Merge branch 'ma/bisect-leakfix'
[git/git.git] / bisect.c
1 #include "cache.h"
2 #include "config.h"
3 #include "commit.h"
4 #include "diff.h"
5 #include "revision.h"
6 #include "refs.h"
7 #include "list-objects.h"
8 #include "quote.h"
9 #include "sha1-lookup.h"
10 #include "run-command.h"
11 #include "log-tree.h"
12 #include "bisect.h"
13 #include "sha1-array.h"
14 #include "argv-array.h"
15
16 static struct oid_array good_revs;
17 static struct oid_array skipped_revs;
18
19 static struct object_id *current_bad_oid;
20
21 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
22 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
23
24 static const char *term_bad;
25 static const char *term_good;
26
27 /* Remember to update object flag allocation in object.h */
28 #define COUNTED (1u<<16)
29
30 /*
31 * This is a truly stupid algorithm, but it's only
32 * used for bisection, and we just don't care enough.
33 *
34 * We care just barely enough to avoid recursing for
35 * non-merge entries.
36 */
37 static int count_distance(struct commit_list *entry)
38 {
39 int nr = 0;
40
41 while (entry) {
42 struct commit *commit = entry->item;
43 struct commit_list *p;
44
45 if (commit->object.flags & (UNINTERESTING | COUNTED))
46 break;
47 if (!(commit->object.flags & TREESAME))
48 nr++;
49 commit->object.flags |= COUNTED;
50 p = commit->parents;
51 entry = p;
52 if (p) {
53 p = p->next;
54 while (p) {
55 nr += count_distance(p);
56 p = p->next;
57 }
58 }
59 }
60
61 return nr;
62 }
63
64 static void clear_distance(struct commit_list *list)
65 {
66 while (list) {
67 struct commit *commit = list->item;
68 commit->object.flags &= ~COUNTED;
69 list = list->next;
70 }
71 }
72
73 #define DEBUG_BISECT 0
74
75 static inline int weight(struct commit_list *elem)
76 {
77 return *((int*)(elem->item->util));
78 }
79
80 static inline void weight_set(struct commit_list *elem, int weight)
81 {
82 *((int*)(elem->item->util)) = weight;
83 }
84
85 static int count_interesting_parents(struct commit *commit)
86 {
87 struct commit_list *p;
88 int count;
89
90 for (count = 0, p = commit->parents; p; p = p->next) {
91 if (p->item->object.flags & UNINTERESTING)
92 continue;
93 count++;
94 }
95 return count;
96 }
97
98 static inline int halfway(struct commit_list *p, int nr)
99 {
100 /*
101 * Don't short-cut something we are not going to return!
102 */
103 if (p->item->object.flags & TREESAME)
104 return 0;
105 if (DEBUG_BISECT)
106 return 0;
107 /*
108 * 2 and 3 are halfway of 5.
109 * 3 is halfway of 6 but 2 and 4 are not.
