git-multimail: update to release 1.2.0
[git.git] / bisect.c
blob053d1a2ab91a6c41a0fe957569ff905d12b00bee
1 #include "cache.h"
2 #include "commit.h"
3 #include "diff.h"
4 #include "revision.h"
5 #include "refs.h"
6 #include "list-objects.h"
7 #include "quote.h"
8 #include "sha1-lookup.h"
9 #include "run-command.h"
10 #include "log-tree.h"
11 #include "bisect.h"
12 #include "sha1-array.h"
13 #include "argv-array.h"
15 static struct sha1_array good_revs;
16 static struct sha1_array skipped_revs;
18 static struct object_id *current_bad_oid;
20 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
21 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
23 static const char *term_bad;
24 static const char *term_good;
26 /* Remember to update object flag allocation in object.h */
27 #define COUNTED (1u<<16)
30 * This is a truly stupid algorithm, but it's only
31 * used for bisection, and we just don't care enough.
33 * We care just barely enough to avoid recursing for
34 * non-merge entries.
36 static int count_distance(struct commit_list *entry)
38 int nr = 0;
40 while (entry) {
41 struct commit *commit = entry->item;
42 struct commit_list *p;
44 if (commit->object.flags & (UNINTERESTING | COUNTED))
45 break;
46 if (!(commit->object.flags & TREESAME))
47 nr++;
48 commit->object.flags |= COUNTED;
49 p = commit->parents;
50 entry = p;
51 if (p) {
52 p = p->next;
53 while (p) {
54 nr += count_distance(p);
55 p = p->next;
60 return nr;
63 static void clear_distance(struct commit_list *list)
65 while (list) {
66 struct commit *commit = list->item;
67 commit->object.flags &= ~COUNTED;
68 list = list->next;
72 #define DEBUG_BISECT 0
74 static inline int weight(struct commit_list *elem)
76 return *((int*)(elem->item->util));
79 static inline void weight_set(struct commit_list *elem, int weight)
81 *((int*)(elem->item->util)) = weight;
84 static int count_interesting_parents(struct commit *commit)
86 struct commit_list *p;
87 int count;
89 for (count = 0, p = commit->parents; p; p = p->next) {
90 if (p->item->object.flags & UNINTERESTING)
91 continue;
92 count++;
94 return count;
97 static inline int halfway(struct commit_list *p, int nr)
100 * Don't short-cut something we are not going to return!
102 if (p->item->object.flags & TREESAME)
103 return 0;
104 if (DEBUG_BISECT)
105 return 0;
107 * 2 and 3 are halfway of 5.
108 * 3 is halfway of 6 but 2 and 4 are not.
110 switch (2 * weight(p) - nr) {
111 case -1: case 0: case 1:
112 return 1;
113 default:
114 return 0;
118 #if !DEBUG_BISECT
119 #define show_list(a,b,c,d) do { ; } while (0)
120 #else
121 static void show_list(const char *debug, int counted, int nr,
122 struct commit_list *list)
124 struct commit_list *p;
126 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
128 for (p = list; p; p = p->next) {
129 struct commit_list *pp;
130 struct commit *commit = p->item;
131 unsigned flags = commit->object.flags;
132 enum object_type type;
133 unsigned long size;
134 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
135 const char *subject_start;
136 int subject_len;
138 fprintf(stderr, "%c%c%c ",
139 (flags & TREESAME) ? ' ' : 'T',
140 (flags & UNINTERESTING) ? 'U' : ' ',
141 (flags & COUNTED) ? 'C' : ' ');
142 if (commit->util)
143 fprintf(stderr, "%3d", weight(p));
144 else
145 fprintf(stderr, "---");
146 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
147 for (pp = commit->parents; pp; pp = pp->next)
148 fprintf(stderr, " %.*s", 8,
149 sha1_to_hex(pp->item->object.sha1));
151 subject_len = find_commit_subject(buf, &subject_start);
152 if (subject_len)
153 fprintf(stderr, " %.*s", subject_len, subject_start);
154 fprintf(stderr, "\n");
