git-p4: auto-size the block
[git.git] / bisect.c
bloba579b50884f8e6f8ce8390308d39b2664d050583
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_object_file(&commit->object.oid, &type,
136 &size);
137 const char *subject_start;
138 int subject_len;
140 fprintf(stderr, "%c%c%c ",
141 (flags & TREESAME) ? ' ' : 'T',
142 (flags & UNINTERESTING) ? 'U' : ' ',
143 (flags & COUNTED) ? 'C' : ' ');
144 if (commit->util)
145 fprintf(stderr, "%3d", weight(p));
146 else
147 fprintf(stderr, "---");
148 fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
149 for (pp = commit->parents; pp; pp = pp->next)
150 fprintf(stderr, " %.*s", 8,
151 oid_to_hex(&pp->item->object.oid));
153 subject_len = find_commit_subject(buf, &subject_start);
154 if (subject_len)
155 fprintf(stderr, " %.*s", subject_len, subject_start);
156 fprintf(stderr, "\n");
159 #endif /* DEBUG_BISECT */
161 static struct commit_list *best_bisection(struct commit_list *list, int nr)
163 struct commit_list *p, *best;
164 int best_distance = -1;
166 best = list;
167 for (p = list; p; p = p->next) {
168 int distance;
169 unsigned flags = p->item->object.flags;
171 if (flags & TREESAME)
172 continue;
173 distance = weight(p);
174 if (nr - distance < distance)
175 distance = nr - distance;
176 if (distance > best_distance) {
177 best = p;
178 best_distance = distance;
182 return best;
185 struct commit_dist {
186 struct commit *commit;
187 int distance;
190 static int compare_commit_dist(const void *a_, const void *b_)
192 struct commit_dist *a, *b;
194 a = (struct commit_dist *)a_;
195 b = (struct commit_dist *)b_;
196 if (a->distance != b->distance)
197 return b->distance - a->distance; /* desc sort */
198 return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
201 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
203 struct commit_list *p;
204 struct commit_dist *array = xcalloc(nr, sizeof(*array));
205 struct strbuf buf = STRBUF_INIT;
206 int cnt, i;
208 for (p = list, cnt = 0; p; p = p->next) {
209 int distance;
210 unsigned flags = p->item->object.flags;
212 if (flags & TREESAME)
213 continue;
214 distance = weight(p);
215 if (nr - distance < distance)
216 distance = nr - distance;
217 array[cnt].commit = p->item;
218 array[cnt].distance = distance;
219 cnt++;
221 QSORT(array, cnt, compare_commit_dist);
222 for (p = list, i = 0; i < cnt; i++) {
223 struct object *obj = &(array[i].commit->object);
225 strbuf_reset(&buf);
226 strbuf_addf(&buf, "dist=%d", array[i].distance);
227 add_name_decoration(DECORATION_NONE, buf.buf, obj);
229 p->item = array[i].commit;
230 if (i < cnt - 1)
231 p = p->next;
233 if (p) {
234 free_commit_list(p->next);
235 p->next = NULL;
237 strbuf_release(&buf);
238 free(array);
239 return list;
243 * zero or positive weight is the number of interesting commits it can
244 * reach, including itself. Especially, weight = 0 means it does not
245 * reach any tree-changing commits (e.g. just above uninteresting one
246 * but traversal is with pathspec).
248 * weight = -1 means it has one parent and its distance is yet to
249 * be computed.
251 * weight = -2 means it has more than one parent and its distance is
252 * unknown. After running count_distance() first, they will get zero
253 * or positive distance.
255 static struct commit_list *do_find_bisection(struct commit_list *list,
256 int nr, int *weights,
257 int find_all)
259 int n, counted;
260 struct commit_list *p;
262 counted = 0;
264 for (n = 0, p = list; p; p = p->next) {
265 struct commit *commit = p->item;
266 unsigned flags = commit->object.flags;
268 p->item->util = &weights[n++];
269 switch (count_interesting_parents(commit)) {
270 case 0:
271 if (!(flags & TREESAME)) {
272 weight_set(p, 1);
273 counted++;
274 show_list("bisection 2 count one",
275 counted, nr, list);
278 * otherwise, it is known not to reach any
279 * tree-changing commit and gets weight 0.
