Merge branch 'maint'
[git] / revision.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "refs.h"
8 #include "revision.h"
9 #include "graph.h"
10 #include "grep.h"
11 #include "reflog-walk.h"
12 #include "patch-ids.h"
13 #include "decorate.h"
14 #include "log-tree.h"
15 #include "string-list.h"
16
17 volatile show_early_output_fn_t show_early_output;
18
19 char *path_name(const struct name_path *path, const char *name)
20 {
21         const struct name_path *p;
22         char *n, *m;
23         int nlen = strlen(name);
24         int len = nlen + 1;
25
26         for (p = path; p; p = p->up) {
27                 if (p->elem_len)
28                         len += p->elem_len + 1;
29         }
30         n = xmalloc(len);
31         m = n + len - (nlen + 1);
32         strcpy(m, name);
33         for (p = path; p; p = p->up) {
34                 if (p->elem_len) {
35                         m -= p->elem_len + 1;
36                         memcpy(m, p->elem, p->elem_len);
37                         m[p->elem_len] = '/';
38                 }
39         }
40         return n;
41 }
42
43 void add_object(struct object *obj,
44                 struct object_array *p,
45                 struct name_path *path,
46                 const char *name)
47 {
48         add_object_array(obj, path_name(path, name), p);
49 }
50
51 static void mark_blob_uninteresting(struct blob *blob)
52 {
53         if (!blob)
54                 return;
55         if (blob->object.flags & UNINTERESTING)
56                 return;
57         blob->object.flags |= UNINTERESTING;
58 }
59
60 void mark_tree_uninteresting(struct tree *tree)
61 {
62         struct tree_desc desc;
63         struct name_entry entry;
64         struct object *obj = &tree->object;
65
66         if (!tree)
67                 return;
68         if (obj->flags & UNINTERESTING)
69                 return;
70         obj->flags |= UNINTERESTING;
71         if (!has_sha1_file(obj->sha1))
72                 return;
73         if (parse_tree(tree) < 0)
74                 die("bad tree %s", sha1_to_hex(obj->sha1));
75
76         init_tree_desc(&desc, tree->buffer, tree->size);
77         while (tree_entry(&desc, &entry)) {
78                 switch (object_type(entry.mode)) {
79                 case OBJ_TREE:
80                         mark_tree_uninteresting(lookup_tree(entry.sha1));
81                         break;
82                 case OBJ_BLOB:
83                         mark_blob_uninteresting(lookup_blob(entry.sha1));
84                         break;
85                 default:
86                         /* Subproject commit - not in this repository */
87                         break;
88                 }
89         }
90
91         /*
92          * We don't care about the tree any more
93          * after it has been marked uninteresting.
94          */
95         free(tree->buffer);
96         tree->buffer = NULL;
97 }
98
99 void mark_parents_uninteresting(struct commit *commit)
100 {
101         struct commit_list *parents = commit->parents;
102
103         while (parents) {
104                 struct commit *commit = parents->item;
105                 if (!(commit->object.flags & UNINTERESTING)) {
106                         commit->object.flags |= UNINTERESTING;
107
108                         /*
109                          * Normally we haven't parsed the parent
110                          * yet, so we won't have a parent of a parent
111                          * here. However, it may turn out that we've
112                          * reached this commit some other way (where it
113                          * wasn't uninteresting), in which case we need
114                          * to mark its parents recursively too..
115                          */
116                         if (commit->parents)
117                                 mark_parents_uninteresting(commit);
118                 }
119
120                 /*
121                  * A missing commit is ok iff its parent is marked
122                  * uninteresting.
123                  *
124                  * We just mark such a thing parsed, so that when
125                  * it is popped next time around, we won't be trying
126                  * to parse it and get an error.
127                  */
128                 if (!has_sha1_file(commit->object.sha1))
129                         commit->object.parsed = 1;
130                 parents = parents->next;
131         }
132 }
133
134 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
135 {
136         if (revs->no_walk && (obj->flags & UNINTERESTING))
137                 revs->no_walk = 0;
138         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
139                 struct strbuf buf = STRBUF_INIT;
140                 int len = interpret_branch_name(name, &buf);
141                 int st;
142
143                 if (0 < len && name[len] && buf.len)
144                         strbuf_addstr(&buf, name + len);
145                 st = add_reflog_for_walk(revs->reflog_info,
146                                          (struct commit *)obj,
147                                          buf.buf[0] ? buf.buf: name);
148                 strbuf_release(&buf);
149                 if (st)
150                         return;
151         }
152         add_object_array_with_mode(obj, name, &revs->pending, mode);
153 }
154
155 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
156 {
157         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
158 }
159
160 void add_head_to_pending(struct rev_info *revs)
161 {
162         unsigned char sha1[20];
163         struct object *obj;
164         if (get_sha1("HEAD", sha1))
165                 return;
166         obj = parse_object(sha1);
167         if (!obj)
168                 return;
169         add_pending_object(revs, obj, "HEAD");
170 }
171
172 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
173 {
174         struct object *object;
175
176         object = parse_object(sha1);
177         if (!object)
178                 die("bad object %s", name);
179         object->flags |= flags;
180         return object;
181 }
182
183 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
184 {
185         unsigned long flags = object->flags;
186
187         /*
188          * Tag object? Look what it points to..
189          */
190         while (object->type == OBJ_TAG) {
191                 struct tag *tag = (struct tag *) object;
192                 if (revs->tag_objects && !(flags & UNINTERESTING))
193                         add_pending_object(revs, object, tag->tag);
194                 if (!tag->tagged)
195                         die("bad tag");
196                 object = parse_object(tag->tagged->sha1);
197                 if (!object) {
198                         if (flags & UNINTERESTING)
199                                 return NULL;
200                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
201                 }
202         }
203
204         /*
205          * Commit object? Just return it, we'll do all the complex
206          * reachability crud.
207          */
208         if (object->type == OBJ_COMMIT) {
209                 struct commit *commit = (struct commit *)object;
210                 if (parse_commit(commit) < 0)
211                         die("unable to parse commit %s", name);
212                 if (flags & UNINTERESTING) {
213                         commit->object.flags |= UNINTERESTING;
214                         mark_parents_uninteresting(commit);
215                         revs->limited = 1;
216                 }
217                 if (revs->show_source && !commit->util)
218                         commit->util = (void *) name;
219                 return commit;
220         }
221
222         /*
223          * Tree object? Either mark it uninteresting, or add it
224          * to the list of objects to look at later..
225          */
226         if (object->type == OBJ_TREE) {
227                 struct tree *tree = (struct tree *)object;
228                 if (!revs->tree_objects)
229                         return NULL;
230                 if (flags & UNINTERESTING) {
231                         mark_tree_uninteresting(tree);
232                         return NULL;
233                 }
234                 add_pending_object(revs, object, "");
235                 return NULL;
236         }
237
238         /*
239          * Blob object? You know the drill by now..
240          */
241         if (object->type == OBJ_BLOB) {
242                 struct blob *blob = (struct blob *)object;
243                 if (!revs->blob_objects)
244                         return NULL;
245                 if (flags & UNINTERESTING) {
246                         mark_blob_uninteresting(blob);
247                         return NULL;
248                 }
249                 add_pending_object(revs, object, "");
250                 return NULL;
251         }
252         die("%s is unknown object", name);
253 }
254
255 static int everybody_uninteresting(struct commit_list *orig)
256 {
257         struct commit_list *list = orig;
258         while (list) {
259                 struct commit *commit = list->item;
260                 list = list->next;
261                 if (commit->object.flags & UNINTERESTING)
262                         continue;
263                 return 0;
264         }
265         return 1;
266 }
267
268 /*
269  * The goal is to get REV_TREE_NEW as the result only if the
270  * diff consists of all '+' (and no other changes), REV_TREE_OLD
271  * if the whole diff is removal of old data, and otherwise
272  * REV_TREE_DIFFERENT (of course if the trees are the same we
273  * want REV_TREE_SAME).
274  * That means that once we get to REV_TREE_DIFFERENT, we do not
275  * have to look any further.