110 */
111 switch (2 * weight(p) - nr) {
112 case -1: case 0: case 1:
113 return 1;
114 default:
115 return 0;
116 }
117 }
118
119 #if !DEBUG_BISECT
120 #define show_list(a,b,c,d) do { ; } while (0)
121 #else
122 static void show_list(const char *debug, int counted, int nr,
123 struct commit_list *list)
124 {
125 struct commit_list *p;
126
127 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
128
129 for (p = list; p; p = p->next) {
130 struct commit_list *pp;
131 struct commit *commit = p->item;
132 unsigned flags = commit->object.flags;
133 enum object_type type;
134 unsigned long size;
135 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
136 const char *subject_start;
137 int subject_len;
138
139 fprintf(stderr, "%c%c%c ",
140 (flags & TREESAME) ? ' ' : 'T',
141 (flags & UNINTERESTING) ? 'U' : ' ',
142 (flags & COUNTED) ? 'C' : ' ');
143 if (commit->util)
144 fprintf(stderr, "%3d", weight(p));
145 else
146 fprintf(stderr, "---");
147 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
148 for (pp = commit->parents; pp; pp = pp->next)
149 fprintf(stderr, " %.*s", 8,
150 sha1_to_hex(pp->item->object.sha1));
151
152 subject_len = find_commit_subject(buf, &subject_start);
153 if (subject_len)
154 fprintf(stderr, " %.*s", subject_len, subject_start);
155 fprintf(stderr, "\n");
156 }
157 }
158 #endif /* DEBUG_BISECT */
159
160 static struct commit_list *best_bisection(struct commit_list *list, int nr)
161 {
162 struct commit_list *p, *best;
163 int best_distance = -1;
164
165 best = list;
166 for (p = list; p; p = p->next) {
167 int distance;
168 unsigned flags = p->item->object.flags;
169
170 if (flags & TREESAME)
171 continue;
172 distance = weight(p);
173 if (nr - distance < distance)
174 distance = nr - distance;
175 if (distance > best_distance) {
176 best = p;
177 best_distance = distance;
178 }
179 }
180
181 return best;
182 }
183
184 struct commit_dist {
185 struct commit *commit;
186 int distance;
187 };
188
189 static int compare_commit_dist(const void *a_, const void *b_)
190 {
191 struct commit_dist *a, *b;
192
193 a = (struct commit_dist *)a_;
194 b = (struct commit_dist *)b_;
195 if (a->distance != b->distance)
196 return b->distance - a->distance; /* desc sort */
197 return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
198 }
199
200 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
201 {
202 struct commit_list *p;
203 struct commit_dist *array = xcalloc(nr, sizeof(*array));
204 struct strbuf buf = STRBUF_INIT;
205 int cnt, i;
206
207 for (p = list, cnt = 0; p; p = p->next) {
208 int distance;
209 unsigned flags = p->item->object.flags;
210
211 if (flags & TREESAME)
212 continue;
213 distance = weight(p);
214 if (nr - distance < distance)
215 distance = nr - distance;
216 array[cnt].commit = p->item;
217 array[cnt].distance = distance;
218 cnt++;
219 }
220 QSORT(array, cnt, compare_commit_dist);
221 for (p = list, i = 0; i < cnt; i++) {
222 struct object *obj = &(array[i].commit->object);
223
224 strbuf_reset(&buf);
225 strbuf_addf(&buf, "dist=%d", array[i].distance);
226 add_name_decoration(DECORATION_NONE, buf.buf, obj);
227
228 p->item = array[i].commit;
229 if (i < cnt - 1)
230 p = p->next;
231 }
232 free_commit_list(p->next);
233 p->next = NULL;
234 strbuf_release(&buf);
235 free(array);
236 return list;
237 }
238
239 /*
240 * zero or positive weight is the number of interesting commits it can
241 * reach, including itself. Especially, weight = 0 means it does not
242 * reach any tree-changing commits (e.g. just above uninteresting one
243 * but traversal is with pathspec).
244 *
245 * weight = -1 means it has one parent and its distance is yet to
246 * be computed.
247 *
248 * weight = -2 means it has more than one parent and its distance is
249 * unknown. After running count_distance() first, they will get zero
250 * or positive distance.
251 */
252 static struct commit_list *do_find_bisection(struct commit_list *list,
253 int nr, int *weights,
254 int find_all)
255 {
256 int n, counted;
257 struct commit_list *p;
258
259 counted = 0;
260
261 for (n = 0, p = list; p; p = p->next) {
262 struct commit *commit = p->item;
263 unsigned flags = commit->object.flags;
264
265 p->item->util = &weights[n++];
266 switch (count_interesting_parents(commit)) {
267 case 0:
268 if (!(flags & TREESAME)) {
269 weight_set(p, 1);
270 counted++;
271 show_list("bisection 2 count one",
272 counted, nr, list);
273 }
274 /*
275 * otherwise, it is known not to reach any
276 * tree-changing commit and gets weight 0.
