git/bisect.c
René Scharfe 48af1fdee3 bisect--helper: double-check run command on exit code 126 and 127
When a run command cannot be executed or found, shells return exit code
126 or 127, respectively.  Valid run commands are allowed to return
these codes as well to indicate bad revisions, though, for historical
reasons.  This means typos can cause bogus bisect runs that go over the
full distance and end up reporting invalid results.

The best solution would be to reserve exit codes 126 and 127, like
71b0251cdd (Bisect run: "skip" current commit if script exit code is
125., 2007-10-26) did for 125, and abort bisect run when we get them.
That might be inconvenient for those who relied on the documentation
stating that 126 and 127 can be used for bad revisions, though.

The workaround used by this patch is to run the command on a known-good
revision and abort if we still get the same error code.  This adds one
step to runs with scripts that use exit codes 126 and 127, but keeps
them supported, with one exception: It won't work with commands that
cannot recognize the (manually marked) known-good revision as such.

Run commands that use low exit codes are unaffected.  Typos are reported
after executing the missing command twice and three checkouts (the first
step, the known good revision and back to the revision of the first
step).

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-19 09:35:03 -08:00

1185 lines
30 KiB
C

#include "cache.h"
#include "config.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "refs.h"
#include "list-objects.h"
#include "quote.h"
#include "hash-lookup.h"
#include "run-command.h"
#include "log-tree.h"
#include "bisect.h"
#include "oid-array.h"
#include "strvec.h"
#include "commit-slab.h"
#include "commit-reach.h"
#include "object-store.h"
#include "dir.h"
static struct oid_array good_revs;
static struct oid_array skipped_revs;
static struct object_id *current_bad_oid;
static const char *argv_checkout[] = {"checkout", "-q", 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_commit_slab(commit_weight, int *);
static struct commit_weight commit_weight;
#define DEBUG_BISECT 0
static inline int weight(struct commit_list *elem)
{
return **commit_weight_at(&commit_weight, elem->item);
}
static inline void weight_set(struct commit_list *elem, int weight)
{
**commit_weight_at(&commit_weight, elem->item) = weight;
}
static int count_interesting_parents(struct commit *commit, unsigned bisect_flags)
{
struct commit_list *p;
int count;
for (count = 0, p = commit->parents; p; p = p->next) {
if (!(p->item->object.flags & UNINTERESTING))
count++;
if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
break;
}
return count;
}
static inline int approx_halfway(struct commit_list *p, int nr)
{
int diff;
/*
* Don't short-cut something we are not going to return!
*/
if (p->item->object.flags & TREESAME)
return 0;
if (DEBUG_BISECT)
return 0;
/*
* For small number of commits 2 and 3 are halfway of 5, and
* 3 is halfway of 6 but 2 and 4 are not.
*/
diff = 2 * weight(p) - nr;
switch (diff) {
case -1: case 0: case 1:
return 1;
default:
/*
* For large number of commits we are not so strict, it's
* good enough if it's within ~0.1% of the halfway point,
* e.g. 5000 is exactly halfway of 10000, but we consider
* the values [4996, 5004] as halfway as well.
