Merge branch 'en/t6036-merge-recursive-tests'
[git] / revision.c
1 #include "cache.h"
2 #include "object-store.h"
3 #include "tag.h"
4 #include "blob.h"
5 #include "tree.h"
6 #include "commit.h"
7 #include "diff.h"
8 #include "refs.h"
9 #include "revision.h"
10 #include "repository.h"
11 #include "graph.h"
12 #include "grep.h"
13 #include "reflog-walk.h"
14 #include "patch-ids.h"
15 #include "decorate.h"
16 #include "log-tree.h"
17 #include "string-list.h"
18 #include "line-log.h"
19 #include "mailmap.h"
20 #include "commit-slab.h"
21 #include "dir.h"
22 #include "cache-tree.h"
23 #include "bisect.h"
24 #include "packfile.h"
25 #include "worktree.h"
26 #include "argv-array.h"
27
28 volatile show_early_output_fn_t show_early_output;
29
30 static const char *term_bad;
31 static const char *term_good;
32
33 implement_shared_commit_slab(revision_sources, char *);
34
35 void show_object_with_name(FILE *out, struct object *obj, const char *name)
36 {
37         const char *p;
38
39         fprintf(out, "%s ", oid_to_hex(&obj->oid));
40         for (p = name; *p && *p != '\n'; p++)
41                 fputc(*p, out);
42         fputc('\n', out);
43 }
44
45 static void mark_blob_uninteresting(struct blob *blob)
46 {
47         if (!blob)
48                 return;
49         if (blob->object.flags & UNINTERESTING)
50                 return;
51         blob->object.flags |= UNINTERESTING;
52 }
53
54 static void mark_tree_contents_uninteresting(struct tree *tree)
55 {
56         struct tree_desc desc;
57         struct name_entry entry;
58
59         if (parse_tree_gently(tree, 1) < 0)
60                 return;
61
62         init_tree_desc(&desc, tree->buffer, tree->size);
63         while (tree_entry(&desc, &entry)) {
64                 switch (object_type(entry.mode)) {
65                 case OBJ_TREE:
66                         mark_tree_uninteresting(lookup_tree(the_repository, entry.oid));
67                         break;
68                 case OBJ_BLOB:
69                         mark_blob_uninteresting(lookup_blob(the_repository, entry.oid));
70                         break;
71                 default:
72                         /* Subproject commit - not in this repository */
73                         break;
74                 }
75         }
76
77         /*
78          * We don't care about the tree any more
79          * after it has been marked uninteresting.
80          */
81         free_tree_buffer(tree);
82 }
83
84 void mark_tree_uninteresting(struct tree *tree)
85 {
86         struct object *obj;
87
88         if (!tree)
89                 return;
90
91         obj = &tree->object;
92         if (obj->flags & UNINTERESTING)
93                 return;
94         obj->flags |= UNINTERESTING;
95         mark_tree_contents_uninteresting(tree);
96 }
97
98 struct commit_stack {
99         struct commit **items;
100         size_t nr, alloc;
101 };
102 #define COMMIT_STACK_INIT { NULL, 0, 0 }
103
104 static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
105 {
106         ALLOC_GROW(stack->items, stack->nr + 1, stack->alloc);
107         stack->items[stack->nr++] = commit;
108 }
109
110 static struct commit *commit_stack_pop(struct commit_stack *stack)
111 {
112         return stack->nr ? stack->items[--stack->nr] : NULL;
113 }
114
115 static void commit_stack_clear(struct commit_stack *stack)
116 {
117         FREE_AND_NULL(stack->items);
118         stack->nr = stack->alloc = 0;
119 }
120
121 static void mark_one_parent_uninteresting(struct commit *commit,
122                                           struct commit_stack *pending)
123 {
124         struct commit_list *l;
125
126         if (commit->object.flags & UNINTERESTING)
127                 return;
128         commit->object.flags |= UNINTERESTING;
129
130         /*
131          * Normally we haven't parsed the parent
132          * yet, so we won't have a parent of a parent
133          * here. However, it may turn out that we've
134          * reached this commit some other way (where it
135          * wasn't uninteresting), in which case we need
136          * to mark its parents recursively too..
