git.oblomov.eu Git - git/blob - 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 "strvec.h"
   8 #include "run-command.h"
   9 #include "prompt.h"
  10 #include "quote.h"
  11 #include "revision.h"
  12
  13 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
  14 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
  15 static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
  16 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
  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 static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
  21
  22 static const char * const git_bisect_helper_usage[] = {
  23         N_("git bisect--helper --next-all"),
  24         N_("git bisect--helper --write-terms <bad_term> <good_term>"),
  25         N_("git bisect--helper --bisect-clean-state"),
  26         N_("git bisect--helper --bisect-reset [<commit>]"),
  27         N_("git bisect--helper --bisect-write [--no-log] <state> <revision> <good_term> <bad_term>"),
  28         N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
  29         N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
  30         N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
  31         N_("git bisect--helper --bisect-start [--term-{new,bad}=<term> --term-{old,good}=<term>]"
  32                                             " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
  33         N_("git bisect--helper --bisect-next"),
  34         N_("git bisect--helper --bisect-auto-next"),
  35         N_("git bisect--helper --bisect-autostart"),
  36         NULL
  37 };
  38
  39 struct add_bisect_ref_data {
  40         struct rev_info *revs;
  41         unsigned int object_flags;
  42 };
  43
  44 struct bisect_terms {
  45         char *term_good;
  46         char *term_bad;
  47 };
  48
  49 static void free_terms(struct bisect_terms *terms)
  50 {
  51         FREE_AND_NULL(terms->term_good);
  52         FREE_AND_NULL(terms->term_bad);
  53 }
  54
  55 static void set_terms(struct bisect_terms *terms, const char *bad,
  56                       const char *good)
  57 {
  58         free((void *)terms->term_good);
  59         terms->term_good = xstrdup(good);
  60         free((void *)terms->term_bad);
  61         terms->term_bad = xstrdup(bad);
  62 }
  63
  64 static const char vocab_bad[] = "bad|new";
  65 static const char vocab_good[] = "good|old";
  66
  67 static int bisect_autostart(struct bisect_terms *terms);
  68
  69 /*
  70  * Check whether the string `term` belongs to the set of strings
  71  * included in the variable arguments.
  72  */
  73 LAST_ARG_MUST_BE_NULL
  74 static int one_of(const char *term, ...)
  75 {
  76         int res = 0;
  77         va_list matches;
  78         const char *match;
  79
  80         va_start(matches, term);
  81         while (!res && (match = va_arg(matches, const char *)))
  82                 res = !strcmp(term, match);
  83         va_end(matches);
  84
  85         return res;
  86 }
  87
  88 static int write_in_file(const char *path, const char *mode, const char *format, va_list args)
  89 {
  90         FILE *fp = NULL;
  91         int res = 0;
  92
  93         if (strcmp(mode, "w") && strcmp(mode, "a"))
  94                 BUG("write-in-file does not support '%s' mode", mode);
  95         fp = fopen(path, mode);
  96         if (!fp)
  97                 return error_errno(_("cannot open file '%s' in mode '%s'"), path, mode);
  98         res = vfprintf(fp, format, args);
  99
 100         if (res < 0) {
 101                 int saved_errno = errno;
 102                 fclose(fp);
 103                 errno = saved_errno;
 104                 return error_errno(_("could not write to file '%s'"), path);
 105         }
 106
 107         return fclose(fp);
 108 }
 109
 110 static int write_to_file(const char *path, const char *format, ...)
 111 {
 112         int res;
 113         va_list args;
 114
 115         va_start(args, format);
 116         res = write_in_file(path, "w", format, args);
 117         va_end(args);
 118
 119         return res;
 120 }
 121
 122 static int append_to_file(const char *path, const char *format, ...)
 123 {
 124         int res;
 125         va_list args;
 126
 127         va_start(args, format);
 128         res = write_in_file(path, "a", format, args);
 129         va_end(args);
 130
 131         return res;
 132 }
 133
 134 static int check_term_format(const char *term, const char *orig_term)
 135 {
 136         int res;
 137         char *new_term = xstrfmt("refs/bisect/%s", term);
 138
 139         res = check_refname_format(new_term, 0);
 140         free(new_term);
 141
 142         if (res)
 143                 return error(_("'%s' is not a valid term"), term);
 144
 145         if (one_of(term, "help", "start", "skip", "next", "reset",
 146                         "visualize", "view", "replay", "log", "run", "terms", NULL))
 147                 return error(_("can't use the builtin command '%s' as a term"), term);
 148
 149         /*
 150          * In theory, nothing prevents swapping completely good and bad,
 151          * but this situation could be confusing and hasn't been tested
 152          * enough. Forbid it for now.
