Merge branch 'rb/hpe'
[git.git] / bisect.c
blob6bf521138a590496a7b3fa7c2515ac53f815a1e3
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"
15 #include "commit-slab.h"
16 #include "commit-reach.h"
17 #include "object-store.h"
19 static struct oid_array good_revs;
20 static struct oid_array skipped_revs;
22 static struct object_id *current_bad_oid;
24 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
25 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
27 static const char *term_bad;
28 static const char *term_good;
30 /* Remember to update object flag allocation in object.h */
31 #define COUNTED (1u<<16)
34 * This is a truly stupid algorithm, but it's only
35 * used for bisection, and we just don't care enough.
37 * We care just barely enough to avoid recursing for
38 * non-merge entries.
40 static int count_distance(struct commit_list *entry)
42 int nr = 0;
44 while (entry) {
45 struct commit *commit = entry->item;
46 struct commit_list *p;
48 if (commit->object.flags & (UNINTERESTING | COUNTED))
49 break;
50 if (!(commit->object.flags & TREESAME))
51 nr++;
52 commit->object.flags |= COUNTED;
53 p = commit->parents;
54 entry = p;
55 if (p) {
56 p = p->next;
57 while (p) {
58 nr += count_distance(p);
59 p = p->next;
64 return nr;
67 static void clear_distance(struct commit_list *list)
69 while (list) {
70 struct commit *commit = list->item;
71 commit->object.flags &= ~COUNTED;
72 list = list->next;
76 define_commit_slab(commit_weight, int *);
77 static struct commit_weight commit_weight;
79 #define DEBUG_BISECT 0
81 static inline int weight(struct commit_list *elem)
83 return **commit_weight_at(&commit_weight, elem->item);
86 static inline void weight_set(struct commit_list *elem, int weight)
88 **commit_weight_at(&commit_weight, elem->item) = weight;
91 static int count_interesting_parents(struct commit *commit)
93 struct commit_list *p;
94 int count;
96 for (count = 0, p = commit->parents; p; p = p->next) {
97 if (p->item->object.flags & UNINTERESTING)
98 continue;
99 count++;
101 return count;
104 static inline int halfway(struct commit_list *p, int nr)
107 * Don't short-cut something we are not going to return!
109 if (p->item->object.flags & TREESAME)
110 return 0;
111 if (DEBUG_BISECT)
112 return 0;
114 * 2 and 3 are halfway of 5.
115 * 3 is halfway of 6 but 2 and 4 are not.
117 switch (2 * weight(p) - nr) {
118 case -1: case 0: case 1:
119 return 1;
120 default:
121 return 0;
125 static void show_list(const char *debug, int counted, int nr,
126 struct commit_list *list)
128 struct commit_list *p;
130 if (!DEBUG_BISECT)
131 return;
133 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
135 for (p = list; p; p = p->next) {
136 struct commit_list *pp;
137 struct commit *commit = p->item;
138 unsigned flags = commit->object.flags;
139 enum object_type type;
140 unsigned long size;
141 char *buf = read_object_file(&commit->object.oid, &type,
142 &size);
143 const char *subject_start;
144 int subject_len;
146 fprintf(stderr, "%c%c%c ",
147 (flags & TREESAME) ? ' ' : 'T',
148 (flags & UNINTERESTING) ? 'U' : ' ',
149 (flags & COUNTED) ? 'C' : ' ');
150 if (*commit_weight_at(&commit_weight, p->item))
151 fprintf(stderr, "%3d", weight(p));
152 else
153 fprintf(stderr, "---");
154 fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
155 for (pp = commit->parents; pp; pp = pp->next)
156 fprintf(stderr, " %.*s", 8,
157 oid_to_hex(&pp->item->object.oid));
159 subject_len = find_commit_subject(buf, &subject_start);
160 if (subject_len)
161 fprintf(stderr, " %.*s", subject_len, subject_start);
162 fprintf(stderr, "\n");
166 static struct commit_list *best_bisection(struct commit_list *list, int nr)
168 struct commit_list *p, *best;
169 int best_distance = -1;
171 best = list;
172 for (p = list; p; p = p->next) {
173 int distance;
174 unsigned flags = p->item->object.flags;
176 if (flags & TREESAME)
177 continue;
178 distance = weight(p);
179 if (nr - distance < distance)
180 distance = nr - distance;
181 if (distance > best_distance) {
182 best = p;
183 best_distance = distance;
