Merge branch 'jc/run-receive-hook-cleanup' into maint
[git/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"
12 #include "sha1-array.h"
13
14 static struct sha1_array good_revs;
15 static struct sha1_array skipped_revs;
16
17 static const unsigned char *current_bad_sha1;
18
19 struct argv_array {
20 const char **argv;
21 int argv_nr;
22 int argv_alloc;
23 };
24
25 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
26 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
27 static const char *argv_update_ref[] = {"update-ref", "--no-deref", "BISECT_HEAD", NULL, NULL};
28
29 /* bits #0-15 in revision.h */
30
31 #define COUNTED (1u<<16)
32
33 /*
34 * This is a truly stupid algorithm, but it's only
35 * used for bisection, and we just don't care enough.
36 *
37 * We care just barely enough to avoid recursing for
38 * non-merge entries.
39 */
40 static int count_distance(struct commit_list *entry)
41 {
42 int nr = 0;
43
44 while (entry) {
45 struct commit *commit = entry->item;
46 struct commit_list *p;
47
48 if (commit->object.flags & (UNINTERESTING | COUNTED))
49 break;
50 if (!(commit->object.flags & TREESAME))
51 nr++;
52 commit->object.flags |= COUNTED;
53 p = commit->parents;
54 entry = p;
55 if (p) {
56 p = p->next;
57 while (p) {
58 nr += count_distance(p);
59 p = p->next;
60 }
61 }
62 }
63
64 return nr;
65 }
66
67 static void clear_distance(struct commit_list *list)
68 {
69 while (list) {
70 struct commit *commit = list->item;
71 commit->object.flags &= ~COUNTED;
72 list = list->next;
73 }
74 }
75
76 #define DEBUG_BISECT 0
77
78 static inline int weight(struct commit_list *elem)
79 {
80 return *((int*)(elem->item->util));
81 }
82
83 static inline void weight_set(struct commit_list *elem, int weight)
84 {
85 *((int*)(elem->item->util)) = weight;
86 }
87
88 static int count_interesting_parents(struct commit *commit)
89 {
90 struct commit_list *p;
91 int count;
92
93 for (count = 0, p = commit->parents; p; p = p->next) {
94 if (p->item->object.flags & UNINTERESTING)
95 continue;
96 count++;
97 }
98 return count;
99 }
100
101 static inline int halfway(struct commit_list *p, int nr)
102 {
103 /*
104 * Don't short-cut something we are not going to return!
105 */
106 if (p->item->object.flags & TREESAME)
107 return 0;
108 if (DEBUG_BISECT)
109 return 0;
110 /*
111 * 2 and 3 are halfway of 5.
112 * 3 is halfway of 6 but 2 and 4 are not.
113 */
114 switch (2 * weight(p) - nr) {
115 case -1: case 0: case 1:
116 return 1;
117 default:
118 return 0;
119 }
120 }
121
122 #if !DEBUG_BISECT
123 #define show_list(a,b,c,d) do { ; } while (0)
124 #else
125 static void show_list(const char *debug, int counted, int nr,
126 struct commit_list *list)
127 {
128 struct commit_list *p;
129
130 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
131
132 for (p = list; p; p = p->next) {
133 struct commit_list *pp;
134 struct commit *commit = p->item;
135 unsigned flags = commit->object.flags;
136 enum object_type type;
137 unsigned long size;
138 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
139 const char *subject_start;
140 int subject_len;
141
142 fprintf(stderr, "%c%c%c ",
143 (flags & TREESAME) ? ' ' : 'T',
144 (flags & UNINTERESTING) ? 'U' : ' ',
145 (flags & COUNTED) ? 'C' : ' ');
146 if (commit->util)
147 fprintf(stderr, "%3d", weight(p));
148 else
149 fprintf(stderr, "---");
150 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
151 for (pp = commit->parents; pp; pp = pp->next)
152 fprintf(stderr, " %.*s", 8,
153 sha1_to_hex(pp->item->object.sha1));
154
155 subject_len = find_commit_subject(buf, &subject_start);
156 if (subject_len)
157 fprintf(stderr, " %.*s", subject_len, subject_start);
158 fprintf(stderr, "\n");
159 }
160 }
161 #endif /* DEBUG_BISECT */
162
163 static struct commit_list *best_bisection(struct commit_list *list, int nr)