276  */
277 static int tree_difference = REV_TREE_SAME;
278
279 static void file_add_remove(struct diff_options *options,
280                     int addremove, unsigned mode,
281                     const unsigned char *sha1,
282                     const char *fullpath, unsigned dirty_submodule)
283 {
284         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
285
286         tree_difference |= diff;
287         if (tree_difference == REV_TREE_DIFFERENT)
288                 DIFF_OPT_SET(options, HAS_CHANGES);
289 }
290
291 static void file_change(struct diff_options *options,
292                  unsigned old_mode, unsigned new_mode,
293                  const unsigned char *old_sha1,
294                  const unsigned char *new_sha1,
295                  const char *fullpath,
296                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
297 {
298         tree_difference = REV_TREE_DIFFERENT;
299         DIFF_OPT_SET(options, HAS_CHANGES);
300 }
301
302 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
303 {
304         struct tree *t1 = parent->tree;
305         struct tree *t2 = commit->tree;
306
307         if (!t1)
308                 return REV_TREE_NEW;
309         if (!t2)
310                 return REV_TREE_OLD;
311
312         if (revs->simplify_by_decoration) {
313                 /*
314                  * If we are simplifying by decoration, then the commit
315                  * is worth showing if it has a tag pointing at it.
316                  */
317                 if (lookup_decoration(&name_decoration, &commit->object))
318                         return REV_TREE_DIFFERENT;
319                 /*
320                  * A commit that is not pointed by a tag is uninteresting
321                  * if we are not limited by path.  This means that you will
322                  * see the usual "commits that touch the paths" plus any
323                  * tagged commit by specifying both --simplify-by-decoration
324                  * and pathspec.
325                  */
326                 if (!revs->prune_data)
327                         return REV_TREE_SAME;
328         }
329
330         tree_difference = REV_TREE_SAME;
331         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
332         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
333                            &revs->pruning) < 0)
334                 return REV_TREE_DIFFERENT;
335         return tree_difference;
336 }
337
338 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
339 {
340         int retval;
341         void *tree;
342         unsigned long size;
343         struct tree_desc empty, real;
344         struct tree *t1 = commit->tree;
345
346         if (!t1)
347                 return 0;
348
349         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
350         if (!tree)
351                 return 0;
352         init_tree_desc(&real, tree, size);
353         init_tree_desc(&empty, "", 0);
354
355         tree_difference = REV_TREE_SAME;
356         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
357         retval = diff_tree(&empty, &real, "", &revs->pruning);
358         free(tree);
359
360         return retval >= 0 && (tree_difference == REV_TREE_SAME);
361 }
362
363 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
364 {
365         struct commit_list **pp, *parent;
366         int tree_changed = 0, tree_same = 0;
367
368         /*
369          * If we don't do pruning, everything is interesting
370          */
371         if (!revs->prune)
372                 return;
373
374         if (!commit->tree)
375                 return;
376
377         if (!commit->parents) {
378                 if (rev_same_tree_as_empty(revs, commit))
379                         commit->object.flags |= TREESAME;
380                 return;
381         }
382
383         /*
384          * Normal non-merge commit? If we don't want to make the
385          * history dense, we consider it always to be a change..
386          */
387         if (!revs->dense && !commit->parents->next)
388                 return;
389
390         pp = &commit->parents;
391         while ((parent = *pp) != NULL) {
392                 struct commit *p = parent->item;
393
394                 if (parse_commit(p) < 0)
395                         die("cannot simplify commit %s (because of %s)",
396                             sha1_to_hex(commit->object.sha1),
397                             sha1_to_hex(p->object.sha1));
398                 switch (rev_compare_tree(revs, p, commit)) {
399                 case REV_TREE_SAME:
400                         tree_same = 1;
401                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
402                                 /* Even if a merge with an uninteresting
403                                  * side branch brought the entire change
404                                  * we are interested in, we do not want
405                                  * to lose the other branches of this
406                                  * merge, so we just keep going.
407                                  */
408                                 pp = &parent->next;
409                                 continue;
410                         }
411                         parent->next = NULL;
412                         commit->parents = parent;
413                         commit->object.flags |= TREESAME;
414                         return;
415
416                 case REV_TREE_NEW:
417                         if (revs->remove_empty_trees &&
418                             rev_same_tree_as_empty(revs, p)) {
419                                 /* We are adding all the specified
420                                  * paths from this parent, so the
421                                  * history beyond this parent is not
422                                  * interesting.  Remove its parents
423                                  * (they are grandparents for us).
424                                  * IOW, we pretend this parent is a
425                                  * "root" commit.
426                                  */
427                                 if (parse_commit(p) < 0)
428                                         die("cannot simplify commit %s (invalid %s)",
429                                             sha1_to_hex(commit->object.sha1),
430                                             sha1_to_hex(p->object.sha1));
431                                 p->parents = NULL;
432                         }
433                 /* fallthrough */
434                 case REV_TREE_OLD:
435                 case REV_TREE_DIFFERENT:
436                         tree_changed = 1;
437                         pp = &parent->next;
438                         continue;
439                 }
440                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
441         }
442         if (tree_changed && !tree_same)
443                 return;
444         commit->object.flags |= TREESAME;
445 }
446
447 static void insert_by_date_cached(struct commit *p, struct commit_list **head,
448                     struct commit_list *cached_base, struct commit_list **cache)
449 {
450         struct commit_list *new_entry;
451
452         if (cached_base && p->date < cached_base->item->date)
453                 new_entry = insert_by_date(p, &cached_base->next);
454         else
455                 new_entry = insert_by_date(p, head);
456
457         if (cache && (!*cache || p->date < (*cache)->item->date))
458                 *cache = new_entry;
459 }
460
461 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
462                     struct commit_list **list, struct commit_list **cache_ptr)
463 {
464         struct commit_list *parent = commit->parents;
465         unsigned left_flag;
466         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
467
468         if (commit->object.flags & ADDED)
469                 return 0;
470         commit->object.flags |= ADDED;
471
472         /*
473          * If the commit is uninteresting, don't try to
474          * prune parents - we want the maximal uninteresting
475          * set.
476          *
477          * Normally we haven't parsed the parent
478          * yet, so we won't have a parent of a parent
479          * here. However, it may turn out that we've
480          * reached this commit some other way (where it
481          * wasn't uninteresting), in which case we need
482          * to mark its parents recursively too..
483          */
484         if (commit->object.flags & UNINTERESTING) {
485                 while (parent) {
486                         struct commit *p = parent->item;
487                         parent = parent->next;
488                         if (p)
489                                 p->object.flags |= UNINTERESTING;
490                         if (parse_commit(p) < 0)
491                                 continue;
492                         if (p->parents)
493                                 mark_parents_uninteresting(p);
494                         if (p->object.flags & SEEN)
495                                 continue;
496                         p->object.flags |= SEEN;
497                         insert_by_date_cached(p, list, cached_base, cache_ptr);
498                 }
499                 return 0;
500         }
501
502         /*
503          * Ok, the commit wasn't uninteresting. Try to
504          * simplify the commit history and find the parent
505          * that has no differences in the path set if one exists.
506          */
507         try_to_simplify_commit(revs, commit);
508
509         if (revs->no_walk)
510                 return 0;
511
512         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
513
514         for (parent = commit->parents; parent; parent = parent->next) {
515                 struct commit *p = parent->item;
516
517                 if (parse_commit(p) < 0)
518                         return -1;
519                 if (revs->show_source && !p->util)
520                         p->util = commit->util;
521                 p->object.flags |= left_flag;
522                 if (!(p->object.flags & SEEN)) {
523                         p->object.flags |= SEEN;
524                         insert_by_date_cached(p, list, cached_base, cache_ptr);
525                 }
526                 if (revs->first_parent_only)
527                         break;
528         }
529         return 0;
530 }
531
532 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
533 {
534         struct commit_list *p;
535         int left_count = 0, right_count = 0;
536         int left_first;
537         struct patch_ids ids;
538
539         /* First count the commits on the left and on the right */
540         for (p = list; p; p = p->next) {
541                 struct commit *commit = p->item;
542                 unsigned flags = commit->object.flags;
543                 if (flags & BOUNDARY)
544                         ;
545                 else if (flags & SYMMETRIC_LEFT)
546                         left_count++;
547                 else
548                         right_count++;
549         }
550
551         if (!left_count || !right_count)
552                 return;
553
554         left_first = left_count < right_count;
555         init_patch_ids(&ids);
556         if (revs->diffopt.nr_paths) {
557                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
558                 ids.diffopts.paths = revs->diffopt.paths;
559                 ids.diffopts.pathlens = revs->diffopt.pathlens;
560         }
561
562         /* Compute patch-ids for one side */
563         for (p = list; p; p = p->next) {
564                 struct commit *commit = p->item;
565                 unsigned flags = commit->object.flags;
566
567                 if (flags & BOUNDARY)
568                         continue;
569                 /*
570                  * If we have fewer left, left_first is set and we omit
571                  * commits on the right branch in this loop.  If we have
572                  * fewer right, we skip the left ones.
