builtin/bisect--helper.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "parse-options.h"
   4 #include "bisect.h"
   5 #include "refs.h"
   6 #include "dir.h"
   7 #include "argv-array.h"
   8 #include "run-command.h"
   9 #include "prompt.h"
  10 #include "quote.h"
  11
  12 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
  13 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
  14 static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
  15 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
  16 static GIT_PATH_FUNC(git_path_bisect_head, "BISECT_HEAD")
  17 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
  18 static GIT_PATH_FUNC(git_path_head_name, "head-name")
  19 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
  20
  21 static const char * const git_bisect_helper_usage[] = {
  22         N_("git bisect--helper --next-all [--no-checkout]"),
  23         N_("git bisect--helper --write-terms <bad_term> <good_term>"),
  24         N_("git bisect--helper --bisect-clean-state"),
  25         N_("git bisect--helper --bisect-reset [<commit>]"),
  26         N_("git bisect--helper --bisect-write [--no-log] <state> <revision> <good_term> <bad_term>"),
  27         N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
  28         N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
  29         N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
  30         N_("git bisect--helper --bisect-start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
  31                                              "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
  32         NULL
  33 };
  34
  35 struct bisect_terms {
  36         char *term_good;
  37         char *term_bad;
  38 };
  39
  40 static void free_terms(struct bisect_terms *terms)
  41 {
  42         FREE_AND_NULL(terms->term_good);
  43         FREE_AND_NULL(terms->term_bad);
  44 }
  45
  46 static void set_terms(struct bisect_terms *terms, const char *bad,
  47                       const char *good)
  48 {
  49         free((void *)terms->term_good);
  50         terms->term_good = xstrdup(good);
  51         free((void *)terms->term_bad);
  52         terms->term_bad = xstrdup(bad);
  53 }
  54
  55 static const char *vocab_bad = "bad|new";
  56 static const char *vocab_good = "good|old";
  57
  58 /*
  59  * Check whether the string `term` belongs to the set of strings
  60  * included in the variable arguments.
  61  */
  62 LAST_ARG_MUST_BE_NULL
  63 static int one_of(const char *term, ...)
  64 {
  65         int res = 0;
  66         va_list matches;
  67         const char *match;
  68
  69         va_start(matches, term);
  70         while (!res && (match = va_arg(matches, const char *)))
  71                 res = !strcmp(term, match);
  72         va_end(matches);
  73
  74         return res;
  75 }
  76
  77 static int check_term_format(const char *term, const char *orig_term)
  78 {
  79         int res;
  80         char *new_term = xstrfmt("refs/bisect/%s", term);
  81
  82         res = check_refname_format(new_term, 0);
  83         free(new_term);
  84
  85         if (res)
  86                 return error(_("'%s' is not a valid term"), term);
  87
  88         if (one_of(term, "help", "start", "skip", "next", "reset",
  89                         "visualize", "view", "replay", "log", "run", "terms", NULL))
  90                 return error(_("can't use the builtin command '%s' as a term"), term);
  91
  92         /*
  93          * In theory, nothing prevents swapping completely good and bad,
  94          * but this situation could be confusing and hasn't been tested
  95          * enough. Forbid it for now.
