bisect: display first bad commit without forking a new process
[git/git.git] / bisect.c
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1#include "cache.h"
2#include "commit.h"
3#include "diff.h"
4#include "revision.h"
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5#include "refs.h"
6#include "list-objects.h"
3b437b0d 7#include "quote.h"
4eb5b646 8#include "sha1-lookup.h"
ef24c7ca 9#include "run-command.h"
e22278c0 10#include "log-tree.h"
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11#include "bisect.h"
12
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13struct sha1_array {
14 unsigned char (*sha1)[20];
15 int sha1_nr;
16 int sha1_alloc;
1da8c4fc 17 int sorted;
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18};
19
fad2d31d 20static struct sha1_array good_revs;
6212b1aa 21static struct sha1_array skipped_revs;
1bf072e3 22
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23static const unsigned char *current_bad_sha1;
24
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25struct argv_array {
26 const char **argv;
27 int argv_nr;
28 int argv_alloc;
29};
30
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31static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
32static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
33
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34/* bits #0-15 in revision.h */
35
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
81#define DEBUG_BISECT 0
82
83static inline int weight(struct commit_list *elem)
84{
85 return *((int*)(elem->item->util));
86}
87
88static inline void weight_set(struct commit_list *elem, int weight)
89{
90 *((int*)(elem->item->util)) = weight;
91}
92
93static int count_interesting_parents(struct commit *commit)
94{
95 struct commit_list *p;
96 int count;
97
98 for (count = 0, p = commit->parents; p; p = p->next) {
99 if (p->item->object.flags & UNINTERESTING)
100 continue;
101 count++;
102 }
103 return count;
104}
105
106static inline int halfway(struct commit_list *p, int nr)
107{
108 /*
109 * Don't short-cut something we are not going to return!
110 */
111 if (p->item->object.flags & TREESAME)
112 return 0;
113 if (DEBUG_BISECT)
114 return 0;
115 /*
116 * 2 and 3 are halfway of 5.
117 * 3 is halfway of 6 but 2 and 4 are not.
118 */
119 switch (2 * weight(p) - nr) {
120 case -1: case 0: case 1:
121 return 1;
122 default:
123 return 0;
124 }
125}
126
127#if !DEBUG_BISECT
128#define show_list(a,b,c,d) do { ; } while (0)
129#else
130static void show_list(const char *debug, int counted, int nr,
131 struct commit_list *list)
132{
133 struct commit_list *p;
134
135 fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
136
137 for (p = list; p; p = p->next) {
138 struct commit_list *pp;
139 struct commit *commit = p->item;
140 unsigned flags = commit->object.flags;
141 enum object_type type;
142 unsigned long size;
143 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
144 char *ep, *sp;
145
146 fprintf(stderr, "%c%c%c ",
147 (flags & TREESAME) ? ' ' : 'T',
148 (flags & UNINTERESTING) ? 'U' : ' ',
149 (flags & COUNTED) ? 'C' : ' ');
150 if (commit->util)
151 fprintf(stderr, "%3d", weight(p));
152 else
153 fprintf(stderr, "---");
154 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
155 for (pp = commit->parents; pp; pp = pp->next)
156 fprintf(stderr, " %.*s", 8,
157 sha1_to_hex(pp->item->object.sha1));
158
159 sp = strstr(buf, "\n\n");
160 if (sp) {
161 sp += 2;
162 for (ep = sp; *ep && *ep != '\n'; ep++)
163 ;
164 fprintf(stderr, " %.*s", (int)(ep - sp), sp);
165 }
166 fprintf(stderr, "\n");
167 }
168}
169#endif /* DEBUG_BISECT */
170
171static struct commit_list *best_bisection(struct commit_list *list, int nr)
172{
173 struct commit_list *p, *best;
174 int best_distance = -1;
175
176 best = list;
177 for (p = list; p; p = p->next) {
178 int distance;
179 unsigned flags = p->item->object.flags;
180
181 if (flags & TREESAME)
182 continue;
183 distance = weight(p);
184 if (nr - distance < distance)
185 distance = nr - distance;
186 if (distance > best_distance) {
187 best = p;
188 best_distance = distance;
189 }
190 }
191
192 return best;
193}
194
195struct commit_dist {
196 struct commit *commit;