137          */
138         for (l = commit->parents; l; l = l->next)
139                 commit_stack_push(pending, l->item);
140 }
141
142 void mark_parents_uninteresting(struct commit *commit)
143 {
144         struct commit_stack pending = COMMIT_STACK_INIT;
145         struct commit_list *l;
146
147         for (l = commit->parents; l; l = l->next)
148                 mark_one_parent_uninteresting(l->item, &pending);
149
150         while (pending.nr > 0)
151                 mark_one_parent_uninteresting(commit_stack_pop(&pending),
152                                               &pending);
153
154         commit_stack_clear(&pending);
155 }
156
157 static void add_pending_object_with_path(struct rev_info *revs,
158                                          struct object *obj,
159                                          const char *name, unsigned mode,
160                                          const char *path)
161 {
162         if (!obj)
163                 return;
164         if (revs->no_walk && (obj->flags & UNINTERESTING))
165                 revs->no_walk = 0;
166         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
167                 struct strbuf buf = STRBUF_INIT;
168                 int len = interpret_branch_name(name, 0, &buf, 0);
169
170                 if (0 < len && name[len] && buf.len)
171                         strbuf_addstr(&buf, name + len);
172                 add_reflog_for_walk(revs->reflog_info,
173                                     (struct commit *)obj,
174                                     buf.buf[0] ? buf.buf: name);
175                 strbuf_release(&buf);
176                 return; /* do not add the commit itself */
177         }
178         obj->flags |= USER_GIVEN;
179         add_object_array_with_path(obj, name, &revs->pending, mode, path);
180 }
181
182 static void add_pending_object_with_mode(struct rev_info *revs,
183                                          struct object *obj,
184                                          const char *name, unsigned mode)
185 {
186         add_pending_object_with_path(revs, obj, name, mode, NULL);
187 }
188
189 void add_pending_object(struct rev_info *revs,
190                         struct object *obj, const char *name)
191 {
192         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
193 }
194
195 void add_head_to_pending(struct rev_info *revs)
196 {
197         struct object_id oid;
198         struct object *obj;
199         if (get_oid("HEAD", &oid))
200                 return;
201         obj = parse_object(the_repository, &oid);
202         if (!obj)
203                 return;
204         add_pending_object(revs, obj, "HEAD");
205 }
206
207 static struct object *get_reference(struct rev_info *revs, const char *name,
208                                     const struct object_id *oid,
209                                     unsigned int flags)
210 {
211         struct object *object;
212
213         object = parse_object(the_repository, oid);
214         if (!object) {
215                 if (revs->ignore_missing)
216                         return object;
217                 if (revs->exclude_promisor_objects && is_promisor_object(oid))
218                         return NULL;
219                 die("bad object %s", name);
220         }
221         object->flags |= flags;
222         return object;
223 }
224
225 void add_pending_oid(struct rev_info *revs, const char *name,
226                       const struct object_id *oid, unsigned int flags)
227 {
228         struct object *object = get_reference(revs, name, oid, flags);
229         add_pending_object(revs, object, name);
230 }
231
232 static struct commit *handle_commit(struct rev_info *revs,
233                                     struct object_array_entry *entry)
234 {
235         struct object *object = entry->item;
236         const char *name = entry->name;
237         const char *path = entry->path;
238         unsigned int mode = entry->mode;
239         unsigned long flags = object->flags;
240
241         /*
242          * Tag object? Look what it points to..
243          */
244         while (object->type == OBJ_TAG) {
245                 struct tag *tag = (struct tag *) object;
246                 if (revs->tag_objects && !(flags & UNINTERESTING))
247                         add_pending_object(revs, object, tag->tag);
248                 if (!tag->tagged)
249                         die("bad tag");
250                 object = parse_object(the_repository, &tag->tagged->oid);
251                 if (!object) {
252                         if (revs->ignore_missing_links || (flags & UNINTERESTING))
253                                 return NULL;
254                         die("bad object %s", oid_to_hex(&tag->tagged->oid));
255                 }
256                 object->flags |= flags;
257                 /*
258                  * We'll handle the tagged object by looping or dropping
259                  * through to the non-tag handlers below. Do not
260                  * propagate path data from the tag's pending entry.
261                  */
262                 path = NULL;
263                 mode = 0;
264         }
265
266         /*
267          * Commit object? Just return it, we'll do all the complex
268          * reachability crud.
269          */
270         if (object->type == OBJ_COMMIT) {
271                 struct commit *commit = (struct commit *)object;
272
273                 if (parse_commit(commit) < 0)
274                         die("unable to parse commit %s", name);
275                 if (flags & UNINTERESTING) {
276                         mark_parents_uninteresting(commit);
277                         revs->limited = 1;
278                 }
279                 if (revs->sources) {
280                         char **slot = revision_sources_at(revs->sources, commit);
281
282                         if (!*slot)
283                                 *slot = xstrdup(name);
284                 }
285                 return commit;
286         }
287
288         /*
289          * Tree object? Either mark it uninteresting, or add it
290          * to the list of objects to look at later..
291          */
292         if (object->type == OBJ_TREE) {
293                 struct tree *tree = (struct tree *)object;
294                 if (!revs->tree_objects)
295                         return NULL;
296                 if (flags & UNINTERESTING) {
297                         mark_tree_contents_uninteresting(tree);
298                         return NULL;
299                 }
300                 add_pending_object_with_path(revs, object, name, mode, path);
301                 return NULL;
302         }
303
304         /*
305          * Blob object? You know the drill by now..
306          */
307         if (object->type == OBJ_BLOB) {
308                 if (!revs->blob_objects)
309                         return NULL;
310                 if (flags & UNINTERESTING)
311                         return NULL;
312                 add_pending_object_with_path(revs, object, name, mode, path);
313                 return NULL;
314         }
315         die("%s is unknown object", name);
316 }
317
318 static int everybody_uninteresting(struct commit_list *orig,
319                                    struct commit **interesting_cache)
320 {
321         struct commit_list *list = orig;
322
323         if (*interesting_cache) {
324                 struct commit *commit = *interesting_cache;
325                 if (!(commit->object.flags & UNINTERESTING))
326                         return 0;
327         }
328
329         while (list) {
330                 struct commit *commit = list->item;
331                 list = list->next;
332                 if (commit->object.flags & UNINTERESTING)
333                         continue;
334
335                 *interesting_cache = commit;
336                 return 0;
337         }
338         return 1;
339 }
340
341 /*
342  * A definition of "relevant" commit that we can use to simplify limited graphs
343  * by eliminating side branches.