187 return best;
190 struct commit_dist {
191 struct commit *commit;
192 int distance;
195 static int compare_commit_dist(const void *a_, const void *b_)
197 struct commit_dist *a, *b;
199 a = (struct commit_dist *)a_;
200 b = (struct commit_dist *)b_;
201 if (a->distance != b->distance)
202 return b->distance - a->distance; /* desc sort */
203 return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
206 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
208 struct commit_list *p;
209 struct commit_dist *array = xcalloc(nr, sizeof(*array));
210 struct strbuf buf = STRBUF_INIT;
211 int cnt, i;
213 for (p = list, cnt = 0; p; p = p->next) {
214 int distance;
215 unsigned flags = p->item->object.flags;
217 if (flags & TREESAME)
218 continue;
219 distance = weight(p);
220 if (nr - distance < distance)
221 distance = nr - distance;
222 array[cnt].commit = p->item;
223 array[cnt].distance = distance;
224 cnt++;
226 QSORT(array, cnt, compare_commit_dist);
227 for (p = list, i = 0; i < cnt; i++) {
228 struct object *obj = &(array[i].commit->object);
230 strbuf_reset(&buf);
231 strbuf_addf(&buf, "dist=%d", array[i].distance);
232 add_name_decoration(DECORATION_NONE, buf.buf, obj);
234 p->item = array[i].commit;
235 if (i < cnt - 1)
236 p = p->next;
238 if (p) {
239 free_commit_list(p->next);
240 p->next = NULL;
242 strbuf_release(&buf);
243 free(array);
244 return list;
248 * zero or positive weight is the number of interesting commits it can
249 * reach, including itself. Especially, weight = 0 means it does not
250 * reach any tree-changing commits (e.g. just above uninteresting one
251 * but traversal is with pathspec).
253 * weight = -1 means it has one parent and its distance is yet to
254 * be computed.
256 * weight = -2 means it has more than one parent and its distance is
257 * unknown. After running count_distance() first, they will get zero
258 * or positive distance.
260 static struct commit_list *do_find_bisection(struct commit_list *list,
261 int nr, int *weights,
262 int find_all)
264 int n, counted;
265 struct commit_list *p;
267 counted = 0;
269 for (n = 0, p = list; p; p = p->next) {
270 struct commit *commit = p->item;
271 unsigned flags = commit->object.flags;
273 *commit_weight_at(&commit_weight, p->item) = &weights[n++];
274 switch (count_interesting_parents(commit)) {
275 case 0:
276 if (!(flags & TREESAME)) {
277 weight_set(p, 1);
278 counted++;
279 show_list("bisection 2 count one",
280 counted, nr, list);
283 * otherwise, it is known not to reach any
284 * tree-changing commit and gets weight 0.
286 break;
287 case 1:
288 weight_set(p, -1);
289 break;
290 default:
291 weight_set(p, -2);
292 break;
296 show_list("bisection 2 initialize", counted, nr, list);
299 * If you have only one parent in the resulting set
300 * then you can reach one commit more than that parent
301 * can reach. So we do not have to run the expensive
302 * count_distance() for single strand of pearls.
304 * However, if you have more than one parents, you cannot
305 * just add their distance and one for yourself, since
306 * they usually reach the same ancestor and you would
307 * end up counting them twice that way.
309 * So we will first count distance of merges the usual
310 * way, and then fill the blanks using cheaper algorithm.
312 for (p = list; p; p = p->next) {
313 if (p->item->object.flags & UNINTERESTING)
314 continue;
315 if (weight(p) != -2)
316 continue;
317 weight_set(p, count_distance(p));
318 clear_distance(list);
320 /* Does it happen to be at exactly half-way? */
321 if (!find_all && halfway(p, nr))
322 return p;
323 counted++;
326 show_list("bisection 2 count_distance", counted, nr, list);
328 while (counted < nr) {
329 for (p = list; p; p = p->next) {
330 struct commit_list *q;
331 unsigned flags = p->item->object.flags;
333 if (0 <= weight(p))
334 continue;
335 for (q = p->item->parents; q; q = q->next) {
336 if (q->item->object.flags & UNINTERESTING)
337 continue;
338 if (0 <= weight(q))
339 break;
341 if (!q)
342 continue;
345 * weight for p is unknown but q is known.
