freshlybakedca.ke
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1#define USE_THE_REPOSITORY_VARIABLE
2#define DISABLE_SIGN_COMPARE_WARNINGS
3
4#include "git-compat-util.h"
5#include "config.h"
6#include "commit.h"
7#include "diff.h"
8#include "environment.h"
9#include "gettext.h"
10#include "hex.h"
11#include "revision.h"
12#include "refs.h"
13#include "list-objects.h"
14#include "quote.h"
15#include "run-command.h"
16#include "log-tree.h"
17#include "bisect.h"
18#include "oid-array.h"
19#include "strvec.h"
20#include "commit-slab.h"
21#include "commit-reach.h"
22#include "object-name.h"
23#include "odb.h"
24#include "path.h"
25#include "dir.h"
26
27static struct oid_array good_revs;
28static struct oid_array skipped_revs;
29
30static struct object_id *current_bad_oid;
31
32static char *term_bad;
33static char *term_good;
34
35/* Remember to update object flag allocation in object.h */
36#define COUNTED (1u<<16)
37
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 */
45static int count_distance(struct commit_list *entry)
46{
47 int nr = 0;
48
49 while (entry) {
50 struct commit *commit = entry->item;
51 struct commit_list *p;
52
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 }
68
69 return nr;
70}
71
72static 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}
80
81define_commit_slab(commit_weight, int *);
82static struct commit_weight commit_weight;
83
84#define DEBUG_BISECT 0
85
86static inline int weight(struct commit_list *elem)
87{
88 return **commit_weight_at(&commit_weight, elem->item);
89}
90
91static inline void weight_set(struct commit_list *elem, int weight)
92{
93 **commit_weight_at(&commit_weight, elem->item) = weight;
94}
95
96static int count_interesting_parents(struct commit *commit, unsigned bisect_flags)
97{
98 struct commit_list *p;
99 int count;
100
101 for (count = 0, p = commit->parents; p; p = p->next) {
102 if (!(p->item->object.flags & UNINTERESTING))
103 count++;
104 if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
105 break;
106 }
107 return count;
108}
109
110static inline int approx_halfway(struct commit_list *p, int nr)
111{
112 int diff;
113
114 /*
115 * Don't short-cut something we are not going to return!
116 */
117 if (p->item->object.flags & TREESAME)
118 return 0;
119 if (DEBUG_BISECT)
120 return 0;
121 /*
122 * For small number of commits 2 and 3 are halfway of 5, and
123 * 3 is halfway of 6 but 2 and 4 are not.
124 */
125 diff = 2 * weight(p) - nr;
126 switch (diff) {
127 case -1: case 0: case 1:
128 return 1;
129 default:
130 /*
131 * For large number of commits we are not so strict, it's
132 * good enough if it's within ~0.1% of the halfway point,
133 * e.g. 5000 is exactly halfway of 10000, but we consider
134 * the values [4996, 5004] as halfway as well.
135 */
136 if (abs(diff) < nr / 1024)
137 return 1;
138 return 0;
139 }
140}
141
142static void show_list(const char *debug, int counted, int nr,
143 struct commit_list *list)
144{
145 struct commit_list *p;
146
147 if (!DEBUG_BISECT)
148 return;
149
150 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
151
152 for (p = list; p; p = p->next) {
153 struct commit_list *pp;
154 struct commit *commit = p->item;
155 unsigned commit_flags = commit->object.flags;
156 enum object_type type;
157 unsigned long size;
158 char *buf = odb_read_object(the_repository->objects,
159 &commit->object.oid, &type,
160 &size);
161 const char *subject_start;
162 int subject_len;
163
164 if (!buf)
165 die(_("unable to read %s"), oid_to_hex(&commit->object.oid));
166
167 fprintf(stderr, "%c%c%c ",
168 (commit_flags & TREESAME) ? ' ' : 'T',
169 (commit_flags & UNINTERESTING) ? 'U' : ' ',
170 (commit_flags & COUNTED) ? 'C' : ' ');
171 if (*commit_weight_at(&commit_weight, p->item))
172 fprintf(stderr, "%3d", weight(p));
173 else
174 fprintf(stderr, "---");
175 fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
176 for (pp = commit->parents; pp; pp = pp->next)
177 fprintf(stderr, " %.*s", 8,
178 oid_to_hex(&pp->item->object.oid));
179
180 subject_len = find_commit_subject(buf, &subject_start);
181 if (subject_len)
182 fprintf(stderr, " %.*s", subject_len, subject_start);
183 fprintf(stderr, "\n");
184 }
185}
186
187static struct commit_list *best_bisection(struct commit_list *list, int nr)
188{
189 struct commit_list *p, *best;
190 int best_distance = -1;
191
192 best = list;
193 for (p = list; p; p = p->next) {
194 int distance;
195 unsigned commit_flags = p->item->object.flags;
196
197 if (commit_flags & TREESAME)
198 continue;
199 distance = weight(p);
200 if (nr - distance < distance)
201 distance = nr - distance;
202 if (distance > best_distance) {
