Merge branch 'vv/send-email-with-less-secure-apps-access'
[git] / 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 --bisect-reset [<commit>]"),
24         N_("git bisect--helper --bisect-write [--no-log] <state> <revision> <good_term> <bad_term>"),
25         N_("git bisect--helper --bisect-check-and-set-terms <command> <good_term> <bad_term>"),
26         N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
27         N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
28         N_("git bisect--helper --bisect-start [--term-{new,bad}=<term> --term-{old,good}=<term>]"
29                                             " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
30         N_("git bisect--helper --bisect-next"),
31         N_("git bisect--helper --bisect-auto-next"),
32         N_("git bisect--helper --bisect-state (bad|new) [<rev>]"),
33         N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
34         NULL
35 };
36
37 struct add_bisect_ref_data {
38         struct rev_info *revs;
39         unsigned int object_flags;
40 };
41
42 struct bisect_terms {
43         char *term_good;
44         char *term_bad;
45 };
46
47 static void free_terms(struct bisect_terms *terms)
48 {
49         FREE_AND_NULL(terms->term_good);
50         FREE_AND_NULL(terms->term_bad);
51 }
52
53 static void set_terms(struct bisect_terms *terms, const char *bad,
54                       const char *good)
55 {
56         free((void *)terms->term_good);
57         terms->term_good = xstrdup(good);
58         free((void *)terms->term_bad);
59         terms->term_bad = xstrdup(bad);
60 }
61
62 static const char vocab_bad[] = "bad|new";
63 static const char vocab_good[] = "good|old";
64
65 static int bisect_autostart(struct bisect_terms *terms);
66
67 /*
68  * Check whether the string `term` belongs to the set of strings
69  * included in the variable arguments.
70  */
71 LAST_ARG_MUST_BE_NULL
72 static int one_of(const char *term, ...)
73 {
74         int res = 0;
75         va_list matches;
76         const char *match;
77
78         va_start(matches, term);
79         while (!res && (match = va_arg(matches, const char *)))
80                 res = !strcmp(term, match);
81         va_end(matches);
82
83         return res;
84 }
85
86 /*
87  * return code BISECT_INTERNAL_SUCCESS_MERGE_BASE
88  * and BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND are codes
89  * that indicate special success.
90  */
91
92 static int is_bisect_success(enum bisect_error res)
93 {
94         return !res ||
95                 res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND ||
96                 res == BISECT_INTERNAL_SUCCESS_MERGE_BASE;
97 }
98
99 static int write_in_file(const char *path, const char *mode, const char *format, va_list args)
100 {
101         FILE *fp = NULL;
102         int res = 0;
103
104         if (strcmp(mode, "w") && strcmp(mode, "a"))
105                 BUG("write-in-file does not support '%s' mode", mode);
106         fp = fopen(path, mode);
107         if (!fp)
108                 return error_errno(_("cannot open file '%s' in mode '%s'"), path, mode);
109         res = vfprintf(fp, format, args);
110
111         if (res < 0) {
112                 int saved_errno = errno;
113                 fclose(fp);
114                 errno = saved_errno;
115                 return error_errno(_("could not write to file '%s'"), path);
116         }
117
118         return fclose(fp);
119 }
120
121 static int write_to_file(const char *path, const char *format, ...)
122 {
123         int res;
124         va_list args;
125
126         va_start(args, format);
127         res = write_in_file(path, "w", format, args);
128         va_end(args);
129
130         return res;
131 }
132
133 static int append_to_file(const char *path, const char *format, ...)
134 {
135         int res;
136         va_list args;
137
138         va_start(args, format);
139         res = write_in_file(path, "a", format, args);
140         va_end(args);
141
142         return res;
143 }
144
145 static int check_term_format(const char *term, const char *orig_term)
146 {
147         int res;
148         char *new_term = xstrfmt("refs/bisect/%s", term);
149
150         res = check_refname_format(new_term, 0);
151         free(new_term);
152
153         if (res)
154                 return error(_("'%s' is not a valid term"), term);
155
156         if (one_of(term, "help", "start", "skip", "next", "reset",
157                         "visualize", "view", "replay", "log", "run", "terms", NULL))
158                 return error(_("can't use the builtin command '%s' as a term"), term);
159
160         /*
161          * In theory, nothing prevents swapping completely good and bad,
162          * but this situation could be confusing and hasn't been tested
163          * enough. Forbid it for now.