 153          */
 154
 155         if ((strcmp(orig_term, "bad") && one_of(term, "bad", "new", NULL)) ||
 156                  (strcmp(orig_term, "good") && one_of(term, "good", "old", NULL)))
 157                 return error(_("can't change the meaning of the term '%s'"), term);
 158
 159         return 0;
 160 }
 161
 162 static int write_terms(const char *bad, const char *good)
 163 {
 164         int res;
 165
 166         if (!strcmp(bad, good))
 167                 return error(_("please use two different terms"));
 168
 169         if (check_term_format(bad, "bad") || check_term_format(good, "good"))
 170                 return -1;
 171
 172         res = write_to_file(git_path_bisect_terms(), "%s\n%s\n", bad, good);
 173
 174         return res;
 175 }
 176
 177 static int is_expected_rev(const char *expected_hex)
 178 {
 179         struct strbuf actual_hex = STRBUF_INIT;
 180         int res = 0;
 181         if (strbuf_read_file(&actual_hex, git_path_bisect_expected_rev(), 0) >= 40) {
 182                 strbuf_trim(&actual_hex);
 183                 res = !strcmp(actual_hex.buf, expected_hex);
 184         }
 185         strbuf_release(&actual_hex);
 186         return res;
 187 }
 188
 189 static void check_expected_revs(const char **revs, int rev_nr)
 190 {
 191         int i;
 192
 193         for (i = 0; i < rev_nr; i++) {
 194                 if (!is_expected_rev(revs[i])) {
 195                         unlink_or_warn(git_path_bisect_ancestors_ok());
 196                         unlink_or_warn(git_path_bisect_expected_rev());
 197                 }
 198         }
 199 }
 200
 201 static int bisect_reset(const char *commit)
 202 {
 203         struct strbuf branch = STRBUF_INIT;
 204
 205         if (!commit) {
 206                 if (strbuf_read_file(&branch, git_path_bisect_start(), 0) < 1) {
 207                         printf(_("We are not bisecting.\n"));
 208                         return 0;
 209                 }
 210                 strbuf_rtrim(&branch);
 211         } else {
 212                 struct object_id oid;
 213
 214                 if (get_oid_commit(commit, &oid))
 215                         return error(_("'%s' is not a valid commit"), commit);
 216                 strbuf_addstr(&branch, commit);
 217         }
 218
 219         if (!ref_exists("BISECT_HEAD")) {
 220                 struct strvec argv = STRVEC_INIT;
 221
 222                 strvec_pushl(&argv, "checkout", branch.buf, "--", NULL);
 223                 if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
 224                         error(_("could not check out original"
 225                                 " HEAD '%s'. Try 'git bisect"
 226                                 " reset <commit>'."), branch.buf);
 227                         strbuf_release(&branch);
 228                         strvec_clear(&argv);
 229                         return -1;
 230                 }
 231                 strvec_clear(&argv);
 232         }
 233
 234         strbuf_release(&branch);
 235         return bisect_clean_state();
 236 }
 237
 238 static void log_commit(FILE *fp, char *fmt, const char *state,
 239                        struct commit *commit)
 240 {
 241         struct pretty_print_context pp = {0};
 242         struct strbuf commit_msg = STRBUF_INIT;
 243         char *label = xstrfmt(fmt, state);
 244
 245         format_commit_message(commit, "%s", &commit_msg, &pp);
 246
 247         fprintf(fp, "# %s: [%s] %s\n", label, oid_to_hex(&commit->object.oid),
 248                 commit_msg.buf);
 249
 250         strbuf_release(&commit_msg);
 251         free(label);
 252 }
 253
 254 static int bisect_write(const char *state, const char *rev,
 255                         const struct bisect_terms *terms, int nolog)
 256 {
 257         struct strbuf tag = STRBUF_INIT;
 258         struct object_id oid;
 259         struct commit *commit;
 260         FILE *fp = NULL;
 261         int res = 0;
 262
 263         if (!strcmp(state, terms->term_bad)) {
 264                 strbuf_addf(&tag, "refs/bisect/%s", state);