573                  */
574                 if (left_first != !!(flags & SYMMETRIC_LEFT))
575                         continue;
576                 commit->util = add_commit_patch_id(commit, &ids);
577         }
578
579         /* Check the other side */
580         for (p = list; p; p = p->next) {
581                 struct commit *commit = p->item;
582                 struct patch_id *id;
583                 unsigned flags = commit->object.flags;
584
585                 if (flags & BOUNDARY)
586                         continue;
587                 /*
588                  * If we have fewer left, left_first is set and we omit
589                  * commits on the left branch in this loop.
590                  */
591                 if (left_first == !!(flags & SYMMETRIC_LEFT))
592                         continue;
593
594                 /*
595                  * Have we seen the same patch id?
596                  */
597                 id = has_commit_patch_id(commit, &ids);
598                 if (!id)
599                         continue;
600                 id->seen = 1;
601                 commit->object.flags |= SHOWN;
602         }
603
604         /* Now check the original side for seen ones */
605         for (p = list; p; p = p->next) {
606                 struct commit *commit = p->item;
607                 struct patch_id *ent;
608
609                 ent = commit->util;
610                 if (!ent)
611                         continue;
612                 if (ent->seen)
613                         commit->object.flags |= SHOWN;
614                 commit->util = NULL;
615         }
616
617         free_patch_ids(&ids);
618 }
619
620 /* How many extra uninteresting commits we want to see.. */
621 #define SLOP 5
622
623 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
624 {
625         /*
626          * No source list at all? We're definitely done..
627          */
628         if (!src)
629                 return 0;
630
631         /*
632          * Does the destination list contain entries with a date
633          * before the source list? Definitely _not_ done.
634          */
635         if (date < src->item->date)
636                 return SLOP;
637
638         /*
639          * Does the source list still have interesting commits in
640          * it? Definitely not done..
641          */
642         if (!everybody_uninteresting(src))
643                 return SLOP;
644
645         /* Ok, we're closing in.. */
646         return slop-1;
647 }
648
649 static int limit_list(struct rev_info *revs)
650 {
651         int slop = SLOP;
652         unsigned long date = ~0ul;
653         struct commit_list *list = revs->commits;
654         struct commit_list *newlist = NULL;
655         struct commit_list **p = &newlist;
656
657         while (list) {
658                 struct commit_list *entry = list;
659                 struct commit *commit = list->item;
660                 struct object *obj = &commit->object;
661                 show_early_output_fn_t show;
662
663                 list = list->next;
664                 free(entry);
665
666                 if (revs->max_age != -1 && (commit->date < revs->max_age))
667                         obj->flags |= UNINTERESTING;
668                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
669                         return -1;
670                 if (obj->flags & UNINTERESTING) {
671                         mark_parents_uninteresting(commit);
672                         if (revs->show_all)
673                                 p = &commit_list_insert(commit, p)->next;
674                         slop = still_interesting(list, date, slop);
675                         if (slop)
676                                 continue;
677                         /* If showing all, add the whole pending list to the end */
678                         if (revs->show_all)
679                                 *p = list;
680                         break;
681                 }
682                 if (revs->min_age != -1 && (commit->date > revs->min_age))
683                         continue;
684                 date = commit->date;
685                 p = &commit_list_insert(commit, p)->next;
686
687                 show = show_early_output;
688                 if (!show)
689                         continue;
690
691                 show(revs, newlist);
692                 show_early_output = NULL;
693         }
694         if (revs->cherry_pick)
695                 cherry_pick_list(newlist, revs);
696
697         revs->commits = newlist;
698         return 0;
699 }
700
701 struct all_refs_cb {
702         int all_flags;
703         int warned_bad_reflog;
704         struct rev_info *all_revs;
705         const char *name_for_errormsg;
706 };
707
708 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
709 {
710         struct all_refs_cb *cb = cb_data;
711         struct object *object = get_reference(cb->all_revs, path, sha1,
712                                               cb->all_flags);
713         add_pending_object(cb->all_revs, object, path);
714         return 0;
715 }
716
717 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
718         unsigned flags)
719 {
720         cb->all_revs = revs;
721         cb->all_flags = flags;
722 }
723
724 static void handle_refs(struct rev_info *revs, unsigned flags,
725                 int (*for_each)(each_ref_fn, void *))
726 {
727         struct all_refs_cb cb;
728         init_all_refs_cb(&cb, revs, flags);
729         for_each(handle_one_ref, &cb);
730 }
731
732 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
733 {
734         struct all_refs_cb *cb = cb_data;
735         if (!is_null_sha1(sha1)) {
736                 struct object *o = parse_object(sha1);
737                 if (o) {
738                         o->flags |= cb->all_flags;
739                         add_pending_object(cb->all_revs, o, "");
740                 }
741                 else if (!cb->warned_bad_reflog) {
742                         warning("reflog of '%s' references pruned commits",
743                                 cb->name_for_errormsg);
744                         cb->warned_bad_reflog = 1;
745                 }
746         }
747 }
748
749 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
750                 const char *email, unsigned long timestamp, int tz,
751                 const char *message, void *cb_data)
752 {
753         handle_one_reflog_commit(osha1, cb_data);
754         handle_one_reflog_commit(nsha1, cb_data);
755         return 0;
756 }
757
758 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
759 {
760         struct all_refs_cb *cb = cb_data;
761         cb->warned_bad_reflog = 0;
762         cb->name_for_errormsg = path;
763         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
764         return 0;
765 }
766
767 static void handle_reflog(struct rev_info *revs, unsigned flags)
768 {
769         struct all_refs_cb cb;
770         cb.all_revs = revs;
771         cb.all_flags = flags;
772         for_each_reflog(handle_one_reflog, &cb);
773 }
774
775 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
776 {
777         unsigned char sha1[20];
778         struct object *it;
779         struct commit *commit;
780         struct commit_list *parents;
781
782         if (*arg == '^') {
783                 flags ^= UNINTERESTING;
784                 arg++;
785         }
786         if (get_sha1(arg, sha1))
787                 return 0;
788         while (1) {
789                 it = get_reference(revs, arg, sha1, 0);
790                 if (it->type != OBJ_TAG)
791                         break;
792                 if (!((struct tag*)it)->tagged)
793                         return 0;
794                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
795         }
796         if (it->type != OBJ_COMMIT)
797                 return 0;
798         commit = (struct commit *)it;
799         for (parents = commit->parents; parents; parents = parents->next) {
800                 it = &parents->item->object;
801                 it->flags |= flags;
802                 add_pending_object(revs, it, arg);
803         }
804         return 1;
805 }
806
807 void init_revisions(struct rev_info *revs, const char *prefix)
808 {
809         memset(revs, 0, sizeof(*revs));
810
811         revs->abbrev = DEFAULT_ABBREV;
812         revs->ignore_merges = 1;
813         revs->simplify_history = 1;
814         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
815         DIFF_OPT_SET(&revs->pruning, QUICK);
816         revs->pruning.add_remove = file_add_remove;
817         revs->pruning.change = file_change;
818         revs->lifo = 1;
819         revs->dense = 1;
820         revs->prefix = prefix;
821         revs->max_age = -1;
822         revs->min_age = -1;
823         revs->skip_count = -1;
824         revs->max_count = -1;
825
826         revs->commit_format = CMIT_FMT_DEFAULT;
827
828         revs->grep_filter.status_only = 1;
829         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
830         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
831         revs->grep_filter.regflags = REG_NEWLINE;
832
833         diff_setup(&revs->diffopt);
834         if (prefix && !revs->diffopt.prefix) {
835                 revs->diffopt.prefix = prefix;
836                 revs->diffopt.prefix_length = strlen(prefix);
837         }
838 }
839
840 static void add_pending_commit_list(struct rev_info *revs,
841                                     struct commit_list *commit_list,
842                                     unsigned int flags)
843 {
844         while (commit_list) {
845                 struct object *object = &commit_list->item->object;
846                 object->flags |= flags;
847                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
848                 commit_list = commit_list->next;
849         }
850 }
851
852 static void prepare_show_merge(struct rev_info *revs)
853 {
854         struct commit_list *bases;
855         struct commit *head, *other;
856         unsigned char sha1[20];
857         const char **prune = NULL;
858         int i, prune_num = 1; /* counting terminating NULL */
859
860         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
861                 die("--merge without HEAD?");
862         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
863                 die("--merge without MERGE_HEAD?");
864         add_pending_object(revs, &head->object, "HEAD");
865         add_pending_object(revs, &other->object, "MERGE_HEAD");
866         bases = get_merge_bases(head, other, 1);
867         add_pending_commit_list(revs, bases, UNINTERESTING);
868         free_commit_list(bases);
869         head->object.flags |= SYMMETRIC_LEFT;
870
871         if (!active_nr)
872                 read_cache();
873         for (i = 0; i < active_nr; i++) {
874                 struct cache_entry *ce = active_cache[i];
875                 if (!ce_stage(ce))
876                         continue;
877                 if (ce_path_match(ce, revs->prune_data)) {
878                         prune_num++;
879                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
880                         prune[prune_num-2] = ce->name;
881                         prune[prune_num-1] = NULL;
882                 }
883                 while ((i+1 < active_nr) &&
884                        ce_same_name(ce, active_cache[i+1]))
885                         i++;
886         }
887         revs->prune_data = prune;
888         revs->limited = 1;
889 }
890
891 int handle_revision_arg(const char *arg, struct rev_info *revs,
892                         int flags,
893                         int cant_be_filename)
894 {
895         unsigned mode;
896         char *dotdot;
897         struct object *object;
898         unsigned char sha1[20];
899         int local_flags;
900
901         dotdot = strstr(arg, "..");
902         if (dotdot) {
903                 unsigned char from_sha1[20];
904                 const char *next = dotdot + 2;
905                 const char *this = arg;
906                 int symmetric = *next == '.';
907                 unsigned int flags_exclude = flags ^ UNINTERESTING;
908
909                 *dotdot = 0;
910                 next += symmetric;
911
912                 if (!*next)
913                         next = "HEAD";
914                 if (dotdot == arg)
915                         this = "HEAD";
916                 if (!get_sha1(this, from_sha1) &&
917                     !get_sha1(next, sha1)) {
918                         struct commit *a, *b;
919                         struct commit_list *exclude;
920
921                         a = lookup_commit_reference(from_sha1);
922                         b = lookup_commit_reference(sha1);
923                         if (!a || !b) {
924                                 die(symmetric ?
