builtin-remote: Make "remote -v" display push urls
[git/mingw.git] / bisect.c
blobc43c120bdefe95bda60b913c5a52d0a942e9d3f6
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 "bisect.h"
12 struct sha1_array {
13 unsigned char (*sha1)[20];
14 int sha1_nr;
15 int sha1_alloc;
16 int sorted;
19 static struct sha1_array good_revs;
20 static struct sha1_array skipped_revs;
22 static const unsigned char *current_bad_sha1;
24 struct argv_array {
25 const char **argv;
26 int argv_nr;
27 int argv_alloc;
30 static const char *argv_diff_tree[] = {"diff-tree", "--pretty", NULL, NULL};
31 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
32 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
34 /* bits #0-15 in revision.h */
36 #define COUNTED (1u<<16)
39 * This is a truly stupid algorithm, but it's only
40 * used for bisection, and we just don't care enough.
42 * We care just barely enough to avoid recursing for
43 * non-merge entries.
45 static int count_distance(struct commit_list *entry)
47 int nr = 0;
49 while (entry) {
50 struct commit *commit = entry->item;
51 struct commit_list *p;
53 if (commit->object.flags & (UNINTERESTING | COUNTED))
54 break;
55 if (!(commit->object.flags & TREESAME))
56 nr++;
57 commit->object.flags |= COUNTED;
58 p = commit->parents;
59 entry = p;
60 if (p) {
61 p = p->next;
62 while (p) {
63 nr += count_distance(p);
64 p = p->next;
69 return nr;
72 static void clear_distance(struct commit_list *list)
74 while (list) {
75 struct commit *commit = list->item;
76 commit->object.flags &= ~COUNTED;
77 list = list->next;
81 #define DEBUG_BISECT 0
83 static inline int weight(struct commit_list *elem)
85 return *((int*)(elem->item->util));
88 static inline void weight_set(struct commit_list *elem, int weight)
90 *((int*)(elem->item->util)) = weight;
93 static int count_interesting_parents(struct commit *commit)
95 struct commit_list *p;
96 int count;
98 for (count = 0, p = commit->parents; p; p = p->next) {
99 if (p->item->object.flags & UNINTERESTING)
100 continue;
101 count++;
103 return count;
106 static inline int halfway(struct commit_list *p, int nr)
109 * Don't short-cut something we are not going to return!
111 if (p->item->object.flags & TREESAME)
112 return 0;
113 if (DEBUG_BISECT)
114 return 0;
116 * 2 and 3 are halfway of 5.
117 * 3 is halfway of 6 but 2 and 4 are not.
119 switch (2 * weight(p) - nr) {
120 case -1: case 0: case 1:
121 return 1;
122 default:
123 return 0;
127 #if !DEBUG_BISECT
128 #define show_list(a,b,c,d) do { ; } while (0)
129 #else
130 static void show_list(const char *debug, int counted, int nr,
131 struct commit_list *list)
133 struct commit_list *p;
135 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
137 for (p = list; p; p = p->next) {
138 struct commit_list *pp;
139 struct commit *commit = p->item;
140 unsigned flags = commit->object.flags;
141 enum object_type type;
142 unsigned long size;
143 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
144 char *ep, *sp;
146 fprintf(stderr, "%c%c%c ",
147 (flags & TREESAME) ? ' ' : 'T',
148 (flags & UNINTERESTING) ? 'U' : ' ',
149 (flags & COUNTED) ? 'C' : ' ');
150 if (commit->util)
151 fprintf(stderr, "%3d", weight(p));
152 else
153 fprintf(stderr, "---");
154 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
155 for (pp = commit->parents; pp; pp = pp->next)
156 fprintf(stderr, " %.*s", 8,
157 sha1_to_hex(pp->item->object.sha1));
159 sp = strstr(buf, "\n\n");
160 if (sp) {
161 sp += 2;
162 for (ep = sp; *ep && *ep != '\n'; ep++)
164 fprintf(stderr, " %.*s", (int)(ep - sp), sp);
166 fprintf(stderr, "\n");
169 #endif /* DEBUG_BISECT */