 265         } else if (one_of(state, terms->term_good, "skip", NULL)) {
 266                 strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
 267         } else {
 268                 res = error(_("Bad bisect_write argument: %s"), state);
 269                 goto finish;
 270         }
 271
 272         if (get_oid(rev, &oid)) {
 273                 res = error(_("couldn't get the oid of the rev '%s'"), rev);
 274                 goto finish;
 275         }
 276
 277         if (update_ref(NULL, tag.buf, &oid, NULL, 0,
 278                        UPDATE_REFS_MSG_ON_ERR)) {
 279                 res = -1;
 280                 goto finish;
 281         }
 282
 283         fp = fopen(git_path_bisect_log(), "a");
 284         if (!fp) {
 285                 res = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
 286                 goto finish;
 287         }
 288
 289         commit = lookup_commit_reference(the_repository, &oid);
 290         log_commit(fp, "%s", state, commit);
 291
 292         if (!nolog)
 293                 fprintf(fp, "git bisect %s %s\n", state, rev);
 294
 295 finish:
 296         if (fp)
 297                 fclose(fp);
 298         strbuf_release(&tag);
 299         return res;
 300 }
 301
 302 static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
 303 {
 304         int has_term_file = !is_empty_or_missing_file(git_path_bisect_terms());
 305
 306         if (one_of(cmd, "skip", "start", "terms", NULL))
 307                 return 0;
 308
 309         if (has_term_file && strcmp(cmd, terms->term_bad) &&
 310             strcmp(cmd, terms->term_good))
 311                 return error(_("Invalid command: you're currently in a "
 312                                 "%s/%s bisect"), terms->term_bad,
 313                                 terms->term_good);
 314
 315         if (!has_term_file) {
 316                 if (one_of(cmd, "bad", "good", NULL)) {
 317                         set_terms(terms, "bad", "good");
 318                         return write_terms(terms->term_bad, terms->term_good);
 319                 }
 320                 if (one_of(cmd, "new", "old", NULL)) {
 321                         set_terms(terms, "new", "old");
 322                         return write_terms(terms->term_bad, terms->term_good);
 323                 }
 324         }
 325
 326         return 0;
 327 }
 328
 329 static int mark_good(const char *refname, const struct object_id *oid,
 330                      int flag, void *cb_data)
 331 {
 332         int *m_good = (int *)cb_data;
 333         *m_good = 0;
 334         return 1;
 335 }
 336
 337 static const char need_bad_and_good_revision_warning[] =
 338         N_("You need to give me at least one %s and %s revision.\n"
 339            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 340
 341 static const char need_bisect_start_warning[] =
 342         N_("You need to start by \"git bisect start\".\n"
 343            "You then need to give me at least one %s and %s revision.\n"
 344            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
 345
 346 static int decide_next(const struct bisect_terms *terms,
 347                        const char *current_term, int missing_good,
 348                        int missing_bad)
 349 {
 350         if (!missing_good && !missing_bad)
 351                 return 0;
 352         if (!current_term)
 353                 return -1;
 354
 355         if (missing_good && !missing_bad &&
 356             !strcmp(current_term, terms->term_good)) {
 357                 char *yesno;
 358                 /*
 359                  * have bad (or new) but not good (or old). We could bisect
 360                  * although this is less optimum.
 361                  */
 362                 warning(_("bisecting only with a %s commit"), terms->term_bad);
 363                 if (!isatty(0))
 364                         return 0;
 365                 /*
 366                  * TRANSLATORS: Make sure to include [Y] and [n] in your
 367                  * translation. The program will only accept English input
 368                  * at this point.
