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                         error(_("could not check out original"
 173                                 " HEAD '%s'. Try 'git bisect"
 174                                 " reset <commit>'."), branch.buf);
 175                         strbuf_release(&branch);
 176                         argv_array_clear(&argv);
 177                         return -1;
 178                 }
 179                 argv_array_clear(&argv);
 180         }
 181
 182         strbuf_release(&branch);
 183         return bisect_clean_state();
 184 }
 185
 186 static void log_commit(FILE *fp, char *fmt, const char *state,
 187                        struct commit *commit)
 188 {
 189         struct pretty_print_context pp = {0};
 190         struct strbuf commit_msg = STRBUF_INIT;
 191         char *label = xstrfmt(fmt, state);
 192
 193         format_commit_message(commit, "%s", &commit_msg, &pp);
 194
 195         fprintf(fp, "# %s: [%s] %s\n", label, oid_to_hex(&commit->object.oid),
 196                 commit_msg.buf);
 197
 198         strbuf_release(&commit_msg);
 199         free(label);
 200 }
 201
 202 static int bisect_write(const char *state, const char *rev,
 203                         const struct bisect_terms *terms, int nolog)
 204 {
 205         struct strbuf tag = STRBUF_INIT;
 206         struct object_id oid;
 207         struct commit *commit;
 208         FILE *fp = NULL;
 209         int res = 0;
 210
 211         if (!strcmp(state, terms->term_bad)) {
 212                 strbuf_addf(&tag, "refs/bisect/%s", state);
 213         } else if (one_of(state, terms->term_good, "skip", NULL)) {
 214                 strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
 215         } else {
 216                 res = error(_("Bad bisect_write argument: %s"), state);
 217                 goto finish;
 218         }
 219
 220         if (get_oid(rev, &oid)) {
 221                 res = error(_("couldn't get the oid of the rev '%s'"), rev);
 222                 goto finish;
 223         }
 224
 225         if (update_ref(NULL, tag.buf, &oid, NULL, 0,
 226                        UPDATE_REFS_MSG_ON_ERR)) {
 227                 res = -1;
 228                 goto finish;
 229         }
 230
 231         fp = fopen(git_path_bisect_log(), "a");
 232         if (!fp) {
 233                 res = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
 234                 goto finish;
 235         }
 236
 237         commit = lookup_commit_reference(the_repository, &oid);
 238         log_commit(fp, "%s", state, commit);
 239
 240         if (!nolog)
 241                 fprintf(fp, "git bisect %s %s\n", state, rev);
 242
 243 finish:
 244         if (fp)
 245                 fclose(fp);
 246         strbuf_release(&tag);
 247         return res;
 248 }
 249
 250 static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
 251 {
 252         int has_term_file = !is_empty_or_missing_file(git_path_bisect_terms());
 253
 254         if (one_of(cmd, "skip", "start", "terms", NULL))
 255                 return 0;
 256
 257         if (has_term_file && strcmp(cmd, terms->term_bad) &&
 258             strcmp(cmd, terms->term_good))
 259                 return error(_("Invalid command: you're currently in a "
 260                                 "%s/%s bisect"), terms->term_bad,
 261                                 terms->term_good);
 262
 263         if (!has_term_file) {
 264                 if (one_of(cmd, "bad", "good", NULL)) {
 265                         set_terms(terms, "bad", "good");
 266                         return write_terms(terms->term_bad, terms->term_good);
 267                 }
 268                 if (one_of(cmd, "new", "old", NULL)) {
 269                         set_terms(terms, "new", "old");
 270                         return write_terms(terms->term_bad, terms->term_good);
 271                 }
 272         }
 273
 274         return 0;
 275 }
 276
 277 static int mark_good(const char *refname, const struct object_id *oid,
 278                      int flag, void *cb_data)
 279 {
 280         int *m_good = (int *)cb_data;
 281         *m_good = 0;
 282         return 1;
 283 }
 284
 285 static const char need_bad_and_good_revision_warning[] =
 286         N_("You need to give me at least one %s and %s revision.\n"
 287            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 288
 289 static const char need_bisect_start_warning[] =
 290         N_("You need to start by \"git bisect start\".\n"
 291            "You then need to give me at least one %s and %s revision.\n"
 292            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 293
 294 static int decide_next(const struct bisect_terms *terms,
 295                        const char *current_term, int missing_good,
 296                        int missing_bad)
 297 {
 298         if (!missing_good && !missing_bad)
 299                 return 0;
 300         if (!current_term)
 301                 return -1;
 302
 303         if (missing_good && !missing_bad &&
 304             !strcmp(current_term, terms->term_good)) {
 305                 char *yesno;
 306                 /*
 307                  * have bad (or new) but not good (or old). We could bisect
 308                  * although this is less optimum.
