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