Code

Merge branch 'ag/maint-apply-too-large-p'
[git.git] / bisect.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "diff.h"
4 #include "revision.h"
5 #include "refs.h"
6 #include "list-objects.h"
7 #include "quote.h"
8 #include "sha1-lookup.h"
9 #include "run-command.h"
10 #include "log-tree.h"
11 #include "bisect.h"
13 struct sha1_array {
14         unsigned char (*sha1)[20];
15         int sha1_nr;
16         int sha1_alloc;
17         int sorted;
18 };
20 static struct sha1_array good_revs;
21 static struct sha1_array skipped_revs;
23 static const unsigned char *current_bad_sha1;
25 struct argv_array {
26         const char **argv;
27         int argv_nr;
28         int argv_alloc;
29 };
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)
38 /*
39  * This is a truly stupid algorithm, but it's only
40  * used for bisection, and we just don't care enough.
41  *
42  * We care just barely enough to avoid recursing for
43  * non-merge entries.
44  */
45 static int count_distance(struct commit_list *entry)
46 {
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;
65                         }
66                 }
67         }
69         return nr;
70 }
72 static void clear_distance(struct commit_list *list)
73 {
74         while (list) {
75                 struct commit *commit = list->item;
76                 commit->object.flags &= ~COUNTED;
77                 list = list->next;
78         }
79 }
81 #define DEBUG_BISECT 0
83 static inline int weight(struct commit_list *elem)
84 {
85         return *((int*)(elem->item->util));
86 }
88 static inline void weight_set(struct commit_list *elem, int weight)
89 {
90         *((int*)(elem->item->util)) = weight;
91 }
93 static int count_interesting_parents(struct commit *commit)
94 {
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++;
102         }
103         return count;
106 static inline int halfway(struct commit_list *p, int nr)
108         /*
109          * Don't short-cut something we are not going to return!
110          */
111         if (p->item->object.flags & TREESAME)
112                 return 0;
113         if (DEBUG_BISECT)
114                 return 0;
115         /*
116          * 2 and 3 are halfway of 5.
117          * 3 is halfway of 6 but 2 and 4 are not.
118          */
119         switch (2 * weight(p) - nr) {
120         case -1: case 0: case 1:
121                 return 1;
122         default:
123                 return 0;
124         }
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++)
163                                 ;
164                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
165                 }
166                 fprintf(stderr, "\n");
167         }
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;
189                 }
190         }
192         return best;
195 struct commit_dist {
196         struct commit *commit;
197         int distance;
198 };
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++;
229         }
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;
239         }
240         if (p)
241                 p->next = NULL;
242         free(array);
243         return list;
246 /*
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).
251  *
252  * weight = -1 means it has one parent and its distance is yet to
253  * be computed.
254  *
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.
258  */
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);
280                         }
281                         /*
282                          * otherwise, it is known not to reach any
283                          * tree-changing commit and gets weight 0.
284                          */
285                         break;
286                 case 1:
287                         weight_set(p, -1);
288                         break;
289                 default:
290                         weight_set(p, -2);
291                         break;
292                 }
293         }
295         show_list("bisection 2 initialize", counted, nr, list);
297         /*
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.
302          *
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.
307          *
308          * So we will first count distance of merges the usual
309          * way, and then fill the blanks using cheaper algorithm.
310          */
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++;
323         }
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;
339                         }
340                         if (!q)
341                                 continue;
343                         /*
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.
347                          */
348                         if (!(flags & TREESAME)) {
349                                 weight_set(p, weight(q)+1);
350                                 counted++;
351                                 show_list("bisection 2 count one",
352                                           counted, nr, list);
353                         }
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;
360                 }
361         }
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);
381         /*
382          * Count the number of total and tree-changing items on the
383          * list, while reversing the list.
384          */
385         for (nr = on_list = 0, last = NULL, p = list;
386              p;
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++;
398         }
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);
411         }
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);
447         }
449         return 0;
452 static int read_bisect_refs(void)
454         return for_each_ref_in("refs/bisect/", register_ref, NULL);
457 static 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_errno("Could not open file '%s'", filename);
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);
477         }
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);
519         }
521         return strbuf_detach(&joined_hexs, NULL);
524 /*
525  * In this function, passing a not NULL skipped_first is very special.
526  * It means that we want to know if the first commit in the list is
527  * skipped because we will want to test a commit away from it if it is
528  * indeed skipped.
529  * So if the first commit is skipped, we cannot take the shortcut to
530  * just "return list" when we find the first non skipped commit, we
531  * have to return a fully filtered list.
532  *
533  * We use (*skipped_first == -1) to mean "it has been found that the
534  * first commit is not skipped". In this case *skipped_first is set back
535  * to 0 just before the function returns.
