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chromium / external / github.com / git / git / refs/tags/v2.4.3 / . / bisect.c
blob: 8c6d843699ab04bc0fe952268d14965943446a17 [file] [log] [blame]
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]1#include "cache.h"
2#include "commit.h"
3#include "diff.h"
4#include "revision.h"
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]5#include "refs.h"
6#include "list-objects.h"
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]7#include "quote.h"
Christian Couder4eb5b642009-04-04 20:59:36[diff] [blame]8#include "sha1-lookup.h"
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]9#include "run-command.h"
Christian Coudere22278c2009-05-28 21:21:16[diff] [blame]10#include "log-tree.h"
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]11#include "bisect.h"
Jeff King902bb362011-05-19 21:34:33[diff] [blame]12#include "sha1-array.h"
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]13#include "argv-array.h"
Christian Couder6212b1a2009-05-09 15:55:38[diff] [blame]14
Christian Couderfad2d312009-05-09 15:55:40[diff] [blame]15static struct sha1_array good_revs;
Christian Couder6212b1a2009-05-09 15:55:38[diff] [blame]16static struct sha1_array skipped_revs;
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]17
Michael Haggertybf427722013-05-25 09:08:23[diff] [blame]18static unsigned char *current_bad_sha1;
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]19
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]20static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
21static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]22static const char *argv_update_ref[] = {"update-ref", "--no-deref", "BISECT_HEAD", NULL, NULL};
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]23
Nguyễn Thái Ngọc Duy208acbf2014-03-25 13:23:26[diff] [blame]24/* Remember to update object flag allocation in object.h */
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]25#define COUNTED (1u<<16)
26
27/*
28 * This is a truly stupid algorithm, but it's only
29 * used for bisection, and we just don't care enough.
30 *
31 * We care just barely enough to avoid recursing for
32 * non-merge entries.
33 */
34static int count_distance(struct commit_list *entry)
35{
36 int nr = 0;
37
38 while (entry) {
39 struct commit *commit = entry->item;
40 struct commit_list *p;
41
42 if (commit->object.flags & (UNINTERESTING | COUNTED))
43 break;
44 if (!(commit->object.flags & TREESAME))
45 nr++;
46 commit->object.flags |= COUNTED;
47 p = commit->parents;
48 entry = p;
49 if (p) {
50 p = p->next;
51 while (p) {
52 nr += count_distance(p);
53 p = p->next;
54 }
55 }
56 }
57
58 return nr;
59}
60
61static void clear_distance(struct commit_list *list)
62{
63 while (list) {
64 struct commit *commit = list->item;
65 commit->object.flags &= ~COUNTED;
66 list = list->next;
67 }
68}
69
70#define DEBUG_BISECT 0
71
72static inline int weight(struct commit_list *elem)
73{
74 return *((int*)(elem->item->util));
75}
76
77static inline void weight_set(struct commit_list *elem, int weight)
78{
79 *((int*)(elem->item->util)) = weight;
80}
81
82static int count_interesting_parents(struct commit *commit)
83{
84 struct commit_list *p;
85 int count;
86
87 for (count = 0, p = commit->parents; p; p = p->next) {
88 if (p->item->object.flags & UNINTERESTING)
89 continue;
90 count++;
91 }
92 return count;
93}
94
95static inline int halfway(struct commit_list *p, int nr)
96{
97 /*
98 * Don't short-cut something we are not going to return!
99 */
100 if (p->item->object.flags & TREESAME)
101 return 0;
102 if (DEBUG_BISECT)
103 return 0;
104 /*
105 * 2 and 3 are halfway of 5.
106 * 3 is halfway of 6 but 2 and 4 are not.
