Merge branch 'jt/http-redact-cookies' into maint
[git.git] / bisect.c
blobf6d05bd66f42bd9874a08f5585ae99337d22dad5
1 #include "cache.h"
2 #include "config.h"
3 #include "commit.h"
4 #include "diff.h"
5 #include "revision.h"
6 #include "refs.h"
7 #include "list-objects.h"
8 #include "quote.h"
9 #include "sha1-lookup.h"
10 #include "run-command.h"
11 #include "log-tree.h"
12 #include "bisect.h"
13 #include "sha1-array.h"
14 #include "argv-array.h"
16 static struct oid_array good_revs;
17 static struct oid_array skipped_revs;
19 static struct object_id *current_bad_oid;
21 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
22 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
24 static const char *term_bad;
25 static const char *term_good;
27 /* Remember to update object flag allocation in object.h */
28 #define COUNTED (1u<<16)
31 * This is a truly stupid algorithm, but it's only
32 * used for bisection, and we just don't care enough.
34 * We care just barely enough to avoid recursing for
35 * non-merge entries.
37 static int count_distance(struct commit_list *entry)
39 int nr = 0;
41 while (entry) {
42 struct commit *commit = entry->item;
43 struct commit_list *p;
45 if (commit->object.flags & (UNINTERESTING | COUNTED))
46 break;
47 if (!(commit->object.flags & TREESAME))
48 nr++;
49 commit->object.flags |= COUNTED;
50 p = commit->parents;
51 entry = p;
52 if (p) {
53 p = p->next;
54 while (p) {
55 nr += count_distance(p);
56 p = p->next;
61 return nr;
64 static void clear_distance(struct commit_list *list)
66 while (list) {
67 struct commit *commit = list->item;
68 commit->object.flags &= ~COUNTED;
69 list = list->next;
73 #define DEBUG_BISECT 0
75 static inline int weight(struct commit_list *elem)
77 return *((int*)(elem->item->util));
80 static inline void weight_set(struct commit_list *elem, int weight)
82 *((int*)(elem->item->util)) = weight;
85 static int count_interesting_parents(struct commit *commit)
87 struct commit_list *p;
88 int count;
90 for (count = 0, p = commit->parents; p; p = p->next) {
91 if (p->item->object.flags & UNINTERESTING)
92 continue;
93 count++;
95 return count;
98 static inline int halfway(struct commit_list *p, int nr)
101 * Don't short-cut something we are not going to return!
103 if (p->item->object.flags & TREESAME)
104 return 0;
105 if (DEBUG_BISECT)
106 return 0;
108 * 2 and 3 are halfway of 5.
109 * 3 is halfway of 6 but 2 and 4 are not.
111 switch (2 * weight(p) - nr) {
112 case -1: case 0: case 1:
113 return 1;
114 default:
115 return 0;
119 #if !DEBUG_BISECT
120 #define show_list(a,b,c,d) do { ; } while (0)
121 #else
122 static void show_list(const char *debug, int counted, int nr,
123 struct commit_list *list)
125 struct commit_list *p;
127 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
129 for (p = list; p; p = p->next) {
130 struct commit_list *pp;
131 struct commit *commit = p->item;
132 unsigned flags = commit->object.flags;
133 enum object_type type;
134 unsigned long size;
135 char *buf = read_sha1_file(commit->object.oid.hash, &type, &size);
136 const char *subject_start;
137 int subject_len;
139 fprintf(stderr, "%c%c%c ",
140 (flags & TREESAME) ? ' ' : 'T',
141 (flags & UNINTERESTING) ? 'U' : ' ',
142 (flags & COUNTED) ? 'C' : ' ');
143 if (commit->util)
144 fprintf(stderr, "%3d", weight(p));
145 else
146 fprintf(stderr, "---");
147 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.oid.hash));
148 for (pp = commit->parents; pp; pp = pp->next)
149 fprintf(stderr, " %.*s", 8,
150 sha1_to_hex(pp->item->object.oid.hash));
152 subject_len = find_commit_subject(buf, &subject_start);
153 if (subject_len)
154 fprintf(stderr, " %.*s", subject_len, subject_start);
155 fprintf(stderr, "\n");
158 #endif /* DEBUG_BISECT */
