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

   1 /*
   2  * "git rebase" builtin command
   3  *
   4  * Copyright (c) 2018 Pratik Karki
   5  */
   6
   7 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   8 #include "builtin.h"
   9 #include "run-command.h"
  10 #include "exec-cmd.h"
  11 #include "strvec.h"
  12 #include "dir.h"
  13 #include "packfile.h"
  14 #include "refs.h"
  15 #include "quote.h"
  16 #include "config.h"
  17 #include "cache-tree.h"
  18 #include "unpack-trees.h"
  19 #include "lockfile.h"
  20 #include "parse-options.h"
  21 #include "commit.h"
  22 #include "diff.h"
  23 #include "wt-status.h"
  24 #include "revision.h"
  25 #include "commit-reach.h"
  26 #include "rerere.h"
  27 #include "branch.h"
  28 #include "sequencer.h"
  29 #include "rebase-interactive.h"
  30 #include "reset.h"
  31
  32 #define DEFAULT_REFLOG_ACTION "rebase"
  33
  34 static char const * const builtin_rebase_usage[] = {
  35         N_("git rebase [-i] [options] [--exec <cmd>] "
  36                 "[--onto <newbase> | --keep-base] [<upstream> [<branch>]]"),
  37         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  38                 "--root [<branch>]"),
  39         N_("git rebase --continue | --abort | --skip | --edit-todo"),
  40         NULL
  41 };
  42
  43 static GIT_PATH_FUNC(path_squash_onto, "rebase-merge/squash-onto")
  44 static GIT_PATH_FUNC(path_interactive, "rebase-merge/interactive")
  45 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  46 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  47
  48 enum rebase_type {
  49         REBASE_UNSPECIFIED = -1,
  50         REBASE_APPLY,
  51         REBASE_MERGE,
  52         REBASE_PRESERVE_MERGES
  53 };
  54
  55 enum empty_type {
  56         EMPTY_UNSPECIFIED = -1,
  57         EMPTY_DROP,
  58         EMPTY_KEEP,
  59         EMPTY_ASK
  60 };
  61
  62 struct rebase_options {
  63         enum rebase_type type;
  64         enum empty_type empty;
  65         const char *default_backend;
  66         const char *state_dir;
  67         struct commit *upstream;
  68         const char *upstream_name;
  69         const char *upstream_arg;
  70         char *head_name;
  71         struct object_id orig_head;
  72         struct commit *onto;
  73         const char *onto_name;
  74         const char *revisions;
  75         const char *switch_to;
  76         int root, root_with_onto;
  77         struct object_id *squash_onto;
  78         struct commit *restrict_revision;
  79         int dont_finish_rebase;
  80         enum {
  81                 REBASE_NO_QUIET = 1<<0,
  82                 REBASE_VERBOSE = 1<<1,
  83                 REBASE_DIFFSTAT = 1<<2,
  84                 REBASE_FORCE = 1<<3,
  85                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  86         } flags;
  87         struct strvec git_am_opts;
  88         const char *action;
  89         int signoff;
  90         int allow_rerere_autoupdate;
  91         int keep_empty;
  92         int autosquash;
  93         char *gpg_sign_opt;
  94         int autostash;
  95         int committer_date_is_author_date;
  96         int ignore_date;
  97         char *cmd;
  98         int allow_empty_message;
  99         int rebase_merges, rebase_cousins;
 100         char *strategy, *strategy_opts;
 101         struct strbuf git_format_patch_opt;
 102         int reschedule_failed_exec;
 103         int reapply_cherry_picks;
 104         int fork_point;
 105 };
 106
 107 #define REBASE_OPTIONS_INIT {                           \
 108                 .type = REBASE_UNSPECIFIED,             \
 109                 .empty = EMPTY_UNSPECIFIED,             \
 110                 .keep_empty = 1,                        \
 111                 .default_backend = "merge",             \
 112                 .flags = REBASE_NO_QUIET,               \
 113                 .git_am_opts = STRVEC_INIT,             \
 114                 .git_format_patch_opt = STRBUF_INIT,    \
 115                 .fork_point = -1,                       \
 116         }
 117
 118 static struct replay_opts get_replay_opts(const struct rebase_options *opts)
 119 {
 120         struct replay_opts replay = REPLAY_OPTS_INIT;
 121
 122         replay.action = REPLAY_INTERACTIVE_REBASE;
 123         replay.strategy = NULL;
 124         sequencer_init_config(&replay);
 125
 126         replay.signoff = opts->signoff;
 127         replay.allow_ff = !(opts->flags & REBASE_FORCE);
 128         if (opts->allow_rerere_autoupdate)
 129                 replay.allow_rerere_auto = opts->allow_rerere_autoupdate;
 130         replay.allow_empty = 1;
 131         replay.allow_empty_message = opts->allow_empty_message;
 132         replay.drop_redundant_commits = (opts->empty == EMPTY_DROP);
 133         replay.keep_redundant_commits = (opts->empty == EMPTY_KEEP);
 134         replay.quiet = !(opts->flags & REBASE_NO_QUIET);
 135         replay.verbose = opts->flags & REBASE_VERBOSE;
 136         replay.reschedule_failed_exec = opts->reschedule_failed_exec;
 137         replay.committer_date_is_author_date =
 138                                         opts->committer_date_is_author_date;
 139         replay.ignore_date = opts->ignore_date;
 140         replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
 141         if (opts->strategy)
 142                 replay.strategy = opts->strategy;
 143         else if (!replay.strategy && replay.default_strategy) {
 144                 replay.strategy = replay.default_strategy;
 145                 replay.default_strategy = NULL;
 146         }
 147
 148         if (opts->strategy_opts)
 149                 parse_strategy_opts(&replay, opts->strategy_opts);
 150
 151         if (opts->squash_onto) {
 152                 oidcpy(&replay.squash_onto, opts->squash_onto);
 153                 replay.have_squash_onto = 1;
 154         }
 155
 156         return replay;
 157 }
 158
 159 enum action {
 160         ACTION_NONE = 0,
 161         ACTION_CONTINUE,
 162         ACTION_SKIP,
 163         ACTION_ABORT,
 164         ACTION_QUIT,
 165         ACTION_EDIT_TODO,
 166         ACTION_SHOW_CURRENT_PATCH,
 167         ACTION_SHORTEN_OIDS,
 168         ACTION_EXPAND_OIDS,
 169         ACTION_CHECK_TODO_LIST,
 170         ACTION_REARRANGE_SQUASH,
 171         ACTION_ADD_EXEC
 172 };
 173
 174 static const char *action_names[] = { "undefined",
 175                                       "continue",
 176                                       "skip",
 177                                       "abort",
 178                                       "quit",
 179                                       "edit_todo",
 180                                       "show_current_patch" };
 181
 182 static int add_exec_commands(struct string_list *commands)
 183 {
 184         const char *todo_file = rebase_path_todo();
 185         struct todo_list todo_list = TODO_LIST_INIT;
 186         int res;
 187
 188         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 189                 return error_errno(_("could not read '%s'."), todo_file);
 190
 191         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 192                                         &todo_list)) {
 193                 todo_list_release(&todo_list);
 194                 return error(_("unusable todo list: '%s'"), todo_file);
 195         }
 196
 197         todo_list_add_exec_commands(&todo_list, commands);
 198         res = todo_list_write_to_file(the_repository, &todo_list,
 199                                       todo_file, NULL, NULL, -1, 0);
 200         todo_list_release(&todo_list);
 201
 202         if (res)
 203                 return error_errno(_("could not write '%s'."), todo_file);
 204         return 0;
 205 }
 206
 207 static int rearrange_squash_in_todo_file(void)
 208 {
 209         const char *todo_file = rebase_path_todo();
 210         struct todo_list todo_list = TODO_LIST_INIT;
 211         int res = 0;
 212
 213         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 214                 return error_errno(_("could not read '%s'."), todo_file);
 215         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 216                                         &todo_list)) {
 217                 todo_list_release(&todo_list);
 218                 return error(_("unusable todo list: '%s'"), todo_file);
 219         }
 220
 221         res = todo_list_rearrange_squash(&todo_list);
 222         if (!res)
 223                 res = todo_list_write_to_file(the_repository, &todo_list,
 224                                               todo_file, NULL, NULL, -1, 0);
 225
 226         todo_list_release(&todo_list);
 227
 228         if (res)
 229                 return error_errno(_("could not write '%s'."), todo_file);
 230         return 0;
 231 }
 232
 233 static int transform_todo_file(unsigned flags)
 234 {
 235         const char *todo_file = rebase_path_todo();
 236         struct todo_list todo_list = TODO_LIST_INIT;
 237         int res;
 238
 239         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 240                 return error_errno(_("could not read '%s'."), todo_file);
 241
 242         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 243                                         &todo_list)) {
 244                 todo_list_release(&todo_list);
 245                 return error(_("unusable todo list: '%s'"), todo_file);
 246         }
 247
 248         res = todo_list_write_to_file(the_repository, &todo_list, todo_file,
 249                                       NULL, NULL, -1, flags);
 250         todo_list_release(&todo_list);
 251
 252         if (res)
 253                 return error_errno(_("could not write '%s'."), todo_file);
 254         return 0;
 255 }
 256
 257 static int edit_todo_file(unsigned flags)
 258 {
 259         const char *todo_file = rebase_path_todo();
 260         struct todo_list todo_list = TODO_LIST_INIT,
 261                 new_todo = TODO_LIST_INIT;
 262         int res = 0;
 263
 264         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 265                 return error_errno(_("could not read '%s'."), todo_file);
 266
 267         strbuf_stripspace(&todo_list.buf, 1);
 268         res = edit_todo_list(the_repository, &todo_list, &new_todo, NULL, NULL, flags);
 269         if (!res && todo_list_write_to_file(the_repository, &new_todo, todo_file,
 270                                             NULL, NULL, -1, flags & ~(TODO_LIST_SHORTEN_IDS)))
 271                 res = error_errno(_("could not write '%s'"), todo_file);
 272
 273         todo_list_release(&todo_list);
 274         todo_list_release(&new_todo);
 275
 276         return res;
 277 }
 278
 279 static int get_revision_ranges(struct commit *upstream, struct commit *onto,