107 */
108 switch (2 * weight(p) - nr) {
109 case -1: case 0: case 1:
110 return 1;
111 default:
112 return 0;
113 }
114}
115
116#if !DEBUG_BISECT
117#define show_list(a,b,c,d) do { ; } while (0)
118#else
119static void show_list(const char *debug, int counted, int nr,
120 struct commit_list *list)
121{
122 struct commit_list *p;
123
124 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
125
126 for (p = list; p; p = p->next) {
127 struct commit_list *pp;
128 struct commit *commit = p->item;
129 unsigned flags = commit->object.flags;
130 enum object_type type;
131 unsigned long size;
132 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
Christian Couder56ff3792010-07-22 13:18:33[diff] [blame]133 const char *subject_start;
134 int subject_len;
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]135
136 fprintf(stderr, "%c%c%c ",
137 (flags & TREESAME) ? ' ' : 'T',
138 (flags & UNINTERESTING) ? 'U' : ' ',
139 (flags & COUNTED) ? 'C' : ' ');
140 if (commit->util)
141 fprintf(stderr, "%3d", weight(p));
142 else
143 fprintf(stderr, "---");
144 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
145 for (pp = commit->parents; pp; pp = pp->next)
146 fprintf(stderr, " %.*s", 8,
147 sha1_to_hex(pp->item->object.sha1));
148
Christian Couder56ff3792010-07-22 13:18:33[diff] [blame]149 subject_len = find_commit_subject(buf, &subject_start);
150 if (subject_len)
151 fprintf(stderr, " %.*s", subject_len, subject_start);
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]152 fprintf(stderr, "\n");
153 }
154}
155#endif /* DEBUG_BISECT */
156
157static struct commit_list *best_bisection(struct commit_list *list, int nr)
158{
159 struct commit_list *p, *best;
160 int best_distance = -1;
161
162 best = list;
163 for (p = list; p; p = p->next) {
164 int distance;
165 unsigned flags = p->item->object.flags;
166
167 if (flags & TREESAME)
168 continue;
169 distance = weight(p);
170 if (nr - distance < distance)
171 distance = nr - distance;
172 if (distance > best_distance) {
173 best = p;
174 best_distance = distance;
175 }
176 }
177
178 return best;
179}
180
181struct commit_dist {
182 struct commit *commit;
183 int distance;
184};
185
186static int compare_commit_dist(const void *a_, const void *b_)
187{
188 struct commit_dist *a, *b;
189
190 a = (struct commit_dist *)a_;
191 b = (struct commit_dist *)b_;
192 if (a->distance != b->distance)
193 return b->distance - a->distance; /* desc sort */
194 return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
195}
196
197static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
198{
199 struct commit_list *p;
200 struct commit_dist *array = xcalloc(nr, sizeof(*array));
201 int cnt, i;
202
203 for (p = list, cnt = 0; p; p = p->next) {
204 int distance;
205 unsigned flags = p->item->object.flags;
206
207 if (flags & TREESAME)
208 continue;
209 distance = weight(p);
210 if (nr - distance < distance)
211 distance = nr - distance;
212 array[cnt].commit = p->item;
213 array[cnt].distance = distance;
214 cnt++;
215 }
216 qsort(array, cnt, sizeof(*array), compare_commit_dist);
217 for (p = list, i = 0; i < cnt; i++) {
Jeff King662174d2014-08-26 10:23:36[diff] [blame]218 char buf[100]; /* enough for dist=%d */
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]219 struct object *obj = &(array[i].commit->object);
220
Jeff King662174d2014-08-26 10:23:36[diff] [blame]221 snprintf(buf, sizeof(buf), "dist=%d", array[i].distance);
222 add_name_decoration(DECORATION_NONE, buf, obj);
223
Christian Coudera2ad79c2009-03-26 04:55:24[diff] [blame]224 p->item = array[i].commit;
225 p = p->next;
226 }
227 if (p)
228 p->next = NULL;
229 free(array);
230 return list;
231}
232
233/*
234 * zero or positive weight is the number of interesting commits it can
235 * reach, including itself. Especially, weight = 0 means it does not
236 * reach any tree-changing commits (e.g. just above uninteresting one
237 * but traversal is with pathspec).
238 *
239 * weight = -1 means it has one parent and its distance is yet to
240 * be computed.
241 *
242 * weight = -2 means it has more than one parent and its distance is
243 * unknown. After running count_distance() first, they will get zero
244 * or positive distance.
245 */
246static struct commit_list *do_find_bisection(struct commit_list *list,
247 int nr, int *weights,
248 int find_all)
249{
250 int n, counted;
251 struct commit_list *p;
252
253 counted = 0;
254
255 for (n = 0, p = list; p; p = p->next) {
256 struct commit *commit = p->item;
257 unsigned flags = commit->object.flags;
258
259 p->item->util = &weights[n++];
260 switch (count_interesting_parents(commit)) {
261 case 0:
262 if (!(flags & TREESAME)) {
263 weight_set(p, 1);
264 counted++;
265 show_list("bisection 2 count one",
266 counted, nr, list);
267 }
268 /*
269 * otherwise, it is known not to reach any
270 * tree-changing commit and gets weight 0.
271 */
272 break;
273 case 1:
274 weight_set(p, -1);
275 break;
276 default:
277 weight_set(p, -2);
278 break;
279 }
280 }
281
282 show_list("bisection 2 initialize", counted, nr, list);
283
284 /*
285 * If you have only one parent in the resulting set
286 * then you can reach one commit more than that parent
287 * can reach. So we do not have to run the expensive
288 * count_distance() for single strand of pearls.