203 best = p;
204 best_distance = distance;
205 }
206 }
207
208 return best;
209}
210
211struct commit_dist {
212 struct commit *commit;
213 int distance;
214};
215
216static int compare_commit_dist(const void *a_, const void *b_)
217{
218 struct commit_dist *a, *b;
219
220 a = (struct commit_dist *)a_;
221 b = (struct commit_dist *)b_;
222 if (a->distance != b->distance)
223 return b->distance - a->distance; /* desc sort */
224 return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
225}
226
227static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
228{
229 struct commit_list *p;
230 struct commit_dist *array = xcalloc(nr, sizeof(*array));
231 struct strbuf buf = STRBUF_INIT;
232 int cnt, i;
233
234 for (p = list, cnt = 0; p; p = p->next) {
235 int distance;
236 unsigned commit_flags = p->item->object.flags;
237
238 if (commit_flags & TREESAME)
239 continue;
240 distance = weight(p);
241 if (nr - distance < distance)
242 distance = nr - distance;
243 array[cnt].commit = p->item;
244 array[cnt].distance = distance;
245 cnt++;
246 }
247 QSORT(array, cnt, compare_commit_dist);
248 for (p = list, i = 0; i < cnt; i++) {
249 struct object *obj = &(array[i].commit->object);
250
251 strbuf_reset(&buf);
252 strbuf_addf(&buf, "dist=%d", array[i].distance);
253 add_name_decoration(DECORATION_NONE, buf.buf, obj);
254
255 p->item = array[i].commit;
256 if (i < cnt - 1)
257 p = p->next;
258 }
259 if (p) {
260 free_commit_list(p->next);
261 p->next = NULL;
262 }
263 strbuf_release(&buf);
264 free(array);
265 return list;
266}
267
268/*
269 * zero or positive weight is the number of interesting commits it can
270 * reach, including itself. Especially, weight = 0 means it does not
271 * reach any tree-changing commits (e.g. just above uninteresting one
272 * but traversal is with pathspec).
273 *
274 * weight = -1 means it has one parent and its distance is yet to
275 * be computed.
276 *
277 * weight = -2 means it has more than one parent and its distance is
278 * unknown. After running count_distance() first, they will get zero
279 * or positive distance.
280 */
281static struct commit_list *do_find_bisection(struct commit_list *list,
282 int nr, int *weights,
283 unsigned bisect_flags)
284{
285 int n, counted;
286 struct commit_list *p;
287
288 counted = 0;
289
290 for (n = 0, p = list; p; p = p->next) {
291 struct commit *commit = p->item;
292 unsigned commit_flags = commit->object.flags;
293
294 *commit_weight_at(&commit_weight, p->item) = &weights[n++];
295 switch (count_interesting_parents(commit, bisect_flags)) {
296 case 0:
297 if (!(commit_flags & TREESAME)) {
298 weight_set(p, 1);
299 counted++;
300 show_list("bisection 2 count one",
301 counted, nr, list);
302 }
303 /*
304 * otherwise, it is known not to reach any
305 * tree-changing commit and gets weight 0.
306 */
307 break;
308 case 1:
309 weight_set(p, -1);
310 break;
311 default:
312 weight_set(p, -2);
313 break;
314 }
315 }
316
317 show_list("bisection 2 initialize", counted, nr, list);
318
319 /*
320 * If you have only one parent in the resulting set
321 * then you can reach one commit more than that parent
322 * can reach. So we do not have to run the expensive
323 * count_distance() for single strand of pearls.
324 *
325 * However, if you have more than one parents, you cannot
326 * just add their distance and one for yourself, since
327 * they usually reach the same ancestor and you would
328 * end up counting them twice that way.
329 *
330 * So we will first count distance of merges the usual
331 * way, and then fill the blanks using cheaper algorithm.
332 */
333 for (p = list; p; p = p->next) {
334 if (p->item->object.flags & UNINTERESTING)
335 continue;
336 if (weight(p) != -2)
337 continue;
338 if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
339 BUG("shouldn't be calling count-distance in fp mode");
340 weight_set(p, count_distance(p));
341 clear_distance(list);
342
343 /* Does it happen to be at half-way? */
344 if (!(bisect_flags & FIND_BISECTION_ALL) &&
345 approx_halfway(p, nr))
346 return p;
347 counted++;
348 }
349
350 show_list("bisection 2 count_distance", counted, nr, list);
351
352 while (counted < nr) {
353 for (p = list; p; p = p->next) {
354 struct commit_list *q;
355 unsigned commit_flags = p->item->object.flags;
356
357 if (0 <= weight(p))
358 continue;
359
360 for (q = p->item->parents;
361 q;
362 q = bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY ? NULL : q->next) {
363 if (q->item->object.flags & UNINTERESTING)
364 continue;
365 if (0 <= weight(q))
366 break;
367 }
368 if (!q)
369 continue;
370
371 /*
372 * weight for p is unknown but q is known.
