:
1730                         /* compatible */
1731                         break;
1732                 case REBASE_UNSPECIFIED:
1733                         options.type = REBASE_MERGE;
1734                         break;
1735                 default:
1736                         BUG("unhandled rebase type (%d)", options.type);
1737                 }
1738         }
1739
1740         if (options.type == REBASE_MERGE)
1741                 imply_merge(&options, "--merge");
1742
1743         if (options.root && !options.onto_name)
1744                 imply_merge(&options, "--root without --onto");
1745
1746         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1747                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1748
1749         if (options.git_am_opts.nr || options.type == REBASE_APPLY) {
1750                 /* all am options except -q are compatible only with --apply */
1751                 for (i = options.git_am_opts.nr - 1; i >= 0; i--)
1752                         if (strcmp(options.git_am_opts.v[i], "-q"))
1753                                 break;
1754
1755                 if (i >= 0) {
1756                         if (is_merge(&options))
1757                                 die(_("cannot combine apply options with "
1758                                       "merge options"));
1759                         else
1760                                 options.type = REBASE_APPLY;
1761                 }
1762         }
1763
1764         if (options.type == REBASE_UNSPECIFIED) {
1765                 if (!strcmp(options.default_backend, "merge"))
1766                         imply_merge(&options, "--merge");
1767                 else if (!strcmp(options.default_backend, "apply"))
1768                         options.type = REBASE_APPLY;
1769                 else
1770                         die(_("Unknown rebase backend: %s"),
1771                             options.default_backend);
1772         }
1773
1774         switch (options.type) {
1775         case REBASE_MERGE:
1776         case REBASE_PRESERVE_MERGES:
1777                 options.state_dir = merge_dir();
1778                 break;
1779         case REBASE_APPLY:
1780                 options.state_dir = apply_dir();
1781                 break;
1782         default:
1783                 BUG("options.type was just set above; should be unreachable.");
1784         }
1785
1786         if (options.empty == EMPTY_UNSPECIFIED) {
1787                 if (options.flags & REBASE_INTERACTIVE_EXPLICIT)
1788                         options.empty = EMPTY_ASK;
1789                 else if (exec.nr > 0)
1790                         options.empty = EMPTY_KEEP;
1791                 else
1792                         options.empty = EMPTY_DROP;
1793         }
1794         if (reschedule_failed_exec > 0 && !is_merge(&options))
1795                 die(_("--reschedule-failed-exec requires "
1796                       "--exec or --interactive"));
1797         if (reschedule_failed_exec >= 0)
1798                 options.reschedule_failed_exec = reschedule_failed_exec;
1799
1800         if (options.signoff) {
1801                 if (options.type == REBASE_PRESERVE_MERGES)
1802                         die("cannot combine '--signoff' with "
1803                             "'--preserve-merges'");
1804                 strvec_push(&options.git_am_opts, "--signoff");
1805                 options.flags |= REBASE_FORCE;
1806         }
1807
1808         if (options.type == REBASE_PRESERVE_MERGES) {
1809                 /*
1810                  * Note: incompatibility with --signoff handled in signoff block above
1811                  * Note: incompatibility with --interactive is just a strong warning;
1812                  *       git-rebase.txt caveats with "unless you know what you are doing"
1813                  */
1814                 if (options.rebase_merges)
1815                         die(_("cannot combine '--preserve-merges' with "
1816                               "'--rebase-merges'"));
1817
1818                 if (options.reschedule_failed_exec)
1819                         die(_("error: cannot combine '--preserve-merges' with "
1820                               "'--reschedule-failed-exec'"));
1821         }
1822
1823         if (!options.root) {
1824                 if (argc < 1) {
1825                         struct branch *branch;
1826
1827                         branch = branch_get(NULL);
1828                         options.upstream_name = branch_get_upstream(branch,
1829                                                                     NULL);
1830                         if (!options.upstream_name)
1831                                 error_on_missing_default_upstream();
1832                         if (fork_point < 0)
1833                                 fork_point = 1;
1834                 } else {
1835                         options.upstream_name = argv[0];
1836                         argc--;
1837                         argv++;
1838                         if (!strcmp(options.upstream_name, "-"))
1839                                 options.upstream_name = "@{-1}";
1840                 }
1841                 options.upstream = peel_committish(options.upstream_name);
1842                 if (!options.upstream)
1843                         die(_("invalid upstream '%s'"), options.upstream_name);
1844                 options.upstream_arg = options.upstream_name;
1845         } else {
1846                 if (!options.onto_name) {
1847                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1848                                         &squash_onto, NULL, NULL) < 0)
1849                                 die(_("Could not create new root commit"));
1850                         options.squash_onto = &squash_onto;