164 {
165 struct commit_list *p, *best;
166 int best_distance = -1;
167
168 best = list;
169 for (p = list; p; p = p->next) {
170 int distance;
171 unsigned flags = p->item->object.flags;
172
173 if (flags & TREESAME)
174 continue;
175 distance = weight(p);
176 if (nr - distance < distance)
177 distance = nr - distance;
178 if (distance > best_distance) {
179 best = p;
180 best_distance = distance;
181 }
182 }
183
184 return best;
185 }
186
187 struct commit_dist {
188 struct commit *commit;
189 int distance;
190 };
191
192 static int compare_commit_dist(const void *a_, const void *b_)
193 {
194 struct commit_dist *a, *b;
195
196 a = (struct commit_dist *)a_;
197 b = (struct commit_dist *)b_;
198 if (a->distance != b->distance)
199 return b->distance - a->distance; /* desc sort */
200 return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
201 }
202
203 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
204 {
205 struct commit_list *p;
206 struct commit_dist *array = xcalloc(nr, sizeof(*array));
207 int cnt, i;
208
209 for (p = list, cnt = 0; p; p = p->next) {
210 int distance;
211 unsigned flags = p->item->object.flags;
212
213 if (flags & TREESAME)
214 continue;
215 distance = weight(p);
216 if (nr - distance < distance)
217 distance = nr - distance;
218 array[cnt].commit = p->item;
219 array[cnt].distance = distance;
220 cnt++;
221 }
222 qsort(array, cnt, sizeof(*array), compare_commit_dist);
223 for (p = list, i = 0; i < cnt; i++) {
224 struct name_decoration *r = xmalloc(sizeof(*r) + 100);
225 struct object *obj = &(array[i].commit->object);
226
227 sprintf(r->name, "dist=%d", array[i].distance);
228 r->next = add_decoration(&name_decoration, obj, r);
229 p->item = array[i].commit;
230 p = p->next;
231 }
232 if (p)
233 p->next = NULL;
234 free(array);
235 return list;
236 }
237
238 /*
239 * zero or positive weight is the number of interesting commits it can
240 * reach, including itself. Especially, weight = 0 means it does not
241 * reach any tree-changing commits (e.g. just above uninteresting one
242 * but traversal is with pathspec).
243 *
244 * weight = -1 means it has one parent and its distance is yet to
245 * be computed.
246 *
247 * weight = -2 means it has more than one parent and its distance is
248 * unknown. After running count_distance() first, they will get zero
249 * or positive distance.
250 */
251 static struct commit_list *do_find_bisection(struct commit_list *list,
252 int nr, int *weights,
253 int find_all)
254 {
255 int n, counted;
256 struct commit_list *p;
257
258 counted = 0;
259
260 for (n = 0, p = list; p; p = p->next) {
261 struct commit *commit = p->item;
262 unsigned flags = commit->object.flags;
263
264 p->item->util = &weights[n++];
265 switch (count_interesting_parents(commit)) {
266 case 0:
267 if (!(flags & TREESAME)) {
268 weight_set(p, 1);
269 counted++;
270 show_list("bisection 2 count one",
271 counted, nr, list);
272 }
273 /*
274 * otherwise, it is known not to reach any
275 * tree-changing commit and gets weight 0.
276 */
277 break;
278 case 1:
279 weight_set(p, -1);
280 break;
281 default:
282 weight_set(p, -2);
283 break;
284 }
285 }
286
287 show_list("bisection 2 initialize", counted, nr, list);
288
289 /*
290 * If you have only one parent in the resulting set
291 * then you can reach one commit more than that parent
292 * can reach. So we do not have to run the expensive
293 * count_distance() for single strand of pearls.
294 *
295 * However, if you have more than one parents, you cannot
296 * just add their distance and one for yourself, since
297 * they usually reach the same ancestor and you would
298 * end up counting them twice that way.
299 *
300 * So we will first count distance of merges the usual
301 * way, and then fill the blanks using cheaper algorithm.