 280                                struct object_id *orig_head, char **revisions,
 281                                char **shortrevisions)
 282 {
 283         struct commit *base_rev = upstream ? upstream : onto;
 284         const char *shorthead;
 285
 286         *revisions = xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oid),
 287                              oid_to_hex(orig_head));
 288
 289         shorthead = find_unique_abbrev(orig_head, DEFAULT_ABBREV);
 290
 291         if (upstream) {
 292                 const char *shortrev;
 293
 294                 shortrev = find_unique_abbrev(&base_rev->object.oid,
 295                                               DEFAULT_ABBREV);
 296
 297                 *shortrevisions = xstrfmt("%s..%s", shortrev, shorthead);
 298         } else
 299                 *shortrevisions = xstrdup(shorthead);
 300
 301         return 0;
 302 }
 303
 304 static int init_basic_state(struct replay_opts *opts, const char *head_name,
 305                             struct commit *onto,
 306                             const struct object_id *orig_head)
 307 {
 308         FILE *interactive;
 309
 310         if (!is_directory(merge_dir()) && mkdir_in_gitdir(merge_dir()))
 311                 return error_errno(_("could not create temporary %s"), merge_dir());
 312
 313         delete_reflog("REBASE_HEAD");
 314
 315         interactive = fopen(path_interactive(), "w");
 316         if (!interactive)
 317                 return error_errno(_("could not mark as interactive"));
 318         fclose(interactive);
 319
 320         return write_basic_state(opts, head_name, onto, orig_head);
 321 }
 322
 323 static void split_exec_commands(const char *cmd, struct string_list *commands)
 324 {
 325         if (cmd && *cmd) {
 326                 string_list_split(commands, cmd, '\n', -1);
 327
 328                 /* rebase.c adds a new line to cmd after every command,
 329                  * so here the last command is always empty */
 330                 string_list_remove_empty_items(commands, 0);
 331         }
 332 }
 333
 334 static int do_interactive_rebase(struct rebase_options *opts, unsigned flags)
 335 {
 336         int ret;
 337         char *revisions = NULL, *shortrevisions = NULL;
 338         struct strvec make_script_args = STRVEC_INIT;
 339         struct todo_list todo_list = TODO_LIST_INIT;
 340         struct replay_opts replay = get_replay_opts(opts);
 341         struct string_list commands = STRING_LIST_INIT_DUP;
 342
 343         if (get_revision_ranges(opts->upstream, opts->onto, &opts->orig_head,
 344                                 &revisions, &shortrevisions))
 345                 return -1;
 346
 347         if (init_basic_state(&replay,
 348                              opts->head_name ? opts->head_name : "detached HEAD",
 349                              opts->onto, &opts->orig_head)) {
 350                 free(revisions);
 351                 free(shortrevisions);
 352
 353                 return -1;
 354         }
 355
 356         if (!opts->upstream && opts->squash_onto)
 357                 write_file(path_squash_onto(), "%s\n",
 358                            oid_to_hex(opts->squash_onto));
 359
 360         strvec_pushl(&make_script_args, "", revisions, NULL);
 361         if (opts->restrict_revision)
 362                 strvec_pushf(&make_script_args, "^%s",
 363                              oid_to_hex(&opts->restrict_revision->object.oid));
 364
 365         ret = sequencer_make_script(the_repository, &todo_list.buf,
 366                                     make_script_args.nr, make_script_args.v,
 367                                     flags);
 368
 369         if (ret)
 370                 error(_("could not generate todo list"));
 371         else {
 372                 discard_cache();
 373                 if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
 374                                                 &todo_list))
 375                         BUG("unusable todo list");
 376
 377                 split_exec_commands(opts->cmd, &commands);
 378                 ret = complete_action(the_repository, &replay, flags,
 379                         shortrevisions, opts->onto_name, opts->onto,
 380                         &opts->orig_head, &commands, opts->autosquash,
 381                         &todo_list);
 382         }
 383
 384         string_list_clear(&commands, 0);
 385         free(revisions);
 386         free(shortrevisions);
 387         todo_list_release(&todo_list);
 388         strvec_clear(&make_script_args);
 389
 390         return ret;
 391 }
 392
 393 static int run_sequencer_rebase(struct rebase_options *opts,
 394                                   enum action command)
 395 {
 396         unsigned flags = 0;
 397         int abbreviate_commands = 0, ret = 0;
 398
 399         git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
 400
 401         flags |= opts->keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
 402         flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
 403         flags |= opts->rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
 404         flags |= opts->rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
 405         flags |= opts->root_with_onto ? TODO_LIST_ROOT_WITH_ONTO : 0;
 406         flags |= command == ACTION_SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
 407         flags |= opts->reapply_cherry_picks ? TODO_LIST_REAPPLY_CHERRY_PICKS : 0;
 408
 409         switch (command) {
 410         case ACTION_NONE: {
 411                 if (!opts->onto && !opts->upstream)
 412                         die(_("a base commit must be provided with --upstream or --onto"));
 413
 414                 ret = do_interactive_rebase(opts, flags);
 415                 break;
 416         }
 417         case ACTION_SKIP: {
 418                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
 419
 420                 rerere_clear(the_repository, &merge_rr);
 421         }
 422                 /* fallthrough */
 423         case ACTION_CONTINUE: {
 424                 struct replay_opts replay_opts = get_replay_opts(opts);
 425
 426                 ret = sequencer_continue(the_repository, &replay_opts);
 427                 break;
 428         }
 429         case ACTION_EDIT_TODO:
 430                 ret = edit_todo_file(flags);
 431                 break;
 432         case ACTION_SHOW_CURRENT_PATCH: {
 433                 struct child_process cmd = CHILD_PROCESS_INIT;
 434
 435                 cmd.git_cmd = 1;
 436                 strvec_pushl(&cmd.args, "show", "REBASE_HEAD", "--", NULL);
 437                 ret = run_command(&cmd);
 438
 439                 break;
 440         }
 441         case ACTION_SHORTEN_OIDS:
 442         case ACTION_EXPAND_OIDS:
 443                 ret = transform_todo_file(flags);
 444                 break;
 445         case ACTION_CHECK_TODO_LIST:
 446                 ret = check_todo_list_from_file(the_repository);
 447                 break;
 448         case ACTION_REARRANGE_SQUASH:
 449                 ret = rearrange_squash_in_todo_file();
 450                 break;
 451         case ACTION_ADD_EXEC: {
 452                 struct string_list commands = STRING_LIST_INIT_DUP;
 453
 454                 split_exec_commands(opts->cmd, &commands);
 455                 ret = add_exec_commands(&commands);
 456                 string_list_clear(&commands, 0);
 457                 break;
 458         }
 459         default:
 460                 BUG("invalid command '%d'", command);
 461         }
 462
 463         return ret;
 464 }
 465
 466 static void imply_merge(struct rebase_options *opts, const char *option);
 467 static int parse_opt_keep_empty(const struct option *opt, const char *arg,
 468                                 int unset)
 469 {
 470         struct rebase_options *opts = opt->value;
 471
 472         BUG_ON_OPT_ARG(arg);
 473
 474         imply_merge(opts, unset ? "--no-keep-empty" : "--keep-empty");
 475         opts->keep_empty = !unset;
 476         opts->type = REBASE_MERGE;
 477         return 0;
 478 }
 479
 480 static const char * const builtin_rebase_interactive_usage[] = {
 481         N_("git rebase--interactive [<options>]"),
 482         NULL
 483 };
 484
 485 int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 486 {
 487         struct rebase_options opts = REBASE_OPTIONS_INIT;
 488         struct object_id squash_onto = *null_oid();
 489         enum action command = ACTION_NONE;
 490         struct option options[] = {
 491                 OPT_NEGBIT(0, "ff", &opts.flags, N_("allow fast-forward"),
 492                            REBASE_FORCE),
 493                 OPT_CALLBACK_F('k', "keep-empty", &options, NULL,
 494                         N_("keep commits which start empty"),
 495                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
 496                         parse_opt_keep_empty),
 497                 OPT_BOOL_F(0, "allow-empty-message", &opts.allow_empty_message,
 498                            N_("allow commits with empty messages"),
 499                            PARSE_OPT_HIDDEN),
 500                 OPT_BOOL(0, "rebase-merges", &opts.rebase_merges, N_("rebase merge commits")),
 501                 OPT_BOOL(0, "rebase-cousins", &opts.rebase_cousins,
 502                          N_("keep original branch points of cousins")),
 503                 OPT_BOOL(0, "autosquash", &opts.autosquash,
 504                          N_("move commits that begin with squash!/fixup!")),
 505                 OPT_BOOL(0, "signoff", &opts.signoff, N_("sign commits")),
 506                 OPT_BIT('v', "verbose", &opts.flags,
 507                         N_("display a diffstat of what changed upstream"),
 508                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 509                 OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
 510                             ACTION_CONTINUE),
 511                 OPT_CMDMODE(0, "skip", &command, N_("skip commit"), ACTION_SKIP),
 512                 OPT_CMDMODE(0, "edit-todo", &command, N_("edit the todo list"),
 513                             ACTION_EDIT_TODO),
 514                 OPT_CMDMODE(0, "show-current-patch", &command, N_("show the current patch"),
 515                             ACTION_SHOW_CURRENT_PATCH),
 516                 OPT_CMDMODE(0, "shorten-ids", &command,
 517                         N_("shorten commit ids in the todo list"), ACTION_SHORTEN_OIDS),
 518                 OPT_CMDMODE(0, "expand-ids", &command,
 519                         N_("expand commit ids in the todo list"), ACTION_EXPAND_OIDS),
 520                 OPT_CMDMODE(0, "check-todo-list", &command,
 521                         N_("check the todo list"), ACTION_CHECK_TODO_LIST),
