about summary refs log tree commit diff
path: root/third_party/git/builtin/bisect--helper.c
blob: 7512b880f0d67fbe5dba8de93271324b8338d7d9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
#include "builtin.h"
#include "cache.h"
#include "parse-options.h"
#include "bisect.h"
#include "refs.h"
#include "dir.h"
#include "strvec.h"
#include "run-command.h"
#include "prompt.h"
#include "quote.h"
#include "revision.h"

static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
static GIT_PATH_FUNC(git_path_head_name, "head-name")
static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")

static const char * const git_bisect_helper_usage[] = {
	N_("git bisect--helper --next-all"),
	N_("git bisect--helper --write-terms <bad_term> <good_term>"),
	N_("git bisect--helper --bisect-clean-state"),
	N_("git bisect--helper --bisect-reset [<commit>]"),
	N_("git bisect--helper --bisect-write [--no-log] <state> <revision> <good_term> <bad_term>"),
	N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
	N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
	N_("git bisect--helper --bisect-start [--term-{new,bad}=<term> --term-{old,good}=<term>]"
					    " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
	N_("git bisect--helper --bisect-next"),
	N_("git bisect--helper --bisect-auto-next"),
	N_("git bisect--helper --bisect-autostart"),
	NULL
};

struct add_bisect_ref_data {
	struct rev_info *revs;
	unsigned int object_flags;
};

struct bisect_terms {
	char *term_good;
	char *term_bad;
};

static void free_terms(struct bisect_terms *terms)
{
	FREE_AND_NULL(terms->term_good);
	FREE_AND_NULL(terms->term_bad);
}

static void set_terms(struct bisect_terms *terms, const char *bad,
		      const char *good)
{
	free((void *)terms->term_good);
	terms->term_good = xstrdup(good);
	free((void *)terms->term_bad);
	terms->term_bad = xstrdup(bad);
}

static const char vocab_bad[] = "bad|new";
static const char vocab_good[] = "good|old";

static int bisect_autostart(struct bisect_terms *terms);

/*
 * Check whether the string `term` belongs to the set of strings
 * included in the variable arguments.
 */
LAST_ARG_MUST_BE_NULL
static int one_of(const char *term, ...)
{
	int res = 0;
	va_list matches;
	const char *match;

	va_start(matches, term);
	while (!res && (match = va_arg(matches, const char *)))
		res = !strcmp(term, match);
	va_end(matches);

	return res;
}

static int write_in_file(const char *path, const char *mode, const char *format, va_list args)
{
	FILE *fp = NULL;
	int res = 0;

	if (strcmp(mode, "w") && strcmp(mode, "a"))
		BUG("write-in-file does not support '%s' mode", mode);
	fp = fopen(path, mode);
	if (!fp)
		return error_errno(_("cannot open file '%s' in mode '%s'"), path, mode);
	res = vfprintf(fp, format, args);

	if (res < 0) {
		int saved_errno = errno;
		fclose(fp);
		errno = saved_errno;
		return error_errno(_("could not write to file '%s'"), path);
	}

	return fclose(fp);
}

static int write_to_file(const char *path, const char *format, ...)
{
	int res;
	va_list args;

	va_start(args, format);
	res = write_in_file(path, "w", format, args);
	va_end(args);

	return res;
}

static int append_to_file(const char *path, const char *format, ...)
{
	int res;
	va_list args;

	va_start(args, format);
	res = write_in_file(path, "a", format, args);
	va_end(args);

	return res;
}

static int check_term_format(const char *term, const char *orig_term)
{
	int res;
	char *new_term = xstrfmt("refs/bisect/%s", term);

	res = check_refname_format(new_term, 0);
	free(new_term);

	if (res)
		return error(_("'%s' is not a valid term"), term);

	if (one_of(term, "help", "start", "skip", "next", "reset",
			"visualize", "view", "replay", "log", "run", "terms", NULL))
		return error(_("can't use the builtin command '%s' as a term"), term);