277 */
278 break;
279 case 1:
280 weight_set(p, -1);
281 break;
282 default:
283 weight_set(p, -2);
284 break;
285 }
286 }
287
288 show_list("bisection 2 initialize", counted, nr, list);
289
290 /*
291 * If you have only one parent in the resulting set
292 * then you can reach one commit more than that parent
293 * can reach. So we do not have to run the expensive
294 * count_distance() for single strand of pearls.
295 *
296 * However, if you have more than one parents, you cannot
297 * just add their distance and one for yourself, since
298 * they usually reach the same ancestor and you would
299 * end up counting them twice that way.
300 *
301 * So we will first count distance of merges the usual
302 * way, and then fill the blanks using cheaper algorithm.
303 */
304 for (p = list; p; p = p->next) {
305 if (p->item->object.flags & UNINTERESTING)
306 continue;
307 if (weight(p) != -2)
308 continue;
309 weight_set(p, count_distance(p));
310 clear_distance(list);
311
312 /* Does it happen to be at exactly half-way? */
313 if (!find_all && halfway(p, nr))
314 return p;
315 counted++;
316 }
317
318 show_list("bisection 2 count_distance", counted, nr, list);
319
320 while (counted < nr) {
321 for (p = list; p; p = p->next) {
322 struct commit_list *q;
323 unsigned flags = p->item->object.flags;
324
325 if (0 <= weight(p))
326 continue;
327 for (q = p->item->parents; q; q = q->next) {
328 if (q->item->object.flags & UNINTERESTING)
329 continue;
330 if (0 <= weight(q))
331 break;
332 }
333 if (!q)
334 continue;
335
336 /*
337 * weight for p is unknown but q is known.
338 * add one for p itself if p is to be counted,
339 * otherwise inherit it from q directly.
340 */
341 if (!(flags & TREESAME)) {
342 weight_set(p, weight(q)+1);
343 counted++;
344 show_list("bisection 2 count one",
345 counted, nr, list);
346 }
347 else
348 weight_set(p, weight(q));
349
350 /* Does it happen to be at exactly half-way? */
351 if (!find_all && halfway(p, nr))
352 return p;
353 }
354 }
355
356 show_list("bisection 2 counted all", counted, nr, list);
357
358 if (!find_all)
359 return best_bisection(list, nr);
360 else
361 return best_bisection_sorted(list, nr);
362 }
363
364 void find_bisection(struct commit_list **commit_list, int *reaches,
365 int *all, int find_all)
366 {
367 int nr, on_list;
368 struct commit_list *list, *p, *best, *next, *last;
369 int *weights;
370
371 show_list("bisection 2 entry", 0, 0, *commit_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 = *commit_list;
378 p;
379 p = next) {
380 unsigned flags = p->item->object.flags;
381
382 next = p->next;
383 if (flags & UNINTERESTING) {
384 free(p);
385 continue;
386 }
387 p->next = last;
388 last = p;
389 if (!(flags & TREESAME))
390 nr++;
391 on_list++;
392 }
393 list = last;
394 show_list("bisection 2 sorted", 0, nr, list);
395
396 *all = nr;
397 weights = xcalloc(on_list, sizeof(*weights));
398
399 /* Do the real work of finding bisection commit. */
400 best = do_find_bisection(list, nr, weights, find_all);
401 if (best) {
402 if (!find_all) {
403 list->item = best->item;
404 free_commit_list(list->next);
405 best = list;
406 best->next = NULL;
407 }
408 *reaches = weight(best);
409 }
410 free(weights);
411 *commit_list = best;
412 }
413
414 static int register_ref(const char *refname, const struct object_id *oid,
415 int flags, void *cb_data)
416 {
417 struct strbuf good_prefix = STRBUF_INIT;
418 strbuf_addstr(&good_prefix, term_good);
419 strbuf_addstr(&good_prefix, "-");
420
421 if (!strcmp(refname, term_bad)) {
422 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
423 oidcpy(current_bad_oid, oid);
424 } else if (starts_with(refname, good_prefix.buf)) {