346 * add one for p itself if p is to be counted,
347 * otherwise inherit it from q directly.
349 if (!(flags & TREESAME)) {
350 weight_set(p, weight(q)+1);
351 counted++;
352 show_list("bisection 2 count one",
353 counted, nr, list);
355 else
356 weight_set(p, weight(q));
358 /* Does it happen to be at exactly half-way? */
359 if (!find_all && halfway(p, nr))
360 return p;
364 show_list("bisection 2 counted all", counted, nr, list);
366 if (!find_all)
367 return best_bisection(list, nr);
368 else
369 return best_bisection_sorted(list, nr);
372 void find_bisection(struct commit_list **commit_list, int *reaches,
373 int *all, int find_all)
375 int nr, on_list;
376 struct commit_list *list, *p, *best, *next, *last;
377 int *weights;
379 show_list("bisection 2 entry", 0, 0, *commit_list);
380 init_commit_weight(&commit_weight);
383 * Count the number of total and tree-changing items on the
384 * list, while reversing the list.
386 for (nr = on_list = 0, last = NULL, p = *commit_list;
388 p = next) {
389 unsigned flags = p->item->object.flags;
391 next = p->next;
392 if (flags & UNINTERESTING) {
393 free(p);
394 continue;
396 p->next = last;
397 last = p;
398 if (!(flags & TREESAME))
399 nr++;
400 on_list++;
402 list = last;
403 show_list("bisection 2 sorted", 0, nr, list);
405 *all = nr;
406 weights = xcalloc(on_list, sizeof(*weights));
408 /* Do the real work of finding bisection commit. */
409 best = do_find_bisection(list, nr, weights, find_all);
410 if (best) {
411 if (!find_all) {
412 list->item = best->item;
413 free_commit_list(list->next);
414 best = list;
415 best->next = NULL;
417 *reaches = weight(best);
419 free(weights);
420 *commit_list = best;
421 clear_commit_weight(&commit_weight);
424 static int register_ref(const char *refname, const struct object_id *oid,
425 int flags, void *cb_data)
427 struct strbuf good_prefix = STRBUF_INIT;
428 strbuf_addstr(&good_prefix, term_good);
429 strbuf_addstr(&good_prefix, "-");
431 if (!strcmp(refname, term_bad)) {
432 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
433 oidcpy(current_bad_oid, oid);
434 } else if (starts_with(refname, good_prefix.buf)) {
435 oid_array_append(&good_revs, oid);
436 } else if (starts_with(refname, "skip-")) {
437 oid_array_append(&skipped_revs, oid);
440 strbuf_release(&good_prefix);
442 return 0;
445 static int read_bisect_refs(void)
447 return for_each_ref_in("refs/bisect/", register_ref, NULL);
450 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
451 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
452 static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
453 static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
454 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
455 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
456 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
457 static GIT_PATH_FUNC(git_path_head_name, "head-name")
459 static void read_bisect_paths(struct argv_array *array)
461 struct strbuf str = STRBUF_INIT;
462 const char *filename = git_path_bisect_names();
463 FILE *fp = xfopen(filename, "r");
465 while (strbuf_getline_lf(&str, fp) != EOF) {
466 strbuf_trim(&str);
467 if (sq_dequote_to_argv_array(str.buf, array))
468 die(_("Badly quoted content in file '%s': %s"),
469 filename, str.buf);
472 strbuf_release(&str);
473 fclose(fp);
476 static char *join_sha1_array_hex(struct oid_array *array, char delim)
478 struct strbuf joined_hexs = STRBUF_INIT;
479 int i;
481 for (i = 0; i < array->nr; i++) {
482 strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
483 if (i + 1 < array->nr)
484 strbuf_addch(&joined_hexs, delim);
487 return strbuf_detach(&joined_hexs, NULL);
491 * In this function, passing a not NULL skipped_first is very special.