1851                         options.onto_name = squash_onto_name =
1852                                 xstrdup(oid_to_hex(&squash_onto));
1853                 } else
1854                         options.root_with_onto = 1;
1855
1856                 options.upstream_name = NULL;
1857                 options.upstream = NULL;
1858                 if (argc > 1)
1859                         usage_with_options(builtin_rebase_usage,
1860                                            builtin_rebase_options);
1861                 options.upstream_arg = "--root";
1862         }
1863
1864         /* Make sure the branch to rebase onto is valid. */
1865         if (keep_base) {
1866                 strbuf_reset(&buf);
1867                 strbuf_addstr(&buf, options.upstream_name);
1868                 strbuf_addstr(&buf, "...");
1869                 options.onto_name = xstrdup(buf.buf);
1870         } else if (!options.onto_name)
1871                 options.onto_name = options.upstream_name;
1872         if (strstr(options.onto_name, "...")) {
1873                 if (get_oid_mb(options.onto_name, &merge_base) < 0) {
1874                         if (keep_base)
1875                                 die(_("'%s': need exactly one merge base with branch"),
1876                                     options.upstream_name);
1877                         else
1878                                 die(_("'%s': need exactly one merge base"),
1879                                     options.onto_name);
1880                 }
1881                 options.onto = lookup_commit_or_die(&merge_base,
1882                                                     options.onto_name);
1883         } else {
1884                 options.onto = peel_committish(options.onto_name);
1885                 if (!options.onto)
1886                         die(_("Does not point to a valid commit '%s'"),
1887                                 options.onto_name);
1888         }
1889
1890         /*
1891          * If the branch to rebase is given, that is the branch we will rebase
1892          * branch_name -- branch/commit being rebased, or
1893          *                HEAD (already detached)
1894          * orig_head -- commit object name of tip of the branch before rebasing
1895          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1896          */
1897         if (argc == 1) {
1898                 /* Is it "rebase other branchname" or "rebase other commit"? */
1899                 branch_name = argv[0];
1900                 options.switch_to = argv[0];
1901
1902                 /* Is it a local branch? */
1903                 strbuf_reset(&buf);
1904                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1905                 if (!read_ref(buf.buf, &options.orig_head)) {
1906                         die_if_checked_out(buf.buf, 1);
1907                         options.head_name = xstrdup(buf.buf);
1908                 /* If not is it a valid ref (branch or commit)? */
1909                 } else if (!get_oid(branch_name, &options.orig_head))
1910                         options.head_name = NULL;
1911                 else
1912                         die(_("fatal: no such branch/commit '%s'"),
1913                             branch_name);
1914         } else if (argc == 0) {
1915                 /* Do not need to switch branches, we are already on it. */
1916                 options.head_name =
1917                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1918                                          &flags));
1919                 if (!options.head_name)
1920                         die(_("No such ref: %s"), "HEAD");
1921                 if (flags & REF_ISSYMREF) {
1922                         if (!skip_prefix(options.head_name,
1923                                          "refs/heads/", &branch_name))
1924                                 branch_name = options.head_name;
1925
1926                 } else {
1927                         FREE_AND_NULL(options.head_name);
1928                         branch_name = "HEAD";
1929                 }
1930                 if (get_oid("HEAD", &options.orig_head))
1931                         die(_("Could not resolve HEAD to a revision"));
1932         } else
1933                 BUG("unexpected number of arguments left to parse");
1934
1935         if (fork_point > 0) {
1936                 struct commit *head =
1937                         lookup_commit_reference(the_repository,
1938                                                 &options.orig_head);
1939                 options.restrict_revision =
1940                         get_fork_point(options.upstream_name, head);
1941         }
1942
1943         if (repo_read_index(the_repository) < 0)
1944                 die(_("could not read index"));
1945
1946         if (options.autostash) {
1947                 create_autostash(the_repository, state_dir_path("autostash", &options),
1948                                  DEFAULT_REFLOG_ACTION);
1949         }
1950
1951         if (require_clean_work_tree(the_repository, "rebase",
1952                                     _("Please commit or stash them."), 1, 1)) {
1953                 ret = 1;
1954                 goto cleanup;
1955         }
1956
1957         /*
1958          * Now we are rebasing commits upstream..orig_head (or with --root,
1959          * everything leading up to orig_head) on top of onto.
1960          */
1961
1962         /*
1963          * Check if we are already based on onto with linear history,
1964          * in which case we could fast-forward without replacing the commits
1965          * with new commits recreated by replaying their changes.
1966          *
1967          * Note that can_fast_forward() initializes merge_base, so we have to
1968          * call it before checking allow_preemptive_ff.