 309                  */
 310                 warning(_("bisecting only with a %s commit"), terms->term_bad);
 311                 if (!isatty(0))
 312                         return 0;
 313                 /*
 314                  * TRANSLATORS: Make sure to include [Y] and [n] in your
 315                  * translation. The program will only accept English input
 316                  * at this point.
 317                  */
 318                 yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
 319                 if (starts_with(yesno, "N") || starts_with(yesno, "n"))
 320                         return -1;
 321                 return 0;
 322         }
 323
 324         if (!is_empty_or_missing_file(git_path_bisect_start()))
 325                 return error(_(need_bad_and_good_revision_warning),
 326                              vocab_bad, vocab_good, vocab_bad, vocab_good);
 327         else
 328                 return error(_(need_bisect_start_warning),
 329                              vocab_good, vocab_bad, vocab_good, vocab_bad);
 330 }
 331
 332 static int bisect_next_check(const struct bisect_terms *terms,
 333                              const char *current_term)
 334 {
 335         int missing_good = 1, missing_bad = 1;
 336         char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
 337         char *good_glob = xstrfmt("%s-*", terms->term_good);
 338
 339         if (ref_exists(bad_ref))
 340                 missing_bad = 0;
 341
 342         for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
 343                              (void *) &missing_good);
 344
 345         free(good_glob);
 346         free(bad_ref);
 347
 348         return decide_next(terms, current_term, missing_good, missing_bad);
 349 }
 350
 351 static int get_terms(struct bisect_terms *terms)
 352 {
 353         struct strbuf str = STRBUF_INIT;
 354         FILE *fp = NULL;
 355         int res = 0;
 356
 357         fp = fopen(git_path_bisect_terms(), "r");
 358         if (!fp) {
 359                 res = -1;
 360                 goto finish;
 361         }
 362
 363         free_terms(terms);
 364         strbuf_getline_lf(&str, fp);
 365         terms->term_bad = strbuf_detach(&str, NULL);
 366         strbuf_getline_lf(&str, fp);
 367         terms->term_good = strbuf_detach(&str, NULL);
 368
 369 finish:
 370         if (fp)
 371                 fclose(fp);
 372         strbuf_release(&str);
 373         return res;
 374 }
 375
 376 static int bisect_terms(struct bisect_terms *terms, const char *option)
 377 {
 378         if (get_terms(terms))
 379                 return error(_("no terms defined"));
 380
 381         if (option == NULL) {
 382                 printf(_("Your current terms are %s for the old state\n"
 383                          "and %s for the new state.\n"),
 384                        terms->term_good, terms->term_bad);
 385                 return 0;
 386         }
 387         if (one_of(option, "--term-good", "--term-old", NULL))
 388                 printf("%s\n", terms->term_good);
 389         else if (one_of(option, "--term-bad", "--term-new", NULL))
 390                 printf("%s\n", terms->term_bad);
 391         else
 392                 return error(_("invalid argument %s for 'git bisect terms'.\n"
 393                                "Supported options are: "
 394                                "--term-good|--term-old and "
 395                                "--term-bad|--term-new."), option);
 396
 397         return 0;
 398 }
 399
 400 static int bisect_append_log_quoted(const char **argv)
 401 {
 402         int res = 0;
 403         FILE *fp = fopen(git_path_bisect_log(), "a");
 404         struct strbuf orig_args = STRBUF_INIT;
 405
 406         if (!fp)
 407                 return -1;
 408
 409         if (fprintf(fp, "git bisect start") < 1) {
 410                 res = -1;