492 * It means that we want to know if the first commit in the list is
493 * skipped because we will want to test a commit away from it if it is
494 * indeed skipped.
495 * So if the first commit is skipped, we cannot take the shortcut to
496 * just "return list" when we find the first non skipped commit, we
497 * have to return a fully filtered list.
499 * We use (*skipped_first == -1) to mean "it has been found that the
500 * first commit is not skipped". In this case *skipped_first is set back
501 * to 0 just before the function returns.
503 struct commit_list *filter_skipped(struct commit_list *list,
504 struct commit_list **tried,
505 int show_all,
506 int *count,
507 int *skipped_first)
509 struct commit_list *filtered = NULL, **f = &filtered;
511 *tried = NULL;
513 if (skipped_first)
514 *skipped_first = 0;
515 if (count)
516 *count = 0;
518 if (!skipped_revs.nr)
519 return list;
521 while (list) {
522 struct commit_list *next = list->next;
523 list->next = NULL;
524 if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
525 if (skipped_first && !*skipped_first)
526 *skipped_first = 1;
527 /* Move current to tried list */
528 *tried = list;
529 tried = &list->next;
530 } else {
531 if (!show_all) {
532 if (!skipped_first || !*skipped_first)
533 return list;
534 } else if (skipped_first && !*skipped_first) {
535 /* This means we know it's not skipped */
536 *skipped_first = -1;
538 /* Move current to filtered list */
539 *f = list;
540 f = &list->next;
541 if (count)
542 (*count)++;
544 list = next;
547 if (skipped_first && *skipped_first == -1)
548 *skipped_first = 0;
550 return filtered;
553 #define PRN_MODULO 32768
556 * This is a pseudo random number generator based on "man 3 rand".
557 * It is not used properly because the seed is the argument and it
558 * is increased by one between each call, but that should not matter
559 * for this application.
561 static unsigned get_prn(unsigned count)
563 count = count * 1103515245 + 12345;
564 return (count/65536) % PRN_MODULO;
568 * Custom integer square root from
569 * https://en.wikipedia.org/wiki/Integer_square_root
571 static int sqrti(int val)
573 float d, x = val;
575 if (val == 0)
576 return 0;
578 do {
579 float y = (x + (float)val / x) / 2;
580 d = (y > x) ? y - x : x - y;
581 x = y;
582 } while (d >= 0.5);
584 return (int)x;
587 static struct commit_list *skip_away(struct commit_list *list, int count)
589 struct commit_list *cur, *previous;
590 int prn, index, i;
592 prn = get_prn(count);
593 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
595 cur = list;
596 previous = NULL;
598 for (i = 0; cur; cur = cur->next, i++) {
599 if (i == index) {
600 if (!oideq(&cur->item->object.oid, current_bad_oid))
601 return cur;
602 if (previous)
603 return previous;
604 return list;
606 previous = cur;
609 return list;
612 static struct commit_list *managed_skipped(struct commit_list *list,
613 struct commit_list **tried)
615 int count, skipped_first;
617 *tried = NULL;
619 if (!skipped_revs.nr)
620 return list;
622 list = filter_skipped(list, tried, 0, &count, &skipped_first);
624 if (!skipped_first)
625 return list;
627 return skip_away(list, count);
630 static void bisect_rev_setup(struct repository *r, struct rev_info *revs,
631 const char *prefix,
632 const char *bad_format, const char *good_format,
633 int read_paths)
635 struct argv_array rev_argv = ARGV_ARRAY_INIT;
636 int i;
638 repo_init_revisions(r, revs, prefix);
639 revs->abbrev = 0;
640 revs->commit_format = CMIT_FMT_UNSPECIFIED;
642 /* rev_argv.argv[0] will be ignored by setup_revisions */
643 argv_array_push(&rev_argv, "bisect_rev_setup");
644 argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
645 for (i = 0; i < good_revs.nr; i++)
646 argv_array_pushf(&rev_argv, good_format,
647 oid_to_hex(good_revs.oid + i));
648 argv_array_push(&rev_argv, "--");
649 if (read_paths)
650 read_bisect_paths(&rev_argv);
652 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
653 /* XXX leak rev_argv, as "revs" may still be pointing to it */
656 static void bisect_common(struct rev_info *revs)
658 if (prepare_revision_walk(revs))