289 *
290 * However, if you have more than one parents, you cannot
291 * just add their distance and one for yourself, since
292 * they usually reach the same ancestor and you would
293 * end up counting them twice that way.
294 *
295 * So we will first count distance of merges the usual
296 * way, and then fill the blanks using cheaper algorithm.
297 */
298 for (p = list; p; p = p->next) {
299 if (p->item->object.flags & UNINTERESTING)
300 continue;
301 if (weight(p) != -2)
302 continue;
303 weight_set(p, count_distance(p));
304 clear_distance(list);
305
306 /* Does it happen to be at exactly half-way? */
307 if (!find_all && halfway(p, nr))
308 return p;
309 counted++;
310 }
311
312 show_list("bisection 2 count_distance", counted, nr, list);
313
314 while (counted < nr) {
315 for (p = list; p; p = p->next) {
316 struct commit_list *q;
317 unsigned flags = p->item->object.flags;
318
319 if (0 <= weight(p))
320 continue;
321 for (q = p->item->parents; q; q = q->next) {
322 if (q->item->object.flags & UNINTERESTING)
323 continue;
324 if (0 <= weight(q))
325 break;
326 }
327 if (!q)
328 continue;
329
330 /*
331 * weight for p is unknown but q is known.
332 * add one for p itself if p is to be counted,
333 * otherwise inherit it from q directly.
334 */
335 if (!(flags & TREESAME)) {
336 weight_set(p, weight(q)+1);
337 counted++;
338 show_list("bisection 2 count one",
339 counted, nr, list);
340 }
341 else
342 weight_set(p, weight(q));
343
344 /* Does it happen to be at exactly half-way? */
345 if (!find_all && halfway(p, nr))
346 return p;
347 }
348 }
349
350 show_list("bisection 2 counted all", counted, nr, list);
351
352 if (!find_all)
353 return best_bisection(list, nr);
354 else
355 return best_bisection_sorted(list, nr);
356}
357
358struct commit_list *find_bisection(struct commit_list *list,
359 int *reaches, int *all,
360 int find_all)
361{
362 int nr, on_list;
363 struct commit_list *p, *best, *next, *last;
364 int *weights;
365
366 show_list("bisection 2 entry", 0, 0, list);
367
368 /*
369 * Count the number of total and tree-changing items on the
370 * list, while reversing the list.
371 */
372 for (nr = on_list = 0, last = NULL, p = list;
373 p;
374 p = next) {
375 unsigned flags = p->item->object.flags;
376
377 next = p->next;
378 if (flags & UNINTERESTING)
379 continue;
380 p->next = last;
381 last = p;
382 if (!(flags & TREESAME))
383 nr++;
384 on_list++;
385 }
386 list = last;
387 show_list("bisection 2 sorted", 0, nr, list);
388
389 *all = nr;
390 weights = xcalloc(on_list, sizeof(*weights));
391
392 /* Do the real work of finding bisection commit. */
393 best = do_find_bisection(list, nr, weights, find_all);
394 if (best) {
395 if (!find_all)
396 best->next = NULL;
397 *reaches = weight(best);
398 }
399 free(weights);
400 return best;
401}
402
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]403static int register_ref(const char *refname, const unsigned char *sha1,
404 int flags, void *cb_data)
405{
406 if (!strcmp(refname, "bad")) {
Michael Haggertybf427722013-05-25 09:08:23[diff] [blame]407 current_bad_sha1 = xmalloc(20);
408 hashcpy(current_bad_sha1, sha1);
Christian Couder59556542013-11-30 20:55:40[diff] [blame]409 } else if (starts_with(refname, "good-")) {
Jeff King902bb362011-05-19 21:34:33[diff] [blame]410 sha1_array_append(&good_revs, sha1);
Christian Couder59556542013-11-30 20:55:40[diff] [blame]411 } else if (starts_with(refname, "skip-")) {
Jeff King902bb362011-05-19 21:34:33[diff] [blame]412 sha1_array_append(&skipped_revs, sha1);
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]413 }
414
415 return 0;
416}
417
418static int read_bisect_refs(void)
419{
420 return for_each_ref_in("refs/bisect/", register_ref, NULL);
421}
422
Linus Torvalds2af202b2009-06-18 17:28:43[diff] [blame]423static void read_bisect_paths(struct argv_array *array)
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]424{
425 struct strbuf str = STRBUF_INIT;
426 const char *filename = git_path("BISECT_NAMES");
427 FILE *fp = fopen(filename, "r");
428
429 if (!fp)
Thomas Rastd824cbb2009-06-27 15:58:46[diff] [blame]430 die_errno("Could not open file '%s'", filename);
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]431
432 while (strbuf_getline(&str, fp, '\n') != EOF) {
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]433 strbuf_trim(&str);
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]434 if (sq_dequote_to_argv_array(str.buf, array))
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]435 die("Badly quoted content in file '%s': %s",
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]436 filename, str.buf);
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]437 }
438
439 strbuf_release(&str);
440 fclose(fp);
441}
442
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]443static char *join_sha1_array_hex(struct sha1_array *array, char delim)
444{
445 struct strbuf joined_hexs = STRBUF_INIT;
446 int i;
447
Jeff King902bb362011-05-19 21:34:33[diff] [blame]448 for (i = 0; i < array->nr; i++) {
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]449 strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
Jeff King902bb362011-05-19 21:34:33[diff] [blame]450 if (i + 1 < array->nr)
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]451 strbuf_addch(&joined_hexs, delim);
452 }
453
454 return strbuf_detach(&joined_hexs, NULL);
455}
456
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]457/*
458 * In this function, passing a not NULL skipped_first is very special.