*/
if (abs(diff) < nr / 1024)
return 1;
return 0;
}
}
static void show_list(const char *debug, int counted, int nr,
struct commit_list *list)
{
struct commit_list *p;
if (!DEBUG_BISECT)
return;
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 commit_flags = commit->object.flags;
enum object_type type;
unsigned long size;
char *buf = read_object_file(&commit->object.oid, &type,
&size);
const char *subject_start;
int subject_len;
fprintf(stderr, "%c%c%c ",
(commit_flags & TREESAME) ? ' ' : 'T',
(commit_flags & UNINTERESTING) ? 'U' : ' ',
(commit_flags & COUNTED) ? 'C' : ' ');
if (*commit_weight_at(&commit_weight, p->item))
fprintf(stderr, "%3d", weight(p));
else
fprintf(stderr, "---");
fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
for (pp = commit->parents; pp; pp = pp->next)
fprintf(stderr, " %.*s", 8,
oid_to_hex(&pp->item->object.oid));
subject_len = find_commit_subject(buf, &subject_start);
if (subject_len)
fprintf(stderr, " %.*s", subject_len, subject_start);
fprintf(stderr, "\n");
}
}
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 commit_flags = p->item->object.flags;
if (commit_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 oidcmp(&a->commit->object.oid, &b->commit->object.oid);
}
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));
struct strbuf buf = STRBUF_INIT;
int cnt, i;
for (p = list, cnt = 0; p; p = p->next) {
int distance;
unsigned commit_flags = p->item->object.flags;
if (commit_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, compare_commit_dist);
for (p = list, i = 0; i < cnt; i++) {
struct object *obj = &(array[i].commit->object);
strbuf_reset(&buf);
strbuf_addf(&buf, "dist=%d", array[i].distance);
add_name_decoration(DECORATION_NONE, buf.buf, obj);
p->item = array[i].commit;
if (i < cnt - 1)
p = p->next;
}
if (p) {
free_commit_list(p->next);
p->next = NULL;
}
strbuf_release(&buf);
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,
unsigned bisect_flags)
{
int n, counted;
struct commit_list *p;
counted = 0;
for (n = 0, p = list; p; p = p->next) {
struct commit *commit = p->item;
unsigned commit_flags = commit->object.flags;
*commit_weight_at(&commit_weight, p->item) = &weights[n++];
switch (count_interesting_parents(commit, bisect_flags)) {
case 0:
if (!(commit_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;
if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
BUG("shouldn't be calling count-distance in fp mode");
weight_set(p, count_distance(p));
clear_distance(list);
/* Does it happen to be at half-way? */
if (!(bisect_flags & FIND_BISECTION_ALL) &&
approx_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 commit_flags = p->item->object.flags;
if (0 <= weight(p))
continue;
for (q = p->item->parents;
q;
q = bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY ? NULL : 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 (!(commit_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 half-way? */
if (!(bisect_flags & FIND_BISECTION_ALL) &&
approx_halfway(p, nr))
return p;
}
}
show_list("bisection 2 counted all", counted, nr, list);
if (!(bisect_flags & FIND_BISECTION_ALL))
return best_bisection(list, nr);
else
return best_bisection_sorted(list, nr);
}
void find_bisection(struct commit_list **commit_list, int *reaches,
int *all, unsigned bisect_flags)
{
int nr, on_list;
struct commit_list *list, *p, *best, *next, *last;
int *weights;
show_list("bisection 2 entry", 0, 0, *commit_list);
init_commit_weight(&commit_weight);
/*
* Count the number of total and tree-changing items on the
* list, while reversing the list.
*/
for (nr = on_list = 0, last = NULL, p = *commit_list;
p;
p = next) {
unsigned commit_flags = p->item->object.flags;
next = p->next;
if (commit_flags & UNINTERESTING) {
free(p);
continue;
}
p->next = last;
last = p;
if (!(commit_flags & TREESAME))
nr++;
on_list++;
}
list = last;
show_list("bisection 2 sorted", 0, nr, list);
*all = nr;
CALLOC_ARRAY(weights, on_list);
/* Do the real work of finding bisection commit. */
best = do_find_bisection(list, nr, weights, bisect_flags);
if (best) {
if (!(bisect_flags & FIND_BISECTION_ALL)) {
list->item = best->item;
free_commit_list(list->next);
best = list;
best->next = NULL;
}
*reaches = weight(best);
}
free(weights);
*commit_list = best;
clear_commit_weight(&commit_weight);
}
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)) {
oid_array_append(&good_revs, oid);
} else if (starts_with(refname, "skip-")) {
oid_array_append(&skipped_revs, oid);
}
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 GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
