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_log, "BISECT_LOG")
  17 static GIT_PATH_FUNC(git_path_head_name, "head-name")
  18 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
  19
  20 static const char * const git_bisect_helper_usage[] = {
  21         N_("git bisect--helper --next-all [--no-checkout]"),
  22         N_("git bisect--helper --write-terms <bad_term> <good_term>"),
  23         N_("git bisect--helper --bisect-clean-state"),
  24         N_("git bisect--helper --bisect-reset [<commit>]"),
  25         N_("git bisect--helper --bisect-write [--no-log] <state> <revision> <good_term> <bad_term>"),
  26         N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
  27         N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
  28         N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
  29         N_("git bisect--helper --bisect-start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
  30                                              "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
  31         NULL
  32 };
  33
  34 struct bisect_terms {
  35         char *term_good;
  36         char *term_bad;
  37 };
  38
  39 static void free_terms(struct bisect_terms *terms)
  40 {
  41         FREE_AND_NULL(terms->term_good);
  42         FREE_AND_NULL(terms->term_bad);
  43 }
  44
  45 static void set_terms(struct bisect_terms *terms, const char *bad,
  46                       const char *good)
  47 {
  48         free((void *)terms->term_good);
  49         terms->term_good = xstrdup(good);
  50         free((void *)terms->term_bad);
  51         terms->term_bad = xstrdup(bad);
  52 }
  53
  54 static const char vocab_bad[] = "bad|new";
  55 static const char vocab_good[] = "good|old";
  56
  57 /*
  58  * Check whether the string `term` belongs to the set of strings
  59  * included in the variable arguments.
  60  */
  61 LAST_ARG_MUST_BE_NULL
  62 static int one_of(const char *term, ...)
  63 {
  64         int res = 0;
  65         va_list matches;
  66         const char *match;
  67
  68         va_start(matches, term);
  69         while (!res && (match = va_arg(matches, const char *)))
  70                 res = !strcmp(term, match);
  71         va_end(matches);
  72
  73         return res;
  74 }
  75
  76 static int check_term_format(const char *term, const char *orig_term)
  77 {
  78         int res;
  79         char *new_term = xstrfmt("refs/bisect/%s", term);
  80
  81         res = check_refname_format(new_term, 0);
  82         free(new_term);
  83
  84         if (res)
  85                 return error(_("'%s' is not a valid term"), term);
  86
  87         if (one_of(term, "help", "start", "skip", "next", "reset",
  88                         "visualize", "view", "replay", "log", "run", "terms", NULL))
  89                 return error(_("can't use the builtin command '%s' as a term"), term);
  90
  91         /*
  92          * In theory, nothing prevents swapping completely good and bad,
  93          * but this situation could be confusing and hasn't been tested
  94          * enough. Forbid it for now.
  95          */
  96
  97         if ((strcmp(orig_term, "bad") && one_of(term, "bad", "new", NULL)) ||
  98                  (strcmp(orig_term, "good") && one_of(term, "good", "old", NULL)))
  99                 return error(_("can't change the meaning of the term '%s'"), term);
 100
 101         return 0;
 102 }
 103
 104 static int write_terms(const char *bad, const char *good)
 105 {
 106         FILE *fp = NULL;
 107         int res;
 108
 109         if (!strcmp(bad, good))
 110                 return error(_("please use two different terms"));
 111
 112         if (check_term_format(bad, "bad") || check_term_format(good, "good"))
 113                 return -1;
 114
 115         fp = fopen(git_path_bisect_terms(), "w");
 116         if (!fp)
 117                 return error_errno(_("could not open the file BISECT_TERMS"));
 118
 119         res = fprintf(fp, "%s\n%s\n", bad, good);
 120         res |= fclose(fp);
 121         return (res < 0) ? -1 : 0;
 122 }
 123
 124 static int is_expected_rev(const char *expected_hex)
 125 {
 126         struct strbuf actual_hex = STRBUF_INIT;
 127         int res = 0;
 128         if (strbuf_read_file(&actual_hex, git_path_bisect_expected_rev(), 0) >= 40) {
 129                 strbuf_trim(&actual_hex);
 130                 res = !strcmp(actual_hex.buf, expected_hex);
 131         }
 132         strbuf_release(&actual_hex);
 133         return res;
 134 }
 135
 136 static void check_expected_revs(const char **revs, int rev_nr)
 137 {
 138         int i;
 139
 140         for (i = 0; i < rev_nr; i++) {
 141                 if (!is_expected_rev(revs[i])) {
 142                         unlink_or_warn(git_path_bisect_ancestors_ok());
 143                         unlink_or_warn(git_path_bisect_expected_rev());
 144                 }
 145         }
 146 }
 147
 148 static int bisect_reset(const char *commit)
 149 {
 150         struct strbuf branch = STRBUF_INIT;
 151
 152         if (!commit) {
 153                 if (strbuf_read_file(&branch, git_path_bisect_start(), 0) < 1) {
