#include "cache.h"

#include "commit.h"

#include "diff.h"

#include "revision.h"

#include "refs.h"

#include "list-objects.h"

#include "quote.h"

#include "sha1-lookup.h"

#include "run-command.h"

#include "log-tree.h"

#include "bisect.h"

#include "sha1-array.h"

#include "argv-array.h"

static struct sha1_array good_revs;

static struct sha1_array skipped_revs;

static struct object_id *current_bad_oid;

static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};

static const char *argv_show_branch[] = {"show-branch", NULL, NULL};

static const char *term_bad;

static const char *term_good;

/* Remember to update object flag allocation in object.h */

#define COUNTED (1u<<16)

/*

* This is a truly stupid algorithm, but it's only

* used for bisection, and we just don't care enough.

*

* We care just barely enough to avoid recursing for

* non-merge entries.

*/

static int count_distance(struct commit_list *entry)

{

int nr = 0;

while (entry) {

struct commit *commit = entry->item;

struct commit_list *p;

if (commit->object.flags & (UNINTERESTING | COUNTED))

break;

if (!(commit->object.flags & TREESAME))

nr++;

commit->object.flags |= COUNTED;

p = commit->parents;

entry = p;

if (p) {

p = p->next;

while (p) {

nr += count_distance(p);

p = p->next;

}

}

}

return nr;

}

static void clear_distance(struct commit_list *list)

{

while (list) {

struct commit *commit = list->item;

commit->object.flags &= ~COUNTED;

list = list->next;

}

}

#define DEBUG_BISECT 0

static inline int weight(struct commit_list *elem)

{

return *((int*)(elem->item->util));

}

static inline void weight_set(struct commit_list *elem, int weight)

{

*((int*)(elem->item->util)) = weight;

}

static int count_interesting_parents(struct commit *commit)

{

struct commit_list *p;

int count;

for (count = 0, p = commit->parents; p; p = p->next) {

if (p->item->object.flags & UNINTERESTING)

continue;

count++;

}

return count;

}

static inline int halfway(struct commit_list *p, int nr)

{

/*

* Don't short-cut something we are not going to return!

*/

if (p->item->object.flags & TREESAME)

return 0;

if (DEBUG_BISECT)

return 0;

/*

* 2 and 3 are halfway of 5.

* 3 is halfway of 6 but 2 and 4 are not.

*/

switch (2 * weight(p) - nr) {

case -1: case 0: case 1:

return 1;

default:

return 0;

}

}

#if !DEBUG_BISECT

#define show_list(a,b,c,d) do { ; } while (0)

#else

static void show_list(const char *debug, int counted, int nr,

struct commit_list *list)

{

struct commit_list *p;

fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);

for (p = list; p; p = p->next) {

struct commit_list *pp;

struct commit *commit = p->item;

unsigned flags = commit->object.flags;

enum object_type type;

unsigned long size;

char *buf = read_sha1_file(commit->object.sha1, &type, &size);

const char *subject_start;

int subject_len;

fprintf(stderr, "%c%c%c ",

(flags & TREESAME) ? ' ' : 'T',

(flags & UNINTERESTING) ? 'U' : ' ',

(flags & COUNTED) ? 'C' : ' ');

if (commit->util)

fprintf(stderr, "%3d", weight(p));

else

fprintf(stderr, "---");

fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));

for (pp = commit->parents; pp; pp = pp->next)

fprintf(stderr, " %.*s", 8,

sha1_to_hex(pp->item->object.sha1));

subject_len = find_commit_subject(buf, &subject_start);

if (subject_len)

fprintf(stderr, " %.*s", subject_len, subject_start);

fprintf(stderr, "\n");

}

}

#endif /* DEBUG_BISECT */

static struct commit_list *best_bisection(struct commit_list *list, int nr)

{

struct commit_list *p, *best;

int best_distance = -1;

best = list;

for (p = list; p; p = p->next) {

int distance;

unsigned flags = p->item->object.flags;

if (flags & TREESAME)

continue;

distance = weight(p);

if (nr - distance < distance)

distance = nr - distance;

if (distance > best_distance) {

best = p;

best_distance = distance;

}

}

return best;

}

struct commit_dist {

struct commit *commit;

int distance;