160 static struct commit_list *best_bisection(struct commit_list *list, int nr)
162 struct commit_list *p, *best;
163 int best_distance = -1;
165 best = list;
166 for (p = list; p; p = p->next) {
167 int distance;
168 unsigned flags = p->item->object.flags;
170 if (flags & TREESAME)
171 continue;
172 distance = weight(p);
173 if (nr - distance < distance)
174 distance = nr - distance;
175 if (distance > best_distance) {
176 best = p;
177 best_distance = distance;
181 return best;
184 struct commit_dist {
185 struct commit *commit;
186 int distance;
189 static int compare_commit_dist(const void *a_, const void *b_)
191 struct commit_dist *a, *b;
193 a = (struct commit_dist *)a_;
194 b = (struct commit_dist *)b_;
195 if (a->distance != b->distance)
196 return b->distance - a->distance; /* desc sort */
197 return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
200 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
202 struct commit_list *p;
203 struct commit_dist *array = xcalloc(nr, sizeof(*array));
204 struct strbuf buf = STRBUF_INIT;
205 int cnt, i;
207 for (p = list, cnt = 0; p; p = p->next) {
208 int distance;
209 unsigned flags = p->item->object.flags;
211 if (flags & TREESAME)
212 continue;
213 distance = weight(p);
214 if (nr - distance < distance)
215 distance = nr - distance;
216 array[cnt].commit = p->item;
217 array[cnt].distance = distance;
218 cnt++;
220 QSORT(array, cnt, compare_commit_dist);
221 for (p = list, i = 0; i < cnt; i++) {
222 struct object *obj = &(array[i].commit->object);
224 strbuf_reset(&buf);
225 strbuf_addf(&buf, "dist=%d", array[i].distance);
226 add_name_decoration(DECORATION_NONE, buf.buf, obj);
228 p->item = array[i].commit;
229 if (i < cnt - 1)
230 p = p->next;
232 if (p) {
233 free_commit_list(p->next);
234 p->next = NULL;
236 strbuf_release(&buf);
237 free(array);
238 return list;
242 * zero or positive weight is the number of interesting commits it can
243 * reach, including itself. Especially, weight = 0 means it does not
244 * reach any tree-changing commits (e.g. just above uninteresting one
245 * but traversal is with pathspec).
247 * weight = -1 means it has one parent and its distance is yet to
248 * be computed.
250 * weight = -2 means it has more than one parent and its distance is
251 * unknown. After running count_distance() first, they will get zero
252 * or positive distance.
254 static struct commit_list *do_find_bisection(struct commit_list *list,
255 int nr, int *weights,
256 int find_all)
258 int n, counted;
259 struct commit_list *p;
261 counted = 0;
263 for (n = 0, p = list; p; p = p->next) {
264 struct commit *commit = p->item;
265 unsigned flags = commit->object.flags;
267 p->item->util = &weights[n++];
268 switch (count_interesting_parents(commit)) {
269 case 0:
270 if (!(flags & TREESAME)) {
271 weight_set(p, 1);
272 counted++;
273 show_list("bisection 2 count one",
274 counted, nr, list);
277 * otherwise, it is known not to reach any
278 * tree-changing commit and gets weight 0.
280 break;
281 case 1:
282 weight_set(p, -1);
283 break;
284 default:
285 weight_set(p, -2);
286 break;
290 show_list("bisection 2 initialize", counted, nr, list);
293 * If you have only one parent in the resulting set
294 * then you can reach one commit more than that parent
295 * can reach. So we do not have to run the expensive
296 * count_distance() for single strand of pearls.
298 * However, if you have more than one parents, you cannot
299 * just add their distance and one for yourself, since
300 * they usually reach the same ancestor and you would
301 * end up counting them twice that way.
303 * So we will first count distance of merges the usual
304 * way, and then fill the blanks using cheaper algorithm.