1969          */
1970         if (can_fast_forward(options.onto, options.upstream, options.restrict_revision,
1971                     &options.orig_head, &merge_base) &&
1972             allow_preemptive_ff) {
1973                 int flag;
1974
1975                 if (!(options.flags & REBASE_FORCE)) {
1976                         /* Lazily switch to the target branch if needed... */
1977                         if (options.switch_to) {
1978                                 strbuf_reset(&buf);
1979                                 strbuf_addf(&buf, "%s: checkout %s",
1980                                             getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
1981                                             options.switch_to);
1982                                 if (reset_head(the_repository,
1983                                                &options.orig_head, "checkout",
1984                                                options.head_name,
1985                                                RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
1986                                                NULL, buf.buf,
1987                                                DEFAULT_REFLOG_ACTION) < 0) {
1988                                         ret = !!error(_("could not switch to "
1989                                                         "%s"),
1990                                                       options.switch_to);
1991                                         goto cleanup;
1992                                 }
1993                         }
1994
1995                         if (!(options.flags & REBASE_NO_QUIET))
1996                                 ; /* be quiet */
1997                         else if (!strcmp(branch_name, "HEAD") &&
1998                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
1999                                 puts(_("HEAD is up to date."));
2000                         else
2001                                 printf(_("Current branch %s is up to date.\n"),
2002                                        branch_name);
2003                         ret = !!finish_rebase(&options);
2004                         goto cleanup;
2005                 } else if (!(options.flags & REBASE_NO_QUIET))
2006                         ; /* be quiet */
2007                 else if (!strcmp(branch_name, "HEAD") &&
2008                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
2009                         puts(_("HEAD is up to date, rebase forced."));
2010                 else
2011                         printf(_("Current branch %s is up to date, rebase "
2012                                  "forced.\n"), branch_name);
2013         }
2014
2015         /* If a hook exists, give it a chance to interrupt*/
2016         if (!ok_to_skip_pre_rebase &&
2017             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
2018                         argc ? argv[0] : NULL, NULL))
2019                 die(_("The pre-rebase hook refused to rebase."));
2020
2021         if (options.flags & REBASE_DIFFSTAT) {
2022                 struct diff_options opts;
2023
2024                 if (options.flags & REBASE_VERBOSE) {
2025                         if (is_null_oid(&merge_base))
2026                                 printf(_("Changes to %s:\n"),
2027                                        oid_to_hex(&options.onto->object.oid));
2028                         else
2029                                 printf(_("Changes from %s to %s:\n"),
2030                                        oid_to_hex(&merge_base),
2031                                        oid_to_hex(&options.onto->object.oid));
2032                 }
2033
2034                 /* We want color (if set), but no pager */
2035                 diff_setup(&opts);
2036                 opts.stat_width = -1; /* use full terminal width */
2037                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
2038                 opts.output_format |=
2039                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
2040                 opts.detect_rename = DIFF_DETECT_RENAME;
2041                 diff_setup_done(&opts);
2042                 diff_tree_oid(is_null_oid(&merge_base) ?
2043                               the_hash_algo->empty_tree : &merge_base,
2044                               &options.onto->object.oid, "", &opts);
2045                 diffcore_std(&opts);
2046                 diff_flush(&opts);
2047         }
2048
2049         if (is_merge(&options))
2050                 goto run_rebase;
2051
2052         /* Detach HEAD and reset the tree */
2053         if (options.flags & REBASE_NO_QUIET)
2054                 printf(_("First, rewinding head to replay your work on top of "
2055                          "it...\n"));
2056
2057         strbuf_addf(&msg, "%s: checkout %s",
2058                     getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
2059         if (reset_head(the_repository, &options.onto->object.oid, "checkout", NULL,
2060                        RESET_HEAD_DETACH | RESET_ORIG_HEAD |
2061                        RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
2062                        NULL, msg.buf, DEFAULT_REFLOG_ACTION))
2063                 die(_("Could not detach HEAD"));
2064         strbuf_release(&msg);
2065
2066         /*
2067          * If the onto is a proper descendant of the tip of the branch, then
2068          * we just fast-forwarded.
2069          */
2070         strbuf_reset(&msg);
2071         if (oideq(&merge_base, &options.orig_head)) {
2072                 printf(_("Fast-forwarded %s to %s.\n"),
2073                         branch_name, options.onto_name);
2074                 strbuf_addf(&msg, "rebase finished: %s onto %s",
2075                         options.head_name ? options.head_name : "detached HEAD",
2076                         oid_to_hex(&options.onto->object.oid));
2077                 reset_head(the_repository, NULL, "Fast-forwarded", options.head_name,
2078                            RESET_HEAD_REFS_ONLY, "HEAD", msg.buf,
2079                            DEFAULT_REFLOG_ACTION);
2080                 strbuf_release(&msg);
2081                 ret = !!finish_rebase(&options);
2082                 goto cleanup;
2083         }
2084
2085         strbuf_addf(&revisions, "%s..%s",
2086                     options.root ? oid_to_hex(&options.onto->object.oid) :
2087                     (options.restrict_revision ?
2088                      oid_to_hex(&options.restrict_revision->object.oid) :
2089                      oid_to_hex(&options.upstream->object.oid)),
2090                     oid_to_hex(&options.orig_head));
2091
2092         options.revisions = revisions.buf;
2093
2094 run_rebase:
2095         ret = !!run_specific_rebase(&options, action);
2096
2097 cleanup:
2098         strbuf_release(&buf);
2099         strbuf_release(&revisions);
2100         free(options.head_name);
2101         free(options.gpg_sign_opt);
2102         free(options.cmd);
2103         free(squash_onto_name);
2104         return ret;
2105 }