171 static struct commit_list *best_bisection(struct commit_list *list, int nr)
173 struct commit_list *p, *best;
174 int best_distance = -1;
176 best = list;
177 for (p = list; p; p = p->next) {
178 int distance;
179 unsigned flags = p->item->object.flags;
181 if (flags & TREESAME)
182 continue;
183 distance = weight(p);
184 if (nr - distance < distance)
185 distance = nr - distance;
186 if (distance > best_distance) {
187 best = p;
188 best_distance = distance;
192 return best;
195 struct commit_dist {
196 struct commit *commit;
197 int distance;
200 static int compare_commit_dist(const void *a_, const void *b_)
202 struct commit_dist *a, *b;
204 a = (struct commit_dist *)a_;
205 b = (struct commit_dist *)b_;
206 if (a->distance != b->distance)
207 return b->distance - a->distance; /* desc sort */
208 return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
211 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
213 struct commit_list *p;
214 struct commit_dist *array = xcalloc(nr, sizeof(*array));
215 int cnt, i;
217 for (p = list, cnt = 0; p; p = p->next) {
218 int distance;
219 unsigned flags = p->item->object.flags;
221 if (flags & TREESAME)
222 continue;
223 distance = weight(p);
224 if (nr - distance < distance)
225 distance = nr - distance;
226 array[cnt].commit = p->item;
227 array[cnt].distance = distance;
228 cnt++;
230 qsort(array, cnt, sizeof(*array), compare_commit_dist);
231 for (p = list, i = 0; i < cnt; i++) {
232 struct name_decoration *r = xmalloc(sizeof(*r) + 100);
233 struct object *obj = &(array[i].commit->object);
235 sprintf(r->name, "dist=%d", array[i].distance);
236 r->next = add_decoration(&name_decoration, obj, r);
237 p->item = array[i].commit;
238 p = p->next;
240 if (p)
241 p->next = NULL;
242 free(array);
243 return list;
247 * zero or positive weight is the number of interesting commits it can
248 * reach, including itself. Especially, weight = 0 means it does not
249 * reach any tree-changing commits (e.g. just above uninteresting one
250 * but traversal is with pathspec).
252 * weight = -1 means it has one parent and its distance is yet to
253 * be computed.
255 * weight = -2 means it has more than one parent and its distance is
256 * unknown. After running count_distance() first, they will get zero
257 * or positive distance.
259 static struct commit_list *do_find_bisection(struct commit_list *list,
260 int nr, int *weights,
261 int find_all)
263 int n, counted;
264 struct commit_list *p;
266 counted = 0;
268 for (n = 0, p = list; p; p = p->next) {
269 struct commit *commit = p->item;
270 unsigned flags = commit->object.flags;
272 p->item->util = &weights[n++];
273 switch (count_interesting_parents(commit)) {
274 case 0:
275 if (!(flags & TREESAME)) {
276 weight_set(p, 1);
277 counted++;
278 show_list("bisection 2 count one",
279 counted, nr, list);
282 * otherwise, it is known not to reach any
283 * tree-changing commit and gets weight 0.
285 break;
286 case 1:
287 weight_set(p, -1);
288 break;
289 default:
290 weight_set(p, -2);
291 break;
295 show_list("bisection 2 initialize", counted, nr, list);
298 * If you have only one parent in the resulting set
299 * then you can reach one commit more than that parent
300 * can reach. So we do not have to run the expensive
301 * count_distance() for single strand of pearls.
303 * However, if you have more than one parents, you cannot
304 * just add their distance and one for yourself, since
305 * they usually reach the same ancestor and you would
306 * end up counting them twice that way.
308 * So we will first count distance of merges the usual
309 * way, and then fill the blanks using cheaper algorithm.