344  *
345  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
346  * in our list), or that is a specified BOTTOM commit. Then after computing
347  * a limited list, during processing we can generally ignore boundary merges
348  * coming from outside the graph, (ie from irrelevant parents), and treat
349  * those merges as if they were single-parent. TREESAME is defined to consider
350  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
351  * we don't care if we were !TREESAME to non-graph parents.
352  *
353  * Treating bottom commits as relevant ensures that a limited graph's
354  * connection to the actual bottom commit is not viewed as a side branch, but
355  * treated as part of the graph. For example:
356  *
357  *   ....Z...A---X---o---o---B
358  *        .     /
359  *         W---Y
360  *
361  * When computing "A..B", the A-X connection is at least as important as
362  * Y-X, despite A being flagged UNINTERESTING.
363  *
364  * And when computing --ancestry-path "A..B", the A-X connection is more
365  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
366  */
367 static inline int relevant_commit(struct commit *commit)
368 {
369         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
370 }
371
372 /*
373  * Return a single relevant commit from a parent list. If we are a TREESAME
374  * commit, and this selects one of our parents, then we can safely simplify to
375  * that parent.
376  */
377 static struct commit *one_relevant_parent(const struct rev_info *revs,
378                                           struct commit_list *orig)
379 {
380         struct commit_list *list = orig;
381         struct commit *relevant = NULL;
382
383         if (!orig)
384                 return NULL;
385
386         /*
387          * For 1-parent commits, or if first-parent-only, then return that
388          * first parent (even if not "relevant" by the above definition).
389          * TREESAME will have been set purely on that parent.
390          */
391         if (revs->first_parent_only || !orig->next)
392                 return orig->item;
393
394         /*
395          * For multi-parent commits, identify a sole relevant parent, if any.
396          * If we have only one relevant parent, then TREESAME will be set purely
397          * with regard to that parent, and we can simplify accordingly.
398          *
399          * If we have more than one relevant parent, or no relevant parents
400          * (and multiple irrelevant ones), then we can't select a parent here
401          * and return NULL.
402          */
403         while (list) {
404                 struct commit *commit = list->item;
405                 list = list->next;
406                 if (relevant_commit(commit)) {
407                         if (relevant)
408                                 return NULL;
409                         relevant = commit;
410                 }
411         }
412         return relevant;
413 }
414
415 /*
416  * The goal is to get REV_TREE_NEW as the result only if the
417  * diff consists of all '+' (and no other changes), REV_TREE_OLD
418  * if the whole diff is removal of old data, and otherwise
419  * REV_TREE_DIFFERENT (of course if the trees are the same we
420  * want REV_TREE_SAME).
421  *
422  * The only time we care about the distinction is when
423  * remove_empty_trees is in effect, in which case we care only about
424  * whether the whole change is REV_TREE_NEW, or if there's another type
425  * of change. Which means we can stop the diff early in either of these
426  * cases:
427  *
428  *   1. We're not using remove_empty_trees at all.
429  *
430  *   2. We saw anything except REV_TREE_NEW.
431  */
432 static int tree_difference = REV_TREE_SAME;
433
434 static void file_add_remove(struct diff_options *options,
435                     int addremove, unsigned mode,
436                     const struct object_id *oid,
437                     int oid_valid,
438                     const char *fullpath, unsigned dirty_submodule)
439 {
440         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
441         struct rev_info *revs = options->change_fn_data;
442
443         tree_difference |= diff;
444         if (!revs->remove_empty_trees || tree_difference != REV_TREE_NEW)
445                 options->flags.has_changes = 1;
446 }
447
448 static void file_change(struct diff_options *options,
449                  unsigned old_mode, unsigned new_mode,
450                  const struct object_id *old_oid,
451                  const struct object_id *new_oid,
452                  int old_oid_valid, int new_oid_valid,
453                  const char *fullpath,
454                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
455 {
456         tree_difference = REV_TREE_DIFFERENT;
457         options->flags.has_changes = 1;
458 }
459
460 static int rev_compare_tree(struct rev_info *revs,
461                             struct commit *parent, struct commit *commit)
462 {
463         struct tree *t1 = get_commit_tree(parent);
464         struct tree *t2 = get_commit_tree(commit);
465
466         if (!t1)
467                 return REV_TREE_NEW;
468         if (!t2)
469                 return REV_TREE_OLD;
470
471         if (revs->simplify_by_decoration) {
472                 /*
473                  * If we are simplifying by decoration, then the commit
474                  * is worth showing if it has a tag pointing at it.
475                  */
476                 if (get_name_decoration(&commit->object))
477                         return REV_TREE_DIFFERENT;
478                 /*
479                  * A commit that is not pointed by a tag is uninteresting
480                  * if we are not limited by path.  This means that you will
481                  * see the usual "commits that touch the paths" plus any
482                  * tagged commit by specifying both --simplify-by-decoration
483                  * and pathspec.