925                                     "Invalid symmetric difference expression %s...%s" :
926                                     "Invalid revision range %s..%s",
927                                     arg, next);
928                         }
929
930                         if (!cant_be_filename) {
931                                 *dotdot = '.';
932                                 verify_non_filename(revs->prefix, arg);
933                         }
934
935                         if (symmetric) {
936                                 exclude = get_merge_bases(a, b, 1);
937                                 add_pending_commit_list(revs, exclude,
938                                                         flags_exclude);
939                                 free_commit_list(exclude);
940                                 a->object.flags |= flags | SYMMETRIC_LEFT;
941                         } else
942                                 a->object.flags |= flags_exclude;
943                         b->object.flags |= flags;
944                         add_pending_object(revs, &a->object, this);
945                         add_pending_object(revs, &b->object, next);
946                         return 0;
947                 }
948                 *dotdot = '.';
949         }
950         dotdot = strstr(arg, "^@");
951         if (dotdot && !dotdot[2]) {
952                 *dotdot = 0;
953                 if (add_parents_only(revs, arg, flags))
954                         return 0;
955                 *dotdot = '^';
956         }
957         dotdot = strstr(arg, "^!");
958         if (dotdot && !dotdot[2]) {
959                 *dotdot = 0;
960                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
961                         *dotdot = '^';
962         }
963
964         local_flags = 0;
965         if (*arg == '^') {
966                 local_flags = UNINTERESTING;
967                 arg++;
968         }
969         if (get_sha1_with_mode(arg, sha1, &mode))
970                 return -1;
971         if (!cant_be_filename)
972                 verify_non_filename(revs->prefix, arg);
973         object = get_reference(revs, arg, sha1, flags ^ local_flags);
974         add_pending_object_with_mode(revs, object, arg, mode);
975         return 0;
976 }
977
978 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
979 {
980         const char **prune = *prune_data;
981         int prune_nr;
982         int prune_alloc;
983
984         /* count existing ones */
985         if (!prune)
986                 prune_nr = 0;
987         else
988                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
989                         ;
990         prune_alloc = prune_nr; /* not really, but we do not know */
991
992         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
993                 int len = sb->len;
994                 if (len && sb->buf[len - 1] == '\n')
995                         sb->buf[--len] = '\0';
996                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
997                 prune[prune_nr++] = xstrdup(sb->buf);
998         }
999         if (prune) {
1000                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1001                 prune[prune_nr] = NULL;
1002         }
1003         *prune_data = prune;
1004 }
1005
1006 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1007 {
1008         struct strbuf sb;
1009         int seen_dashdash = 0;
1010
1011         strbuf_init(&sb, 1000);
1012         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1013                 int len = sb.len;
1014                 if (len && sb.buf[len - 1] == '\n')
1015                         sb.buf[--len] = '\0';
1016                 if (!len)
1017                         break;
1018                 if (sb.buf[0] == '-') {
1019                         if (len == 2 && sb.buf[1] == '-') {
1020                                 seen_dashdash = 1;
1021                                 break;
1022                         }
1023                         die("options not supported in --stdin mode");
1024                 }
1025                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1026                         die("bad revision '%s'", sb.buf);
1027         }
1028         if (seen_dashdash)
1029                 read_pathspec_from_stdin(revs, &sb, prune);
1030         strbuf_release(&sb);
1031 }
1032
1033 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1034 {
1035         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1036 }
1037
1038 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1039 {
1040         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1041 }
1042
1043 static void add_message_grep(struct rev_info *revs, const char *pattern)
1044 {
1045         add_grep(revs, pattern, GREP_PATTERN_BODY);
1046 }
1047
1048 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1049                                int *unkc, const char **unkv)
1050 {
1051         const char *arg = argv[0];
1052
1053         /* pseudo revision arguments */
1054         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1055             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1056             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1057             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1058             !strcmp(arg, "--bisect"))
1059         {
1060                 unkv[(*unkc)++] = arg;
1061                 return 1;
1062         }
1063
1064         if (!prefixcmp(arg, "--max-count=")) {
1065                 revs->max_count = atoi(arg + 12);
1066         } else if (!prefixcmp(arg, "--skip=")) {
1067                 revs->skip_count = atoi(arg + 7);
1068         } else if ((*arg == '-') && isdigit(arg[1])) {
1069         /* accept -<digit>, like traditional "head" */
1070                 revs->max_count = atoi(arg + 1);
1071         } else if (!strcmp(arg, "-n")) {
1072                 if (argc <= 1)
1073                         return error("-n requires an argument");
1074                 revs->max_count = atoi(argv[1]);
1075                 return 2;
1076         } else if (!prefixcmp(arg, "-n")) {
1077                 revs->max_count = atoi(arg + 2);
1078         } else if (!prefixcmp(arg, "--max-age=")) {
1079                 revs->max_age = atoi(arg + 10);
1080         } else if (!prefixcmp(arg, "--since=")) {
1081                 revs->max_age = approxidate(arg + 8);
1082         } else if (!prefixcmp(arg, "--after=")) {
1083                 revs->max_age = approxidate(arg + 8);
1084         } else if (!prefixcmp(arg, "--min-age=")) {
1085                 revs->min_age = atoi(arg + 10);
1086         } else if (!prefixcmp(arg, "--before=")) {
1087                 revs->min_age = approxidate(arg + 9);
1088         } else if (!prefixcmp(arg, "--until=")) {
1089                 revs->min_age = approxidate(arg + 8);
1090         } else if (!strcmp(arg, "--first-parent")) {
1091                 revs->first_parent_only = 1;
1092         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1093                 init_reflog_walk(&revs->reflog_info);
1094         } else if (!strcmp(arg, "--default")) {
1095                 if (argc <= 1)
1096                         return error("bad --default argument");
1097                 revs->def = argv[1];
1098                 return 2;
1099         } else if (!strcmp(arg, "--merge")) {
1100                 revs->show_merge = 1;
1101         } else if (!strcmp(arg, "--topo-order")) {
1102                 revs->lifo = 1;
1103                 revs->topo_order = 1;
1104         } else if (!strcmp(arg, "--simplify-merges")) {
1105                 revs->simplify_merges = 1;
1106                 revs->rewrite_parents = 1;
1107                 revs->simplify_history = 0;
1108                 revs->limited = 1;
1109         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1110                 revs->simplify_merges = 1;
1111                 revs->rewrite_parents = 1;
1112                 revs->simplify_history = 0;
1113                 revs->simplify_by_decoration = 1;
1114                 revs->limited = 1;
1115                 revs->prune = 1;
1116                 load_ref_decorations(DECORATE_SHORT_REFS);
1117         } else if (!strcmp(arg, "--date-order")) {
1118                 revs->lifo = 0;
1119                 revs->topo_order = 1;
1120         } else if (!prefixcmp(arg, "--early-output")) {
1121                 int count = 100;
1122                 switch (arg[14]) {
1123                 case '=':
1124                         count = atoi(arg+15);
1125                         /* Fallthrough */
1126                 case 0:
1127                         revs->topo_order = 1;
1128                        revs->early_output = count;
1129                 }
1130         } else if (!strcmp(arg, "--parents")) {
1131                 revs->rewrite_parents = 1;
1132                 revs->print_parents = 1;
1133         } else if (!strcmp(arg, "--dense")) {
1134                 revs->dense = 1;
1135         } else if (!strcmp(arg, "--sparse")) {
1136                 revs->dense = 0;
1137         } else if (!strcmp(arg, "--show-all")) {
1138                 revs->show_all = 1;
1139         } else if (!strcmp(arg, "--remove-empty")) {
1140                 revs->remove_empty_trees = 1;
1141         } else if (!strcmp(arg, "--merges")) {
1142                 revs->merges_only = 1;
1143         } else if (!strcmp(arg, "--no-merges")) {
1144                 revs->no_merges = 1;