 522                 OPT_CMDMODE(0, "rearrange-squash", &command,
 523                         N_("rearrange fixup/squash lines"), ACTION_REARRANGE_SQUASH),
 524                 OPT_CMDMODE(0, "add-exec-commands", &command,
 525                         N_("insert exec commands in todo list"), ACTION_ADD_EXEC),
 526                 { OPTION_CALLBACK, 0, "onto", &opts.onto, N_("onto"), N_("onto"),
 527                   PARSE_OPT_NONEG, parse_opt_commit, 0 },
 528                 { OPTION_CALLBACK, 0, "restrict-revision", &opts.restrict_revision,
 529                   N_("restrict-revision"), N_("restrict revision"),
 530                   PARSE_OPT_NONEG, parse_opt_commit, 0 },
 531                 { OPTION_CALLBACK, 0, "squash-onto", &squash_onto, N_("squash-onto"),
 532                   N_("squash onto"), PARSE_OPT_NONEG, parse_opt_object_id, 0 },
 533                 { OPTION_CALLBACK, 0, "upstream", &opts.upstream, N_("upstream"),
 534                   N_("the upstream commit"), PARSE_OPT_NONEG, parse_opt_commit,
 535                   0 },
 536                 OPT_STRING(0, "head-name", &opts.head_name, N_("head-name"), N_("head name")),
 537                 { OPTION_STRING, 'S', "gpg-sign", &opts.gpg_sign_opt, N_("key-id"),
 538                         N_("GPG-sign commits"),
 539                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 540                 OPT_STRING(0, "strategy", &opts.strategy, N_("strategy"),
 541                            N_("rebase strategy")),
 542                 OPT_STRING(0, "strategy-opts", &opts.strategy_opts, N_("strategy-opts"),
 543                            N_("strategy options")),
 544                 OPT_STRING(0, "switch-to", &opts.switch_to, N_("switch-to"),
 545                            N_("the branch or commit to checkout")),
 546                 OPT_STRING(0, "onto-name", &opts.onto_name, N_("onto-name"), N_("onto name")),
 547                 OPT_STRING(0, "cmd", &opts.cmd, N_("cmd"), N_("the command to run")),
 548                 OPT_RERERE_AUTOUPDATE(&opts.allow_rerere_autoupdate),
 549                 OPT_BOOL(0, "reschedule-failed-exec", &opts.reschedule_failed_exec,
 550                          N_("automatically re-schedule any `exec` that fails")),
 551                 OPT_END()
 552         };
 553
 554         opts.rebase_cousins = -1;
 555
 556         if (argc == 1)
 557                 usage_with_options(builtin_rebase_interactive_usage, options);
 558
 559         argc = parse_options(argc, argv, prefix, options,
 560                         builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
 561
 562         if (!is_null_oid(&squash_onto))
 563                 opts.squash_onto = &squash_onto;
 564
 565         if (opts.rebase_cousins >= 0 && !opts.rebase_merges)
 566                 warning(_("--[no-]rebase-cousins has no effect without "
 567                           "--rebase-merges"));
 568
 569         return !!run_sequencer_rebase(&opts, command);
 570 }
 571
 572 static int is_merge(struct rebase_options *opts)
 573 {
 574         return opts->type == REBASE_MERGE ||
 575                 opts->type == REBASE_PRESERVE_MERGES;
 576 }
 577
 578 static void imply_merge(struct rebase_options *opts, const char *option)
 579 {
 580         switch (opts->type) {
 581         case REBASE_APPLY:
 582                 die(_("%s requires the merge backend"), option);
 583                 break;
 584         case REBASE_MERGE:
 585         case REBASE_PRESERVE_MERGES:
 586                 break;
 587         default:
 588                 opts->type = REBASE_MERGE; /* implied */
 589                 break;
 590         }
 591 }
 592
 593 /* Returns the filename prefixed by the state_dir */
 594 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 595 {
 596         static struct strbuf path = STRBUF_INIT;
 597         static size_t prefix_len;
 598
 599         if (!prefix_len) {
 600                 strbuf_addf(&path, "%s/", opts->state_dir);
 601                 prefix_len = path.len;
 602         }
 603
 604         strbuf_setlen(&path, prefix_len);
 605         strbuf_addstr(&path, filename);
 606         return path.buf;
 607 }
 608
 609 /* Initialize the rebase options from the state directory. */
 610 static int read_basic_state(struct rebase_options *opts)
 611 {
 612         struct strbuf head_name = STRBUF_INIT;
 613         struct strbuf buf = STRBUF_INIT;
 614         struct object_id oid;
 615
 616         if (!read_oneliner(&head_name, state_dir_path("head-name", opts),
 617                            READ_ONELINER_WARN_MISSING) ||
 618             !read_oneliner(&buf, state_dir_path("onto", opts),
 619                            READ_ONELINER_WARN_MISSING))
 620                 return -1;
 621         opts->head_name = starts_with(head_name.buf, "refs/") ?
 622                 xstrdup(head_name.buf) : NULL;
 623         strbuf_release(&head_name);
 624         if (get_oid(buf.buf, &oid))
 625                 return error(_("could not get 'onto': '%s'"), buf.buf);
 626         opts->onto = lookup_commit_or_die(&oid, buf.buf);
 627
 628         /*
 629          * We always write to orig-head, but interactive rebase used to write to
 630          * head. Fall back to reading from head to cover for the case that the
 631          * user upgraded git with an ongoing interactive rebase.
 632          */
 633         strbuf_reset(&buf);
 634         if (file_exists(state_dir_path("orig-head", opts))) {
 635                 if (!read_oneliner(&buf, state_dir_path("orig-head", opts),
 636                                    READ_ONELINER_WARN_MISSING))
 637                         return -1;
 638         } else if (!read_oneliner(&buf, state_dir_path("head", opts),
 639                                   READ_ONELINER_WARN_MISSING))
 640                 return -1;
 641         if (get_oid(buf.buf, &opts->orig_head))
 642                 return error(_("invalid orig-head: '%s'"), buf.buf);
 643
 644         if (file_exists(state_dir_path("quiet", opts)))
 645                 opts->flags &= ~REBASE_NO_QUIET;
 646         else
 647                 opts->flags |= REBASE_NO_QUIET;
 648
 649         if (file_exists(state_dir_path("verbose", opts)))
 650                 opts->flags |= REBASE_VERBOSE;
 651
 652         if (file_exists(state_dir_path("signoff", opts))) {
 653                 opts->signoff = 1;
 654                 opts->flags |= REBASE_FORCE;
 655         }
 656
 657         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
 658                 strbuf_reset(&buf);
 659                 if (!read_oneliner(&buf, state_dir_path("allow_rerere_autoupdate", opts),
 660                                    READ_ONELINER_WARN_MISSING))
 661                         return -1;
 662                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
 663                         opts->allow_rerere_autoupdate = RERERE_AUTOUPDATE;
 664                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
 665                         opts->allow_rerere_autoupdate = RERERE_NOAUTOUPDATE;
 666                 else
 667                         warning(_("ignoring invalid allow_rerere_autoupdate: "
 668                                   "'%s'"), buf.buf);
 669         }
 670
 671         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
 672                 strbuf_reset(&buf);
 673                 if (!read_oneliner(&buf, state_dir_path("gpg_sign_opt", opts),
 674                                    READ_ONELINER_WARN_MISSING))
 675                         return -1;
 676                 free(opts->gpg_sign_opt);
 677                 opts->gpg_sign_opt = xstrdup(buf.buf);
 678         }
 679
 680         if (file_exists(state_dir_path("strategy", opts))) {
 681                 strbuf_reset(&buf);
 682                 if (!read_oneliner(&buf, state_dir_path("strategy", opts),
 683                                    READ_ONELINER_WARN_MISSING))
 684                         return -1;
 685                 free(opts->strategy);
 686                 opts->strategy = xstrdup(buf.buf);
 687         }
 688
 689         if (file_exists(state_dir_path("strategy_opts", opts))) {
 690                 strbuf_reset(&buf);
 691                 if (!read_oneliner(&buf, state_dir_path("strategy_opts", opts),
 692                                    READ_ONELINER_WARN_MISSING))
 693                         return -1;
 694                 free(opts->strategy_opts);
 695                 opts->strategy_opts = xstrdup(buf.buf);
 696         }
 697
 698         strbuf_release(&buf);
 699
 700         return 0;
 701 }
 702
 703 static int rebase_write_basic_state(struct rebase_options *opts)
 704 {
 705         write_file(state_dir_path("head-name", opts), "%s",
 706                    opts->head_name ? opts->head_name : "detached HEAD");
 707         write_file(state_dir_path("onto", opts), "%s",
 708                    opts->onto ? oid_to_hex(&opts->onto->object.oid) : "");
 709         write_file(state_dir_path("orig-head", opts), "%s",
 710                    oid_to_hex(&opts->orig_head));
 711         if (!(opts->flags & REBASE_NO_QUIET))
 712                 write_file(state_dir_path("quiet", opts), "%s", "");
 713         if (opts->flags & REBASE_VERBOSE)
 714                 write_file(state_dir_path("verbose", opts), "%s", "");
 715         if (opts->strategy)
 716                 write_file(state_dir_path("strategy", opts), "%s",
 717                            opts->strategy);
 718         if (opts->strategy_opts)
 719                 write_file(state_dir_path("strategy_opts", opts), "%s",
 720                            opts->strategy_opts);
 721         if (opts->allow_rerere_autoupdate > 0)
 722                 write_file(state_dir_path("allow_rerere_autoupdate", opts),
 723                            "-%s-rerere-autoupdate",
 724                            opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
 725                                 "" : "-no");
 726         if (opts->gpg_sign_opt)
 727                 write_file(state_dir_path("gpg_sign_opt", opts), "%s",
 728                            opts->gpg_sign_opt);
 729         if (opts->signoff)
 730                 write_file(state_dir_path("signoff", opts), "--signoff");
 731
 732         return 0;
 733 }
 734
 735 static int finish_rebase(struct rebase_options *opts)
 736 {
 737         struct strbuf dir = STRBUF_INIT;
 738         int ret = 0;
 739
 740         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 741         unlink(git_path_auto_merge(the_repository));
 742         apply_autostash(state_dir_path("autostash", opts));
 743         close_object_store(the_repository->objects);
 744         /*
 745          * We ignore errors in 'git maintenance run --auto', since the
 746          * user should see them.