302 */
303 for (p = list; p; p = p->next) {
304 if (p->item->object.flags & UNINTERESTING)
305 continue;
306 if (weight(p) != -2)
307 continue;
308 weight_set(p, count_distance(p));
309 clear_distance(list);
310
311 /* Does it happen to be at exactly half-way? */
312 if (!find_all && halfway(p, nr))
313 return p;
314 counted++;
315 }
316
317 show_list("bisection 2 count_distance", counted, nr, list);
318
319 while (counted < nr) {
320 for (p = list; p; p = p->next) {
321 struct commit_list *q;
322 unsigned flags = p->item->object.flags;
323
324 if (0 <= weight(p))
325 continue;
326 for (q = p->item->parents; q; q = q->next) {
327 if (q->item->object.flags & UNINTERESTING)
328 continue;
329 if (0 <= weight(q))
330 break;
331 }
332 if (!q)
333 continue;
334
335 /*
336 * weight for p is unknown but q is known.
337 * add one for p itself if p is to be counted,
338 * otherwise inherit it from q directly.
339 */
340 if (!(flags & TREESAME)) {
341 weight_set(p, weight(q)+1);
342 counted++;
343 show_list("bisection 2 count one",
344 counted, nr, list);
345 }
346 else
347 weight_set(p, weight(q));
348
349 /* Does it happen to be at exactly half-way? */
350 if (!find_all && halfway(p, nr))
351 return p;
352 }
353 }
354
355 show_list("bisection 2 counted all", counted, nr, list);
356
357 if (!find_all)
358 return best_bisection(list, nr);
359 else
360 return best_bisection_sorted(list, nr);
361 }
362
363 struct commit_list *find_bisection(struct commit_list *list,
364 int *reaches, int *all,
365 int find_all)
366 {
367 int nr, on_list;
368 struct commit_list *p, *best, *next, *last;
369 int *weights;
370
371 show_list("bisection 2 entry", 0, 0, list);
372
373 /*
374 * Count the number of total and tree-changing items on the
375 * list, while reversing the list.
376 */
377 for (nr = on_list = 0, last = NULL, p = list;
378 p;
379 p = next) {
380 unsigned flags = p->item->object.flags;
381
382 next = p->next;
383 if (flags & UNINTERESTING)
384 continue;
385 p->next = last;
386 last = p;
387 if (!(flags & TREESAME))
388 nr++;
389 on_list++;
390 }
391 list = last;
392 show_list("bisection 2 sorted", 0, nr, list);
393
394 *all = nr;
395 weights = xcalloc(on_list, sizeof(*weights));
396
397 /* Do the real work of finding bisection commit. */
398 best = do_find_bisection(list, nr, weights, find_all);
399 if (best) {
400 if (!find_all)
401 best->next = NULL;
402 *reaches = weight(best);
403 }
404 free(weights);
405 return best;
406 }
407
408 static void argv_array_push(struct argv_array *array, const char *string)
409 {
410 ALLOC_GROW(array->argv, array->argv_nr + 1, array->argv_alloc);
411 array->argv[array->argv_nr++] = string;
412 }
413
414 static void argv_array_push_sha1(struct argv_array *array,
415 const unsigned char *sha1,
416 const char *format)
417 {
418 struct strbuf buf = STRBUF_INIT;
419 strbuf_addf(&buf, format, sha1_to_hex(sha1));
420 argv_array_push(array, strbuf_detach(&buf, NULL));
421 }
422
423 static int register_ref(const char *refname, const unsigned char *sha1,
424 int flags, void *cb_data)
425 {
426 if (!strcmp(refname, "bad")) {
427 current_bad_sha1 = sha1;
428 } else if (!prefixcmp(refname, "good-")) {
429 sha1_array_append(&good_revs, sha1);
430 } else if (!prefixcmp(refname, "skip-")) {
431 sha1_array_append(&skipped_revs, sha1);
432 }
433
434 return 0;
435 }
436
437 static int read_bisect_refs(void)
438 {
439 return for_each_ref_in("refs/bisect/", register_ref, NULL);
440 }
441
442 static void read_bisect_paths(struct argv_array *array)
443 {
444 struct strbuf str = STRBUF_INIT;
445 const char *filename = git_path("BISECT_NAMES");
446 FILE *fp = fopen(filename, "r");
447
448 if (!fp)
449 die_errno("Could not open file '%s'", filename);
450
451 while (strbuf_getline(&str, fp, '\n') != EOF) {
452 char *quoted;
453 int res;
454
455 strbuf_trim(&str);
456 quoted = strbuf_detach(&str, NULL);
457 res = sq_dequote_to_argv(quoted, &array->argv,
458 &array->argv_nr, &array->argv_alloc);
459 if (res)
460 die("Badly quoted content in file '%s': %s",
461 filename, quoted);
462 }
463
464 strbuf_release(&str);
465 fclose(fp);
466 }
467
468 static char *join_sha1_array_hex(struct sha1_array *array, char delim)
469 {
470 struct strbuf joined_hexs = STRBUF_INIT;
471 int i;
472
473 for (i = 0; i < array->nr; i++) {
474 strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
475 if (i + 1 < array->nr)
476 strbuf_addch(&joined_hexs, delim);
477 }
478
479 return strbuf_detach(&joined_hexs, NULL);
480 }
481
482 /*
483 * In this function, passing a not NULL skipped_first is very special.