311 for (p = list; p; p = p->next) {
312 if (p->item->object.flags & UNINTERESTING)
313 continue;
314 if (weight(p) != -2)
315 continue;
316 weight_set(p, count_distance(p));
317 clear_distance(list);
319 /* Does it happen to be at exactly half-way? */
320 if (!find_all && halfway(p, nr))
321 return p;
322 counted++;
325 show_list("bisection 2 count_distance", counted, nr, list);
327 while (counted < nr) {
328 for (p = list; p; p = p->next) {
329 struct commit_list *q;
330 unsigned flags = p->item->object.flags;
332 if (0 <= weight(p))
333 continue;
334 for (q = p->item->parents; q; q = q->next) {
335 if (q->item->object.flags & UNINTERESTING)
336 continue;
337 if (0 <= weight(q))
338 break;
340 if (!q)
341 continue;
344 * weight for p is unknown but q is known.
345 * add one for p itself if p is to be counted,
346 * otherwise inherit it from q directly.
348 if (!(flags & TREESAME)) {
349 weight_set(p, weight(q)+1);
350 counted++;
351 show_list("bisection 2 count one",
352 counted, nr, list);
354 else
355 weight_set(p, weight(q));
357 /* Does it happen to be at exactly half-way? */
358 if (!find_all && halfway(p, nr))
359 return p;
363 show_list("bisection 2 counted all", counted, nr, list);
365 if (!find_all)
366 return best_bisection(list, nr);
367 else
368 return best_bisection_sorted(list, nr);
371 struct commit_list *find_bisection(struct commit_list *list,
372 int *reaches, int *all,
373 int find_all)
375 int nr, on_list;
376 struct commit_list *p, *best, *next, *last;
377 int *weights;
379 show_list("bisection 2 entry", 0, 0, list);
382 * Count the number of total and tree-changing items on the
383 * list, while reversing the list.
385 for (nr = on_list = 0, last = NULL, p = list;
387 p = next) {
388 unsigned flags = p->item->object.flags;
390 next = p->next;
391 if (flags & UNINTERESTING)
392 continue;
393 p->next = last;
394 last = p;
395 if (!(flags & TREESAME))
396 nr++;
397 on_list++;
399 list = last;
400 show_list("bisection 2 sorted", 0, nr, list);
402 *all = nr;
403 weights = xcalloc(on_list, sizeof(*weights));
405 /* Do the real work of finding bisection commit. */
406 best = do_find_bisection(list, nr, weights, find_all);
407 if (best) {
408 if (!find_all)
409 best->next = NULL;
410 *reaches = weight(best);
412 free(weights);
413 return best;
416 static void argv_array_push(struct argv_array *array, const char *string)
418 ALLOC_GROW(array->argv, array->argv_nr + 1, array->argv_alloc);
419 array->argv[array->argv_nr++] = string;
422 static void argv_array_push_sha1(struct argv_array *array,
423 const unsigned char *sha1,
424 const char *format)
426 struct strbuf buf = STRBUF_INIT;
427 strbuf_addf(&buf, format, sha1_to_hex(sha1));
428 argv_array_push(array, strbuf_detach(&buf, NULL));
431 static void sha1_array_push(struct sha1_array *array,
432 const unsigned char *sha1)
434 ALLOC_GROW(array->sha1, array->sha1_nr + 1, array->sha1_alloc);
435 hashcpy(array->sha1[array->sha1_nr++], sha1);
438 static int register_ref(const char *refname, const unsigned char *sha1,
439 int flags, void *cb_data)
441 if (!strcmp(refname, "bad")) {
442 current_bad_sha1 = sha1;
443 } else if (!prefixcmp(refname, "good-")) {
444 sha1_array_push(&good_revs, sha1);
445 } else if (!prefixcmp(refname, "skip-")) {
446 sha1_array_push(&skipped_revs, sha1);
449 return 0;
452 static int read_bisect_refs(void)
454 return for_each_ref_in("refs/bisect/", register_ref, NULL);