 411                 goto finish;
 412         }
 413
 414         sq_quote_argv(&orig_args, argv);
 415         if (fprintf(fp, "%s\n", orig_args.buf) < 1)
 416                 res = -1;
 417
 418 finish:
 419         fclose(fp);
 420         strbuf_release(&orig_args);
 421         return res;
 422 }
 423
 424 static int bisect_start(struct bisect_terms *terms, int no_checkout,
 425                         const char **argv, int argc)
 426 {
 427         int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
 428         int flags, pathspec_pos, res = 0;
 429         struct string_list revs = STRING_LIST_INIT_DUP;
 430         struct string_list states = STRING_LIST_INIT_DUP;
 431         struct strbuf start_head = STRBUF_INIT;
 432         struct strbuf bisect_names = STRBUF_INIT;
 433         struct object_id head_oid;
 434         struct object_id oid;
 435         const char *head;
 436
 437         if (is_bare_repository())
 438                 no_checkout = 1;
 439
 440         /*
 441          * Check for one bad and then some good revisions
 442          */
 443         for (i = 0; i < argc; i++) {
 444                 if (!strcmp(argv[i], "--")) {
 445                         has_double_dash = 1;
 446                         break;
 447                 }
 448         }
 449
 450         for (i = 0; i < argc; i++) {
 451                 const char *arg = argv[i];
 452                 if (!strcmp(argv[i], "--")) {
 453                         break;
 454                 } else if (!strcmp(arg, "--no-checkout")) {
 455                         no_checkout = 1;
 456                 } else if (!strcmp(arg, "--term-good") ||
 457                          !strcmp(arg, "--term-old")) {
 458                         must_write_terms = 1;
 459                         free((void *) terms->term_good);
 460                         terms->term_good = xstrdup(argv[++i]);
 461                 } else if (skip_prefix(arg, "--term-good=", &arg) ||
 462                            skip_prefix(arg, "--term-old=", &arg)) {
 463                         must_write_terms = 1;
 464                         free((void *) terms->term_good);
 465                         terms->term_good = xstrdup(arg);
 466                 } else if (!strcmp(arg, "--term-bad") ||
 467                          !strcmp(arg, "--term-new")) {
 468                         must_write_terms = 1;
 469                         free((void *) terms->term_bad);
 470                         terms->term_bad = xstrdup(argv[++i]);
 471                 } else if (skip_prefix(arg, "--term-bad=", &arg) ||
 472                            skip_prefix(arg, "--term-new=", &arg)) {
 473                         must_write_terms = 1;
 474                         free((void *) terms->term_bad);
 475                         terms->term_bad = xstrdup(arg);
 476                 } else if (starts_with(arg, "--") &&
 477                          !one_of(arg, "--term-good", "--term-bad", NULL)) {
 478                         return error(_("unrecognized option: '%s'"), arg);
 479                 } else {
 480                         char *commit_id = xstrfmt("%s^{commit}", arg);
 481                         if (get_oid(commit_id, &oid) && has_double_dash)
 482                                 die(_("'%s' does not appear to be a valid "
 483                                       "revision"), arg);
 484
 485                         string_list_append(&revs, oid_to_hex(&oid));
 486                         free(commit_id);
 487                 }
 488         }
 489         pathspec_pos = i;
 490
 491         /*
 492          * The user ran "git bisect start <sha1> <sha1>", hence did not
 493          * explicitly specify the terms, but we are already starting to
 494          * set references named with the default terms, and won't be able
 495          * to change afterwards.