  96          */
  97
  98         if ((strcmp(orig_term, "bad") && one_of(term, "bad", "new", NULL)) ||
  99                  (strcmp(orig_term, "good") && one_of(term, "good", "old", NULL)))
 100                 return error(_("can't change the meaning of the term '%s'"), term);
 101
 102         return 0;
 103 }
 104
 105 static int write_terms(const char *bad, const char *good)
 106 {
 107         FILE *fp = NULL;
 108         int res;
 109
 110         if (!strcmp(bad, good))
 111                 return error(_("please use two different terms"));
 112
 113         if (check_term_format(bad, "bad") || check_term_format(good, "good"))
 114                 return -1;
 115
 116         fp = fopen(git_path_bisect_terms(), "w");
 117         if (!fp)
 118                 return error_errno(_("could not open the file BISECT_TERMS"));
 119
 120         res = fprintf(fp, "%s\n%s\n", bad, good);
 121         res |= fclose(fp);
 122         return (res < 0) ? -1 : 0;
 123 }
 124
 125 static int is_expected_rev(const char *expected_hex)
 126 {
 127         struct strbuf actual_hex = STRBUF_INIT;
 128         int res = 0;
 129         if (strbuf_read_file(&actual_hex, git_path_bisect_expected_rev(), 0) >= 40) {
 130                 strbuf_trim(&actual_hex);
 131                 res = !strcmp(actual_hex.buf, expected_hex);
 132         }
 133         strbuf_release(&actual_hex);
 134         return res;
 135 }
 136
 137 static void check_expected_revs(const char **revs, int rev_nr)
 138 {
 139         int i;
 140
 141         for (i = 0; i < rev_nr; i++) {
 142                 if (!is_expected_rev(revs[i])) {
 143                         unlink_or_warn(git_path_bisect_ancestors_ok());
 144                         unlink_or_warn(git_path_bisect_expected_rev());
 145                 }
 146         }
 147 }
 148
 149 static int bisect_reset(const char *commit)
 150 {
 151         struct strbuf branch = STRBUF_INIT;
 152
 153         if (!commit) {
 154                 if (strbuf_read_file(&branch, git_path_bisect_start(), 0) < 1) {
 155                         printf(_("We are not bisecting.\n"));
 156                         return 0;
 157                 }
 158                 strbuf_rtrim(&branch);
 159         } else {
 160                 struct object_id oid;
 161
 162                 if (get_oid_commit(commit, &oid))
 163                         return error(_("'%s' is not a valid commit"), commit);
 164                 strbuf_addstr(&branch, commit);
 165         }
 166
 167         if (!file_exists(git_path_bisect_head())) {
 168                 struct argv_array argv = ARGV_ARRAY_INIT;
 169
 170                 argv_array_pushl(&argv, "checkout", branch.buf, "--", NULL);
 171                 if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
 172                         strbuf_release(&branch);
 173                         argv_array_clear(&argv);
 174                         return error(_("could not check out original"
 175                                        " HEAD '%s'. Try 'git bisect"
 176                                        " reset <commit>'."), branch.buf);
 177                 }
 178                 argv_array_clear(&argv);
 179         }
 180
 181         strbuf_release(&branch);
 182         return bisect_clean_state();
 183 }
 184
 185 static void log_commit(FILE *fp, char *fmt, const char *state,
 186                        struct commit *commit)
 187 {
 188         struct pretty_print_context pp = {0};
 189         struct strbuf commit_msg = STRBUF_INIT;
 190         char *label = xstrfmt(fmt, state);
 191
 192         format_commit_message(commit, "%s", &commit_msg, &pp);
 193
 194         fprintf(fp, "# %s: [%s] %s\n", label, oid_to_hex(&commit->object.oid),
 195                 commit_msg.buf);
 196
 197         strbuf_release(&commit_msg);
 198         free(label);
 199 }
 200
 201 static int bisect_write(const char *state, const char *rev,
 202                         const struct bisect_terms *terms, int nolog)
 203 {
 204         struct strbuf tag = STRBUF_INIT;
 205         struct object_id oid;
 206         struct commit *commit;
 207         FILE *fp = NULL;
 208         int retval = 0;
 209
 210         if (!strcmp(state, terms->term_bad)) {
 211                 strbuf_addf(&tag, "refs/bisect/%s", state);
 212         } else if (one_of(state, terms->term_good, "skip", NULL)) {
 213                 strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
 214         } else {
 215                 retval = error(_("Bad bisect_write argument: %s"), state);
 216                 goto finish;
 217         }
 218
 219         if (get_oid(rev, &oid)) {
 220                 retval = error(_("couldn't get the oid of the rev '%s'"), rev);
 221                 goto finish;
 222         }
 223
 224         if (update_ref(NULL, tag.buf, &oid, NULL, 0,
 225                        UPDATE_REFS_MSG_ON_ERR)) {
 226                 retval = -1;
 227                 goto finish;
 228         }
 229
 230         fp = fopen(git_path_bisect_log(), "a");
 231         if (!fp) {
 232                 retval = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
 233                 goto finish;
 234         }
 235