};

static int compare_commit_dist(const void *a_, const void *b_)

{

struct commit_dist *a, *b;

a = (struct commit_dist *)a_;

b = (struct commit_dist *)b_;

if (a->distance != b->distance)

return b->distance - a->distance; /* desc sort */

return hashcmp(a->commit->object.sha1, b->commit->object.sha1);

}

static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)

{

struct commit_list *p;

struct commit_dist *array = xcalloc(nr, sizeof(*array));

int cnt, i;

for (p = list, cnt = 0; p; p = p->next) {

int distance;

unsigned flags = p->item->object.flags;

if (flags & TREESAME)

continue;

distance = weight(p);

if (nr - distance < distance)

distance = nr - distance;

array[cnt].commit = p->item;

array[cnt].distance = distance;

cnt++;

}

qsort(array, cnt, sizeof(*array), compare_commit_dist);

for (p = list, i = 0; i < cnt; i++) {

char buf[100]; /* enough for dist=%d */

struct object *obj = &(array[i].commit->object);

snprintf(buf, sizeof(buf), "dist=%d", array[i].distance);

add_name_decoration(DECORATION_NONE, buf, obj);

p->item = array[i].commit;

p = p->next;

}

if (p)

p->next = NULL;

free(array);

return list;

}

/*

* zero or positive weight is the number of interesting commits it can

* reach, including itself. Especially, weight = 0 means it does not

* reach any tree-changing commits (e.g. just above uninteresting one

* but traversal is with pathspec).

*

* weight = -1 means it has one parent and its distance is yet to

* be computed.

*

* weight = -2 means it has more than one parent and its distance is

* unknown. After running count_distance() first, they will get zero

* or positive distance.

*/

static struct commit_list *do_find_bisection(struct commit_list *list,

int nr, int *weights,

int find_all)

{

int n, counted;

struct commit_list *p;

counted = 0;

for (n = 0, p = list; p; p = p->next) {

struct commit *commit = p->item;

unsigned flags = commit->object.flags;

p->item->util = &weights[n++];

switch (count_interesting_parents(commit)) {

case 0:

if (!(flags & TREESAME)) {

weight_set(p, 1);

counted++;

show_list("bisection 2 count one",

counted, nr, list);

}

/*

* otherwise, it is known not to reach any

* tree-changing commit and gets weight 0.

*/

break;

case 1:

weight_set(p, -1);

break;

default:

weight_set(p, -2);

break;

}

}

show_list("bisection 2 initialize", counted, nr, list);

/*

* If you have only one parent in the resulting set

* then you can reach one commit more than that parent

* can reach. So we do not have to run the expensive

* count_distance() for single strand of pearls.

*

* However, if you have more than one parents, you cannot

* just add their distance and one for yourself, since

* they usually reach the same ancestor and you would

* end up counting them twice that way.

*

* So we will first count distance of merges the usual

* way, and then fill the blanks using cheaper algorithm.

*/

for (p = list; p; p = p->next) {

if (p->item->object.flags & UNINTERESTING)

continue;

if (weight(p) != -2)

continue;

weight_set(p, count_distance(p));

clear_distance(list);

/* Does it happen to be at exactly half-way? */

if (!find_all && halfway(p, nr))

return p;

counted++;

}

show_list("bisection 2 count_distance", counted, nr, list);

while (counted < nr) {

for (p = list; p; p = p->next) {

struct commit_list *q;

unsigned flags = p->item->object.flags;

if (0 <= weight(p))

continue;

for (q = p->item->parents; q; q = q->next) {

if (q->item->object.flags & UNINTERESTING)

continue;

if (0 <= weight(q))

break;

}

if (!q)

continue;

/*

* weight for p is unknown but q is known.

* add one for p itself if p is to be counted,

* otherwise inherit it from q directly.

*/

if (!(flags & TREESAME)) {

weight_set(p, weight(q)+1);

counted++;

show_list("bisection 2 count one",

counted, nr, list);

}

else

weight_set(p, weight(q));

/* Does it happen to be at exactly half-way? */

if (!find_all && halfway(p, nr))

return p;

}

}

show_list("bisection 2 counted all", counted, nr, list);

if (!find_all)

return best_bisection(list, nr);

else

return best_bisection_sorted(list, nr);

}

struct commit_list *find_bisection(struct commit_list *list,

int *reaches, int *all,

int find_all)

{

int nr, on_list;

struct commit_list *p, *best, *next, *last;

int *weights;

show_list("bisection 2 entry", 0, 0, list);

/*

* Count the number of total and tree-changing items on the

* list, while reversing the list.