484                  */
485                 if (!revs->prune_data.nr)
486                         return REV_TREE_SAME;
487         }
488
489         tree_difference = REV_TREE_SAME;
490         revs->pruning.flags.has_changes = 0;
491         if (diff_tree_oid(&t1->object.oid, &t2->object.oid, "",
492                            &revs->pruning) < 0)
493                 return REV_TREE_DIFFERENT;
494         return tree_difference;
495 }
496
497 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
498 {
499         int retval;
500         struct tree *t1 = get_commit_tree(commit);
501
502         if (!t1)
503                 return 0;
504
505         tree_difference = REV_TREE_SAME;
506         revs->pruning.flags.has_changes = 0;
507         retval = diff_tree_oid(NULL, &t1->object.oid, "", &revs->pruning);
508
509         return retval >= 0 && (tree_difference == REV_TREE_SAME);
510 }
511
512 struct treesame_state {
513         unsigned int nparents;
514         unsigned char treesame[FLEX_ARRAY];
515 };
516
517 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
518 {
519         unsigned n = commit_list_count(commit->parents);
520         struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
521         st->nparents = n;
522         add_decoration(&revs->treesame, &commit->object, st);
523         return st;
524 }
525
526 /*
527  * Must be called immediately after removing the nth_parent from a commit's
528  * parent list, if we are maintaining the per-parent treesame[] decoration.
529  * This does not recalculate the master TREESAME flag - update_treesame()
530  * should be called to update it after a sequence of treesame[] modifications
531  * that may have affected it.
532  */
533 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
534 {
535         struct treesame_state *st;
536         int old_same;
537
538         if (!commit->parents) {
539                 /*
540                  * Have just removed the only parent from a non-merge.
541                  * Different handling, as we lack decoration.
542                  */
543                 if (nth_parent != 0)
544                         die("compact_treesame %u", nth_parent);
545                 old_same = !!(commit->object.flags & TREESAME);
546                 if (rev_same_tree_as_empty(revs, commit))
547                         commit->object.flags |= TREESAME;
548                 else
549                         commit->object.flags &= ~TREESAME;
550                 return old_same;
551         }
552
553         st = lookup_decoration(&revs->treesame, &commit->object);
554         if (!st || nth_parent >= st->nparents)
555                 die("compact_treesame %u", nth_parent);
556
557         old_same = st->treesame[nth_parent];
558         memmove(st->treesame + nth_parent,
559                 st->treesame + nth_parent + 1,
560                 st->nparents - nth_parent - 1);
561
562         /*
563          * If we've just become a non-merge commit, update TREESAME
564          * immediately, and remove the no-longer-needed decoration.
565          * If still a merge, defer update until update_treesame().
566          */
567         if (--st->nparents == 1) {
568                 if (commit->parents->next)
569                         die("compact_treesame parents mismatch");
570                 if (st->treesame[0] && revs->dense)
571                         commit->object.flags |= TREESAME;
572                 else
573                         commit->object.flags &= ~TREESAME;
574                 free(add_decoration(&revs->treesame, &commit->object, NULL));
575         }
576
577         return old_same;
578 }
579
580 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
581 {
582         if (commit->parents && commit->parents->next) {
583                 unsigned n;
584                 struct treesame_state *st;
585                 struct commit_list *p;
586                 unsigned relevant_parents;
587                 unsigned relevant_change, irrelevant_change;
588
589                 st = lookup_decoration(&revs->treesame, &commit->object);
590                 if (!st)
591                         die("update_treesame %s", oid_to_hex(&commit->object.oid));
592                 relevant_parents = 0;
593                 relevant_change = irrelevant_change = 0;
594                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
595                         if (relevant_commit(p->item)) {
596                                 relevant_change |= !st->treesame[n];
597                                 relevant_parents++;
598                         } else
599                                 irrelevant_change |= !st->treesame[n];
600                 }
601                 if (relevant_parents ? relevant_change : irrelevant_change)
602                         commit->object.flags &= ~TREESAME;
603                 else
604                         commit->object.flags |= TREESAME;
605         }
606
607         return commit->object.flags & TREESAME;
608 }
609
610 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
611 {
612         /*
613          * TREESAME is irrelevant unless prune && dense;
614          * if simplify_history is set, we can't have a mixture of TREESAME and
615          *    !TREESAME INTERESTING parents (and we don't have treesame[]
616          *    decoration anyway);
617          * if first_parent_only is set, then the TREESAME flag is locked
618          *    against the first parent (and again we lack treesame[] decoration).
619          */
620         return revs->prune && revs->dense &&
621                !revs->simplify_history &&
622                !revs->first_parent_only;
623 }
624
625 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
626 {
627         struct commit_list **pp, *parent;
628         struct treesame_state *ts = NULL;
629         int relevant_change = 0, irrelevant_change = 0;
630         int relevant_parents, nth_parent;
631
632         /*
633          * If we don't do pruning, everything is interesting
634          */
635         if (!revs->prune)
636                 return;
637
638         if (!get_commit_tree(commit))
639                 return;
640
641         if (!commit->parents) {
642                 if (rev_same_tree_as_empty(revs, commit))
643                         commit->object.flags |= TREESAME;
644                 return;
645         }
646
647         /*
648          * Normal non-merge commit? If we don't want to make the
649          * history dense, we consider it always to be a change..