459 * It means that we want to know if the first commit in the list is
460 * skipped because we will want to test a commit away from it if it is
461 * indeed skipped.
462 * So if the first commit is skipped, we cannot take the shortcut to
463 * just "return list" when we find the first non skipped commit, we
464 * have to return a fully filtered list.
465 *
466 * We use (*skipped_first == -1) to mean "it has been found that the
467 * first commit is not skipped". In this case *skipped_first is set back
468 * to 0 just before the function returns.
469 */
Christian Couder95188642009-03-26 04:55:49[diff] [blame]470struct commit_list *filter_skipped(struct commit_list *list,
471 struct commit_list **tried,
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]472 int show_all,
473 int *count,
474 int *skipped_first)
Christian Couder95188642009-03-26 04:55:49[diff] [blame]475{
476 struct commit_list *filtered = NULL, **f = &filtered;
477
478 *tried = NULL;
479
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]480 if (skipped_first)
481 *skipped_first = 0;
482 if (count)
483 *count = 0;
484
Jeff King902bb362011-05-19 21:34:33[diff] [blame]485 if (!skipped_revs.nr)
Christian Couder95188642009-03-26 04:55:49[diff] [blame]486 return list;
487
Christian Couder95188642009-03-26 04:55:49[diff] [blame]488 while (list) {
489 struct commit_list *next = list->next;
490 list->next = NULL;
Jeff King902bb362011-05-19 21:34:33[diff] [blame]491 if (0 <= sha1_array_lookup(&skipped_revs,
Christian Couderaaaff9e2009-05-09 15:55:43[diff] [blame]492 list->item->object.sha1)) {
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]493 if (skipped_first && !*skipped_first)
494 *skipped_first = 1;
Christian Couder95188642009-03-26 04:55:49[diff] [blame]495 /* Move current to tried list */
496 *tried = list;
497 tried = &list->next;
498 } else {
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]499 if (!show_all) {
500 if (!skipped_first || !*skipped_first)
501 return list;
502 } else if (skipped_first && !*skipped_first) {
503 /* This means we know it's not skipped */
504 *skipped_first = -1;
505 }
Christian Couder95188642009-03-26 04:55:49[diff] [blame]506 /* Move current to filtered list */
507 *f = list;
508 f = &list->next;
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]509 if (count)
510 (*count)++;
Christian Couder95188642009-03-26 04:55:49[diff] [blame]511 }
512 list = next;
513 }
514
Christian Couder9af35892009-06-06 04:41:33[diff] [blame]515 if (skipped_first && *skipped_first == -1)
516 *skipped_first = 0;
517
Christian Couder95188642009-03-26 04:55:49[diff] [blame]518 return filtered;
519}
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]520
Christian Couderebc95292009-06-13 05:21:06[diff] [blame]521#define PRN_MODULO 32768
522
523/*
524 * This is a pseudo random number generator based on "man 3 rand".
525 * It is not used properly because the seed is the argument and it
526 * is increased by one between each call, but that should not matter
527 * for this application.