*/

for (nr = on_list = 0, last = NULL, p = list;

p;

p = next) {

unsigned flags = p->item->object.flags;

next = p->next;

if (flags & UNINTERESTING)

continue;

p->next = last;

last = p;

if (!(flags & TREESAME))

nr++;

on_list++;

}

list = last;

show_list("bisection 2 sorted", 0, nr, list);

*all = nr;

weights = xcalloc(on_list, sizeof(*weights));

/* Do the real work of finding bisection commit. */

best = do_find_bisection(list, nr, weights, find_all);

if (best) {

if (!find_all)

best->next = NULL;

*reaches = weight(best);

}

free(weights);

return best;

}

static int register_ref(const char *refname, const struct object_id *oid,

int flags, void *cb_data)

{

struct strbuf good_prefix = STRBUF_INIT;

strbuf_addstr(&good_prefix, term_good);

strbuf_addstr(&good_prefix, "-");

if (!strcmp(refname, term_bad)) {

current_bad_oid = xmalloc(sizeof(*current_bad_oid));

oidcpy(current_bad_oid, oid);

} else if (starts_with(refname, good_prefix.buf)) {

sha1_array_append(&good_revs, oid->hash);

} else if (starts_with(refname, "skip-")) {

sha1_array_append(&skipped_revs, oid->hash);

}

strbuf_release(&good_prefix);

return 0;

}

static int read_bisect_refs(void)

{

return for_each_ref_in("refs/bisect/", register_ref, NULL);

}

static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")

static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")

static void read_bisect_paths(struct argv_array *array)

{

struct strbuf str = STRBUF_INIT;

const char *filename = git_path_bisect_names();

FILE *fp = fopen(filename, "r");

if (!fp)

die_errno("Could not open file '%s'", filename);

while (strbuf_getline(&str, fp, '\n') != EOF) {

strbuf_trim(&str);

if (sq_dequote_to_argv_array(str.buf, array))

die("Badly quoted content in file '%s': %s",

filename, str.buf);

}

strbuf_release(&str);

fclose(fp);

}

static char *join_sha1_array_hex(struct sha1_array *array, char delim)

{

struct strbuf joined_hexs = STRBUF_INIT;

int i;

for (i = 0; i < array->nr; i++) {

strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));

if (i + 1 < array->nr)

strbuf_addch(&joined_hexs, delim);

}

return strbuf_detach(&joined_hexs, NULL);

}

/*

* In this function, passing a not NULL skipped_first is very special.

* It means that we want to know if the first commit in the list is

* skipped because we will want to test a commit away from it if it is

* indeed skipped.

* So if the first commit is skipped, we cannot take the shortcut to

* just "return list" when we find the first non skipped commit, we

* have to return a fully filtered list.

*

* We use (*skipped_first == -1) to mean "it has been found that the

* first commit is not skipped". In this case *skipped_first is set back

* to 0 just before the function returns.

*/

struct commit_list *filter_skipped(struct commit_list *list,

int *skipped_first)

{

struct commit_list *filtered = NULL, **f = &filtered;

*tried = NULL;

if (skipped_first)

*skipped_first = 0;

if (count)

*count = 0;

if (!skipped_revs.nr)

return list;

while (list) {

struct commit_list *next = list->next;

list->next = NULL;

if (0 <= sha1_array_lookup(&skipped_revs,

list->item->object.sha1)) {

if (skipped_first && !*skipped_first)

*skipped_first = 1;

/* Move current to tried list */

*tried = list;

tried = &list->next;

} else {

if (!show_all) {

if (!skipped_first || !*skipped_first)

return list;

} else if (skipped_first && !*skipped_first) {

/* This means we know it's not skipped */

*skipped_first = -1;

}

/* Move current to filtered list */

*f = list;

f = &list->next;

if (count)

(*count)++;

}

list = next;

}

if (skipped_first && *skipped_first == -1)

*skipped_first = 0;

return filtered;

}

#define PRN_MODULO 32768

/*

* This is a pseudo random number generator based on "man 3 rand".