306 for (p = list; p; p = p->next) {
307 if (p->item->object.flags & UNINTERESTING)
308 continue;
309 if (weight(p) != -2)
310 continue;
311 weight_set(p, count_distance(p));
312 clear_distance(list);
314 /* Does it happen to be at exactly half-way? */
315 if (!find_all && halfway(p, nr))
316 return p;
317 counted++;
320 show_list("bisection 2 count_distance", counted, nr, list);
322 while (counted < nr) {
323 for (p = list; p; p = p->next) {
324 struct commit_list *q;
325 unsigned flags = p->item->object.flags;
327 if (0 <= weight(p))
328 continue;
329 for (q = p->item->parents; q; q = q->next) {
330 if (q->item->object.flags & UNINTERESTING)
331 continue;
332 if (0 <= weight(q))
333 break;
335 if (!q)
336 continue;
339 * weight for p is unknown but q is known.
340 * add one for p itself if p is to be counted,
341 * otherwise inherit it from q directly.
343 if (!(flags & TREESAME)) {
344 weight_set(p, weight(q)+1);
345 counted++;
346 show_list("bisection 2 count one",
347 counted, nr, list);
349 else
350 weight_set(p, weight(q));
352 /* Does it happen to be at exactly half-way? */
353 if (!find_all && halfway(p, nr))
354 return p;
358 show_list("bisection 2 counted all", counted, nr, list);
360 if (!find_all)
361 return best_bisection(list, nr);
362 else
363 return best_bisection_sorted(list, nr);
366 void find_bisection(struct commit_list **commit_list, int *reaches,
367 int *all, int find_all)
369 int nr, on_list;
370 struct commit_list *list, *p, *best, *next, *last;
371 int *weights;
373 show_list("bisection 2 entry", 0, 0, *commit_list);
376 * Count the number of total and tree-changing items on the
377 * list, while reversing the list.
379 for (nr = on_list = 0, last = NULL, p = *commit_list;
381 p = next) {
382 unsigned flags = p->item->object.flags;
384 next = p->next;
385 if (flags & UNINTERESTING) {
386 free(p);
387 continue;
389 p->next = last;
390 last = p;
391 if (!(flags & TREESAME))
392 nr++;
393 on_list++;
395 list = last;
396 show_list("bisection 2 sorted", 0, nr, list);
398 *all = nr;
399 weights = xcalloc(on_list, sizeof(*weights));
401 /* Do the real work of finding bisection commit. */
402 best = do_find_bisection(list, nr, weights, find_all);
403 if (best) {
404 if (!find_all) {
405 list->item = best->item;
406 free_commit_list(list->next);
407 best = list;
408 best->next = NULL;
410 *reaches = weight(best);
412 free(weights);
413 *commit_list = best;
416 static int register_ref(const char *refname, const struct object_id *oid,
417 int flags, void *cb_data)
419 struct strbuf good_prefix = STRBUF_INIT;
420 strbuf_addstr(&good_prefix, term_good);
421 strbuf_addstr(&good_prefix, "-");
423 if (!strcmp(refname, term_bad)) {
424 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
425 oidcpy(current_bad_oid, oid);
426 } else if (starts_with(refname, good_prefix.buf)) {
427 oid_array_append(&good_revs, oid);
428 } else if (starts_with(refname, "skip-")) {
429 oid_array_append(&skipped_revs, oid);
432 strbuf_release(&good_prefix);
434 return 0;
437 static int read_bisect_refs(void)
439 return for_each_ref_in("refs/bisect/", register_ref, NULL);
442 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
443 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
444 static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
445 static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
446 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
447 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
448 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
449 static GIT_PATH_FUNC(git_path_head_name, "head-name")
451 static void read_bisect_paths(struct argv_array *array)
453 struct strbuf str = STRBUF_INIT;
454 const char *filename = git_path_bisect_names();
455 FILE *fp = xfopen(filename, "r");
457 while (strbuf_getline_lf(&str, fp) != EOF) {
458 strbuf_trim(&str);
459 if (sq_dequote_to_argv_array(str.buf, array))
460 die(_("Badly quoted content in file '%s': %s"),
461 filename, str.buf);
464 strbuf_release(&str);
465 fclose(fp);
468 static char *join_sha1_array_hex(struct oid_array *array, char delim)
470 struct strbuf joined_hexs = STRBUF_INIT;
471 int i;
473 for (i = 0; i < array->nr; i++) {
474 strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
475 if (i + 1 < array->nr)
476 strbuf_addch(&joined_hexs, delim);
479 return strbuf_detach(&joined_hexs, NULL);
483 * In this function, passing a not NULL skipped_first is very special.
