Merge branch 'js/userdiff-php'
[git] / commit-reach.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "commit-graph.h"
4 #include "decorate.h"
5 #include "prio-queue.h"
6 #include "tree.h"
7 #include "ref-filter.h"
8 #include "revision.h"
9 #include "tag.h"
10 #include "commit-reach.h"
11
12 /* Remember to update object flag allocation in object.h */
13 #define PARENT1         (1u<<16)
14 #define PARENT2         (1u<<17)
15 #define STALE           (1u<<18)
16 #define RESULT          (1u<<19)
17
18 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
19
20 static int queue_has_nonstale(struct prio_queue *queue)
21 {
22         int i;
23         for (i = 0; i < queue->nr; i++) {
24                 struct commit *commit = queue->array[i].data;
25                 if (!(commit->object.flags & STALE))
26                         return 1;
27         }
28         return 0;
29 }
30
31 /* all input commits in one and twos[] must have been parsed! */
32 static struct commit_list *paint_down_to_common(struct repository *r,
33                                                 struct commit *one, int n,
34                                                 struct commit **twos,
35                                                 int min_generation)
36 {
37         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
38         struct commit_list *result = NULL;
39         int i;
40         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
41
42         if (!min_generation)
43                 queue.compare = compare_commits_by_commit_date;
44
45         one->object.flags |= PARENT1;
46         if (!n) {
47                 commit_list_append(one, &result);
48                 return result;
49         }
50         prio_queue_put(&queue, one);
51
52         for (i = 0; i < n; i++) {
53                 twos[i]->object.flags |= PARENT2;
54                 prio_queue_put(&queue, twos[i]);
55         }
56
57         while (queue_has_nonstale(&queue)) {
58                 struct commit *commit = prio_queue_get(&queue);
59                 struct commit_list *parents;
60                 int flags;
61                 uint32_t generation = commit_graph_generation(commit);
62
63                 if (min_generation && generation > last_gen)
64                         BUG("bad generation skip %8x > %8x at %s",
65                             generation, last_gen,
66                             oid_to_hex(&commit->object.oid));
67                 last_gen = generation;
68
69                 if (generation < min_generation)
70                         break;
71
72                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
73                 if (flags == (PARENT1 | PARENT2)) {
74                         if (!(commit->object.flags & RESULT)) {
75                                 commit->object.flags |= RESULT;
76                                 commit_list_insert_by_date(commit, &result);
77                         }
78                         /* Mark parents of a found merge stale */
79                         flags |= STALE;
80                 }
81                 parents = commit->parents;
82                 while (parents) {
83                         struct commit *p = parents->item;
84                         parents = parents->next;
85                         if ((p->object.flags & flags) == flags)
86                                 continue;
87                         if (repo_parse_commit(r, p))
88                                 return NULL;
89                         p->object.flags |= flags;
90                         prio_queue_put(&queue, p);
91                 }
92         }
93
94         clear_prio_queue(&queue);
95         return result;
96 }
97
98 static struct commit_list *merge_bases_many(struct repository *r,
99                                             struct commit *one, int n,
100                                             struct commit **twos)
101 {
102         struct commit_list *list = NULL;
103         struct commit_list *result = NULL;
104         int i;
105
106         for (i = 0; i < n; i++) {
107                 if (one == twos[i])
108                         /*
109                          * We do not mark this even with RESULT so we do not
110                          * have to clean it up.