373 * add one for p itself if p is to be counted,
374 * otherwise inherit it from q directly.
375 */
376 if (!(commit_flags & TREESAME)) {
377 weight_set(p, weight(q)+1);
378 counted++;
379 show_list("bisection 2 count one",
380 counted, nr, list);
381 }
382 else
383 weight_set(p, weight(q));
384
385 /* Does it happen to be at half-way? */
386 if (!(bisect_flags & FIND_BISECTION_ALL) &&
387 approx_halfway(p, nr))
388 return p;
389 }
390 }
391
392 show_list("bisection 2 counted all", counted, nr, list);
393
394 if (!(bisect_flags & FIND_BISECTION_ALL))
395 return best_bisection(list, nr);
396 else
397 return best_bisection_sorted(list, nr);
398}
399
400void find_bisection(struct commit_list **commit_list, int *reaches,
401 int *all, unsigned bisect_flags)
402{
403 int nr, on_list;
404 struct commit_list *list, *p, *best, *next, *last;
405 int *weights;
406
407 show_list("bisection 2 entry", 0, 0, *commit_list);
408 init_commit_weight(&commit_weight);
409
410 /*
411 * Count the number of total and tree-changing items on the
412 * list, while reversing the list.
413 */
414 for (nr = on_list = 0, last = NULL, p = *commit_list;
415 p;
416 p = next) {
417 unsigned commit_flags = p->item->object.flags;
418
419 next = p->next;
420 if (commit_flags & UNINTERESTING) {
421 free(p);
422 continue;
423 }
424 p->next = last;
425 last = p;
426 if (!(commit_flags & TREESAME))
427 nr++;
428 on_list++;
429 }
430 list = last;
431 show_list("bisection 2 sorted", 0, nr, list);
432
433 *all = nr;
434 CALLOC_ARRAY(weights, on_list);
435
436 /* Do the real work of finding bisection commit. */
437 best = do_find_bisection(list, nr, weights, bisect_flags);
438 if (best) {
439 if (!(bisect_flags & FIND_BISECTION_ALL)) {
440 list->item = best->item;
441 free_commit_list(list->next);
442 best = list;
443 best->next = NULL;
444 }
445 *reaches = weight(best);
446 }
447 *commit_list = best;
448
449 free(weights);
450 clear_commit_weight(&commit_weight);
451}
452
453static int register_ref(const char *refname, const char *referent UNUSED, const struct object_id *oid,
454 int flags UNUSED, void *cb_data UNUSED)
455{
456 struct strbuf good_prefix = STRBUF_INIT;
457 strbuf_addstr(&good_prefix, term_good);
458 strbuf_addstr(&good_prefix, "-");
459
460 if (!strcmp(refname, term_bad)) {
461 free(current_bad_oid);
462 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
463 oidcpy(current_bad_oid, oid);
464 } else if (starts_with(refname, good_prefix.buf)) {
465 oid_array_append(&good_revs, oid);
466 } else if (starts_with(refname, "skip-")) {
467 oid_array_append(&skipped_revs, oid);
468 }
469
470 strbuf_release(&good_prefix);
471
472 return 0;
473}
474
475static int read_bisect_refs(void)
476{
477 return refs_for_each_ref_in(get_main_ref_store(the_repository),
478 "refs/bisect/", register_ref, NULL);
479}
480
481static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
482static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
483static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
484static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
485static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
486static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
487static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
488
489static void read_bisect_paths(struct strvec *array)
490{
491 struct strbuf str = STRBUF_INIT;
492 const char *filename = git_path_bisect_names();
493 FILE *fp = xfopen(filename, "r");
494
495 while (strbuf_getline_lf(&str, fp) != EOF) {
496 strbuf_trim(&str);
497 if (sq_dequote_to_strvec(str.buf, array))
498 die(_("Badly quoted content in file '%s': %s"),
499 filename, str.buf);
500 }
501
502 strbuf_release(&str);
503 fclose(fp);
504}
505
506static char *join_oid_array_hex(struct oid_array *array, char delim)
507{
508 struct strbuf joined_hexs = STRBUF_INIT;
509 int i;
510
511 for (i = 0; i < array->nr; i++) {
512 strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
513 if (i + 1 < array->nr)
514 strbuf_addch(&joined_hexs, delim);
515 }
516
517 return strbuf_detach(&joined_hexs, NULL);
518}
519
520/*
521 * In this function, passing a not NULL skipped_first is very special.