659 die("revision walk setup failed");
660 if (revs->tree_objects)
661 mark_edges_uninteresting(revs, NULL);
664 static void exit_if_skipped_commits(struct commit_list *tried,
665 const struct object_id *bad)
667 if (!tried)
668 return;
670 printf("There are only 'skip'ped commits left to test.\n"
671 "The first %s commit could be any of:\n", term_bad);
673 for ( ; tried; tried = tried->next)
674 printf("%s\n", oid_to_hex(&tried->item->object.oid));
676 if (bad)
677 printf("%s\n", oid_to_hex(bad));
678 printf(_("We cannot bisect more!\n"));
679 exit(2);
682 static int is_expected_rev(const struct object_id *oid)
684 const char *filename = git_path_bisect_expected_rev();
685 struct stat st;
686 struct strbuf str = STRBUF_INIT;
687 FILE *fp;
688 int res = 0;
690 if (stat(filename, &st) || !S_ISREG(st.st_mode))
691 return 0;
693 fp = fopen_or_warn(filename, "r");
694 if (!fp)
695 return 0;
697 if (strbuf_getline_lf(&str, fp) != EOF)
698 res = !strcmp(str.buf, oid_to_hex(oid));
700 strbuf_release(&str);
701 fclose(fp);
703 return res;
706 static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
708 char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
710 memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
711 update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
713 argv_checkout[2] = bisect_rev_hex;
714 if (no_checkout) {
715 update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
716 UPDATE_REFS_DIE_ON_ERR);
717 } else {
718 int res;
719 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
720 if (res)
721 exit(res);
724 argv_show_branch[1] = bisect_rev_hex;
725 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
728 static struct commit *get_commit_reference(struct repository *r,
729 const struct object_id *oid)
731 struct commit *c = lookup_commit_reference(r, oid);
732 if (!c)
733 die(_("Not a valid commit name %s"), oid_to_hex(oid));
734 return c;
737 static struct commit **get_bad_and_good_commits(struct repository *r,
738 int *rev_nr)
740 struct commit **rev;
741 int i, n = 0;
743 ALLOC_ARRAY(rev, 1 + good_revs.nr);
744 rev[n++] = get_commit_reference(r, current_bad_oid);
745 for (i = 0; i < good_revs.nr; i++)
746 rev[n++] = get_commit_reference(r, good_revs.oid + i);
747 *rev_nr = n;
749 return rev;
752 static void handle_bad_merge_base(void)
754 if (is_expected_rev(current_bad_oid)) {
755 char *bad_hex = oid_to_hex(current_bad_oid);
756 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
757 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
758 fprintf(stderr, _("The merge base %s is bad.\n"
759 "This means the bug has been fixed "
760 "between %s and [%s].\n"),
761 bad_hex, bad_hex, good_hex);
762 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
763 fprintf(stderr, _("The merge base %s is new.\n"
764 "The property has changed "
765 "between %s and [%s].\n"),
766 bad_hex, bad_hex, good_hex);
767 } else {
768 fprintf(stderr, _("The merge base %s is %s.\n"
769 "This means the first '%s' commit is "
770 "between %s and [%s].\n"),
771 bad_hex, term_bad, term_good, bad_hex, good_hex);
773 exit(3);
776 fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
777 "git bisect cannot work properly in this case.\n"
778 "Maybe you mistook %s and %s revs?\n"),
779 term_good, term_bad, term_good, term_bad);
780 exit(1);
783 static void handle_skipped_merge_base(const struct object_id *mb)
785 char *mb_hex = oid_to_hex(mb);
786 char *bad_hex = oid_to_hex(current_bad_oid);
787 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
789 warning(_("the merge base between %s and [%s] "
790 "must be skipped.\n"
791 "So we cannot be sure the first %s commit is "
792 "between %s and %s.\n"
793 "We continue anyway."),
794 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
795 free(good_hex);
799 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
801 * - If one is "bad" (or "new"), it means the user assumed something wrong
802 * and we must exit with a non 0 error code.
803 * - If one is "good" (or "old"), that's good, we have nothing to do.
804 * - If one is "skipped", we can't know but we should warn.