197 int distance;
198};
199
200static int compare_commit_dist(const void *a_, const void *b_)
201{
202 struct commit_dist *a, *b;
203
204 a = (struct commit_dist *)a_;
205 b = (struct commit_dist *)b_;
206 if (a->distance != b->distance)
207 return b->distance - a->distance; /* desc sort */
208 return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
209}
210
211static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
212{
213 struct commit_list *p;
214 struct commit_dist *array = xcalloc(nr, sizeof(*array));
215 int cnt, i;
216
217 for (p = list, cnt = 0; p; p = p->next) {
218 int distance;
219 unsigned flags = p->item->object.flags;
220
221 if (flags & TREESAME)
222 continue;
223 distance = weight(p);
224 if (nr - distance < distance)
225 distance = nr - distance;
226 array[cnt].commit = p->item;
227 array[cnt].distance = distance;
228 cnt++;
229 }
230 qsort(array, cnt, sizeof(*array), compare_commit_dist);
231 for (p = list, i = 0; i < cnt; i++) {
232 struct name_decoration *r = xmalloc(sizeof(*r) + 100);
233 struct object *obj = &(array[i].commit->object);
234
235 sprintf(r->name, "dist=%d", array[i].distance);
236 r->next = add_decoration(&name_decoration, obj, r);
237 p->item = array[i].commit;
238 p = p->next;
239 }
240 if (p)
241 p->next = NULL;
242 free(array);
243 return list;
244}
245
246/*
247 * zero or positive weight is the number of interesting commits it can
248 * reach, including itself. Especially, weight = 0 means it does not
249 * reach any tree-changing commits (e.g. just above uninteresting one
250 * but traversal is with pathspec).
251 *
252 * weight = -1 means it has one parent and its distance is yet to
253 * be computed.
254 *
255 * weight = -2 means it has more than one parent and its distance is
256 * unknown. After running count_distance() first, they will get zero
257 * or positive distance.
258 */
259static struct commit_list *do_find_bisection(struct commit_list *list,
260 int nr, int *weights,
261 int find_all)
262{
263 int n, counted;
264 struct commit_list *p;
265
266 counted = 0;
267
268 for (n = 0, p = list; p; p = p->next) {
269 struct commit *commit = p->item;
270 unsigned flags = commit->object.flags;
271
272 p->item->util = &weights[n++];
273 switch (count_interesting_parents(commit)) {
274 case 0:
275 if (!(flags & TREESAME)) {
276 weight_set(p, 1);
277 counted++;
278 show_list("bisection 2 count one",
279 counted, nr, list);
280 }
281 /*
282 * otherwise, it is known not to reach any
283 * tree-changing commit and gets weight 0.
284 */
285 break;
286 case 1:
287 weight_set(p, -1);
288 break;
289 default:
290 weight_set(p, -2);
291 break;
292 }
293 }
294
295 show_list("bisection 2 initialize", counted, nr, list);
296
297 /*
298 * If you have only one parent in the resulting set
299 * then you can reach one commit more than that parent
300 * can reach. So we do not have to run the expensive
301 * count_distance() for single strand of pearls.
302 *
303 * However, if you have more than one parents, you cannot
304 * just add their distance and one for yourself, since
305 * they usually reach the same ancestor and you would
306 * end up counting them twice that way.
307 *
308 * So we will first count distance of merges the usual
309 * way, and then fill the blanks using cheaper algorithm.
310 */
311 for (p = list; p; p = p->next) {
312 if (p->item->object.flags & UNINTERESTING)
313 continue;
314 if (weight(p) != -2)
315 continue;
316 weight_set(p, count_distance(p));
317 clear_distance(list);
318
319 /* Does it happen to be at exactly half-way? */
320 if (!find_all && halfway(p, nr))
321 return p;
322 counted++;
323 }
324
325 show_list("bisection 2 count_distance", counted, nr, list);
326
327 while (counted < nr) {
328 for (p = list; p; p = p->next) {
329 struct commit_list *q;
330 unsigned flags = p->item->object.flags;
331
332 if (0 <= weight(p))
333 continue;
334 for (q = p->item->parents; q; q = q->next) {
335 if (q->item->object.flags & UNINTERESTING)
336 continue;
337 if (0 <= weight(q))
338 break;
339 }
340 if (!q)
341 continue;
342
343 /*
344 * weight for p is unknown but q is known.
345 * add one for p itself if p is to be counted,
346 * otherwise inherit it from q directly.