522 * It means that we want to know if the first commit in the list is
523 * skipped because we will want to test a commit away from it if it is
524 * indeed skipped.
525 * So if the first commit is skipped, we cannot take the shortcut to
526 * just "return list" when we find the first non skipped commit, we
527 * have to return a fully filtered list.
528 *
529 * We use (*skipped_first == -1) to mean "it has been found that the
530 * first commit is not skipped". In this case *skipped_first is set back
531 * to 0 just before the function returns.
532 */
533struct commit_list *filter_skipped(struct commit_list *list,
534 struct commit_list **tried,
535 int show_all,
536 int *count,
537 int *skipped_first)
538{
539 struct commit_list *filtered = NULL, **f = &filtered;
540
541 *tried = NULL;
542
543 if (skipped_first)
544 *skipped_first = 0;
545 if (count)
546 *count = 0;
547
548 if (!skipped_revs.nr)
549 return list;
550
551 while (list) {
552 struct commit_list *next = list->next;
553 list->next = NULL;
554 if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
555 if (skipped_first && !*skipped_first)
556 *skipped_first = 1;
557 /* Move current to tried list */
558 *tried = list;
559 tried = &list->next;
560 } else {
561 if (!show_all) {
562 if (!skipped_first || !*skipped_first) {
563 free_commit_list(next);
564 free_commit_list(filtered);
565 return list;
566 }
567 } else if (skipped_first && !*skipped_first) {
568 /* This means we know it's not skipped */
569 *skipped_first = -1;
570 }
571 /* Move current to filtered list */
572 *f = list;
573 f = &list->next;
574 if (count)
575 (*count)++;
576 }
577 list = next;
578 }
579
580 if (skipped_first && *skipped_first == -1)
581 *skipped_first = 0;
582
583 return filtered;
584}
585
586#define PRN_MODULO 32768
587
588/*
589 * This is a pseudo random number generator based on "man 3 rand".
590 * It is not used properly because the seed is the argument and it
591 * is increased by one between each call, but that should not matter
592 * for this application.
593 */
594static unsigned get_prn(unsigned count)
595{
596 count = count * 1103515245 + 12345;
597 return (count/65536) % PRN_MODULO;
598}
599
600/*
601 * Custom integer square root from
602 * https://en.wikipedia.org/wiki/Integer_square_root
603 */
604static int sqrti(int val)
605{
606 float d, x = val;
607
608 if (!val)
609 return 0;
610
611 do {
612 float y = (x + (float)val / x) / 2;
613 d = (y > x) ? y - x : x - y;
614 x = y;
615 } while (d >= 0.5);
616
617 return (int)x;
618}
619
620static struct commit_list *skip_away(struct commit_list *list, int count)
621{
622 struct commit_list *cur, *previous, *result = list;
623 int prn, index, i;
624
625 prn = get_prn(count);
626 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
627
628 cur = list;
629 previous = NULL;
630
631 for (i = 0; cur; cur = cur->next, i++) {
632 if (i == index) {
633 if (!oideq(&cur->item->object.oid, current_bad_oid))
634 result = cur;
635 else if (previous)
636 result = previous;
637 else
638 result = list;
639 break;
640 }
641 previous = cur;
642 }
643
644 for (cur = list; cur != result; ) {
645 struct commit_list *next = cur->next;
646 free(cur);
647 cur = next;
648 }
649
650 return result;
651}
652
653static struct commit_list *managed_skipped(struct commit_list *list,
654 struct commit_list **tried)
655{
656 int count, skipped_first;
657
658 *tried = NULL;
659
660 if (!skipped_revs.nr)
661 return list;
662
663 list = filter_skipped(list, tried, 0, &count, &skipped_first);
664
665 if (!skipped_first)
666 return list;
667
668 return skip_away(list, count);
669}
670
671static void bisect_rev_setup(struct repository *r, struct rev_info *revs,
672 struct strvec *rev_argv,
673 const char *prefix,
674 const char *bad_format, const char *good_format,
675 int read_paths)
676{
677 int i;
678
679 repo_init_revisions(r, revs, prefix);
680 revs->abbrev = 0;
681 revs->commit_format = CMIT_FMT_UNSPECIFIED;
682
683 /* rev_argv.argv[0] will be ignored by setup_revisions */
684 strvec_push(rev_argv, "bisect_rev_setup");
685 strvec_pushf(rev_argv, bad_format, oid_to_hex(current_bad_oid));
686 for (i = 0; i < good_revs.nr; i++)
687 strvec_pushf(rev_argv, good_format,
688 oid_to_hex(good_revs.oid + i));
689 strvec_push(rev_argv, "--");
690 if (read_paths)
691 read_bisect_paths(rev_argv);
692
693 setup_revisions_from_strvec(rev_argv, revs, NULL);
694}
695
696static void bisect_common(struct rev_info *revs)
697{
698 if (prepare_revision_walk(revs))
699 die("revision walk setup failed");