484 * It means that we want to know if the first commit in the list is
485 * skipped because we will want to test a commit away from it if it is
486 * indeed skipped.
487 * So if the first commit is skipped, we cannot take the shortcut to
488 * just "return list" when we find the first non skipped commit, we
489 * have to return a fully filtered list.
490 *
491 * We use (*skipped_first == -1) to mean "it has been found that the
492 * first commit is not skipped". In this case *skipped_first is set back
493 * to 0 just before the function returns.
494 */
495 struct commit_list *filter_skipped(struct commit_list *list,
496 struct commit_list **tried,
497 int show_all,
498 int *count,
499 int *skipped_first)
500 {
501 struct commit_list *filtered = NULL, **f = &filtered;
502
503 *tried = NULL;
504
505 if (skipped_first)
506 *skipped_first = 0;
507 if (count)
508 *count = 0;
509
510 if (!skipped_revs.nr)
511 return list;
512
513 while (list) {
514 struct commit_list *next = list->next;
515 list->next = NULL;
516 if (0 <= sha1_array_lookup(&skipped_revs,
517 list->item->object.sha1)) {
518 if (skipped_first && !*skipped_first)
519 *skipped_first = 1;
520 /* Move current to tried list */
521 *tried = list;
522 tried = &list->next;
523 } else {
524 if (!show_all) {
525 if (!skipped_first || !*skipped_first)
526 return list;
527 } else if (skipped_first && !*skipped_first) {
528 /* This means we know it's not skipped */
529 *skipped_first = -1;
530 }
531 /* Move current to filtered list */
532 *f = list;
533 f = &list->next;
534 if (count)
535 (*count)++;
536 }
537 list = next;
538 }
539
540 if (skipped_first && *skipped_first == -1)
541 *skipped_first = 0;
542
543 return filtered;
544 }
545
546 #define PRN_MODULO 32768
547
548 /*
549 * This is a pseudo random number generator based on "man 3 rand".
550 * It is not used properly because the seed is the argument and it
551 * is increased by one between each call, but that should not matter
552 * for this application.