650          */
651         if (!revs->dense && !commit->parents->next)
652                 return;
653
654         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
655              (parent = *pp) != NULL;
656              pp = &parent->next, nth_parent++) {
657                 struct commit *p = parent->item;
658                 if (relevant_commit(p))
659                         relevant_parents++;
660
661                 if (nth_parent == 1) {
662                         /*
663                          * This our second loop iteration - so we now know
664                          * we're dealing with a merge.
665                          *
666                          * Do not compare with later parents when we care only about
667                          * the first parent chain, in order to avoid derailing the
668                          * traversal to follow a side branch that brought everything
669                          * in the path we are limited to by the pathspec.
670                          */
671                         if (revs->first_parent_only)
672                                 break;
673                         /*
674                          * If this will remain a potentially-simplifiable
675                          * merge, remember per-parent treesame if needed.
676                          * Initialise the array with the comparison from our
677                          * first iteration.
678                          */
679                         if (revs->treesame.name &&
680                             !revs->simplify_history &&
681                             !(commit->object.flags & UNINTERESTING)) {
682                                 ts = initialise_treesame(revs, commit);
683                                 if (!(irrelevant_change || relevant_change))
684                                         ts->treesame[0] = 1;
685                         }
686                 }
687                 if (parse_commit(p) < 0)
688                         die("cannot simplify commit %s (because of %s)",
689                             oid_to_hex(&commit->object.oid),
690                             oid_to_hex(&p->object.oid));
691                 switch (rev_compare_tree(revs, p, commit)) {
692                 case REV_TREE_SAME:
693                         if (!revs->simplify_history || !relevant_commit(p)) {
694                                 /* Even if a merge with an uninteresting
695                                  * side branch brought the entire change
696                                  * we are interested in, we do not want
697                                  * to lose the other branches of this
698                                  * merge, so we just keep going.
699                                  */
700                                 if (ts)
701                                         ts->treesame[nth_parent] = 1;
702                                 continue;
703                         }
704                         parent->next = NULL;
705                         commit->parents = parent;
706                         commit->object.flags |= TREESAME;
707                         return;
708
709                 case REV_TREE_NEW:
710                         if (revs->remove_empty_trees &&
711                             rev_same_tree_as_empty(revs, p)) {
712                                 /* We are adding all the specified
713                                  * paths from this parent, so the
714                                  * history beyond this parent is not
715                                  * interesting.  Remove its parents
716                                  * (they are grandparents for us).
717                                  * IOW, we pretend this parent is a
718                                  * "root" commit.
719                                  */
720                                 if (parse_commit(p) < 0)
721                                         die("cannot simplify commit %s (invalid %s)",
722                                             oid_to_hex(&commit->object.oid),
723                                             oid_to_hex(&p->object.oid));
724                                 p->parents = NULL;
725                         }
726                 /* fallthrough */
727                 case REV_TREE_OLD:
728                 case REV_TREE_DIFFERENT:
729                         if (relevant_commit(p))
730                                 relevant_change = 1;
731                         else
732                                 irrelevant_change = 1;
733                         continue;
734                 }
735                 die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
736         }
737
738         /*
739          * TREESAME is straightforward for single-parent commits. For merge
740          * commits, it is most useful to define it so that "irrelevant"
741          * parents cannot make us !TREESAME - if we have any relevant
742          * parents, then we only consider TREESAMEness with respect to them,
743          * allowing irrelevant merges from uninteresting branches to be
744          * simplified away. Only if we have only irrelevant parents do we
745          * base TREESAME on them. Note that this logic is replicated in
746          * update_treesame, which should be kept in sync.
747          */
748         if (relevant_parents ? !relevant_change : !irrelevant_change)
749                 commit->object.flags |= TREESAME;
750 }
751
752 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
753                     struct commit_list *cached_base, struct commit_list **cache)
754 {
755         struct commit_list *new_entry;
756
757         if (cached_base && p->date < cached_base->item->date)
758                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
759         else
760                 new_entry = commit_list_insert_by_date(p, head);
761
762         if (cache && (!*cache || p->date < (*cache)->item->date))
763                 *cache = new_entry;
764 }
765
766 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
767                     struct commit_list **list, struct commit_list **cache_ptr)
768 {
769         struct commit_list *parent = commit->parents;
770         unsigned left_flag;
771         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
772
773         if (commit->object.flags & ADDED)
774                 return 0;
775         commit->object.flags |= ADDED;
776
777         if (revs->include_check &&
778             !revs->include_check(commit, revs->include_check_data))
779                 return 0;
780
781         /*
782          * If the commit is uninteresting, don't try to
783          * prune parents - we want the maximal uninteresting
784          * set.
785          *
786          * Normally we haven't parsed the parent
787          * yet, so we won't have a parent of a parent
788          * here. However, it may turn out that we've
789          * reached this commit some other way (where it
790          * wasn't uninteresting), in which case we need
791          * to mark its parents recursively too..
792          */
793         if (commit->object.flags & UNINTERESTING) {
794                 while (parent) {
795                         struct commit *p = parent->item;
796                         parent = parent->next;
797                         if (p)
798                                 p->object.flags |= UNINTERESTING;
799                         if (parse_commit_gently(p, 1) < 0)
800                                 continue;
801                         if (p->parents)
802                                 mark_parents_uninteresting(p);
803                         if (p->object.flags & SEEN)
804                                 continue;
805                         p->object.flags |= SEEN;
806                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
807                 }
808                 return 0;
809         }
810
811         /*
812          * Ok, the commit wasn't uninteresting. Try to
813          * simplify the commit history and find the parent
814          * that has no differences in the path set if one exists.