700 if (revs->tree_objects)
701 mark_edges_uninteresting(revs, NULL, 0);
702}
703
704static enum bisect_error error_if_skipped_commits(struct commit_list *tried,
705 const struct object_id *bad)
706{
707 if (!tried)
708 return BISECT_OK;
709
710 printf("There are only 'skip'ped commits left to test.\n"
711 "The first %s commit could be any of:\n", term_bad);
712
713 for ( ; tried; tried = tried->next)
714 printf("%s\n", oid_to_hex(&tried->item->object.oid));
715
716 if (bad)
717 printf("%s\n", oid_to_hex(bad));
718 printf(_("We cannot bisect more!\n"));
719
720 return BISECT_ONLY_SKIPPED_LEFT;
721}
722
723static int is_expected_rev(const struct object_id *oid)
724{
725 struct object_id expected_oid;
726 if (refs_read_ref(get_main_ref_store(the_repository), "BISECT_EXPECTED_REV", &expected_oid))
727 return 0;
728 return oideq(oid, &expected_oid);
729}
730
731enum bisect_error bisect_checkout(const struct object_id *bisect_rev,
732 int no_checkout)
733{
734 struct commit *commit;
735 struct pretty_print_context pp = {0};
736 struct strbuf commit_msg = STRBUF_INIT;
737
738 refs_update_ref(get_main_ref_store(the_repository), NULL,
739 "BISECT_EXPECTED_REV", bisect_rev, NULL, 0,
740 UPDATE_REFS_DIE_ON_ERR);
741
742 if (no_checkout) {
743 refs_update_ref(get_main_ref_store(the_repository), NULL,
744 "BISECT_HEAD", bisect_rev, NULL, 0,
745 UPDATE_REFS_DIE_ON_ERR);
746 } else {
747 struct child_process cmd = CHILD_PROCESS_INIT;
748
749 cmd.git_cmd = 1;
750 strvec_pushl(&cmd.args, "checkout", "-q",
751 oid_to_hex(bisect_rev), "--", NULL);
752 if (run_command(&cmd))
753 /*
754 * Errors in `run_command()` itself, signaled by res < 0,
755 * and errors in the child process, signaled by res > 0
756 * can both be treated as regular BISECT_FAILED (-1).
757 */
758 return BISECT_FAILED;
759 }
760
761 commit = lookup_commit_reference(the_repository, bisect_rev);
762 repo_format_commit_message(the_repository, commit, "[%H] %s%n",
763 &commit_msg, &pp);
764 fputs(commit_msg.buf, stdout);
765 strbuf_release(&commit_msg);
766
767 return BISECT_OK;
768}
769
770static struct commit *get_commit_reference(struct repository *r,
771 const struct object_id *oid)
772{
773 struct commit *c = lookup_commit_reference(r, oid);
774 if (!c)
775 die(_("Not a valid commit name %s"), oid_to_hex(oid));
776 return c;
777}
778
779static struct commit **get_bad_and_good_commits(struct repository *r,
780 size_t *rev_nr)
781{
782 struct commit **rev;
783 size_t i, n = 0;
784
785 ALLOC_ARRAY(rev, 1 + good_revs.nr);
786 rev[n++] = get_commit_reference(r, current_bad_oid);
787 for (i = 0; i < good_revs.nr; i++)
788 rev[n++] = get_commit_reference(r, good_revs.oid + i);
789 *rev_nr = n;
790
791 return rev;
792}
793
794static enum bisect_error handle_bad_merge_base(void)
795{
796 if (is_expected_rev(current_bad_oid)) {
797 char *bad_hex = oid_to_hex(current_bad_oid);
798 char *good_hex = join_oid_array_hex(&good_revs, ' ');
799 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
800 fprintf(stderr, _("The merge base %s is bad.\n"
801 "This means the bug has been fixed "
802 "between %s and [%s].\n"),
803 bad_hex, bad_hex, good_hex);
804 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
805 fprintf(stderr, _("The merge base %s is new.\n"
806 "The property has changed "
807 "between %s and [%s].\n"),
808 bad_hex, bad_hex, good_hex);
809 } else {
810 fprintf(stderr, _("The merge base %s is %s.\n"
811 "This means the first '%s' commit is "
812 "between %s and [%s].\n"),
813 bad_hex, term_bad, term_good, bad_hex, good_hex);
814 }
815
816 free(good_hex);
817 return BISECT_MERGE_BASE_CHECK;
818 }
819
820 fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
821 "git bisect cannot work properly in this case.\n"
822 "Maybe you mistook %s and %s revs?\n"),
823 term_good, term_bad, term_good, term_bad);
824 return BISECT_FAILED;
825}
826
827static void handle_skipped_merge_base(const struct object_id *mb)
828{
829 char *mb_hex = oid_to_hex(mb);
830 char *bad_hex = oid_to_hex(current_bad_oid);
831 char *good_hex = join_oid_array_hex(&good_revs, ' ');
832
833 warning(_("the merge base between %s and [%s] "
834 "must be skipped.\n"
835 "So we cannot be sure the first %s commit is "
836 "between %s and %s.\n"
837 "We continue anyway."),
838 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
839 free(good_hex);
840}
841
842/*
843 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
844 *
845 * - If one is "bad" (or "new"), it means the user assumed something wrong
846 * and we must return error with a non 0 error code.