347 */
348 if (!(flags & TREESAME)) {
349 weight_set(p, weight(q)+1);
350 counted++;
351 show_list("bisection 2 count one",
352 counted, nr, list);
353 }
354 else
355 weight_set(p, weight(q));
356
357 /* Does it happen to be at exactly half-way? */
358 if (!find_all && halfway(p, nr))
359 return p;
360 }
361 }
362
363 show_list("bisection 2 counted all", counted, nr, list);
364
365 if (!find_all)
366 return best_bisection(list, nr);
367 else
368 return best_bisection_sorted(list, nr);
369}
370
371struct commit_list *find_bisection(struct commit_list *list,
372 int *reaches, int *all,
373 int find_all)
374{
375 int nr, on_list;
376 struct commit_list *p, *best, *next, *last;
377 int *weights;
378
379 show_list("bisection 2 entry", 0, 0, list);
380
381 /*
382 * Count the number of total and tree-changing items on the
383 * list, while reversing the list.
384 */
385 for (nr = on_list = 0, last = NULL, p = list;
386 p;
387 p = next) {
388 unsigned flags = p->item->object.flags;
389
390 next = p->next;
391 if (flags & UNINTERESTING)
392 continue;
393 p->next = last;
394 last = p;
395 if (!(flags & TREESAME))
396 nr++;
397 on_list++;
398 }
399 list = last;
400 show_list("bisection 2 sorted", 0, nr, list);
401
402 *all = nr;
403 weights = xcalloc(on_list, sizeof(*weights));
404
405 /* Do the real work of finding bisection commit. */
406 best = do_find_bisection(list, nr, weights, find_all);
407 if (best) {
408 if (!find_all)
409 best->next = NULL;
410 *reaches = weight(best);
411 }
412 free(weights);
413 return best;
414}
415
1c953a1f 416static void argv_array_push(struct argv_array *array, const char *string)
3755ccdb 417{
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418 ALLOC_GROW(array->argv, array->argv_nr + 1, array->argv_alloc);
419 array->argv[array->argv_nr++] = string;
420}
3755ccdb 421
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422static void argv_array_push_sha1(struct argv_array *array,
423 const unsigned char *sha1,
424 const char *format)
425{
426 struct strbuf buf = STRBUF_INIT;
3755ccdb 427 strbuf_addf(&buf, format, sha1_to_hex(sha1));
1c953a1f 428 argv_array_push(array, strbuf_detach(&buf, NULL));
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429}
430
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431static void sha1_array_push(struct sha1_array *array,
432 const unsigned char *sha1)
433{
434 ALLOC_GROW(array->sha1, array->sha1_nr + 1, array->sha1_alloc);
435 hashcpy(array->sha1[array->sha1_nr++], sha1);
436}
437
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438static int register_ref(const char *refname, const unsigned char *sha1,
439 int flags, void *cb_data)
440{
441 if (!strcmp(refname, "bad")) {
ef24c7ca 442 current_bad_sha1 = sha1;
1bf072e3 443 } else if (!prefixcmp(refname, "good-")) {
fad2d31d 444 sha1_array_push(&good_revs, sha1);
1bf072e3 445 } else if (!prefixcmp(refname, "skip-")) {
fad2d31d 446 sha1_array_push(&skipped_revs, sha1);
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447 }
448
449 return 0;
450}
451
452static int read_bisect_refs(void)
453{
454 return for_each_ref_in("refs/bisect/", register_ref, NULL);
455}
456
1c953a1f 457void read_bisect_paths(struct argv_array *array)
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458{
459 struct strbuf str = STRBUF_INIT;
460 const char *filename = git_path("BISECT_NAMES");
461 FILE *fp = fopen(filename, "r");
462
463 if (!fp)
464 die("Could not open file '%s': %s", filename, strerror(errno));
465
466 while (strbuf_getline(&str, fp, '\n') != EOF) {
467 char *quoted;
468 int res;
469
470 strbuf_trim(&str);
471 quoted = strbuf_detach(&str, NULL);
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472 res = sq_dequote_to_argv(quoted, &array->argv,
473 &array->argv_nr, &array->argv_alloc);
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474 if (res)
475 die("Badly quoted content in file '%s': %s",
476 filename, quoted);
477 }
478
479 strbuf_release(&str);
480 fclose(fp);
481}
482
aaaff9e2 483static int array_cmp(const void *a, const void *b)
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484{
485 return hashcmp(a, b);
486}
487
aaaff9e2 488static void sort_sha1_array(struct sha1_array *array)
95188648 489{
aaaff9e2 490 qsort(array->sha1, array->sha1_nr, sizeof(*array->sha1), array_cmp);
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491
492 array->sorted = 1;
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493}
494
aaaff9e2 495static const unsigned char *sha1_access(size_t index, void *table)
4eb5b646 496{
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497 unsigned char (*array)[20] = table;
498 return array[index];
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499}