528 */
John Keeping7b96d882013-04-03 19:17:55[diff] [blame]529static unsigned get_prn(unsigned count) {
Christian Couderebc95292009-06-13 05:21:06[diff] [blame]530 count = count * 1103515245 + 12345;
John Keeping7b96d882013-04-03 19:17:55[diff] [blame]531 return (count/65536) % PRN_MODULO;
Christian Couderebc95292009-06-13 05:21:06[diff] [blame]532}
533
534/*
535 * Custom integer square root from
536 * http://en.wikipedia.org/wiki/Integer_square_root
537 */
538static int sqrti(int val)
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]539{
Christian Couderebc95292009-06-13 05:21:06[diff] [blame]540 float d, x = val;
541
542 if (val == 0)
543 return 0;
544
545 do {
546 float y = (x + (float)val / x) / 2;
547 d = (y > x) ? y - x : x - y;
548 x = y;
549 } while (d >= 0.5);
550
551 return (int)x;
552}
553
554static struct commit_list *skip_away(struct commit_list *list, int count)
555{
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]556 struct commit_list *cur, *previous;
Christian Couderebc95292009-06-13 05:21:06[diff] [blame]557 int prn, index, i;
558
559 prn = get_prn(count);
560 index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]561
562 cur = list;
563 previous = NULL;
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]564
565 for (i = 0; cur; cur = cur->next, i++) {
566 if (i == index) {
567 if (hashcmp(cur->item->object.sha1, current_bad_sha1))
568 return cur;
569 if (previous)
570 return previous;
571 return list;
572 }
573 previous = cur;
574 }
575
576 return list;
577}
578
579static struct commit_list *managed_skipped(struct commit_list *list,
580 struct commit_list **tried)
581{
582 int count, skipped_first;
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]583
584 *tried = NULL;
585
Jeff King902bb362011-05-19 21:34:33[diff] [blame]586 if (!skipped_revs.nr)
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]587 return list;
588
589 list = filter_skipped(list, tried, 0, &count, &skipped_first);
590
591 if (!skipped_first)
592 return list;
593
Christian Couderebc95292009-06-13 05:21:06[diff] [blame]594 return skip_away(list, count);
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]595}
596
Christian Coudera22347c2009-05-17 15:36:44[diff] [blame]597static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
598 const char *bad_format, const char *good_format,
599 int read_paths)
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]600{
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]601 struct argv_array rev_argv = ARGV_ARRAY_INIT;
Christian Couderfad2d312009-05-09 15:55:40[diff] [blame]602 int i;
603
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]604 init_revisions(revs, prefix);
605 revs->abbrev = 0;
606 revs->commit_format = CMIT_FMT_UNSPECIFIED;
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]607
Christian Couder1c953a12009-05-09 15:55:41[diff] [blame]608 /* rev_argv.argv[0] will be ignored by setup_revisions */
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]609 argv_array_push(&rev_argv, "bisect_rev_setup");
610 argv_array_pushf(&rev_argv, bad_format, sha1_to_hex(current_bad_sha1));
Jeff King902bb362011-05-19 21:34:33[diff] [blame]611 for (i = 0; i < good_revs.nr; i++)
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]612 argv_array_pushf(&rev_argv, good_format,
613 sha1_to_hex(good_revs.sha1[i]));
614 argv_array_push(&rev_argv, "--");
Christian Coudera22347c2009-05-17 15:36:44[diff] [blame]615 if (read_paths)
616 read_bisect_paths(&rev_argv);
Christian Couder1bf072e2009-03-26 04:55:54[diff] [blame]617
Jeff King8a534b62011-09-13 21:58:14[diff] [blame]618 setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
619 /* XXX leak rev_argv, as "revs" may still be pointing to it */
Christian Couder3b437b02009-03-26 04:55:59[diff] [blame]620}
621
Christian Coudera22347c2009-05-17 15:36:44[diff] [blame]622static void bisect_common(struct rev_info *revs)
Christian Couder2ace9722009-04-19 09:55:57[diff] [blame]623{
Christian Couder2ace9722009-04-19 09:55:57[diff] [blame]624 if (prepare_revision_walk(revs))
625 die("revision walk setup failed");
626 if (revs->tree_objects)
Nguyễn Thái Ngọc Duye76a5fb2013-08-16 09:52:06[diff] [blame]627 mark_edges_uninteresting(revs, NULL);
Christian Couder2ace9722009-04-19 09:55:57[diff] [blame]628}
629
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]630static void exit_if_skipped_commits(struct commit_list *tried,
631 const unsigned char *bad)
632{
633 if (!tried)
634 return;
635
636 printf("There are only 'skip'ped commits left to test.\n"
637 "The first bad commit could be any of:\n");
638 print_commit_list(tried, "%s\n", "%s\n");
639 if (bad)
640 printf("%s\n", sha1_to_hex(bad));
641 printf("We cannot bisect more!\n");
642 exit(2);
643}
644