 236         commit = lookup_commit_reference(the_repository, &oid);
 237         log_commit(fp, "%s", state, commit);
 238
 239         if (!nolog)
 240                 fprintf(fp, "git bisect %s %s\n", state, rev);
 241
 242 finish:
 243         if (fp)
 244                 fclose(fp);
 245         strbuf_release(&tag);
 246         return retval;
 247 }
 248
 249 static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
 250 {
 251         int has_term_file = !is_empty_or_missing_file(git_path_bisect_terms());
 252
 253         if (one_of(cmd, "skip", "start", "terms", NULL))
 254                 return 0;
 255
 256         if (has_term_file && strcmp(cmd, terms->term_bad) &&
 257             strcmp(cmd, terms->term_good))
 258                 return error(_("Invalid command: you're currently in a "
 259                                 "%s/%s bisect"), terms->term_bad,
 260                                 terms->term_good);
 261
 262         if (!has_term_file) {
 263                 if (one_of(cmd, "bad", "good", NULL)) {
 264                         set_terms(terms, "bad", "good");
 265                         return write_terms(terms->term_bad, terms->term_good);
 266                 }
 267                 if (one_of(cmd, "new", "old", NULL)) {
 268                         set_terms(terms, "new", "old");
 269                         return write_terms(terms->term_bad, terms->term_good);
 270                 }
 271         }
 272
 273         return 0;
 274 }
 275
 276 static int mark_good(const char *refname, const struct object_id *oid,
 277                      int flag, void *cb_data)
 278 {
 279         int *m_good = (int *)cb_data;
 280         *m_good = 0;
 281         return 1;
 282 }
 283
 284 static const char *need_bad_and_good_revision_warning =
 285         N_("You need to give me at least one %s and %s revision.\n"
 286            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 287
 288 static const char *need_bisect_start_warning =
 289         N_("You need to start by \"git bisect start\".\n"
 290            "You then need to give me at least one %s and %s revision.\n"
 291            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 292
 293 static int bisect_next_check(const struct bisect_terms *terms,
 294                              const char *current_term)
 295 {
 296         int missing_good = 1, missing_bad = 1, retval = 0;
 297         const char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
 298         const char *good_glob = xstrfmt("%s-*", terms->term_good);
 299
 300         if (ref_exists(bad_ref))
 301                 missing_bad = 0;
 302
 303         for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
 304                              (void *) &missing_good);
 305
 306         if (!missing_good && !missing_bad)
 307                 goto finish;
 308
 309         if (!current_term) {
 310                 retval = -1;
 311                 goto finish;
 312         }
 313
 314         if (missing_good && !missing_bad &&
 315             !strcmp(current_term, terms->term_good)) {
 316                 char *yesno;
 317                 /*
 318                  * have bad (or new) but not good (or old). We could bisect
 319                  * although this is less optimum.
 320                  */
 321                 warning(_("bisecting only with a %s commit"), terms->term_bad);
 322                 if (!isatty(0))
 323                         goto finish;
 324                 /*
 325                  * TRANSLATORS: Make sure to include [Y] and [n] in your
 326                  * translation. The program will only accept English input
 327                  * at this point.
 328                  */
 329                 yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
 330                 if (starts_with(yesno, "N") || starts_with(yesno, "n"))
 331                         retval = -1;
 332                 goto finish;
 333         }
 334         if (!is_empty_or_missing_file(git_path_bisect_start())) {
 335                 retval = error(_(need_bad_and_good_revision_warning),
 336                                vocab_bad, vocab_good, vocab_bad, vocab_good);
 337         } else {
 338                 retval = error(_(need_bisect_start_warning),
 339                                vocab_good, vocab_bad, vocab_good, vocab_bad);
 340         }
 341
 342 finish:
 343         free((void *) good_glob);
 344         free((void *) bad_ref);
 345         return retval;
 346 }
 347
 348 static int get_terms(struct bisect_terms *terms)
 349 {
 350         struct strbuf str = STRBUF_INIT;
 351         FILE *fp = NULL;
 352         int res = 0;
 353
 354         fp = fopen(git_path_bisect_terms(), "r");
 355         if (!fp) {
 356                 res = -1;
 357                 goto finish;
 358         }
 359
 360         free_terms(terms);
 361         strbuf_getline_lf(&str, fp);
 362         terms->term_bad = strbuf_detach(&str, NULL);
 363         strbuf_getline_lf(&str, fp);
 364         terms->term_good = strbuf_detach(&str, NULL);
 365
 366 finish:
 367         if (fp)
 368                 fclose(fp);
 369         strbuf_release(&str);
 370         return res;
 371 }
 372
 373 static int bisect_terms(struct bisect_terms *terms, const char *option)
