Merge branch 'rs/nth-switch-code-simplification'
[git/git.git] / bisect.c
CommitLineData
a2ad79ce 1#include "cache.h"
b2141fc1 2#include "config.h"
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CC
3#include "commit.h"
4#include "diff.h"
5#include "revision.h"
1bf072e3
CC
6#include "refs.h"
7#include "list-objects.h"
3b437b0d 8#include "quote.h"
4eb5b646 9#include "sha1-lookup.h"
ef24c7ca 10#include "run-command.h"
e22278c0 11#include "log-tree.h"
a2ad79ce 12#include "bisect.h"
902bb364 13#include "sha1-array.h"
8a534b61 14#include "argv-array.h"
bb408ac9 15#include "commit-slab.h"
64043556 16#include "commit-reach.h"
b0eb92bb 17#include "object-store.h"
6212b1aa 18
910650d2 19static struct oid_array good_revs;
20static struct oid_array skipped_revs;
1bf072e3 21
3c5ff995 22static struct object_id *current_bad_oid;
ef24c7ca 23
ef24c7ca
CC
24static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
25static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
26
43f9d9f3
AD
27static const char *term_bad;
28static const char *term_good;
29
208acbfb 30/* Remember to update object flag allocation in object.h */
a2ad79ce
CC
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 */
40static 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
67static 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
bb408ac9
NTND
76define_commit_slab(commit_weight, int *);
77static struct commit_weight commit_weight;
78
a2ad79ce
CC
79#define DEBUG_BISECT 0
80
81static inline int weight(struct commit_list *elem)
82{
bb408ac9 83 return **commit_weight_at(&commit_weight, elem->item);
a2ad79ce
CC
84}
85
86static inline void weight_set(struct commit_list *elem, int weight)
87{
bb408ac9 88 **commit_weight_at(&commit_weight, elem->item) = weight;
a2ad79ce
CC
89}
90
91static int count_interesting_parents(struct commit *commit)
92{
93 struct commit_list *p;
94 int count;
95
96 for (count = 0, p = commit->parents; p; p = p->next) {
97 if (p->item->object.flags & UNINTERESTING)
98 continue;
99 count++;
100 }
101 return count;
102}
103
104static inline int halfway(struct commit_list *p, int nr)
105{
106 /*
107 * Don't short-cut something we are not going to return!
108 */
109 if (p->item->object.flags & TREESAME)
110 return 0;
111 if (DEBUG_BISECT)
112 return 0;
113 /*
114 * 2 and 3 are halfway of 5.
115 * 3 is halfway of 6 but 2 and 4 are not.
116 */
117 switch (2 * weight(p) - nr) {
118 case -1: case 0: case 1:
119 return 1;
120 default:
121 return 0;
122 }
123}
124
a2ad79ce
CC
125static void show_list(const char *debug, int counted, int nr,
126 struct commit_list *list)
127{
128 struct commit_list *p;
129
b0eb92bb
NTND
130 if (!DEBUG_BISECT)
131 return;
132
a2ad79ce
CC
133 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
134
135 for (p = list; p; p = p->next) {
136 struct commit_list *pp;
137 struct commit *commit = p->item;
138 unsigned flags = commit->object.flags;
139 enum object_type type;
140 unsigned long size;
b4f5aca4 141 char *buf = read_object_file(&commit->object.oid, &type,
142 &size);
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CC
143 const char *subject_start;
144 int subject_len;
a2ad79ce
CC
145
146 fprintf(stderr, "%c%c%c ",
147 (flags & TREESAME) ? ' ' : 'T',
148 (flags & UNINTERESTING) ? 'U' : ' ',
149 (flags & COUNTED) ? 'C' : ' ');
b0eb92bb 150 if (*commit_weight_at(&commit_weight, p->item))
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CC
151 fprintf(stderr, "%3d", weight(p));
152 else
153 fprintf(stderr, "---");
14ced556 154 fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
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CC
155 for (pp = commit->parents; pp; pp = pp->next)
156 fprintf(stderr, " %.*s", 8,
14ced556 157 oid_to_hex(&pp->item->object.oid));
a2ad79ce 158
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CC
159 subject_len = find_commit_subject(buf, &subject_start);
160 if (subject_len)
161 fprintf(stderr, " %.*s", subject_len, subject_start);
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CC
162 fprintf(stderr, "\n");
163 }
164}
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CC
165
166static struct commit_list *best_bisection(struct commit_list *list, int nr)
167{
168 struct commit_list *p, *best;
169 int best_distance = -1;
170
171 best = list;
172 for (p = list; p; p = p->next) {
173 int distance;
174 unsigned flags = p->item->object.flags;
175
176 if (flags & TREESAME)
177 continue;
178 distance = weight(p);
179 if (nr - distance < distance)
180 distance = nr - distance;
181 if (distance > best_distance) {