484 * It means that we want to know if the first commit in the list is
485 * skipped because we will want to test a commit away from it if it is
486 * indeed skipped.
487 * So if the first commit is skipped, we cannot take the shortcut to
488 * just "return list" when we find the first non skipped commit, we
489 * have to return a fully filtered list.
491 * We use (*skipped_first == -1) to mean "it has been found that the
492 * first commit is not skipped". In this case *skipped_first is set back
493 * to 0 just before the function returns.
495 struct commit_list *filter_skipped(struct commit_list *list,
496 struct commit_list **tried,
497 int show_all,
498 int *count,
499 int *skipped_first)
501 struct commit_list *filtered = NULL, **f = &filtered;
503 *tried = NULL;
505 if (skipped_first)
506 *skipped_first = 0;
507 if (count)
508 *count = 0;
510 if (!skipped_revs.nr)
511 return list;
513 while (list) {
514 struct commit_list *next = list->next;
515 list->next = NULL;
516 if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
517 if (skipped_first && !*skipped_first)
518 *skipped_first = 1;
519 /* Move current to tried list */
520 *tried = list;
521 tried = &list->next;
522 } else {
523 if (!show_all) {
524 if (!skipped_first || !*skipped_first)
525 return list;
526 } else if (skipped_first && !*skipped_first) {
527 /* This means we know it's not skipped */
528 *skipped_first = -1;
530 /* Move current to filtered list */
531 *f = list;
532 f = &list->next;
533 if (count)
534 (*count)++;
536 list = next;
539 if (skipped_first && *skipped_first == -1)
540 *skipped_first = 0;
542 return filtered;
545 #define PRN_MODULO 32768
548 * This is a pseudo random number generator based on "man 3 rand".
549 * It is not used properly because the seed is the argument and it
550 * is increased by one between each call, but that should not matter
551 * for this application.
553 static unsigned get_prn(unsigned count) {
554 count = count * 1103515245 + 12345;
555 return (count/65536) % PRN_MODULO;
559 * Custom integer square root from
560 * https://en.wikipedia.org/wiki/Integer_square_root
562 static int sqrti(int val)
564 float d, x = val;
566 if (val == 0)
567 return 0;
569 do {
570 float y = (x + (float)val / x) / 2;
571 d = (y > x) ? y - x : x - y;
572 x = y;
573 } while (d >= 0.5);
575 return (int)x;
578 static struct commit_list *skip_away(struct commit_list *list, int count)
580 struct commit_list *cur, *previous;
581 int prn, index, i;
583 prn = get_prn(count);
584 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
586 cur = list;
587 previous = NULL;
589 for (i = 0; cur; cur = cur->next, i++) {
590 if (i == index) {
591 if (oidcmp(&cur->item->object.oid, current_bad_oid))
592 return cur;
593 if (previous)
594 return previous;
595 return list;
597 previous = cur;
600 return list;
603 static struct commit_list *managed_skipped(struct commit_list *list,
604 struct commit_list **tried)
606 int count, skipped_first;
608 *tried = NULL;
610 if (!skipped_revs.nr)
611 return list;
613 list = filter_skipped(list, tried, 0, &count, &skipped_first);
615 if (!skipped_first)
616 return list;
618 return skip_away(list, count);
621 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
622 const char *bad_format, const char *good_format,
623 int read_paths)
625 struct argv_array rev_argv = ARGV_ARRAY_INIT;
626 int i;
628 init_revisions(revs, prefix);
629 revs->abbrev = 0;
630 revs->commit_format = CMIT_FMT_UNSPECIFIED;
632 /* rev_argv.argv[0] will be ignored by setup_revisions */
633 argv_array_push(&rev_argv, "bisect_rev_setup");
634 argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
635 for (i = 0; i < good_revs.nr; i++)
636 argv_array_pushf(&rev_argv, good_format,
637 oid_to_hex(good_revs.oid + i));
638 argv_array_push(&rev_argv, "--");
639 if (read_paths)
640 read_bisect_paths(&rev_argv);
642 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
643 /* XXX leak rev_argv, as "revs" may still be pointing to it */