 747          */
 748         run_auto_maintenance(!(opts->flags & (REBASE_NO_QUIET|REBASE_VERBOSE)));
 749         if (opts->type == REBASE_MERGE) {
 750                 struct replay_opts replay = REPLAY_OPTS_INIT;
 751
 752                 replay.action = REPLAY_INTERACTIVE_REBASE;
 753                 ret = sequencer_remove_state(&replay);
 754         } else {
 755                 strbuf_addstr(&dir, opts->state_dir);
 756                 if (remove_dir_recursively(&dir, 0))
 757                         ret = error(_("could not remove '%s'"),
 758                                     opts->state_dir);
 759                 strbuf_release(&dir);
 760         }
 761
 762         return ret;
 763 }
 764
 765 static struct commit *peel_committish(const char *name)
 766 {
 767         struct object *obj;
 768         struct object_id oid;
 769
 770         if (get_oid(name, &oid))
 771                 return NULL;
 772         obj = parse_object(the_repository, &oid);
 773         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 774 }
 775
 776 static void add_var(struct strbuf *buf, const char *name, const char *value)
 777 {
 778         if (!value)
 779                 strbuf_addf(buf, "unset %s; ", name);
 780         else {
 781                 strbuf_addf(buf, "%s=", name);
 782                 sq_quote_buf(buf, value);
 783                 strbuf_addstr(buf, "; ");
 784         }
 785 }
 786
 787 static int move_to_original_branch(struct rebase_options *opts)
 788 {
 789         struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
 790         int ret;
 791
 792         if (!opts->head_name)
 793                 return 0; /* nothing to move back to */
 794
 795         if (!opts->onto)
 796                 BUG("move_to_original_branch without onto");
 797
 798         strbuf_addf(&orig_head_reflog, "rebase finished: %s onto %s",
 799                     opts->head_name, oid_to_hex(&opts->onto->object.oid));
 800         strbuf_addf(&head_reflog, "rebase finished: returning to %s",
 801                     opts->head_name);
 802         ret = reset_head(the_repository, NULL, "", opts->head_name,
 803                          RESET_HEAD_REFS_ONLY,
 804                          orig_head_reflog.buf, head_reflog.buf,
 805                          DEFAULT_REFLOG_ACTION);
 806
 807         strbuf_release(&orig_head_reflog);
 808         strbuf_release(&head_reflog);
 809         return ret;
 810 }
 811
 812 static const char *resolvemsg =
 813 N_("Resolve all conflicts manually, mark them as resolved with\n"
 814 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
 815 "You can instead skip this commit: run \"git rebase --skip\".\n"
 816 "To abort and get back to the state before \"git rebase\", run "
 817 "\"git rebase --abort\".");
 818
 819 static int run_am(struct rebase_options *opts)
 820 {
 821         struct child_process am = CHILD_PROCESS_INIT;
 822         struct child_process format_patch = CHILD_PROCESS_INIT;
 823         struct strbuf revisions = STRBUF_INIT;
 824         int status;
 825         char *rebased_patches;
 826
 827         am.git_cmd = 1;
 828         strvec_push(&am.args, "am");
 829
 830         if (opts->action && !strcmp("continue", opts->action)) {
 831                 strvec_push(&am.args, "--resolved");
 832                 strvec_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 833                 if (opts->gpg_sign_opt)
 834                         strvec_push(&am.args, opts->gpg_sign_opt);
 835                 status = run_command(&am);
 836                 if (status)
 837                         return status;
 838
 839                 return move_to_original_branch(opts);
 840         }
 841         if (opts->action && !strcmp("skip", opts->action)) {
 842                 strvec_push(&am.args, "--skip");
 843                 strvec_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 844                 status = run_command(&am);
 845                 if (status)
 846                         return status;
 847
 848                 return move_to_original_branch(opts);
 849         }
 850         if (opts->action && !strcmp("show-current-patch", opts->action)) {
 851                 strvec_push(&am.args, "--show-current-patch");
 852                 return run_command(&am);
 853         }
 854
 855         strbuf_addf(&revisions, "%s...%s",
 856                     oid_to_hex(opts->root ?
 857                                /* this is now equivalent to !opts->upstream */
 858                                &opts->onto->object.oid :
 859                                &opts->upstream->object.oid),
 860                     oid_to_hex(&opts->orig_head));
 861
 862         rebased_patches = xstrdup(git_path("rebased-patches"));
 863         format_patch.out = open(rebased_patches,
 864                                 O_WRONLY | O_CREAT | O_TRUNC, 0666);
 865         if (format_patch.out < 0) {
 866                 status = error_errno(_("could not open '%s' for writing"),
 867                                      rebased_patches);
 868                 free(rebased_patches);
 869                 strvec_clear(&am.args);
 870                 return status;
 871         }
 872
 873         format_patch.git_cmd = 1;
 874         strvec_pushl(&format_patch.args, "format-patch", "-k", "--stdout",
 875                      "--full-index", "--cherry-pick", "--right-only",
 876                      "--src-prefix=a/", "--dst-prefix=b/", "--no-renames",
 877                      "--no-cover-letter", "--pretty=mboxrd", "--topo-order",
 878                      "--no-base", NULL);
 879         if (opts->git_format_patch_opt.len)
 880                 strvec_split(&format_patch.args,
 881                              opts->git_format_patch_opt.buf);
 882         strvec_push(&format_patch.args, revisions.buf);
 883         if (opts->restrict_revision)
 884                 strvec_pushf(&format_patch.args, "^%s",
 885                              oid_to_hex(&opts->restrict_revision->object.oid));
 886
 887         status = run_command(&format_patch);
 888         if (status) {
 889                 unlink(rebased_patches);
 890                 free(rebased_patches);
 891                 strvec_clear(&am.args);
 892
 893                 reset_head(the_repository, &opts->orig_head, "checkout",
 894                            opts->head_name, 0,
 895                            "HEAD", NULL, DEFAULT_REFLOG_ACTION);
 896                 error(_("\ngit encountered an error while preparing the "
 897                         "patches to replay\n"
 898                         "these revisions:\n"
 899                         "\n    %s\n\n"
 900                         "As a result, git cannot rebase them."),
 901                       opts->revisions);
 902
 903                 strbuf_release(&revisions);
 904                 return status;
 905         }
 906         strbuf_release(&revisions);
 907
 908         am.in = open(rebased_patches, O_RDONLY);
 909         if (am.in < 0) {
 910                 status = error_errno(_("could not open '%s' for reading"),
 911                                      rebased_patches);
 912                 free(rebased_patches);
 913                 strvec_clear(&am.args);
 914                 return status;
 915         }
 916
 917         strvec_pushv(&am.args, opts->git_am_opts.v);
 918         strvec_push(&am.args, "--rebasing");
 919         strvec_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
 920         strvec_push(&am.args, "--patch-format=mboxrd");
 921         if (opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE)
 922                 strvec_push(&am.args, "--rerere-autoupdate");
 923         else if (opts->allow_rerere_autoupdate == RERERE_NOAUTOUPDATE)
 924                 strvec_push(&am.args, "--no-rerere-autoupdate");
 925         if (opts->gpg_sign_opt)
 926                 strvec_push(&am.args, opts->gpg_sign_opt);
 927         status = run_command(&am);
 928         unlink(rebased_patches);
 929         free(rebased_patches);
 930
 931         if (!status) {
 932                 return move_to_original_branch(opts);
 933         }
 934
 935         if (is_directory(opts->state_dir))
 936                 rebase_write_basic_state(opts);
 937
 938         return status;
 939 }
 940
 941 static int run_specific_rebase(struct rebase_options *opts, enum action action)
 942 {
 943         const char *argv[] = { NULL, NULL };
 944         struct strbuf script_snippet = STRBUF_INIT, buf = STRBUF_INIT;
 945         int status;
 946         const char *backend, *backend_func;
 947
 948         if (opts->type == REBASE_MERGE) {
 949                 /* Run sequencer-based rebase */
 950                 setenv("GIT_CHERRY_PICK_HELP", resolvemsg, 1);
 951                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 952                         setenv("GIT_SEQUENCE_EDITOR", ":", 1);
 953                         opts->autosquash = 0;
 954                 }
 955                 if (opts->gpg_sign_opt) {
 956                         /* remove the leading "-S" */
 957                         char *tmp = xstrdup(opts->gpg_sign_opt + 2);
 958                         free(opts->gpg_sign_opt);
 959                         opts->gpg_sign_opt = tmp;
 960                 }
 961
 962                 status = run_sequencer_rebase(opts, action);
 963                 goto finished_rebase;
 964         }
 965
 966         if (opts->type == REBASE_APPLY) {
 967                 status = run_am(opts);
 968                 goto finished_rebase;
 969         }
 970
 971         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 972         add_var(&script_snippet, "state_dir", opts->state_dir);
 973
 974         add_var(&script_snippet, "upstream_name", opts->upstream_name);
 975         add_var(&script_snippet, "upstream", opts->upstream ?
 976                 oid_to_hex(&opts->upstream->object.oid) : NULL);
 977         add_var(&script_snippet, "head_name",
 978                 opts->head_name ? opts->head_name : "detached HEAD");
 979         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 980         add_var(&script_snippet, "onto", opts->onto ?
 981                 oid_to_hex(&opts->onto->object.oid) : NULL);
 982         add_var(&script_snippet, "onto_name", opts->onto_name);
 983         add_var(&script_snippet, "revisions", opts->revisions);
 984         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 985                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 986         sq_quote_argv_pretty(&buf, opts->git_am_opts.v);
 987         add_var(&script_snippet, "git_am_opt", buf.buf);
 988         strbuf_release(&buf);
 989         add_var(&script_snippet, "verbose",
 990                 opts->flags & REBASE_VERBOSE ? "t" : "");
 991         add_var(&script_snippet, "diffstat",
 992                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
 993         add_var(&script_snippet, "force_rebase",
 994                 opts->flags & REBASE_FORCE ? "t" : "");
 995         if (opts->switch_to)
 996                 add_var(&script_snippet, "switch_to", opts->switch_to);
 997         add_var(&script_snippet, "action", opts->action ? opts->action : "");
 998         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
 999         add_var(&script_snippet, "allow_rerere_autoupdate",
1000                 opts->allow_rerere_autoupdate ?