182 best = p;
183 best_distance = distance;
184 }
185 }
186
187 return best;
188}
189
190struct commit_dist {
191 struct commit *commit;
192 int distance;
193};
194
195static int compare_commit_dist(const void *a_, const void *b_)
196{
197 struct commit_dist *a, *b;
198
199 a = (struct commit_dist *)a_;
200 b = (struct commit_dist *)b_;
201 if (a->distance != b->distance)
202 return b->distance - a->distance; /* desc sort */
f2fd0760 203 return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
a2ad79ce
CC
204}
205
206static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
207{
208 struct commit_list *p;
209 struct commit_dist *array = xcalloc(nr, sizeof(*array));
5b1ef2ce 210 struct strbuf buf = STRBUF_INIT;
a2ad79ce
CC
211 int cnt, i;
212
213 for (p = list, cnt = 0; p; p = p->next) {
214 int distance;
215 unsigned flags = p->item->object.flags;
216
217 if (flags & TREESAME)
218 continue;
219 distance = weight(p);
220 if (nr - distance < distance)
221 distance = nr - distance;
222 array[cnt].commit = p->item;
223 array[cnt].distance = distance;
224 cnt++;
225 }
9ed0d8d6 226 QSORT(array, cnt, compare_commit_dist);
a2ad79ce 227 for (p = list, i = 0; i < cnt; i++) {
a2ad79ce
CC
228 struct object *obj = &(array[i].commit->object);
229
5b1ef2ce
JK
230 strbuf_reset(&buf);
231 strbuf_addf(&buf, "dist=%d", array[i].distance);
232 add_name_decoration(DECORATION_NONE, buf.buf, obj);
662174d2 233
a2ad79ce 234 p->item = array[i].commit;
7c117184
235 if (i < cnt - 1)
236 p = p->next;
a2ad79ce 237 }
2e9fdc79
ÆAB
238 if (p) {
239 free_commit_list(p->next);
240 p->next = NULL;
241 }
5b1ef2ce 242 strbuf_release(&buf);
a2ad79ce
CC
243 free(array);
244 return list;
245}
246
247/*
248 * zero or positive weight is the number of interesting commits it can
249 * reach, including itself. Especially, weight = 0 means it does not
250 * reach any tree-changing commits (e.g. just above uninteresting one
251 * but traversal is with pathspec).
252 *
253 * weight = -1 means it has one parent and its distance is yet to
254 * be computed.
255 *
256 * weight = -2 means it has more than one parent and its distance is
257 * unknown. After running count_distance() first, they will get zero
258 * or positive distance.
259 */
260static struct commit_list *do_find_bisection(struct commit_list *list,
261 int nr, int *weights,
262 int find_all)
263{
264 int n, counted;
265 struct commit_list *p;
266
267 counted = 0;
268
269 for (n = 0, p = list; p; p = p->next) {
270 struct commit *commit = p->item;
271 unsigned flags = commit->object.flags;
272
bb408ac9 273 *commit_weight_at(&commit_weight, p->item) = &weights[n++];
a2ad79ce
CC
274 switch (count_interesting_parents(commit)) {
275 case 0:
276 if (!(flags & TREESAME)) {
277 weight_set(p, 1);
278 counted++;
279 show_list("bisection 2 count one",
280 counted, nr, list);
281 }
282 /*
283 * otherwise, it is known not to reach any
284 * tree-changing commit and gets weight 0.
285 */
286 break;
287 case 1:
288 weight_set(p, -1);
289 break;
290 default:
291 weight_set(p, -2);
292 break;
293 }
294 }
295
296 show_list("bisection 2 initialize", counted, nr, list);
297
298 /*
299 * If you have only one parent in the resulting set
300 * then you can reach one commit more than that parent
301 * can reach. So we do not have to run the expensive
302 * count_distance() for single strand of pearls.
303 *
304 * However, if you have more than one parents, you cannot
305 * just add their distance and one for yourself, since
306 * they usually reach the same ancestor and you would
307 * end up counting them twice that way.
308 *
309 * So we will first count distance of merges the usual
310 * way, and then fill the blanks using cheaper algorithm.
311 */
312 for (p = list; p; p = p->next) {
313 if (p->item->object.flags & UNINTERESTING)
314 continue;
315 if (weight(p) != -2)
316 continue;
317 weight_set(p, count_distance(p));
318 clear_distance(list);
319
320 /* Does it happen to be at exactly half-way? */
321 if (!find_all && halfway(p, nr))
322 return p;
323 counted++;
324 }
325
326 show_list("bisection 2 count_distance", counted, nr, list);
327
328 while (counted < nr) {
329 for (p = list; p; p = p->next) {
330 struct commit_list *q;
331 unsigned flags = p->item->object.flags;
332
333 if (0 <= weight(p))
334 continue;
335 for (q = p->item->parents; q; q = q->next) {
336 if (q->item->object.flags & UNINTERESTING)
337 continue;
338 if (0 <= weight(q))
339 break;
340 }
341 if (!q)
342 continue;
343
344 /*
345 * weight for p is unknown but q is known.