 154                         printf(_("We are not bisecting.\n"));
 155                         return 0;
 156                 }
 157                 strbuf_rtrim(&branch);
 158         } else {
 159                 struct object_id oid;
 160
 161                 if (get_oid_commit(commit, &oid))
 162                         return error(_("'%s' is not a valid commit"), commit);
 163                 strbuf_addstr(&branch, commit);
 164         }
 165
 166         if (!ref_exists("BISECT_HEAD")) {
 167                 struct argv_array argv = ARGV_ARRAY_INIT;
 168
 169                 argv_array_pushl(&argv, "checkout", branch.buf, "--", NULL);
 170                 if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
 171                         error(_("could not check out original"
 172                                 " HEAD '%s'. Try 'git bisect"
 173                                 " reset <commit>'."), branch.buf);
 174                         strbuf_release(&branch);
 175                         argv_array_clear(&argv);
 176                         return -1;
 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 res = 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                 res = error(_("Bad bisect_write argument: %s"), state);
 216                 goto finish;
 217         }
 218
 219         if (get_oid(rev, &oid)) {
 220                 res = 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                 res = -1;
 227                 goto finish;
 228         }
 229
 230         fp = fopen(git_path_bisect_log(), "a");
 231         if (!fp) {
 232                 res = 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 res;
 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 decide_next(const struct bisect_terms *terms,
 294                        const char *current_term, int missing_good,
 295                        int missing_bad)
 296 {
 297         if (!missing_good && !missing_bad)
 298                 return 0;
 299         if (!current_term)
 300                 return -1;
 301
 302         if (missing_good && !missing_bad &&
 303             !strcmp(current_term, terms->term_good)) {
 304                 char *yesno;
 305                 /*
 306                  * have bad (or new) but not good (or old). We could bisect
 307                  * although this is less optimum.
 308                  */
 309                 warning(_("bisecting only with a %s commit"), terms->term_bad);
 310                 if (!isatty(0))
 311                         return 0;
 312                 /*
 313                  * TRANSLATORS: Make sure to include [Y] and [n] in your
 314                  * translation. The program will only accept English input
 315                  * at this point.
 316                  */
 317                 yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
 318                 if (starts_with(yesno, "N") || starts_with(yesno, "n"))
 319                         return -1;
 320                 return 0;
 321         }
 322
 323         if (!is_empty_or_missing_file(git_path_bisect_start()))
 324                 return error(_(need_bad_and_good_revision_warning),
 325                              vocab_bad, vocab_good, vocab_bad, vocab_good);
 326         else
 327                 return error(_(need_bisect_start_warning),
 328                              vocab_good, vocab_bad, vocab_good, vocab_bad);
 329 }
 330
 331 static int bisect_next_check(const struct bisect_terms *terms,
 332                              const char *current_term)
 333 {
 334         int missing_good = 1, missing_bad = 1;
 335         char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
 336         char *good_glob = xstrfmt("%s-*", terms->term_good);
 337
 338         if (ref_exists(bad_ref))
 339                 missing_bad = 0;
 340
 341         for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
 342                              (void *) &missing_good);
 343
 344         free(good_glob);
 345         free(bad_ref);
 346
 347         return decide_next(terms, current_term, missing_good, missing_bad);
 348 }
 349
 350 static int get_terms(struct bisect_terms *terms)
 351 {
 352         struct strbuf str = STRBUF_INIT;
 353         FILE *fp = NULL;
 354         int res = 0;
 355
 356         fp = fopen(git_path_bisect_terms(), "r");
 357         if (!fp) {
 358                 res = -1;
 359                 goto finish;
 360         }
 361
 362         free_terms(terms);
 363         strbuf_getline_lf(&str, fp);
 364         terms->term_bad = strbuf_detach(&str, NULL);
 365         strbuf_getline_lf(&str, fp);
 366         terms->term_good = strbuf_detach(&str, NULL);
 367
 368 finish:
 369         if (fp)
 370                 fclose(fp);
 371         strbuf_release(&str);
 372         return res;
 373 }
 374
 375 static int bisect_terms(struct bisect_terms *terms, const char *option)
 376 {
 377         if (get_terms(terms))
 378                 return error(_("no terms defined"));
 379
 380         if (option == NULL) {
 381                 printf(_("Your current terms are %s for the old state\n"
 382                          "and %s for the new state.\n"),