536  */
537 struct commit_list *filter_skipped(struct commit_list *list,
538                                    struct commit_list **tried,
539                                    int show_all,
540                                    int *count,
541                                    int *skipped_first)
543         struct commit_list *filtered = NULL, **f = &filtered;
545         *tried = NULL;
547         if (skipped_first)
548                 *skipped_first = 0;
549         if (count)
550                 *count = 0;
552         if (!skipped_revs.sha1_nr)
553                 return list;
555         while (list) {
556                 struct commit_list *next = list->next;
557                 list->next = NULL;
558                 if (0 <= lookup_sha1_array(&skipped_revs,
559                                            list->item->object.sha1)) {
560                         if (skipped_first && !*skipped_first)
561                                 *skipped_first = 1;
562                         /* Move current to tried list */
563                         *tried = list;
564                         tried = &list->next;
565                 } else {
566                         if (!show_all) {
567                                 if (!skipped_first || !*skipped_first)
568                                         return list;
569                         } else if (skipped_first && !*skipped_first) {
570                                 /* This means we know it's not skipped */
571                                 *skipped_first = -1;
572                         }
573                         /* Move current to filtered list */
574                         *f = list;
575                         f = &list->next;
576                         if (count)
577                                 (*count)++;
578                 }
579                 list = next;
580         }
582         if (skipped_first && *skipped_first == -1)
583                 *skipped_first = 0;
585         return filtered;
588 #define PRN_MODULO 32768
590 /*
591  * This is a pseudo random number generator based on "man 3 rand".
592  * It is not used properly because the seed is the argument and it
593  * is increased by one between each call, but that should not matter
594  * for this application.
595  */
596 static int get_prn(int count) {
597         count = count * 1103515245 + 12345;
598         return ((unsigned)(count/65536) % PRN_MODULO);
601 /*
602  * Custom integer square root from
603  * http://en.wikipedia.org/wiki/Integer_square_root
604  */
605 static int sqrti(int val)
607         float d, x = val;
609         if (val == 0)
610                 return 0;
612         do {
613                 float y = (x + (float)val / x) / 2;
614                 d = (y > x) ? y - x : x - y;
615                 x = y;
616         } while (d >= 0.5);
618         return (int)x;
621 static struct commit_list *skip_away(struct commit_list *list, int count)
623         struct commit_list *cur, *previous;
624         int prn, index, i;
626         prn = get_prn(count);
627         index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
629         cur = list;
630         previous = NULL;
632         for (i = 0; cur; cur = cur->next, i++) {
633                 if (i == index) {
634                         if (hashcmp(cur->item->object.sha1, current_bad_sha1))
635                                 return cur;
636                         if (previous)
637                                 return previous;
638                         return list;
639                 }
640                 previous = cur;
641         }
643         return list;
646 static struct commit_list *managed_skipped(struct commit_list *list,
647                                            struct commit_list **tried)
649         int count, skipped_first;
651         *tried = NULL;
653         if (!skipped_revs.sha1_nr)
654                 return list;
656         list = filter_skipped(list, tried, 0, &count, &skipped_first);
658         if (!skipped_first)
659                 return list;
661         return skip_away(list, count);
664 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
665                              const char *bad_format, const char *good_format,
666                              int read_paths)
668         struct argv_array rev_argv = { NULL, 0, 0 };
669         int i;
671         init_revisions(revs, prefix);
672         revs->abbrev = 0;
673         revs->commit_format = CMIT_FMT_UNSPECIFIED;
675         /* rev_argv.argv[0] will be ignored by setup_revisions */
676         argv_array_push(&rev_argv, xstrdup("bisect_rev_setup"));
677         argv_array_push_sha1(&rev_argv, current_bad_sha1, bad_format);
678         for (i = 0; i < good_revs.sha1_nr; i++)
679                 argv_array_push_sha1(&rev_argv, good_revs.sha1[i],
680                                      good_format);
681         argv_array_push(&rev_argv, xstrdup("--"));
682         if (read_paths)