346 * add one for p itself if p is to be counted,
347 * otherwise inherit it from q directly.
348 */
349 if (!(flags & TREESAME)) {
350 weight_set(p, weight(q)+1);
351 counted++;
352 show_list("bisection 2 count one",
353 counted, nr, list);
354 }
355 else
356 weight_set(p, weight(q));
357
358 /* Does it happen to be at exactly half-way? */
359 if (!find_all && halfway(p, nr))
360 return p;
361 }
362 }
363
364 show_list("bisection 2 counted all", counted, nr, list);
365
366 if (!find_all)
367 return best_bisection(list, nr);
368 else
369 return best_bisection_sorted(list, nr);
370}
371
24d707f6
372void find_bisection(struct commit_list **commit_list, int *reaches,
373 int *all, int find_all)
a2ad79ce
CC
374{
375 int nr, on_list;
24d707f6 376 struct commit_list *list, *p, *best, *next, *last;
a2ad79ce
CC
377 int *weights;
378
24d707f6 379 show_list("bisection 2 entry", 0, 0, *commit_list);
bb408ac9 380 init_commit_weight(&commit_weight);
a2ad79ce
CC
381
382 /*
383 * Count the number of total and tree-changing items on the
384 * list, while reversing the list.
385 */
24d707f6 386 for (nr = on_list = 0, last = NULL, p = *commit_list;
a2ad79ce
CC
387 p;
388 p = next) {
389 unsigned flags = p->item->object.flags;
390
391 next = p->next;
fc5c40bb
392 if (flags & UNINTERESTING) {
393 free(p);
a2ad79ce 394 continue;
fc5c40bb 395 }
a2ad79ce
CC
396 p->next = last;
397 last = p;
398 if (!(flags & TREESAME))
399 nr++;
400 on_list++;
401 }
402 list = last;
403 show_list("bisection 2 sorted", 0, nr, list);
404
405 *all = nr;
406 weights = xcalloc(on_list, sizeof(*weights));
407
408 /* Do the real work of finding bisection commit. */
409 best = do_find_bisection(list, nr, weights, find_all);
410 if (best) {
f4e45cb3
411 if (!find_all) {
412 list->item = best->item;
413 free_commit_list(list->next);
414 best = list;
a2ad79ce 415 best->next = NULL;
f4e45cb3 416 }
a2ad79ce
CC
417 *reaches = weight(best);
418 }
419 free(weights);
24d707f6 420 *commit_list = best;
bb408ac9 421 clear_commit_weight(&commit_weight);
a2ad79ce
CC
422}
423
eed25148 424static int register_ref(const char *refname, const struct object_id *oid,
1bf072e3
CC
425 int flags, void *cb_data)
426{
43f9d9f3
AD
427 struct strbuf good_prefix = STRBUF_INIT;
428 strbuf_addstr(&good_prefix, term_good);
429 strbuf_addstr(&good_prefix, "-");
430
431 if (!strcmp(refname, term_bad)) {
3c5ff995 432 current_bad_oid = xmalloc(sizeof(*current_bad_oid));
eed25148 433 oidcpy(current_bad_oid, oid);
43f9d9f3 434 } else if (starts_with(refname, good_prefix.buf)) {
910650d2 435 oid_array_append(&good_revs, oid);
59556548 436 } else if (starts_with(refname, "skip-")) {
910650d2 437 oid_array_append(&skipped_revs, oid);
1bf072e3
CC
438 }
439
43f9d9f3
AD
440 strbuf_release(&good_prefix);
441
1bf072e3
CC
442 return 0;
443}
444
445static int read_bisect_refs(void)
446{
eed25148 447 return for_each_ref_in("refs/bisect/", register_ref, NULL);
1bf072e3
CC
448}
449
f932729c
JK
450static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
451static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
fb71a329
PB
452static GIT_PATH_FUNC(git_path_bisect_ancestors_ok, "BISECT_ANCESTORS_OK")
453static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
454static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
455static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
f5d284f6 456static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
fb71a329 457static GIT_PATH_FUNC(git_path_head_name, "head-name")
f932729c 458
2af202be 459static void read_bisect_paths(struct argv_array *array)
3b437b0d
CC
460{
461 struct strbuf str = STRBUF_INIT;
f932729c 462 const char *filename = git_path_bisect_names();
23a9e071 463 FILE *fp = xfopen(filename, "r");
3b437b0d 464
8f309aeb 465 while (strbuf_getline_lf(&str, fp) != EOF) {
3b437b0d 466 strbuf_trim(&str);
8a534b61 467 if (sq_dequote_to_argv_array(str.buf, array))
14dc4899 468 die(_("Badly quoted content in file '%s': %s"),
8a534b61 469 filename, str.buf);
3b437b0d
CC
470 }
471
472 strbuf_release(&str);
473 fclose(fp);
474}
475
910650d2 476static char *join_sha1_array_hex(struct oid_array *array, char delim)
c0537662
CC
477{
478 struct strbuf joined_hexs = STRBUF_INIT;
479 int i;
480
902bb364 481 for (i = 0; i < array->nr; i++) {
ee3051bd 482 strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
902bb364 483 if (i + 1 < array->nr)
c0537662
CC
484 strbuf_addch(&joined_hexs, delim);
485 }
486
487 return strbuf_detach(&joined_hexs, NULL);
488}
489
9af3589e
CC
490/*
491 * In this function, passing a not NULL skipped_first is very special.