	/*
	 * In theory, nothing prevents swapping completely good and bad,
	 * but this situation could be confusing and hasn't been tested
	 * enough. Forbid it for now.
	 */

	if ((strcmp(orig_term, "bad") && one_of(term, "bad", "new", NULL)) ||
		 (strcmp(orig_term, "good") && one_of(term, "good", "old", NULL)))
		return error(_("can't change the meaning of the term '%s'"), term);

	return 0;
}

static int write_terms(const char *bad, const char *good)
{
	int res;

	if (!strcmp(bad, good))
		return error(_("please use two different terms"));

	if (check_term_format(bad, "bad") || check_term_format(good, "good"))
		return -1;

	res = write_to_file(git_path_bisect_terms(), "%s\n%s\n", bad, good);

	return res;
}

static int is_expected_rev(const char *expected_hex)
{
	struct strbuf actual_hex = STRBUF_INIT;
	int res = 0;
	if (strbuf_read_file(&actual_hex, git_path_bisect_expected_rev(), 0) >= 40) {
		strbuf_trim(&actual_hex);
		res = !strcmp(actual_hex.buf, expected_hex);
	}
	strbuf_release(&actual_hex);
	return res;
}

static void check_expected_revs(const char **revs, int rev_nr)
{
	int i;

	for (i = 0; i < rev_nr; i++) {
		if (!is_expected_rev(revs[i])) {
			unlink_or_warn(git_path_bisect_ancestors_ok());
			unlink_or_warn(git_path_bisect_expected_rev());
		}
	}
}

static int bisect_reset(const char *commit)
{
	struct strbuf branch = STRBUF_INIT;

	if (!commit) {
		if (strbuf_read_file(&branch, git_path_bisect_start(), 0) < 1) {
			printf(_("We are not bisecting.\n"));
			return 0;
		}
		strbuf_rtrim(&branch);
	} else {
		struct object_id oid;

		if (get_oid_commit(commit, &oid))
			return error(_("'%s' is not a valid commit"), commit);
		strbuf_addstr(&branch, commit);
	}

	if (!ref_exists("BISECT_HEAD")) {
		struct strvec argv = STRVEC_INIT;

		strvec_pushl(&argv, "checkout", branch.buf, "--", NULL);
		if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
			error(_("could not check out original"
				" HEAD '%s'. Try 'git bisect"
				" reset <commit>'."), branch.buf);
			strbuf_release(&branch);
			strvec_clear(&argv);
			return -1;
		}
		strvec_clear(&argv);
	}

	strbuf_release(&branch);
	return bisect_clean_state();
}

static void log_commit(FILE *fp, char *fmt, const char *state,
		       struct commit *commit)
{
	struct pretty_print_context pp = {0};
	struct strbuf commit_msg = STRBUF_INIT;
	char *label = xstrfmt(fmt, state);

	format_commit_message(commit, "%s", &commit_msg, &pp);

	fprintf(fp, "# %s: [%s] %s\n", label, oid_to_hex(&commit->object.oid),
		commit_msg.buf);

	strbuf_release(&commit_msg);
	free(label);
}

static int bisect_write(const char *state, const char *rev,
			const struct bisect_terms *terms, int nolog)
{
	struct strbuf tag = STRBUF_INIT;
	struct object_id oid;
	struct commit *commit;
	FILE *fp = NULL;
	int res = 0;

	if (!strcmp(state, terms->term_bad)) {
		strbuf_addf(&tag, "refs/bisect/%s", state);
	} else if (one_of(state, terms->term_good, "skip", NULL)) {
		strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
	} else {
		res = error(_("Bad bisect_write argument: %s"), state);
		goto finish;
	}

	if (get_oid(rev, &oid)) {
		res = error(_("couldn't get the oid of the rev '%s'"), rev);
		goto finish;
	}

	if (update_ref(NULL, tag.buf, &oid, NULL, 0,
		       UPDATE_REFS_MSG_ON_ERR)) {
		res = -1;
		goto finish;
	}

	fp = fopen(git_path_bisect_log(), "a");
	if (!fp) {
		res = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
		goto finish;
	}

	commit = lookup_commit_reference(the_repository, &oid);
	log_commit(fp, "%s", state, commit);

	if (!nolog)
		fprintf(fp, "git bisect %s %s\n", state, rev);

finish:
	if (fp)
		fclose(fp);
	strbuf_release(&tag);
	return res;
}

static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
{
	int has_term_file = !is_empty_or_missing_file(git_path_bisect_terms());

	if (one_of(cmd, "skip", "start", "terms", NULL))
		return 0;