* It is not used properly because the seed is the argument and it

* is increased by one between each call, but that should not matter

* for this application.

*/

static unsigned get_prn(unsigned count) {

count = count * 1103515245 + 12345;

return (count/65536) % PRN_MODULO;

}

/*

* Custom integer square root from

* http://en.wikipedia.org/wiki/Integer_square_root

*/

static int sqrti(int val)

{

float d, x = val;

if (val == 0)

return 0;

do {

float y = (x + (float)val / x) / 2;

d = (y > x) ? y - x : x - y;

x = y;

} while (d >= 0.5);

return (int)x;

}

static struct commit_list *skip_away(struct commit_list *list, int count)

{

struct commit_list *cur, *previous;

int prn, index, i;

prn = get_prn(count);

index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);

cur = list;

previous = NULL;

for (i = 0; cur; cur = cur->next, i++) {

if (i == index) {

if (hashcmp(cur->item->object.sha1, current_bad_oid->hash))

return cur;

if (previous)

return previous;

return list;

}

previous = cur;

}

return list;

}

static struct commit_list *managed_skipped(struct commit_list *list,

struct commit_list **tried)

{

int count, skipped_first;

*tried = NULL;

if (!skipped_revs.nr)

return list;

list = filter_skipped(list, tried, 0, &count, &skipped_first);

if (!skipped_first)

return list;

return skip_away(list, count);

}

static void bisect_rev_setup(struct rev_info *revs, const char *prefix,

const char *bad_format, const char *good_format,

int read_paths)

{

struct argv_array rev_argv = ARGV_ARRAY_INIT;

int i;

init_revisions(revs, prefix);

revs->abbrev = 0;

revs->commit_format = CMIT_FMT_UNSPECIFIED;

/* rev_argv.argv[0] will be ignored by setup_revisions */

argv_array_push(&rev_argv, "bisect_rev_setup");

argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));

for (i = 0; i < good_revs.nr; i++)

argv_array_pushf(&rev_argv, good_format,

sha1_to_hex(good_revs.sha1[i]));

argv_array_push(&rev_argv, "--");

if (read_paths)

read_bisect_paths(&rev_argv);

setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);

/* XXX leak rev_argv, as "revs" may still be pointing to it */

}

static void bisect_common(struct rev_info *revs)

{

if (prepare_revision_walk(revs))

die("revision walk setup failed");

if (revs->tree_objects)

mark_edges_uninteresting(revs, NULL);

}

static void exit_if_skipped_commits(struct commit_list *tried,

const struct object_id *bad)

{

if (!tried)

return;

printf("There are only 'skip'ped commits left to test.\n"

"The first %s commit could be any of:\n", term_bad);

print_commit_list(tried, "%s\n", "%s\n");

if (bad)

printf("%s\n", oid_to_hex(bad));

printf("We cannot bisect more!\n");

exit(2);

}

static int is_expected_rev(const struct object_id *oid)

{

const char *filename = git_path_bisect_expected_rev();

struct stat st;

struct strbuf str = STRBUF_INIT;

FILE *fp;

int res = 0;

if (stat(filename, &st) || !S_ISREG(st.st_mode))

return 0;

fp = fopen(filename, "r");

if (!fp)

return 0;

if (strbuf_getline(&str, fp, '\n') != EOF)

res = !strcmp(str.buf, oid_to_hex(oid));

strbuf_release(&str);

fclose(fp);

return res;

}

static int bisect_checkout(const unsigned char *bisect_rev, int no_checkout)

{

char bisect_rev_hex[GIT_SHA1_HEXSZ + 1];

memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);

update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);

argv_checkout[2] = bisect_rev_hex;

if (no_checkout) {

update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);

} else {

int res;

res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);

if (res)

exit(res);

}

argv_show_branch[1] = bisect_rev_hex;

return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);

}

static struct commit *get_commit_reference(const unsigned char *sha1)

{

struct commit *r = lookup_commit_reference(sha1);

if (!r)

die("Not a valid commit name %s", sha1_to_hex(sha1));

return r;

