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