 369                  */
 370                 yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
 371                 if (starts_with(yesno, "N") || starts_with(yesno, "n"))
 372                         return -1;
 373                 return 0;
 374         }
 375
 376         if (!is_empty_or_missing_file(git_path_bisect_start()))
 377                 return error(_(need_bad_and_good_revision_warning),
 378                              vocab_bad, vocab_good, vocab_bad, vocab_good);
 379         else
 380                 return error(_(need_bisect_start_warning),
 381                              vocab_good, vocab_bad, vocab_good, vocab_bad);
 382 }
 383
 384 static int bisect_next_check(const struct bisect_terms *terms,
 385                              const char *current_term)
 386 {
 387         int missing_good = 1, missing_bad = 1;
 388         char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
 389         char *good_glob = xstrfmt("%s-*", terms->term_good);
 390
 391         if (ref_exists(bad_ref))
 392                 missing_bad = 0;
 393
 394         for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
 395                              (void *) &missing_good);
 396
 397         free(good_glob);
 398         free(bad_ref);
 399
 400         return decide_next(terms, current_term, missing_good, missing_bad);
 401 }
 402
 403 static int get_terms(struct bisect_terms *terms)
 404 {
 405         struct strbuf str = STRBUF_INIT;
 406         FILE *fp = NULL;
 407         int res = 0;
 408
 409         fp = fopen(git_path_bisect_terms(), "r");
 410         if (!fp) {
 411                 res = -1;
 412                 goto finish;
 413         }
 414
 415         free_terms(terms);
 416         strbuf_getline_lf(&str, fp);
 417         terms->term_bad = strbuf_detach(&str, NULL);
 418         strbuf_getline_lf(&str, fp);
 419         terms->term_good = strbuf_detach(&str, NULL);
 420
 421 finish:
 422         if (fp)
 423                 fclose(fp);
 424         strbuf_release(&str);
 425         return res;
 426 }
 427
 428 static int bisect_terms(struct bisect_terms *terms, const char *option)
 429 {
 430         if (get_terms(terms))
 431                 return error(_("no terms defined"));
 432
 433         if (option == NULL) {
 434                 printf(_("Your current terms are %s for the old state\n"
 435                          "and %s for the new state.\n"),
 436                        terms->term_good, terms->term_bad);
 437                 return 0;
 438         }
 439         if (one_of(option, "--term-good", "--term-old", NULL))
 440                 printf("%s\n", terms->term_good);
 441         else if (one_of(option, "--term-bad", "--term-new", NULL))
 442                 printf("%s\n", terms->term_bad);
 443         else
 444                 return error(_("invalid argument %s for 'git bisect terms'.\n"
 445                                "Supported options are: "
 446                                "--term-good|--term-old and "
 447                                "--term-bad|--term-new."), option);
 448
 449         return 0;
 450 }
 451
 452 static int bisect_append_log_quoted(const char **argv)
 453 {
 454         int res = 0;
 455         FILE *fp = fopen(git_path_bisect_log(), "a");
 456         struct strbuf orig_args = STRBUF_INIT;
 457
 458         if (!fp)
 459                 return -1;
 460
 461         if (fprintf(fp, "git bisect start") < 1) {
 462                 res = -1;
 463                 goto finish;
 464         }
 465
 466         sq_quote_argv(&orig_args, argv);
 467         if (fprintf(fp, "%s\n", orig_args.buf) < 1)
 468                 res = -1;
 469
 470 finish:
 471         fclose(fp);
 472         strbuf_release(&orig_args);
 473         return res;
 474 }
 475
 476 static int add_bisect_ref(const char *refname, const struct object_id *oid,
 477                           int flags, void *cb)
 478 {
 479         struct add_bisect_ref_data *data = cb;
 480
 481         add_pending_oid(data->revs, refname, oid, data->object_flags);
 482
 483         return 0;
 484 }
 485
 486 static int prepare_revs(struct bisect_terms *terms, struct rev_info *revs)
 487 {
 488         int res = 0;
 489         struct add_bisect_ref_data cb = { revs };
 490         char *good = xstrfmt("%s-*", terms->term_good);
 491
 492         /*
 493          * We cannot use terms->term_bad directly in
 494          * for_each_glob_ref_in() and we have to append a '*' to it,
 495          * otherwise for_each_glob_ref_in() will append '/' and '*'.
 496          */
 497         char *bad = xstrfmt("%s*", terms->term_bad);
 498
 499         /*
 500          * It is important to reset the flags used by revision walks
 501          * as the previous call to bisect_next_all() in turn
 502          * sets up a revision walk.