425 oid_array_append(&good_revs, oid);
426 } else if (starts_with(refname, "skip-")) {
427 oid_array_append(&skipped_revs, oid);
428 }
429
430 strbuf_release(&good_prefix);
431
432 return 0;
433 }
434
435 static int read_bisect_refs(void)
436 {
437 return for_each_ref_in("refs/bisect/", register_ref, NULL);
438 }
439
440 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
441 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
442 static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
443 static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
444 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
445 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
446 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
447 static GIT_PATH_FUNC(git_path_head_name, "head-name")
448
449 static void read_bisect_paths(struct argv_array *array)
450 {
451 struct strbuf str = STRBUF_INIT;
452 const char *filename = git_path_bisect_names();
453 FILE *fp = xfopen(filename, "r");
454
455 while (strbuf_getline_lf(&str, fp) != EOF) {
456 strbuf_trim(&str);
457 if (sq_dequote_to_argv_array(str.buf, array))
458 die(_("Badly quoted content in file '%s': %s"),
459 filename, str.buf);
460 }
461
462 strbuf_release(&str);
463 fclose(fp);
464 }
465
466 static char *join_sha1_array_hex(struct oid_array *array, char delim)
467 {
468 struct strbuf joined_hexs = STRBUF_INIT;
469 int i;
470
471 for (i = 0; i < array->nr; i++) {
472 strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
473 if (i + 1 < array->nr)
474 strbuf_addch(&joined_hexs, delim);
475 }
476
477 return strbuf_detach(&joined_hexs, NULL);
478 }
479
480 /*
481 * In this function, passing a not NULL skipped_first is very special.
482 * It means that we want to know if the first commit in the list is
483 * skipped because we will want to test a commit away from it if it is
484 * indeed skipped.
485 * So if the first commit is skipped, we cannot take the shortcut to
486 * just "return list" when we find the first non skipped commit, we
487 * have to return a fully filtered list.
488 *
489 * We use (*skipped_first == -1) to mean "it has been found that the
490 * first commit is not skipped". In this case *skipped_first is set back
491 * to 0 just before the function returns.
492 */
493 struct commit_list *filter_skipped(struct commit_list *list,
494 struct commit_list **tried,
495 int show_all,
496 int *count,
497 int *skipped_first)
498 {
499 struct commit_list *filtered = NULL, **f = &filtered;
500
501 *tried = NULL;
502
503 if (skipped_first)
504 *skipped_first = 0;
505 if (count)
506 *count = 0;
507
508 if (!skipped_revs.nr)
509 return list;
510
511 while (list) {
512 struct commit_list *next = list->next;
513 list->next = NULL;
514 if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
515 if (skipped_first && !*skipped_first)
516 *skipped_first = 1;
517 /* Move current to tried list */
518 *tried = list;
519 tried = &list->next;
520 } else {
521 if (!show_all) {
522 if (!skipped_first || !*skipped_first)
523 return list;
524 } else if (skipped_first && !*skipped_first) {
525 /* This means we know it's not skipped */
526 *skipped_first = -1;
527 }
528 /* Move current to filtered list */
529 *f = list;
530 f = &list->next;
531 if (count)
532 (*count)++;
533 }
534 list = next;
535 }
536
537 if (skipped_first && *skipped_first == -1)
538 *skipped_first = 0;
539
540 return filtered;
541 }
542
543 #define PRN_MODULO 32768
544
545 /*
546 * This is a pseudo random number generator based on "man 3 rand".
547 * It is not used properly because the seed is the argument and it
548 * is increased by one between each call, but that should not matter
549 * for this application.