111                          */
112                         return commit_list_insert(one, &result);
113         }
114
115         if (repo_parse_commit(r, one))
116                 return NULL;
117         for (i = 0; i < n; i++) {
118                 if (repo_parse_commit(r, twos[i]))
119                         return NULL;
120         }
121
122         list = paint_down_to_common(r, one, n, twos, 0);
123
124         while (list) {
125                 struct commit *commit = pop_commit(&list);
126                 if (!(commit->object.flags & STALE))
127                         commit_list_insert_by_date(commit, &result);
128         }
129         return result;
130 }
131
132 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
133 {
134         struct commit_list *i, *j, *k, *ret = NULL;
135
136         if (!in)
137                 return ret;
138
139         commit_list_insert(in->item, &ret);
140
141         for (i = in->next; i; i = i->next) {
142                 struct commit_list *new_commits = NULL, *end = NULL;
143
144                 for (j = ret; j; j = j->next) {
145                         struct commit_list *bases;
146                         bases = get_merge_bases(i->item, j->item);
147                         if (!new_commits)
148                                 new_commits = bases;
149                         else
150                                 end->next = bases;
151                         for (k = bases; k; k = k->next)
152                                 end = k;
153                 }
154                 ret = new_commits;
155         }
156         return ret;
157 }
158
159 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
160 {
161         /*
162          * Some commit in the array may be an ancestor of
163          * another commit.  Move such commit to the end of
164          * the array, and return the number of commits that
165          * are independent from each other.
166          */
167         struct commit **work;
168         unsigned char *redundant;
169         int *filled_index;
170         int i, j, filled;
171
172         work = xcalloc(cnt, sizeof(*work));
173         redundant = xcalloc(cnt, 1);
174         ALLOC_ARRAY(filled_index, cnt - 1);
175
176         for (i = 0; i < cnt; i++)
177                 repo_parse_commit(r, array[i]);
178         for (i = 0; i < cnt; i++) {
179                 struct commit_list *common;
180                 uint32_t min_generation = commit_graph_generation(array[i]);
181
182                 if (redundant[i])
183                         continue;
184                 for (j = filled = 0; j < cnt; j++) {
185                         uint32_t curr_generation;
186                         if (i == j || redundant[j])
187                                 continue;
188                         filled_index[filled] = j;
189                         work[filled++] = array[j];
190
191                         curr_generation = commit_graph_generation(array[j]);
192                         if (curr_generation < min_generation)
193                                 min_generation = curr_generation;
194                 }
195                 common = paint_down_to_common(r, array[i], filled,
196                                               work, min_generation);
197                 if (array[i]->object.flags & PARENT2)
198                         redundant[i] = 1;
199                 for (j = 0; j < filled; j++)
200                         if (work[j]->object.flags & PARENT1)
201                                 redundant[filled_index[j]] = 1;
202                 clear_commit_marks(array[i], all_flags);
203                 clear_commit_marks_many(filled, work, all_flags);
204                 free_commit_list(common);
205         }
206
207         /* Now collect the result */
208         COPY_ARRAY(work, array, cnt);
209         for (i = filled = 0; i < cnt; i++)
210                 if (!redundant[i])
211                         array[filled++] = work[i];
212         for (j = filled, i = 0; i < cnt; i++)
213                 if (redundant[i])
214                         array[j++] = work[i];
215         free(work);
216         free(redundant);
217         free(filled_index);
218         return filled;
219 }
220
221 static struct commit_list *get_merge_bases_many_0(struct repository *r,
222                                                   struct commit *one,
223                                                   int n,
224                                                   struct commit **twos,
225                                                   int cleanup)
226 {
227         struct commit_list *list;
228         struct commit **rslt;
229         struct commit_list *result;
230         int cnt, i;
231
232         result = merge_bases_many(r, one, n, twos);
233         for (i = 0; i < n; i++) {
234                 if (one == twos[i])
235                         return result;
236         }
237         if (!result || !result->next) {
238                 if (cleanup) {
239                         clear_commit_marks(one, all_flags);
240                         clear_commit_marks_many(n, twos, all_flags);
241                 }
242                 return result;
243         }
244
245         /* There are more than one */
246         cnt = commit_list_count(result);
247         rslt = xcalloc(cnt, sizeof(*rslt));
248         for (list = result, i = 0; list; list = list->next)
249                 rslt[i++] = list->item;
250         free_commit_list(result);
251
252         clear_commit_marks(one, all_flags);
253         clear_commit_marks_many(n, twos, all_flags);
254
255         cnt = remove_redundant(r, rslt, cnt);
256         result = NULL;
257         for (i = 0; i < cnt; i++)
258                 commit_list_insert_by_date(rslt[i], &result);
259         free(rslt);
260         return result;
261 }
262
263 struct commit_list *repo_get_merge_bases_many(struct repository *r,
264                                               struct commit *one,
265                                               int n,
266                                               struct commit **twos)
267 {
268         return get_merge_bases_many_0(r, one, n, twos, 1);
269 }
270
271 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
272                                                     struct commit *one,
273                                                     int n,
274                                                     struct commit **twos)
275 {
276         return get_merge_bases_many_0(r, one, n, twos, 0);
277 }
278
279 struct commit_list *repo_get_merge_bases(struct repository *r,
280                                          struct commit *one,
281                                          struct commit *two)
282 {
283         return get_merge_bases_many_0(r, one, 1, &two, 1);
284 }
285
286 /*
287  * Is "commit" a descendant of one of the elements on the "with_commit" list?