 503          */
 504         reset_revision_walk();
 505         init_revisions(revs, NULL);
 506         setup_revisions(0, NULL, revs, NULL);
 507         for_each_glob_ref_in(add_bisect_ref, bad, "refs/bisect/", &cb);
 508         cb.object_flags = UNINTERESTING;
 509         for_each_glob_ref_in(add_bisect_ref, good, "refs/bisect/", &cb);
 510         if (prepare_revision_walk(revs))
 511                 res = error(_("revision walk setup failed\n"));
 512
 513         free(good);
 514         free(bad);
 515         return res;
 516 }
 517
 518 static int bisect_skipped_commits(struct bisect_terms *terms)
 519 {
 520         int res;
 521         FILE *fp = NULL;
 522         struct rev_info revs;
 523         struct commit *commit;
 524         struct pretty_print_context pp = {0};
 525         struct strbuf commit_name = STRBUF_INIT;
 526
 527         res = prepare_revs(terms, &revs);
 528         if (res)
 529                 return res;
 530
 531         fp = fopen(git_path_bisect_log(), "a");
 532         if (!fp)
 533                 return error_errno(_("could not open '%s' for appending"),
 534                                   git_path_bisect_log());
 535
 536         if (fprintf(fp, "# only skipped commits left to test\n") < 0)
 537                 return error_errno(_("failed to write to '%s'"), git_path_bisect_log());
 538
 539         while ((commit = get_revision(&revs)) != NULL) {
 540                 strbuf_reset(&commit_name);
 541                 format_commit_message(commit, "%s",
 542                                       &commit_name, &pp);
 543                 fprintf(fp, "# possible first %s commit: [%s] %s\n",
 544                         terms->term_bad, oid_to_hex(&commit->object.oid),
 545                         commit_name.buf);
 546         }
 547
 548         /*
 549          * Reset the flags used by revision walks in case
 550          * there is another revision walk after this one.
 551          */
 552         reset_revision_walk();
 553
 554         strbuf_release(&commit_name);
 555         fclose(fp);
 556         return 0;
 557 }
 558
 559 static int bisect_successful(struct bisect_terms *terms)
 560 {
 561         struct object_id oid;
 562         struct commit *commit;
 563         struct pretty_print_context pp = {0};
 564         struct strbuf commit_name = STRBUF_INIT;
 565         char *bad_ref = xstrfmt("refs/bisect/%s",terms->term_bad);
 566         int res;
 567
 568         read_ref(bad_ref, &oid);
 569         commit = lookup_commit_reference_by_name(bad_ref);
 570         format_commit_message(commit, "%s", &commit_name, &pp);
 571
 572         res = append_to_file(git_path_bisect_log(), "# first %s commit: [%s] %s\n",
 573                             terms->term_bad, oid_to_hex(&commit->object.oid),
 574                             commit_name.buf);
 575
 576         strbuf_release(&commit_name);
 577         free(bad_ref);
 578         return res;
 579 }
 580
 581 static enum bisect_error bisect_next(struct bisect_terms *terms, const char *prefix)
 582 {
 583         enum bisect_error res;
 584
 585         if (bisect_autostart(terms))
 586                 return BISECT_FAILED;
 587
 588         if (bisect_next_check(terms, terms->term_good))
 589                 return BISECT_FAILED;
 590
 591         /* Perform all bisection computation */
 592         res = bisect_next_all(the_repository, prefix);
 593
 594         if (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND) {
 595                 res = bisect_successful(terms);
 596                 return res ? res : BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
 597         } else if (res == BISECT_ONLY_SKIPPED_LEFT) {
 598                 res = bisect_skipped_commits(terms);
 599                 return res ? res : BISECT_ONLY_SKIPPED_LEFT;
 600         }
 601         return res;
 602 }
 603
 604 static enum bisect_error bisect_auto_next(struct bisect_terms *terms, const char *prefix)
 605 {
 606         if (bisect_next_check(terms, NULL))
 607                 return BISECT_OK;
 608
 609         return bisect_next(terms, prefix);
 610 }
 611
 612 static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
 613 {
 614         int no_checkout = 0;
 615         int first_parent_only = 0;
 616         int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
 617         int flags, pathspec_pos, res = 0;
 618         struct string_list revs = STRING_LIST_INIT_DUP;
 619         struct string_list states = STRING_LIST_INIT_DUP;
 620         struct strbuf start_head = STRBUF_INIT;
 621         struct strbuf bisect_names = STRBUF_INIT;
 622         struct object_id head_oid;
 623         struct object_id oid;
 624         const char *head;
 625
 626         if (is_bare_repository())
 627                 no_checkout = 1;
 628
 629         /*
 630          * Check for one bad and then some good revisions
 631          */
 632         for (i = 0; i < argc; i++) {
 633                 if (!strcmp(argv[i], "--")) {
 634                         has_double_dash = 1;
 635                         break;
 636                 }
 637         }
 638
 639         for (i = 0; i < argc; i++) {
 640                 const char *arg = argv[i];
 641                 if (!strcmp(argv[i], "--")) {
 642                         break;
 643                 } else if (!strcmp(arg, "--no-checkout")) {
 644                         no_checkout = 1;
 645                 } else if (!strcmp(arg, "--first-parent")) {