550 */
551 static unsigned get_prn(unsigned count) {
552 count = count * 1103515245 + 12345;
553 return (count/65536) % PRN_MODULO;
554 }
555
556 /*
557 * Custom integer square root from
558 * https://en.wikipedia.org/wiki/Integer_square_root
559 */
560 static int sqrti(int val)
561 {
562 float d, x = val;
563
564 if (val == 0)
565 return 0;
566
567 do {
568 float y = (x + (float)val / x) / 2;
569 d = (y > x) ? y - x : x - y;
570 x = y;
571 } while (d >= 0.5);
572
573 return (int)x;
574 }
575
576 static struct commit_list *skip_away(struct commit_list *list, int count)
577 {
578 struct commit_list *cur, *previous;
579 int prn, index, i;
580
581 prn = get_prn(count);
582 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
583
584 cur = list;
585 previous = NULL;
586
587 for (i = 0; cur; cur = cur->next, i++) {
588 if (i == index) {
589 if (oidcmp(&cur->item->object.oid, current_bad_oid))
590 return cur;
591 if (previous)
592 return previous;
593 return list;
594 }
595 previous = cur;
596 }
597
598 return list;
599 }
600
601 static struct commit_list *managed_skipped(struct commit_list *list,
602 struct commit_list **tried)
603 {
604 int count, skipped_first;
605
606 *tried = NULL;
607
608 if (!skipped_revs.nr)
609 return list;
610
611 list = filter_skipped(list, tried, 0, &count, &skipped_first);
612
613 if (!skipped_first)
614 return list;
615
616 return skip_away(list, count);
617 }
618
619 static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
620 const char *bad_format, const char *good_format,
621 int read_paths)
622 {
623 struct argv_array rev_argv = ARGV_ARRAY_INIT;
624 int i;
625
626 init_revisions(revs, prefix);
627 revs->abbrev = 0;
628 revs->commit_format = CMIT_FMT_UNSPECIFIED;
629
630 /* rev_argv.argv[0] will be ignored by setup_revisions */
631 argv_array_push(&rev_argv, "bisect_rev_setup");
632 argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
633 for (i = 0; i < good_revs.nr; i++)
634 argv_array_pushf(&rev_argv, good_format,
635 oid_to_hex(good_revs.oid + i));
636 argv_array_push(&rev_argv, "--");
637 if (read_paths)
638 read_bisect_paths(&rev_argv);
639
640 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
641 /* XXX leak rev_argv, as "revs" may still be pointing to it */
642 }
643
644 static void bisect_common(struct rev_info *revs)
645 {
646 if (prepare_revision_walk(revs))
647 die("revision walk setup failed");
648 if (revs->tree_objects)
649 mark_edges_uninteresting(revs, NULL);
650 }
651
652 static void exit_if_skipped_commits(struct commit_list *tried,
653 const struct object_id *bad)
654 {
655 if (!tried)
656 return;
657
658 printf("There are only 'skip'ped commits left to test.\n"
659 "The first %s commit could be any of:\n", term_bad);
660
661 for ( ; tried; tried = tried->next)
662 printf("%s\n", oid_to_hex(&tried->item->object.oid));
663
664 if (bad)
665 printf("%s\n", oid_to_hex(bad));
666 printf(_("We cannot bisect more!\n"));
667 exit(2);
668 }
669
670 static int is_expected_rev(const struct object_id *oid)
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_or_warn(filename, "r");
682 if (!fp)
683 return 0;
684
685 if (strbuf_getline_lf(&str, fp) != EOF)
686 res = !strcmp(str.buf, oid_to_hex(oid));
687
688 strbuf_release(&str);
689 fclose(fp);
690
691 return res;
692 }
693
694 static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
695 {
696 char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
697
698 memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
699 update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
700
701 argv_checkout[2] = bisect_rev_hex;
702 if (no_checkout) {
703 update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
704 UPDATE_REFS_DIE_ON_ERR);
705 } else {
706 int res;
707 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
708 if (res)
709 exit(res);
710 }
711
712 argv_show_branch[1] = bisect_rev_hex;