492 * It means that we want to know if the first commit in the list is
493 * skipped because we will want to test a commit away from it if it is
494 * indeed skipped.
495 * So if the first commit is skipped, we cannot take the shortcut to
496 * just "return list" when we find the first non skipped commit, we
497 * have to return a fully filtered list.
498 *
499 * We use (*skipped_first == -1) to mean "it has been found that the
500 * first commit is not skipped". In this case *skipped_first is set back
501 * to 0 just before the function returns.
502 */
95188648
CC
503struct commit_list *filter_skipped(struct commit_list *list,
504 struct commit_list **tried,
9af3589e
CC
505 int show_all,
506 int *count,
507 int *skipped_first)
95188648
CC
508{
509 struct commit_list *filtered = NULL, **f = &filtered;
510
511 *tried = NULL;
512
9af3589e
CC
513 if (skipped_first)
514 *skipped_first = 0;
515 if (count)
516 *count = 0;
517
902bb364 518 if (!skipped_revs.nr)
95188648
CC
519 return list;
520
95188648
CC
521 while (list) {
522 struct commit_list *next = list->next;
523 list->next = NULL;
910650d2 524 if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
9af3589e
CC
525 if (skipped_first && !*skipped_first)
526 *skipped_first = 1;
95188648
CC
527 /* Move current to tried list */
528 *tried = list;
529 tried = &list->next;
530 } else {
9af3589e
CC
531 if (!show_all) {
532 if (!skipped_first || !*skipped_first)
533 return list;
534 } else if (skipped_first && !*skipped_first) {
535 /* This means we know it's not skipped */
536 *skipped_first = -1;
537 }
95188648
CC
538 /* Move current to filtered list */
539 *f = list;
540 f = &list->next;
9af3589e
CC
541 if (count)
542 (*count)++;
95188648
CC
543 }
544 list = next;
545 }
546
9af3589e
CC
547 if (skipped_first && *skipped_first == -1)
548 *skipped_first = 0;
549
95188648
CC
550 return filtered;
551}
1bf072e3 552
ebc9529f
CC
553#define PRN_MODULO 32768
554
555/*
556 * This is a pseudo random number generator based on "man 3 rand".
557 * It is not used properly because the seed is the argument and it
558 * is increased by one between each call, but that should not matter
559 * for this application.
560 */
3b335762
NTND
561static unsigned get_prn(unsigned count)
562{
ebc9529f 563 count = count * 1103515245 + 12345;
7b96d888 564 return (count/65536) % PRN_MODULO;
ebc9529f
CC
565}
566
567/*
568 * Custom integer square root from
5e68729f 569 * https://en.wikipedia.org/wiki/Integer_square_root
ebc9529f
CC
570 */
571static int sqrti(int val)
572{
573 float d, x = val;
574
575 if (val == 0)
576 return 0;
577
578 do {
579 float y = (x + (float)val / x) / 2;
580 d = (y > x) ? y - x : x - y;
581 x = y;
582 } while (d >= 0.5);
583
584 return (int)x;
585}
586
587static struct commit_list *skip_away(struct commit_list *list, int count)
62d0b0da 588{
62d0b0da 589 struct commit_list *cur, *previous;
ebc9529f
CC
590 int prn, index, i;
591
592 prn = get_prn(count);
593 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
62d0b0da
CC
594
595 cur = list;
596 previous = NULL;
62d0b0da
CC
597
598 for (i = 0; cur; cur = cur->next, i++) {
599 if (i == index) {
9001dc2a 600 if (!oideq(&cur->item->object.oid, current_bad_oid))
62d0b0da
CC
601 return cur;
602 if (previous)
603 return previous;
604 return list;
605 }
606 previous = cur;
607 }
608
609 return list;
610}
611
612static struct commit_list *managed_skipped(struct commit_list *list,
613 struct commit_list **tried)
614{
615 int count, skipped_first;
62d0b0da
CC
616
617 *tried = NULL;
618
902bb364 619 if (!skipped_revs.nr)
62d0b0da
CC
620 return list;
621
622 list = filter_skipped(list, tried, 0, &count, &skipped_first);
623
624 if (!skipped_first)
625 return list;
626
ebc9529f 627 return skip_away(list, count);
62d0b0da
CC
628}
629
69d2cfe6
NTND
630static void bisect_rev_setup(struct repository *r, struct rev_info *revs,
631 const char *prefix,
a22347c6
CC
632 const char *bad_format, const char *good_format,