 646                         first_parent_only = 1;
 647                 } else if (!strcmp(arg, "--term-good") ||
 648                          !strcmp(arg, "--term-old")) {
 649                         i++;
 650                         if (argc <= i)
 651                                 return error(_("'' is not a valid term"));
 652                         must_write_terms = 1;
 653                         free((void *) terms->term_good);
 654                         terms->term_good = xstrdup(argv[i]);
 655                 } else if (skip_prefix(arg, "--term-good=", &arg) ||
 656                            skip_prefix(arg, "--term-old=", &arg)) {
 657                         must_write_terms = 1;
 658                         free((void *) terms->term_good);
 659                         terms->term_good = xstrdup(arg);
 660                 } else if (!strcmp(arg, "--term-bad") ||
 661                          !strcmp(arg, "--term-new")) {
 662                         i++;
 663                         if (argc <= i)
 664                                 return error(_("'' is not a valid term"));
 665                         must_write_terms = 1;
 666                         free((void *) terms->term_bad);
 667                         terms->term_bad = xstrdup(argv[i]);
 668                 } else if (skip_prefix(arg, "--term-bad=", &arg) ||
 669                            skip_prefix(arg, "--term-new=", &arg)) {
 670                         must_write_terms = 1;
 671                         free((void *) terms->term_bad);
 672                         terms->term_bad = xstrdup(arg);
 673                 } else if (starts_with(arg, "--")) {
 674                         return error(_("unrecognized option: '%s'"), arg);
 675                 } else if (!get_oidf(&oid, "%s^{commit}", arg)) {
 676                         string_list_append(&revs, oid_to_hex(&oid));
 677                 } else if (has_double_dash) {
 678                         die(_("'%s' does not appear to be a valid "
 679                               "revision"), arg);
 680                 } else {
 681                         break;
 682                 }
 683         }
 684         pathspec_pos = i;
 685
 686         /*
 687          * The user ran "git bisect start <sha1> <sha1>", hence did not
 688          * explicitly specify the terms, but we are already starting to
 689          * set references named with the default terms, and won't be able
 690          * to change afterwards.
 691          */
 692         if (revs.nr)
 693                 must_write_terms = 1;
 694         for (i = 0; i < revs.nr; i++) {
 695                 if (bad_seen) {
 696                         string_list_append(&states, terms->term_good);
 697                 } else {
 698                         bad_seen = 1;
 699                         string_list_append(&states, terms->term_bad);
 700                 }
 701         }
 702
 703         /*
 704          * Verify HEAD
 705          */
 706         head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
 707         if (!head)
 708                 if (get_oid("HEAD", &head_oid))
 709                         return error(_("bad HEAD - I need a HEAD"));
 710
 711         /*
 712          * Check if we are bisecting
 713          */
 714         if (!is_empty_or_missing_file(git_path_bisect_start())) {
 715                 /* Reset to the rev from where we started */
 716                 strbuf_read_file(&start_head, git_path_bisect_start(), 0);
 717                 strbuf_trim(&start_head);
 718                 if (!no_checkout) {
 719                         struct strvec argv = STRVEC_INIT;
 720
 721                         strvec_pushl(&argv, "checkout", start_head.buf,
 722                                      "--", NULL);
 723                         if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
 724                                 res = error(_("checking out '%s' failed."
 725                                                  " Try 'git bisect start "
 726                                                  "<valid-branch>'."),
 727                                                start_head.buf);
 728                                 goto finish;
 729                         }
 730                 }
 731         } else {
 732                 /* Get the rev from where we start. */
 733                 if (!get_oid(head, &head_oid) &&
 734                     !starts_with(head, "refs/heads/")) {
 735                         strbuf_reset(&start_head);
 736                         strbuf_addstr(&start_head, oid_to_hex(&head_oid));
 737                 } else if (!get_oid(head, &head_oid) &&
 738                            skip_prefix(head, "refs/heads/", &head)) {
 739                         /*
 740                          * This error message should only be triggered by
 741                          * cogito usage, and cogito users should understand
 742                          * it relates to cg-seek.
 743                          */
 744                         if (!is_empty_or_missing_file(git_path_head_name()))
 745                                 return error(_("won't bisect on cg-seek'ed tree"));
 746                         strbuf_addstr(&start_head, head);
 747                 } else {
 748                         return error(_("bad HEAD - strange symbolic ref"));
 749                 }
 750         }
 751
 752         /*
 753          * Get rid of any old bisect state.