847 * - If one is "good" (or "old"), that's good, we have nothing to do.
848 * - If one is "skipped", we can't know but we should warn.
849 * - If we don't know, we should check it out and ask the user to test.
850 * - If a merge base must be tested, on success return
851 * BISECT_INTERNAL_SUCCESS_MERGE_BASE (-11) a special condition
852 * for early success, this will be converted back to 0 in
853 * check_good_are_ancestors_of_bad().
854 */
855static enum bisect_error check_merge_bases(size_t rev_nr, struct commit **rev, int no_checkout)
856{
857 enum bisect_error res = BISECT_OK;
858 struct commit_list *result = NULL;
859
860 if (repo_get_merge_bases_many(the_repository, rev[0], rev_nr - 1,
861 rev + 1, &result) < 0)
862 exit(128);
863
864 for (struct commit_list *l = result; l; l = l->next) {
865 const struct object_id *mb = &l->item->object.oid;
866 if (oideq(mb, current_bad_oid)) {
867 res = handle_bad_merge_base();
868 break;
869 } else if (0 <= oid_array_lookup(&good_revs, mb)) {
870 continue;
871 } else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
872 handle_skipped_merge_base(mb);
873 } else {
874 printf(_("Bisecting: a merge base must be tested\n"));
875 res = bisect_checkout(mb, no_checkout);
876 if (!res)
877 /* indicate early success */
878 res = BISECT_INTERNAL_SUCCESS_MERGE_BASE;
879 break;
880 }
881 }
882
883 free_commit_list(result);
884 return res;
885}
886
887static int check_ancestors(struct repository *r, size_t rev_nr,
888 struct commit **rev, const char *prefix)
889{
890 struct strvec rev_argv = STRVEC_INIT;
891 struct rev_info revs;
892 int res;
893
894 bisect_rev_setup(r, &revs, &rev_argv, prefix, "^%s", "%s", 0);
895
896 bisect_common(&revs);
897 res = (revs.commits != NULL);
898
899 /* Clean up objects used, as they will be reused. */
900 clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
901
902 release_revisions(&revs);
903 strvec_clear(&rev_argv);
904 return res;
905}
906
907/*
908 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
909 * ancestor of the "bad" rev.
910 *
911 * If that's not the case, we need to check the merge bases.
912 * If a merge base must be tested by the user, its source code will be
913 * checked out to be tested by the user and we will return.
914 */
915
916static enum bisect_error check_good_are_ancestors_of_bad(struct repository *r,
917 const char *prefix,
918 int no_checkout)
919{
920 char *filename;
921 struct stat st;
922 int fd;
923 size_t rev_nr;
924 enum bisect_error res = BISECT_OK;
925 struct commit **rev;
926
927 if (!current_bad_oid)
928 return error(_("a %s revision is needed"), term_bad);
929
930 filename = repo_git_path(the_repository, "BISECT_ANCESTORS_OK");
931
932 /* Check if file BISECT_ANCESTORS_OK exists. */
933 if (!stat(filename, &st) && S_ISREG(st.st_mode))
934 goto done;
935
936 /* Bisecting with no good rev is ok. */
937 if (!good_revs.nr)
938 goto done;
939
940 /* Check if all good revs are ancestor of the bad rev. */
941
942 rev = get_bad_and_good_commits(r, &rev_nr);
943 if (check_ancestors(r, rev_nr, rev, prefix))
944 res = check_merge_bases(rev_nr, rev, no_checkout);
945 free(rev);
946
947 if (!res) {
948 /* Create file BISECT_ANCESTORS_OK. */
949 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
950 if (fd < 0)
951 /*
952 * BISECT_ANCESTORS_OK file is not absolutely necessary,
953 * the bisection process will continue at the next
954 * bisection step.