288  */
289 int repo_is_descendant_of(struct repository *r,
290                           struct commit *commit,
291                           struct commit_list *with_commit)
292 {
293         if (!with_commit)
294                 return 1;
295
296         if (generation_numbers_enabled(the_repository)) {
297                 struct commit_list *from_list = NULL;
298                 int result;
299                 commit_list_insert(commit, &from_list);
300                 result = can_all_from_reach(from_list, with_commit, 0);
301                 free_commit_list(from_list);
302                 return result;
303         } else {
304                 while (with_commit) {
305                         struct commit *other;
306
307                         other = with_commit->item;
308                         with_commit = with_commit->next;
309                         if (repo_in_merge_bases_many(r, other, 1, &commit))
310                                 return 1;
311                 }
312                 return 0;
313         }
314 }
315
316 /*
317  * Is "commit" an ancestor of one of the "references"?
318  */
319 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
320                              int nr_reference, struct commit **reference)
321 {
322         struct commit_list *bases;
323         int ret = 0, i;
324         uint32_t generation, max_generation = GENERATION_NUMBER_ZERO;
325
326         if (repo_parse_commit(r, commit))
327                 return ret;
328         for (i = 0; i < nr_reference; i++) {
329                 if (repo_parse_commit(r, reference[i]))
330                         return ret;
331
332                 generation = commit_graph_generation(reference[i]);
333                 if (generation > max_generation)
334                         max_generation = generation;
335         }
336
337         generation = commit_graph_generation(commit);
338         if (generation > max_generation)
339                 return ret;
340
341         bases = paint_down_to_common(r, commit,
342                                      nr_reference, reference,
343                                      generation);
344         if (commit->object.flags & PARENT2)
345                 ret = 1;
346         clear_commit_marks(commit, all_flags);
347         clear_commit_marks_many(nr_reference, reference, all_flags);
348         free_commit_list(bases);
349         return ret;
350 }
351
352 /*
353  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
354  */
355 int repo_in_merge_bases(struct repository *r,
356                         struct commit *commit,
357                         struct commit *reference)
358 {
359         int res;
360         struct commit_list *list = NULL;
361         struct commit_list **next = &list;
362
363         next = commit_list_append(commit, next);
364         res = repo_is_descendant_of(r, reference, list);
365         free_commit_list(list);
366
367         return res;
368 }
369
370 struct commit_list *reduce_heads(struct commit_list *heads)
371 {
372         struct commit_list *p;
373         struct commit_list *result = NULL, **tail = &result;
374         struct commit **array;
375         int num_head, i;
376
377         if (!heads)
378                 return NULL;
379
380         /* Uniquify */
381         for (p = heads; p; p = p->next)
382                 p->item->object.flags &= ~STALE;
383         for (p = heads, num_head = 0; p; p = p->next) {
384                 if (p->item->object.flags & STALE)
385                         continue;
386                 p->item->object.flags |= STALE;
387                 num_head++;
388         }
389         array = xcalloc(num_head, sizeof(*array));
390         for (p = heads, i = 0; p; p = p->next) {
391                 if (p->item->object.flags & STALE) {
392                         array[i++] = p->item;
393                         p->item->object.flags &= ~STALE;
394                 }
395         }
396         num_head = remove_redundant(the_repository, array, num_head);
397         for (i = 0; i < num_head; i++)
398                 tail = &commit_list_insert(array[i], tail)->next;
399         free(array);
400         return result;
401 }
402
403 void reduce_heads_replace(struct commit_list **heads)
404 {
405         struct commit_list *result = reduce_heads(*heads);
406         free_commit_list(*heads);
407         *heads = result;
408 }
409
410 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
411 {
412         struct object *o;
413         struct commit *old_commit, *new_commit;
414         struct commit_list *old_commit_list = NULL;
415         int ret;
416
417         /*
418          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
419          * old_commit.  Otherwise we require --force.