164          */
165
166         if ((strcmp(orig_term, "bad") && one_of(term, "bad", "new", NULL)) ||
167                  (strcmp(orig_term, "good") && one_of(term, "good", "old", NULL)))
168                 return error(_("can't change the meaning of the term '%s'"), term);
169
170         return 0;
171 }
172
173 static int write_terms(const char *bad, const char *good)
174 {
175         int res;
176
177         if (!strcmp(bad, good))
178                 return error(_("please use two different terms"));
179
180         if (check_term_format(bad, "bad") || check_term_format(good, "good"))
181                 return -1;
182
183         res = write_to_file(git_path_bisect_terms(), "%s\n%s\n", bad, good);
184
185         return res;
186 }
187
188 static int bisect_reset(const char *commit)
189 {
190         struct strbuf branch = STRBUF_INIT;
191
192         if (!commit) {
193                 if (strbuf_read_file(&branch, git_path_bisect_start(), 0) < 1) {
194                         printf(_("We are not bisecting.\n"));
195                         return 0;
196                 }
197                 strbuf_rtrim(&branch);
198         } else {
199                 struct object_id oid;
200
201                 if (get_oid_commit(commit, &oid))
202                         return error(_("'%s' is not a valid commit"), commit);
203                 strbuf_addstr(&branch, commit);
204         }
205
206         if (!ref_exists("BISECT_HEAD")) {
207                 struct strvec argv = STRVEC_INIT;
208
209                 strvec_pushl(&argv, "checkout", branch.buf, "--", NULL);
210                 if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
211                         error(_("could not check out original"
212                                 " HEAD '%s'. Try 'git bisect"
213                                 " reset <commit>'."), branch.buf);
214                         strbuf_release(&branch);
215                         strvec_clear(&argv);
216                         return -1;
217                 }
218                 strvec_clear(&argv);
219         }
220
221         strbuf_release(&branch);
222         return bisect_clean_state();
223 }
224
225 static void log_commit(FILE *fp, char *fmt, const char *state,
226                        struct commit *commit)
227 {
228         struct pretty_print_context pp = {0};
229         struct strbuf commit_msg = STRBUF_INIT;
230         char *label = xstrfmt(fmt, state);
231
232         format_commit_message(commit, "%s", &commit_msg, &pp);
233
234         fprintf(fp, "# %s: [%s] %s\n", label, oid_to_hex(&commit->object.oid),
235                 commit_msg.buf);
236
237         strbuf_release(&commit_msg);
238         free(label);
239 }
240
241 static int bisect_write(const char *state, const char *rev,
242                         const struct bisect_terms *terms, int nolog)
243 {
244         struct strbuf tag = STRBUF_INIT;
245         struct object_id oid;
246         struct commit *commit;
247         FILE *fp = NULL;
248         int res = 0;
249
250         if (!strcmp(state, terms->term_bad)) {
251                 strbuf_addf(&tag, "refs/bisect/%s", state);
252         } else if (one_of(state, terms->term_good, "skip", NULL)) {
253                 strbuf_addf(&tag, "refs/bisect/%s-%s", state, rev);
254         } else {
255                 res = error(_("Bad bisect_write argument: %s"), state);
256                 goto finish;
257         }
258
259         if (get_oid(rev, &oid)) {
260                 res = error(_("couldn't get the oid of the rev '%s'"), rev);
261                 goto finish;
262         }
263
264         if (update_ref(NULL, tag.buf, &oid, NULL, 0,
265                        UPDATE_REFS_MSG_ON_ERR)) {
266                 res = -1;
267                 goto finish;
268         }
269
270         fp = fopen(git_path_bisect_log(), "a");
271         if (!fp) {
272                 res = error_errno(_("couldn't open the file '%s'"), git_path_bisect_log());
273                 goto finish;
274         }
275
276         commit = lookup_commit_reference(the_repository, &oid);
277         log_commit(fp, "%s", state, commit);
278
279         if (!nolog)
280                 fprintf(fp, "git bisect %s %s\n", state, rev);
281
282 finish:
283         if (fp)
284                 fclose(fp);
285         strbuf_release(&tag);
286         return res;
287 }
288
289 static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
290 {
291         int has_term_file = !is_empty_or_missing_file(git_path_bisect_terms());
292
293         if (one_of(cmd, "skip", "start", "terms", NULL))