 374 {
 375         if (get_terms(terms))
 376                 return error(_("no terms defined"));
 377
 378         if (option == NULL) {
 379                 printf(_("Your current terms are %s for the old state\n"
 380                          "and %s for the new state.\n"),
 381                        terms->term_good, terms->term_bad);
 382                 return 0;
 383         }
 384         if (one_of(option, "--term-good", "--term-old", NULL))
 385                 printf("%s\n", terms->term_good);
 386         else if (one_of(option, "--term-bad", "--term-new", NULL))
 387                 printf("%s\n", terms->term_bad);
 388         else
 389                 return error(_("invalid argument %s for 'git bisect terms'.\n"
 390                                "Supported options are: "
 391                                "--term-good|--term-old and "
 392                                "--term-bad|--term-new."), option);
 393
 394         return 0;
 395 }
 396
 397 static int bisect_append_log_quoted(const char **argv)
 398 {
 399         int retval = 0;
 400         FILE *fp = fopen(git_path_bisect_log(), "a");
 401         struct strbuf orig_args = STRBUF_INIT;
 402
 403         if (!fp)
 404                 return -1;
 405
 406         if (fprintf(fp, "git bisect start") < 1) {
 407                 retval = -1;
 408                 goto finish;
 409         }
 410
 411         sq_quote_argv(&orig_args, argv);
 412         if (fprintf(fp, "%s\n", orig_args.buf) < 1)
 413                 retval = -1;
 414
 415 finish:
 416         fclose(fp);
 417         strbuf_release(&orig_args);
 418         return retval;
 419 }
 420
 421 static int bisect_start(struct bisect_terms *terms, int no_checkout,
 422                         const char **argv, int argc)
 423 {
 424         int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
 425         int flags, pathspec_pos, retval = 0;
 426         struct string_list revs = STRING_LIST_INIT_DUP;
 427         struct string_list states = STRING_LIST_INIT_DUP;
 428         struct strbuf start_head = STRBUF_INIT;
 429         struct strbuf bisect_names = STRBUF_INIT;
 430         struct object_id head_oid;
 431         struct object_id oid;
 432         const char *head;
 433
 434         if (is_bare_repository())
 435                 no_checkout = 1;
 436
 437         /*
 438          * Check for one bad and then some good revisions
 439          */
 440         for (i = 0; i < argc; i++) {
 441                 if (!strcmp(argv[i], "--")) {
 442                         has_double_dash = 1;
 443                         break;
 444                 }
 445         }
 446
 447         for (i = 0; i < argc; i++) {
 448                 const char *arg = argv[i];
 449                 if (!strcmp(argv[i], "--")) {
 450                         break;
 451                 } else if (!strcmp(arg, "--no-checkout")) {
 452                         no_checkout = 1;
 453                 } else if (!strcmp(arg, "--term-good") ||
 454                          !strcmp(arg, "--term-old")) {
 455                         must_write_terms = 1;
 456                         free((void *) terms->term_good);
 457                         terms->term_good = xstrdup(argv[++i]);
 458                 } else if (skip_prefix(arg, "--term-good=", &arg) ||
 459                            skip_prefix(arg, "--term-old=", &arg)) {
 460                         must_write_terms = 1;
 461                         free((void *) terms->term_good);
 462                         terms->term_good = xstrdup(arg);
 463                 } else if (!strcmp(arg, "--term-bad") ||
 464                          !strcmp(arg, "--term-new")) {
 465                         must_write_terms = 1;
 466                         free((void *) terms->term_bad);
 467                         terms->term_bad = xstrdup(argv[++i]);
 468                 } else if (skip_prefix(arg, "--term-bad=", &arg) ||
 469                            skip_prefix(arg, "--term-new=", &arg)) {
 470                         must_write_terms = 1;
 471                         free((void *) terms->term_bad);
 472                         terms->term_bad = xstrdup(arg);
 473                 } else if (starts_with(arg, "--") &&
 474                          !one_of(arg, "--term-good", "--term-bad", NULL)) {
 475                         return error(_("unrecognized option: '%s'"), arg);
 476                 } else {
 477                         char *commit_id = xstrfmt("%s^{commit}", arg);
 478                         if (get_oid(commit_id, &oid) && has_double_dash)
 479                                 die(_("'%s' does not appear to be a valid "
 480                                       "revision"), arg);
 481
 482                         string_list_append(&revs, oid_to_hex(&oid));
 483                         free(commit_id);
 484                 }
 485         }
 486         pathspec_pos = i;
 487
 488         /*
 489          * The user ran "git bisect start <sha1> <sha1>", hence did not
 490          * explicitly specify the terms, but we are already starting to
 491          * set references named with the default terms, and won't be able
 492          * to change afterwards.