646 static void bisect_common(struct rev_info *revs)
648 if (prepare_revision_walk(revs))
649 die("revision walk setup failed");
650 if (revs->tree_objects)
651 mark_edges_uninteresting(revs, NULL);
654 static void exit_if_skipped_commits(struct commit_list *tried,
655 const struct object_id *bad)
657 if (!tried)
658 return;
660 printf("There are only 'skip'ped commits left to test.\n"
661 "The first %s commit could be any of:\n", term_bad);
663 for ( ; tried; tried = tried->next)
664 printf("%s\n", oid_to_hex(&tried->item->object.oid));
666 if (bad)
667 printf("%s\n", oid_to_hex(bad));
668 printf(_("We cannot bisect more!\n"));
669 exit(2);
672 static int is_expected_rev(const struct object_id *oid)
674 const char *filename = git_path_bisect_expected_rev();
675 struct stat st;
676 struct strbuf str = STRBUF_INIT;
677 FILE *fp;
678 int res = 0;
680 if (stat(filename, &st) || !S_ISREG(st.st_mode))
681 return 0;
683 fp = fopen_or_warn(filename, "r");
684 if (!fp)
685 return 0;
687 if (strbuf_getline_lf(&str, fp) != EOF)
688 res = !strcmp(str.buf, oid_to_hex(oid));
690 strbuf_release(&str);
691 fclose(fp);
693 return res;
696 static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
698 char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
700 memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
701 update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
703 argv_checkout[2] = bisect_rev_hex;
704 if (no_checkout) {
705 update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
706 UPDATE_REFS_DIE_ON_ERR);
707 } else {
708 int res;
709 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
710 if (res)
711 exit(res);
714 argv_show_branch[1] = bisect_rev_hex;
715 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
718 static struct commit *get_commit_reference(const struct object_id *oid)
720 struct commit *r = lookup_commit_reference(oid);
721 if (!r)
722 die(_("Not a valid commit name %s"), oid_to_hex(oid));
723 return r;
726 static struct commit **get_bad_and_good_commits(int *rev_nr)
728 struct commit **rev;
729 int i, n = 0;
731 ALLOC_ARRAY(rev, 1 + good_revs.nr);
732 rev[n++] = get_commit_reference(current_bad_oid);
733 for (i = 0; i < good_revs.nr; i++)
734 rev[n++] = get_commit_reference(good_revs.oid + i);
735 *rev_nr = n;
737 return rev;
740 static void handle_bad_merge_base(void)
742 if (is_expected_rev(current_bad_oid)) {
743 char *bad_hex = oid_to_hex(current_bad_oid);
744 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
745 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
746 fprintf(stderr, _("The merge base %s is bad.\n"
747 "This means the bug has been fixed "
748 "between %s and [%s].\n"),
749 bad_hex, bad_hex, good_hex);
750 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
751 fprintf(stderr, _("The merge base %s is new.\n"
752 "The property has changed "
753 "between %s and [%s].\n"),
754 bad_hex, bad_hex, good_hex);
755 } else {
756 fprintf(stderr, _("The merge base %s is %s.\n"
757 "This means the first '%s' commit is "
758 "between %s and [%s].\n"),
759 bad_hex, term_bad, term_good, bad_hex, good_hex);
761 exit(3);
764 fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
765 "git bisect cannot work properly in this case.\n"
766 "Maybe you mistook %s and %s revs?\n"),
767 term_good, term_bad, term_good, term_bad);
768 exit(1);
771 static void handle_skipped_merge_base(const struct object_id *mb)
773 char *mb_hex = oid_to_hex(mb);
774 char *bad_hex = oid_to_hex(current_bad_oid);
775 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
777 warning(_("the merge base between %s and [%s] "
778 "must be skipped.\n"
779 "So we cannot be sure the first %s commit is "
780 "between %s and %s.\n"
781 "We continue anyway."),
782 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
783 free(good_hex);
787 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
789 * - If one is "bad" (or "new"), it means the user assumed something wrong
790 * and we must exit with a non 0 error code.