157 #endif /* DEBUG_BISECT */
159 static struct commit_list *best_bisection(struct commit_list *list, int nr)
161 struct commit_list *p, *best;
162 int best_distance = -1;
164 best = list;
165 for (p = list; p; p = p->next) {
166 int distance;
167 unsigned flags = p->item->object.flags;
169 if (flags & TREESAME)
170 continue;
171 distance = weight(p);
172 if (nr - distance < distance)
173 distance = nr - distance;
174 if (distance > best_distance) {
175 best = p;
176 best_distance = distance;
180 return best;
183 struct commit_dist {
184 struct commit *commit;
185 int distance;
188 static int compare_commit_dist(const void *a_, const void *b_)
190 struct commit_dist *a, *b;
192 a = (struct commit_dist *)a_;
193 b = (struct commit_dist *)b_;
194 if (a->distance != b->distance)
195 return b->distance - a->distance; /* desc sort */
196 return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
199 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
201 struct commit_list *p;
202 struct commit_dist *array = xcalloc(nr, sizeof(*array));
203 int cnt, i;
205 for (p = list, cnt = 0; p; p = p->next) {
206 int distance;
207 unsigned flags = p->item->object.flags;
209 if (flags & TREESAME)
210 continue;
211 distance = weight(p);
212 if (nr - distance < distance)
213 distance = nr - distance;
214 array[cnt].commit = p->item;
215 array[cnt].distance = distance;
216 cnt++;
218 qsort(array, cnt, sizeof(*array), compare_commit_dist);
219 for (p = list, i = 0; i < cnt; i++) {
220 char buf[100]; /* enough for dist=%d */
221 struct object *obj = &(array[i].commit->object);
223 snprintf(buf, sizeof(buf), "dist=%d", array[i].distance);
224 add_name_decoration(DECORATION_NONE, buf, obj);
226 p->item = array[i].commit;
227 p = p->next;
229 if (p)
230 p->next = NULL;
231 free(array);
232 return list;
236 * zero or positive weight is the number of interesting commits it can
237 * reach, including itself. Especially, weight = 0 means it does not
238 * reach any tree-changing commits (e.g. just above uninteresting one
239 * but traversal is with pathspec).
241 * weight = -1 means it has one parent and its distance is yet to
242 * be computed.
244 * weight = -2 means it has more than one parent and its distance is
245 * unknown. After running count_distance() first, they will get zero
246 * or positive distance.
248 static struct commit_list *do_find_bisection(struct commit_list *list,
249 int nr, int *weights,
250 int find_all)
252 int n, counted;
253 struct commit_list *p;
255 counted = 0;
257 for (n = 0, p = list; p; p = p->next) {
258 struct commit *commit = p->item;
259 unsigned flags = commit->object.flags;
261 p->item->util = &weights[n++];
262 switch (count_interesting_parents(commit)) {
263 case 0:
264 if (!(flags & TREESAME)) {
265 weight_set(p, 1);
266 counted++;
267 show_list("bisection 2 count one",
268 counted, nr, list);
271 * otherwise, it is known not to reach any
272 * tree-changing commit and gets weight 0.
274 break;
275 case 1:
276 weight_set(p, -1);
277 break;
278 default:
279 weight_set(p, -2);
280 break;
284 show_list("bisection 2 initialize", counted, nr, list);
287 * If you have only one parent in the resulting set
288 * then you can reach one commit more than that parent
289 * can reach. So we do not have to run the expensive
290 * count_distance() for single strand of pearls.
292 * However, if you have more than one parents, you cannot
293 * just add their distance and one for yourself, since
294 * they usually reach the same ancestor and you would
295 * end up counting them twice that way.
297 * So we will first count distance of merges the usual
298 * way, and then fill the blanks using cheaper algorithm.