 493          */
 494         if (revs.nr)
 495                 must_write_terms = 1;
 496         for (i = 0; i < revs.nr; i++) {
 497                 if (bad_seen) {
 498                         string_list_append(&states, terms->term_good);
 499                 } else {
 500                         bad_seen = 1;
 501                         string_list_append(&states, terms->term_bad);
 502                 }
 503         }
 504
 505         /*
 506          * Verify HEAD
 507          */
 508         head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
 509         if (!head)
 510                 if (get_oid("HEAD", &head_oid))
 511                         return error(_("bad HEAD - I need a HEAD"));
 512
 513         /*
 514          * Check if we are bisecting
 515          */
 516         if (!is_empty_or_missing_file(git_path_bisect_start())) {
 517                 /* Reset to the rev from where we started */
 518                 strbuf_read_file(&start_head, git_path_bisect_start(), 0);
 519                 strbuf_trim(&start_head);
 520                 if (!no_checkout) {
 521                         struct argv_array argv = ARGV_ARRAY_INIT;
 522
 523                         argv_array_pushl(&argv, "checkout", start_head.buf,
 524                                          "--", NULL);
 525                         if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
 526                                 retval = error(_("checking out '%s' failed."
 527                                                  " Try 'git bisect start "
 528                                                  "<valid-branch>'."),
 529                                                start_head.buf);
 530                                 goto finish;
 531                         }
 532                 }
 533         } else {
 534                 /* Get the rev from where we start. */
 535                 if (!get_oid(head, &head_oid) &&
 536                     !starts_with(head, "refs/heads/")) {
 537                         strbuf_reset(&start_head);
 538                         strbuf_addstr(&start_head, oid_to_hex(&head_oid));
 539                 } else if (!get_oid(head, &head_oid) &&
 540                            skip_prefix(head, "refs/heads/", &head)) {
 541                         /*
 542                          * This error message should only be triggered by
 543                          * cogito usage, and cogito users should understand
 544                          * it relates to cg-seek.
 545                          */
 546                         if (!is_empty_or_missing_file(git_path_head_name()))
 547                                 return error(_("won't bisect on cg-seek'ed tree"));
 548                         strbuf_addstr(&start_head, head);
 549                 } else {
 550                         return error(_("bad HEAD - strange symbolic ref"));
 551                 }
 552         }
 553
 554         /*
 555          * Get rid of any old bisect state.
 556          */
 557         if (bisect_clean_state())
 558                 return -1;
 559
 560         /*
 561          * In case of mistaken revs or checkout error, or signals received,
 562          * "bisect_auto_next" below may exit or misbehave.
 563          * We have to trap this to be able to clean up using
 564          * "bisect_clean_state".
 565          */
 566
 567         /*
 568          * Write new start state
 569          */
 570         write_file(git_path_bisect_start(), "%s\n", start_head.buf);
 571
 572         if (no_checkout) {
 573                 get_oid(start_head.buf, &oid);
 574                 if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
 575                                UPDATE_REFS_MSG_ON_ERR)) {
 576                         retval = -1;
 577                         goto finish;
 578                 }
 579         }
 580
 581         if (pathspec_pos < argc - 1)
 582                 sq_quote_argv(&bisect_names, argv + pathspec_pos);
 583         write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
 584
 585         for (i = 0; i < states.nr; i++)
 586                 if (bisect_write(states.items[i].string,
 587                                  revs.items[i].string, terms, 1)) {
 588                         retval = -1;
 589                         goto finish;
 590                 }
 591
 592         if (must_write_terms && write_terms(terms->term_bad,
 593                                             terms->term_good)) {
 594                 retval = -1;
 595                 goto finish;
 596         }
 597
 598         retval = bisect_append_log_quoted(argv);
 599         if (retval)
 600                 retval = -1;
 601
 602 finish:
 603         string_list_clear(&revs, 0);
 604         string_list_clear(&states, 0);
 605         strbuf_release(&start_head);
 606         strbuf_release(&bisect_names);
 607         return retval;
 608 }
 609
 610 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 611 {
 612         enum {
 613                 NEXT_ALL = 1,
 614                 WRITE_TERMS,
 615                 BISECT_CLEAN_STATE,