500
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501static int lookup_sha1_array(struct sha1_array *array,
502 const unsigned char *sha1)
95188648 503{
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504 if (!array->sorted)
505 sort_sha1_array(array);
506
aaaff9e2 507 return sha1_pos(sha1, array->sha1, array->sha1_nr, sha1_access);
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508}
509
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510static char *join_sha1_array_hex(struct sha1_array *array, char delim)
511{
512 struct strbuf joined_hexs = STRBUF_INIT;
513 int i;
514
515 for (i = 0; i < array->sha1_nr; i++) {
516 strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
517 if (i + 1 < array->sha1_nr)
518 strbuf_addch(&joined_hexs, delim);
519 }
520
521 return strbuf_detach(&joined_hexs, NULL);
522}
523
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524struct commit_list *filter_skipped(struct commit_list *list,
525 struct commit_list **tried,
526 int show_all)
527{
528 struct commit_list *filtered = NULL, **f = &filtered;
529
530 *tried = NULL;
531
6212b1aa 532 if (!skipped_revs.sha1_nr)
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533 return list;
534
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535 while (list) {
536 struct commit_list *next = list->next;
537 list->next = NULL;
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538 if (0 <= lookup_sha1_array(&skipped_revs,
539 list->item->object.sha1)) {
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540 /* Move current to tried list */
541 *tried = list;
542 tried = &list->next;
543 } else {
544 if (!show_all)
545 return list;
546 /* Move current to filtered list */
547 *f = list;
548 f = &list->next;
549 }
550 list = next;
551 }
552
553 return filtered;
554}
1bf072e3 555
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556static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
557 const char *bad_format, const char *good_format,
558 int read_paths)
1bf072e3 559{
2b020695 560 struct argv_array rev_argv = { NULL, 0, 0 };
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561 int i;
562
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563 init_revisions(revs, prefix);
564 revs->abbrev = 0;
565 revs->commit_format = CMIT_FMT_UNSPECIFIED;
1bf072e3 566
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567 /* rev_argv.argv[0] will be ignored by setup_revisions */
568 argv_array_push(&rev_argv, xstrdup("bisect_rev_setup"));
a22347c6 569 argv_array_push_sha1(&rev_argv, current_bad_sha1, bad_format);
fad2d31d 570 for (i = 0; i < good_revs.sha1_nr; i++)
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571 argv_array_push_sha1(&rev_argv, good_revs.sha1[i],
572 good_format);
1c953a1f 573 argv_array_push(&rev_argv, xstrdup("--"));
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574 if (read_paths)
575 read_bisect_paths(&rev_argv);
1c953a1f 576 argv_array_push(&rev_argv, NULL);
3b437b0d 577
1c953a1f 578 setup_revisions(rev_argv.argv_nr, rev_argv.argv, revs, NULL);
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579}
580
a22347c6 581static void bisect_common(struct rev_info *revs)
2ace9727 582{
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583 if (prepare_revision_walk(revs))
584 die("revision walk setup failed");
585 if (revs->tree_objects)
586 mark_edges_uninteresting(revs->commits, revs, NULL);
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587}
588
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589static void exit_if_skipped_commits(struct commit_list *tried,
590 const unsigned char *bad)
591{
592 if (!tried)
593 return;
594
595 printf("There are only 'skip'ped commits left to test.\n"
596 "The first bad commit could be any of:\n");
597 print_commit_list(tried, "%s\n", "%s\n");
598 if (bad)
599 printf("%s\n", sha1_to_hex(bad));
600 printf("We cannot bisect more!\n");
601 exit(2);
602}
603
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604static int is_expected_rev(const unsigned char *sha1)
605{
606 const char *filename = git_path("BISECT_EXPECTED_REV");
607 struct stat st;
608 struct strbuf str = STRBUF_INIT;
609 FILE *fp;
610 int res = 0;
611
612 if (stat(filename, &st) || !S_ISREG(st.st_mode))
613 return 0;
614
615 fp = fopen(filename, "r");
616 if (!fp)
617 return 0;
618
619 if (strbuf_getline(&str, fp, '\n') != EOF)
620 res = !strcmp(str.buf, sha1_to_hex(sha1));
621
622 strbuf_release(&str);
623 fclose(fp);
624
625 return res;
626}
627
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628static void mark_expected_rev(char *bisect_rev_hex)
629{
630 int len = strlen(bisect_rev_hex);
631 const char *filename = git_path("BISECT_EXPECTED_REV");