815          */
816         try_to_simplify_commit(revs, commit);
817
818         if (revs->no_walk)
819                 return 0;
820
821         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
822
823         for (parent = commit->parents; parent; parent = parent->next) {
824                 struct commit *p = parent->item;
825                 int gently = revs->ignore_missing_links ||
826                              revs->exclude_promisor_objects;
827                 if (parse_commit_gently(p, gently) < 0) {
828                         if (revs->exclude_promisor_objects &&
829                             is_promisor_object(&p->object.oid)) {
830                                 if (revs->first_parent_only)
831                                         break;
832                                 continue;
833                         }
834                         return -1;
835                 }
836                 if (revs->sources) {
837                         char **slot = revision_sources_at(revs->sources, p);
838
839                         if (!*slot)
840                                 *slot = *revision_sources_at(revs->sources, commit);
841                 }
842                 p->object.flags |= left_flag;
843                 if (!(p->object.flags & SEEN)) {
844                         p->object.flags |= SEEN;
845                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
846                 }
847                 if (revs->first_parent_only)
848                         break;
849         }
850         return 0;
851 }
852
853 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
854 {
855         struct commit_list *p;
856         int left_count = 0, right_count = 0;
857         int left_first;
858         struct patch_ids ids;
859         unsigned cherry_flag;
860
861         /* First count the commits on the left and on the right */
862         for (p = list; p; p = p->next) {
863                 struct commit *commit = p->item;
864                 unsigned flags = commit->object.flags;
865                 if (flags & BOUNDARY)
866                         ;
867                 else if (flags & SYMMETRIC_LEFT)
868                         left_count++;
869                 else
870                         right_count++;
871         }
872
873         if (!left_count || !right_count)
874                 return;
875
876         left_first = left_count < right_count;
877         init_patch_ids(&ids);
878         ids.diffopts.pathspec = revs->diffopt.pathspec;
879
880         /* Compute patch-ids for one side */
881         for (p = list; p; p = p->next) {
882                 struct commit *commit = p->item;
883                 unsigned flags = commit->object.flags;
884
885                 if (flags & BOUNDARY)
886                         continue;
887                 /*
888                  * If we have fewer left, left_first is set and we omit
889                  * commits on the right branch in this loop.  If we have
890                  * fewer right, we skip the left ones.
891                  */
892                 if (left_first != !!(flags & SYMMETRIC_LEFT))
893                         continue;
894                 add_commit_patch_id(commit, &ids);
895         }
896
897         /* either cherry_mark or cherry_pick are true */
898         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
899
900         /* Check the other side */
901         for (p = list; p; p = p->next) {
902                 struct commit *commit = p->item;
903                 struct patch_id *id;
904                 unsigned flags = commit->object.flags;
905
906                 if (flags & BOUNDARY)
907                         continue;
908                 /*
909                  * If we have fewer left, left_first is set and we omit
910                  * commits on the left branch in this loop.
911                  */
912                 if (left_first == !!(flags & SYMMETRIC_LEFT))
913                         continue;
914
915                 /*
916                  * Have we seen the same patch id?
917                  */
918                 id = has_commit_patch_id(commit, &ids);
919                 if (!id)
920                         continue;
921
922                 commit->object.flags |= cherry_flag;
923                 id->commit->object.flags |= cherry_flag;
924         }
925
926         free_patch_ids(&ids);
927 }
928
929 /* How many extra uninteresting commits we want to see.. */
930 #define SLOP 5
931
932 static int still_interesting(struct commit_list *src, timestamp_t date, int slop,
933                              struct commit **interesting_cache)
934 {
935         /*
936          * No source list at all? We're definitely done..
937          */
938         if (!src)
939                 return 0;
940
941         /*
942          * Does the destination list contain entries with a date
943          * before the source list? Definitely _not_ done.
944          */
945         if (date <= src->item->date)
946                 return SLOP;
947
948         /*
949          * Does the source list still have interesting commits in
950          * it? Definitely not done..
951          */
952         if (!everybody_uninteresting(src, interesting_cache))
953                 return SLOP;
954
955         /* Ok, we're closing in.. */
956         return slop-1;
957 }
958
959 /*
960  * "rev-list --ancestry-path A..B" computes commits that are ancestors
961  * of B but not ancestors of A but further limits the result to those
962  * that are descendants of A.  This takes the list of bottom commits and
963  * the result of "A..B" without --ancestry-path, and limits the latter
964  * further to the ones that can reach one of the commits in "bottom".
965  */
966 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
967 {
968         struct commit_list *p;
969         struct commit_list *rlist = NULL;
970         int made_progress;
971
972         /*
973          * Reverse the list so that it will be likely that we would
974          * process parents before children.
975          */
976         for (p = list; p; p = p->next)
977                 commit_list_insert(p->item, &rlist);
978
979         for (p = bottom; p; p = p->next)
980                 p->item->object.flags |= TMP_MARK;
981
982         /*
983          * Mark the ones that can reach bottom commits in "list",
984          * in a bottom-up fashion.