	if (has_term_file && strcmp(cmd, terms->term_bad) &&
	    strcmp(cmd, terms->term_good))
		return error(_("Invalid command: you're currently in a "
				"%s/%s bisect"), terms->term_bad,
				terms->term_good);

	if (!has_term_file) {
		if (one_of(cmd, "bad", "good", NULL)) {
			set_terms(terms, "bad", "good");
			return write_terms(terms->term_bad, terms->term_good);
		}
		if (one_of(cmd, "new", "old", NULL)) {
			set_terms(terms, "new", "old");
			return write_terms(terms->term_bad, terms->term_good);
		}
	}

	return 0;
}

static int mark_good(const char *refname, const struct object_id *oid,
		     int flag, void *cb_data)
{
	int *m_good = (int *)cb_data;
	*m_good = 0;
	return 1;
}

static const char need_bad_and_good_revision_warning[] =
	N_("You need to give me at least one %s and %s revision.\n"
	   "You can use \"git bisect %s\" and \"git bisect %s\" for that.");

static const char need_bisect_start_warning[] =
	N_("You need to start by \"git bisect start\".\n"
	   "You then need to give me at least one %s and %s revision.\n"
	   "You can use \"git bisect %s\" and \"git bisect %s\" for that.");

static int decide_next(const struct bisect_terms *terms,
		       const char *current_term, int missing_good,
		       int missing_bad)
{
	if (!missing_good && !missing_bad)
		return 0;
	if (!current_term)
		return -1;

	if (missing_good && !missing_bad &&
	    !strcmp(current_term, terms->term_good)) {
		char *yesno;
		/*
		 * have bad (or new) but not good (or old). We could bisect
		 * although this is less optimum.
		 */
		warning(_("bisecting only with a %s commit"), terms->term_bad);
		if (!isatty(0))
			return 0;
		/*
		 * TRANSLATORS: Make sure to include [Y] and [n] in your
		 * translation. The program will only accept English input
		 * at this point.
		 */
		yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
		if (starts_with(yesno, "N") || starts_with(yesno, "n"))
			return -1;
		return 0;
	}

	if (!is_empty_or_missing_file(git_path_bisect_start()))
		return error(_(need_bad_and_good_revision_warning),
			     vocab_bad, vocab_good, vocab_bad, vocab_good);
	else
		return error(_(need_bisect_start_warning),
			     vocab_good, vocab_bad, vocab_good, vocab_bad);
}

static int bisect_next_check(const struct bisect_terms *terms,
			     const char *current_term)
{
	int missing_good = 1, missing_bad = 1;
	char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
	char *good_glob = xstrfmt("%s-*", terms->term_good);

	if (ref_exists(bad_ref))
		missing_bad = 0;

	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
			     (void *) &missing_good);

	free(good_glob);
	free(bad_ref);

	return decide_next(terms, current_term, missing_good, missing_bad);
}

static int get_terms(struct bisect_terms *terms)
{
	struct strbuf str = STRBUF_INIT;
	FILE *fp = NULL;
	int res = 0;

	fp = fopen(git_path_bisect_terms(), "r");
	if (!fp) {
		res = -1;
		goto finish;
	}

	free_terms(terms);
	strbuf_getline_lf(&str, fp);
	terms->term_bad = strbuf_detach(&str, NULL);
	strbuf_getline_lf(&str, fp);
	terms->term_good = strbuf_detach(&str, NULL);

finish:
	if (fp)
		fclose(fp);
	strbuf_release(&str);
	return res;
}

static int bisect_terms(struct bisect_terms *terms, const char *option)
{
	if (get_terms(terms))
		return error(_("no terms defined"));

	if (option == NULL) {
		printf(_("Your current terms are %s for the old state\n"
			 "and %s for the new state.\n"),
		       terms->term_good, terms->term_bad);
		return 0;
	}
	if (one_of(option, "--term-good", "--term-old", NULL))
		printf("%s\n", terms->term_good);
	else if (one_of(option, "--term-bad", "--term-new", NULL))
		printf("%s\n", terms->term_bad);
	else
		return error(_("invalid argument %s for 'git bisect terms'.\n"
			       "Supported options are: "
			       "--term-good|--term-old and "
			       "--term-bad|--term-new."), option);