633 int read_paths)
1bf072e3 634{
8a534b61 635 struct argv_array rev_argv = ARGV_ARRAY_INIT;
fad2d31d
CC
636 int i;
637
69d2cfe6 638 repo_init_revisions(r, revs, prefix);
3b437b0d
CC
639 revs->abbrev = 0;
640 revs->commit_format = CMIT_FMT_UNSPECIFIED;
1bf072e3 641
1c953a1f 642 /* rev_argv.argv[0] will be ignored by setup_revisions */
8a534b61 643 argv_array_push(&rev_argv, "bisect_rev_setup");
3c5ff995 644 argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
902bb364 645 for (i = 0; i < good_revs.nr; i++)
8a534b61 646 argv_array_pushf(&rev_argv, good_format,
ee3051bd 647 oid_to_hex(good_revs.oid + i));
8a534b61 648 argv_array_push(&rev_argv, "--");
a22347c6
CC
649 if (read_paths)
650 read_bisect_paths(&rev_argv);
3b437b0d 651
8a534b61
JK
652 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
653 /* XXX leak rev_argv, as "revs" may still be pointing to it */
3b437b0d
CC
654}
655
a22347c6 656static void bisect_common(struct rev_info *revs)
2ace9727 657{
2ace9727
CC
658 if (prepare_revision_walk(revs))
659 die("revision walk setup failed");
660 if (revs->tree_objects)
4f6d26b1 661 mark_edges_uninteresting(revs, NULL, 0);
2ace9727
CC
662}
663
ef24c7ca 664static void exit_if_skipped_commits(struct commit_list *tried,
3c5ff995 665 const struct object_id *bad)
ef24c7ca
CC
666{
667 if (!tried)
668 return;
669
670 printf("There are only 'skip'ped commits left to test.\n"
43f9d9f3 671 "The first %s commit could be any of:\n", term_bad);
54307ea7
JH
672
673 for ( ; tried; tried = tried->next)
674 printf("%s\n", oid_to_hex(&tried->item->object.oid));
675
ef24c7ca 676 if (bad)
3c5ff995 677 printf("%s\n", oid_to_hex(bad));
14dc4899 678 printf(_("We cannot bisect more!\n"));
ef24c7ca
CC
679 exit(2);
680}
681
3c5ff995 682static int is_expected_rev(const struct object_id *oid)
c0537662 683{
f932729c 684 const char *filename = git_path_bisect_expected_rev();
c0537662
CC
685 struct stat st;
686 struct strbuf str = STRBUF_INIT;
687 FILE *fp;
688 int res = 0;
689
690 if (stat(filename, &st) || !S_ISREG(st.st_mode))
691 return 0;
692
e9d983f1 693 fp = fopen_or_warn(filename, "r");
c0537662
CC
694 if (!fp)
695 return 0;
696
8f309aeb 697 if (strbuf_getline_lf(&str, fp) != EOF)
3c5ff995 698 res = !strcmp(str.buf, oid_to_hex(oid));
c0537662
CC
699
700 strbuf_release(&str);
701 fclose(fp);
702
703 return res;
704}
705
4be0deec 706static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
ef24c7ca 707{
dc01505f 708 char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
ef24c7ca 709
4be0deec 710 memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
ae077771 711 update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
ef24c7ca
CC
712
713 argv_checkout[2] = bisect_rev_hex;
fee92fc1 714 if (no_checkout) {
ae077771 715 update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
716 UPDATE_REFS_DIE_ON_ERR);
fee92fc1 717 } else {
4824d1b8 718 int res;
fee92fc1
JS
719 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
720 if (res)
721 exit(res);
722 }
ef24c7ca
CC
723
724 argv_show_branch[1] = bisect_rev_hex;
725 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
726}
727
69d2cfe6
NTND
728static struct commit *get_commit_reference(struct repository *r,
729 const struct object_id *oid)
c0537662 730{
69d2cfe6
NTND
731 struct commit *c = lookup_commit_reference(r, oid);
732 if (!c)
ee3051bd 733 die(_("Not a valid commit name %s"), oid_to_hex(oid));
69d2cfe6 734 return c;
c0537662
CC
735}
736
69d2cfe6
NTND
737static struct commit **get_bad_and_good_commits(struct repository *r,
738 int *rev_nr)
c0537662 739{
b32fa95f 740 struct commit **rev;
c0537662
CC
741 int i, n = 0;
742
b32fa95f 743 ALLOC_ARRAY(rev, 1 + good_revs.nr);
69d2cfe6 744 rev[n++] = get_commit_reference(r, current_bad_oid);
902bb364 745 for (i = 0; i < good_revs.nr; i++)
69d2cfe6 746 rev[n++] = get_commit_reference(r, good_revs.oid + i);
c0537662
CC
747 *rev_nr = n;
748
749 return rev;
750}
751
752static void handle_bad_merge_base(void)