1145         } else if (!strcmp(arg, "--boundary")) {
1146                 revs->boundary = 1;
1147         } else if (!strcmp(arg, "--left-right")) {
1148                 revs->left_right = 1;
1149         } else if (!strcmp(arg, "--cherry-pick")) {
1150                 revs->cherry_pick = 1;
1151                 revs->limited = 1;
1152         } else if (!strcmp(arg, "--objects")) {
1153                 revs->tag_objects = 1;
1154                 revs->tree_objects = 1;
1155                 revs->blob_objects = 1;
1156         } else if (!strcmp(arg, "--objects-edge")) {
1157                 revs->tag_objects = 1;
1158                 revs->tree_objects = 1;
1159                 revs->blob_objects = 1;
1160                 revs->edge_hint = 1;
1161         } else if (!strcmp(arg, "--unpacked")) {
1162                 revs->unpacked = 1;
1163         } else if (!prefixcmp(arg, "--unpacked=")) {
1164                 die("--unpacked=<packfile> no longer supported.");
1165         } else if (!strcmp(arg, "-r")) {
1166                 revs->diff = 1;
1167                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1168         } else if (!strcmp(arg, "-t")) {
1169                 revs->diff = 1;
1170                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1171                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1172         } else if (!strcmp(arg, "-m")) {
1173                 revs->ignore_merges = 0;
1174         } else if (!strcmp(arg, "-c")) {
1175                 revs->diff = 1;
1176                 revs->dense_combined_merges = 0;
1177                 revs->combine_merges = 1;
1178         } else if (!strcmp(arg, "--cc")) {
1179                 revs->diff = 1;
1180                 revs->dense_combined_merges = 1;
1181                 revs->combine_merges = 1;
1182         } else if (!strcmp(arg, "-v")) {
1183                 revs->verbose_header = 1;
1184         } else if (!strcmp(arg, "--pretty")) {
1185                 revs->verbose_header = 1;
1186                 revs->pretty_given = 1;
1187                 get_commit_format(arg+8, revs);
1188         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1189                 revs->verbose_header = 1;
1190                 revs->pretty_given = 1;
1191                 get_commit_format(arg+9, revs);
1192         } else if (!strcmp(arg, "--show-notes")) {
1193                 revs->show_notes = 1;
1194                 revs->show_notes_given = 1;
1195         } else if (!prefixcmp(arg, "--show-notes=")) {
1196                 struct strbuf buf = STRBUF_INIT;
1197                 revs->show_notes = 1;
1198                 revs->show_notes_given = 1;
1199                 if (!revs->notes_opt.extra_notes_refs)
1200                         revs->notes_opt.extra_notes_refs = xcalloc(1, sizeof(struct string_list));
1201                 if (!prefixcmp(arg+13, "refs/"))
1202                         /* happy */;
1203                 else if (!prefixcmp(arg+13, "notes/"))
1204                         strbuf_addstr(&buf, "refs/");
1205                 else
1206                         strbuf_addstr(&buf, "refs/notes/");
1207                 strbuf_addstr(&buf, arg+13);
1208                 string_list_append(strbuf_detach(&buf, NULL),
1209                                    revs->notes_opt.extra_notes_refs);
1210         } else if (!strcmp(arg, "--no-notes")) {
1211                 revs->show_notes = 0;
1212                 revs->show_notes_given = 1;
1213         } else if (!strcmp(arg, "--standard-notes")) {
1214                 revs->show_notes_given = 1;
1215                 revs->notes_opt.suppress_default_notes = 0;
1216         } else if (!strcmp(arg, "--no-standard-notes")) {
1217                 revs->notes_opt.suppress_default_notes = 1;
1218         } else if (!strcmp(arg, "--oneline")) {
1219                 revs->verbose_header = 1;
1220                 get_commit_format("oneline", revs);
1221                 revs->pretty_given = 1;
1222                 revs->abbrev_commit = 1;
1223         } else if (!strcmp(arg, "--graph")) {
1224                 revs->topo_order = 1;
1225                 revs->rewrite_parents = 1;
1226                 revs->graph = graph_init(revs);
1227         } else if (!strcmp(arg, "--root")) {
1228                 revs->show_root_diff = 1;
1229         } else if (!strcmp(arg, "--no-commit-id")) {
1230                 revs->no_commit_id = 1;
1231         } else if (!strcmp(arg, "--always")) {
1232                 revs->always_show_header = 1;
1233         } else if (!strcmp(arg, "--no-abbrev")) {
1234                 revs->abbrev = 0;
1235         } else if (!strcmp(arg, "--abbrev")) {
1236                 revs->abbrev = DEFAULT_ABBREV;
1237         } else if (!prefixcmp(arg, "--abbrev=")) {
1238                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1239                 if (revs->abbrev < MINIMUM_ABBREV)
1240                         revs->abbrev = MINIMUM_ABBREV;
1241                 else if (revs->abbrev > 40)
1242                         revs->abbrev = 40;
1243         } else if (!strcmp(arg, "--abbrev-commit")) {
1244                 revs->abbrev_commit = 1;
1245         } else if (!strcmp(arg, "--full-diff")) {
1246                 revs->diff = 1;
1247                 revs->full_diff = 1;
1248         } else if (!strcmp(arg, "--full-history")) {
1249                 revs->simplify_history = 0;
1250         } else if (!strcmp(arg, "--relative-date")) {
1251                 revs->date_mode = DATE_RELATIVE;
1252                 revs->date_mode_explicit = 1;
1253         } else if (!strncmp(arg, "--date=", 7)) {
1254                 revs->date_mode = parse_date_format(arg + 7);
1255                 revs->date_mode_explicit = 1;
1256         } else if (!strcmp(arg, "--log-size")) {
1257                 revs->show_log_size = 1;
1258         }
1259         /*
1260          * Grepping the commit log
1261          */
1262         else if (!prefixcmp(arg, "--author=")) {
1263                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1264         } else if (!prefixcmp(arg, "--committer=")) {
1265                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1266         } else if (!prefixcmp(arg, "--grep=")) {
1267                 add_message_grep(revs, arg+7);
1268         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1269                 revs->grep_filter.regflags |= REG_EXTENDED;
1270         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1271                 revs->grep_filter.regflags |= REG_ICASE;
1272         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1273                 revs->grep_filter.fixed = 1;
1274         } else if (!strcmp(arg, "--all-match")) {
1275                 revs->grep_filter.all_match = 1;
1276         } else if (!prefixcmp(arg, "--encoding=")) {
1277                 arg += 11;
1278                 if (strcmp(arg, "none"))
1279                         git_log_output_encoding = xstrdup(arg);
1280                 else
1281                         git_log_output_encoding = "";
1282         } else if (!strcmp(arg, "--reverse")) {
1283                 revs->reverse ^= 1;
1284         } else if (!strcmp(arg, "--children")) {
1285                 revs->children.name = "children";
1286                 revs->limited = 1;
1287         } else {
1288                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1289                 if (!opts)
1290                         unkv[(*unkc)++] = arg;
1291                 return opts;
1292         }
1293
1294         return 1;
1295 }
1296
1297 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1298                         const struct option *options,
1299                         const char * const usagestr[])
1300 {
1301         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1302                                     &ctx->cpidx, ctx->out);
1303         if (n <= 0) {
1304                 error("unknown option `%s'", ctx->argv[0]);
1305                 usage_with_options(usagestr, options);
1306         }
1307         ctx->argv += n;
1308         ctx->argc -= n;
1309 }
1310
1311 static int for_each_bad_bisect_ref(each_ref_fn fn, void *cb_data)
1312 {
1313         return for_each_ref_in("refs/bisect/bad", fn, cb_data);
1314 }
1315
1316 static int for_each_good_bisect_ref(each_ref_fn fn, void *cb_data)
1317 {
1318         return for_each_ref_in("refs/bisect/good", fn, cb_data);
1319 }
1320
1321 static void append_prune_data(const char ***prune_data, const char **av)
1322 {
1323         const char **prune = *prune_data;
1324         int prune_nr;
1325         int prune_alloc;
1326
1327         if (!prune) {
1328                 *prune_data = av;
1329                 return;
1330         }
1331
1332         /* count existing ones */
1333         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1334                 ;
1335         prune_alloc = prune_nr; /* not really, but we do not know */
1336
1337         while (*av) {
1338                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1339                 prune[prune_nr++] = *av;
1340                 av++;
1341         }
1342         if (prune) {
1343                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1344                 prune[prune_nr] = NULL;
1345         }
1346         *prune_data = prune;
1347 }
1348
1349 /*
1350  * Parse revision information, filling in the "rev_info" structure,
1351  * and removing the used arguments from the argument list.