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]645static int is_expected_rev(const unsigned char *sha1)
646{
647 const char *filename = git_path("BISECT_EXPECTED_REV");
648 struct stat st;
649 struct strbuf str = STRBUF_INIT;
650 FILE *fp;
651 int res = 0;
652
653 if (stat(filename, &st) || !S_ISREG(st.st_mode))
654 return 0;
655
656 fp = fopen(filename, "r");
657 if (!fp)
658 return 0;
659
660 if (strbuf_getline(&str, fp, '\n') != EOF)
661 res = !strcmp(str.buf, sha1_to_hex(sha1));
662
663 strbuf_release(&str);
664 fclose(fp);
665
666 return res;
667}
668
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]669static void mark_expected_rev(char *bisect_rev_hex)
670{
671 int len = strlen(bisect_rev_hex);
672 const char *filename = git_path("BISECT_EXPECTED_REV");
673 int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
674
675 if (fd < 0)
Thomas Rastd824cbb2009-06-27 15:58:46[diff] [blame]676 die_errno("could not create file '%s'", filename);
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]677
678 bisect_rev_hex[len] = '\n';
679 write_or_die(fd, bisect_rev_hex, len + 1);
680 bisect_rev_hex[len] = '\0';
681
682 if (close(fd) < 0)
683 die("closing file %s: %s", filename, strerror(errno));
684}
685
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]686static int bisect_checkout(char *bisect_rev_hex, int no_checkout)
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]687{
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]688
689 mark_expected_rev(bisect_rev_hex);
690
691 argv_checkout[2] = bisect_rev_hex;
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]692 if (no_checkout) {
693 argv_update_ref[3] = bisect_rev_hex;
694 if (run_command_v_opt(argv_update_ref, RUN_GIT_CMD))
695 die("update-ref --no-deref HEAD failed on %s",
696 bisect_rev_hex);
697 } else {
Elia Pinto4824d1b2014-01-29 13:25:00[diff] [blame]698 int res;
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]699 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
700 if (res)
701 exit(res);
702 }
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]703
704 argv_show_branch[1] = bisect_rev_hex;
705 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
706}
707
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]708static struct commit *get_commit_reference(const unsigned char *sha1)
709{
710 struct commit *r = lookup_commit_reference(sha1);
711 if (!r)
712 die("Not a valid commit name %s", sha1_to_hex(sha1));
713 return r;
714}
715
716static struct commit **get_bad_and_good_commits(int *rev_nr)
717{
Jeff King902bb362011-05-19 21:34:33[diff] [blame]718 int len = 1 + good_revs.nr;
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]719 struct commit **rev = xmalloc(len * sizeof(*rev));
720 int i, n = 0;
721
722 rev[n++] = get_commit_reference(current_bad_sha1);
Jeff King902bb362011-05-19 21:34:33[diff] [blame]723 for (i = 0; i < good_revs.nr; i++)
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]724 rev[n++] = get_commit_reference(good_revs.sha1[i]);
725 *rev_nr = n;
726
727 return rev;
728}
729
730static void handle_bad_merge_base(void)
731{
732 if (is_expected_rev(current_bad_sha1)) {
733 char *bad_hex = sha1_to_hex(current_bad_sha1);
734 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
735
736 fprintf(stderr, "The merge base %s is bad.\n"
737 "This means the bug has been fixed "
738 "between %s and [%s].\n",
739 bad_hex, bad_hex, good_hex);
740
741 exit(3);
742 }
743
744 fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
745 "git bisect cannot work properly in this case.\n"
746 "Maybe you mistake good and bad revs?\n");
747 exit(1);
748}
749
Linus Torvalds2af202b2009-06-18 17:28:43[diff] [blame]750static void handle_skipped_merge_base(const unsigned char *mb)
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]751{
752 char *mb_hex = sha1_to_hex(mb);
753 char *bad_hex = sha1_to_hex(current_bad_sha1);
754 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
755
Thiago Farinabd757c12010-01-03 16:20:30[diff] [blame]756 warning("the merge base between %s and [%s] "
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]757 "must be skipped.\n"
758 "So we cannot be sure the first bad commit is "
759 "between %s and %s.\n"
Thiago Farinabd757c12010-01-03 16:20:30[diff] [blame]760 "We continue anyway.",
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]761 bad_hex, good_hex, mb_hex, bad_hex);
762 free(good_hex);
763}
764
765/*
766 * "check_merge_bases" checks that merge bases are not "bad".
767 *
768 * - If one is "bad", it means the user assumed something wrong
769 * and we must exit with a non 0 error code.
770 * - If one is "good", that's good, we have nothing to do.
771 * - If one is "skipped", we can't know but we should warn.
772 * - If we don't know, we should check it out and ask the user to test.