static GIT_PATH_FUNC(git_path_head_name, "head-name")
static void read_bisect_paths(struct strvec *array)
{
struct strbuf str = STRBUF_INIT;
const char *filename = git_path_bisect_names();
FILE *fp = xfopen(filename, "r");
while (strbuf_getline_lf(&str, fp) != EOF) {
strbuf_trim(&str);
if (sq_dequote_to_strvec(str.buf, array))
die(_("Badly quoted content in file '%s': %s"),
filename, str.buf);
}
strbuf_release(&str);
fclose(fp);
}
static char *join_oid_array_hex(struct oid_array *array, char delim)
{
struct strbuf joined_hexs = STRBUF_INIT;
int i;
for (i = 0; i < array->nr; i++) {
strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + 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,
struct commit_list **tried,
int show_all,
int *count,
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 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
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
* https://en.wikipedia.org/wiki/Integer_square_root
*/
static int sqrti(int val)
{
float d, x = val;
if (!val)
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 (!oideq(&cur->item->object.oid, current_bad_oid))
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 repository *r, struct rev_info *revs,
const char *prefix,
const char *bad_format, const char *good_format,
int read_paths)
{
struct strvec rev_argv = STRVEC_INIT;
int i;
repo_init_revisions(r, revs, prefix);
revs->abbrev = 0;
revs->commit_format = CMIT_FMT_UNSPECIFIED;
/* rev_argv.argv[0] will be ignored by setup_revisions */
strvec_push(&rev_argv, "bisect_rev_setup");
strvec_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
for (i = 0; i < good_revs.nr; i++)
strvec_pushf(&rev_argv, good_format,
oid_to_hex(good_revs.oid + i));
strvec_push(&rev_argv, "--");
if (read_paths)
read_bisect_paths(&rev_argv);
setup_revisions(rev_argv.nr, rev_argv.v, 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, 0);
}
static enum bisect_error error_if_skipped_commits(struct commit_list *tried,
const struct object_id *bad)
{
if (!tried)
return BISECT_OK;
printf("There are only 'skip'ped commits left to test.\n"
"The first %s commit could be any of:\n", term_bad);
for ( ; tried; tried = tried->next)
printf("%s\n", oid_to_hex(&tried->item->object.oid));
if (bad)
printf("%s\n", oid_to_hex(bad));
printf(_("We cannot bisect more!\n"));
return BISECT_ONLY_SKIPPED_LEFT;
}
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_or_warn(filename, "r");
if (!fp)
return 0;
if (strbuf_getline_lf(&str, fp) != EOF)
res = !strcmp(str.buf, oid_to_hex(oid));
strbuf_release(&str);
fclose(fp);
return res;
}
enum bisect_error bisect_checkout(const struct object_id *bisect_rev,
int no_checkout)
{
char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
struct commit *commit;
struct pretty_print_context pp = {0};
struct strbuf commit_msg = STRBUF_INIT;
oid_to_hex_r(bisect_rev_hex, bisect_rev);
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 {
if (run_command_v_opt(argv_checkout, RUN_GIT_CMD))
/*
* Errors in `run_command()` itself, signaled by res < 0,
* and errors in the child process, signaled by res > 0
* can both be treated as regular BISECT_FAILED (-1).
*/
return BISECT_FAILED;
}
commit = lookup_commit_reference(the_repository, bisect_rev);
format_commit_message(commit, "[%H] %s%n", &commit_msg, &pp);
fputs(commit_msg.buf, stdout);
strbuf_release(&commit_msg);
return BISECT_OK;
}
static struct commit *get_commit_reference(struct repository *r,
const struct object_id *oid)
{
struct commit *c = lookup_commit_reference(r, oid);
if (!c)
die(_("Not a valid commit name %s"), oid_to_hex(oid));
return c;
}
static struct commit **get_bad_and_good_commits(struct repository *r,
int *rev_nr)
{
struct commit **rev;
int i, n = 0;
ALLOC_ARRAY(rev, 1 + good_revs.nr);
rev[n++] = get_commit_reference(r, current_bad_oid);
for (i = 0; i < good_revs.nr; i++)
rev[n++] = get_commit_reference(r, good_revs.oid + i);
*rev_nr = n;
return rev;
}
static enum bisect_error 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_oid_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);
}
return BISECT_MERGE_BASE_CHECK;
}
fprintf(stderr, _("Some %s revs are not ancestors 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);
return BISECT_FAILED;
}
static void handle_skipped_merge_base(const struct object_id *mb)
{
char *mb_hex = oid_to_hex(mb);
char *bad_hex = oid_to_hex(current_bad_oid);
char *good_hex = join_oid_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 return error 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.