 383                        terms->term_good, terms->term_bad);
 384                 return 0;
 385         }
 386         if (one_of(option, "--term-good", "--term-old", NULL))
 387                 printf("%s\n", terms->term_good);
 388         else if (one_of(option, "--term-bad", "--term-new", NULL))
 389                 printf("%s\n", terms->term_bad);
 390         else
 391                 return error(_("invalid argument %s for 'git bisect terms'.\n"
 392                                "Supported options are: "
 393                                "--term-good|--term-old and "
 394                                "--term-bad|--term-new."), option);
 395
 396         return 0;
 397 }
 398
 399 static int bisect_append_log_quoted(const char **argv)
 400 {
 401         int res = 0;
 402         FILE *fp = fopen(git_path_bisect_log(), "a");
 403         struct strbuf orig_args = STRBUF_INIT;
 404
 405         if (!fp)
 406                 return -1;
 407
 408         if (fprintf(fp, "git bisect start") < 1) {
 409                 res = -1;
 410                 goto finish;
 411         }
 412
 413         sq_quote_argv(&orig_args, argv);
 414         if (fprintf(fp, "%s\n", orig_args.buf) < 1)
 415                 res = -1;
 416
 417 finish:
 418         fclose(fp);
 419         strbuf_release(&orig_args);
 420         return res;
 421 }
 422
 423 static int bisect_start(struct bisect_terms *terms, int no_checkout,
 424                         const char **argv, int argc)
 425 {
 426         int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
 427         int flags, pathspec_pos, res = 0;
 428         struct string_list revs = STRING_LIST_INIT_DUP;
 429         struct string_list states = STRING_LIST_INIT_DUP;
 430         struct strbuf start_head = STRBUF_INIT;
 431         struct strbuf bisect_names = STRBUF_INIT;
 432         struct object_id head_oid;
 433         struct object_id oid;
 434         const char *head;
 435
 436         if (is_bare_repository())
 437                 no_checkout = 1;
 438
 439         /*
 440          * Check for one bad and then some good revisions
 441          */
 442         for (i = 0; i < argc; i++) {
 443                 if (!strcmp(argv[i], "--")) {
 444                         has_double_dash = 1;
 445                         break;
 446                 }
 447         }
 448
 449         for (i = 0; i < argc; i++) {
 450                 const char *arg = argv[i];
 451                 if (!strcmp(argv[i], "--")) {
 452                         break;
 453                 } else if (!strcmp(arg, "--no-checkout")) {
 454                         no_checkout = 1;
 455                 } else if (!strcmp(arg, "--term-good") ||
 456                          !strcmp(arg, "--term-old")) {
 457                         i++;
 458                         if (argc <= i)
 459                                 return error(_("'' is not a valid term"));
 460                         must_write_terms = 1;
 461                         free((void *) terms->term_good);
 462                         terms->term_good = xstrdup(argv[i]);
 463                 } else if (skip_prefix(arg, "--term-good=", &arg) ||
 464                            skip_prefix(arg, "--term-old=", &arg)) {
 465                         must_write_terms = 1;
 466                         free((void *) terms->term_good);
 467                         terms->term_good = xstrdup(arg);
 468                 } else if (!strcmp(arg, "--term-bad") ||
 469                          !strcmp(arg, "--term-new")) {
 470                         i++;
 471                         if (argc <= i)
 472                                 return error(_("'' is not a valid term"));
 473                         must_write_terms = 1;
 474                         free((void *) terms->term_bad);
 475                         terms->term_bad = xstrdup(argv[i]);
 476                 } else if (skip_prefix(arg, "--term-bad=", &arg) ||
 477                            skip_prefix(arg, "--term-new=", &arg)) {
 478                         must_write_terms = 1;
 479                         free((void *) terms->term_bad);
 480                         terms->term_bad = xstrdup(arg);
 481                 } else if (starts_with(arg, "--")) {
 482                         return error(_("unrecognized option: '%s'"), arg);
 483                 } else {
 484                         char *commit_id = xstrfmt("%s^{commit}", arg);
 485                         if (get_oid(commit_id, &oid) && has_double_dash)
 486                                 die(_("'%s' does not appear to be a valid "
 487                                       "revision"), arg);
 488
 489                         string_list_append(&revs, oid_to_hex(&oid));
 490                         free(commit_id);
 491                 }
 492         }
 493         pathspec_pos = i;
 494
 495         /*
 496          * The user ran "git bisect start <sha1> <sha1>", hence did not
 497          * explicitly specify the terms, but we are already starting to
 498          * set references named with the default terms, and won't be able
 499          * to change afterwards.