300 for (p = list; p; p = p->next) {
301 if (p->item->object.flags & UNINTERESTING)
302 continue;
303 if (weight(p) != -2)
304 continue;
305 weight_set(p, count_distance(p));
306 clear_distance(list);
308 /* Does it happen to be at exactly half-way? */
309 if (!find_all && halfway(p, nr))
310 return p;
311 counted++;
314 show_list("bisection 2 count_distance", counted, nr, list);
316 while (counted < nr) {
317 for (p = list; p; p = p->next) {
318 struct commit_list *q;
319 unsigned flags = p->item->object.flags;
321 if (0 <= weight(p))
322 continue;
323 for (q = p->item->parents; q; q = q->next) {
324 if (q->item->object.flags & UNINTERESTING)
325 continue;
326 if (0 <= weight(q))
327 break;
329 if (!q)
330 continue;
333 * weight for p is unknown but q is known.
334 * add one for p itself if p is to be counted,
335 * otherwise inherit it from q directly.
337 if (!(flags & TREESAME)) {
338 weight_set(p, weight(q)+1);
339 counted++;
340 show_list("bisection 2 count one",
341 counted, nr, list);
343 else
344 weight_set(p, weight(q));
346 /* Does it happen to be at exactly half-way? */
347 if (!find_all && halfway(p, nr))
348 return p;
352 show_list("bisection 2 counted all", counted, nr, list);
354 if (!find_all)
355 return best_bisection(list, nr);
356 else
357 return best_bisection_sorted(list, nr);
360 struct commit_list *find_bisection(struct commit_list *list,
361 int *reaches, int *all,
362 int find_all)
364 int nr, on_list;
365 struct commit_list *p, *best, *next, *last;
366 int *weights;
368 show_list("bisection 2 entry", 0, 0, list);
371 * Count the number of total and tree-changing items on the
372 * list, while reversing the list.
374 for (nr = on_list = 0, last = NULL, p = list;
376 p = next) {
377 unsigned flags = p->item->object.flags;
379 next = p->next;
380 if (flags & UNINTERESTING)
381 continue;
382 p->next = last;
383 last = p;
384 if (!(flags & TREESAME))
385 nr++;
386 on_list++;
388 list = last;
389 show_list("bisection 2 sorted", 0, nr, list);
391 *all = nr;
392 weights = xcalloc(on_list, sizeof(*weights));
394 /* Do the real work of finding bisection commit. */
395 best = do_find_bisection(list, nr, weights, find_all);
396 if (best) {
397 if (!find_all)
398 best->next = NULL;
399 *reaches = weight(best);
401 free(weights);
402 return best;
405 static int register_ref(const char *refname, const struct object_id *oid,
406 int flags, void *cb_data)
408 struct strbuf good_prefix = STRBUF_INIT;
409 strbuf_addstr(&good_prefix, term_good);
410 strbuf_addstr(&good_prefix, "-");
412 if (!strcmp(refname, term_bad)) {
413 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
414 oidcpy(current_bad_oid, oid);
415 } else if (starts_with(refname, good_prefix.buf)) {
416 sha1_array_append(&good_revs, oid->hash);
417 } else if (starts_with(refname, "skip-")) {
418 sha1_array_append(&skipped_revs, oid->hash);
421 strbuf_release(&good_prefix);
423 return 0;
426 static int read_bisect_refs(void)
428 return for_each_ref_in("refs/bisect/", register_ref, NULL);
431 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
432 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
434 static void read_bisect_paths(struct argv_array *array)
436 struct strbuf str = STRBUF_INIT;
437 const char *filename = git_path_bisect_names();
438 FILE *fp = fopen(filename, "r");
440 if (!fp)
441 die_errno("Could not open file '%s'", filename);
443 while (strbuf_getline(&str, fp, '\n') != EOF) {
444 strbuf_trim(&str);
445 if (sq_dequote_to_argv_array(str.buf, array))
446 die("Badly quoted content in file '%s': %s",
447 filename, str.buf);
450 strbuf_release(&str);
451 fclose(fp);
454 static char *join_sha1_array_hex(struct sha1_array *array, char delim)
456 struct strbuf joined_hexs = STRBUF_INIT;
457 int i;
459 for (i = 0; i < array->nr; i++) {
460 strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
461 if (i + 1 < array->nr)
462 strbuf_addch(&joined_hexs, delim);
465 return strbuf_detach(&joined_hexs, NULL);
469 * In this function, passing a not NULL skipped_first is very special.