1001                         opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
1002                         "--rerere-autoupdate" : "--no-rerere-autoupdate" : "");
1003         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
1004         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
1005         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
1006         add_var(&script_snippet, "cmd", opts->cmd);
1007         add_var(&script_snippet, "allow_empty_message",
1008                 opts->allow_empty_message ?  "--allow-empty-message" : "");
1009         add_var(&script_snippet, "rebase_merges",
1010                 opts->rebase_merges ? "t" : "");
1011         add_var(&script_snippet, "rebase_cousins",
1012                 opts->rebase_cousins ? "t" : "");
1013         add_var(&script_snippet, "strategy", opts->strategy);
1014         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
1015         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
1016         add_var(&script_snippet, "squash_onto",
1017                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
1018         add_var(&script_snippet, "git_format_patch_opt",
1019                 opts->git_format_patch_opt.buf);
1020
1021         if (is_merge(opts) &&
1022             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
1023                 strbuf_addstr(&script_snippet,
1024                               "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
1025                 opts->autosquash = 0;
1026         }
1027
1028         switch (opts->type) {
1029         case REBASE_PRESERVE_MERGES:
1030                 backend = "git-rebase--preserve-merges";
1031                 backend_func = "git_rebase__preserve_merges";
1032                 break;
1033         default:
1034                 BUG("Unhandled rebase type %d", opts->type);
1035                 break;
1036         }
1037
1038         strbuf_addf(&script_snippet,
1039                     ". git-sh-setup && . %s && %s", backend, backend_func);
1040         argv[0] = script_snippet.buf;
1041
1042         status = run_command_v_opt(argv, RUN_USING_SHELL);
1043 finished_rebase:
1044         if (opts->dont_finish_rebase)
1045                 ; /* do nothing */
1046         else if (opts->type == REBASE_MERGE)
1047                 ; /* merge backend cleans up after itself */
1048         else if (status == 0) {
1049                 if (!file_exists(state_dir_path("stopped-sha", opts)))
1050                         finish_rebase(opts);
1051         } else if (status == 2) {
1052                 struct strbuf dir = STRBUF_INIT;
1053
1054                 apply_autostash(state_dir_path("autostash", opts));
1055                 strbuf_addstr(&dir, opts->state_dir);
1056                 remove_dir_recursively(&dir, 0);
1057                 strbuf_release(&dir);
1058                 die("Nothing to do");
1059         }
1060
1061         strbuf_release(&script_snippet);
1062
1063         return status ? -1 : 0;
1064 }
1065
1066 static int rebase_config(const char *var, const char *value, void *data)
1067 {
1068         struct rebase_options *opts = data;
1069
1070         if (!strcmp(var, "rebase.stat")) {
1071                 if (git_config_bool(var, value))
1072                         opts->flags |= REBASE_DIFFSTAT;
1073                 else
1074                         opts->flags &= ~REBASE_DIFFSTAT;
1075                 return 0;
1076         }
1077
1078         if (!strcmp(var, "rebase.autosquash")) {
1079                 opts->autosquash = git_config_bool(var, value);
1080                 return 0;
1081         }
1082
1083         if (!strcmp(var, "commit.gpgsign")) {
1084                 free(opts->gpg_sign_opt);
1085                 opts->gpg_sign_opt = git_config_bool(var, value) ?
1086                         xstrdup("-S") : NULL;
1087                 return 0;
1088         }
1089
1090         if (!strcmp(var, "rebase.autostash")) {
1091                 opts->autostash = git_config_bool(var, value);
1092                 return 0;
1093         }
1094
1095         if (!strcmp(var, "rebase.reschedulefailedexec")) {
1096                 opts->reschedule_failed_exec = git_config_bool(var, value);
1097                 return 0;
1098         }
1099
1100         if (!strcmp(var, "rebase.forkpoint")) {
1101                 opts->fork_point = git_config_bool(var, value) ? -1 : 0;
1102                 return 0;
1103         }
1104
1105         if (!strcmp(var, "rebase.backend")) {
1106                 return git_config_string(&opts->default_backend, var, value);
1107         }
1108
1109         return git_default_config(var, value, data);
1110 }
1111
1112 /*
1113  * Determines whether the commits in from..to are linear, i.e. contain
1114  * no merge commits. This function *expects* `from` to be an ancestor of
1115  * `to`.
1116  */
1117 static int is_linear_history(struct commit *from, struct commit *to)
1118 {
1119         while (to && to != from) {
1120                 parse_commit(to);
1121                 if (!to->parents)
1122                         return 1;
1123                 if (to->parents->next)
1124                         return 0;
1125                 to = to->parents->item;
1126         }
1127         return 1;
1128 }
1129
1130 static int can_fast_forward(struct commit *onto, struct commit *upstream,
1131                             struct commit *restrict_revision,
1132                             struct object_id *head_oid, struct object_id *merge_base)
1133 {
1134         struct commit *head = lookup_commit(the_repository, head_oid);
1135         struct commit_list *merge_bases = NULL;
1136         int res = 0;
1137
1138         if (!head)
1139                 goto done;
1140
1141         merge_bases = get_merge_bases(onto, head);
1142         if (!merge_bases || merge_bases->next) {
1143                 oidcpy(merge_base, null_oid());
1144                 goto done;
1145         }
1146
1147         oidcpy(merge_base, &merge_bases->item->object.oid);
1148         if (!oideq(merge_base, &onto->object.oid))
1149                 goto done;
1150
1151         if (restrict_revision && !oideq(&restrict_revision->object.oid, merge_base))
1152                 goto done;
1153
1154         if (!upstream)
1155                 goto done;
1156
1157         free_commit_list(merge_bases);
1158         merge_bases = get_merge_bases(upstream, head);
1159         if (!merge_bases || merge_bases->next)
1160                 goto done;
1161
1162         if (!oideq(&onto->object.oid, &merge_bases->item->object.oid))
1163                 goto done;
1164
1165         res = 1;
1166
1167 done:
1168         free_commit_list(merge_bases);
1169         return res && is_linear_history(onto, head);
1170 }
1171
1172 static int parse_opt_am(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         opts->type = REBASE_APPLY;
1180
1181         return 0;
1182 }
1183
1184 /* -i followed by -m is still -i */
1185 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
1186 {
1187         struct rebase_options *opts = opt->value;
1188
1189         BUG_ON_OPT_NEG(unset);
1190         BUG_ON_OPT_ARG(arg);
1191
1192         if (!is_merge(opts))
1193                 opts->type = REBASE_MERGE;
1194
1195         return 0;
1196 }
1197
1198 /* -i followed by -p is still explicitly interactive, but -p alone is not */
1199 static int parse_opt_interactive(const struct option *opt, const char *arg,
1200                                  int unset)
1201 {
1202         struct rebase_options *opts = opt->value;
1203
1204         BUG_ON_OPT_NEG(unset);
1205         BUG_ON_OPT_ARG(arg);
1206
1207         opts->type = REBASE_MERGE;
1208         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
1209
1210         return 0;
1211 }
1212
1213 static enum empty_type parse_empty_value(const char *value)
1214 {
1215         if (!strcasecmp(value, "drop"))
1216                 return EMPTY_DROP;
1217         else if (!strcasecmp(value, "keep"))
1218                 return EMPTY_KEEP;
1219         else if (!strcasecmp(value, "ask"))
1220                 return EMPTY_ASK;
1221
1222         die(_("unrecognized empty type '%s'; valid values are \"drop\", \"keep\", and \"ask\"."), value);
1223 }
1224
1225 static int parse_opt_empty(const struct option *opt, const char *arg, int unset)
1226 {
1227         struct rebase_options *options = opt->value;
1228         enum empty_type value = parse_empty_value(arg);
1229
1230         BUG_ON_OPT_NEG(unset);
1231
1232         options->empty = value;
1233         return 0;
1234 }
1235
1236 static void NORETURN error_on_missing_default_upstream(void)
1237 {
1238         struct branch *current_branch = branch_get(NULL);
1239
1240         printf(_("%s\n"
1241                  "Please specify which branch you want to rebase against.\n"
1242                  "See git-rebase(1) for details.\n"
1243                  "\n"
1244                  "    git rebase '<branch>'\n"
1245                  "\n"),
1246                 current_branch ? _("There is no tracking information for "
1247                         "the current branch.") :
1248                         _("You are not currently on a branch."));
1249
1250         if (current_branch) {
1251                 const char *remote = current_branch->remote_name;
1252
1253                 if (!remote)
1254                         remote = _("<remote>");
1255
1256                 printf(_("If you wish to set tracking information for this "
1257                          "branch you can do so with:\n"
1258                          "\n"
1259                          "    git branch --set-upstream-to=%s/<branch> %s\n"
1260                          "\n"),
1261                        remote, current_branch->name);
1262         }
1263         exit(1);
1264 }
1265
1266 static void set_reflog_action(struct rebase_options *options)
1267 {
1268         const char *env;
1269         struct strbuf buf = STRBUF_INIT;
1270
1271         if (!is_merge(options))
1272                 return;
1273
1274         env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
1275         if (env && strcmp("rebase", env))
1276                 return; /* only override it if it is "rebase" */
1277
1278         strbuf_addf(&buf, "rebase (%s)", options->action);
1279         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, buf.buf, 1);
1280         strbuf_release(&buf);
1281 }
1282
1283 static int check_exec_cmd(const char *cmd)
1284 {
1285         if (strchr(cmd, '\n'))
1286                 return error(_("exec commands cannot contain newlines"));
1287
1288         /* Does the command consist purely of whitespace? */
1289         if (!cmd[strspn(cmd, " \t\r\f\v")])
1290                 return error(_("empty exec command"));
1291
1292         return 0;
1293 }
1294
1295 int cmd_rebase(int argc, const char **argv, const char *prefix)
1296 {
1297         struct rebase_options options = REBASE_OPTIONS_INIT;
1298         const char *branch_name;
1299         int ret, flags, total_argc, in_progress = 0;
1300         int keep_base = 0;
1301         int ok_to_skip_pre_rebase = 0;
1302         struct strbuf msg = STRBUF_INIT;
1303         struct strbuf revisions = STRBUF_INIT;
1304         struct strbuf buf = STRBUF_INIT;
1305         struct object_id merge_base;
1306         int ignore_whitespace = 0;
1307         enum action action = ACTION_NONE;
1308         const char *gpg_sign = NULL;
1309         struct string_list exec = STRING_LIST_INIT_NODUP;
1310         const char *rebase_merges = NULL;
1311         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
1312         struct object_id squash_onto;
1313         char *squash_onto_name = NULL;
1314         int reschedule_failed_exec = -1;
1315         int allow_preemptive_ff = 1;
1316         struct option builtin_rebase_options[] = {
1317                 OPT_STRING(0, "onto", &options.onto_name,
1318                            N_("revision"),
1319                            N_("rebase onto given branch instead of upstream")),
1320                 OPT_BOOL(0, "keep-base", &keep_base,
1321                          N_("use the merge-base of upstream and branch as the current base")),
1322                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
1323                          N_("allow pre-rebase hook to run")),
1324                 OPT_NEGBIT('q', "quiet", &options.flags,
1325                            N_("be quiet. implies --no-stat"),
1326                            REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
1327                 OPT_BIT('v', "verbose", &options.flags,
1328                         N_("display a diffstat of what changed upstream"),
1329                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
1330                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
1331                         N_("do not show diffstat of what changed upstream"),
1332                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
1333                 OPT_BOOL(0, "signoff", &options.signoff,
1334                          N_("add a Signed-off-by trailer to each commit")),