713 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
714 }
715
716 static struct commit *get_commit_reference(const struct object_id *oid)
717 {
718 struct commit *r = lookup_commit_reference(oid);
719 if (!r)
720 die(_("Not a valid commit name %s"), oid_to_hex(oid));
721 return r;
722 }
723
724 static struct commit **get_bad_and_good_commits(int *rev_nr)
725 {
726 struct commit **rev;
727 int i, n = 0;
728
729 ALLOC_ARRAY(rev, 1 + good_revs.nr);
730 rev[n++] = get_commit_reference(current_bad_oid);
731 for (i = 0; i < good_revs.nr; i++)
732 rev[n++] = get_commit_reference(good_revs.oid + i);
733 *rev_nr = n;
734
735 return rev;
736 }
737
738 static void handle_bad_merge_base(void)
739 {
740 if (is_expected_rev(current_bad_oid)) {
741 char *bad_hex = oid_to_hex(current_bad_oid);
742 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
743 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
744 fprintf(stderr, _("The merge base %s is bad.\n"
745 "This means the bug has been fixed "
746 "between %s and [%s].\n"),
747 bad_hex, bad_hex, good_hex);
748 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
749 fprintf(stderr, _("The merge base %s is new.\n"
750 "The property has changed "
751 "between %s and [%s].\n"),
752 bad_hex, bad_hex, good_hex);
753 } else {
754 fprintf(stderr, _("The merge base %s is %s.\n"
755 "This means the first '%s' commit is "
756 "between %s and [%s].\n"),
757 bad_hex, term_bad, term_good, bad_hex, good_hex);
758 }
759 exit(3);
760 }
761
762 fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
763 "git bisect cannot work properly in this case.\n"
764 "Maybe you mistook %s and %s revs?\n"),
765 term_good, term_bad, term_good, term_bad);
766 exit(1);
767 }
768
769 static void handle_skipped_merge_base(const struct object_id *mb)
770 {
771 char *mb_hex = oid_to_hex(mb);
772 char *bad_hex = oid_to_hex(current_bad_oid);
773 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
774
775 warning(_("the merge base between %s and [%s] "
776 "must be skipped.\n"
777 "So we cannot be sure the first %s commit is "
778 "between %s and %s.\n"
779 "We continue anyway."),
780 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
781 free(good_hex);
782 }
783
784 /*
785 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
786 *
787 * - If one is "bad" (or "new"), it means the user assumed something wrong
788 * and we must exit with a non 0 error code.
789 * - If one is "good" (or "old"), that's good, we have nothing to do.
790 * - If one is "skipped", we can't know but we should warn.
791 * - If we don't know, we should check it out and ask the user to test.
792 */
793 static void check_merge_bases(int no_checkout)
794 {
795 struct commit_list *result;
796 int rev_nr;
797 struct commit **rev = get_bad_and_good_commits(&rev_nr);
798
799 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
800
801 for (; result; result = result->next) {
802 const struct object_id *mb = &result->item->object.oid;
803 if (!oidcmp(mb, current_bad_oid)) {
804 handle_bad_merge_base();
805 } else if (0 <= oid_array_lookup(&good_revs, mb)) {
806 continue;
807 } else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
808 handle_skipped_merge_base(mb);
809 } else {
810 printf(_("Bisecting: a merge base must be tested\n"));
811 exit(bisect_checkout(mb, no_checkout));
812 }
813 }
814
815 free(rev);
816 free_commit_list(result);
817 }
818
819 static int check_ancestors(const char *prefix)
820 {
821 struct rev_info revs;
822 struct object_array pending_copy;
823 int res;
824
825 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
826
827 /* Save pending objects, so they can be cleaned up later. */
828 pending_copy = revs.pending;
829 revs.leak_pending = 1;
830
831 /*
832 * bisect_common calls prepare_revision_walk right away, which
833 * (together with .leak_pending = 1) makes us the sole owner of
834 * the list of pending objects.