470 * It means that we want to know if the first commit in the list is
471 * skipped because we will want to test a commit away from it if it is
472 * indeed skipped.
473 * So if the first commit is skipped, we cannot take the shortcut to
474 * just "return list" when we find the first non skipped commit, we
475 * have to return a fully filtered list.
477 * We use (*skipped_first == -1) to mean "it has been found that the
478 * first commit is not skipped". In this case *skipped_first is set back
479 * to 0 just before the function returns.
481 struct commit_list *filter_skipped(struct commit_list *list,
482 struct commit_list **tried,
483 int show_all,
484 int *count,
485 int *skipped_first)
487 struct commit_list *filtered = NULL, **f = &filtered;
489 *tried = NULL;
491 if (skipped_first)
492 *skipped_first = 0;
493 if (count)
494 *count = 0;
496 if (!skipped_revs.nr)
497 return list;
499 while (list) {
500 struct commit_list *next = list->next;
501 list->next = NULL;
502 if (0 <= sha1_array_lookup(&skipped_revs,
503 list->item->object.sha1)) {
504 if (skipped_first && !*skipped_first)
505 *skipped_first = 1;
506 /* Move current to tried list */
507 *tried = list;
508 tried = &list->next;
509 } else {
510 if (!show_all) {
511 if (!skipped_first || !*skipped_first)
512 return list;
513 } else if (skipped_first && !*skipped_first) {
514 /* This means we know it's not skipped */
515 *skipped_first = -1;
517 /* Move current to filtered list */
518 *f = list;
519 f = &list->next;
520 if (count)
521 (*count)++;
523 list = next;
526 if (skipped_first && *skipped_first == -1)
527 *skipped_first = 0;
529 return filtered;
532 #define PRN_MODULO 32768
535 * This is a pseudo random number generator based on "man 3 rand".
536 * It is not used properly because the seed is the argument and it
537 * is increased by one between each call, but that should not matter
538 * for this application.
540 static unsigned get_prn(unsigned count) {
541 count = count * 1103515245 + 12345;
542 return (count/65536) % PRN_MODULO;
546 * Custom integer square root from
547 * http://en.wikipedia.org/wiki/Integer_square_root
549 static int sqrti(int val)
551 float d, x = val;
553 if (val == 0)
554 return 0;
556 do {
557 float y = (x + (float)val / x) / 2;
558 d = (y > x) ? y - x : x - y;
559 x = y;
560 } while (d >= 0.5);
562 return (int)x;
565 static struct commit_list *skip_away(struct commit_list *list, int count)
567 struct commit_list *cur, *previous;
568 int prn, index, i;
570 prn = get_prn(count);
571 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
573 cur = list;
574 previous = NULL;
576 for (i = 0; cur; cur = cur->next, i++) {
577 if (i == index) {
578 if (hashcmp(cur->item->object.sha1, current_bad_oid->hash))
579 return cur;
580 if (previous)
581 return previous;
582 return list;
584 previous = cur;
587 return list;
590 static struct commit_list *managed_skipped(struct commit_list *list,
591 struct commit_list **tried)
593 int count, skipped_first;
595 *tried = NULL;
597 if (!skipped_revs.nr)
598 return list;
600 list = filter_skipped(list, tried, 0, &count, &skipped_first);
602 if (!skipped_first)
603 return list;
605 return skip_away(list, count);
608 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
609 const char *bad_format, const char *good_format,
610 int read_paths)
612 struct argv_array rev_argv = ARGV_ARRAY_INIT;
613 int i;
615 init_revisions(revs, prefix);
616 revs->abbrev = 0;
617 revs->commit_format = CMIT_FMT_UNSPECIFIED;
619 /* rev_argv.argv[0] will be ignored by setup_revisions */
620 argv_array_push(&rev_argv, "bisect_rev_setup");
621 argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
622 for (i = 0; i < good_revs.nr; i++)
623 argv_array_pushf(&rev_argv, good_format,
624 sha1_to_hex(good_revs.sha1[i]));
625 argv_array_push(&rev_argv, "--");
626 if (read_paths)
627 read_bisect_paths(&rev_argv);
629 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