281 break;
282 case 1:
283 weight_set(p, -1);
284 break;
285 default:
286 weight_set(p, -2);
287 break;
291 show_list("bisection 2 initialize", counted, nr, list);
294 * If you have only one parent in the resulting set
295 * then you can reach one commit more than that parent
296 * can reach. So we do not have to run the expensive
297 * count_distance() for single strand of pearls.
299 * However, if you have more than one parents, you cannot
300 * just add their distance and one for yourself, since
301 * they usually reach the same ancestor and you would
302 * end up counting them twice that way.
304 * So we will first count distance of merges the usual
305 * way, and then fill the blanks using cheaper algorithm.
307 for (p = list; p; p = p->next) {
308 if (p->item->object.flags & UNINTERESTING)
309 continue;
310 if (weight(p) != -2)
311 continue;
312 weight_set(p, count_distance(p));
313 clear_distance(list);
315 /* Does it happen to be at exactly half-way? */
316 if (!find_all && halfway(p, nr))
317 return p;
318 counted++;
321 show_list("bisection 2 count_distance", counted, nr, list);
323 while (counted < nr) {
324 for (p = list; p; p = p->next) {
325 struct commit_list *q;
326 unsigned flags = p->item->object.flags;
328 if (0 <= weight(p))
329 continue;
330 for (q = p->item->parents; q; q = q->next) {
331 if (q->item->object.flags & UNINTERESTING)
332 continue;
333 if (0 <= weight(q))
334 break;
336 if (!q)
337 continue;
340 * weight for p is unknown but q is known.
341 * add one for p itself if p is to be counted,
342 * otherwise inherit it from q directly.
344 if (!(flags & TREESAME)) {
345 weight_set(p, weight(q)+1);
346 counted++;
347 show_list("bisection 2 count one",
348 counted, nr, list);
350 else
351 weight_set(p, weight(q));
353 /* Does it happen to be at exactly half-way? */
354 if (!find_all && halfway(p, nr))
355 return p;
359 show_list("bisection 2 counted all", counted, nr, list);
361 if (!find_all)
362 return best_bisection(list, nr);
363 else
364 return best_bisection_sorted(list, nr);
367 void find_bisection(struct commit_list **commit_list, int *reaches,
368 int *all, int find_all)
370 int nr, on_list;
371 struct commit_list *list, *p, *best, *next, *last;
372 int *weights;
374 show_list("bisection 2 entry", 0, 0, *commit_list);
377 * Count the number of total and tree-changing items on the
378 * list, while reversing the list.
380 for (nr = on_list = 0, last = NULL, p = *commit_list;
382 p = next) {
383 unsigned flags = p->item->object.flags;
385 next = p->next;
386 if (flags & UNINTERESTING) {
387 free(p);
388 continue;
390 p->next = last;
391 last = p;
392 if (!(flags & TREESAME))
393 nr++;
394 on_list++;
396 list = last;
397 show_list("bisection 2 sorted", 0, nr, list);
399 *all = nr;
400 weights = xcalloc(on_list, sizeof(*weights));
402 /* Do the real work of finding bisection commit. */
403 best = do_find_bisection(list, nr, weights, find_all);
404 if (best) {
405 if (!find_all) {
406 list->item = best->item;
407 free_commit_list(list->next);
408 best = list;
409 best->next = NULL;
411 *reaches = weight(best);
413 free(weights);
414 *commit_list = best;
417 static int register_ref(const char *refname, const struct object_id *oid,
418 int flags, void *cb_data)
420 struct strbuf good_prefix = STRBUF_INIT;
421 strbuf_addstr(&good_prefix, term_good);
422 strbuf_addstr(&good_prefix, "-");
424 if (!strcmp(refname, term_bad)) {
425 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
426 oidcpy(current_bad_oid, oid);
427 } else if (starts_with(refname, good_prefix.buf)) {
428 oid_array_append(&good_revs, oid);
429 } else if (starts_with(refname, "skip-")) {
430 oid_array_append(&skipped_revs, oid);
433 strbuf_release(&good_prefix);
435 return 0;
438 static int read_bisect_refs(void)
440 return for_each_ref_in("refs/bisect/", register_ref, NULL);
443 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
444 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
445 static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
446 static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
447 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
448 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
449 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
450 static GIT_PATH_FUNC(git_path_head_name, "head-name")
452 static void read_bisect_paths(struct argv_array *array)
454 struct strbuf str = STRBUF_INIT;
455 const char *filename = git_path_bisect_names();
456 FILE *fp = xfopen(filename, "r");
458 while (strbuf_getline_lf(&str, fp) != EOF) {
459 strbuf_trim(&str);
460 if (sq_dequote_to_argv_array(str.buf, array))
461 die(_("Badly quoted content in file '%s': %s"),
462 filename, str.buf);
465 strbuf_release(&str);
466 fclose(fp);
469 static char *join_sha1_array_hex(struct oid_array *array, char delim)
471 struct strbuf joined_hexs = STRBUF_INIT;
472 int i;
474 for (i = 0; i < array->nr; i++) {
475 strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
476 if (i + 1 < array->nr)
477 strbuf_addch(&joined_hexs, delim);
480 return strbuf_detach(&joined_hexs, NULL);
484 * In this function, passing a not NULL skipped_first is very special.