	return 0;
}

static int bisect_append_log_quoted(const char **argv)
{
	int res = 0;
	FILE *fp = fopen(git_path_bisect_log(), "a");
	struct strbuf orig_args = STRBUF_INIT;

	if (!fp)
		return -1;

	if (fprintf(fp, "git bisect start") < 1) {
		res = -1;
		goto finish;
	}

	sq_quote_argv(&orig_args, argv);
	if (fprintf(fp, "%s\n", orig_args.buf) < 1)
		res = -1;

finish:
	fclose(fp);
	strbuf_release(&orig_args);
	return res;
}

static int add_bisect_ref(const char *refname, const struct object_id *oid,
			  int flags, void *cb)
{
	struct add_bisect_ref_data *data = cb;

	add_pending_oid(data->revs, refname, oid, data->object_flags);

	return 0;
}

static int prepare_revs(struct bisect_terms *terms, struct rev_info *revs)
{
	int res = 0;
	struct add_bisect_ref_data cb = { revs };
	char *good = xstrfmt("%s-*", terms->term_good);

	/*
	 * We cannot use terms->term_bad directly in
	 * for_each_glob_ref_in() and we have to append a '*' to it,
	 * otherwise for_each_glob_ref_in() will append '/' and '*'.
	 */
	char *bad = xstrfmt("%s*", terms->term_bad);

	/*
	 * It is important to reset the flags used by revision walks
	 * as the previous call to bisect_next_all() in turn
	 * sets up a revision walk.
	 */
	reset_revision_walk();
	init_revisions(revs, NULL);
	setup_revisions(0, NULL, revs, NULL);
	for_each_glob_ref_in(add_bisect_ref, bad, "refs/bisect/", &cb);
	cb.object_flags = UNINTERESTING;
	for_each_glob_ref_in(add_bisect_ref, good, "refs/bisect/", &cb);
	if (prepare_revision_walk(revs))
		res = error(_("revision walk setup failed\n"));

	free(good);
	free(bad);
	return res;
}

static int bisect_skipped_commits(struct bisect_terms *terms)
{
	int res;
	FILE *fp = NULL;
	struct rev_info revs;
	struct commit *commit;
	struct pretty_print_context pp = {0};
	struct strbuf commit_name = STRBUF_INIT;

	res = prepare_revs(terms, &revs);
	if (res)
		return res;

	fp = fopen(git_path_bisect_log(), "a");
	if (!fp)
		return error_errno(_("could not open '%s' for appending"),
				  git_path_bisect_log());

	if (fprintf(fp, "# only skipped commits left to test\n") < 0)
		return error_errno(_("failed to write to '%s'"), git_path_bisect_log());

	while ((commit = get_revision(&revs)) != NULL) {
		strbuf_reset(&commit_name);
		format_commit_message(commit, "%s",
				      &commit_name, &pp);
		fprintf(fp, "# possible first %s commit: [%s] %s\n",
			terms->term_bad, oid_to_hex(&commit->object.oid),
			commit_name.buf);
	}

	/*
	 * Reset the flags used by revision walks in case
	 * there is another revision walk after this one.
	 */
	reset_revision_walk();

	strbuf_release(&commit_name);
	fclose(fp);
	return 0;
}

static int bisect_successful(struct bisect_terms *terms)
{
	struct object_id oid;
	struct commit *commit;
	struct pretty_print_context pp = {0};
	struct strbuf commit_name = STRBUF_INIT;
	char *bad_ref = xstrfmt("refs/bisect/%s",terms->term_bad);
	int res;

	read_ref(bad_ref, &oid);
	commit = lookup_commit_reference_by_name(bad_ref);
	format_commit_message(commit, "%s", &commit_name, &pp);

	res = append_to_file(git_path_bisect_log(), "# first %s commit: [%s] %s\n",
			    terms->term_bad, oid_to_hex(&commit->object.oid),
			    commit_name.buf);

	strbuf_release(&commit_name);
	free(bad_ref);
	return res;
}

static enum bisect_error bisect_next(struct bisect_terms *terms, const char *prefix)
{
	enum bisect_error res;

	if (bisect_autostart(terms))
		return BISECT_FAILED;

	if (bisect_next_check(terms, terms->term_good))
		return BISECT_FAILED;