 754          */
 755         if (bisect_clean_state())
 756                 return -1;
 757
 758         /*
 759          * In case of mistaken revs or checkout error, or signals received,
 760          * "bisect_auto_next" below may exit or misbehave.
 761          * We have to trap this to be able to clean up using
 762          * "bisect_clean_state".
 763          */
 764
 765         /*
 766          * Write new start state
 767          */
 768         write_file(git_path_bisect_start(), "%s\n", start_head.buf);
 769
 770         if (first_parent_only)
 771                 write_file(git_path_bisect_first_parent(), "\n");
 772
 773         if (no_checkout) {
 774                 if (get_oid(start_head.buf, &oid) < 0) {
 775                         res = error(_("invalid ref: '%s'"), start_head.buf);
 776                         goto finish;
 777                 }
 778                 if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
 779                                UPDATE_REFS_MSG_ON_ERR)) {
 780                         res = -1;
 781                         goto finish;
 782                 }
 783         }
 784
 785         if (pathspec_pos < argc - 1)
 786                 sq_quote_argv(&bisect_names, argv + pathspec_pos);
 787         write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
 788
 789         for (i = 0; i < states.nr; i++)
 790                 if (bisect_write(states.items[i].string,
 791                                  revs.items[i].string, terms, 1)) {
 792                         res = -1;
 793                         goto finish;
 794                 }
 795
 796         if (must_write_terms && write_terms(terms->term_bad,
 797                                             terms->term_good)) {
 798                 res = -1;
 799                 goto finish;
 800         }
 801
 802         res = bisect_append_log_quoted(argv);
 803         if (res)
 804                 res = -1;
 805
 806 finish:
 807         string_list_clear(&revs, 0);
 808         string_list_clear(&states, 0);
 809         strbuf_release(&start_head);
 810         strbuf_release(&bisect_names);
 811         return res;
 812 }
 813
 814 static inline int file_is_not_empty(const char *path)
 815 {
 816         return !is_empty_or_missing_file(path);
 817 }
 818
 819 static int bisect_autostart(struct bisect_terms *terms)
 820 {
 821         int res;
 822         const char *yesno;
 823
 824         if (file_is_not_empty(git_path_bisect_start()))
 825                 return 0;
 826
 827         fprintf_ln(stderr, _("You need to start by \"git bisect "
 828                           "start\"\n"));
 829
 830         if (!isatty(STDIN_FILENO))
 831                 return -1;
 832
 833         /*
 834          * TRANSLATORS: Make sure to include [Y] and [n] in your
 835          * translation. The program will only accept English input
 836          * at this point.
 837          */
 838         yesno = git_prompt(_("Do you want me to do it for you "
 839                              "[Y/n]? "), PROMPT_ECHO);
 840         res = tolower(*yesno) == 'n' ?
 841                 -1 : bisect_start(terms, empty_strvec, 0);
 842
 843         return res;
 844 }
 845
 846 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 847 {
 848         enum {
 849                 NEXT_ALL = 1,
 850                 WRITE_TERMS,
 851                 BISECT_CLEAN_STATE,
 852                 CHECK_EXPECTED_REVS,
 853                 BISECT_RESET,
 854                 BISECT_WRITE,
 855                 CHECK_AND_SET_TERMS,
 856                 BISECT_NEXT_CHECK,
 857                 BISECT_TERMS,
 858                 BISECT_START,
 859                 BISECT_AUTOSTART,
 860                 BISECT_NEXT,
 861                 BISECT_AUTO_NEXT
 862         } cmdmode = 0;
 863         int res = 0, nolog = 0;
 864         struct option options[] = {
 865                 OPT_CMDMODE(0, "next-all", &cmdmode,
 866                          N_("perform 'git bisect next'"), NEXT_ALL),
 867                 OPT_CMDMODE(0, "write-terms", &cmdmode,
 868                          N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
 869                 OPT_CMDMODE(0, "bisect-clean-state", &cmdmode,
 870                          N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
 871                 OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
 872                          N_("check for expected revs"), CHECK_EXPECTED_REVS),
 873                 OPT_CMDMODE(0, "bisect-reset", &cmdmode,
 874                          N_("reset the bisection state"), BISECT_RESET),
 875                 OPT_CMDMODE(0, "bisect-write", &cmdmode,
 876                          N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
 877                 OPT_CMDMODE(0, "check-and-set-terms", &cmdmode,
 878                          N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
 879                 OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
 880                          N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