1335                 OPT_BOOL(0, "committer-date-is-author-date",
1336                          &options.committer_date_is_author_date,
1337                          N_("make committer date match author date")),
1338                 OPT_BOOL(0, "reset-author-date", &options.ignore_date,
1339                          N_("ignore author date and use current date")),
1340                 OPT_HIDDEN_BOOL(0, "ignore-date", &options.ignore_date,
1341                                 N_("synonym of --reset-author-date")),
1342                 OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
1343                                   N_("passed to 'git apply'"), 0),
1344                 OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
1345                          N_("ignore changes in whitespace")),
1346                 OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
1347                                   N_("action"), N_("passed to 'git apply'"), 0),
1348                 OPT_BIT('f', "force-rebase", &options.flags,
1349                         N_("cherry-pick all commits, even if unchanged"),
1350                         REBASE_FORCE),
1351                 OPT_BIT(0, "no-ff", &options.flags,
1352                         N_("cherry-pick all commits, even if unchanged"),
1353                         REBASE_FORCE),
1354                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
1355                             ACTION_CONTINUE),
1356                 OPT_CMDMODE(0, "skip", &action,
1357                             N_("skip current patch and continue"), ACTION_SKIP),
1358                 OPT_CMDMODE(0, "abort", &action,
1359                             N_("abort and check out the original branch"),
1360                             ACTION_ABORT),
1361                 OPT_CMDMODE(0, "quit", &action,
1362                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
1363                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
1364                             "during an interactive rebase"), ACTION_EDIT_TODO),
1365                 OPT_CMDMODE(0, "show-current-patch", &action,
1366                             N_("show the patch file being applied or merged"),
1367                             ACTION_SHOW_CURRENT_PATCH),
1368                 OPT_CALLBACK_F(0, "apply", &options, NULL,
1369                         N_("use apply strategies to rebase"),
1370                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1371                         parse_opt_am),
1372                 OPT_CALLBACK_F('m', "merge", &options, NULL,
1373                         N_("use merging strategies to rebase"),
1374                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1375                         parse_opt_merge),
1376                 OPT_CALLBACK_F('i', "interactive", &options, NULL,
1377                         N_("let the user edit the list of commits to rebase"),
1378                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1379                         parse_opt_interactive),
1380                 OPT_SET_INT_F('p', "preserve-merges", &options.type,
1381                               N_("(DEPRECATED) try to recreate merges instead of "
1382                                  "ignoring them"),
1383                               REBASE_PRESERVE_MERGES, PARSE_OPT_HIDDEN),
1384                 OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
1385                 OPT_CALLBACK_F(0, "empty", &options, "{drop,keep,ask}",
1386                                N_("how to handle commits that become empty"),
1387                                PARSE_OPT_NONEG, parse_opt_empty),
1388                 OPT_CALLBACK_F('k', "keep-empty", &options, NULL,
1389                         N_("keep commits which start empty"),
1390                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
1391                         parse_opt_keep_empty),
1392                 OPT_BOOL(0, "autosquash", &options.autosquash,
1393                          N_("move commits that begin with "
1394                             "squash!/fixup! under -i")),
1395                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
1396                         N_("GPG-sign commits"),
1397                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
1398                 OPT_AUTOSTASH(&options.autostash),
1399                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
1400                                 N_("add exec lines after each commit of the "
1401                                    "editable list")),
1402                 OPT_BOOL_F(0, "allow-empty-message",
1403                            &options.allow_empty_message,
1404                            N_("allow rebasing commits with empty messages"),
1405                            PARSE_OPT_HIDDEN),
1406                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
1407                         N_("mode"),
1408                         N_("try to rebase merges instead of skipping them"),
1409                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
1410                 OPT_BOOL(0, "fork-point", &options.fork_point,
1411                          N_("use 'merge-base --fork-point' to refine upstream")),
1412                 OPT_STRING('s', "strategy", &options.strategy,
1413                            N_("strategy"), N_("use the given merge strategy")),
1414                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
1415                                 N_("option"),
1416                                 N_("pass the argument through to the merge "
1417                                    "strategy")),
1418                 OPT_BOOL(0, "root", &options.root,
1419                          N_("rebase all reachable commits up to the root(s)")),
1420                 OPT_BOOL(0, "reschedule-failed-exec",
1421                          &reschedule_failed_exec,
1422                          N_("automatically re-schedule any `exec` that fails")),
1423                 OPT_BOOL(0, "reapply-cherry-picks", &options.reapply_cherry_picks,
1424                          N_("apply all changes, even those already present upstream")),
1425                 OPT_END(),
1426         };
1427         int i;
1428
1429         if (argc == 2 && !strcmp(argv[1], "-h"))
1430                 usage_with_options(builtin_rebase_usage,
1431                                    builtin_rebase_options);
1432
1433         options.allow_empty_message = 1;
1434         git_config(rebase_config, &options);
1435         /* options.gpg_sign_opt will be either "-S" or NULL */
1436         gpg_sign = options.gpg_sign_opt ? "" : NULL;
1437         FREE_AND_NULL(options.gpg_sign_opt);
1438
1439         strbuf_reset(&buf);
1440         strbuf_addf(&buf, "%s/applying", apply_dir());
1441         if(file_exists(buf.buf))
1442                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
1443
1444         if (is_directory(apply_dir())) {
1445                 options.type = REBASE_APPLY;
1446                 options.state_dir = apply_dir();
1447         } else if (is_directory(merge_dir())) {
1448                 strbuf_reset(&buf);
1449                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
1450                 if (is_directory(buf.buf)) {
1451                         options.type = REBASE_PRESERVE_MERGES;
1452                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1453                 } else {
1454                         strbuf_reset(&buf);
1455                         strbuf_addf(&buf, "%s/interactive", merge_dir());
1456                         if(file_exists(buf.buf)) {
1457                                 options.type = REBASE_MERGE;
1458                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1459                         } else
1460                                 options.type = REBASE_MERGE;
1461                 }
1462                 options.state_dir = merge_dir();
1463         }
1464
1465         if (options.type != REBASE_UNSPECIFIED)
1466                 in_progress = 1;
1467
1468         total_argc = argc;
1469         argc = parse_options(argc, argv, prefix,
1470                              builtin_rebase_options,
1471                              builtin_rebase_usage, 0);
1472
1473         if (action != ACTION_NONE && total_argc != 2) {
1474                 usage_with_options(builtin_rebase_usage,
1475                                    builtin_rebase_options);
1476         }
1477
1478         if (argc > 2)
1479                 usage_with_options(builtin_rebase_usage,
1480                                    builtin_rebase_options);
1481
1482         if (options.type == REBASE_PRESERVE_MERGES)
1483                 warning(_("git rebase --preserve-merges is deprecated. "
1484                           "Use --rebase-merges instead."));
1485
1486         if (keep_base) {
1487                 if (options.onto_name)
1488                         die(_("cannot combine '--keep-base' with '--onto'"));
1489                 if (options.root)
1490                         die(_("cannot combine '--keep-base' with '--root'"));
1491         }
1492
1493         if (options.root && options.fork_point > 0)
1494                 die(_("cannot combine '--root' with '--fork-point'"));
1495
1496         if (action != ACTION_NONE && !in_progress)
1497                 die(_("No rebase in progress?"));
1498         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
1499
1500         if (action == ACTION_EDIT_TODO && !is_merge(&options))
1501                 die(_("The --edit-todo action can only be used during "
1502                       "interactive rebase."));
1503
1504         if (trace2_is_enabled()) {
1505                 if (is_merge(&options))
1506                         trace2_cmd_mode("interactive");
1507                 else if (exec.nr)
1508                         trace2_cmd_mode("interactive-exec");
1509                 else
1510                         trace2_cmd_mode(action_names[action]);
1511         }
1512
1513         switch (action) {
1514         case ACTION_CONTINUE: {
1515                 struct object_id head;
1516                 struct lock_file lock_file = LOCK_INIT;
1517                 int fd;
1518
1519                 options.action = "continue";
1520                 set_reflog_action(&options);
1521
1522                 /* Sanity check */
1523                 if (get_oid("HEAD", &head))
1524                         die(_("Cannot read HEAD"));
1525
1526                 fd = hold_locked_index(&lock_file, 0);
1527                 if (repo_read_index(the_repository) < 0)
1528                         die(_("could not read index"));
1529                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
1530                               NULL);
1531                 if (0 <= fd)
1532                         repo_update_index_if_able(the_repository, &lock_file);
1533                 rollback_lock_file(&lock_file);
1534
1535                 if (has_unstaged_changes(the_repository, 1)) {
1536                         puts(_("You must edit all merge conflicts and then\n"
1537                                "mark them as resolved using git add"));
1538                         exit(1);
1539                 }
1540                 if (read_basic_state(&options))
1541                         exit(1);
1542                 goto run_rebase;
1543         }
1544         case ACTION_SKIP: {
1545                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1546
1547                 options.action = "skip";
1548                 set_reflog_action(&options);
1549
1550                 rerere_clear(the_repository, &merge_rr);
1551                 string_list_clear(&merge_rr, 1);
1552
1553                 if (reset_head(the_repository, NULL, "reset", NULL, RESET_HEAD_HARD,
1554                                NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
1555                         die(_("could not discard worktree changes"));
1556                 remove_branch_state(the_repository, 0);
1557                 if (read_basic_state(&options))
1558                         exit(1);
1559                 goto run_rebase;
1560         }
1561         case ACTION_ABORT: {
1562                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1563                 options.action = "abort";
1564                 set_reflog_action(&options);
1565
1566                 rerere_clear(the_repository, &merge_rr);
1567                 string_list_clear(&merge_rr, 1);
1568
1569                 if (read_basic_state(&options))
1570                         exit(1);
1571                 if (reset_head(the_repository, &options.orig_head, "reset",
1572                                options.head_name, RESET_HEAD_HARD,
1573                                NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
1574                         die(_("could not move back to %s"),
1575                             oid_to_hex(&options.orig_head));
1576                 remove_branch_state(the_repository, 0);
1577                 ret = !!finish_rebase(&options);
1578                 goto cleanup;