791 * - If one is "good" (or "old"), that's good, we have nothing to do.
792 * - If one is "skipped", we can't know but we should warn.
793 * - If we don't know, we should check it out and ask the user to test.
795 static void check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
797 struct commit_list *result;
799 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
801 for (; result; result = result->next) {
802 const struct object_id *mb = &result->item->object.oid;
803 if (!oidcmp(mb, current_bad_oid)) {
804 handle_bad_merge_base();
805 } else if (0 <= oid_array_lookup(&good_revs, mb)) {
806 continue;
807 } else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
808 handle_skipped_merge_base(mb);
809 } else {
810 printf(_("Bisecting: a merge base must be tested\n"));
811 exit(bisect_checkout(mb, no_checkout));
815 free_commit_list(result);
818 static int check_ancestors(int rev_nr, struct commit **rev, const char *prefix)
820 struct rev_info revs;
821 int res;
823 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
825 bisect_common(&revs);
826 res = (revs.commits != NULL);
828 /* Clean up objects used, as they will be reused. */
829 clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
831 return res;
835 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
836 * ancestor of the "bad" rev.
838 * If that's not the case, we need to check the merge bases.
839 * If a merge base must be tested by the user, its source code will be
840 * checked out to be tested by the user and we will exit.
842 static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
844 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
845 struct stat st;
846 int fd, rev_nr;
847 struct commit **rev;
849 if (!current_bad_oid)
850 die(_("a %s revision is needed"), term_bad);
852 /* Check if file BISECT_ANCESTORS_OK exists. */
853 if (!stat(filename, &st) && S_ISREG(st.st_mode))
854 goto done;
856 /* Bisecting with no good rev is ok. */
857 if (good_revs.nr == 0)
858 goto done;
860 /* Check if all good revs are ancestor of the bad rev. */
861 rev = get_bad_and_good_commits(&rev_nr);
862 if (check_ancestors(rev_nr, rev, prefix))
863 check_merge_bases(rev_nr, rev, no_checkout);
864 free(rev);
866 /* Create file BISECT_ANCESTORS_OK. */
867 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
868 if (fd < 0)
869 warning_errno(_("could not create file '%s'"),
870 filename);
871 else
872 close(fd);
873 done:
874 free(filename);
878 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
880 static void show_diff_tree(const char *prefix, struct commit *commit)
882 struct rev_info opt;
884 /* diff-tree init */
885 init_revisions(&opt, prefix);
886 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
887 opt.abbrev = 0;
888 opt.diff = 1;
890 /* This is what "--pretty" does */
891 opt.verbose_header = 1;
892 opt.use_terminator = 0;
893 opt.commit_format = CMIT_FMT_DEFAULT;
895 /* diff-tree init */
896 if (!opt.diffopt.output_format)
897 opt.diffopt.output_format = DIFF_FORMAT_RAW;
899 setup_revisions(0, NULL, &opt, NULL);
900 log_tree_commit(&opt, commit);
904 * The terms used for this bisect session are stored in BISECT_TERMS.
905 * We read them and store them to adapt the messages accordingly.
906 * Default is bad/good.
908 void read_bisect_terms(const char **read_bad, const char **read_good)
910 struct strbuf str = STRBUF_INIT;
911 const char *filename = git_path_bisect_terms();
912 FILE *fp = fopen(filename, "r");
914 if (!fp) {
915 if (errno == ENOENT) {
916 *read_bad = "bad";
917 *read_good = "good";
918 return;
919 } else {
920 die_errno(_("could not read file '%s'"), filename);
922 } else {
923 strbuf_getline_lf(&str, fp);
924 *read_bad = strbuf_detach(&str, NULL);
925 strbuf_getline_lf(&str, fp);
926 *read_good = strbuf_detach(&str, NULL);
928 strbuf_release(&str);
929 fclose(fp);
933 * We use the convention that exiting with an exit code 10 means that
934 * the bisection process finished successfully.
935 * In this case the calling shell script should exit 0.
937 * If no_checkout is non-zero, the bisection process does not
938 * checkout the trial commit but instead simply updates BISECT_HEAD.