955 * So, just signal with a warning that something
956 * might be wrong.
957 */
958 warning_errno(_("could not create file '%s'"),
959 filename);
960 else
961 close(fd);
962 }
963 done:
964 free(filename);
965 return res;
966}
967
968/*
969 * Display a commit summary to the user.
970 */
971static void show_commit(struct commit *commit)
972{
973 struct child_process show = CHILD_PROCESS_INIT;
974
975 /*
976 * Call git show with --no-pager, as it would otherwise
977 * paginate the "git show" output only, not the output
978 * from bisect_next_all(); this can be fixed by moving
979 * it into a --format parameter, but that would override
980 * the user's default options for "git show", which we
981 * are trying to honour.
982 */
983 strvec_pushl(&show.args,
984 "--no-pager",
985 "show",
986 "--stat",
987 "--summary",
988 "--no-abbrev-commit",
989 "--diff-merges=first-parent",
990 oid_to_hex(&commit->object.oid), NULL);
991 show.git_cmd = 1;
992 if (run_command(&show))
993 die(_("unable to start 'show' for object '%s'"),
994 oid_to_hex(&commit->object.oid));
995}
996
997/*
998 * The terms used for this bisect session are stored in BISECT_TERMS.
999 * We read them and store them to adapt the messages accordingly.
1000 * Default is bad/good.
1001 */
1002void read_bisect_terms(char **read_bad, char **read_good)
1003{
1004 struct strbuf str = STRBUF_INIT;
1005 const char *filename = git_path_bisect_terms();
1006 FILE *fp = fopen(filename, "r");
1007
1008 if (!fp) {
1009 if (errno == ENOENT) {
1010 free(*read_bad);
1011 *read_bad = xstrdup("bad");
1012 free(*read_good);
1013 *read_good = xstrdup("good");
1014 return;
1015 } else {
1016 die_errno(_("could not read file '%s'"), filename);
1017 }
1018 } else {
1019 strbuf_getline_lf(&str, fp);
1020 free(*read_bad);
1021 *read_bad = strbuf_detach(&str, NULL);
1022 strbuf_getline_lf(&str, fp);
1023 free(*read_good);
1024 *read_good = strbuf_detach(&str, NULL);
1025 }
1026 strbuf_release(&str);
1027 fclose(fp);
1028}
1029
1030/*
1031 * We use the convention that return BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10) means
1032 * the bisection process finished successfully.
1033 * In this case the calling function or command should not turn a
1034 * BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND return code into an error or a non zero exit code.
1035 *
1036 * Checking BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND
1037 * in bisect_helper::bisect_next() and only transforming it to 0 at
1038 * the end of bisect_helper::cmd_bisect__helper() helps bypassing
1039 * all the code related to finding a commit to test.
1040 */
1041enum bisect_error bisect_next_all(struct repository *r, const char *prefix)
1042{
1043 struct strvec rev_argv = STRVEC_INIT;
1044 struct rev_info revs = REV_INFO_INIT;
1045 struct commit_list *tried = NULL;
1046 int reaches = 0, all = 0, nr, steps;
1047 enum bisect_error res = BISECT_OK;
1048 struct object_id *bisect_rev;
1049 char *steps_msg;
1050 /*
1051 * If no_checkout is non-zero, the bisection process does not
1052 * checkout the trial commit but instead simply updates BISECT_HEAD.
1053 */
1054 int no_checkout = refs_ref_exists(get_main_ref_store(the_repository),
1055 "BISECT_HEAD");
1056 unsigned bisect_flags = 0;
1057
1058 read_bisect_terms(&term_bad, &term_good);
1059 if (read_bisect_refs())
1060 die(_("reading bisect refs failed"));
1061
1062 if (file_exists(git_path_bisect_first_parent()))
1063 bisect_flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
1064
1065 if (skipped_revs.nr)
1066 bisect_flags |= FIND_BISECTION_ALL;
1067
1068 res = check_good_are_ancestors_of_bad(r, prefix, no_checkout);
1069 if (res)
1070 goto cleanup;
1071
1072 bisect_rev_setup(r, &revs, &rev_argv, prefix, "%s", "^%s", 1);
1073
1074 revs.first_parent_only = !!(bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY);
1075 revs.limited = 1;
1076
1077 bisect_common(&revs);
1078
1079 find_bisection(&revs.commits, &reaches, &all, bisect_flags);
1080 revs.commits = managed_skipped(revs.commits, &tried);
1081
1082 if (!revs.commits) {
1083 /*
1084 * We should return error here only if the "bad"
1085 * commit is also a "skip" commit.