985          */
986         do {
987                 made_progress = 0;
988                 for (p = rlist; p; p = p->next) {
989                         struct commit *c = p->item;
990                         struct commit_list *parents;
991                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
992                                 continue;
993                         for (parents = c->parents;
994                              parents;
995                              parents = parents->next) {
996                                 if (!(parents->item->object.flags & TMP_MARK))
997                                         continue;
998                                 c->object.flags |= TMP_MARK;
999                                 made_progress = 1;
1000                                 break;
1001                         }
1002                 }
1003         } while (made_progress);
1004
1005         /*
1006          * NEEDSWORK: decide if we want to remove parents that are
1007          * not marked with TMP_MARK from commit->parents for commits
1008          * in the resulting list.  We may not want to do that, though.
1009          */
1010
1011         /*
1012          * The ones that are not marked with TMP_MARK are uninteresting
1013          */
1014         for (p = list; p; p = p->next) {
1015                 struct commit *c = p->item;
1016                 if (c->object.flags & TMP_MARK)
1017                         continue;
1018                 c->object.flags |= UNINTERESTING;
1019         }
1020
1021         /* We are done with the TMP_MARK */
1022         for (p = list; p; p = p->next)
1023                 p->item->object.flags &= ~TMP_MARK;
1024         for (p = bottom; p; p = p->next)
1025                 p->item->object.flags &= ~TMP_MARK;
1026         free_commit_list(rlist);
1027 }
1028
1029 /*
1030  * Before walking the history, keep the set of "negative" refs the
1031  * caller has asked to exclude.
1032  *
1033  * This is used to compute "rev-list --ancestry-path A..B", as we need
1034  * to filter the result of "A..B" further to the ones that can actually
1035  * reach A.
1036  */
1037 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1038 {
1039         struct commit_list *elem, *bottom = NULL;
1040         for (elem = list; elem; elem = elem->next)
1041                 if (elem->item->object.flags & BOTTOM)
1042                         commit_list_insert(elem->item, &bottom);
1043         return bottom;
1044 }
1045
1046 /* Assumes either left_only or right_only is set */
1047 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1048 {
1049         struct commit_list *p;
1050
1051         for (p = list; p; p = p->next) {
1052                 struct commit *commit = p->item;
1053
1054                 if (revs->right_only) {
1055                         if (commit->object.flags & SYMMETRIC_LEFT)
1056                                 commit->object.flags |= SHOWN;
1057                 } else  /* revs->left_only is set */
1058                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1059                                 commit->object.flags |= SHOWN;
1060         }
1061 }
1062
1063 static int limit_list(struct rev_info *revs)
1064 {
1065         int slop = SLOP;
1066         timestamp_t date = TIME_MAX;
1067         struct commit_list *list = revs->commits;
1068         struct commit_list *newlist = NULL;
1069         struct commit_list **p = &newlist;
1070         struct commit_list *bottom = NULL;
1071         struct commit *interesting_cache = NULL;
1072
1073         if (revs->ancestry_path) {
1074                 bottom = collect_bottom_commits(list);
1075                 if (!bottom)
1076                         die("--ancestry-path given but there are no bottom commits");
1077         }
1078
1079         while (list) {
1080                 struct commit *commit = pop_commit(&list);
1081                 struct object *obj = &commit->object;
1082                 show_early_output_fn_t show;
1083
1084                 if (commit == interesting_cache)
1085                         interesting_cache = NULL;
1086
1087                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1088                         obj->flags |= UNINTERESTING;
1089                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1090                         return -1;
1091                 if (obj->flags & UNINTERESTING) {
1092                         mark_parents_uninteresting(commit);
1093                         slop = still_interesting(list, date, slop, &interesting_cache);
1094                         if (slop)
1095                                 continue;
1096                         break;
1097                 }
1098                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1099                         continue;
1100                 date = commit->date;
1101                 p = &commit_list_insert(commit, p)->next;
1102
1103                 show = show_early_output;
1104                 if (!show)
1105                         continue;
1106
1107                 show(revs, newlist);
1108                 show_early_output = NULL;
1109         }
1110         if (revs->cherry_pick || revs->cherry_mark)
1111                 cherry_pick_list(newlist, revs);
1112
1113         if (revs->left_only || revs->right_only)
1114                 limit_left_right(newlist, revs);
1115
1116         if (bottom) {
1117                 limit_to_ancestry(bottom, newlist);
1118                 free_commit_list(bottom);
1119         }
1120
1121         /*
1122          * Check if any commits have become TREESAME by some of their parents
1123          * becoming UNINTERESTING.
1124          */
1125         if (limiting_can_increase_treesame(revs))
1126                 for (list = newlist; list; list = list->next) {
1127                         struct commit *c = list->item;
1128                         if (c->object.flags & (UNINTERESTING | TREESAME))
1129                                 continue;
1130                         update_treesame(revs, c);
1131                 }
1132
1133         revs->commits = newlist;
1134         return 0;
1135 }
1136
1137 /*
1138  * Add an entry to refs->cmdline with the specified information.
1139  * *name is copied.