294                 return 0;
295
296         if (has_term_file && strcmp(cmd, terms->term_bad) &&
297             strcmp(cmd, terms->term_good))
298                 return error(_("Invalid command: you're currently in a "
299                                 "%s/%s bisect"), terms->term_bad,
300                                 terms->term_good);
301
302         if (!has_term_file) {
303                 if (one_of(cmd, "bad", "good", NULL)) {
304                         set_terms(terms, "bad", "good");
305                         return write_terms(terms->term_bad, terms->term_good);
306                 }
307                 if (one_of(cmd, "new", "old", NULL)) {
308                         set_terms(terms, "new", "old");
309                         return write_terms(terms->term_bad, terms->term_good);
310                 }
311         }
312
313         return 0;
314 }
315
316 static int mark_good(const char *refname, const struct object_id *oid,
317                      int flag, void *cb_data)
318 {
319         int *m_good = (int *)cb_data;
320         *m_good = 0;
321         return 1;
322 }
323
324 static const char need_bad_and_good_revision_warning[] =
325         N_("You need to give me at least one %s and %s revision.\n"
326            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
327
328 static const char need_bisect_start_warning[] =
329         N_("You need to start by \"git bisect start\".\n"
330            "You then need to give me at least one %s and %s revision.\n"
331            "You can use \"git bisect %s\" and \"git bisect %s\" for that.");
332
333 static int decide_next(const struct bisect_terms *terms,
334                        const char *current_term, int missing_good,
335                        int missing_bad)
336 {
337         if (!missing_good && !missing_bad)
338                 return 0;
339         if (!current_term)
340                 return -1;
341
342         if (missing_good && !missing_bad &&
343             !strcmp(current_term, terms->term_good)) {
344                 char *yesno;
345                 /*
346                  * have bad (or new) but not good (or old). We could bisect
347                  * although this is less optimum.
348                  */
349                 warning(_("bisecting only with a %s commit"), terms->term_bad);
350                 if (!isatty(0))
351                         return 0;
352                 /*
353                  * TRANSLATORS: Make sure to include [Y] and [n] in your
354                  * translation. The program will only accept English input
355                  * at this point.
356                  */
357                 yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
358                 if (starts_with(yesno, "N") || starts_with(yesno, "n"))
359                         return -1;
360                 return 0;
361         }
362
363         if (!is_empty_or_missing_file(git_path_bisect_start()))
364                 return error(_(need_bad_and_good_revision_warning),
365                              vocab_bad, vocab_good, vocab_bad, vocab_good);
366         else
367                 return error(_(need_bisect_start_warning),
368                              vocab_good, vocab_bad, vocab_good, vocab_bad);
369 }
370
371 static int bisect_next_check(const struct bisect_terms *terms,
372                              const char *current_term)
373 {
374         int missing_good = 1, missing_bad = 1;
375         char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
376         char *good_glob = xstrfmt("%s-*", terms->term_good);
377
378         if (ref_exists(bad_ref))
379                 missing_bad = 0;
380
381         for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
382                              (void *) &missing_good);
383
384         free(good_glob);
385         free(bad_ref);
386
387         return decide_next(terms, current_term, missing_good, missing_bad);
388 }
389
390 static int get_terms(struct bisect_terms *terms)
391 {
392         struct strbuf str = STRBUF_INIT;
393         FILE *fp = NULL;
394         int res = 0;
395
396         fp = fopen(git_path_bisect_terms(), "r");
397         if (!fp) {
398                 res = -1;
399                 goto finish;
400         }
401
402         free_terms(terms);
403         strbuf_getline_lf(&str, fp);
404         terms->term_bad = strbuf_detach(&str, NULL);
405         strbuf_getline_lf(&str, fp);
406         terms->term_good = strbuf_detach(&str, NULL);
407
408 finish:
409         if (fp)
410                 fclose(fp);
411         strbuf_release(&str);
412         return res;