457 void read_bisect_paths(struct argv_array *array)
459 struct strbuf str = STRBUF_INIT;
460 const char *filename = git_path("BISECT_NAMES");
461 FILE *fp = fopen(filename, "r");
463 if (!fp)
464 die("Could not open file '%s': %s", filename, strerror(errno));
466 while (strbuf_getline(&str, fp, '\n') != EOF) {
467 char *quoted;
468 int res;
470 strbuf_trim(&str);
471 quoted = strbuf_detach(&str, NULL);
472 res = sq_dequote_to_argv(quoted, &array->argv,
473 &array->argv_nr, &array->argv_alloc);
474 if (res)
475 die("Badly quoted content in file '%s': %s",
476 filename, quoted);
479 strbuf_release(&str);
480 fclose(fp);
483 static int array_cmp(const void *a, const void *b)
485 return hashcmp(a, b);
488 static void sort_sha1_array(struct sha1_array *array)
490 qsort(array->sha1, array->sha1_nr, sizeof(*array->sha1), array_cmp);
492 array->sorted = 1;
495 static const unsigned char *sha1_access(size_t index, void *table)
497 unsigned char (*array)[20] = table;
498 return array[index];
501 static int lookup_sha1_array(struct sha1_array *array,
502 const unsigned char *sha1)
504 if (!array->sorted)
505 sort_sha1_array(array);
507 return sha1_pos(sha1, array->sha1, array->sha1_nr, sha1_access);
510 static char *join_sha1_array_hex(struct sha1_array *array, char delim)
512 struct strbuf joined_hexs = STRBUF_INIT;
513 int i;
515 for (i = 0; i < array->sha1_nr; i++) {
516 strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
517 if (i + 1 < array->sha1_nr)
518 strbuf_addch(&joined_hexs, delim);
521 return strbuf_detach(&joined_hexs, NULL);
524 struct commit_list *filter_skipped(struct commit_list *list,
525 struct commit_list **tried,
526 int show_all)
528 struct commit_list *filtered = NULL, **f = &filtered;
530 *tried = NULL;
532 if (!skipped_revs.sha1_nr)
533 return list;
535 while (list) {
536 struct commit_list *next = list->next;
537 list->next = NULL;
538 if (0 <= lookup_sha1_array(&skipped_revs,
539 list->item->object.sha1)) {
540 /* Move current to tried list */
541 *tried = list;
542 tried = &list->next;
543 } else {
544 if (!show_all)
545 return list;
546 /* Move current to filtered list */
547 *f = list;
548 f = &list->next;
550 list = next;
553 return filtered;
556 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
557 const char *bad_format, const char *good_format,
558 int read_paths)
560 struct argv_array rev_argv = { NULL, 0, 0 };
561 int i;
563 init_revisions(revs, prefix);
564 revs->abbrev = 0;
565 revs->commit_format = CMIT_FMT_UNSPECIFIED;
567 /* rev_argv.argv[0] will be ignored by setup_revisions */
568 argv_array_push(&rev_argv, xstrdup("bisect_rev_setup"));
569 argv_array_push_sha1(&rev_argv, current_bad_sha1, bad_format);
570 for (i = 0; i < good_revs.sha1_nr; i++)
571 argv_array_push_sha1(&rev_argv, good_revs.sha1[i],
572 good_format);
573 argv_array_push(&rev_argv, xstrdup("--"));
574 if (read_paths)
575 read_bisect_paths(&rev_argv);
576 argv_array_push(&rev_argv, NULL);
578 setup_revisions(rev_argv.argv_nr, rev_argv.argv, revs, NULL);
581 static void bisect_common(struct rev_info *revs)
583 if (prepare_revision_walk(revs))
584 die("revision walk setup failed");
585 if (revs->tree_objects)
586 mark_edges_uninteresting(revs->commits, revs, NULL);
589 static void exit_if_skipped_commits(struct commit_list *tried,
590 const unsigned char *bad)
592 if (!tried)
593 return;
595 printf("There are only 'skip'ped commits left to test.\n"
596 "The first bad commit could be any of:\n");