1086 */
1087 res = error_if_skipped_commits(tried, NULL);
1088 if (res < 0)
1089 goto cleanup;
1090 printf(_("%s was both %s and %s\n"),
1091 oid_to_hex(current_bad_oid),
1092 term_good,
1093 term_bad);
1094
1095 res = BISECT_FAILED;
1096 goto cleanup;
1097 }
1098
1099 if (!all) {
1100 fprintf(stderr, _("No testable commit found.\n"
1101 "Maybe you started with bad path arguments?\n"));
1102
1103 res = BISECT_NO_TESTABLE_COMMIT;
1104 goto cleanup;
1105 }
1106
1107 bisect_rev = &revs.commits->item->object.oid;
1108
1109 if (oideq(bisect_rev, current_bad_oid)) {
1110 res = error_if_skipped_commits(tried, current_bad_oid);
1111 if (res)
1112 goto cleanup;
1113 printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
1114 term_bad);
1115
1116 show_commit(revs.commits->item);
1117 /*
1118 * This means the bisection process succeeded.
1119 * Using BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10)
1120 * so that the call chain can simply check
1121 * for negative return values for early returns up
1122 * until the cmd_bisect__helper() caller.
1123 */
1124 res = BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
1125 goto cleanup;
1126 }
1127
1128 nr = all - reaches - 1;
1129 steps = estimate_bisect_steps(all);
1130
1131 steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
1132 steps), steps);
1133 /*
1134 * TRANSLATORS: the last %s will be replaced with "(roughly %d
1135 * steps)" translation.
1136 */
1137 printf(Q_("Bisecting: %d revision left to test after this %s\n",
1138 "Bisecting: %d revisions left to test after this %s\n",
1139 nr), nr, steps_msg);
1140 free(steps_msg);
1141 /* Clean up objects used, as they will be reused. */
1142 repo_clear_commit_marks(r, ALL_REV_FLAGS);
1143
1144 res = bisect_checkout(bisect_rev, no_checkout);
1145cleanup:
1146 free_commit_list(tried);
1147 release_revisions(&revs);
1148 strvec_clear(&rev_argv);
1149 return res;
1150}
1151
1152static inline int exp2i(int n)
1153{
1154 return 1 << n;
1155}
1156
1157/*
1158 * Estimate the number of bisect steps left (after the current step)
1159 *
1160 * For any x between 0 included and 2^n excluded, the probability for
1161 * n - 1 steps left looks like:
1162 *
1163 * P(2^n + x) == (2^n - x) / (2^n + x)
1164 *
1165 * and P(2^n + x) < 0.5 means 2^n < 3x
1166 */
1167int estimate_bisect_steps(int all)
1168{
1169 int n, x, e;
1170
1171 if (all < 3)
1172 return 0;
1173
1174 n = log2u(all);
1175 e = exp2i(n);
1176 x = all - e;
1177
1178 return (e < 3 * x) ? n : n - 1;
1179}
1180
1181static int mark_for_removal(const char *refname,
1182 const char *referent UNUSED,
1183 const struct object_id *oid UNUSED,
1184 int flag UNUSED, void *cb_data)
1185{
1186 struct string_list *refs = cb_data;
1187 char *ref = xstrfmt("refs/bisect%s", refname);
1188 string_list_append(refs, ref);
1189 return 0;
1190}
1191
1192int bisect_clean_state(void)
1193{
1194 int result = 0;
1195
1196 /* There may be some refs packed during bisection */
1197 struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
1198 refs_for_each_ref_in(get_main_ref_store(the_repository),
1199 "refs/bisect", mark_for_removal,
1200 (void *) &refs_for_removal);
1201 string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
1202 string_list_append(&refs_for_removal, xstrdup("BISECT_EXPECTED_REV"));
1203 result = refs_delete_refs(get_main_ref_store(the_repository),
1204 "bisect: remove", &refs_for_removal,
1205 REF_NO_DEREF);
1206 refs_for_removal.strdup_strings = 1;
1207 string_list_clear(&refs_for_removal, 0);
1208 unlink_or_warn(git_path_bisect_ancestors_ok());
1209 unlink_or_warn(git_path_bisect_log());
1210 unlink_or_warn(git_path_bisect_names());
1211 unlink_or_warn(git_path_bisect_run());
1212 unlink_or_warn(git_path_bisect_terms());
1213 unlink_or_warn(git_path_bisect_first_parent());
1214 /*
1215 * Cleanup BISECT_START last to support the --no-checkout option
1216 * introduced in the commit 4796e823a.
1217 */
1218 unlink_or_warn(git_path_bisect_start());
1219
1220 return result;
1221}