553 */
554 static int get_prn(int count) {
555 count = count * 1103515245 + 12345;
556 return ((unsigned)(count/65536) % PRN_MODULO);
557 }
558
559 /*
560 * Custom integer square root from
561 * http://en.wikipedia.org/wiki/Integer_square_root
562 */
563 static int sqrti(int val)
564 {
565 float d, x = val;
566
567 if (val == 0)
568 return 0;
569
570 do {
571 float y = (x + (float)val / x) / 2;
572 d = (y > x) ? y - x : x - y;
573 x = y;
574 } while (d >= 0.5);
575
576 return (int)x;
577 }
578
579 static struct commit_list *skip_away(struct commit_list *list, int count)
580 {
581 struct commit_list *cur, *previous;
582 int prn, index, i;
583
584 prn = get_prn(count);
585 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
586
587 cur = list;
588 previous = NULL;
589
590 for (i = 0; cur; cur = cur->next, i++) {
591 if (i == index) {
592 if (hashcmp(cur->item->object.sha1, current_bad_sha1))
593 return cur;
594 if (previous)
595 return previous;
596 return list;
597 }
598 previous = cur;
599 }
600
601 return list;
602 }
603
604 static struct commit_list *managed_skipped(struct commit_list *list,
605 struct commit_list **tried)
606 {
607 int count, skipped_first;
608
609 *tried = NULL;
610
611 if (!skipped_revs.nr)
612 return list;
613
614 list = filter_skipped(list, tried, 0, &count, &skipped_first);
615
616 if (!skipped_first)
617 return list;
618
619 return skip_away(list, count);
620 }
621
622 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
623 const char *bad_format, const char *good_format,
624 int read_paths)
625 {
626 struct argv_array rev_argv = { NULL, 0, 0 };
627 int i;
628
629 init_revisions(revs, prefix);
630 revs->abbrev = 0;
631 revs->commit_format = CMIT_FMT_UNSPECIFIED;
632
633 /* rev_argv.argv[0] will be ignored by setup_revisions */
634 argv_array_push(&rev_argv, xstrdup("bisect_rev_setup"));
635 argv_array_push_sha1(&rev_argv, current_bad_sha1, bad_format);
636 for (i = 0; i < good_revs.nr; i++)
637 argv_array_push_sha1(&rev_argv, good_revs.sha1[i],
638 good_format);
639 argv_array_push(&rev_argv, xstrdup("--"));
640 if (read_paths)
641 read_bisect_paths(&rev_argv);
642 argv_array_push(&rev_argv, NULL);
643
644 setup_revisions(rev_argv.argv_nr, rev_argv.argv, revs, NULL);
645 }
646
647 static void bisect_common(struct rev_info *revs)
648 {
649 if (prepare_revision_walk(revs))
650 die("revision walk setup failed");
651 if (revs->tree_objects)
652 mark_edges_uninteresting(revs->commits, revs, NULL);
653 }
654
655 static void exit_if_skipped_commits(struct commit_list *tried,
656 const unsigned char *bad)
657 {
658 if (!tried)
659 return;
660
661 printf("There are only 'skip'ped commits left to test.\n"
662 "The first bad commit could be any of:\n");
663 print_commit_list(tried, "%s\n", "%s\n");
664 if (bad)
665 printf("%s\n", sha1_to_hex(bad));
666 printf("We cannot bisect more!\n");
667 exit(2);
668 }
669
670 static int is_expected_rev(const unsigned char *sha1)
671 {
672 const char *filename = git_path("BISECT_EXPECTED_REV");
673 struct stat st;
674 struct strbuf str = STRBUF_INIT;
675 FILE *fp;
676 int res = 0;
677
678 if (stat(filename, &st) || !S_ISREG(st.st_mode))
679 return 0;
680
681 fp = fopen(filename, "r");
682 if (!fp)
683 return 0;
684
685 if (strbuf_getline(&str, fp, '\n') != EOF)
686 res = !strcmp(str.buf, sha1_to_hex(sha1));
687
688 strbuf_release(&str);
689 fclose(fp);
690
691 return res;
692 }
693
694 static void mark_expected_rev(char *bisect_rev_hex)
695 {
696 int len = strlen(bisect_rev_hex);
697 const char *filename = git_path("BISECT_EXPECTED_REV");
698 int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
699
700 if (fd < 0)
701 die_errno("could not create file '%s'", filename);
702
703 bisect_rev_hex[len] = '\n';
704 write_or_die(fd, bisect_rev_hex, len + 1);
705 bisect_rev_hex[len] = '\0';
706
707 if (close(fd) < 0)
708 die("closing file %s: %s", filename, strerror(errno));
709 }
710
711 static int bisect_checkout(char *bisect_rev_hex, int no_checkout)
712 {
713 int res;
714
715 mark_expected_rev(bisect_rev_hex);
716
717 argv_checkout[2] = bisect_rev_hex;
718 if (no_checkout) {