1579         }
1580         case ACTION_QUIT: {
1581                 save_autostash(state_dir_path("autostash", &options));
1582                 if (options.type == REBASE_MERGE) {
1583                         struct replay_opts replay = REPLAY_OPTS_INIT;
1584
1585                         replay.action = REPLAY_INTERACTIVE_REBASE;
1586                         ret = !!sequencer_remove_state(&replay);
1587                 } else {
1588                         strbuf_reset(&buf);
1589                         strbuf_addstr(&buf, options.state_dir);
1590                         ret = !!remove_dir_recursively(&buf, 0);
1591                         if (ret)
1592                                 error(_("could not remove '%s'"),
1593                                        options.state_dir);
1594                 }
1595                 goto cleanup;
1596         }
1597         case ACTION_EDIT_TODO:
1598                 options.action = "edit-todo";
1599                 options.dont_finish_rebase = 1;
1600                 goto run_rebase;
1601         case ACTION_SHOW_CURRENT_PATCH:
1602                 options.action = "show-current-patch";
1603                 options.dont_finish_rebase = 1;
1604                 goto run_rebase;
1605         case ACTION_NONE:
1606                 break;
1607         default:
1608                 BUG("action: %d", action);
1609         }
1610
1611         /* Make sure no rebase is in progress */
1612         if (in_progress) {
1613                 const char *last_slash = strrchr(options.state_dir, '/');
1614                 const char *state_dir_base =
1615                         last_slash ? last_slash + 1 : options.state_dir;
1616                 const char *cmd_live_rebase =
1617                         "git rebase (--continue | --abort | --skip)";
1618                 strbuf_reset(&buf);
1619                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1620                 die(_("It seems that there is already a %s directory, and\n"
1621                       "I wonder if you are in the middle of another rebase.  "
1622                       "If that is the\n"
1623                       "case, please try\n\t%s\n"
1624                       "If that is not the case, please\n\t%s\n"
1625                       "and run me again.  I am stopping in case you still "
1626                       "have something\n"
1627                       "valuable there.\n"),
1628                     state_dir_base, cmd_live_rebase, buf.buf);
1629         }
1630
1631         if ((options.flags & REBASE_INTERACTIVE_EXPLICIT) ||
1632             (action != ACTION_NONE) ||
1633             (exec.nr > 0) ||
1634             options.autosquash) {
1635                 allow_preemptive_ff = 0;
1636         }
1637         if (options.committer_date_is_author_date || options.ignore_date)
1638                 options.flags |= REBASE_FORCE;
1639
1640         for (i = 0; i < options.git_am_opts.nr; i++) {
1641                 const char *option = options.git_am_opts.v[i], *p;
1642                 if (!strcmp(option, "--whitespace=fix") ||
1643                     !strcmp(option, "--whitespace=strip"))
1644                         allow_preemptive_ff = 0;
1645                 else if (skip_prefix(option, "-C", &p)) {
1646                         while (*p)
1647                                 if (!isdigit(*(p++)))
1648                                         die(_("switch `C' expects a "
1649                                               "numerical value"));
1650                 } else if (skip_prefix(option, "--whitespace=", &p)) {
1651                         if (*p && strcmp(p, "warn") && strcmp(p, "nowarn") &&
1652                             strcmp(p, "error") && strcmp(p, "error-all"))
1653                                 die("Invalid whitespace option: '%s'", p);
1654                 }
1655         }
1656
1657         for (i = 0; i < exec.nr; i++)
1658                 if (check_exec_cmd(exec.items[i].string))
1659                         exit(1);
1660
1661         if (!(options.flags & REBASE_NO_QUIET))
1662                 strvec_push(&options.git_am_opts, "-q");
1663
1664         if (options.empty != EMPTY_UNSPECIFIED)
1665                 imply_merge(&options, "--empty");
1666
1667         if (options.reapply_cherry_picks)
1668                 imply_merge(&options, "--reapply-cherry-picks");
1669
1670         if (gpg_sign)
1671                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1672
1673         if (exec.nr) {
1674                 int i;
1675
1676                 imply_merge(&options, "--exec");
1677
1678                 strbuf_reset(&buf);
1679                 for (i = 0; i < exec.nr; i++)
1680                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1681                 options.cmd = xstrdup(buf.buf);
1682         }
1683
1684         if (rebase_merges) {
1685                 if (!*rebase_merges)
1686                         ; /* default mode; do nothing */
1687                 else if (!strcmp("rebase-cousins", rebase_merges))
1688                         options.rebase_cousins = 1;
1689                 else if (strcmp("no-rebase-cousins", rebase_merges))
1690                         die(_("Unknown mode: %s"), rebase_merges);
1691                 options.rebase_merges = 1;
1692                 imply_merge(&options, "--rebase-merges");
1693         }
1694
1695         if (options.type == REBASE_APPLY) {
1696                 if (ignore_whitespace)
1697                         strvec_push(&options.git_am_opts,
1698                                     "--ignore-whitespace");
1699                 if (options.committer_date_is_author_date)
1700                         strvec_push(&options.git_am_opts,
1701                                     "--committer-date-is-author-date");
1702                 if (options.ignore_date)
1703                         strvec_push(&options.git_am_opts, "--ignore-date");
1704         } else {
1705                 /* REBASE_MERGE and PRESERVE_MERGES */
1706                 if (ignore_whitespace) {
1707                         string_list_append(&strategy_options,
1708                                            "ignore-space-change");
1709                 }
1710         }
1711
1712         if (strategy_options.nr) {
1713                 int i;
1714
1715                 if (!options.strategy)
1716                         options.strategy = "recursive";
1717
1718                 strbuf_reset(&buf);
1719                 for (i = 0; i < strategy_options.nr; i++)
1720                         strbuf_addf(&buf, " --%s",
1721                                     strategy_options.items[i].string);
1722                 options.strategy_opts = xstrdup(buf.buf);
1723         }
1724
1725         if (options.strategy) {
1726                 options.strategy = xstrdup(options.strategy);
1727                 switch (options.type) {
1728                 case REBASE_APPLY:
1729                         die(_("--strategy requires --merge or --interactive"));
1730                 case REBASE_MERGE:
1731                 case REBASE_PRESERVE_MERGES:
1732                         /* compatible */
1733                         break;
1734                 case REBASE_UNSPECIFIED:
1735                         options.type = REBASE_MERGE;
1736                         break;
1737                 default:
1738                         BUG("unhandled rebase type (%d)", options.type);
1739                 }
1740         }
1741
1742         if (options.type == REBASE_MERGE)
1743                 imply_merge(&options, "--merge");
1744
1745         if (options.root && !options.onto_name)
1746                 imply_merge(&options, "--root without --onto");
1747
1748         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1749                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1750
1751         if (options.git_am_opts.nr || options.type == REBASE_APPLY) {
1752                 /* all am options except -q are compatible only with --apply */
1753                 for (i = options.git_am_opts.nr - 1; i >= 0; i--)
1754                         if (strcmp(options.git_am_opts.v[i], "-q"))
1755                                 break;
1756
1757                 if (i >= 0) {
1758                         if (is_merge(&options))
1759                                 die(_("cannot combine apply options with "
1760                                       "merge options"));
1761                         else
1762                                 options.type = REBASE_APPLY;
1763                 }
1764         }
1765
1766         if (options.type == REBASE_UNSPECIFIED) {
1767                 if (!strcmp(options.default_backend, "merge"))
1768                         imply_merge(&options, "--merge");
1769                 else if (!strcmp(options.default_backend, "apply"))
1770                         options.type = REBASE_APPLY;
1771                 else
1772                         die(_("Unknown rebase backend: %s"),
1773                             options.default_backend);
1774         }
1775
1776         if (options.type == REBASE_MERGE &&
1777             !options.strategy &&
1778             getenv("GIT_TEST_MERGE_ALGORITHM"))
1779                 options.strategy = xstrdup(getenv("GIT_TEST_MERGE_ALGORITHM"));
1780
1781         switch (options.type) {
1782         case REBASE_MERGE:
1783         case REBASE_PRESERVE_MERGES:
1784                 options.state_dir = merge_dir();
1785                 break;
1786         case REBASE_APPLY:
1787                 options.state_dir = apply_dir();
1788                 break;
1789         default:
1790                 BUG("options.type was just set above; should be unreachable.");
1791         }
1792
1793         if (options.empty == EMPTY_UNSPECIFIED) {
1794                 if (options.flags & REBASE_INTERACTIVE_EXPLICIT)
1795                         options.empty = EMPTY_ASK;
1796                 else if (exec.nr > 0)
1797                         options.empty = EMPTY_KEEP;
1798                 else
1799                         options.empty = EMPTY_DROP;
1800         }
1801         if (reschedule_failed_exec > 0 && !is_merge(&options))
1802                 die(_("--reschedule-failed-exec requires "
1803                       "--exec or --interactive"));
1804         if (reschedule_failed_exec >= 0)
1805                 options.reschedule_failed_exec = reschedule_failed_exec;
1806
1807         if (options.signoff) {
1808                 if (options.type == REBASE_PRESERVE_MERGES)
1809                         die("cannot combine '--signoff' with "
1810                             "'--preserve-merges'");
1811                 strvec_push(&options.git_am_opts, "--signoff");
1812                 options.flags |= REBASE_FORCE;
1813         }
1814
1815         if (options.type == REBASE_PRESERVE_MERGES) {
1816                 /*
1817                  * Note: incompatibility with --signoff handled in signoff block above
1818                  * Note: incompatibility with --interactive is just a strong warning;
1819                  *       git-rebase.txt caveats with "unless you know what you are doing"
1820                  */
1821                 if (options.rebase_merges)
1822                         die(_("cannot combine '--preserve-merges' with "
1823                               "'--rebase-merges'"));
1824
1825                 if (options.reschedule_failed_exec)
1826                         die(_("error: cannot combine '--preserve-merges' with "
1827                               "'--reschedule-failed-exec'"));
1828         }
1829
1830         if (!options.root) {
1831                 if (argc < 1) {
1832                         struct branch *branch;
1833
1834                         branch = branch_get(NULL);
1835                         options.upstream_name = branch_get_upstream(branch,
1836                                                                     NULL);
1837                         if (!options.upstream_name)
1838                                 error_on_missing_default_upstream();
1839                         if (options.fork_point < 0)
1840                                 options.fork_point = 1;
1841                 } else {
1842                         options.upstream_name = argv[0];
1843                         argc--;
1844                         argv++;
1845                         if (!strcmp(options.upstream_name, "-"))
1846                                 options.upstream_name = "@{-1}";
1847                 }
1848                 options.upstream = peel_committish(options.upstream_name);
1849                 if (!options.upstream)
1850                         die(_("invalid upstream '%s'"), options.upstream_name);
1851                 options.upstream_arg = options.upstream_name;
1852         } else {
1853                 if (!options.onto_name) {
1854                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1855                                         &squash_onto, NULL, NULL) < 0)
1856                                 die(_("Could not create new root commit"));
1857                         options.squash_onto = &squash_onto;