	/* Perform all bisection computation */
	res = bisect_next_all(the_repository, prefix);

	if (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND) {
		res = bisect_successful(terms);
		return res ? res : BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
	} else if (res == BISECT_ONLY_SKIPPED_LEFT) {
		res = bisect_skipped_commits(terms);
		return res ? res : BISECT_ONLY_SKIPPED_LEFT;
	}
	return res;
}

static enum bisect_error bisect_auto_next(struct bisect_terms *terms, const char *prefix)
{
	if (bisect_next_check(terms, NULL))
		return BISECT_OK;

	return bisect_next(terms, prefix);
}

static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
{
	int no_checkout = 0;
	int first_parent_only = 0;
	int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
	int flags, pathspec_pos, res = 0;
	struct string_list revs = STRING_LIST_INIT_DUP;
	struct string_list states = STRING_LIST_INIT_DUP;
	struct strbuf start_head = STRBUF_INIT;
	struct strbuf bisect_names = STRBUF_INIT;
	struct object_id head_oid;
	struct object_id oid;
	const char *head;

	if (is_bare_repository())
		no_checkout = 1;

	/*
	 * Check for one bad and then some good revisions
	 */
	for (i = 0; i < argc; i++) {
		if (!strcmp(argv[i], "--")) {
			has_double_dash = 1;
			break;
		}
	}

	for (i = 0; i < argc; i++) {
		const char *arg = argv[i];
		if (!strcmp(argv[i], "--")) {
			break;
		} else if (!strcmp(arg, "--no-checkout")) {
			no_checkout = 1;
		} else if (!strcmp(arg, "--first-parent")) {
			first_parent_only = 1;
		} else if (!strcmp(arg, "--term-good") ||
			 !strcmp(arg, "--term-old")) {
			i++;
			if (argc <= i)
				return error(_("'' is not a valid term"));
			must_write_terms = 1;
			free((void *) terms->term_good);
			terms->term_good = xstrdup(argv[i]);
		} else if (skip_prefix(arg, "--term-good=", &arg) ||
			   skip_prefix(arg, "--term-old=", &arg)) {
			must_write_terms = 1;
			free((void *) terms->term_good);
			terms->term_good = xstrdup(arg);
		} else if (!strcmp(arg, "--term-bad") ||
			 !strcmp(arg, "--term-new")) {
			i++;
			if (argc <= i)
				return error(_("'' is not a valid term"));
			must_write_terms = 1;
			free((void *) terms->term_bad);
			terms->term_bad = xstrdup(argv[i]);
		} else if (skip_prefix(arg, "--term-bad=", &arg) ||
			   skip_prefix(arg, "--term-new=", &arg)) {
			must_write_terms = 1;
			free((void *) terms->term_bad);
			terms->term_bad = xstrdup(arg);
		} else if (starts_with(arg, "--")) {
			return error(_("unrecognized option: '%s'"), arg);
		} else if (!get_oidf(&oid, "%s^{commit}", arg)) {
			string_list_append(&revs, oid_to_hex(&oid));
		} else if (has_double_dash) {
			die(_("'%s' does not appear to be a valid "
			      "revision"), arg);
		} else {
			break;
		}
	}
	pathspec_pos = i;

	/*
	 * The user ran "git bisect start <sha1> <sha1>", hence did not
	 * explicitly specify the terms, but we are already starting to
	 * set references named with the default terms, and won't be able
	 * to change afterwards.
	 */
	if (revs.nr)
		must_write_terms = 1;
	for (i = 0; i < revs.nr; i++) {
		if (bad_seen) {
			string_list_append(&states, terms->term_good);
		} else {
			bad_seen = 1;
			string_list_append(&states, terms->term_bad);
		}
	}

	/*
	 * Verify HEAD
	 */
	head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
	if (!head)
		if (get_oid("HEAD", &head_oid))
			return error(_("bad HEAD - I need a HEAD"));