413 }
414
415 static int bisect_terms(struct bisect_terms *terms, const char *option)
416 {
417         if (get_terms(terms))
418                 return error(_("no terms defined"));
419
420         if (option == NULL) {
421                 printf(_("Your current terms are %s for the old state\n"
422                          "and %s for the new state.\n"),
423                        terms->term_good, terms->term_bad);
424                 return 0;
425         }
426         if (one_of(option, "--term-good", "--term-old", NULL))
427                 printf("%s\n", terms->term_good);
428         else if (one_of(option, "--term-bad", "--term-new", NULL))
429                 printf("%s\n", terms->term_bad);
430         else
431                 return error(_("invalid argument %s for 'git bisect terms'.\n"
432                                "Supported options are: "
433                                "--term-good|--term-old and "
434                                "--term-bad|--term-new."), option);
435
436         return 0;
437 }
438
439 static int bisect_append_log_quoted(const char **argv)
440 {
441         int res = 0;
442         FILE *fp = fopen(git_path_bisect_log(), "a");
443         struct strbuf orig_args = STRBUF_INIT;
444
445         if (!fp)
446                 return -1;
447
448         if (fprintf(fp, "git bisect start") < 1) {
449                 res = -1;
450                 goto finish;
451         }
452
453         sq_quote_argv(&orig_args, argv);
454         if (fprintf(fp, "%s\n", orig_args.buf) < 1)
455                 res = -1;
456
457 finish:
458         fclose(fp);
459         strbuf_release(&orig_args);
460         return res;
461 }
462
463 static int add_bisect_ref(const char *refname, const struct object_id *oid,
464                           int flags, void *cb)
465 {
466         struct add_bisect_ref_data *data = cb;
467
468         add_pending_oid(data->revs, refname, oid, data->object_flags);
469
470         return 0;
471 }
472
473 static int prepare_revs(struct bisect_terms *terms, struct rev_info *revs)
474 {
475         int res = 0;
476         struct add_bisect_ref_data cb = { revs };
477         char *good = xstrfmt("%s-*", terms->term_good);
478
479         /*
480          * We cannot use terms->term_bad directly in
481          * for_each_glob_ref_in() and we have to append a '*' to it,
482          * otherwise for_each_glob_ref_in() will append '/' and '*'.
483          */
484         char *bad = xstrfmt("%s*", terms->term_bad);
485
486         /*
487          * It is important to reset the flags used by revision walks
488          * as the previous call to bisect_next_all() in turn
489          * sets up a revision walk.
490          */
491         reset_revision_walk();
492         init_revisions(revs, NULL);
493         setup_revisions(0, NULL, revs, NULL);
494         for_each_glob_ref_in(add_bisect_ref, bad, "refs/bisect/", &cb);
495         cb.object_flags = UNINTERESTING;
496         for_each_glob_ref_in(add_bisect_ref, good, "refs/bisect/", &cb);
497         if (prepare_revision_walk(revs))
498                 res = error(_("revision walk setup failed\n"));
499
500         free(good);
501         free(bad);
502         return res;
503 }
504
505 static int bisect_skipped_commits(struct bisect_terms *terms)
506 {
507         int res;
508         FILE *fp = NULL;
509         struct rev_info revs;
510         struct commit *commit;
511         struct pretty_print_context pp = {0};
512         struct strbuf commit_name = STRBUF_INIT;
513
514         res = prepare_revs(terms, &revs);
515         if (res)
516                 return res;
517
518         fp = fopen(git_path_bisect_log(), "a");
519         if (!fp)
520                 return error_errno(_("could not open '%s' for appending"),
521                                   git_path_bisect_log());
522
523         if (fprintf(fp, "# only skipped commits left to test\n") < 0)
524                 return error_errno(_("failed to write to '%s'"), git_path_bisect_log());
525
526         while ((commit = get_revision(&revs)) != NULL) {
527                 strbuf_reset(&commit_name);
528                 format_commit_message(commit, "%s",
529                                       &commit_name, &pp);
530                 fprintf(fp, "# possible first %s commit: [%s] %s\n",
531                         terms->term_bad, oid_to_hex(&commit->object.oid),
532                         commit_name.buf);
533         }
534
535         /*
536          * Reset the flags used by revision walks in case
537          * there is another revision walk after this one.