485 * It means that we want to know if the first commit in the list is
486 * skipped because we will want to test a commit away from it if it is
487 * indeed skipped.
488 * So if the first commit is skipped, we cannot take the shortcut to
489 * just "return list" when we find the first non skipped commit, we
490 * have to return a fully filtered list.
492 * We use (*skipped_first == -1) to mean "it has been found that the
493 * first commit is not skipped". In this case *skipped_first is set back
494 * to 0 just before the function returns.
496 struct commit_list *filter_skipped(struct commit_list *list,
497 struct commit_list **tried,
498 int show_all,
499 int *count,
500 int *skipped_first)
502 struct commit_list *filtered = NULL, **f = &filtered;
504 *tried = NULL;
506 if (skipped_first)
507 *skipped_first = 0;
508 if (count)
509 *count = 0;
511 if (!skipped_revs.nr)
512 return list;
514 while (list) {
515 struct commit_list *next = list->next;
516 list->next = NULL;
517 if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
518 if (skipped_first && !*skipped_first)
519 *skipped_first = 1;
520 /* Move current to tried list */
521 *tried = list;
522 tried = &list->next;
523 } else {
524 if (!show_all) {
525 if (!skipped_first || !*skipped_first)
526 return list;
527 } else if (skipped_first && !*skipped_first) {
528 /* This means we know it's not skipped */
529 *skipped_first = -1;
531 /* Move current to filtered list */
532 *f = list;
533 f = &list->next;
534 if (count)
535 (*count)++;
537 list = next;
540 if (skipped_first && *skipped_first == -1)
541 *skipped_first = 0;
543 return filtered;
546 #define PRN_MODULO 32768
549 * This is a pseudo random number generator based on "man 3 rand".
550 * It is not used properly because the seed is the argument and it
551 * is increased by one between each call, but that should not matter
552 * for this application.
554 static unsigned get_prn(unsigned count) {
555 count = count * 1103515245 + 12345;
556 return (count/65536) % PRN_MODULO;
560 * Custom integer square root from
561 * https://en.wikipedia.org/wiki/Integer_square_root
563 static int sqrti(int val)
565 float d, x = val;
567 if (val == 0)
568 return 0;
570 do {
571 float y = (x + (float)val / x) / 2;
572 d = (y > x) ? y - x : x - y;
573 x = y;
574 } while (d >= 0.5);
576 return (int)x;
579 static struct commit_list *skip_away(struct commit_list *list, int count)
581 struct commit_list *cur, *previous;
582 int prn, index, i;
584 prn = get_prn(count);
585 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
587 cur = list;
588 previous = NULL;
590 for (i = 0; cur; cur = cur->next, i++) {
591 if (i == index) {
592 if (oidcmp(&cur->item->object.oid, current_bad_oid))
593 return cur;
594 if (previous)
595 return previous;
596 return list;
598 previous = cur;
601 return list;
604 static struct commit_list *managed_skipped(struct commit_list *list,
605 struct commit_list **tried)
607 int count, skipped_first;
609 *tried = NULL;
611 if (!skipped_revs.nr)
612 return list;
614 list = filter_skipped(list, tried, 0, &count, &skipped_first);
616 if (!skipped_first)
617 return list;
619 return skip_away(list, count);
622 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
623 const char *bad_format, const char *good_format,
624 int read_paths)
626 struct argv_array rev_argv = ARGV_ARRAY_INIT;
627 int i;
629 init_revisions(revs, prefix);
630 revs->abbrev = 0;
631 revs->commit_format = CMIT_FMT_UNSPECIFIED;
633 /* rev_argv.argv[0] will be ignored by setup_revisions */
634 argv_array_push(&rev_argv, "bisect_rev_setup");
635 argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
636 for (i = 0; i < good_revs.nr; i++)
637 argv_array_pushf(&rev_argv, good_format,
638 oid_to_hex(good_revs.oid + i));
639 argv_array_push(&rev_argv, "--");
640 if (read_paths)
641 read_bisect_paths(&rev_argv);
643 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
644 /* XXX leak rev_argv, as "revs" may still be pointing to it */