632 int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
633
634 if (fd < 0)
635 die("could not create file '%s': %s",
636 filename, strerror(errno));
637
638 bisect_rev_hex[len] = '\n';
639 write_or_die(fd, bisect_rev_hex, len + 1);
640 bisect_rev_hex[len] = '\0';
641
642 if (close(fd) < 0)
643 die("closing file %s: %s", filename, strerror(errno));
644}
645
646static int bisect_checkout(char *bisect_rev_hex)
647{
648 int res;
649
650 mark_expected_rev(bisect_rev_hex);
651
652 argv_checkout[2] = bisect_rev_hex;
653 res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
654 if (res)
655 exit(res);
656
657 argv_show_branch[1] = bisect_rev_hex;
658 return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
659}
660
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CC
661static struct commit *get_commit_reference(const unsigned char *sha1)
662{
663 struct commit *r = lookup_commit_reference(sha1);
664 if (!r)
665 die("Not a valid commit name %s", sha1_to_hex(sha1));
666 return r;
667}
668
669static struct commit **get_bad_and_good_commits(int *rev_nr)
670{
671 int len = 1 + good_revs.sha1_nr;
672 struct commit **rev = xmalloc(len * sizeof(*rev));
673 int i, n = 0;
674
675 rev[n++] = get_commit_reference(current_bad_sha1);
676 for (i = 0; i < good_revs.sha1_nr; i++)
677 rev[n++] = get_commit_reference(good_revs.sha1[i]);
678 *rev_nr = n;
679
680 return rev;
681}
682
683static void handle_bad_merge_base(void)
684{
685 if (is_expected_rev(current_bad_sha1)) {
686 char *bad_hex = sha1_to_hex(current_bad_sha1);
687 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
688
689 fprintf(stderr, "The merge base %s is bad.\n"
690 "This means the bug has been fixed "
691 "between %s and [%s].\n",
692 bad_hex, bad_hex, good_hex);
693
694 exit(3);
695 }
696
697 fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
698 "git bisect cannot work properly in this case.\n"
699 "Maybe you mistake good and bad revs?\n");
700 exit(1);
701}
702
703void handle_skipped_merge_base(const unsigned char *mb)
704{
705 char *mb_hex = sha1_to_hex(mb);
706 char *bad_hex = sha1_to_hex(current_bad_sha1);
707 char *good_hex = join_sha1_array_hex(&good_revs, ' ');
708
709 fprintf(stderr, "Warning: the merge base between %s and [%s] "
710 "must be skipped.\n"
711 "So we cannot be sure the first bad commit is "
712 "between %s and %s.\n"
713 "We continue anyway.\n",
714 bad_hex, good_hex, mb_hex, bad_hex);
715 free(good_hex);
716}
717
718/*
719 * "check_merge_bases" checks that merge bases are not "bad".
720 *
721 * - If one is "bad", it means the user assumed something wrong
722 * and we must exit with a non 0 error code.
723 * - If one is "good", that's good, we have nothing to do.
724 * - If one is "skipped", we can't know but we should warn.
725 * - If we don't know, we should check it out and ask the user to test.
726 */
727static void check_merge_bases(void)
728{
729 struct commit_list *result;
730 int rev_nr;
731 struct commit **rev = get_bad_and_good_commits(&rev_nr);
732
733 result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
734
735 for (; result; result = result->next) {
736 const unsigned char *mb = result->item->object.sha1;
737 if (!hashcmp(mb, current_bad_sha1)) {
738 handle_bad_merge_base();
739 } else if (0 <= lookup_sha1_array(&good_revs, mb)) {
740 continue;
741 } else if (0 <= lookup_sha1_array(&skipped_revs, mb)) {
742 handle_skipped_merge_base(mb);
743 } else {
744 printf("Bisecting: a merge base must be tested\n");
745 exit(bisect_checkout(sha1_to_hex(mb)));
746 }
747 }
748
749 free(rev);
750 free_commit_list(result);
751}
752
2d938fc7 753static int check_ancestors(const char *prefix)
d937d4ac 754{
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755 struct rev_info revs;
756 struct object_array pending_copy;
757 int i, res;
d937d4ac 758
2d938fc7 759 bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
d937d4ac 760
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761 /* Save pending objects, so they can be cleaned up later. */
762 memset(&pending_copy, 0, sizeof(pending_copy));
763 for (i = 0; i < revs.pending.nr; i++)
764 add_object_array(revs.pending.objects[i].item,
765 revs.pending.objects[i].name,
766 &pending_copy);
767
768 bisect_common(&revs);
769 res = (revs.commits != NULL);
770
771 /* Clean up objects used, as they will be reused. */
772 for (i = 0; i < pending_copy.nr; i++) {
773 struct object *o = pending_copy.objects[i].item;
7a8e3895 774 clear_commit_marks((struct commit *)o, ALL_REV_FLAGS);
d937d4ac 775 }
d937d4ac 776
2d938fc7 777 return res;
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778}
779
780/*
781 * "check_good_are_ancestors_of_bad" checks that all "good" revs are
782 * ancestor of the "bad" rev.