538          */
539         reset_revision_walk();
540
541         strbuf_release(&commit_name);
542         fclose(fp);
543         return 0;
544 }
545
546 static int bisect_successful(struct bisect_terms *terms)
547 {
548         struct object_id oid;
549         struct commit *commit;
550         struct pretty_print_context pp = {0};
551         struct strbuf commit_name = STRBUF_INIT;
552         char *bad_ref = xstrfmt("refs/bisect/%s",terms->term_bad);
553         int res;
554
555         read_ref(bad_ref, &oid);
556         commit = lookup_commit_reference_by_name(bad_ref);
557         format_commit_message(commit, "%s", &commit_name, &pp);
558
559         res = append_to_file(git_path_bisect_log(), "# first %s commit: [%s] %s\n",
560                             terms->term_bad, oid_to_hex(&commit->object.oid),
561                             commit_name.buf);
562
563         strbuf_release(&commit_name);
564         free(bad_ref);
565         return res;
566 }
567
568 static enum bisect_error bisect_next(struct bisect_terms *terms, const char *prefix)
569 {
570         enum bisect_error res;
571
572         if (bisect_autostart(terms))
573                 return BISECT_FAILED;
574
575         if (bisect_next_check(terms, terms->term_good))
576                 return BISECT_FAILED;
577
578         /* Perform all bisection computation */
579         res = bisect_next_all(the_repository, prefix);
580
581         if (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND) {
582                 res = bisect_successful(terms);
583                 return res ? res : BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
584         } else if (res == BISECT_ONLY_SKIPPED_LEFT) {
585                 res = bisect_skipped_commits(terms);
586                 return res ? res : BISECT_ONLY_SKIPPED_LEFT;
587         }
588         return res;
589 }
590
591 static enum bisect_error bisect_auto_next(struct bisect_terms *terms, const char *prefix)
592 {
593         if (bisect_next_check(terms, NULL))
594                 return BISECT_OK;
595
596         return bisect_next(terms, prefix);
597 }
598
599 static enum bisect_error bisect_start(struct bisect_terms *terms, const char **argv, int argc)
600 {
601         int no_checkout = 0;
602         int first_parent_only = 0;
603         int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
604         int flags, pathspec_pos;
605         enum bisect_error res = BISECT_OK;
606         struct string_list revs = STRING_LIST_INIT_DUP;
607         struct string_list states = STRING_LIST_INIT_DUP;
608         struct strbuf start_head = STRBUF_INIT;
609         struct strbuf bisect_names = STRBUF_INIT;
610         struct object_id head_oid;
611         struct object_id oid;
612         const char *head;
613
614         if (is_bare_repository())
615                 no_checkout = 1;
616
617         /*
618          * Check for one bad and then some good revisions
619          */
620         for (i = 0; i < argc; i++) {
621                 if (!strcmp(argv[i], "--")) {
622                         has_double_dash = 1;
623                         break;
624                 }
625         }
626
627         for (i = 0; i < argc; i++) {
628                 const char *arg = argv[i];
629                 if (!strcmp(argv[i], "--")) {
630                         break;
631                 } else if (!strcmp(arg, "--no-checkout")) {
632                         no_checkout = 1;
633                 } else if (!strcmp(arg, "--first-parent")) {
634                         first_parent_only = 1;
635                 } else if (!strcmp(arg, "--term-good") ||
636                          !strcmp(arg, "--term-old")) {
637                         i++;
638                         if (argc <= i)
639                                 return error(_("'' is not a valid term"));
640                         must_write_terms = 1;
641                         free((void *) terms->term_good);
642                         terms->term_good = xstrdup(argv[i]);
643                 } else if (skip_prefix(arg, "--term-good=", &arg) ||
644                            skip_prefix(arg, "--term-old=", &arg)) {
645                         must_write_terms = 1;
646                         free((void *) terms->term_good);
647                         terms->term_good = xstrdup(arg);
648                 } else if (!strcmp(arg, "--term-bad") ||
649                          !strcmp(arg, "--term-new")) {
650                         i++;
651                         if (argc <= i)
652                                 return error(_("'' is not a valid term"));
653                         must_write_terms = 1;
654                         free((void *) terms->term_bad);
655                         terms->term_bad = xstrdup(argv[i]);
656                 } else if (skip_prefix(arg, "--term-bad=", &arg) ||
657                            skip_prefix(arg, "--term-new=", &arg)) {
658                         must_write_terms = 1;
659                         free((void *) terms->term_bad);
660                         terms->term_bad = xstrdup(arg);
661                 } else if (starts_with(arg, "--")) {
662                         return error(_("unrecognized option: '%s'"), arg);
663                 } else if (!get_oidf(&oid, "%s^{commit}", arg)) {
664                         string_list_append(&revs, oid_to_hex(&oid));
665                 } else if (has_double_dash) {
666                         die(_("'%s' does not appear to be a valid "
667                               "revision"), arg);
668                 } else {
669                         break;
670                 }
671         }
672         pathspec_pos = i;
673
674         /*
675          * The user ran "git bisect start <sha1> <sha1>", hence did not
676          * explicitly specify the terms, but we are already starting to
677          * set references named with the default terms, and won't be able
678          * to change afterwards.