647 static void bisect_common(struct rev_info *revs)
649 if (prepare_revision_walk(revs))
650 die("revision walk setup failed");
651 if (revs->tree_objects)
652 mark_edges_uninteresting(revs, NULL);
655 static void exit_if_skipped_commits(struct commit_list *tried,
656 const struct object_id *bad)
658 if (!tried)
659 return;
661 printf("There are only 'skip'ped commits left to test.\n"
662 "The first %s commit could be any of:\n", term_bad);
664 for ( ; tried; tried = tried->next)
665 printf("%s\n", oid_to_hex(&tried->item->object.oid));
667 if (bad)
668 printf("%s\n", oid_to_hex(bad));
669 printf(_("We cannot bisect more!\n"));
670 exit(2);
673 static int is_expected_rev(const struct object_id *oid)
675 const char *filename = git_path_bisect_expected_rev();
676 struct stat st;
677 struct strbuf str = STRBUF_INIT;
678 FILE *fp;
679 int res = 0;
681 if (stat(filename, &st) || !S_ISREG(st.st_mode))
682 return 0;
684 fp = fopen_or_warn(filename, "r");
685 if (!fp)
686 return 0;
688 if (strbuf_getline_lf(&str, fp) != EOF)
689 res = !strcmp(str.buf, oid_to_hex(oid));
691 strbuf_release(&str);
692 fclose(fp);
694 return res;
697 static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
699 char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
701 memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
702 update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
704 argv_checkout[2] = bisect_rev_hex;
705 if (no_checkout) {
706 update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
707 UPDATE_REFS_DIE_ON_ERR);
708 } else {
709 int res;
710 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
711 if (res)
712 exit(res);
715 argv_show_branch[1] = bisect_rev_hex;
716 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
719 static struct commit *get_commit_reference(const struct object_id *oid)
721 struct commit *r = lookup_commit_reference(oid);
722 if (!r)
723 die(_("Not a valid commit name %s"), oid_to_hex(oid));
724 return r;
727 static struct commit **get_bad_and_good_commits(int *rev_nr)
729 struct commit **rev;
730 int i, n = 0;
732 ALLOC_ARRAY(rev, 1 + good_revs.nr);
733 rev[n++] = get_commit_reference(current_bad_oid);
734 for (i = 0; i < good_revs.nr; i++)
735 rev[n++] = get_commit_reference(good_revs.oid + i);
736 *rev_nr = n;
738 return rev;
741 static void handle_bad_merge_base(void)
743 if (is_expected_rev(current_bad_oid)) {
744 char *bad_hex = oid_to_hex(current_bad_oid);
745 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
746 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
747 fprintf(stderr, _("The merge base %s is bad.\n"
748 "This means the bug has been fixed "
749 "between %s and [%s].\n"),
750 bad_hex, bad_hex, good_hex);
751 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
752 fprintf(stderr, _("The merge base %s is new.\n"
753 "The property has changed "
754 "between %s and [%s].\n"),
755 bad_hex, bad_hex, good_hex);
756 } else {
757 fprintf(stderr, _("The merge base %s is %s.\n"
758 "This means the first '%s' commit is "
759 "between %s and [%s].\n"),
760 bad_hex, term_bad, term_good, bad_hex, good_hex);
762 exit(3);
765 fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
766 "git bisect cannot work properly in this case.\n"
767 "Maybe you mistook %s and %s revs?\n"),
768 term_good, term_bad, term_good, term_bad);
769 exit(1);
772 static void handle_skipped_merge_base(const struct object_id *mb)
774 char *mb_hex = oid_to_hex(mb);
775 char *bad_hex = oid_to_hex(current_bad_oid);
776 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
778 warning(_("the merge base between %s and [%s] "
779 "must be skipped.\n"
780 "So we cannot be sure the first %s commit is "
781 "between %s and %s.\n"
782 "We continue anyway."),
783 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
784 free(good_hex);
788 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
790 * - If one is "bad" (or "new"), it means the user assumed something wrong
791 * and we must exit with a non 0 error code.