 500          */
 501         if (revs.nr)
 502                 must_write_terms = 1;
 503         for (i = 0; i < revs.nr; i++) {
 504                 if (bad_seen) {
 505                         string_list_append(&states, terms->term_good);
 506                 } else {
 507                         bad_seen = 1;
 508                         string_list_append(&states, terms->term_bad);
 509                 }
 510         }
 511
 512         /*
 513          * Verify HEAD
 514          */
 515         head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
 516         if (!head)
 517                 if (get_oid("HEAD", &head_oid))
 518                         return error(_("bad HEAD - I need a HEAD"));
 519
 520         /*
 521          * Check if we are bisecting
 522          */
 523         if (!is_empty_or_missing_file(git_path_bisect_start())) {
 524                 /* Reset to the rev from where we started */
 525                 strbuf_read_file(&start_head, git_path_bisect_start(), 0);
 526                 strbuf_trim(&start_head);
 527                 if (!no_checkout) {
 528                         struct argv_array argv = ARGV_ARRAY_INIT;
 529
 530                         argv_array_pushl(&argv, "checkout", start_head.buf,
 531                                          "--", NULL);
 532                         if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
 533                                 res = error(_("checking out '%s' failed."
 534                                                  " Try 'git bisect start "
 535                                                  "<valid-branch>'."),
 536                                                start_head.buf);
 537                                 goto finish;
 538                         }
 539                 }
 540         } else {
 541                 /* Get the rev from where we start. */
 542                 if (!get_oid(head, &head_oid) &&
 543                     !starts_with(head, "refs/heads/")) {
 544                         strbuf_reset(&start_head);
 545                         strbuf_addstr(&start_head, oid_to_hex(&head_oid));
 546                 } else if (!get_oid(head, &head_oid) &&
 547                            skip_prefix(head, "refs/heads/", &head)) {
 548                         /*
 549                          * This error message should only be triggered by
 550                          * cogito usage, and cogito users should understand
 551                          * it relates to cg-seek.
 552                          */
 553                         if (!is_empty_or_missing_file(git_path_head_name()))
 554                                 return error(_("won't bisect on cg-seek'ed tree"));
 555                         strbuf_addstr(&start_head, head);
 556                 } else {
 557                         return error(_("bad HEAD - strange symbolic ref"));
 558                 }
 559         }
 560
 561         /*
 562          * Get rid of any old bisect state.
 563          */
 564         if (bisect_clean_state())
 565                 return -1;
 566
 567         /*
 568          * In case of mistaken revs or checkout error, or signals received,
 569          * "bisect_auto_next" below may exit or misbehave.
 570          * We have to trap this to be able to clean up using
 571          * "bisect_clean_state".
 572          */
 573
 574         /*
 575          * Write new start state
 576          */
 577         write_file(git_path_bisect_start(), "%s\n", start_head.buf);
 578
 579         if (no_checkout) {
 580                 if (get_oid(start_head.buf, &oid) < 0) {
 581                         res = error(_("invalid ref: '%s'"), start_head.buf);
 582                         goto finish;
 583                 }
 584                 if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
 585                                UPDATE_REFS_MSG_ON_ERR)) {
 586                         res = -1;
 587                         goto finish;
 588                 }
 589         }
 590
 591         if (pathspec_pos < argc - 1)
 592                 sq_quote_argv(&bisect_names, argv + pathspec_pos);
 593         write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
 594
 595         for (i = 0; i < states.nr; i++)
 596                 if (bisect_write(states.items[i].string,
 597                                  revs.items[i].string, terms, 1)) {
 598                         res = -1;
 599                         goto finish;
 600                 }
 601
 602         if (must_write_terms && write_terms(terms->term_bad,
 603                                             terms->term_good)) {
 604                 res = -1;
 605                 goto finish;
 606         }
 607
 608         res = bisect_append_log_quoted(argv);
 609         if (res)
 610                 res = -1;
 611
 612 finish:
 613         string_list_clear(&revs, 0);
 614         string_list_clear(&states, 0);
 615         strbuf_release(&start_head);
 616         strbuf_release(&bisect_names);
 617         return res;
 618 }
 619
 620 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 621 {
 622         enum {
 623                 NEXT_ALL = 1,
 624                 WRITE_TERMS,
 625                 BISECT_CLEAN_STATE,
 626                 CHECK_EXPECTED_REVS,
 627                 BISECT_RESET,