	/*
	 * Check if we are bisecting
	 */
	if (!is_empty_or_missing_file(git_path_bisect_start())) {
		/* Reset to the rev from where we started */
		strbuf_read_file(&start_head, git_path_bisect_start(), 0);
		strbuf_trim(&start_head);
		if (!no_checkout) {
			struct strvec argv = STRVEC_INIT;

			strvec_pushl(&argv, "checkout", start_head.buf,
				     "--", NULL);
			if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
				res = error(_("checking out '%s' failed."
						 " Try 'git bisect start "
						 "<valid-branch>'."),
					       start_head.buf);
				goto finish;
			}
		}
	} else {
		/* Get the rev from where we start. */
		if (!get_oid(head, &head_oid) &&
		    !starts_with(head, "refs/heads/")) {
			strbuf_reset(&start_head);
			strbuf_addstr(&start_head, oid_to_hex(&head_oid));
		} else if (!get_oid(head, &head_oid) &&
			   skip_prefix(head, "refs/heads/", &head)) {
			/*
			 * This error message should only be triggered by
			 * cogito usage, and cogito users should understand
			 * it relates to cg-seek.
			 */
			if (!is_empty_or_missing_file(git_path_head_name()))
				return error(_("won't bisect on cg-seek'ed tree"));
			strbuf_addstr(&start_head, head);
		} else {
			return error(_("bad HEAD - strange symbolic ref"));
		}
	}

	/*
	 * Get rid of any old bisect state.
	 */
	if (bisect_clean_state())
		return -1;

	/*
	 * In case of mistaken revs or checkout error, or signals received,
	 * "bisect_auto_next" below may exit or misbehave.
	 * We have to trap this to be able to clean up using
	 * "bisect_clean_state".
	 */

	/*
	 * Write new start state
	 */
	write_file(git_path_bisect_start(), "%s\n", start_head.buf);

	if (first_parent_only)
		write_file(git_path_bisect_first_parent(), "\n");

	if (no_checkout) {
		if (get_oid(start_head.buf, &oid) < 0) {
			res = error(_("invalid ref: '%s'"), start_head.buf);
			goto finish;
		}
		if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
			       UPDATE_REFS_MSG_ON_ERR)) {
			res = -1;
			goto finish;
		}
	}

	if (pathspec_pos < argc - 1)
		sq_quote_argv(&bisect_names, argv + pathspec_pos);
	write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);

	for (i = 0; i < states.nr; i++)
		if (bisect_write(states.items[i].string,
				 revs.items[i].string, terms, 1)) {
			res = -1;
			goto finish;
		}

	if (must_write_terms && write_terms(terms->term_bad,
					    terms->term_good)) {
		res = -1;
		goto finish;
	}

	res = bisect_append_log_quoted(argv);
	if (res)
		res = -1;

finish:
	string_list_clear(&revs, 0);
	string_list_clear(&states, 0);
	strbuf_release(&start_head);
	strbuf_release(&bisect_names);
	return res;
}

static inline int file_is_not_empty(const char *path)
{
	return !is_empty_or_missing_file(path);
}

static int bisect_autostart(struct bisect_terms *terms)
{
	int res;
	const char *yesno;

	if (file_is_not_empty(git_path_bisect_start()))
		return 0;

	fprintf_ln(stderr, _("You need to start by \"git bisect "
			  "start\"\n"));

	if (!isatty(STDIN_FILENO))
		return -1;

	/*
	 * TRANSLATORS: Make sure to include [Y] and [n] in your
	 * translation. The program will only accept English input
	 * at this point.
	 */
	yesno = git_prompt(_("Do you want me to do it for you "
			     "[Y/n]? "), PROMPT_ECHO);
	res = tolower(*yesno) == 'n' ?
		-1 : bisect_start(terms, empty_strvec, 0);