630 /* XXX leak rev_argv, as "revs" may still be pointing to it */
633 static void bisect_common(struct rev_info *revs)
635 if (prepare_revision_walk(revs))
636 die("revision walk setup failed");
637 if (revs->tree_objects)
638 mark_edges_uninteresting(revs, NULL);
641 static void exit_if_skipped_commits(struct commit_list *tried,
642 const struct object_id *bad)
644 if (!tried)
645 return;
647 printf("There are only 'skip'ped commits left to test.\n"
648 "The first %s commit could be any of:\n", term_bad);
649 print_commit_list(tried, "%s\n", "%s\n");
650 if (bad)
651 printf("%s\n", oid_to_hex(bad));
652 printf("We cannot bisect more!\n");
653 exit(2);
656 static int is_expected_rev(const struct object_id *oid)
658 const char *filename = git_path_bisect_expected_rev();
659 struct stat st;
660 struct strbuf str = STRBUF_INIT;
661 FILE *fp;
662 int res = 0;
664 if (stat(filename, &st) || !S_ISREG(st.st_mode))
665 return 0;
667 fp = fopen(filename, "r");
668 if (!fp)
669 return 0;
671 if (strbuf_getline(&str, fp, '\n') != EOF)
672 res = !strcmp(str.buf, oid_to_hex(oid));
674 strbuf_release(&str);
675 fclose(fp);
677 return res;
680 static int bisect_checkout(const unsigned char *bisect_rev, int no_checkout)
682 char bisect_rev_hex[GIT_SHA1_HEXSZ + 1];
684 memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
685 update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
687 argv_checkout[2] = bisect_rev_hex;
688 if (no_checkout) {
689 update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
690 } else {
691 int res;
692 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
693 if (res)
694 exit(res);
697 argv_show_branch[1] = bisect_rev_hex;
698 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
701 static struct commit *get_commit_reference(const unsigned char *sha1)
703 struct commit *r = lookup_commit_reference(sha1);
704 if (!r)
705 die("Not a valid commit name %s", sha1_to_hex(sha1));
706 return r;
709 static struct commit **get_bad_and_good_commits(int *rev_nr)
711 int len = 1 + good_revs.nr;
712 struct commit **rev = xmalloc(len * sizeof(*rev));
713 int i, n = 0;
715 rev[n++] = get_commit_reference(current_bad_oid->hash);
716 for (i = 0; i < good_revs.nr; i++)
717 rev[n++] = get_commit_reference(good_revs.sha1[i]);
718 *rev_nr = n;
720 return rev;
723 static void handle_bad_merge_base(void)
725 if (is_expected_rev(current_bad_oid)) {
726 char *bad_hex = oid_to_hex(current_bad_oid);
727 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
728 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
729 fprintf(stderr, "The merge base %s is bad.\n"
730 "This means the bug has been fixed "
731 "between %s and [%s].\n",
732 bad_hex, bad_hex, good_hex);
733 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
734 fprintf(stderr, "The merge base %s is new.\n"
735 "The property has changed "
736 "between %s and [%s].\n",
737 bad_hex, bad_hex, good_hex);
738 } else {
739 fprintf(stderr, "The merge base %s is %s.\n"
740 "This means the first '%s' commit is "
741 "between %s and [%s].\n",
742 bad_hex, term_bad, term_good, bad_hex, good_hex);
744 exit(3);
747 fprintf(stderr, "Some %s revs are not ancestor of the %s rev.\n"
748 "git bisect cannot work properly in this case.\n"
749 "Maybe you mistook %s and %s revs?\n",
750 term_good, term_bad, term_good, term_bad);
751 exit(1);
754 static void handle_skipped_merge_base(const unsigned char *mb)
756 char *mb_hex = sha1_to_hex(mb);
757 char *bad_hex = sha1_to_hex(current_bad_oid->hash);
758 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
760 warning("the merge base between %s and [%s] "
761 "must be skipped.\n"
762 "So we cannot be sure the first %s commit is "
763 "between %s and %s.\n"
764 "We continue anyway.",
765 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
766 free(good_hex);
770 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
772 * - If one is "bad" (or "new"), it means the user assumed something wrong
773 * and we must exit with a non 0 error code.