805 * - If we don't know, we should check it out and ask the user to test.
807 static void check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
809 struct commit_list *result;
811 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
813 for (; result; result = result->next) {
814 const struct object_id *mb = &result->item->object.oid;
815 if (oideq(mb, current_bad_oid)) {
816 handle_bad_merge_base();
817 } else if (0 <= oid_array_lookup(&good_revs, mb)) {
818 continue;
819 } else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
820 handle_skipped_merge_base(mb);
821 } else {
822 printf(_("Bisecting: a merge base must be tested\n"));
823 exit(bisect_checkout(mb, no_checkout));
827 free_commit_list(result);
830 static int check_ancestors(struct repository *r, int rev_nr,
831 struct commit **rev, const char *prefix)
833 struct rev_info revs;
834 int res;
836 bisect_rev_setup(r, &revs, prefix, "^%s", "%s", 0);
838 bisect_common(&revs);
839 res = (revs.commits != NULL);
841 /* Clean up objects used, as they will be reused. */
842 clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
844 return res;
848 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
849 * ancestor of the "bad" rev.
851 * If that's not the case, we need to check the merge bases.
852 * If a merge base must be tested by the user, its source code will be
853 * checked out to be tested by the user and we will exit.
855 static void check_good_are_ancestors_of_bad(struct repository *r,
856 const char *prefix,
857 int no_checkout)
859 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
860 struct stat st;
861 int fd, rev_nr;
862 struct commit **rev;
864 if (!current_bad_oid)
865 die(_("a %s revision is needed"), term_bad);
867 /* Check if file BISECT_ANCESTORS_OK exists. */
868 if (!stat(filename, &st) && S_ISREG(st.st_mode))
869 goto done;
871 /* Bisecting with no good rev is ok. */
872 if (good_revs.nr == 0)
873 goto done;
875 /* Check if all good revs are ancestor of the bad rev. */
876 rev = get_bad_and_good_commits(r, &rev_nr);
877 if (check_ancestors(r, rev_nr, rev, prefix))
878 check_merge_bases(rev_nr, rev, no_checkout);
879 free(rev);
881 /* Create file BISECT_ANCESTORS_OK. */
882 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
883 if (fd < 0)
884 warning_errno(_("could not create file '%s'"),
885 filename);
886 else
887 close(fd);
888 done:
889 free(filename);
893 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
895 static void show_diff_tree(struct repository *r,
896 const char *prefix,
897 struct commit *commit)
899 struct rev_info opt;
901 /* diff-tree init */
902 repo_init_revisions(r, &opt, prefix);
903 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
904 opt.abbrev = 0;
905 opt.diff = 1;
907 /* This is what "--pretty" does */
908 opt.verbose_header = 1;
909 opt.use_terminator = 0;
910 opt.commit_format = CMIT_FMT_DEFAULT;
912 /* diff-tree init */
913 if (!opt.diffopt.output_format)
914 opt.diffopt.output_format = DIFF_FORMAT_RAW;
916 setup_revisions(0, NULL, &opt, NULL);
917 log_tree_commit(&opt, commit);
921 * The terms used for this bisect session are stored in BISECT_TERMS.
922 * We read them and store them to adapt the messages accordingly.
923 * Default is bad/good.
925 void read_bisect_terms(const char **read_bad, const char **read_good)
927 struct strbuf str = STRBUF_INIT;
928 const char *filename = git_path_bisect_terms();
929 FILE *fp = fopen(filename, "r");
931 if (!fp) {
932 if (errno == ENOENT) {
933 *read_bad = "bad";
934 *read_good = "good";
935 return;
936 } else {
937 die_errno(_("could not read file '%s'"), filename);
939 } else {
940 strbuf_getline_lf(&str, fp);
941 *read_bad = strbuf_detach(&str, NULL);
942 strbuf_getline_lf(&str, fp);
943 *read_good = strbuf_detach(&str, NULL);
945 strbuf_release(&str);
946 fclose(fp);
950 * We use the convention that exiting with an exit code 10 means that
951 * the bisection process finished successfully.
952 * In this case the calling shell script should exit 0.
954 * If no_checkout is non-zero, the bisection process does not
955 * checkout the trial commit but instead simply updates BISECT_HEAD.