}

static struct commit **get_bad_and_good_commits(int *rev_nr)

{

int len = 1 + good_revs.nr;

struct commit **rev = xmalloc(len * sizeof(*rev));

int i, n = 0;

rev[n++] = get_commit_reference(current_bad_oid->hash);

for (i = 0; i < good_revs.nr; i++)

rev[n++] = get_commit_reference(good_revs.sha1[i]);

*rev_nr = n;

return rev;

}

static void handle_bad_merge_base(void)

{

if (is_expected_rev(current_bad_oid)) {

char *bad_hex = oid_to_hex(current_bad_oid);

char *good_hex = join_sha1_array_hex(&good_revs, ' ');

if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {

fprintf(stderr, "The merge base %s is bad.\n"

"This means the bug has been fixed "

"between %s and [%s].\n",

bad_hex, bad_hex, good_hex);

} else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {

fprintf(stderr, "The merge base %s is new.\n"

"The property has changed "

"between %s and [%s].\n",

bad_hex, bad_hex, good_hex);

} else {

fprintf(stderr, "The merge base %s is %s.\n"

"This means the first '%s' commit is "

"between %s and [%s].\n",

bad_hex, term_bad, term_good, bad_hex, good_hex);

}

exit(3);

}

fprintf(stderr, "Some %s revs are not ancestor of the %s rev.\n"

"git bisect cannot work properly in this case.\n"

"Maybe you mistook %s and %s revs?\n",

term_good, term_bad, term_good, term_bad);

exit(1);

}

static void handle_skipped_merge_base(const unsigned char *mb)

{

char *mb_hex = sha1_to_hex(mb);

char *bad_hex = sha1_to_hex(current_bad_oid->hash);

char *good_hex = join_sha1_array_hex(&good_revs, ' ');

warning("the merge base between %s and [%s] "

"must be skipped.\n"

"So we cannot be sure the first %s commit is "

"between %s and %s.\n"

"We continue anyway.",

bad_hex, good_hex, term_bad, mb_hex, bad_hex);

free(good_hex);

}

/*

* "check_merge_bases" checks that merge bases are not "bad" (or "new").

*

* - If one is "bad" (or "new"), it means the user assumed something wrong

* and we must exit with a non 0 error code.

* - If one is "good" (or "old"), that's good, we have nothing to do.

* - If one is "skipped", we can't know but we should warn.

* - If we don't know, we should check it out and ask the user to test.

*/

static void check_merge_bases(int no_checkout)

{

struct commit_list *result;

int rev_nr;

struct commit **rev = get_bad_and_good_commits(&rev_nr);

result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);

for (; result; result = result->next) {

const unsigned char *mb = result->item->object.sha1;

if (!hashcmp(mb, current_bad_oid->hash)) {

handle_bad_merge_base();

} else if (0 <= sha1_array_lookup(&good_revs, mb)) {

continue;

} else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {

handle_skipped_merge_base(mb);

} else {

printf("Bisecting: a merge base must be tested\n");

exit(bisect_checkout(mb, no_checkout));

}

}

free(rev);

free_commit_list(result);

}

static int check_ancestors(const char *prefix)

{

struct rev_info revs;

struct object_array pending_copy;

int res;

bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);

/* Save pending objects, so they can be cleaned up later. */

pending_copy = revs.pending;

revs.leak_pending = 1;

/*

* bisect_common calls prepare_revision_walk right away, which

* (together with .leak_pending = 1) makes us the sole owner of

* the list of pending objects.

*/

bisect_common(&revs);

res = (revs.commits != NULL);

/* Clean up objects used, as they will be reused. */

clear_commit_marks_for_object_array(&pending_copy, ALL_REV_FLAGS);

free(pending_copy.objects);

return res;

}

/*

* "check_good_are_ancestors_of_bad" checks that all "good" revs are

* ancestor of the "bad" rev.

*

* If that's not the case, we need to check the merge bases.

* If a merge base must be tested by the user, its source code will be

* checked out to be tested by the user and we will exit.