597 print_commit_list(tried, "%s\n", "%s\n");
598 if (bad)
599 printf("%s\n", sha1_to_hex(bad));
600 printf("We cannot bisect more!\n");
601 exit(2);
604 static int is_expected_rev(const unsigned char *sha1)
606 const char *filename = git_path("BISECT_EXPECTED_REV");
607 struct stat st;
608 struct strbuf str = STRBUF_INIT;
609 FILE *fp;
610 int res = 0;
612 if (stat(filename, &st) || !S_ISREG(st.st_mode))
613 return 0;
615 fp = fopen(filename, "r");
616 if (!fp)
617 return 0;
619 if (strbuf_getline(&str, fp, '\n') != EOF)
620 res = !strcmp(str.buf, sha1_to_hex(sha1));
622 strbuf_release(&str);
623 fclose(fp);
625 return res;
628 static void mark_expected_rev(char *bisect_rev_hex)
630 int len = strlen(bisect_rev_hex);
631 const char *filename = git_path("BISECT_EXPECTED_REV");
632 int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
634 if (fd < 0)
635 die("could not create file '%s': %s",
636 filename, strerror(errno));
638 bisect_rev_hex[len] = '\n';
639 write_or_die(fd, bisect_rev_hex, len + 1);
640 bisect_rev_hex[len] = '\0';
642 if (close(fd) < 0)
643 die("closing file %s: %s", filename, strerror(errno));
646 static int bisect_checkout(char *bisect_rev_hex)
648 int res;
650 mark_expected_rev(bisect_rev_hex);
652 argv_checkout[2] = bisect_rev_hex;
653 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
654 if (res)
655 exit(res);
657 argv_show_branch[1] = bisect_rev_hex;
658 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
661 static struct commit *get_commit_reference(const unsigned char *sha1)
663 struct commit *r = lookup_commit_reference(sha1);
664 if (!r)
665 die("Not a valid commit name %s", sha1_to_hex(sha1));
666 return r;
669 static struct commit **get_bad_and_good_commits(int *rev_nr)
671 int len = 1 + good_revs.sha1_nr;
672 struct commit **rev = xmalloc(len * sizeof(*rev));
673 int i, n = 0;
675 rev[n++] = get_commit_reference(current_bad_sha1);
676 for (i = 0; i < good_revs.sha1_nr; i++)
677 rev[n++] = get_commit_reference(good_revs.sha1[i]);
678 *rev_nr = n;
680 return rev;
683 static void handle_bad_merge_base(void)
685 if (is_expected_rev(current_bad_sha1)) {
686 char *bad_hex = sha1_to_hex(current_bad_sha1);
687 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
689 fprintf(stderr, "The merge base %s is bad.\n"
690 "This means the bug has been fixed "
691 "between %s and [%s].\n",
692 bad_hex, bad_hex, good_hex);
694 exit(3);
697 fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
698 "git bisect cannot work properly in this case.\n"
699 "Maybe you mistake good and bad revs?\n");
700 exit(1);
703 void handle_skipped_merge_base(const unsigned char *mb)
705 char *mb_hex = sha1_to_hex(mb);
706 char *bad_hex = sha1_to_hex(current_bad_sha1);
707 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
709 fprintf(stderr, "Warning: the merge base between %s and [%s] "
710 "must be skipped.\n"
711 "So we cannot be sure the first bad commit is "
712 "between %s and %s.\n"
713 "We continue anyway.\n",
714 bad_hex, good_hex, mb_hex, bad_hex);
715 free(good_hex);
719 * "check_merge_bases" checks that merge bases are not "bad".
721 * - If one is "bad", it means the user assumed something wrong
722 * and we must exit with a non 0 error code.
723 * - If one is "good", that's good, we have nothing to do.
724 * - If one is "skipped", we can't know but we should warn.
725 * - If we don't know, we should check it out and ask the user to test.