835 */
836 bisect_common(&revs);
837 res = (revs.commits != NULL);
838
839 /* Clean up objects used, as they will be reused. */
840 clear_commit_marks_for_object_array(&pending_copy, ALL_REV_FLAGS);
841
842 object_array_clear(&pending_copy);
843
844 return res;
845 }
846
847 /*
848 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
849 * ancestor of the "bad" rev.
850 *
851 * If that's not the case, we need to check the merge bases.
852 * If a merge base must be tested by the user, its source code will be
853 * checked out to be tested by the user and we will exit.
854 */
855 static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
856 {
857 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
858 struct stat st;
859 int fd;
860
861 if (!current_bad_oid)
862 die(_("a %s revision is needed"), term_bad);
863
864 /* Check if file BISECT_ANCESTORS_OK exists. */
865 if (!stat(filename, &st) && S_ISREG(st.st_mode))
866 goto done;
867
868 /* Bisecting with no good rev is ok. */
869 if (good_revs.nr == 0)
870 goto done;
871
872 /* Check if all good revs are ancestor of the bad rev. */
873 if (check_ancestors(prefix))
874 check_merge_bases(no_checkout);
875
876 /* Create file BISECT_ANCESTORS_OK. */
877 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
878 if (fd < 0)
879 warning_errno(_("could not create file '%s'"),
880 filename);
881 else
882 close(fd);
883 done:
884 free(filename);
885 }
886
887 /*
888 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
889 */
890 static void show_diff_tree(const char *prefix, struct commit *commit)
891 {
892 struct rev_info opt;
893
894 /* diff-tree init */
895 init_revisions(&opt, prefix);
896 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
897 opt.abbrev = 0;
898 opt.diff = 1;
899
900 /* This is what "--pretty" does */
901 opt.verbose_header = 1;
902 opt.use_terminator = 0;
903 opt.commit_format = CMIT_FMT_DEFAULT;
904
905 /* diff-tree init */
906 if (!opt.diffopt.output_format)
907 opt.diffopt.output_format = DIFF_FORMAT_RAW;
908
909 setup_revisions(0, NULL, &opt, NULL);
910 log_tree_commit(&opt, commit);
911 }
912
913 /*
914 * The terms used for this bisect session are stored in BISECT_TERMS.
915 * We read them and store them to adapt the messages accordingly.
916 * Default is bad/good.
917 */
918 void read_bisect_terms(const char **read_bad, const char **read_good)
919 {
920 struct strbuf str = STRBUF_INIT;
921 const char *filename = git_path_bisect_terms();
922 FILE *fp = fopen(filename, "r");
923
924 if (!fp) {
925 if (errno == ENOENT) {
926 *read_bad = "bad";
927 *read_good = "good";
928 return;
929 } else {
930 die_errno(_("could not read file '%s'"), filename);
931 }
932 } else {
933 strbuf_getline_lf(&str, fp);
934 *read_bad = strbuf_detach(&str, NULL);
935 strbuf_getline_lf(&str, fp);
936 *read_good = strbuf_detach(&str, NULL);
937 }
938 strbuf_release(&str);
939 fclose(fp);
940 }
941
942 /*
943 * We use the convention that exiting with an exit code 10 means that
944 * the bisection process finished successfully.
945 * In this case the calling shell script should exit 0.
946 *
947 * If no_checkout is non-zero, the bisection process does not
948 * checkout the trial commit but instead simply updates BISECT_HEAD.
949 */
950 int bisect_next_all(const char *prefix, int no_checkout)
951 {
952 struct rev_info revs;
953 struct commit_list *tried;
954 int reaches = 0, all = 0, nr, steps;
955 struct object_id *bisect_rev;
956 char *steps_msg;
957
958 read_bisect_terms(&term_bad, &term_good);
959 if (read_bisect_refs())
960 die(_("reading bisect refs failed"));
961
962 check_good_are_ancestors_of_bad(prefix, no_checkout);
963
964 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
965 revs.limited = 1;
966
967 bisect_common(&revs);
968
969 find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
970 revs.commits = managed_skipped(revs.commits, &tried);
971
972 if (!revs.commits) {
973 /*
974 * We should exit here only if the "bad"
975 * commit is also a "skip" commit.