679          */
680         if (revs.nr)
681                 must_write_terms = 1;
682         for (i = 0; i < revs.nr; i++) {
683                 if (bad_seen) {
684                         string_list_append(&states, terms->term_good);
685                 } else {
686                         bad_seen = 1;
687                         string_list_append(&states, terms->term_bad);
688                 }
689         }
690
691         /*
692          * Verify HEAD
693          */
694         head = resolve_ref_unsafe("HEAD", 0, &head_oid, &flags);
695         if (!head)
696                 if (get_oid("HEAD", &head_oid))
697                         return error(_("bad HEAD - I need a HEAD"));
698
699         /*
700          * Check if we are bisecting
701          */
702         if (!is_empty_or_missing_file(git_path_bisect_start())) {
703                 /* Reset to the rev from where we started */
704                 strbuf_read_file(&start_head, git_path_bisect_start(), 0);
705                 strbuf_trim(&start_head);
706                 if (!no_checkout) {
707                         struct strvec argv = STRVEC_INIT;
708
709                         strvec_pushl(&argv, "checkout", start_head.buf,
710                                      "--", NULL);
711                         if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
712                                 res = error(_("checking out '%s' failed."
713                                                  " Try 'git bisect start "
714                                                  "<valid-branch>'."),
715                                                start_head.buf);
716                                 goto finish;
717                         }
718                 }
719         } else {
720                 /* Get the rev from where we start. */
721                 if (!get_oid(head, &head_oid) &&
722                     !starts_with(head, "refs/heads/")) {
723                         strbuf_reset(&start_head);
724                         strbuf_addstr(&start_head, oid_to_hex(&head_oid));
725                 } else if (!get_oid(head, &head_oid) &&
726                            skip_prefix(head, "refs/heads/", &head)) {
727                         /*
728                          * This error message should only be triggered by
729                          * cogito usage, and cogito users should understand
730                          * it relates to cg-seek.
731                          */
732                         if (!is_empty_or_missing_file(git_path_head_name()))
733                                 return error(_("won't bisect on cg-seek'ed tree"));
734                         strbuf_addstr(&start_head, head);
735                 } else {
736                         return error(_("bad HEAD - strange symbolic ref"));
737                 }
738         }
739
740         /*
741          * Get rid of any old bisect state.
742          */
743         if (bisect_clean_state())
744                 return BISECT_FAILED;
745
746         /*
747          * Write new start state
748          */
749         write_file(git_path_bisect_start(), "%s\n", start_head.buf);
750
751         if (first_parent_only)
752                 write_file(git_path_bisect_first_parent(), "\n");
753
754         if (no_checkout) {
755                 if (get_oid(start_head.buf, &oid) < 0) {
756                         res = error(_("invalid ref: '%s'"), start_head.buf);
757                         goto finish;
758                 }
759                 if (update_ref(NULL, "BISECT_HEAD", &oid, NULL, 0,
760                                UPDATE_REFS_MSG_ON_ERR)) {
761                         res = BISECT_FAILED;
762                         goto finish;
763                 }
764         }
765
766         if (pathspec_pos < argc - 1)
767                 sq_quote_argv(&bisect_names, argv + pathspec_pos);
768         write_file(git_path_bisect_names(), "%s\n", bisect_names.buf);
769
770         for (i = 0; i < states.nr; i++)
771                 if (bisect_write(states.items[i].string,
772                                  revs.items[i].string, terms, 1)) {
773                         res = BISECT_FAILED;
774                         goto finish;
775                 }
776
777         if (must_write_terms && write_terms(terms->term_bad,
778                                             terms->term_good)) {
779                 res = BISECT_FAILED;
780                 goto finish;
781         }
782
783         res = bisect_append_log_quoted(argv);
784         if (res)
785                 res = BISECT_FAILED;
786
787 finish:
788         string_list_clear(&revs, 0);
789         string_list_clear(&states, 0);
790         strbuf_release(&start_head);
791         strbuf_release(&bisect_names);
792         if (res)
793                 return res;
794
795         res = bisect_auto_next(terms, NULL);
796         if (!is_bisect_success(res))
797                 bisect_clean_state();
798         return res;
799 }
800
801 static inline int file_is_not_empty(const char *path)
802 {
803         return !is_empty_or_missing_file(path);
804 }
805
806 static int bisect_autostart(struct bisect_terms *terms)
807 {
808         int res;
809         const char *yesno;
810
811         if (file_is_not_empty(git_path_bisect_start()))
812                 return 0;
813
814         fprintf_ln(stderr, _("You need to start by \"git bisect "
815                           "start\"\n"));
816
817         if (!isatty(STDIN_FILENO))
818                 return -1;
819
820         /*
821          * TRANSLATORS: Make sure to include [Y] and [n] in your
822          * translation. The program will only accept English input
823          * at this point.