*/

static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)

{

char *filename = git_pathdup("BISECT_ANCESTORS_OK");

struct stat st;

int fd;

if (!current_bad_oid)

die("a %s revision is needed", term_bad);

/* Check if file BISECT_ANCESTORS_OK exists. */

if (!stat(filename, &st) && S_ISREG(st.st_mode))

goto done;

/* Bisecting with no good rev is ok. */

if (good_revs.nr == 0)

goto done;

/* Check if all good revs are ancestor of the bad rev. */

if (check_ancestors(prefix))

check_merge_bases(no_checkout);

/* Create file BISECT_ANCESTORS_OK. */

fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);

if (fd < 0)

warning("could not create file '%s': %s",

filename, strerror(errno));

else

close(fd);

done:

free(filename);

}

/*

* This does "git diff-tree --pretty COMMIT" without one fork+exec.

*/

static void show_diff_tree(const char *prefix, struct commit *commit)

{

struct rev_info opt;

/* diff-tree init */

init_revisions(&opt, prefix);

git_config(git_diff_basic_config, NULL); /* no "diff" UI options */

opt.abbrev = 0;

opt.diff = 1;

/* This is what "--pretty" does */

opt.verbose_header = 1;

opt.use_terminator = 0;

opt.commit_format = CMIT_FMT_DEFAULT;

/* diff-tree init */

if (!opt.diffopt.output_format)

opt.diffopt.output_format = DIFF_FORMAT_RAW;

log_tree_commit(&opt, commit);

}

/*

* The terms used for this bisect session are stored in BISECT_TERMS.

* We read them and store them to adapt the messages accordingly.

* Default is bad/good.

*/

void read_bisect_terms(const char **read_bad, const char **read_good)

{

struct strbuf str = STRBUF_INIT;

const char *filename = git_path("BISECT_TERMS");

FILE *fp = fopen(filename, "r");

if (!fp) {

if (errno == ENOENT) {

*read_bad = "bad";

*read_good = "good";

return;

} else {

die("could not read file '%s': %s", filename,

strerror(errno));

}

} else {

strbuf_getline(&str, fp, '\n');

*read_bad = strbuf_detach(&str, NULL);

strbuf_getline(&str, fp, '\n');

*read_good = strbuf_detach(&str, NULL);

}

strbuf_release(&str);

fclose(fp);

}

/*

* We use the convention that exiting with an exit code 10 means that

* the bisection process finished successfully.

* In this case the calling shell script should exit 0.

*

* If no_checkout is non-zero, the bisection process does not

* checkout the trial commit but instead simply updates BISECT_HEAD.

*/

int bisect_next_all(const char *prefix, int no_checkout)

{

struct rev_info revs;

struct commit_list *tried;

int reaches = 0, all = 0, nr, steps;

const unsigned char *bisect_rev;

read_bisect_terms(&term_bad, &term_good);

if (read_bisect_refs())

die("reading bisect refs failed");

check_good_are_ancestors_of_bad(prefix, no_checkout);

bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);

revs.limited = 1;

bisect_common(&revs);

revs.commits = find_bisection(revs.commits, &reaches, &all,

!!skipped_revs.nr);

revs.commits = managed_skipped(revs.commits, &tried);

if (!revs.commits) {

/*

* We should exit here only if the "bad"

* commit is also a "skip" commit.

*/

exit_if_skipped_commits(tried, NULL);

printf("%s was both %s and %s\n",

oid_to_hex(current_bad_oid),

term_good,

term_bad);

exit(1);

}

if (!all) {

fprintf(stderr, "No testable commit found.\n"

"Maybe you started with bad path parameters?\n");

exit(4);

}

bisect_rev = revs.commits->item->object.sha1;

if (!hashcmp(bisect_rev, current_bad_oid->hash)) {

exit_if_skipped_commits(tried, current_bad_oid);

printf("%s is the first %s commit\n", sha1_to_hex(bisect_rev),

term_bad);

show_diff_tree(prefix, revs.commits->item);

/* This means the bisection process succeeded. */

exit(10);

}

nr = all - reaches - 1;

steps = estimate_bisect_steps(all);

printf("Bisecting: %d revision%s left to test after this "

"(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),

steps, (steps == 1 ? "" : "s"));

return bisect_checkout(bisect_rev, no_checkout);

}

static inline int log2i(int n)

{

int log2 = 0;

for (; n > 1; n >>= 1)