1352  *
1353  * Returns the number of arguments left that weren't recognized
1354  * (which are also moved to the head of the argument list)
1355  */
1356 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1357 {
1358         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1359         const char **prune_data = NULL;
1360
1361         /* First, search for "--" */
1362         seen_dashdash = 0;
1363         for (i = 1; i < argc; i++) {
1364                 const char *arg = argv[i];
1365                 if (strcmp(arg, "--"))
1366                         continue;
1367                 argv[i] = NULL;
1368                 argc = i;
1369                 if (argv[i + 1])
1370                         prune_data = argv + i + 1;
1371                 seen_dashdash = 1;
1372                 break;
1373         }
1374
1375         /* Second, deal with arguments and options */
1376         flags = 0;
1377         read_from_stdin = 0;
1378         for (left = i = 1; i < argc; i++) {
1379                 const char *arg = argv[i];
1380                 if (*arg == '-') {
1381                         int opts;
1382
1383                         if (!strcmp(arg, "--all")) {
1384                                 handle_refs(revs, flags, for_each_ref);
1385                                 handle_refs(revs, flags, head_ref);
1386                                 continue;
1387                         }
1388                         if (!strcmp(arg, "--branches")) {
1389                                 handle_refs(revs, flags, for_each_branch_ref);
1390                                 continue;
1391                         }
1392                         if (!strcmp(arg, "--bisect")) {
1393                                 handle_refs(revs, flags, for_each_bad_bisect_ref);
1394                                 handle_refs(revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1395                                 revs->bisect = 1;
1396                                 continue;
1397                         }
1398                         if (!strcmp(arg, "--tags")) {
1399                                 handle_refs(revs, flags, for_each_tag_ref);
1400                                 continue;
1401                         }
1402                         if (!strcmp(arg, "--remotes")) {
1403                                 handle_refs(revs, flags, for_each_remote_ref);
1404                                 continue;
1405                         }
1406                         if (!prefixcmp(arg, "--glob=")) {
1407                                 struct all_refs_cb cb;
1408                                 init_all_refs_cb(&cb, revs, flags);
1409                                 for_each_glob_ref(handle_one_ref, arg + 7, &cb);
1410                                 continue;
1411                         }
1412                         if (!prefixcmp(arg, "--branches=")) {
1413                                 struct all_refs_cb cb;
1414                                 init_all_refs_cb(&cb, revs, flags);
1415                                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1416                                 continue;
1417                         }
1418                         if (!prefixcmp(arg, "--tags=")) {
1419                                 struct all_refs_cb cb;
1420                                 init_all_refs_cb(&cb, revs, flags);
1421                                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1422                                 continue;
1423                         }
1424                         if (!prefixcmp(arg, "--remotes=")) {
1425                                 struct all_refs_cb cb;
1426                                 init_all_refs_cb(&cb, revs, flags);
1427                                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1428                                 continue;
1429                         }
1430                         if (!strcmp(arg, "--reflog")) {
1431                                 handle_reflog(revs, flags);
1432                                 continue;
1433                         }
1434                         if (!strcmp(arg, "--not")) {
1435                                 flags ^= UNINTERESTING;
1436                                 continue;
1437                         }
1438                         if (!strcmp(arg, "--no-walk")) {
1439                                 revs->no_walk = 1;
1440                                 continue;
1441                         }
1442                         if (!strcmp(arg, "--do-walk")) {
1443                                 revs->no_walk = 0;
1444                                 continue;
1445                         }
1446                         if (!strcmp(arg, "--stdin")) {
1447                                 if (revs->disable_stdin) {
1448                                         argv[left++] = arg;
1449                                         continue;
1450                                 }
1451                                 if (read_from_stdin++)
1452                                         die("--stdin given twice?");
1453                                 read_revisions_from_stdin(revs, &prune_data);
1454                                 continue;
1455                         }
1456
1457                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1458                         if (opts > 0) {
1459                                 i += opts - 1;
1460                                 continue;
1461                         }
1462                         if (opts < 0)
1463                                 exit(128);
1464                         continue;
1465                 }
1466
1467                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1468                         int j;
1469                         if (seen_dashdash || *arg == '^')
1470                                 die("bad revision '%s'", arg);
1471
1472                         /* If we didn't have a "--":
1473                          * (1) all filenames must exist;
1474                          * (2) all rev-args must not be interpretable
1475                          *     as a valid filename.
1476                          * but the latter we have checked in the main loop.
1477                          */
1478                         for (j = i; j < argc; j++)
1479                                 verify_filename(revs->prefix, argv[j]);
1480
1481                         append_prune_data(&prune_data, argv + i);
1482                         break;
1483                 }
1484                 else
1485                         got_rev_arg = 1;
1486         }
1487
1488         if (prune_data)
1489                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1490
1491         if (revs->def == NULL)
1492                 revs->def = opt ? opt->def : NULL;
1493         if (opt && opt->tweak)
1494                 opt->tweak(revs, opt);
1495         if (revs->show_merge)
1496                 prepare_show_merge(revs);
1497         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1498                 unsigned char sha1[20];
1499                 struct object *object;
1500                 unsigned mode;
1501                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1502                         die("bad default revision '%s'", revs->def);
1503                 object = get_reference(revs, revs->def, sha1, 0);
1504                 add_pending_object_with_mode(revs, object, revs->def, mode);
1505         }
1506
1507         /* Did the user ask for any diff output? Run the diff! */
1508         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1509                 revs->diff = 1;
1510
1511         /* Pickaxe, diff-filter and rename following need diffs */
1512         if (revs->diffopt.pickaxe ||
1513             revs->diffopt.filter ||
1514             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1515                 revs->diff = 1;
1516
1517         if (revs->topo_order)
1518                 revs->limited = 1;
1519
1520         if (revs->prune_data) {
1521                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1522                 /* Can't prune commits with rename following: the paths change.. */
1523                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1524                         revs->prune = 1;
1525                 if (!revs->full_diff)
1526                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1527         }
1528         if (revs->combine_merges)
1529                 revs->ignore_merges = 0;
1530         revs->diffopt.abbrev = revs->abbrev;
1531         if (diff_setup_done(&revs->diffopt) < 0)
1532                 die("diff_setup_done failed");
1533
1534         compile_grep_patterns(&revs->grep_filter);
1535
1536         if (revs->reverse && revs->reflog_info)
1537                 die("cannot combine --reverse with --walk-reflogs");
1538         if (revs->rewrite_parents && revs->children.name)
1539                 die("cannot combine --parents and --children");
1540
1541         /*
1542          * Limitations on the graph functionality
1543          */
1544         if (revs->reverse && revs->graph)
1545                 die("cannot combine --reverse with --graph");
1546
1547         if (revs->reflog_info && revs->graph)
1548                 die("cannot combine --walk-reflogs with --graph");
1549
1550         return left;
1551 }
1552
1553 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1554 {
1555         struct commit_list *l = xcalloc(1, sizeof(*l));
1556
1557         l->item = child;
1558         l->next = add_decoration(&revs->children, &parent->object, l);
1559 }
1560
1561 static int remove_duplicate_parents(struct commit *commit)
1562 {
1563         struct commit_list **pp, *p;
1564         int surviving_parents;
1565
1566         /* Examine existing parents while marking ones we have seen... */
1567         pp = &commit->parents;
1568         while ((p = *pp) != NULL) {
1569                 struct commit *parent = p->item;
1570                 if (parent->object.flags & TMP_MARK) {
1571                         *pp = p->next;
1572                         continue;
1573                 }
1574                 parent->object.flags |= TMP_MARK;
1575                 pp = &p->next;
1576         }
1577         /* count them while clearing the temporary mark */
1578         surviving_parents = 0;
1579         for (p = commit->parents; p; p = p->next) {
1580                 p->item->object.flags &= ~TMP_MARK;
1581                 surviving_parents++;
1582         }
1583         return surviving_parents;
1584 }
1585
1586 struct merge_simplify_state {
1587         struct commit *simplified;
1588 };
1589
1590 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1591 {
1592         struct merge_simplify_state *st;
1593
1594         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1595         if (!st) {
1596                 st = xcalloc(1, sizeof(*st));
1597                 add_decoration(&revs->merge_simplification, &commit->object, st);
1598         }
1599         return st;
1600 }
1601
1602 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1603 {
1604         struct commit_list *p;
1605         struct merge_simplify_state *st, *pst;
1606         int cnt;
1607
1608         st = locate_simplify_state(revs, commit);
1609
1610         /*
1611          * Have we handled this one?