420          */
421         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
422                       NULL, 0);
423         if (!o || o->type != OBJ_COMMIT)
424                 return 0;
425         old_commit = (struct commit *) o;
426
427         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
428                       NULL, 0);
429         if (!o || o->type != OBJ_COMMIT)
430                 return 0;
431         new_commit = (struct commit *) o;
432
433         if (parse_commit(new_commit) < 0)
434                 return 0;
435
436         commit_list_insert(old_commit, &old_commit_list);
437         ret = repo_is_descendant_of(the_repository,
438                                     new_commit, old_commit_list);
439         free_commit_list(old_commit_list);
440         return ret;
441 }
442
443 /*
444  * Mimicking the real stack, this stack lives on the heap, avoiding stack
445  * overflows.
446  *
447  * At each recursion step, the stack items points to the commits whose
448  * ancestors are to be inspected.
449  */
450 struct contains_stack {
451         int nr, alloc;
452         struct contains_stack_entry {
453                 struct commit *commit;
454                 struct commit_list *parents;
455         } *contains_stack;
456 };
457
458 static int in_commit_list(const struct commit_list *want, struct commit *c)
459 {
460         for (; want; want = want->next)
461                 if (oideq(&want->item->object.oid, &c->object.oid))
462                         return 1;
463         return 0;
464 }
465
466 /*
467  * Test whether the candidate is contained in the list.
468  * Do not recurse to find out, though, but return -1 if inconclusive.
469  */
470 static enum contains_result contains_test(struct commit *candidate,
471                                           const struct commit_list *want,
472                                           struct contains_cache *cache,
473                                           uint32_t cutoff)
474 {
475         enum contains_result *cached = contains_cache_at(cache, candidate);
476
477         /* If we already have the answer cached, return that. */
478         if (*cached)
479                 return *cached;
480
481         /* or are we it? */
482         if (in_commit_list(want, candidate)) {
483                 *cached = CONTAINS_YES;
484                 return CONTAINS_YES;
485         }
486
487         /* Otherwise, we don't know; prepare to recurse */
488         parse_commit_or_die(candidate);
489
490         if (commit_graph_generation(candidate) < cutoff)
491                 return CONTAINS_NO;
492
493         return CONTAINS_UNKNOWN;
494 }
495
496 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
497 {
498         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
499         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
500         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
501 }
502
503 static enum contains_result contains_tag_algo(struct commit *candidate,
504                                               const struct commit_list *want,
505                                               struct contains_cache *cache)
506 {
507         struct contains_stack contains_stack = { 0, 0, NULL };
508         enum contains_result result;
509         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
510         const struct commit_list *p;
511
512         for (p = want; p; p = p->next) {
513                 uint32_t generation;
514                 struct commit *c = p->item;
515                 load_commit_graph_info(the_repository, c);
516                 generation = commit_graph_generation(c);
517                 if (generation < cutoff)
518                         cutoff = generation;
519         }
520
521         result = contains_test(candidate, want, cache, cutoff);
522         if (result != CONTAINS_UNKNOWN)
523                 return result;
524
525         push_to_contains_stack(candidate, &contains_stack);
526         while (contains_stack.nr) {
527                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
528                 struct commit *commit = entry->commit;
529                 struct commit_list *parents = entry->parents;
530
531                 if (!parents) {
532                         *contains_cache_at(cache, commit) = CONTAINS_NO;
533                         contains_stack.nr--;
534                 }
535                 /*
536                  * If we just popped the stack, parents->item has been marked,
537                  * therefore contains_test will return a meaningful yes/no.