957 int bisect_next_all(struct repository *r, const char *prefix, int no_checkout)
959 struct rev_info revs;
960 struct commit_list *tried;
961 int reaches = 0, all = 0, nr, steps;
962 struct object_id *bisect_rev;
963 char *steps_msg;
965 read_bisect_terms(&term_bad, &term_good);
966 if (read_bisect_refs())
967 die(_("reading bisect refs failed"));
969 check_good_are_ancestors_of_bad(r, prefix, no_checkout);
971 bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
972 revs.limited = 1;
974 bisect_common(&revs);
976 find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
977 revs.commits = managed_skipped(revs.commits, &tried);
979 if (!revs.commits) {
981 * We should exit here only if the "bad"
982 * commit is also a "skip" commit.
984 exit_if_skipped_commits(tried, NULL);
986 printf(_("%s was both %s and %s\n"),
987 oid_to_hex(current_bad_oid),
988 term_good,
989 term_bad);
990 exit(1);
993 if (!all) {
994 fprintf(stderr, _("No testable commit found.\n"
995 "Maybe you started with bad path parameters?\n"));
996 exit(4);
999 bisect_rev = &revs.commits->item->object.oid;
1001 if (oideq(bisect_rev, current_bad_oid)) {
1002 exit_if_skipped_commits(tried, current_bad_oid);
1003 printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
1004 term_bad);
1005 show_diff_tree(r, prefix, revs.commits->item);
1006 /* This means the bisection process succeeded. */
1007 exit(10);
1010 nr = all - reaches - 1;
1011 steps = estimate_bisect_steps(all);
1013 steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
1014 steps), steps);
1016 * TRANSLATORS: the last %s will be replaced with "(roughly %d
1017 * steps)" translation.
1019 printf(Q_("Bisecting: %d revision left to test after this %s\n",
1020 "Bisecting: %d revisions left to test after this %s\n",
1021 nr), nr, steps_msg);
1022 free(steps_msg);
1024 return bisect_checkout(bisect_rev, no_checkout);
1027 static inline int log2i(int n)
1029 int log2 = 0;
1031 for (; n > 1; n >>= 1)
1032 log2++;
1034 return log2;
1037 static inline int exp2i(int n)
1039 return 1 << n;
1043 * Estimate the number of bisect steps left (after the current step)
1045 * For any x between 0 included and 2^n excluded, the probability for
1046 * n - 1 steps left looks like:
1048 * P(2^n + x) == (2^n - x) / (2^n + x)
1050 * and P(2^n + x) < 0.5 means 2^n < 3x
1052 int estimate_bisect_steps(int all)
1054 int n, x, e;
1056 if (all < 3)
1057 return 0;
1059 n = log2i(all);
1060 e = exp2i(n);
1061 x = all - e;
1063 return (e < 3 * x) ? n : n - 1;
1066 static int mark_for_removal(const char *refname, const struct object_id *oid,
1067 int flag, void *cb_data)
1069 struct string_list *refs = cb_data;
1070 char *ref = xstrfmt("refs/bisect%s", refname);
1071 string_list_append(refs, ref);
1072 return 0;
1075 int bisect_clean_state(void)
1077 int result = 0;
1079 /* There may be some refs packed during bisection */
1080 struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
1081 for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
1082 string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
1083 result = delete_refs("bisect: remove", &refs_for_removal, REF_NO_DEREF);
1084 refs_for_removal.strdup_strings = 1;
1085 string_list_clear(&refs_for_removal, 0);
1086 unlink_or_warn(git_path_bisect_expected_rev());
1087 unlink_or_warn(git_path_bisect_ancestors_ok());
1088 unlink_or_warn(git_path_bisect_log());
1089 unlink_or_warn(git_path_bisect_names());
1090 unlink_or_warn(git_path_bisect_run());
1091 unlink_or_warn(git_path_bisect_terms());
1092 /* Cleanup head-name if it got left by an old version of git-bisect */
1093 unlink_or_warn(git_path_head_name());
1095 * Cleanup BISECT_START last to support the --no-checkout option
1096 * introduced in the commit 4796e823a.
1098 unlink_or_warn(git_path_bisect_start());
1100 return result;