753{
3c5ff995 754 if (is_expected_rev(current_bad_oid)) {
755 char *bad_hex = oid_to_hex(current_bad_oid);
c0537662 756 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
43f9d9f3 757 if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
14dc4899 758 fprintf(stderr, _("The merge base %s is bad.\n"
43f9d9f3 759 "This means the bug has been fixed "
14dc4899 760 "between %s and [%s].\n"),
43f9d9f3 761 bad_hex, bad_hex, good_hex);
21e5cfd8 762 } else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
14dc4899 763 fprintf(stderr, _("The merge base %s is new.\n"
21e5cfd8 764 "The property has changed "
14dc4899 765 "between %s and [%s].\n"),
21e5cfd8 766 bad_hex, bad_hex, good_hex);
43f9d9f3 767 } else {
14dc4899 768 fprintf(stderr, _("The merge base %s is %s.\n"
43f9d9f3 769 "This means the first '%s' commit is "
14dc4899 770 "between %s and [%s].\n"),
43f9d9f3
AD
771 bad_hex, term_bad, term_good, bad_hex, good_hex);
772 }
c0537662
CC
773 exit(3);
774 }
775
3f407b76 776 fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
c0537662 777 "git bisect cannot work properly in this case.\n"
14dc4899 778 "Maybe you mistook %s and %s revs?\n"),
43f9d9f3 779 term_good, term_bad, term_good, term_bad);
c0537662
CC
780 exit(1);
781}
782
4ce3621a 783static void handle_skipped_merge_base(const struct object_id *mb)
c0537662 784{
4ce3621a 785 char *mb_hex = oid_to_hex(mb);
c368dde9 786 char *bad_hex = oid_to_hex(current_bad_oid);
c0537662
CC
787 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
788
14dc4899 789 warning(_("the merge base between %s and [%s] "
c0537662 790 "must be skipped.\n"
43f9d9f3 791 "So we cannot be sure the first %s commit is "
c0537662 792 "between %s and %s.\n"
14dc4899 793 "We continue anyway."),
43f9d9f3 794 bad_hex, good_hex, term_bad, mb_hex, bad_hex);
c0537662
CC
795 free(good_hex);
796}
797
798/*
21e5cfd8 799 * "check_merge_bases" checks that merge bases are not "bad" (or "new").
c0537662 800 *
21e5cfd8 801 * - If one is "bad" (or "new"), it means the user assumed something wrong
c0537662 802 * and we must exit with a non 0 error code.
21e5cfd8 803 * - If one is "good" (or "old"), that's good, we have nothing to do.
c0537662
CC
804 * - If one is "skipped", we can't know but we should warn.
805 * - If we don't know, we should check it out and ask the user to test.
806 */
148f14ab 807static void check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
c0537662
CC
808{
809 struct commit_list *result;
c0537662 810
2ce406cc 811 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
c0537662
CC
812
813 for (; result; result = result->next) {
4ce3621a 814 const struct object_id *mb = &result->item->object.oid;
4a7e27e9 815 if (oideq(mb, current_bad_oid)) {
c0537662 816 handle_bad_merge_base();
910650d2 817 } else if (0 <= oid_array_lookup(&good_revs, mb)) {
c0537662 818 continue;
910650d2 819 } else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
c0537662
CC
820 handle_skipped_merge_base(mb);
821 } else {
14dc4899 822 printf(_("Bisecting: a merge base must be tested\n"));
4be0deec 823 exit(bisect_checkout(mb, no_checkout));
c0537662
CC
824 }
825 }
826
c0537662
CC
827 free_commit_list(result);
828}
829
69d2cfe6
NTND
830static int check_ancestors(struct repository *r, int rev_nr,
831 struct commit **rev, const char *prefix)
d937d4ac 832{
2d938fc7 833 struct rev_info revs;
86a0a408 834 int res;
d937d4ac 835
69d2cfe6 836 bisect_rev_setup(r, &revs, prefix, "^%s", "%s", 0);
d937d4ac 837
2d938fc7
CC
838 bisect_common(&revs);
839 res = (revs.commits != NULL);
840
841 /* Clean up objects used, as they will be reused. */
148f14ab 842 clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
d937d4ac 843
2d938fc7 844 return res;
d937d4ac
CC
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 */
69d2cfe6
NTND
855static void check_good_are_ancestors_of_bad(struct repository *r,
856 const char *prefix,
857 int no_checkout)
d937d4ac 858{