683                 read_bisect_paths(&rev_argv);
684         argv_array_push(&rev_argv, NULL);
686         setup_revisions(rev_argv.argv_nr, rev_argv.argv, revs, NULL);
689 static void bisect_common(struct rev_info *revs)
691         if (prepare_revision_walk(revs))
692                 die("revision walk setup failed");
693         if (revs->tree_objects)
694                 mark_edges_uninteresting(revs->commits, revs, NULL);
697 static void exit_if_skipped_commits(struct commit_list *tried,
698                                     const unsigned char *bad)
700         if (!tried)
701                 return;
703         printf("There are only 'skip'ped commits left to test.\n"
704                "The first bad commit could be any of:\n");
705         print_commit_list(tried, "%s\n", "%s\n");
706         if (bad)
707                 printf("%s\n", sha1_to_hex(bad));
708         printf("We cannot bisect more!\n");
709         exit(2);
712 static int is_expected_rev(const unsigned char *sha1)
714         const char *filename = git_path("BISECT_EXPECTED_REV");
715         struct stat st;
716         struct strbuf str = STRBUF_INIT;
717         FILE *fp;
718         int res = 0;
720         if (stat(filename, &st) || !S_ISREG(st.st_mode))
721                 return 0;
723         fp = fopen(filename, "r");
724         if (!fp)
725                 return 0;
727         if (strbuf_getline(&str, fp, '\n') != EOF)
728                 res = !strcmp(str.buf, sha1_to_hex(sha1));
730         strbuf_release(&str);
731         fclose(fp);
733         return res;
736 static void mark_expected_rev(char *bisect_rev_hex)
738         int len = strlen(bisect_rev_hex);
739         const char *filename = git_path("BISECT_EXPECTED_REV");
740         int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
742         if (fd < 0)
743                 die_errno("could not create file '%s'", filename);
745         bisect_rev_hex[len] = '\n';
746         write_or_die(fd, bisect_rev_hex, len + 1);
747         bisect_rev_hex[len] = '\0';
749         if (close(fd) < 0)
750                 die("closing file %s: %s", filename, strerror(errno));
753 static int bisect_checkout(char *bisect_rev_hex)
755         int res;
757         mark_expected_rev(bisect_rev_hex);
759         argv_checkout[2] = bisect_rev_hex;
760         res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
761         if (res)
762                 exit(res);
764         argv_show_branch[1] = bisect_rev_hex;
765         return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
768 static struct commit *get_commit_reference(const unsigned char *sha1)
770         struct commit *r = lookup_commit_reference(sha1);
771         if (!r)
772                 die("Not a valid commit name %s", sha1_to_hex(sha1));
773         return r;
776 static struct commit **get_bad_and_good_commits(int *rev_nr)
778         int len = 1 + good_revs.sha1_nr;
779         struct commit **rev = xmalloc(len * sizeof(*rev));
780         int i, n = 0;
782         rev[n++] = get_commit_reference(current_bad_sha1);
783         for (i = 0; i < good_revs.sha1_nr; i++)
784                 rev[n++] = get_commit_reference(good_revs.sha1[i]);
785         *rev_nr = n;
787         return rev;
790 static void handle_bad_merge_base(void)
792         if (is_expected_rev(current_bad_sha1)) {
793                 char *bad_hex = sha1_to_hex(current_bad_sha1);
794                 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
796                 fprintf(stderr, "The merge base %s is bad.\n"
797                         "This means the bug has been fixed "
798                         "between %s and [%s].\n",
799                         bad_hex, bad_hex, good_hex);
801                 exit(3);
802         }
804         fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
805                 "git bisect cannot work properly in this case.\n"
806                 "Maybe you mistake good and bad revs?\n");
807         exit(1);
810 static void handle_skipped_merge_base(const unsigned char *mb)
812         char *mb_hex = sha1_to_hex(mb);
813         char *bad_hex = sha1_to_hex(current_bad_sha1);
814         char *good_hex = join_sha1_array_hex(&good_revs, ' ');
816         warning("the merge base between %s and [%s] "
817                 "must be skipped.\n"
818                 "So we cannot be sure the first bad commit is "
819                 "between %s and %s.\n"
820                 "We continue anyway.",
821                 bad_hex, good_hex, mb_hex, bad_hex);
822         free(good_hex);
825 /*
826  * "check_merge_bases" checks that merge bases are not "bad".
827  *
828  * - If one is "bad", it means the user assumed something wrong
829  * and we must exit with a non 0 error code.
830  * - If one is "good", that's good, we have nothing to do.
831  * - If one is "skipped", we can't know but we should warn.
832  * - If we don't know, we should check it out and ask the user to test.