719 argv_update_ref[3] = bisect_rev_hex;
720 if (run_command_v_opt(argv_update_ref, RUN_GIT_CMD))
721 die("update-ref --no-deref HEAD failed on %s",
722 bisect_rev_hex);
723 } else {
724 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
725 if (res)
726 exit(res);
727 }
728
729 argv_show_branch[1] = bisect_rev_hex;
730 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
731 }
732
733 static struct commit *get_commit_reference(const unsigned char *sha1)
734 {
735 struct commit *r = lookup_commit_reference(sha1);
736 if (!r)
737 die("Not a valid commit name %s", sha1_to_hex(sha1));
738 return r;
739 }
740
741 static struct commit **get_bad_and_good_commits(int *rev_nr)
742 {
743 int len = 1 + good_revs.nr;
744 struct commit **rev = xmalloc(len * sizeof(*rev));
745 int i, n = 0;
746
747 rev[n++] = get_commit_reference(current_bad_sha1);
748 for (i = 0; i < good_revs.nr; i++)
749 rev[n++] = get_commit_reference(good_revs.sha1[i]);
750 *rev_nr = n;
751
752 return rev;
753 }
754
755 static void handle_bad_merge_base(void)
756 {
757 if (is_expected_rev(current_bad_sha1)) {
758 char *bad_hex = sha1_to_hex(current_bad_sha1);
759 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
760
761 fprintf(stderr, "The merge base %s is bad.\n"
762 "This means the bug has been fixed "
763 "between %s and [%s].\n",
764 bad_hex, bad_hex, good_hex);
765
766 exit(3);
767 }
768
769 fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
770 "git bisect cannot work properly in this case.\n"
771 "Maybe you mistake good and bad revs?\n");
772 exit(1);
773 }
774
775 static void handle_skipped_merge_base(const unsigned char *mb)
776 {
777 char *mb_hex = sha1_to_hex(mb);
778 char *bad_hex = sha1_to_hex(current_bad_sha1);
779 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
780
781 warning("the merge base between %s and [%s] "
782 "must be skipped.\n"
783 "So we cannot be sure the first bad commit is "
784 "between %s and %s.\n"
785 "We continue anyway.",
786 bad_hex, good_hex, mb_hex, bad_hex);
787 free(good_hex);
788 }
789
790 /*
791 * "check_merge_bases" checks that merge bases are not "bad".
792 *
793 * - If one is "bad", it means the user assumed something wrong
794 * and we must exit with a non 0 error code.
795 * - If one is "good", that's good, we have nothing to do.
796 * - If one is "skipped", we can't know but we should warn.
797 * - If we don't know, we should check it out and ask the user to test.
798 */
799 static void check_merge_bases(int no_checkout)
800 {
801 struct commit_list *result;
802 int rev_nr;
803 struct commit **rev = get_bad_and_good_commits(&rev_nr);
804
805 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
806
807 for (; result; result = result->next) {
808 const unsigned char *mb = result->item->object.sha1;
809 if (!hashcmp(mb, current_bad_sha1)) {
810 handle_bad_merge_base();
811 } else if (0 <= sha1_array_lookup(&good_revs, mb)) {
812 continue;
813 } else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {
814 handle_skipped_merge_base(mb);
815 } else {
816 printf("Bisecting: a merge base must be tested\n");
817 exit(bisect_checkout(sha1_to_hex(mb), no_checkout));
818 }
819 }
820
821 free(rev);
822 free_commit_list(result);
823 }
824
825 static int check_ancestors(const char *prefix)
826 {
827 struct rev_info revs;
828 struct object_array pending_copy;
829 int i, res;
830
831 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
832
833 /* Save pending objects, so they can be cleaned up later. */
834 memset(&pending_copy, 0, sizeof(pending_copy));
835 for (i = 0; i < revs.pending.nr; i++)
836 add_object_array(revs.pending.objects[i].item,
837 revs.pending.objects[i].name,
838 &pending_copy);
839
840 bisect_common(&revs);
841 res = (revs.commits != NULL);
842
843 /* Clean up objects used, as they will be reused. */
844 for (i = 0; i < pending_copy.nr; i++) {
845 struct object *o = pending_copy.objects[i].item;
846 clear_commit_marks((struct commit *)o, ALL_REV_FLAGS);
847 }
848
849 return res;
850 }
851
852 /*
853 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
854 * ancestor of the "bad" rev.