d292bfaf 859 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
d937d4ac 860 struct stat st;
148f14ab
RS
861 int fd, rev_nr;
862 struct commit **rev;
d937d4ac 863
3c5ff995 864 if (!current_bad_oid)
14dc4899 865 die(_("a %s revision is needed"), term_bad);
d937d4ac
CC
866
867 /* Check if file BISECT_ANCESTORS_OK exists. */
868 if (!stat(filename, &st) && S_ISREG(st.st_mode))
144e7090 869 goto done;
d937d4ac
CC
870
871 /* Bisecting with no good rev is ok. */
902bb364 872 if (good_revs.nr == 0)
144e7090 873 goto done;
d937d4ac 874
2d938fc7 875 /* Check if all good revs are ancestor of the bad rev. */
69d2cfe6
NTND
876 rev = get_bad_and_good_commits(r, &rev_nr);
877 if (check_ancestors(r, rev_nr, rev, prefix))
148f14ab
RS
878 check_merge_bases(rev_nr, rev, no_checkout);
879 free(rev);
d937d4ac
CC
880
881 /* Create file BISECT_ANCESTORS_OK. */
882 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
883 if (fd < 0)
14dc4899 884 warning_errno(_("could not create file '%s'"),
23e7a312 885 filename);
d937d4ac
CC
886 else
887 close(fd);
144e7090
MH
888 done:
889 free(filename);
d937d4ac
CC
890}
891
e22278c0
CC
892/*
893 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
894 */
69d2cfe6
NTND
895static void show_diff_tree(struct repository *r,
896 const char *prefix,
897 struct commit *commit)
e22278c0 898{
2008f290 899 const char *argv[] = {
b02be8b9 900 "diff-tree", "--pretty", "--stat", "--summary", "--cc", NULL
2008f290 901 };
e22278c0
CC
902 struct rev_info opt;
903
b02be8b9 904 git_config(git_diff_ui_config, NULL);
40ae3d3e 905 repo_init_revisions(r, &opt, prefix);
e22278c0 906
2008f290 907 setup_revisions(ARRAY_SIZE(argv) - 1, argv, &opt, NULL);
e22278c0
CC
908 log_tree_commit(&opt, commit);
909}
910
cb46d630
AD
911/*
912 * The terms used for this bisect session are stored in BISECT_TERMS.
913 * We read them and store them to adapt the messages accordingly.
914 * Default is bad/good.
915 */
916void read_bisect_terms(const char **read_bad, const char **read_good)
917{
918 struct strbuf str = STRBUF_INIT;
f5d284f6 919 const char *filename = git_path_bisect_terms();
cb46d630
AD
920 FILE *fp = fopen(filename, "r");
921
922 if (!fp) {
923 if (errno == ENOENT) {
924 *read_bad = "bad";
925 *read_good = "good";
926 return;
927 } else {
14dc4899 928 die_errno(_("could not read file '%s'"), filename);
cb46d630
AD
929 }
930 } else {
8f309aeb 931 strbuf_getline_lf(&str, fp);
cb46d630 932 *read_bad = strbuf_detach(&str, NULL);
8f309aeb 933 strbuf_getline_lf(&str, fp);
cb46d630
AD
934 *read_good = strbuf_detach(&str, NULL);
935 }
936 strbuf_release(&str);
937 fclose(fp);
938}
939
ef24c7ca
CC
940/*
941 * We use the convention that exiting with an exit code 10 means that
942 * the bisection process finished successfully.
943 * In this case the calling shell script should exit 0.
fee92fc1
JS
944 *
945 * If no_checkout is non-zero, the bisection process does not
946 * checkout the trial commit but instead simply updates BISECT_HEAD.
ef24c7ca 947 */
69d2cfe6 948int bisect_next_all(struct repository *r, const char *prefix, int no_checkout)
ef24c7ca
CC
949{
950 struct rev_info revs;
951 struct commit_list *tried;
6329bade 952 int reaches = 0, all = 0, nr, steps;
4be0deec 953 struct object_id *bisect_rev;
2cfa8357 954 char *steps_msg;
ef24c7ca 955
cb46d630 956 read_bisect_terms(&term_bad, &term_good);
2b020695 957 if (read_bisect_refs())
14dc4899 958 die(_("reading bisect refs failed"));
2b020695 959
69d2cfe6 960 check_good_are_ancestors_of_bad(r, prefix, no_checkout);
0871984d 961
69d2cfe6 962 bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
a22347c6 963 revs.limited = 1;
2b020695 964
a22347c6 965 bisect_common(&revs);
ef24c7ca 966
24d707f6 967 find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
62d0b0da 968 revs.commits = managed_skipped(revs.commits, &tried);
ef24c7ca
CC
969
970 if (!revs.commits) {
971 /*
972 * We should exit here only if the "bad"
973 * commit is also a "skip" commit.