 616                 CHECK_EXPECTED_REVS,
 617                 BISECT_RESET,
 618                 BISECT_WRITE,
 619                 CHECK_AND_SET_TERMS,
 620                 BISECT_NEXT_CHECK,
 621                 BISECT_TERMS,
 622                 BISECT_START
 623         } cmdmode = 0;
 624         int no_checkout = 0, res = 0, nolog = 0;
 625         struct option options[] = {
 626                 OPT_CMDMODE(0, "next-all", &cmdmode,
 627                          N_("perform 'git bisect next'"), NEXT_ALL),
 628                 OPT_CMDMODE(0, "write-terms", &cmdmode,
 629                          N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 630                 OPT_CMDMODE(0, "bisect-clean-state", &cmdmode,
 631                          N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
 632                 OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
 633                          N_("check for expected revs"), CHECK_EXPECTED_REVS),
 634                 OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 635                          N_("reset the bisection state"), BISECT_RESET),
 636                 OPT_CMDMODE(0, "bisect-write", &cmdmode,
 637                          N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
 638                 OPT_CMDMODE(0, "check-and-set-terms", &cmdmode,
 639                          N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
 640                 OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
 641                          N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
 642                 OPT_CMDMODE(0, "bisect-terms", &cmdmode,
 643                          N_("print out the bisect terms"), BISECT_TERMS),
 644                 OPT_CMDMODE(0, "bisect-start", &cmdmode,
 645                          N_("start the bisect session"), BISECT_START),
 646                 OPT_BOOL(0, "no-checkout", &no_checkout,
 647                          N_("update BISECT_HEAD instead of checking out the current commit")),
 648                 OPT_BOOL(0, "no-log", &nolog,
 649                          N_("no log for BISECT_WRITE")),
 650                 OPT_END()
 651         };
 652         struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
 653
 654         argc = parse_options(argc, argv, prefix, options,
 655                              git_bisect_helper_usage,
 656                              PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
 657
 658         if (!cmdmode)
 659                 usage_with_options(git_bisect_helper_usage, options);
 660
 661         switch (cmdmode) {
 662         case NEXT_ALL:
 663                 return bisect_next_all(the_repository, prefix, no_checkout);
 664         case WRITE_TERMS:
 665                 if (argc != 2)
 666                         return error(_("--write-terms requires two arguments"));
 667                 return write_terms(argv[0], argv[1]);
 668         case BISECT_CLEAN_STATE:
 669                 if (argc != 0)
 670                         return error(_("--bisect-clean-state requires no arguments"));
 671                 return bisect_clean_state();
 672         case CHECK_EXPECTED_REVS:
 673                 check_expected_revs(argv, argc);
 674                 return 0;
 675         case BISECT_RESET:
 676                 if (argc > 1)
 677                         return error(_("--bisect-reset requires either no argument or a commit"));
 678                 return !!bisect_reset(argc ? argv[0] : NULL);
 679         case BISECT_WRITE:
 680                 if (argc != 4 && argc != 5)
 681                         return error(_("--bisect-write requires either 4 or 5 arguments"));
 682                 set_terms(&terms, argv[3], argv[2]);
 683                 res = bisect_write(argv[0], argv[1], &terms, nolog);
 684                 break;
 685         case CHECK_AND_SET_TERMS:
 686                 if (argc != 3)
 687                         return error(_("--check-and-set-terms requires 3 arguments"));
 688                 set_terms(&terms, argv[2], argv[1]);
 689                 res = check_and_set_terms(&terms, argv[0]);
 690                 break;
 691         case BISECT_NEXT_CHECK:
 692                 if (argc != 2 && argc != 3)
 693                         return error(_("--bisect-next-check requires 2 or 3 arguments"));
 694                 set_terms(&terms, argv[1], argv[0]);
 695                 res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
 696                 break;
 697         case BISECT_TERMS:
 698                 if (argc > 1)
 699                         return error(_("--bisect-terms requires 0 or 1 argument"));
 700                 res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
 701                 break;
 702         case BISECT_START:
 703                 set_terms(&terms, "bad", "good");
 704                 res = bisect_start(&terms, no_checkout, argv, argc);
 705                 break;
 706         default:
 707                 return error("BUG: unknown subcommand '%d'", cmdmode);
 708         }
 709         free_terms(&terms);
 710         return !!res;
 711 }