773 */
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]774static void check_merge_bases(int no_checkout)
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]775{
776 struct commit_list *result;
777 int rev_nr;
778 struct commit **rev = get_bad_and_good_commits(&rev_nr);
779
Junio C Hamano2ce406c2014-10-30 19:20:44[diff] [blame]780 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]781
782 for (; result; result = result->next) {
783 const unsigned char *mb = result->item->object.sha1;
784 if (!hashcmp(mb, current_bad_sha1)) {
785 handle_bad_merge_base();
Jeff King902bb362011-05-19 21:34:33[diff] [blame]786 } else if (0 <= sha1_array_lookup(&good_revs, mb)) {
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]787 continue;
Jeff King902bb362011-05-19 21:34:33[diff] [blame]788 } else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]789 handle_skipped_merge_base(mb);
790 } else {
791 printf("Bisecting: a merge base must be tested\n");
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]792 exit(bisect_checkout(sha1_to_hex(mb), no_checkout));
Christian Couderc0537662009-05-09 15:55:45[diff] [blame]793 }
794 }
795
796 free(rev);
797 free_commit_list(result);
798}
799
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]800static int check_ancestors(const char *prefix)
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]801{
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]802 struct rev_info revs;
803 struct object_array pending_copy;
René Scharfe86a0a402011-10-01 16:16:08[diff] [blame]804 int res;
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]805
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]806 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]807
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]808 /* Save pending objects, so they can be cleaned up later. */
René Scharfe353f5652011-10-01 16:01:12[diff] [blame]809 pending_copy = revs.pending;
810 revs.leak_pending = 1;
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]811
René Scharfe353f5652011-10-01 16:01:12[diff] [blame]812 /*
813 * bisect_common calls prepare_revision_walk right away, which
814 * (together with .leak_pending = 1) makes us the sole owner of
815 * the list of pending objects.
816 */
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]817 bisect_common(&revs);
818 res = (revs.commits != NULL);
819
820 /* Clean up objects used, as they will be reused. */
René Scharfe86a0a402011-10-01 16:16:08[diff] [blame]821 clear_commit_marks_for_object_array(&pending_copy, ALL_REV_FLAGS);
René Scharfe353f5652011-10-01 16:01:12[diff] [blame]822 free(pending_copy.objects);
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]823
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]824 return res;
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]825}
826
827/*
828 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
829 * ancestor of the "bad" rev.
830 *
831 * If that's not the case, we need to check the merge bases.
832 * If a merge base must be tested by the user, its source code will be
833 * checked out to be tested by the user and we will exit.
834 */
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]835static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]836{
Ramsay Jonesd292bfa2012-09-04 17:30:21[diff] [blame]837 char *filename = git_pathdup("BISECT_ANCESTORS_OK");
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]838 struct stat st;
839 int fd;
840
841 if (!current_bad_sha1)
842 die("a bad revision is needed");
843
844 /* Check if file BISECT_ANCESTORS_OK exists. */
845 if (!stat(filename, &st) && S_ISREG(st.st_mode))
Michael Haggerty144e7092012-04-26 22:26:59[diff] [blame]846 goto done;
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]847
848 /* Bisecting with no good rev is ok. */
Jeff King902bb362011-05-19 21:34:33[diff] [blame]849 if (good_revs.nr == 0)
Michael Haggerty144e7092012-04-26 22:26:59[diff] [blame]850 goto done;
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]851
Christian Couder2d938fc2009-05-17 15:36:46[diff] [blame]852 /* Check if all good revs are ancestor of the bad rev. */
853 if (check_ancestors(prefix))
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]854 check_merge_bases(no_checkout);
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]855
856 /* Create file BISECT_ANCESTORS_OK. */
857 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
858 if (fd < 0)
859 warning("could not create file '%s': %s",
860 filename, strerror(errno));
861 else
862 close(fd);
Michael Haggerty144e7092012-04-26 22:26:59[diff] [blame]863 done:
864 free(filename);
Christian Couderd937d4a2009-05-09 15:55:46[diff] [blame]865}
866
867/*
Christian Coudere22278c2009-05-28 21:21:16[diff] [blame]868 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
869 */
870static void show_diff_tree(const char *prefix, struct commit *commit)
871{
872 struct rev_info opt;
873
874 /* diff-tree init */
875 init_revisions(&opt, prefix);
876 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
877 opt.abbrev = 0;
878 opt.diff = 1;
879
880 /* This is what "--pretty" does */
881 opt.verbose_header = 1;
882 opt.use_terminator = 0;
883 opt.commit_format = CMIT_FMT_DEFAULT;
884
885 /* diff-tree init */
886 if (!opt.diffopt.output_format)
887 opt.diffopt.output_format = DIFF_FORMAT_RAW;
888
889 log_tree_commit(&opt, commit);
890}
891
892/*
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]893 * We use the convention that exiting with an exit code 10 means that
894 * the bisection process finished successfully.