* - If a merge base must be tested, on success return
* BISECT_INTERNAL_SUCCESS_MERGE_BASE (-11) a special condition
* for early success, this will be converted back to 0 in
* check_good_are_ancestors_of_bad().
*/
static enum bisect_error check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
{
enum bisect_error res = BISECT_OK;
struct commit_list *result;
result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
for (; result; result = result->next) {
const struct object_id *mb = &result->item->object.oid;
if (oideq(mb, current_bad_oid)) {
res = handle_bad_merge_base();
break;
} else if (0 <= oid_array_lookup(&good_revs, mb)) {
continue;
} else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
handle_skipped_merge_base(mb);
} else {
printf(_("Bisecting: a merge base must be tested\n"));
res = bisect_checkout(mb, no_checkout);
if (!res)
/* indicate early success */
res = BISECT_INTERNAL_SUCCESS_MERGE_BASE;
break;
}
}
free_commit_list(result);
return res;
}
static int check_ancestors(struct repository *r, int rev_nr,
struct commit **rev, const char *prefix)
{
struct rev_info revs;
int res;
bisect_rev_setup(r, &revs, prefix, "^%s", "%s", 0);
bisect_common(&revs);
res = (revs.commits != NULL);
/* Clean up objects used, as they will be reused. */
clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
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 return.
*/
static enum bisect_error check_good_are_ancestors_of_bad(struct repository *r,
const char *prefix,
int no_checkout)
{
char *filename;
struct stat st;
int fd, rev_nr;
enum bisect_error res = BISECT_OK;
struct commit **rev;
if (!current_bad_oid)
return error(_("a %s revision is needed"), term_bad);
filename = git_pathdup("BISECT_ANCESTORS_OK");
/* 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)
goto done;
/* Check if all good revs are ancestor of the bad rev. */
rev = get_bad_and_good_commits(r, &rev_nr);
if (check_ancestors(r, rev_nr, rev, prefix))
res = check_merge_bases(rev_nr, rev, no_checkout);
free(rev);
if (!res) {
/* Create file BISECT_ANCESTORS_OK. */
fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
if (fd < 0)
/*
* BISECT_ANCESTORS_OK file is not absolutely necessary,
* the bisection process will continue at the next
* bisection step.
* So, just signal with a warning that something
* might be wrong.
*/
warning_errno(_("could not create file '%s'"),
filename);
else
close(fd);
}
done:
free(filename);
return res;
}
/*
* This does "git diff-tree --pretty COMMIT" without one fork+exec.
*/
static void show_diff_tree(struct repository *r,
const char *prefix,
struct commit *commit)
{
const char *argv[] = {
"diff-tree", "--pretty", "--stat", "--summary", "--cc", NULL
};
struct rev_info opt;
git_config(git_diff_ui_config, NULL);
repo_init_revisions(r, &opt, prefix);
setup_revisions(ARRAY_SIZE(argv) - 1, argv, &opt, NULL);
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_errno(_("could not read file '%s'"), filename);
}
} else {
strbuf_getline_lf(&str, fp);
*read_bad = strbuf_detach(&str, NULL);
strbuf_getline_lf(&str, fp);
*read_good = strbuf_detach(&str, NULL);
}
strbuf_release(&str);
fclose(fp);
}
/*
* We use the convention that return BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10) means
* the bisection process finished successfully.
* In this case the calling function or command should not turn a
* BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND return code into an error or a non zero exit code.
*
* Checking BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND
* in bisect_helper::bisect_next() and only transforming it to 0 at
* the end of bisect_helper::cmd_bisect__helper() helps bypassing
* all the code related to finding a commit to test.
*/
enum bisect_error bisect_next_all(struct repository *r, const char *prefix)
{
struct rev_info revs;
struct commit_list *tried;
int reaches = 0, all = 0, nr, steps;
enum bisect_error res = BISECT_OK;
struct object_id *bisect_rev;
char *steps_msg;
/*
* If no_checkout is non-zero, the bisection process does not
* checkout the trial commit but instead simply updates BISECT_HEAD.
