diff options
Diffstat (limited to 'third_party/git/bisect.c')
| -rw-r--r-- | third_party/git/bisect.c | 1145 |
1 files changed, 1145 insertions, 0 deletions
diff --git a/third_party/git/bisect.c b/third_party/git/bisect.c new file mode 100644 index 000000000000..9154f810f76a --- /dev/null +++ b/third_party/git/bisect.c @@ -0,0 +1,1145 @@ +#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 "sha1-lookup.h" +#include "run-command.h" +#include "log-tree.h" +#include "bisect.h" +#include "sha1-array.h" +#include "argv-array.h" +#include "commit-slab.h" +#include "commit-reach.h" +#include "object-store.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 *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_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) +{ + 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; + } +} + +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 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 ", + (flags & TREESAME) ? ' ' : 'T', + (flags & UNINTERESTING) ? 'U' : ' ', + (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 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 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 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, 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, + 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; + + *commit_weight_at(&commit_weight, p->item) = &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); +} + +void find_bisection(struct commit_list **commit_list, int *reaches, + int *all, int find_all) +{ + 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 flags = p->item->object.flags; + + next = p->next; + if (flags & UNINTERESTING) { + free(p); + 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) { + 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_head_name, "head-name") + +static void read_bisect_paths(struct argv_array *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_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 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 argv_array rev_argv = ARGV_ARRAY_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 */ + 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, + oid_to_hex(good_revs.oid + 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, 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; +} + +static enum bisect_error bisect_checkout(const struct object_id *bisect_rev, int no_checkout) +{ + char bisect_rev_hex[GIT_MAX_HEXSZ + 1]; + enum bisect_error res = BISECT_OK; + + memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), the_hash_algo->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 { + res = run_command_v_opt(argv_checkout, RUN_GIT_CMD); + if (res) + /* + * 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_FAILURE (-1). + */ + return -abs(res); + } + + argv_show_branch[1] = bisect_rev_hex; + res = run_command_v_opt(argv_show_branch, 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_FAILURE (-1). + */ + return -abs(res); +} + +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_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); + } + 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_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 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. + * If no_checkout is non-zero, the bisection process does not + * checkout the trial commit but instead simply updates BISECT_HEAD. + */ +enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int no_checkout) +{ + 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; + + read_bisect_terms(&term_bad, &term_good); + if (read_bisect_refs()) + die(_("reading bisect refs failed")); + + 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.limited = 1; + + bisect_common(&revs); + + find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr); + 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 parameters?\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); + + 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()); + /* 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; +} |