783 *
784 * If that's not the case, we need to check the merge bases.
785 * If a merge base must be tested by the user, its source code will be
786 * checked out to be tested by the user and we will exit.
787 */
788static void check_good_are_ancestors_of_bad(const char *prefix)
789{
790 const char *filename = git_path("BISECT_ANCESTORS_OK");
791 struct stat st;
792 int fd;
793
794 if (!current_bad_sha1)
795 die("a bad revision is needed");
796
797 /* Check if file BISECT_ANCESTORS_OK exists. */
798 if (!stat(filename, &st) && S_ISREG(st.st_mode))
799 return;
800
801 /* Bisecting with no good rev is ok. */
802 if (good_revs.sha1_nr == 0)
803 return;
804
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805 /* Check if all good revs are ancestor of the bad rev. */
806 if (check_ancestors(prefix))
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807 check_merge_bases();
808
809 /* Create file BISECT_ANCESTORS_OK. */
810 fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
811 if (fd < 0)
812 warning("could not create file '%s': %s",
813 filename, strerror(errno));
814 else
815 close(fd);
816}
817
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818/*
819 * This does "git diff-tree --pretty COMMIT" without one fork+exec.
820 */
821static void show_diff_tree(const char *prefix, struct commit *commit)
822{
823 struct rev_info opt;
824
825 /* diff-tree init */
826 init_revisions(&opt, prefix);
827 git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
828 opt.abbrev = 0;
829 opt.diff = 1;
830
831 /* This is what "--pretty" does */
832 opt.verbose_header = 1;
833 opt.use_terminator = 0;
834 opt.commit_format = CMIT_FMT_DEFAULT;
835
836 /* diff-tree init */
837 if (!opt.diffopt.output_format)
838 opt.diffopt.output_format = DIFF_FORMAT_RAW;
839
840 log_tree_commit(&opt, commit);
841}
842
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843/*
844 * We use the convention that exiting with an exit code 10 means that
845 * the bisection process finished successfully.
846 * In this case the calling shell script should exit 0.
847 */
0871984d 848int bisect_next_all(const char *prefix)
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849{
850 struct rev_info revs;
851 struct commit_list *tried;
852 int reaches = 0, all = 0, nr;
853 const unsigned char *bisect_rev;
854 char bisect_rev_hex[41];
855
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856 if (read_bisect_refs())
857 die("reading bisect refs failed");
858
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859 check_good_are_ancestors_of_bad(prefix);
860
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861 bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
862 revs.limited = 1;
2b020695 863
a22347c6 864 bisect_common(&revs);
ef24c7ca 865
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866 revs.commits = find_bisection(revs.commits, &reaches, &all,
867 !!skipped_revs.sha1_nr);
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868 revs.commits = filter_skipped(revs.commits, &tried, 0);
869
870 if (!revs.commits) {
871 /*
872 * We should exit here only if the "bad"
873 * commit is also a "skip" commit.
874 */
875 exit_if_skipped_commits(tried, NULL);
876
877 printf("%s was both good and bad\n",
878 sha1_to_hex(current_bad_sha1));
879 exit(1);
880 }
881
882 bisect_rev = revs.commits->item->object.sha1;
883 memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
884
885 if (!hashcmp(bisect_rev, current_bad_sha1)) {
886 exit_if_skipped_commits(tried, current_bad_sha1);
887 printf("%s is first bad commit\n", bisect_rev_hex);
e22278c0 888 show_diff_tree(prefix, revs.commits->item);
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889 /* This means the bisection process succeeded. */
890 exit(10);
891 }
892
893 nr = all - reaches - 1;
894 printf("Bisecting: %d revisions left to test after this "
895 "(roughly %d steps)\n", nr, estimate_bisect_steps(all));
896
897 return bisect_checkout(bisect_rev_hex);
898}
899