*/
int no_checkout = ref_exists("BISECT_HEAD");
unsigned bisect_flags = 0;
read_bisect_terms(&term_bad, &term_good);
if (read_bisect_refs())
die(_("reading bisect refs failed"));
if (file_exists(git_path_bisect_first_parent()))
bisect_flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
if (skipped_revs.nr)
bisect_flags |= FIND_BISECTION_ALL;
res = check_good_are_ancestors_of_bad(r, prefix, no_checkout);
if (res)
return res;
bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
revs.first_parent_only = !!(bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY);
revs.limited = 1;
bisect_common(&revs);
find_bisection(&revs.commits, &reaches, &all, bisect_flags);
revs.commits = managed_skipped(revs.commits, &tried);
if (!revs.commits) {
/*
* We should return error here only if the "bad"
* commit is also a "skip" commit.
*/
res = error_if_skipped_commits(tried, NULL);
if (res < 0)
return res;
printf(_("%s was both %s and %s\n"),
oid_to_hex(current_bad_oid),
term_good,
term_bad);
return BISECT_FAILED;
}
if (!all) {
fprintf(stderr, _("No testable commit found.\n"
"Maybe you started with bad path arguments?\n"));
return BISECT_NO_TESTABLE_COMMIT;
}
bisect_rev = &revs.commits->item->object.oid;
if (oideq(bisect_rev, current_bad_oid)) {
res = error_if_skipped_commits(tried, current_bad_oid);
if (res)
return res;
printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
term_bad);
show_diff_tree(r, prefix, revs.commits->item);
/*
* This means the bisection process succeeded.
* Using BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10)
* so that the call chain can simply check
* for negative return values for early returns up
* until the cmd_bisect__helper() caller.
*/
return BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
}
nr = all - reaches - 1;
steps = estimate_bisect_steps(all);
steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
steps), steps);
/*
* TRANSLATORS: the last %s will be replaced with "(roughly %d
* steps)" translation.
*/
printf(Q_("Bisecting: %d revision left to test after this %s\n",
"Bisecting: %d revisions left to test after this %s\n",
nr), nr, steps_msg);
free(steps_msg);
/* Clean up objects used, as they will be reused. */
repo_clear_commit_marks(r, ALL_REV_FLAGS);
return bisect_checkout(bisect_rev, no_checkout);
}
static inline int log2i(int n)
{
int log2 = 0;
for (; n > 1; n >>= 1)
log2++;
return log2;
}
static inline int exp2i(int n)
{
return 1 << n;
}
/*
* Estimate the number of bisect steps left (after the current step)
*
* For any x between 0 included and 2^n excluded, the probability for
* n - 1 steps left looks like:
*
* P(2^n + x) == (2^n - x) / (2^n + x)
*
* and P(2^n + x) < 0.5 means 2^n < 3x
*/
int estimate_bisect_steps(int all)
{
int n, x, e;
if (all < 3)
return 0;
n = log2i(all);
e = exp2i(n);
x = all - e;
return (e < 3 * x) ? n : n - 1;
}
static int mark_for_removal(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
struct string_list *refs = cb_data;
char *ref = xstrfmt("refs/bisect%s", refname);
string_list_append(refs, ref);
return 0;
}
int bisect_clean_state(void)
{
int result = 0;
/* There may be some refs packed during bisection */
struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
result = delete_refs("bisect: remove", &refs_for_removal, REF_NO_DEREF);
refs_for_removal.strdup_strings = 1;
string_list_clear(&refs_for_removal, 0);
unlink_or_warn(git_path_bisect_expected_rev());
unlink_or_warn(git_path_bisect_ancestors_ok());
unlink_or_warn(git_path_bisect_log());
unlink_or_warn(git_path_bisect_names());
unlink_or_warn(git_path_bisect_run());
unlink_or_warn(git_path_bisect_terms());
unlink_or_warn(git_path_bisect_first_parent());
/* Cleanup head-name if it got left by an old version of git-bisect */
unlink_or_warn(git_path_head_name());
/*
* Cleanup BISECT_START last to support the --no-checkout option
* introduced in the commit 4796e823a.
*/
unlink_or_warn(git_path_bisect_start());
return result;
}