 496          */
 497         if (revs.nr)
 498                 must_write_terms = 1;
 499         for (i = 0; i < revs.nr; i++) {
 500                 if (bad_seen) {
 501                         string_list_append(&states, terms->term_good);
 502                 } else {
 503                         bad_seen = 1;
 504                         string_list_append(&states, terms->term_bad);
 505                 }
 506         }
 507
 508         /*
 509          * Verify HEAD
 510          */
 511         head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
 512         if (!head)
 513                 if (get_oid("HEAD", &head_oid))
 514                         return error(_("bad HEAD - I need a HEAD"));
 515
 516         /*
 517          * Check if we are bisecting
 518          */
 519         if (!is_empty_or_missing_file(git_path_bisect_start())) {
 520                 /* Reset to the rev from where we started */
 521                 strbuf_read_file(&start_head, git_path_bisect_start(), 0);
 522                 strbuf_trim(&start_head);
 523                 if (!no_checkout) {
 524                         struct argv_array argv = ARGV_ARRAY_INIT;
 525
 526                         argv_array_pushl(&argv, "checkout", start_head.buf,
 527                                          "--", NULL);
 528                         if (run_command_v_opt(argv.argv, RUN_GIT_CMD)) {
 529                                 res = error(_("checking out '%s' failed."
 530                                                  " Try 'git bisect start "
 531                                                  "<valid-branch>'."),
 532                                                start_head.buf);
 533                                 goto finish;
 534                         }
 535                 }
 536         } else {
 537                 /* Get the rev from where we start. */
 538                 if (!get_oid(head, &head_oid) &&
 539                     !starts_with(head, "refs/heads/")) {
 540                         strbuf_reset(&start_head);
 541                         strbuf_addstr(&start_head, oid_to_hex(&head_oid));
 542                 } else if (!get_oid(head, &head_oid) &&
 543                            skip_prefix(head, "refs/heads/", &head)) {
 544                         /*
 545                          * This error message should only be triggered by
 546                          * cogito usage, and cogito users should understand
 547                          * it relates to cg-seek.
 548                          */
 549                         if (!is_empty_or_missing_file(git_path_head_name()))
 550                                 return error(_("won't bisect on cg-seek'ed tree"));
 551                         strbuf_addstr(&start_head, head);
 552                 } else {
 553                         return error(_("bad HEAD - strange symbolic ref"));
 554                 }
 555         }
 556
 557         /*
 558          * Get rid of any old bisect state.
 559          */
 560         if (bisect_clean_state())
 561                 return -1;
 562
 563         /*
 564          * In case of mistaken revs or checkout error, or signals received,
 565          * "bisect_auto_next" below may exit or misbehave.
 566          * We have to trap this to be able to clean up using
 567          * "bisect_clean_state".
 568          */
 569
 570         /*
 571          * Write new start state
 572          */
 573         write_file(git_path_bisect_start(), "%s\n", start_head.buf);
 574
 575         if (no_checkout) {
 576                 if (get_oid(start_head.buf, &oid) < 0) {
 577                         res = error(_("invalid ref: '%s'"), start_head.buf);
 578                         goto finish;
 579                 }
 580                 if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
 581                                UPDATE_REFS_MSG_ON_ERR)) {
 582                         res = -1;
 583                         goto finish;
 584                 }
 585         }
 586
 587         if (pathspec_pos < argc - 1)
 588                 sq_quote_argv(&bisect_names, argv + pathspec_pos);
 589         write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
 590
 591         for (i = 0; i < states.nr; i++)
 592                 if (bisect_write(states.items[i].string,
 593                                  revs.items[i].string, terms, 1)) {
 594                         res = -1;
 595                         goto finish;
 596                 }
 597
 598         if (must_write_terms && write_terms(terms->term_bad,
 599                                             terms->term_good)) {
 600                 res = -1;
 601                 goto finish;
 602         }
 603
 604         res = bisect_append_log_quoted(argv);
 605         if (res)
 606                 res = -1;
 607
 608 finish:
 609         string_list_clear(&revs, 0);
 610         string_list_clear(&states, 0);
 611         strbuf_release(&start_head);
 612         strbuf_release(&bisect_names);
 613         return res;
 614 }
 615
 616 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 617 {
 618         enum {
 619                 NEXT_ALL = 1,
 620                 WRITE_TERMS,
 621                 BISECT_CLEAN_STATE,
 622                 CHECK_EXPECTED_REVS,
 623                 BISECT_RESET,