792 * - If one is "good" (or "old"), that's good, we have nothing to do.
793 * - If one is "skipped", we can't know but we should warn.
794 * - If we don't know, we should check it out and ask the user to test.
796 static void check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
798 struct commit_list *result;
800 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
802 for (; result; result = result->next) {
803 const struct object_id *mb = &result->item->object.oid;
804 if (!oidcmp(mb, current_bad_oid)) {
805 handle_bad_merge_base();
806 } else if (0 <= oid_array_lookup(&good_revs, mb)) {
807 continue;
808 } else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
809 handle_skipped_merge_base(mb);
810 } else {
811 printf(_("Bisecting: a merge base must be tested\n"));
812 exit(bisect_checkout(mb, no_checkout));
816 free_commit_list(result);
819 static int check_ancestors(int rev_nr, struct commit **rev, const char *prefix)
821 struct rev_info revs;
822 int res;
824 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
826 bisect_common(&revs);
827 res = (revs.commits != NULL);
829 /* Clean up objects used, as they will be reused. */
830 clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
832 return res;
836 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
837 * ancestor of the "bad" rev.
839 * If that's not the case, we need to check the merge bases.
840 * If a merge base must be tested by the user, its source code will be
841 * checked out to be tested by the user and we will exit.
843 static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
845 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
846 struct stat st;
847 int fd, rev_nr;
848 struct commit **rev;
850 if (!current_bad_oid)
851 die(_("a %s revision is needed"), term_bad);
853 /* Check if file BISECT_ANCESTORS_OK exists. */
854 if (!stat(filename, &st) && S_ISREG(st.st_mode))
855 goto done;
857 /* Bisecting with no good rev is ok. */
858 if (good_revs.nr == 0)
859 goto done;
861 /* Check if all good revs are ancestor of the bad rev. */
862 rev = get_bad_and_good_commits(&rev_nr);
863 if (check_ancestors(rev_nr, rev, prefix))
864 check_merge_bases(rev_nr, rev, no_checkout);
865 free(rev);
867 /* Create file BISECT_ANCESTORS_OK. */
868 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
869 if (fd < 0)
870 warning_errno(_("could not create file '%s'"),
871 filename);
872 else
873 close(fd);
874 done:
875 free(filename);
879 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
881 static void show_diff_tree(const char *prefix, struct commit *commit)
883 struct rev_info opt;
885 /* diff-tree init */
886 init_revisions(&opt, prefix);
887 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
888 opt.abbrev = 0;
889 opt.diff = 1;
891 /* This is what "--pretty" does */
892 opt.verbose_header = 1;
893 opt.use_terminator = 0;
894 opt.commit_format = CMIT_FMT_DEFAULT;
896 /* diff-tree init */
897 if (!opt.diffopt.output_format)
898 opt.diffopt.output_format = DIFF_FORMAT_RAW;
900 setup_revisions(0, NULL, &opt, NULL);
901 log_tree_commit(&opt, commit);
905 * The terms used for this bisect session are stored in BISECT_TERMS.
906 * We read them and store them to adapt the messages accordingly.
907 * Default is bad/good.
909 void read_bisect_terms(const char **read_bad, const char **read_good)
911 struct strbuf str = STRBUF_INIT;
912 const char *filename = git_path_bisect_terms();
913 FILE *fp = fopen(filename, "r");
915 if (!fp) {
916 if (errno == ENOENT) {
917 *read_bad = "bad";
918 *read_good = "good";
919 return;
920 } else {
921 die_errno(_("could not read file '%s'"), filename);
923 } else {
924 strbuf_getline_lf(&str, fp);
925 *read_bad = strbuf_detach(&str, NULL);
926 strbuf_getline_lf(&str, fp);
927 *read_good = strbuf_detach(&str, NULL);
929 strbuf_release(&str);
930 fclose(fp);
934 * We use the convention that exiting with an exit code 10 means that
935 * the bisection process finished successfully.