1612          */
1613         if (st->simplified)
1614                 return tail;
1615
1616         /*
1617          * An UNINTERESTING commit simplifies to itself, so does a
1618          * root commit.  We do not rewrite parents of such commit
1619          * anyway.
1620          */
1621         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1622                 st->simplified = commit;
1623                 return tail;
1624         }
1625
1626         /*
1627          * Do we know what commit all of our parents should be rewritten to?
1628          * Otherwise we are not ready to rewrite this one yet.
1629          */
1630         for (cnt = 0, p = commit->parents; p; p = p->next) {
1631                 pst = locate_simplify_state(revs, p->item);
1632                 if (!pst->simplified) {
1633                         tail = &commit_list_insert(p->item, tail)->next;
1634                         cnt++;
1635                 }
1636         }
1637         if (cnt) {
1638                 tail = &commit_list_insert(commit, tail)->next;
1639                 return tail;
1640         }
1641
1642         /*
1643          * Rewrite our list of parents.
1644          */
1645         for (p = commit->parents; p; p = p->next) {
1646                 pst = locate_simplify_state(revs, p->item);
1647                 p->item = pst->simplified;
1648         }
1649         cnt = remove_duplicate_parents(commit);
1650
1651         /*
1652          * It is possible that we are a merge and one side branch
1653          * does not have any commit that touches the given paths;
1654          * in such a case, the immediate parents will be rewritten
1655          * to different commits.
1656          *
1657          *      o----X          X: the commit we are looking at;
1658          *     /    /           o: a commit that touches the paths;
1659          * ---o----'
1660          *
1661          * Further reduce the parents by removing redundant parents.
1662          */
1663         if (1 < cnt) {
1664                 struct commit_list *h = reduce_heads(commit->parents);
1665                 cnt = commit_list_count(h);
1666                 free_commit_list(commit->parents);
1667                 commit->parents = h;
1668         }
1669
1670         /*
1671          * A commit simplifies to itself if it is a root, if it is
1672          * UNINTERESTING, if it touches the given paths, or if it is a
1673          * merge and its parents simplifies to more than one commits
1674          * (the first two cases are already handled at the beginning of
1675          * this function).
1676          *
1677          * Otherwise, it simplifies to what its sole parent simplifies to.
1678          */
1679         if (!cnt ||
1680             (commit->object.flags & UNINTERESTING) ||
1681             !(commit->object.flags & TREESAME) ||
1682             (1 < cnt))
1683                 st->simplified = commit;
1684         else {
1685                 pst = locate_simplify_state(revs, commit->parents->item);
1686                 st->simplified = pst->simplified;
1687         }
1688         return tail;
1689 }
1690
1691 static void simplify_merges(struct rev_info *revs)
1692 {
1693         struct commit_list *list;
1694         struct commit_list *yet_to_do, **tail;
1695
1696         if (!revs->topo_order)
1697                 sort_in_topological_order(&revs->commits, revs->lifo);
1698         if (!revs->prune)
1699                 return;
1700
1701         /* feed the list reversed */
1702         yet_to_do = NULL;
1703         for (list = revs->commits; list; list = list->next)
1704                 commit_list_insert(list->item, &yet_to_do);
1705         while (yet_to_do) {
1706                 list = yet_to_do;
1707                 yet_to_do = NULL;
1708                 tail = &yet_to_do;
1709                 while (list) {
1710                         struct commit *commit = list->item;
1711                         struct commit_list *next = list->next;
1712                         free(list);
1713                         list = next;
1714                         tail = simplify_one(revs, commit, tail);
1715                 }
1716         }
1717
1718         /* clean up the result, removing the simplified ones */
1719         list = revs->commits;
1720         revs->commits = NULL;
1721         tail = &revs->commits;
1722         while (list) {
1723                 struct commit *commit = list->item;
1724                 struct commit_list *next = list->next;
1725                 struct merge_simplify_state *st;
1726                 free(list);
1727                 list = next;
1728                 st = locate_simplify_state(revs, commit);
1729                 if (st->simplified == commit)
1730                         tail = &commit_list_insert(commit, tail)->next;
1731         }
1732 }
1733
1734 static void set_children(struct rev_info *revs)
1735 {
1736         struct commit_list *l;
1737         for (l = revs->commits; l; l = l->next) {
1738                 struct commit *commit = l->item;
1739                 struct commit_list *p;
1740
1741                 for (p = commit->parents; p; p = p->next)
1742                         add_child(revs, p->item, commit);
1743         }
1744 }
1745
1746 int prepare_revision_walk(struct rev_info *revs)
1747 {
1748         int nr = revs->pending.nr;
1749         struct object_array_entry *e, *list;
1750
1751         e = list = revs->pending.objects;
1752         revs->pending.nr = 0;
1753         revs->pending.alloc = 0;
1754         revs->pending.objects = NULL;
1755         while (--nr >= 0) {
1756                 struct commit *commit = handle_commit(revs, e->item, e->name);
1757                 if (commit) {
1758                         if (!(commit->object.flags & SEEN)) {
1759                                 commit->object.flags |= SEEN;
1760                                 insert_by_date(commit, &revs->commits);
1761                         }
1762                 }
1763                 e++;
1764         }
1765         free(list);
1766
1767         if (revs->no_walk)
1768                 return 0;
1769         if (revs->limited)
1770                 if (limit_list(revs) < 0)
1771                         return -1;
1772         if (revs->topo_order)
1773                 sort_in_topological_order(&revs->commits, revs->lifo);
1774         if (revs->simplify_merges)
1775                 simplify_merges(revs);
1776         if (revs->children.name)
1777                 set_children(revs);
1778         return 0;
1779 }
1780
1781 enum rewrite_result {
1782         rewrite_one_ok,
1783         rewrite_one_noparents,
1784         rewrite_one_error,
1785 };
1786
1787 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1788 {
1789         struct commit_list *cache = NULL;
1790
1791         for (;;) {
1792                 struct commit *p = *pp;
1793                 if (!revs->limited)
1794                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1795                                 return rewrite_one_error;
1796                 if (p->parents && p->parents->next)
1797                         return rewrite_one_ok;
1798                 if (p->object.flags & UNINTERESTING)
1799                         return rewrite_one_ok;
1800                 if (!(p->object.flags & TREESAME))
1801                         return rewrite_one_ok;
1802                 if (!p->parents)
1803                         return rewrite_one_noparents;
1804                 *pp = p->parents->item;
1805         }
1806 }
1807
1808 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1809 {
1810         struct commit_list **pp = &commit->parents;
1811         while (*pp) {
1812                 struct commit_list *parent = *pp;
1813                 switch (rewrite_one(revs, &parent->item)) {
1814                 case rewrite_one_ok:
1815                         break;
1816                 case rewrite_one_noparents:
1817                         *pp = parent->next;
1818                         continue;
1819                 case rewrite_one_error:
1820                         return -1;
1821                 }
1822                 pp = &parent->next;
1823         }
1824         remove_duplicate_parents(commit);
1825         return 0;
1826 }
1827
1828 static int commit_match(struct commit *commit, struct rev_info *opt)
1829 {
1830         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
1831                 return 1;
1832         return grep_buffer(&opt->grep_filter,
1833                            NULL, /* we say nothing, not even filename */
1834                            commit->buffer, strlen(commit->buffer));
1835 }
1836
1837 static inline int want_ancestry(struct rev_info *revs)
1838 {
1839         return (revs->rewrite_parents || revs->children.name);
1840 }
1841
1842 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1843 {
1844         if (commit->object.flags & SHOWN)
1845                 return commit_ignore;
1846         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1847                 return commit_ignore;
1848         if (revs->show_all)
1849                 return commit_show;
1850         if (commit->object.flags & UNINTERESTING)
1851                 return commit_ignore;
1852         if (revs->min_age != -1 && (commit->date > revs->min_age))
1853                 return commit_ignore;
1854         if (revs->no_merges && commit->parents && commit->parents->next)
1855                 return commit_ignore;
1856         if (revs->merges_only && !(commit->parents && commit->parents->next))
1857                 return commit_ignore;
1858         if (!commit_match(commit, revs))
1859                 return commit_ignore;
1860         if (revs->prune && revs->dense) {
1861                 /* Commit without changes? */
1862                 if (commit->object.flags & TREESAME) {
1863                         /* drop merges unless we want parenthood */
1864                         if (!want_ancestry(revs))
1865                                 return commit_ignore;
1866                         /* non-merge - always ignore it */
1867                         if (!commit->parents || !commit->parents->next)
1868                                 return commit_ignore;
1869                 }
1870         }
1871         return commit_show;
1872 }
1873
1874 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1875 {
1876         enum commit_action action = get_commit_action(revs, commit);
1877
1878         if (action == commit_show &&
1879             !revs->show_all &&
1880             revs->prune && revs->dense && want_ancestry(revs)) {
1881                 if (rewrite_parents(revs, commit) < 0)
1882                         return commit_error;
1883         }
1884         return action;
1885 }
1886
1887 static struct commit *get_revision_1(struct rev_info *revs)
1888 {
1889         if (!revs->commits)
1890                 return NULL;
1891
1892         do {
1893                 struct commit_list *entry = revs->commits;
1894                 struct commit *commit = entry->item;
1895
1896                 revs->commits = entry->next;
1897                 free(entry);
1898
1899                 if (revs->reflog_info)
1900                         fake_reflog_parent(revs->reflog_info, commit);
1901
1902                 /*
1903                  * If we haven't done the list limiting, we need to look at
1904                  * the parents here. We also need to do the date-based limiting
1905                  * that we'd otherwise have done in limit_list().