 624                 BISECT_WRITE,
 625                 CHECK_AND_SET_TERMS,
 626                 BISECT_NEXT_CHECK,
 627                 BISECT_TERMS,
 628                 BISECT_START
 629         } cmdmode = 0;
 630         int no_checkout = 0, res = 0, nolog = 0;
 631         struct option options[] = {
 632                 OPT_CMDMODE(0, "next-all", &cmdmode,
 633                          N_("perform 'git bisect next'"), NEXT_ALL),
 634                 OPT_CMDMODE(0, "write-terms", &cmdmode,
 635                          N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 636                 OPT_CMDMODE(0, "bisect-clean-state", &cmdmode,
 637                          N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
 638                 OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
 639                          N_("check for expected revs"), CHECK_EXPECTED_REVS),
 640                 OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 641                          N_("reset the bisection state"), BISECT_RESET),
 642                 OPT_CMDMODE(0, "bisect-write", &cmdmode,
 643                          N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
 644                 OPT_CMDMODE(0, "check-and-set-terms", &cmdmode,
 645                          N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
 646                 OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
 647                          N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
 648                 OPT_CMDMODE(0, "bisect-terms", &cmdmode,
 649                          N_("print out the bisect terms"), BISECT_TERMS),
 650                 OPT_CMDMODE(0, "bisect-start", &cmdmode,
 651                          N_("start the bisect session"), BISECT_START),
 652                 OPT_BOOL(0, "no-checkout", &no_checkout,
 653                          N_("update BISECT_HEAD instead of checking out the current commit")),
 654                 OPT_BOOL(0, "no-log", &nolog,
 655                          N_("no log for BISECT_WRITE")),
 656                 OPT_END()
 657         };
 658         struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
 659
 660         argc = parse_options(argc, argv, prefix, options,
 661                              git_bisect_helper_usage,
 662                              PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
 663
 664         if (!cmdmode)
 665                 usage_with_options(git_bisect_helper_usage, options);
 666
 667         switch (cmdmode) {
 668         case NEXT_ALL:
 669                 res = bisect_next_all(the_repository, prefix, no_checkout);
 670                 break;
 671         case WRITE_TERMS:
 672                 if (argc != 2)
 673                         return error(_("--write-terms requires two arguments"));
 674                 return write_terms(argv[0], argv[1]);
 675         case BISECT_CLEAN_STATE:
 676                 if (argc != 0)
 677                         return error(_("--bisect-clean-state requires no arguments"));
 678                 return bisect_clean_state();
 679         case CHECK_EXPECTED_REVS:
 680                 check_expected_revs(argv, argc);
 681                 return 0;
 682         case BISECT_RESET:
 683                 if (argc > 1)
 684                         return error(_("--bisect-reset requires either no argument or a commit"));
 685                 return !!bisect_reset(argc ? argv[0] : NULL);
 686         case BISECT_WRITE:
 687                 if (argc != 4 && argc != 5)
 688                         return error(_("--bisect-write requires either 4 or 5 arguments"));
 689                 set_terms(&terms, argv[3], argv[2]);
 690                 res = bisect_write(argv[0], argv[1], &terms, nolog);
 691                 break;
 692         case CHECK_AND_SET_TERMS:
 693                 if (argc != 3)
 694                         return error(_("--check-and-set-terms requires 3 arguments"));
 695                 set_terms(&terms, argv[2], argv[1]);
 696                 res = check_and_set_terms(&terms, argv[0]);
 697                 break;
 698         case BISECT_NEXT_CHECK:
 699                 if (argc != 2 && argc != 3)
 700                         return error(_("--bisect-next-check requires 2 or 3 arguments"));
 701                 set_terms(&terms, argv[1], argv[0]);
 702                 res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
 703                 break;
 704         case BISECT_TERMS:
 705                 if (argc > 1)
 706                         return error(_("--bisect-terms requires 0 or 1 argument"));
 707                 res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
 708                 break;
 709         case BISECT_START:
 710                 set_terms(&terms, "bad", "good");
 711                 res = bisect_start(&terms, no_checkout, argv, argc);
 712                 break;
 713         default:
 714                 return error("BUG: unknown subcommand '%d'", cmdmode);
 715         }
 716         free_terms(&terms);
 717
 718         /*
 719          * Handle early success
 720          * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
 721          */
 722         if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE)
 723                 res = BISECT_OK;
 724
 725         return abs(res);
 726 }