936 * In this case the calling shell script should exit 0.
938 * If no_checkout is non-zero, the bisection process does not
939 * checkout the trial commit but instead simply updates BISECT_HEAD.
941 int bisect_next_all(const char *prefix, int no_checkout)
943 struct rev_info revs;
944 struct commit_list *tried;
945 int reaches = 0, all = 0, nr, steps;
946 struct object_id *bisect_rev;
947 char *steps_msg;
949 read_bisect_terms(&term_bad, &term_good);
950 if (read_bisect_refs())
951 die(_("reading bisect refs failed"));
953 check_good_are_ancestors_of_bad(prefix, no_checkout);
955 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
956 revs.limited = 1;
958 bisect_common(&revs);
960 find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
961 revs.commits = managed_skipped(revs.commits, &tried);
963 if (!revs.commits) {
965 * We should exit here only if the "bad"
966 * commit is also a "skip" commit.
968 exit_if_skipped_commits(tried, NULL);
970 printf(_("%s was both %s and %s\n"),
971 oid_to_hex(current_bad_oid),
972 term_good,
973 term_bad);
974 exit(1);
977 if (!all) {
978 fprintf(stderr, _("No testable commit found.\n"
979 "Maybe you started with bad path parameters?\n"));
980 exit(4);
983 bisect_rev = &revs.commits->item->object.oid;
985 if (!oidcmp(bisect_rev, current_bad_oid)) {
986 exit_if_skipped_commits(tried, current_bad_oid);
987 printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
988 term_bad);
989 show_diff_tree(prefix, revs.commits->item);
990 /* This means the bisection process succeeded. */
991 exit(10);
994 nr = all - reaches - 1;
995 steps = estimate_bisect_steps(all);
997 steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
998 steps), steps);
1000 * TRANSLATORS: the last %s will be replaced with "(roughly %d
1001 * steps)" translation.
1003 printf(Q_("Bisecting: %d revision left to test after this %s\n",
1004 "Bisecting: %d revisions left to test after this %s\n",
1005 nr), nr, steps_msg);
1006 free(steps_msg);
1008 return bisect_checkout(bisect_rev, no_checkout);
1011 static inline int log2i(int n)
1013 int log2 = 0;
1015 for (; n > 1; n >>= 1)
1016 log2++;
1018 return log2;
1021 static inline int exp2i(int n)
1023 return 1 << n;
1027 * Estimate the number of bisect steps left (after the current step)
1029 * For any x between 0 included and 2^n excluded, the probability for
1030 * n - 1 steps left looks like:
1032 * P(2^n + x) == (2^n - x) / (2^n + x)
1034 * and P(2^n + x) < 0.5 means 2^n < 3x
1036 int estimate_bisect_steps(int all)
1038 int n, x, e;
1040 if (all < 3)
1041 return 0;
1043 n = log2i(all);
1044 e = exp2i(n);
1045 x = all - e;
1047 return (e < 3 * x) ? n : n - 1;
1050 static int mark_for_removal(const char *refname, const struct object_id *oid,
1051 int flag, void *cb_data)
1053 struct string_list *refs = cb_data;
1054 char *ref = xstrfmt("refs/bisect%s", refname);
1055 string_list_append(refs, ref);
1056 return 0;
1059 int bisect_clean_state(void)
1061 int result = 0;
1063 /* There may be some refs packed during bisection */
1064 struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
1065 for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
1066 string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
1067 result = delete_refs("bisect: remove", &refs_for_removal, REF_NO_DEREF);
1068 refs_for_removal.strdup_strings = 1;
1069 string_list_clear(&refs_for_removal, 0);
1070 unlink_or_warn(git_path_bisect_expected_rev());
1071 unlink_or_warn(git_path_bisect_ancestors_ok());
1072 unlink_or_warn(git_path_bisect_log());
1073 unlink_or_warn(git_path_bisect_names());
1074 unlink_or_warn(git_path_bisect_run());
1075 unlink_or_warn(git_path_bisect_terms());
1076 /* Cleanup head-name if it got left by an old version of git-bisect */
1077 unlink_or_warn(git_path_head_name());
1079 * Cleanup BISECT_START last to support the --no-checkout option
1080 * introduced in the commit 4796e823a.
1082 unlink_or_warn(git_path_bisect_start());
1084 return result;