976 */
977 exit_if_skipped_commits(tried, NULL);
978
979 printf(_("%s was both %s and %s\n"),
980 oid_to_hex(current_bad_oid),
981 term_good,
982 term_bad);
983 exit(1);
984 }
985
986 if (!all) {
987 fprintf(stderr, _("No testable commit found.\n"
988 "Maybe you started with bad path parameters?\n"));
989 exit(4);
990 }
991
992 bisect_rev = &revs.commits->item->object.oid;
993
994 if (!oidcmp(bisect_rev, current_bad_oid)) {
995 exit_if_skipped_commits(tried, current_bad_oid);
996 printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
997 term_bad);
998 show_diff_tree(prefix, revs.commits->item);
999 /* This means the bisection process succeeded. */
1000 exit(10);
1001 }
1002
1003 nr = all - reaches - 1;
1004 steps = estimate_bisect_steps(all);
1005
1006 steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
1007 steps), steps);
1008 /*
1009 * TRANSLATORS: the last %s will be replaced with "(roughly %d
1010 * steps)" translation.
1011 */
1012 printf(Q_("Bisecting: %d revision left to test after this %s\n",
1013 "Bisecting: %d revisions left to test after this %s\n",
1014 nr), nr, steps_msg);
1015 free(steps_msg);
1016
1017 return bisect_checkout(bisect_rev, no_checkout);
1018 }
1019
1020 static inline int log2i(int n)
1021 {
1022 int log2 = 0;
1023
1024 for (; n > 1; n >>= 1)
1025 log2++;
1026
1027 return log2;
1028 }
1029
1030 static inline int exp2i(int n)
1031 {
1032 return 1 << n;
1033 }
1034
1035 /*
1036 * Estimate the number of bisect steps left (after the current step)
1037 *
1038 * For any x between 0 included and 2^n excluded, the probability for
1039 * n - 1 steps left looks like:
1040 *
1041 * P(2^n + x) == (2^n - x) / (2^n + x)
1042 *
1043 * and P(2^n + x) < 0.5 means 2^n < 3x
1044 */
1045 int estimate_bisect_steps(int all)
1046 {
1047 int n, x, e;
1048
1049 if (all < 3)
1050 return 0;
1051
1052 n = log2i(all);
1053 e = exp2i(n);
1054 x = all - e;
1055
1056 return (e < 3 * x) ? n : n - 1;
1057 }
1058
1059 static int mark_for_removal(const char *refname, const struct object_id *oid,
1060 int flag, void *cb_data)
1061 {
1062 struct string_list *refs = cb_data;
1063 char *ref = xstrfmt("refs/bisect%s", refname);
1064 string_list_append(refs, ref);
1065 return 0;
1066 }
1067
1068 int bisect_clean_state(void)
1069 {
1070 int result = 0;
1071
1072 /* There may be some refs packed during bisection */
1073 struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
1074 for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
1075 string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
1076 result = delete_refs("bisect: remove", &refs_for_removal, REF_NODEREF);
1077 refs_for_removal.strdup_strings = 1;
1078 string_list_clear(&refs_for_removal, 0);
1079 unlink_or_warn(git_path_bisect_expected_rev());
1080 unlink_or_warn(git_path_bisect_ancestors_ok());
1081 unlink_or_warn(git_path_bisect_log());
1082 unlink_or_warn(git_path_bisect_names());
1083 unlink_or_warn(git_path_bisect_run());
1084 unlink_or_warn(git_path_bisect_terms());
1085 /* Cleanup head-name if it got left by an old version of git-bisect */
1086 unlink_or_warn(git_path_head_name());
1087 /*
1088 * Cleanup BISECT_START last to support the --no-checkout option
1089 * introduced in the commit 4796e823a.
1090 */
1091 unlink_or_warn(git_path_bisect_start());
1092
1093 return result;
1094 }