774 * - If one is "good" (or "old"), that's good, we have nothing to do.
775 * - If one is "skipped", we can't know but we should warn.
776 * - If we don't know, we should check it out and ask the user to test.
778 static void check_merge_bases(int no_checkout)
780 struct commit_list *result;
781 int rev_nr;
782 struct commit **rev = get_bad_and_good_commits(&rev_nr);
784 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
786 for (; result; result = result->next) {
787 const unsigned char *mb = result->item->object.sha1;
788 if (!hashcmp(mb, current_bad_oid->hash)) {
789 handle_bad_merge_base();
790 } else if (0 <= sha1_array_lookup(&good_revs, mb)) {
791 continue;
792 } else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {
793 handle_skipped_merge_base(mb);
794 } else {
795 printf("Bisecting: a merge base must be tested\n");
796 exit(bisect_checkout(mb, no_checkout));
800 free(rev);
801 free_commit_list(result);
804 static int check_ancestors(const char *prefix)
806 struct rev_info revs;
807 struct object_array pending_copy;
808 int res;
810 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
812 /* Save pending objects, so they can be cleaned up later. */
813 pending_copy = revs.pending;
814 revs.leak_pending = 1;
817 * bisect_common calls prepare_revision_walk right away, which
818 * (together with .leak_pending = 1) makes us the sole owner of
819 * the list of pending objects.
821 bisect_common(&revs);
822 res = (revs.commits != NULL);
824 /* Clean up objects used, as they will be reused. */
825 clear_commit_marks_for_object_array(&pending_copy, ALL_REV_FLAGS);
826 free(pending_copy.objects);
828 return res;
832 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
833 * ancestor of the "bad" rev.
835 * If that's not the case, we need to check the merge bases.
836 * If a merge base must be tested by the user, its source code will be
837 * checked out to be tested by the user and we will exit.
839 static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
841 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
842 struct stat st;
843 int fd;
845 if (!current_bad_oid)
846 die("a %s revision is needed", term_bad);
848 /* Check if file BISECT_ANCESTORS_OK exists. */
849 if (!stat(filename, &st) && S_ISREG(st.st_mode))
850 goto done;
852 /* Bisecting with no good rev is ok. */
853 if (good_revs.nr == 0)
854 goto done;
856 /* Check if all good revs are ancestor of the bad rev. */
857 if (check_ancestors(prefix))
858 check_merge_bases(no_checkout);
860 /* Create file BISECT_ANCESTORS_OK. */
861 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
862 if (fd < 0)
863 warning("could not create file '%s': %s",
864 filename, strerror(errno));
865 else
866 close(fd);
867 done:
868 free(filename);
872 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
874 static void show_diff_tree(const char *prefix, struct commit *commit)
876 struct rev_info opt;
878 /* diff-tree init */
879 init_revisions(&opt, prefix);
880 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
881 opt.abbrev = 0;
882 opt.diff = 1;
884 /* This is what "--pretty" does */
885 opt.verbose_header = 1;
886 opt.use_terminator = 0;
887 opt.commit_format = CMIT_FMT_DEFAULT;
889 /* diff-tree init */
890 if (!opt.diffopt.output_format)
891 opt.diffopt.output_format = DIFF_FORMAT_RAW;
893 log_tree_commit(&opt, commit);
897 * The terms used for this bisect session are stored in BISECT_TERMS.