974 */
975 exit_if_skipped_commits(tried, NULL);
976
14dc4899 977 printf(_("%s was both %s and %s\n"),
43f9d9f3
AD
978 oid_to_hex(current_bad_oid),
979 term_good,
980 term_bad);
ef24c7ca
CC
981 exit(1);
982 }
983
8f69f72f 984 if (!all) {
14dc4899
VA
985 fprintf(stderr, _("No testable commit found.\n"
986 "Maybe you started with bad path parameters?\n"));
8f69f72f
CC
987 exit(4);
988 }
989
4be0deec 990 bisect_rev = &revs.commits->item->object.oid;
ef24c7ca 991
4a7e27e9 992 if (oideq(bisect_rev, current_bad_oid)) {
3c5ff995 993 exit_if_skipped_commits(tried, current_bad_oid);
4be0deec 994 printf("%s is the first %s commit\n", oid_to_hex(bisect_rev),
43f9d9f3 995 term_bad);
69d2cfe6 996 show_diff_tree(r, prefix, revs.commits->item);
ef24c7ca
CC
997 /* This means the bisection process succeeded. */
998 exit(10);
999 }
1000
1001 nr = all - reaches - 1;
6329bade 1002 steps = estimate_bisect_steps(all);
2cfa8357
MM
1003
1004 steps_msg = xstrfmt(Q_("(roughly %d step)", "(roughly %d steps)",
1005 steps), steps);
66f5f6dc
ÆAB
1006 /*
1007 * TRANSLATORS: the last %s will be replaced with "(roughly %d
1008 * steps)" translation.
1009 */
14dc4899
VA
1010 printf(Q_("Bisecting: %d revision left to test after this %s\n",
1011 "Bisecting: %d revisions left to test after this %s\n",
1012 nr), nr, steps_msg);
2cfa8357 1013 free(steps_msg);
ef24c7ca 1014
f3a97718 1015 return bisect_checkout(bisect_rev, no_checkout);
ef24c7ca
CC
1016}
1017
c43cb386
NTND
1018static inline int log2i(int n)
1019{
1020 int log2 = 0;
1021
1022 for (; n > 1; n >>= 1)
1023 log2++;
1024
1025 return log2;
1026}
1027
1028static inline int exp2i(int n)
1029{
1030 return 1 << n;
1031}
1032
1033/*
1034 * Estimate the number of bisect steps left (after the current step)
1035 *
1036 * For any x between 0 included and 2^n excluded, the probability for
1037 * n - 1 steps left looks like:
1038 *
1039 * P(2^n + x) == (2^n - x) / (2^n + x)
1040 *
1041 * and P(2^n + x) < 0.5 means 2^n < 3x
1042 */
1043int estimate_bisect_steps(int all)
1044{
1045 int n, x, e;
1046
1047 if (all < 3)
1048 return 0;
1049
1050 n = log2i(all);
1051 e = exp2i(n);
1052 x = all - e;
1053
1054 return (e < 3 * x) ? n : n - 1;
1055}
fb71a329
PB
1056
1057static int mark_for_removal(const char *refname, const struct object_id *oid,
1058 int flag, void *cb_data)
1059{
1060 struct string_list *refs = cb_data;
1061 char *ref = xstrfmt("refs/bisect%s", refname);
1062 string_list_append(refs, ref);
1063 return 0;
1064}
1065
1066int bisect_clean_state(void)
1067{
1068 int result = 0;
1069
1070 /* There may be some refs packed during bisection */
1071 struct string_list refs_for_removal = STRING_LIST_INIT_NODUP;
1072 for_each_ref_in("refs/bisect", mark_for_removal, (void *) &refs_for_removal);
1073 string_list_append(&refs_for_removal, xstrdup("BISECT_HEAD"));
a9722297 1074 result = delete_refs("bisect: remove", &refs_for_removal, REF_NO_DEREF);
fb71a329
PB
1075 refs_for_removal.strdup_strings = 1;
1076 string_list_clear(&refs_for_removal, 0);
1077 unlink_or_warn(git_path_bisect_expected_rev());
1078 unlink_or_warn(git_path_bisect_ancestors_ok());
1079 unlink_or_warn(git_path_bisect_log());
1080 unlink_or_warn(git_path_bisect_names());
1081 unlink_or_warn(git_path_bisect_run());
1082 unlink_or_warn(git_path_bisect_terms());
1083 /* Cleanup head-name if it got left by an old version of git-bisect */
1084 unlink_or_warn(git_path_head_name());
1085 /*
1086 * Cleanup BISECT_START last to support the --no-checkout option
1087 * introduced in the commit 4796e823a.
1088 */
1089 unlink_or_warn(git_path_bisect_start());
1090
1091 return result;
1092}