824          */
825         yesno = git_prompt(_("Do you want me to do it for you "
826                              "[Y/n]? "), PROMPT_ECHO);
827         res = tolower(*yesno) == 'n' ?
828                 -1 : bisect_start(terms, empty_strvec, 0);
829
830         return res;
831 }
832
833 static enum bisect_error bisect_state(struct bisect_terms *terms, const char **argv,
834                                       int argc)
835 {
836         const char *state;
837         int i, verify_expected = 1;
838         struct object_id oid, expected;
839         struct strbuf buf = STRBUF_INIT;
840         struct oid_array revs = OID_ARRAY_INIT;
841
842         if (!argc)
843                 return error(_("Please call `--bisect-state` with at least one argument"));
844
845         if (bisect_autostart(terms))
846                 return BISECT_FAILED;
847
848         state = argv[0];
849         if (check_and_set_terms(terms, state) ||
850             !one_of(state, terms->term_good, terms->term_bad, "skip", NULL))
851                 return BISECT_FAILED;
852
853         argv++;
854         argc--;
855         if (argc > 1 && !strcmp(state, terms->term_bad))
856                 return error(_("'git bisect %s' can take only one argument."), terms->term_bad);
857
858         if (argc == 0) {
859                 const char *head = "BISECT_HEAD";
860                 enum get_oid_result res_head = get_oid(head, &oid);
861
862                 if (res_head == MISSING_OBJECT) {
863                         head = "HEAD";
864                         res_head = get_oid(head, &oid);
865                 }
866
867                 if (res_head)
868                         error(_("Bad rev input: %s"), head);
869                 oid_array_append(&revs, &oid);
870         }
871
872         /*
873          * All input revs must be checked before executing bisect_write()
874          * to discard junk revs.
875          */
876
877         for (; argc; argc--, argv++) {
878                 if (get_oid(*argv, &oid)){
879                         error(_("Bad rev input: %s"), *argv);
880                         oid_array_clear(&revs);
881                         return BISECT_FAILED;
882                 }
883                 oid_array_append(&revs, &oid);
884         }
885
886         if (strbuf_read_file(&buf, git_path_bisect_expected_rev(), 0) < the_hash_algo->hexsz ||
887             get_oid_hex(buf.buf, &expected) < 0)
888                 verify_expected = 0; /* Ignore invalid file contents */
889         strbuf_release(&buf);
890
891         for (i = 0; i < revs.nr; i++) {
892                 if (bisect_write(state, oid_to_hex(&revs.oid[i]), terms, 0)) {
893                         oid_array_clear(&revs);
894                         return BISECT_FAILED;
895                 }
896                 if (verify_expected && !oideq(&revs.oid[i], &expected)) {
897                         unlink_or_warn(git_path_bisect_ancestors_ok());
898                         unlink_or_warn(git_path_bisect_expected_rev());
899                         verify_expected = 0;
900                 }
901         }
902
903         oid_array_clear(&revs);
904         return bisect_auto_next(terms, NULL);
905 }
906
907 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
908 {
909         enum {
910                 BISECT_RESET = 1,
911                 BISECT_WRITE,
912                 CHECK_AND_SET_TERMS,
913                 BISECT_NEXT_CHECK,
914                 BISECT_TERMS,
915                 BISECT_START,
916                 BISECT_AUTOSTART,
917                 BISECT_NEXT,
918                 BISECT_AUTO_NEXT,
919                 BISECT_STATE
920         } cmdmode = 0;
921         int res = 0, nolog = 0;
922         struct option options[] = {
923                 OPT_CMDMODE(0, "bisect-reset", &cmdmode,
924                          N_("reset the bisection state"), BISECT_RESET),
925                 OPT_CMDMODE(0, "bisect-write", &cmdmode,
926                          N_("write out the bisection state in BISECT_LOG"), BISECT_WRITE),
927                 OPT_CMDMODE(0, "check-and-set-terms", &cmdmode,
928                          N_("check and set terms in a bisection state"), CHECK_AND_SET_TERMS),
929                 OPT_CMDMODE(0, "bisect-next-check", &cmdmode,