727 static void check_merge_bases(void)
729 struct commit_list *result;
730 int rev_nr;
731 struct commit **rev = get_bad_and_good_commits(&rev_nr);
733 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
735 for (; result; result = result->next) {
736 const unsigned char *mb = result->item->object.sha1;
737 if (!hashcmp(mb, current_bad_sha1)) {
738 handle_bad_merge_base();
739 } else if (0 <= lookup_sha1_array(&good_revs, mb)) {
740 continue;
741 } else if (0 <= lookup_sha1_array(&skipped_revs, mb)) {
742 handle_skipped_merge_base(mb);
743 } else {
744 printf("Bisecting: a merge base must be tested\n");
745 exit(bisect_checkout(sha1_to_hex(mb)));
749 free(rev);
750 free_commit_list(result);
753 static int check_ancestors(const char *prefix)
755 struct rev_info revs;
756 struct object_array pending_copy;
757 int i, res;
759 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
761 /* Save pending objects, so they can be cleaned up later. */
762 memset(&pending_copy, 0, sizeof(pending_copy));
763 for (i = 0; i < revs.pending.nr; i++)
764 add_object_array(revs.pending.objects[i].item,
765 revs.pending.objects[i].name,
766 &pending_copy);
768 bisect_common(&revs);
769 res = (revs.commits != NULL);
771 /* Clean up objects used, as they will be reused. */
772 for (i = 0; i < pending_copy.nr; i++) {
773 struct object *o = pending_copy.objects[i].item;
774 unparse_commit((struct commit *)o);
777 return res;
781 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
782 * ancestor of the "bad" rev.
784 * If that's not the case, we need to check the merge bases.
785 * If a merge base must be tested by the user, its source code will be
786 * checked out to be tested by the user and we will exit.
788 static void check_good_are_ancestors_of_bad(const char *prefix)
790 const char *filename = git_path("BISECT_ANCESTORS_OK");
791 struct stat st;
792 int fd;
794 if (!current_bad_sha1)
795 die("a bad revision is needed");
797 /* Check if file BISECT_ANCESTORS_OK exists. */
798 if (!stat(filename, &st) && S_ISREG(st.st_mode))
799 return;
801 /* Bisecting with no good rev is ok. */
802 if (good_revs.sha1_nr == 0)
803 return;
805 /* Check if all good revs are ancestor of the bad rev. */
806 if (check_ancestors(prefix))
807 check_merge_bases();
809 /* Create file BISECT_ANCESTORS_OK. */
810 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
811 if (fd < 0)
812 warning("could not create file '%s': %s",
813 filename, strerror(errno));
814 else
815 close(fd);
819 * We use the convention that exiting with an exit code 10 means that
820 * the bisection process finished successfully.
821 * In this case the calling shell script should exit 0.
823 int bisect_next_all(const char *prefix)
825 struct rev_info revs;
826 struct commit_list *tried;
827 int reaches = 0, all = 0, nr;
828 const unsigned char *bisect_rev;
829 char bisect_rev_hex[41];
831 if (read_bisect_refs())
832 die("reading bisect refs failed");
834 check_good_are_ancestors_of_bad(prefix);
836 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
837 revs.limited = 1;
839 bisect_common(&revs);
841 revs.commits = find_bisection(revs.commits, &reaches, &all,
842 !!skipped_revs.sha1_nr);
843 revs.commits = filter_skipped(revs.commits, &tried, 0);
845 if (!revs.commits) {
847 * We should exit here only if the "bad"
848 * commit is also a "skip" commit.
850 exit_if_skipped_commits(tried, NULL);
852 printf("%s was both good and bad\n",
853 sha1_to_hex(current_bad_sha1));
854 exit(1);
857 bisect_rev = revs.commits->item->object.sha1;
858 memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
860 if (!hashcmp(bisect_rev, current_bad_sha1)) {
861 exit_if_skipped_commits(tried, current_bad_sha1);
862 printf("%s is first bad commit\n", bisect_rev_hex);
863 argv_diff_tree[2] = bisect_rev_hex;
864 run_command_v_opt(argv_diff_tree, RUN_GIT_CMD);
865 /* This means the bisection process succeeded. */
866 exit(10);
869 nr = all - reaches - 1;
870 printf("Bisecting: %d revisions left to test after this "
871 "(roughly %d steps)\n", nr, estimate_bisect_steps(all));
873 return bisect_checkout(bisect_rev_hex);