895 * In this case the calling shell script should exit 0.
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]896 *
897 * If no_checkout is non-zero, the bisection process does not
898 * checkout the trial commit but instead simply updates BISECT_HEAD.
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]899 */
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]900int bisect_next_all(const char *prefix, int no_checkout)
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]901{
902 struct rev_info revs;
903 struct commit_list *tried;
David Ripton6329bad2010-01-19 15:13:33[diff] [blame]904 int reaches = 0, all = 0, nr, steps;
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]905 const unsigned char *bisect_rev;
906 char bisect_rev_hex[41];
907
Christian Couder2b020692009-05-09 15:55:42[diff] [blame]908 if (read_bisect_refs())
909 die("reading bisect refs failed");
910
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]911 check_good_are_ancestors_of_bad(prefix, no_checkout);
Christian Couder08719842009-05-09 15:55:47[diff] [blame]912
Christian Coudera22347c2009-05-17 15:36:44[diff] [blame]913 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
914 revs.limited = 1;
Christian Couder2b020692009-05-09 15:55:42[diff] [blame]915
Christian Coudera22347c2009-05-17 15:36:44[diff] [blame]916 bisect_common(&revs);
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]917
Christian Coudera22347c2009-05-17 15:36:44[diff] [blame]918 revs.commits = find_bisection(revs.commits, &reaches, &all,
Jeff King902bb362011-05-19 21:34:33[diff] [blame]919 !!skipped_revs.nr);
Christian Couder62d0b0d2009-06-06 04:41:34[diff] [blame]920 revs.commits = managed_skipped(revs.commits, &tried);
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]921
922 if (!revs.commits) {
923 /*
924 * We should exit here only if the "bad"
925 * commit is also a "skip" commit.
926 */
927 exit_if_skipped_commits(tried, NULL);
928
929 printf("%s was both good and bad\n",
930 sha1_to_hex(current_bad_sha1));
931 exit(1);
932 }
933
Christian Couder8f69f722010-02-28 22:19:09[diff] [blame]934 if (!all) {
935 fprintf(stderr, "No testable commit found.\n"
936 "Maybe you started with bad path parameters?\n");
937 exit(4);
938 }
939
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]940 bisect_rev = revs.commits->item->object.sha1;
941 memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
942
943 if (!hashcmp(bisect_rev, current_bad_sha1)) {
944 exit_if_skipped_commits(tried, current_bad_sha1);
Nanako Shiraishi21d0bc22009-08-26 08:38:50[diff] [blame]945 printf("%s is the first bad commit\n", bisect_rev_hex);
Christian Coudere22278c2009-05-28 21:21:16[diff] [blame]946 show_diff_tree(prefix, revs.commits->item);
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]947 /* This means the bisection process succeeded. */
948 exit(10);
949 }
950
951 nr = all - reaches - 1;
David Ripton6329bad2010-01-19 15:13:33[diff] [blame]952 steps = estimate_bisect_steps(all);
953 printf("Bisecting: %d revision%s left to test after this "
954 "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
955 steps, (steps == 1 ? "" : "s"));
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]956
Jon Seymourfee92fc2011-08-04 12:01:00[diff] [blame]957 return bisect_checkout(bisect_rev_hex, no_checkout);
Christian Couderef24c7c2009-04-19 09:56:07[diff] [blame]958}
959
Nguyễn Thái Ngọc Duyc43cb382012-10-26 15:53:50[diff] [blame]960static inline int log2i(int n)
961{
962 int log2 = 0;
963
964 for (; n > 1; n >>= 1)
965 log2++;
966
967 return log2;
968}
969
970static inline int exp2i(int n)
971{
972 return 1 << n;
973}
974
975/*
976 * Estimate the number of bisect steps left (after the current step)
977 *
978 * For any x between 0 included and 2^n excluded, the probability for
979 * n - 1 steps left looks like:
980 *
981 * P(2^n + x) == (2^n - x) / (2^n + x)
982 *
983 * and P(2^n + x) < 0.5 means 2^n < 3x
984 */
985int estimate_bisect_steps(int all)
986{
987 int n, x, e;
988
989 if (all < 3)
990 return 0;
991
992 n = log2i(all);
993 e = exp2i(n);
994 x = all - e;
995
996 return (e < 3 * x) ? n : n - 1;
997}