930                          N_("check whether bad or good terms exist"), BISECT_NEXT_CHECK),
931                 OPT_CMDMODE(0, "bisect-terms", &cmdmode,
932                          N_("print out the bisect terms"), BISECT_TERMS),
933                 OPT_CMDMODE(0, "bisect-start", &cmdmode,
934                          N_("start the bisect session"), BISECT_START),
935                 OPT_CMDMODE(0, "bisect-next", &cmdmode,
936                          N_("find the next bisection commit"), BISECT_NEXT),
937                 OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
938                          N_("verify the next bisection state then checkout the next bisection commit"), BISECT_AUTO_NEXT),
939                 OPT_CMDMODE(0, "bisect-state", &cmdmode,
940                          N_("mark the state of ref (or refs)"), BISECT_STATE),
941                 OPT_BOOL(0, "no-log", &nolog,
942                          N_("no log for BISECT_WRITE")),
943                 OPT_END()
944         };
945         struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
946
947         argc = parse_options(argc, argv, prefix, options,
948                              git_bisect_helper_usage,
949                              PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
950
951         if (!cmdmode)
952                 usage_with_options(git_bisect_helper_usage, options);
953
954         switch (cmdmode) {
955         case BISECT_RESET:
956                 if (argc > 1)
957                         return error(_("--bisect-reset requires either no argument or a commit"));
958                 return !!bisect_reset(argc ? argv[0] : NULL);
959         case BISECT_WRITE:
960                 if (argc != 4 && argc != 5)
961                         return error(_("--bisect-write requires either 4 or 5 arguments"));
962                 set_terms(&terms, argv[3], argv[2]);
963                 res = bisect_write(argv[0], argv[1], &terms, nolog);
964                 break;
965         case CHECK_AND_SET_TERMS:
966                 if (argc != 3)
967                         return error(_("--check-and-set-terms requires 3 arguments"));
968                 set_terms(&terms, argv[2], argv[1]);
969                 res = check_and_set_terms(&terms, argv[0]);
970                 break;
971         case BISECT_NEXT_CHECK:
972                 if (argc != 2 && argc != 3)
973                         return error(_("--bisect-next-check requires 2 or 3 arguments"));
974                 set_terms(&terms, argv[1], argv[0]);
975                 res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
976                 break;
977         case BISECT_TERMS:
978                 if (argc > 1)
979                         return error(_("--bisect-terms requires 0 or 1 argument"));
980                 res = bisect_terms(&terms, argc == 1 ? argv[0] : NULL);
981                 break;
982         case BISECT_START:
983                 set_terms(&terms, "bad", "good");
984                 res = bisect_start(&terms, argv, argc);
985                 break;
986         case BISECT_NEXT:
987                 if (argc)
988                         return error(_("--bisect-next requires 0 arguments"));
989                 get_terms(&terms);
990                 res = bisect_next(&terms, prefix);
991                 break;
992         case BISECT_AUTO_NEXT:
993                 if (argc)
994                         return error(_("--bisect-auto-next requires 0 arguments"));
995                 get_terms(&terms);
996                 res = bisect_auto_next(&terms, prefix);
997                 break;
998         case BISECT_STATE:
999                 set_terms(&terms, "bad", "good");
1000                 get_terms(&terms);
1001                 res = bisect_state(&terms, argv, argc);
1002                 break;
1003         default:
1004                 BUG("unknown subcommand %d", cmdmode);
1005         }
1006         free_terms(&terms);
1007
1008         /*
1009          * Handle early success
1010          * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
1011          */
1012         if ((res == BISECT_INTERNAL_SUCCESS_MERGE_BASE) || (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND))
1013                 res = BISECT_OK;
1014
1015         return -res;
1016 }