855 *
856 * If that's not the case, we need to check the merge bases.
857 * If a merge base must be tested by the user, its source code will be
858 * checked out to be tested by the user and we will exit.
859 */
860 static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
861 {
862 const char *filename = git_path("BISECT_ANCESTORS_OK");
863 struct stat st;
864 int fd;
865
866 if (!current_bad_sha1)
867 die("a bad revision is needed");
868
869 /* Check if file BISECT_ANCESTORS_OK exists. */
870 if (!stat(filename, &st) && S_ISREG(st.st_mode))
871 return;
872
873 /* Bisecting with no good rev is ok. */
874 if (good_revs.nr == 0)
875 return;
876
877 /* Check if all good revs are ancestor of the bad rev. */
878 if (check_ancestors(prefix))
879 check_merge_bases(no_checkout);
880
881 /* Create file BISECT_ANCESTORS_OK. */
882 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
883 if (fd < 0)
884 warning("could not create file '%s': %s",
885 filename, strerror(errno));
886 else
887 close(fd);
888 }
889
890 /*
891 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
892 */
893 static void show_diff_tree(const char *prefix, struct commit *commit)
894 {
895 struct rev_info opt;
896
897 /* diff-tree init */
898 init_revisions(&opt, prefix);
899 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
900 opt.abbrev = 0;
901 opt.diff = 1;
902
903 /* This is what "--pretty" does */
904 opt.verbose_header = 1;
905 opt.use_terminator = 0;
906 opt.commit_format = CMIT_FMT_DEFAULT;
907
908 /* diff-tree init */
909 if (!opt.diffopt.output_format)
910 opt.diffopt.output_format = DIFF_FORMAT_RAW;
911
912 log_tree_commit(&opt, commit);
913 }
914
915 /*
916 * We use the convention that exiting with an exit code 10 means that
917 * the bisection process finished successfully.
918 * In this case the calling shell script should exit 0.
919 *
920 * If no_checkout is non-zero, the bisection process does not
921 * checkout the trial commit but instead simply updates BISECT_HEAD.
922 */
923 int bisect_next_all(const char *prefix, int no_checkout)
924 {
925 struct rev_info revs;
926 struct commit_list *tried;
927 int reaches = 0, all = 0, nr, steps;
928 const unsigned char *bisect_rev;
929 char bisect_rev_hex[41];
930
931 if (read_bisect_refs())
932 die("reading bisect refs failed");
933
934 check_good_are_ancestors_of_bad(prefix, no_checkout);
935
936 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
937 revs.limited = 1;
938
939 bisect_common(&revs);
940
941 revs.commits = find_bisection(revs.commits, &reaches, &all,
942 !!skipped_revs.nr);
943 revs.commits = managed_skipped(revs.commits, &tried);
944
945 if (!revs.commits) {
946 /*
947 * We should exit here only if the "bad"
948 * commit is also a "skip" commit.
949 */
950 exit_if_skipped_commits(tried, NULL);
951
952 printf("%s was both good and bad\n",
953 sha1_to_hex(current_bad_sha1));
954 exit(1);
955 }
956
957 if (!all) {
958 fprintf(stderr, "No testable commit found.\n"
959 "Maybe you started with bad path parameters?\n");
960 exit(4);
961 }
962
963 bisect_rev = revs.commits->item->object.sha1;
964 memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
965
966 if (!hashcmp(bisect_rev, current_bad_sha1)) {
967 exit_if_skipped_commits(tried, current_bad_sha1);
968 printf("%s is the first bad commit\n", bisect_rev_hex);
969 show_diff_tree(prefix, revs.commits->item);
970 /* This means the bisection process succeeded. */
971 exit(10);
972 }
973
974 nr = all - reaches - 1;
975 steps = estimate_bisect_steps(all);
976 printf("Bisecting: %d revision%s left to test after this "
977 "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
978 steps, (steps == 1 ? "" : "s"));
979
980 return bisect_checkout(bisect_rev_hex, no_checkout);
981 }
982