 628                 BISECT_WRITE,
 629                 CHECK_AND_SET_TERMS,
 630                 BISECT_NEXT_CHECK,
 631                 BISECT_TERMS,
 632                 BISECT_START
 633         } cmdmode = 0;
 634         int no_checkout = 0, res = 0, nolog = 0;
 635         struct option options[] = {
 636                 OPT_CMDMODE(0, "next-all", &cmdmode,
 637                          N_("perform 'git bisect next'"), NEXT_ALL),
 638                 OPT_CMDMODE(0, "write-terms", &cmdmode,
 639                          N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 640                 OPT_CMDMODE(0, "bisect-clean-state", &cmdmode,
 641                          N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
 642                 OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
 643                          N_("check for expected revs"), CHECK_EXPECTED_REVS),
 644                 OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 645                          N_("reset the bisection state"), BISECT_RESET),
 646                 OPT_CMDMODE(0, "bisect-write", &cmdmode,
 647                          N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
 648                 OPT_CMDMODE(0, "check-and-set-terms", &cmdmode,
 649                          N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
 650                 OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
 651                          N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
 652                 OPT_CMDMODE(0, "bisect-terms", &cmdmode,
 653                          N_("print out the bisect terms"), BISECT_TERMS),
 654                 OPT_CMDMODE(0, "bisect-start", &cmdmode,
 655                          N_("start the bisect session"), BISECT_START),
 656                 OPT_BOOL(0, "no-checkout", &no_checkout,
 657                          N_("update BISECT_HEAD instead of checking out the current commit")),
 658                 OPT_BOOL(0, "no-log", &nolog,
 659                          N_("no log for BISECT_WRITE")),
 660                 OPT_END()
 661         };
 662         struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
 663
 664         argc = parse_options(argc, argv, prefix, options,
 665                              git_bisect_helper_usage,
 666                              PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
 667
 668         if (!cmdmode)
 669                 usage_with_options(git_bisect_helper_usage, options);
 670
 671         switch (cmdmode) {
 672         case NEXT_ALL:
 673                 res = bisect_next_all(the_repository, prefix, no_checkout);
 674                 break;
 675         case WRITE_TERMS:
 676                 if (argc != 2)
 677                         return error(_("--write-terms requires two arguments"));
 678                 return write_terms(argv[0], argv[1]);
 679         case BISECT_CLEAN_STATE:
 680                 if (argc != 0)
 681                         return error(_("--bisect-clean-state requires no arguments"));
 682                 return bisect_clean_state();
 683         case CHECK_EXPECTED_REVS:
 684                 check_expected_revs(argv, argc);
 685                 return 0;
 686         case BISECT_RESET:
 687                 if (argc > 1)
 688                         return error(_("--bisect-reset requires either no argument or a commit"));
 689                 return !!bisect_reset(argc ? argv[0] : NULL);
 690         case BISECT_WRITE:
 691                 if (argc != 4 && argc != 5)
 692                         return error(_("--bisect-write requires either 4 or 5 arguments"));
 693                 set_terms(&terms, argv[3], argv[2]);
 694                 res = bisect_write(argv[0], argv[1], &terms, nolog);
 695                 break;
 696         case CHECK_AND_SET_TERMS:
 697                 if (argc != 3)
 698                         return error(_("--check-and-set-terms requires 3 arguments"));
 699                 set_terms(&terms, argv[2], argv[1]);
 700                 res = check_and_set_terms(&terms, argv[0]);
 701                 break;
 702         case BISECT_NEXT_CHECK:
 703                 if (argc != 2 && argc != 3)
 704                         return error(_("--bisect-next-check requires 2 or 3 arguments"));
 705                 set_terms(&terms, argv[1], argv[0]);
 706                 res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
 707                 break;
 708         case BISECT_TERMS:
 709                 if (argc > 1)
 710                         return error(_("--bisect-terms requires 0 or 1 argument"));
 711                 res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
 712                 break;
 713         case BISECT_START:
 714                 set_terms(&terms, "bad", "good");
 715                 res = bisect_start(&terms, no_checkout, argv, argc);
 716                 break;
 717         default:
 718                 return error("BUG: unknown subcommand '%d'", cmdmode);
 719         }
 720         free_terms(&terms);
 721
 722         /*
 723          * Handle early success
 724          * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
 725          */
 726         if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE)
 727                 res = BISECT_OK;
 728
 729         return abs(res);
 730 }