940 int bisect_next_all(const char *prefix, int no_checkout)
942 struct rev_info revs;
943 struct commit_list *tried;
944 int reaches = 0, all = 0, nr, steps;
945 struct object_id *bisect_rev;
946 char *steps_msg;
948 read_bisect_terms(&term_bad, &term_good);
949 if (read_bisect_refs())
950 die(_("reading bisect refs failed"));
952 check_good_are_ancestors_of_bad(prefix, no_checkout);
954 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
955 revs.limited = 1;
957 bisect_common(&revs);
959 find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
960 revs.commits = managed_skipped(revs.commits, &tried);
962 if (!revs.commits) {
964 * We should exit here only if the "bad"
965 * commit is also a "skip" commit.
967 exit_if_skipped_commits(tried, NULL);
969 printf(_("%s was both %s and %s\n"),
970 oid_to_hex(current_bad_oid),
971 term_good,
972 term_bad);
973 exit(1);
976 if (!all) {
977 fprintf(stderr, _("No testable commit found.\n"
978 "Maybe you started with bad path parameters?\n"));
979 exit(4);
982 bisect_rev = &revs.commits->item->object.oid;
984 if (!oidcmp(bisect_rev, current_bad_oid)) {
985 exit_if_skipped_commits(tried, current_bad_oid);
986 printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
987 term_bad);
988 show_diff_tree(prefix, revs.commits->item);
989 /* This means the bisection process succeeded. */
990 exit(10);
993 nr = all - reaches - 1;
994 steps = estimate_bisect_steps(all);
996 steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
997 steps), steps);
999 * TRANSLATORS: the last %s will be replaced with "(roughly %d
1000 * steps)" translation.
1002 printf(Q_("Bisecting: %d revision left to test after this %s\n",
1003 "Bisecting: %d revisions left to test after this %s\n",
1004 nr), nr, steps_msg);
1005 free(steps_msg);
1007 return bisect_checkout(bisect_rev, no_checkout);
1010 static inline int log2i(int n)
1012 int log2 = 0;
1014 for (; n > 1; n >>= 1)
1015 log2++;
1017 return log2;
1020 static inline int exp2i(int n)
1022 return 1 << n;
1026 * Estimate the number of bisect steps left (after the current step)
1028 * For any x between 0 included and 2^n excluded, the probability for
1029 * n - 1 steps left looks like:
1031 * P(2^n + x) == (2^n - x) / (2^n + x)
1033 * and P(2^n + x) < 0.5 means 2^n < 3x
1035 int estimate_bisect_steps(int all)
1037 int n, x, e;
1039 if (all < 3)
1040 return 0;
1042 n = log2i(all);
1043 e = exp2i(n);
1044 x = all - e;
1046 return (e < 3 * x) ? n : n - 1;
1049 static int mark_for_removal(const char *refname, const struct object_id *oid,
1050 int flag, void *cb_data)
1052 struct string_list *refs = cb_data;
1053 char *ref = xstrfmt("refs/bisect%s", refname);
1054 string_list_append(refs, ref);
1055 return 0;
1058 int bisect_clean_state(void)
1060 int result = 0;
1062 /* There may be some refs packed during bisection */
1063 struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
1064 for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
1065 string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
1066 result = delete_refs("bisect: remove", &refs_for_removal, REF_NO_DEREF);
1067 refs_for_removal.strdup_strings = 1;
1068 string_list_clear(&refs_for_removal, 0);
1069 unlink_or_warn(git_path_bisect_expected_rev());
1070 unlink_or_warn(git_path_bisect_ancestors_ok());
1071 unlink_or_warn(git_path_bisect_log());
1072 unlink_or_warn(git_path_bisect_names());
1073 unlink_or_warn(git_path_bisect_run());
1074 unlink_or_warn(git_path_bisect_terms());
1075 /* Cleanup head-name if it got left by an old version of git-bisect */
1076 unlink_or_warn(git_path_head_name());
1078 * Cleanup BISECT_START last to support the --no-checkout option
1079 * introduced in the commit 4796e823a.
1081 unlink_or_warn(git_path_bisect_start());
1083 return result;