	return res;
}

int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
{
	enum {
		NEXT_ALL = 1,
		WRITE_TERMS,
		BISECT_CLEAN_STATE,
		CHECK_EXPECTED_REVS,
		BISECT_RESET,
		BISECT_WRITE,
		CHECK_AND_SET_TERMS,
		BISECT_NEXT_CHECK,
		BISECT_TERMS,
		BISECT_START,
		BISECT_AUTOSTART,
		BISECT_NEXT,
		BISECT_AUTO_NEXT
	} cmdmode = 0;
	int res = 0, nolog = 0;
	struct option options[] = {
		OPT_CMDMODE(0, "next-all", &cmdmode,
			 N_("perform 'git bisect next'"), NEXT_ALL),
		OPT_CMDMODE(0, "write-terms", &cmdmode,
			 N_("write the terms to .git/BISECT_TERMS"), WRITE_TERMS),
		OPT_CMDMODE(0, "bisect-clean-state", &cmdmode,
			 N_("cleanup the bisection state"), BISECT_CLEAN_STATE),
		OPT_CMDMODE(0, "check-expected-revs", &cmdmode,
			 N_("check for expected revs"), CHECK_EXPECTED_REVS),
		OPT_CMDMODE(0, "bisect-reset", &cmdmode,
			 N_("reset the bisection state"), BISECT_RESET),
		OPT_CMDMODE(0, "bisect-write", &cmdmode,
			 N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
		OPT_CMDMODE(0, "check-and-set-terms", &cmdmode,
			 N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
		OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
			 N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
		OPT_CMDMODE(0, "bisect-terms", &cmdmode,
			 N_("print out the bisect terms"), BISECT_TERMS),
		OPT_CMDMODE(0, "bisect-start", &cmdmode,
			 N_("start the bisect session"), BISECT_START),
		OPT_CMDMODE(0, "bisect-next", &cmdmode,
			 N_("find the next bisection commit"), BISECT_NEXT),
		OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
			 N_("verify the next bisection state then checkout the next bisection commit"), BISECT_AUTO_NEXT),
		OPT_CMDMODE(0, "bisect-autostart", &cmdmode,
			 N_("start the bisection if it has not yet been started"), BISECT_AUTOSTART),
		OPT_BOOL(0, "no-log", &nolog,
			 N_("no log for BISECT_WRITE")),
		OPT_END()
	};
	struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };

	argc = parse_options(argc, argv, prefix, options,
			     git_bisect_helper_usage,
			     PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);

	if (!cmdmode)
		usage_with_options(git_bisect_helper_usage, options);

	switch (cmdmode) {
	case NEXT_ALL:
		res = bisect_next_all(the_repository, prefix);
		break;
	case WRITE_TERMS:
		if (argc != 2)
			return error(_("--write-terms requires two arguments"));
		return write_terms(argv[0], argv[1]);
	case BISECT_CLEAN_STATE:
		if (argc != 0)
			return error(_("--bisect-clean-state requires no arguments"));
		return bisect_clean_state();
	case CHECK_EXPECTED_REVS:
		check_expected_revs(argv, argc);
		return 0;
	case BISECT_RESET:
		if (argc > 1)
			return error(_("--bisect-reset requires either no argument or a commit"));
		return !!bisect_reset(argc ? argv[0] : NULL);
	case BISECT_WRITE:
		if (argc != 4 && argc != 5)
			return error(_("--bisect-write requires either 4 or 5 arguments"));
		set_terms(&terms, argv[3], argv[2]);
		res = bisect_write(argv[0], argv[1], &terms, nolog);
		break;
	case CHECK_AND_SET_TERMS:
		if (argc != 3)
			return error(_("--check-and-set-terms requires 3 arguments"));
		set_terms(&terms, argv[2], argv[1]);
		res = check_and_set_terms(&terms, argv[0]);
		break;
	case BISECT_NEXT_CHECK:
		if (argc != 2 && argc != 3)
			return error(_("--bisect-next-check requires 2 or 3 arguments"));
		set_terms(&terms, argv[1], argv[0]);
		res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
		break;
	case BISECT_TERMS:
		if (argc > 1)
			return error(_("--bisect-terms requires 0 or 1 argument"));
		res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
		break;
	case BISECT_START:
		set_terms(&terms, "bad", "good");
		res = bisect_start(&terms, argv, argc);
		break;
	case BISECT_NEXT:
		if (argc)
			return error(_("--bisect-next requires 0 arguments"));
		get_terms(&terms);
		res = bisect_next(&terms, prefix);
		break;
	case BISECT_AUTO_NEXT:
		if (argc)
			return error(_("--bisect-auto-next requires 0 arguments"));
		get_terms(&terms);
		res = bisect_auto_next(&terms, prefix);
		break;
	case BISECT_AUTOSTART:
		if (argc)
			return error(_("--bisect-autostart does not accept arguments"));
		set_terms(&terms, "bad", "good");
		res = bisect_autostart(&terms);
		break;
	default:
		BUG("unknown subcommand %d", cmdmode);
	}
	free_terms(&terms);

	/*
	 * Handle early success
	 * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
	 */
	if ((res == BISECT_INTERNAL_SUCCESS_MERGE_BASE) || (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND))
		res = BISECT_OK;

	return -res;
}