1858                         options.onto_name = squash_onto_name =
1859                                 xstrdup(oid_to_hex(&squash_onto));
1860                 } else
1861                         options.root_with_onto = 1;
1862
1863                 options.upstream_name = NULL;
1864                 options.upstream = NULL;
1865                 if (argc > 1)
1866                         usage_with_options(builtin_rebase_usage,
1867                                            builtin_rebase_options);
1868                 options.upstream_arg = "--root";
1869         }
1870
1871         /* Make sure the branch to rebase onto is valid. */
1872         if (keep_base) {
1873                 strbuf_reset(&buf);
1874                 strbuf_addstr(&buf, options.upstream_name);
1875                 strbuf_addstr(&buf, "...");
1876                 options.onto_name = xstrdup(buf.buf);
1877         } else if (!options.onto_name)
1878                 options.onto_name = options.upstream_name;
1879         if (strstr(options.onto_name, "...")) {
1880                 if (get_oid_mb(options.onto_name, &merge_base) < 0) {
1881                         if (keep_base)
1882                                 die(_("'%s': need exactly one merge base with branch"),
1883                                     options.upstream_name);
1884                         else
1885                                 die(_("'%s': need exactly one merge base"),
1886                                     options.onto_name);
1887                 }
1888                 options.onto = lookup_commit_or_die(&merge_base,
1889                                                     options.onto_name);
1890         } else {
1891                 options.onto = peel_committish(options.onto_name);
1892                 if (!options.onto)
1893                         die(_("Does not point to a valid commit '%s'"),
1894                                 options.onto_name);
1895         }
1896
1897         /*
1898          * If the branch to rebase is given, that is the branch we will rebase
1899          * branch_name -- branch/commit being rebased, or
1900          *                HEAD (already detached)
1901          * orig_head -- commit object name of tip of the branch before rebasing
1902          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1903          */
1904         if (argc == 1) {
1905                 /* Is it "rebase other branchname" or "rebase other commit"? */
1906                 branch_name = argv[0];
1907                 options.switch_to = argv[0];
1908
1909                 /* Is it a local branch? */
1910                 strbuf_reset(&buf);
1911                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1912                 if (!read_ref(buf.buf, &options.orig_head)) {
1913                         die_if_checked_out(buf.buf, 1);
1914                         options.head_name = xstrdup(buf.buf);
1915                 /* If not is it a valid ref (branch or commit)? */
1916                 } else if (!get_oid(branch_name, &options.orig_head) &&
1917                            lookup_commit_reference(the_repository,
1918                                                    &options.orig_head))
1919                         options.head_name = NULL;
1920                 else
1921                         die(_("fatal: no such branch/commit '%s'"),
1922                             branch_name);
1923         } else if (argc == 0) {
1924                 /* Do not need to switch branches, we are already on it. */
1925                 options.head_name =
1926                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1927                                          &flags));
1928                 if (!options.head_name)
1929                         die(_("No such ref: %s"), "HEAD");
1930                 if (flags & REF_ISSYMREF) {
1931                         if (!skip_prefix(options.head_name,
1932                                          "refs/heads/", &branch_name))
1933                                 branch_name = options.head_name;
1934
1935                 } else {
1936                         FREE_AND_NULL(options.head_name);
1937                         branch_name = "HEAD";
1938                 }
1939                 if (get_oid("HEAD", &options.orig_head))
1940                         die(_("Could not resolve HEAD to a revision"));
1941         } else
1942                 BUG("unexpected number of arguments left to parse");
1943
1944         if (options.fork_point > 0) {
1945                 struct commit *head =
1946                         lookup_commit_reference(the_repository,
1947                                                 &options.orig_head);
1948                 options.restrict_revision =
1949                         get_fork_point(options.upstream_name, head);
1950         }
1951
1952         if (repo_read_index(the_repository) < 0)
1953                 die(_("could not read index"));
1954
1955         if (options.autostash) {
1956                 create_autostash(the_repository, state_dir_path("autostash", &options),
1957                                  DEFAULT_REFLOG_ACTION);
1958         }
1959
1960         if (require_clean_work_tree(the_repository, "rebase",
1961                                     _("Please commit or stash them."), 1, 1)) {
1962                 ret = 1;
1963                 goto cleanup;
1964         }
1965
1966         /*
1967          * Now we are rebasing commits upstream..orig_head (or with --root,
1968          * everything leading up to orig_head) on top of onto.
1969          */
1970
1971         /*
1972          * Check if we are already based on onto with linear history,
1973          * in which case we could fast-forward without replacing the commits
1974          * with new commits recreated by replaying their changes.
1975          *
1976          * Note that can_fast_forward() initializes merge_base, so we have to
1977          * call it before checking allow_preemptive_ff.
1978          */
1979         if (can_fast_forward(options.onto, options.upstream, options.restrict_revision,
1980                     &options.orig_head, &merge_base) &&
1981             allow_preemptive_ff) {
1982                 int flag;
1983
1984                 if (!(options.flags & REBASE_FORCE)) {
1985                         /* Lazily switch to the target branch if needed... */
1986                         if (options.switch_to) {
1987                                 strbuf_reset(&buf);
1988                                 strbuf_addf(&buf, "%s: checkout %s",
1989                                             getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
1990                                             options.switch_to);
1991                                 if (reset_head(the_repository,
1992                                                &options.orig_head, "checkout",
1993                                                options.head_name,
1994                                                RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
1995                                                NULL, buf.buf,
1996                                                DEFAULT_REFLOG_ACTION) < 0) {
1997                                         ret = !!error(_("could not switch to "
1998                                                         "%s"),
1999                                                       options.switch_to);
2000                                         goto cleanup;
2001                                 }
2002                         }
2003
2004                         if (!(options.flags & REBASE_NO_QUIET))
2005                                 ; /* be quiet */
2006                         else if (!strcmp(branch_name, "HEAD") &&
2007                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
2008                                 puts(_("HEAD is up to date."));
2009                         else
2010                                 printf(_("Current branch %s is up to date.\n"),
2011                                        branch_name);
2012                         ret = !!finish_rebase(&options);
2013                         goto cleanup;
2014                 } else if (!(options.flags & REBASE_NO_QUIET))
2015                         ; /* be quiet */
2016                 else if (!strcmp(branch_name, "HEAD") &&
2017                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
2018                         puts(_("HEAD is up to date, rebase forced."));
2019                 else
2020                         printf(_("Current branch %s is up to date, rebase "
2021                                  "forced.\n"), branch_name);
2022         }
2023
2024         /* If a hook exists, give it a chance to interrupt*/
2025         if (!ok_to_skip_pre_rebase &&
2026             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
2027                         argc ? argv[0] : NULL, NULL))
2028                 die(_("The pre-rebase hook refused to rebase."));
2029
2030         if (options.flags & REBASE_DIFFSTAT) {
2031                 struct diff_options opts;
2032
2033                 if (options.flags & REBASE_VERBOSE) {
2034                         if (is_null_oid(&merge_base))
2035                                 printf(_("Changes to %s:\n"),
2036                                        oid_to_hex(&options.onto->object.oid));
2037                         else
2038                                 printf(_("Changes from %s to %s:\n"),
2039                                        oid_to_hex(&merge_base),
2040                                        oid_to_hex(&options.onto->object.oid));
2041                 }
2042
2043                 /* We want color (if set), but no pager */
2044                 diff_setup(&opts);
2045                 opts.stat_width = -1; /* use full terminal width */
2046                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
2047                 opts.output_format |=
2048                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
2049                 opts.detect_rename = DIFF_DETECT_RENAME;
2050                 diff_setup_done(&opts);
2051                 diff_tree_oid(is_null_oid(&merge_base) ?
2052                               the_hash_algo->empty_tree : &merge_base,
2053                               &options.onto->object.oid, "", &opts);
2054                 diffcore_std(&opts);
2055                 diff_flush(&opts);
2056         }
2057
2058         if (is_merge(&options))
2059                 goto run_rebase;
2060
2061         /* Detach HEAD and reset the tree */
2062         if (options.flags & REBASE_NO_QUIET)
2063                 printf(_("First, rewinding head to replay your work on top of "
2064                          "it...\n"));
2065
2066         strbuf_addf(&msg, "%s: checkout %s",
2067                     getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
2068         if (reset_head(the_repository, &options.onto->object.oid, "checkout", NULL,
2069                        RESET_HEAD_DETACH | RESET_ORIG_HEAD |
2070                        RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
2071                        NULL, msg.buf, DEFAULT_REFLOG_ACTION))
2072                 die(_("Could not detach HEAD"));
2073         strbuf_release(&msg);
2074
2075         /*
2076          * If the onto is a proper descendant of the tip of the branch, then
2077          * we just fast-forwarded.
2078          */
2079         strbuf_reset(&msg);
2080         if (oideq(&merge_base, &options.orig_head)) {
2081                 printf(_("Fast-forwarded %s to %s.\n"),
2082                         branch_name, options.onto_name);
2083                 strbuf_addf(&msg, "rebase finished: %s onto %s",
2084                         options.head_name ? options.head_name : "detached HEAD",
2085                         oid_to_hex(&options.onto->object.oid));
2086                 reset_head(the_repository, NULL, "Fast-forwarded", options.head_name,
2087                            RESET_HEAD_REFS_ONLY, "HEAD", msg.buf,
2088                            DEFAULT_REFLOG_ACTION);
2089                 strbuf_release(&msg);
2090                 ret = !!finish_rebase(&options);
2091                 goto cleanup;
2092         }
2093
2094         strbuf_addf(&revisions, "%s..%s",
2095                     options.root ? oid_to_hex(&options.onto->object.oid) :
2096                     (options.restrict_revision ?
2097                      oid_to_hex(&options.restrict_revision->object.oid) :
2098                      oid_to_hex(&options.upstream->object.oid)),
2099                     oid_to_hex(&options.orig_head));
2100
2101         options.revisions = revisions.buf;
2102
2103 run_rebase:
2104         ret = !!run_specific_rebase(&options, action);
2105
2106 cleanup:
2107         strbuf_release(&buf);
2108         strbuf_release(&revisions);
2109         free(options.head_name);
2110         free(options.gpg_sign_opt);
2111         free(options.cmd);
2112         strbuf_release(&options.git_format_patch_opt);
2113         free(squash_onto_name);
2114         return ret;
2115 }