538                  */
539                 else switch (contains_test(parents->item, want, cache, cutoff)) {
540                 case CONTAINS_YES:
541                         *contains_cache_at(cache, commit) = CONTAINS_YES;
542                         contains_stack.nr--;
543                         break;
544                 case CONTAINS_NO:
545                         entry->parents = parents->next;
546                         break;
547                 case CONTAINS_UNKNOWN:
548                         push_to_contains_stack(parents->item, &contains_stack);
549                         break;
550                 }
551         }
552         free(contains_stack.contains_stack);
553         return contains_test(candidate, want, cache, cutoff);
554 }
555
556 int commit_contains(struct ref_filter *filter, struct commit *commit,
557                     struct commit_list *list, struct contains_cache *cache)
558 {
559         if (filter->with_commit_tag_algo)
560                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
561         return repo_is_descendant_of(the_repository, commit, list);
562 }
563
564 static int compare_commits_by_gen(const void *_a, const void *_b)
565 {
566         const struct commit *a = *(const struct commit * const *)_a;
567         const struct commit *b = *(const struct commit * const *)_b;
568
569         uint32_t generation_a = commit_graph_generation(a);
570         uint32_t generation_b = commit_graph_generation(b);
571
572         if (generation_a < generation_b)
573                 return -1;
574         if (generation_a > generation_b)
575                 return 1;
576         return 0;
577 }
578
579 int can_all_from_reach_with_flag(struct object_array *from,
580                                  unsigned int with_flag,
581                                  unsigned int assign_flag,
582                                  time_t min_commit_date,
583                                  uint32_t min_generation)
584 {
585         struct commit **list = NULL;
586         int i;
587         int nr_commits;
588         int result = 1;
589
590         ALLOC_ARRAY(list, from->nr);
591         nr_commits = 0;
592         for (i = 0; i < from->nr; i++) {
593                 struct object *from_one = from->objects[i].item;
594
595                 if (!from_one || from_one->flags & assign_flag)
596                         continue;
597
598                 from_one = deref_tag(the_repository, from_one,
599                                      "a from object", 0);
600                 if (!from_one || from_one->type != OBJ_COMMIT) {
601                         /*
602                          * no way to tell if this is reachable by
603                          * looking at the ancestry chain alone, so
604                          * leave a note to ourselves not to worry about
605                          * this object anymore.
606                          */
607                         from->objects[i].item->flags |= assign_flag;
608                         continue;
609                 }
610
611                 list[nr_commits] = (struct commit *)from_one;
612                 if (parse_commit(list[nr_commits]) ||
613                     commit_graph_generation(list[nr_commits]) < min_generation) {
614                         result = 0;
615                         goto cleanup;
616                 }
617
618                 nr_commits++;
619         }
620
621         QSORT(list, nr_commits, compare_commits_by_gen);
622
623         for (i = 0; i < nr_commits; i++) {
624                 /* DFS from list[i] */
625                 struct commit_list *stack = NULL;
626
627                 list[i]->object.flags |= assign_flag;
628                 commit_list_insert(list[i], &stack);
629
630                 while (stack) {
631                         struct commit_list *parent;
632
633                         if (stack->item->object.flags & (with_flag | RESULT)) {
634                                 pop_commit(&stack);
635                                 if (stack)
636                                         stack->item->object.flags |= RESULT;
637                                 continue;
638                         }
639
640                         for (parent = stack->item->parents; parent; parent = parent->next) {
641                                 if (parent->item->object.flags & (with_flag | RESULT))
642                                         stack->item->object.flags |= RESULT;
643
644                                 if (!(parent->item->object.flags & assign_flag)) {
645                                         parent->item->object.flags |= assign_flag;
646
647                                         if (parse_commit(parent->item) ||
648                                             parent->item->date < min_commit_date ||
649                                             commit_graph_generation(parent->item) < min_generation)
650                                                 continue;
651
652                                         commit_list_insert(parent->item, &stack);
653                                         break;
654                                 }
655                         }
656
657                         if (!parent)
658                                 pop_commit(&stack);
659                 }
660
661                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