833  */
834 static void check_merge_bases(void)
836         struct commit_list *result;
837         int rev_nr;
838         struct commit **rev = get_bad_and_good_commits(&rev_nr);
840         result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
842         for (; result; result = result->next) {
843                 const unsigned char *mb = result->item->object.sha1;
844                 if (!hashcmp(mb, current_bad_sha1)) {
845                         handle_bad_merge_base();
846                 } else if (0 <= lookup_sha1_array(&good_revs, mb)) {
847                         continue;
848                 } else if (0 <= lookup_sha1_array(&skipped_revs, mb)) {
849                         handle_skipped_merge_base(mb);
850                 } else {
851                         printf("Bisecting: a merge base must be tested\n");
852                         exit(bisect_checkout(sha1_to_hex(mb)));
853                 }
854         }
856         free(rev);
857         free_commit_list(result);
860 static int check_ancestors(const char *prefix)
862         struct rev_info revs;
863         struct object_array pending_copy;
864         int i, res;
866         bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
868         /* Save pending objects, so they can be cleaned up later. */
869         memset(&pending_copy, 0, sizeof(pending_copy));
870         for (i = 0; i < revs.pending.nr; i++)
871                 add_object_array(revs.pending.objects[i].item,
872                                  revs.pending.objects[i].name,
873                                  &pending_copy);
875         bisect_common(&revs);
876         res = (revs.commits != NULL);
878         /* Clean up objects used, as they will be reused. */
879         for (i = 0; i < pending_copy.nr; i++) {
880                 struct object *o = pending_copy.objects[i].item;
881                 clear_commit_marks((struct commit *)o, ALL_REV_FLAGS);
882         }
884         return res;
887 /*
888  * "check_good_are_ancestors_of_bad" checks that all "good" revs are
889  * ancestor of the "bad" rev.
890  *
891  * If that's not the case, we need to check the merge bases.
892  * If a merge base must be tested by the user, its source code will be
893  * checked out to be tested by the user and we will exit.
894  */
895 static void check_good_are_ancestors_of_bad(const char *prefix)
897         const char *filename = git_path("BISECT_ANCESTORS_OK");
898         struct stat st;
899         int fd;
901         if (!current_bad_sha1)
902                 die("a bad revision is needed");
904         /* Check if file BISECT_ANCESTORS_OK exists. */
905         if (!stat(filename, &st) && S_ISREG(st.st_mode))
906                 return;
908         /* Bisecting with no good rev is ok. */
909         if (good_revs.sha1_nr == 0)
910                 return;
912         /* Check if all good revs are ancestor of the bad rev. */
913         if (check_ancestors(prefix))
914                 check_merge_bases();
916         /* Create file BISECT_ANCESTORS_OK. */
917         fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
918         if (fd < 0)
919                 warning("could not create file '%s': %s",
920                         filename, strerror(errno));
921         else
922                 close(fd);
925 /*
926  * This does "git diff-tree --pretty COMMIT" without one fork+exec.
927  */
928 static void show_diff_tree(const char *prefix, struct commit *commit)
930         struct rev_info opt;
932         /* diff-tree init */
933         init_revisions(&opt, prefix);
934         git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
935         opt.abbrev = 0;
936         opt.diff = 1;
938         /* This is what "--pretty" does */
939         opt.verbose_header = 1;
940         opt.use_terminator = 0;
941         opt.commit_format = CMIT_FMT_DEFAULT;
943         /* diff-tree init */
944         if (!opt.diffopt.output_format)
945                 opt.diffopt.output_format = DIFF_FORMAT_RAW;
947         log_tree_commit(&opt, commit);
950 /*
951  * We use the convention that exiting with an exit code 10 means that
952  * the bisection process finished successfully.
953  * In this case the calling shell script should exit 0.
954  */
955 int bisect_next_all(const char *prefix)
957         struct rev_info revs;
958         struct commit_list *tried;
959         int reaches = 0, all = 0, nr, steps;
960         const unsigned char *bisect_rev;
961         char bisect_rev_hex[41];
963         if (read_bisect_refs())
964                 die("reading bisect refs failed");
966         check_good_are_ancestors_of_bad(prefix);
968         bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
969         revs.limited = 1;
971         bisect_common(&revs);
973         revs.commits = find_bisection(revs.commits, &reaches, &all,
974                                        !!skipped_revs.sha1_nr);
975         revs.commits = managed_skipped(revs.commits, &tried);
977         if (!revs.commits) {
978                 /*
979                  * We should exit here only if the "bad"
980                  * commit is also a "skip" commit.
981                  */
982                 exit_if_skipped_commits(tried, NULL);
984                 printf("%s was both good and bad\n",
985                        sha1_to_hex(current_bad_sha1));
986                 exit(1);
987         }
989         bisect_rev = revs.commits->item->object.sha1;
990         memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
992         if (!hashcmp(bisect_rev, current_bad_sha1)) {
993                 exit_if_skipped_commits(tried, current_bad_sha1);
994                 printf("%s is the first bad commit\n", bisect_rev_hex);
995                 show_diff_tree(prefix, revs.commits->item);
996                 /* This means the bisection process succeeded. */
997                 exit(10);
998         }
1000         nr = all - reaches - 1;
1001         steps = estimate_bisect_steps(all);
1002         printf("Bisecting: %d revision%s left to test after this "
1003                "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
1004                steps, (steps == 1 ? "" : "s"));
1006         return bisect_checkout(bisect_rev_hex);