1906                  */
1907                 if (!revs->limited) {
1908                         if (revs->max_age != -1 &&
1909                             (commit->date < revs->max_age))
1910                                 continue;
1911                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1912                                 die("Failed to traverse parents of commit %s",
1913                                     sha1_to_hex(commit->object.sha1));
1914                 }
1915
1916                 switch (simplify_commit(revs, commit)) {
1917                 case commit_ignore:
1918                         continue;
1919                 case commit_error:
1920                         die("Failed to simplify parents of commit %s",
1921                             sha1_to_hex(commit->object.sha1));
1922                 default:
1923                         return commit;
1924                 }
1925         } while (revs->commits);
1926         return NULL;
1927 }
1928
1929 static void gc_boundary(struct object_array *array)
1930 {
1931         unsigned nr = array->nr;
1932         unsigned alloc = array->alloc;
1933         struct object_array_entry *objects = array->objects;
1934
1935         if (alloc <= nr) {
1936                 unsigned i, j;
1937                 for (i = j = 0; i < nr; i++) {
1938                         if (objects[i].item->flags & SHOWN)
1939                                 continue;
1940                         if (i != j)
1941                                 objects[j] = objects[i];
1942                         j++;
1943                 }
1944                 for (i = j; i < nr; i++)
1945                         objects[i].item = NULL;
1946                 array->nr = j;
1947         }
1948 }
1949
1950 static void create_boundary_commit_list(struct rev_info *revs)
1951 {
1952         unsigned i;
1953         struct commit *c;
1954         struct object_array *array = &revs->boundary_commits;
1955         struct object_array_entry *objects = array->objects;
1956
1957         /*
1958          * If revs->commits is non-NULL at this point, an error occurred in
1959          * get_revision_1().  Ignore the error and continue printing the
1960          * boundary commits anyway.  (This is what the code has always
1961          * done.)
1962          */
1963         if (revs->commits) {
1964                 free_commit_list(revs->commits);
1965                 revs->commits = NULL;
1966         }
1967
1968         /*
1969          * Put all of the actual boundary commits from revs->boundary_commits
1970          * into revs->commits
1971          */
1972         for (i = 0; i < array->nr; i++) {
1973                 c = (struct commit *)(objects[i].item);
1974                 if (!c)
1975                         continue;
1976                 if (!(c->object.flags & CHILD_SHOWN))
1977                         continue;
1978                 if (c->object.flags & (SHOWN | BOUNDARY))
1979                         continue;
1980                 c->object.flags |= BOUNDARY;
1981                 commit_list_insert(c, &revs->commits);
1982         }
1983
1984         /*
1985          * If revs->topo_order is set, sort the boundary commits
1986          * in topological order
1987          */
1988         sort_in_topological_order(&revs->commits, revs->lifo);
1989 }
1990
1991 static struct commit *get_revision_internal(struct rev_info *revs)
1992 {
1993         struct commit *c = NULL;
1994         struct commit_list *l;
1995
1996         if (revs->boundary == 2) {
1997                 /*
1998                  * All of the normal commits have already been returned,
1999                  * and we are now returning boundary commits.
2000                  * create_boundary_commit_list() has populated
2001                  * revs->commits with the remaining commits to return.
2002                  */
2003                 c = pop_commit(&revs->commits);
2004                 if (c)
2005                         c->object.flags |= SHOWN;
2006                 return c;
2007         }
2008
2009         /*
2010          * Now pick up what they want to give us
2011          */
2012         c = get_revision_1(revs);
2013         if (c) {
2014                 while (0 < revs->skip_count) {
2015                         revs->skip_count--;
2016                         c = get_revision_1(revs);
2017                         if (!c)
2018                                 break;
2019                 }
2020         }
2021
2022         /*
2023          * Check the max_count.
2024          */
2025         switch (revs->max_count) {
2026         case -1:
2027                 break;
2028         case 0:
2029                 c = NULL;
2030                 break;
2031         default:
2032                 revs->max_count--;
2033         }
2034
2035         if (c)
2036                 c->object.flags |= SHOWN;
2037
2038         if (!revs->boundary) {
2039                 return c;
2040         }
2041
2042         if (!c) {
2043                 /*
2044                  * get_revision_1() runs out the commits, and
2045                  * we are done computing the boundaries.
2046                  * switch to boundary commits output mode.
2047                  */
2048                 revs->boundary = 2;
2049
2050                 /*
2051                  * Update revs->commits to contain the list of
2052                  * boundary commits.
2053                  */
2054                 create_boundary_commit_list(revs);
2055
2056                 return get_revision_internal(revs);
2057         }
2058
2059         /*
2060          * boundary commits are the commits that are parents of the
2061          * ones we got from get_revision_1() but they themselves are
2062          * not returned from get_revision_1().  Before returning
2063          * 'c', we need to mark its parents that they could be boundaries.
2064          */
2065
2066         for (l = c->parents; l; l = l->next) {
2067                 struct object *p;
2068                 p = &(l->item->object);
2069                 if (p->flags & (CHILD_SHOWN | SHOWN))
2070                         continue;
2071                 p->flags |= CHILD_SHOWN;
2072                 gc_boundary(&revs->boundary_commits);
2073                 add_object_array(p, NULL, &revs->boundary_commits);
2074         }
2075
2076         return c;
2077 }
2078
2079 struct commit *get_revision(struct rev_info *revs)
2080 {
2081         struct commit *c;
2082         struct commit_list *reversed;
2083
2084         if (revs->reverse) {
2085                 reversed = NULL;
2086                 while ((c = get_revision_internal(revs))) {
2087                         commit_list_insert(c, &reversed);
2088                 }
2089                 revs->commits = reversed;
2090                 revs->reverse = 0;
2091                 revs->reverse_output_stage = 1;
2092         }
2093
2094         if (revs->reverse_output_stage)
2095                 return pop_commit(&revs->commits);
2096
2097         c = get_revision_internal(revs);
2098         if (c && revs->graph)
2099                 graph_update(revs->graph, c);
2100         return c;
2101 }