898 * We read them and store them to adapt the messages accordingly.
899 * Default is bad/good.
901 void read_bisect_terms(const char **read_bad, const char **read_good)
903 struct strbuf str = STRBUF_INIT;
904 const char *filename = git_path("BISECT_TERMS");
905 FILE *fp = fopen(filename, "r");
907 if (!fp) {
908 if (errno == ENOENT) {
909 *read_bad = "bad";
910 *read_good = "good";
911 return;
912 } else {
913 die("could not read file '%s': %s", filename,
914 strerror(errno));
916 } else {
917 strbuf_getline(&str, fp, '\n');
918 *read_bad = strbuf_detach(&str, NULL);
919 strbuf_getline(&str, fp, '\n');
920 *read_good = strbuf_detach(&str, NULL);
922 strbuf_release(&str);
923 fclose(fp);
927 * We use the convention that exiting with an exit code 10 means that
928 * the bisection process finished successfully.
929 * In this case the calling shell script should exit 0.
931 * If no_checkout is non-zero, the bisection process does not
932 * checkout the trial commit but instead simply updates BISECT_HEAD.
934 int bisect_next_all(const char *prefix, int no_checkout)
936 struct rev_info revs;
937 struct commit_list *tried;
938 int reaches = 0, all = 0, nr, steps;
939 const unsigned char *bisect_rev;
941 read_bisect_terms(&term_bad, &term_good);
942 if (read_bisect_refs())
943 die("reading bisect refs failed");
945 check_good_are_ancestors_of_bad(prefix, no_checkout);
947 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
948 revs.limited = 1;
950 bisect_common(&revs);
952 revs.commits = find_bisection(revs.commits, &reaches, &all,
953 !!skipped_revs.nr);
954 revs.commits = managed_skipped(revs.commits, &tried);
956 if (!revs.commits) {
958 * We should exit here only if the "bad"
959 * commit is also a "skip" commit.
961 exit_if_skipped_commits(tried, NULL);
963 printf("%s was both %s and %s\n",
964 oid_to_hex(current_bad_oid),
965 term_good,
966 term_bad);
967 exit(1);
970 if (!all) {
971 fprintf(stderr, "No testable commit found.\n"
972 "Maybe you started with bad path parameters?\n");
973 exit(4);
976 bisect_rev = revs.commits->item->object.sha1;
978 if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
979 exit_if_skipped_commits(tried, current_bad_oid);
980 printf("%s is the first %s commit\n", sha1_to_hex(bisect_rev),
981 term_bad);
982 show_diff_tree(prefix, revs.commits->item);
983 /* This means the bisection process succeeded. */
984 exit(10);
987 nr = all - reaches - 1;
988 steps = estimate_bisect_steps(all);
989 printf("Bisecting: %d revision%s left to test after this "
990 "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
991 steps, (steps == 1 ? "" : "s"));
993 return bisect_checkout(bisect_rev, no_checkout);
996 static inline int log2i(int n)
998 int log2 = 0;
1000 for (; n > 1; n >>= 1)
1001 log2++;
1003 return log2;
1006 static inline int exp2i(int n)
1008 return 1 << n;
1012 * Estimate the number of bisect steps left (after the current step)
1014 * For any x between 0 included and 2^n excluded, the probability for
1015 * n - 1 steps left looks like:
1017 * P(2^n + x) == (2^n - x) / (2^n + x)
1019 * and P(2^n + x) < 0.5 means 2^n < 3x
1021 int estimate_bisect_steps(int all)
1023 int n, x, e;
1025 if (all < 3)
1026 return 0;
1028 n = log2i(all);
1029 e = exp2i(n);
1030 x = all - e;
1032 return (e < 3 * x) ? n : n - 1;