662                         result = 0;
663                         goto cleanup;
664                 }
665         }
666
667 cleanup:
668         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
669         free(list);
670
671         for (i = 0; i < from->nr; i++)
672                 from->objects[i].item->flags &= ~assign_flag;
673
674         return result;
675 }
676
677 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
678                        int cutoff_by_min_date)
679 {
680         struct object_array from_objs = OBJECT_ARRAY_INIT;
681         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
682         struct commit_list *from_iter = from, *to_iter = to;
683         int result;
684         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
685
686         while (from_iter) {
687                 add_object_array(&from_iter->item->object, NULL, &from_objs);
688
689                 if (!parse_commit(from_iter->item)) {
690                         uint32_t generation;
691                         if (from_iter->item->date < min_commit_date)
692                                 min_commit_date = from_iter->item->date;
693
694                         generation = commit_graph_generation(from_iter->item);
695                         if (generation < min_generation)
696                                 min_generation = generation;
697                 }
698
699                 from_iter = from_iter->next;
700         }
701
702         while (to_iter) {
703                 if (!parse_commit(to_iter->item)) {
704                         uint32_t generation;
705                         if (to_iter->item->date < min_commit_date)
706                                 min_commit_date = to_iter->item->date;
707
708                         generation = commit_graph_generation(to_iter->item);
709                         if (generation < min_generation)
710                                 min_generation = generation;
711                 }
712
713                 to_iter->item->object.flags |= PARENT2;
714
715                 to_iter = to_iter->next;
716         }
717
718         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
719                                               min_commit_date, min_generation);
720
721         while (from) {
722                 clear_commit_marks(from->item, PARENT1);
723                 from = from->next;
724         }
725
726         while (to) {
727                 clear_commit_marks(to->item, PARENT2);
728                 to = to->next;
729         }
730
731         object_array_clear(&from_objs);
732         return result;
733 }
734
735 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
736                                          struct commit **to, int nr_to,
737                                          unsigned int reachable_flag)
738 {
739         struct commit **item;
740         struct commit *current;
741         struct commit_list *found_commits = NULL;
742         struct commit **to_last = to + nr_to;
743         struct commit **from_last = from + nr_from;
744         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
745         int num_to_find = 0;
746
747         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
748
749         for (item = to; item < to_last; item++) {
750                 uint32_t generation;
751                 struct commit *c = *item;
752
753                 parse_commit(c);
754                 generation = commit_graph_generation(c);
755                 if (generation < min_generation)
756                         min_generation = generation;
757
758                 if (!(c->object.flags & PARENT1)) {
759                         c->object.flags |= PARENT1;
760                         num_to_find++;
761                 }
762         }
763
764         for (item = from; item < from_last; item++) {
765                 struct commit *c = *item;
766                 if (!(c->object.flags & PARENT2)) {
767                         c->object.flags |= PARENT2;
768                         parse_commit(c);
769
770                         prio_queue_put(&queue, *item);
771                 }
772         }
773
774         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
775                 struct commit_list *parents;
776
777                 if (current->object.flags & PARENT1) {
778                         current->object.flags &= ~PARENT1;
779                         current->object.flags |= reachable_flag;
780                         commit_list_insert(current, &found_commits);
781                         num_to_find--;
782                 }
783
784                 for (parents = current->parents; parents; parents = parents->next) {
785                         struct commit *p = parents->item;
786
787                         parse_commit(p);
788
789                         if (commit_graph_generation(p) < min_generation)
790                                 continue;
791
792                         if (p->object.flags & PARENT2)
793                                 continue;
794
795                         p->object.flags |= PARENT2;
796                         prio_queue_put(&queue, p);
797                 }
798         }
799
800         clear_commit_marks_many(nr_to, to, PARENT1);
801         clear_commit_marks_many(nr_from, from, PARENT2);
802
803         return found_commits;
804 }