 881                 OPT_CMDMODE(0, "bisect-terms", &cmdmode,
 882                          N_("print out the bisect terms"), BISECT_TERMS),
 883                 OPT_CMDMODE(0, "bisect-start", &cmdmode,
 884                          N_("start the bisect session"), BISECT_START),
 885                 OPT_CMDMODE(0, "bisect-next", &cmdmode,
 886                          N_("find the next bisection commit"), BISECT_NEXT),
 887                 OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
 888                          N_("verify the next bisection state then checkout the next bisection commit"), BISECT_AUTO_NEXT),
 889                 OPT_CMDMODE(0, "bisect-autostart", &cmdmode,
 890                          N_("start the bisection if it has not yet been started"), BISECT_AUTOSTART),
 891                 OPT_BOOL(0, "no-log", &nolog,
 892                          N_("no log for BISECT_WRITE")),
 893                 OPT_END()
 894         };
 895         struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
 896
 897         argc = parse_options(argc, argv, prefix, options,
 898                              git_bisect_helper_usage,
 899                              PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
 900
 901         if (!cmdmode)
 902                 usage_with_options(git_bisect_helper_usage, options);
 903
 904         switch (cmdmode) {
 905         case NEXT_ALL:
 906                 res = bisect_next_all(the_repository, prefix);
 907                 break;
 908         case WRITE_TERMS:
 909                 if (argc != 2)
 910                         return error(_("--write-terms requires two arguments"));
 911                 return write_terms(argv[0], argv[1]);
 912         case BISECT_CLEAN_STATE:
 913                 if (argc != 0)
 914                         return error(_("--bisect-clean-state requires no arguments"));
 915                 return bisect_clean_state();
 916         case CHECK_EXPECTED_REVS:
 917                 check_expected_revs(argv, argc);
 918                 return 0;
 919         case BISECT_RESET:
 920                 if (argc > 1)
 921                         return error(_("--bisect-reset requires either no argument or a commit"));
 922                 return !!bisect_reset(argc ? argv[0] : NULL);
 923         case BISECT_WRITE:
 924                 if (argc != 4 && argc != 5)
 925                         return error(_("--bisect-write requires either 4 or 5 arguments"));
 926                 set_terms(&terms, argv[3], argv[2]);
 927                 res = bisect_write(argv[0], argv[1], &terms, nolog);
 928                 break;
 929         case CHECK_AND_SET_TERMS:
 930                 if (argc != 3)
 931                         return error(_("--check-and-set-terms requires 3 arguments"));
 932                 set_terms(&terms, argv[2], argv[1]);
 933                 res = check_and_set_terms(&terms, argv[0]);
 934                 break;
 935         case BISECT_NEXT_CHECK:
 936                 if (argc != 2 && argc != 3)
 937                         return error(_("--bisect-next-check requires 2 or 3 arguments"));
 938                 set_terms(&terms, argv[1], argv[0]);
 939                 res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
 940                 break;
 941         case BISECT_TERMS:
 942                 if (argc > 1)
 943                         return error(_("--bisect-terms requires 0 or 1 argument"));
 944                 res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
 945                 break;
 946         case BISECT_START:
 947                 set_terms(&terms, "bad", "good");
 948                 res = bisect_start(&terms, argv, argc);
 949                 break;
 950         case BISECT_NEXT:
 951                 if (argc)
 952                         return error(_("--bisect-next requires 0 arguments"));
 953                 get_terms(&terms);
 954                 res = bisect_next(&terms, prefix);
 955                 break;
 956         case BISECT_AUTO_NEXT:
 957                 if (argc)
 958                         return error(_("--bisect-auto-next requires 0 arguments"));
 959                 get_terms(&terms);
 960                 res = bisect_auto_next(&terms, prefix);
 961                 break;
 962         case BISECT_AUTOSTART:
 963                 if (argc)
 964                         return error(_("--bisect-autostart does not accept arguments"));
 965                 set_terms(&terms, "bad", "good");
 966                 res = bisect_autostart(&terms);
 967                 break;
 968         default:
 969                 BUG("unknown subcommand %d", cmdmode);
 970         }
 971         free_terms(&terms);
 972
 973         /*
 974          * Handle early success
 975          * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
 976          */
 977         if ((res == BISECT_INTERNAL_SUCCESS_MERGE_BASE) || (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND))
 978                 res = BISECT_OK;
 979
 980         return -res;
 981 }