1140  */
1141 static void add_rev_cmdline(struct rev_info *revs,
1142                             struct object *item,
1143                             const char *name,
1144                             int whence,
1145                             unsigned flags)
1146 {
1147         struct rev_cmdline_info *info = &revs->cmdline;
1148         unsigned int nr = info->nr;
1149
1150         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1151         info->rev[nr].item = item;
1152         info->rev[nr].name = xstrdup(name);
1153         info->rev[nr].whence = whence;
1154         info->rev[nr].flags = flags;
1155         info->nr++;
1156 }
1157
1158 static void add_rev_cmdline_list(struct rev_info *revs,
1159                                  struct commit_list *commit_list,
1160                                  int whence,
1161                                  unsigned flags)
1162 {
1163         while (commit_list) {
1164                 struct object *object = &commit_list->item->object;
1165                 add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
1166                                 whence, flags);
1167                 commit_list = commit_list->next;
1168         }
1169 }
1170
1171 struct all_refs_cb {
1172         int all_flags;
1173         int warned_bad_reflog;
1174         struct rev_info *all_revs;
1175         const char *name_for_errormsg;
1176         struct ref_store *refs;
1177 };
1178
1179 int ref_excluded(struct string_list *ref_excludes, const char *path)
1180 {
1181         struct string_list_item *item;
1182
1183         if (!ref_excludes)
1184                 return 0;
1185         for_each_string_list_item(item, ref_excludes) {
1186                 if (!wildmatch(item->string, path, 0))
1187                         return 1;
1188         }
1189         return 0;
1190 }
1191
1192 static int handle_one_ref(const char *path, const struct object_id *oid,
1193                           int flag, void *cb_data)
1194 {
1195         struct all_refs_cb *cb = cb_data;
1196         struct object *object;
1197
1198         if (ref_excluded(cb->all_revs->ref_excludes, path))
1199             return 0;
1200
1201         object = get_reference(cb->all_revs, path, oid, cb->all_flags);
1202         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1203         add_pending_oid(cb->all_revs, path, oid, cb->all_flags);
1204         return 0;
1205 }
1206
1207 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1208         unsigned flags)
1209 {
1210         cb->all_revs = revs;
1211         cb->all_flags = flags;
1212         revs->rev_input_given = 1;
1213         cb->refs = NULL;
1214 }
1215
1216 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1217 {
1218         if (*ref_excludes_p) {
1219                 string_list_clear(*ref_excludes_p, 0);
1220                 free(*ref_excludes_p);
1221         }
1222         *ref_excludes_p = NULL;
1223 }
1224
1225 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1226 {
1227         if (!*ref_excludes_p) {
1228                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1229                 (*ref_excludes_p)->strdup_strings = 1;
1230         }
1231         string_list_append(*ref_excludes_p, exclude);
1232 }
1233
1234 static void handle_refs(struct ref_store *refs,
1235                         struct rev_info *revs, unsigned flags,
1236                         int (*for_each)(struct ref_store *, each_ref_fn, void *))
1237 {
1238         struct all_refs_cb cb;
1239
1240         if (!refs) {
1241                 /* this could happen with uninitialized submodules */
1242                 return;
1243         }
1244
1245         init_all_refs_cb(&cb, revs, flags);
1246         for_each(refs, handle_one_ref, &cb);
1247 }
1248
1249 static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
1250 {
1251         struct all_refs_cb *cb = cb_data;
1252         if (!is_null_oid(oid)) {
1253                 struct object *o = parse_object(the_repository, oid);
1254                 if (o) {
1255                         o->flags |= cb->all_flags;
1256                         /* ??? CMDLINEFLAGS ??? */
1257                         add_pending_object(cb->all_revs, o, "");
1258                 }
1259                 else if (!cb->warned_bad_reflog) {
1260                         warning("reflog of '%s' references pruned commits",
1261                                 cb->name_for_errormsg);
1262                         cb->warned_bad_reflog = 1;
1263                 }
1264         }
1265 }
1266
1267 static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
1268                 const char *email, timestamp_t timestamp, int tz,
1269                 const char *message, void *cb_data)
1270 {
1271         handle_one_reflog_commit(ooid, cb_data);
1272         handle_one_reflog_commit(noid, cb_data);
1273         return 0;
1274 }
1275
1276 static int handle_one_reflog(const char *path, const struct object_id *oid,
1277                              int flag, void *cb_data)
1278 {
1279         struct all_refs_cb *cb = cb_data;
1280         cb->warned_bad_reflog = 0;
1281         cb->name_for_errormsg = path;
1282         refs_for_each_reflog_ent(cb->refs, path,
1283                                  handle_one_reflog_ent, cb_data);
1284         return 0;
1285 }
1286
1287 static void add_other_reflogs_to_pending(struct all_refs_cb *cb)
1288 {
1289         struct worktree **worktrees, **p;
1290
1291         worktrees = get_worktrees(0);
1292         for (p = worktrees; *p; p++) {
1293                 struct worktree *wt = *p;
1294
1295                 if (wt->is_current)
1296                         continue;
1297
1298                 cb->refs = get_worktree_ref_store(wt);
1299                 refs_for_each_reflog(cb->refs,
1300                                      handle_one_reflog,
1301                                      cb);
1302         }
1303         free_worktrees(worktrees);
1304 }
1305
1306 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1307 {
1308         struct all_refs_cb cb;
1309
1310         cb.all_revs = revs;
1311         cb.all_flags = flags;
1312         cb.refs = get_main_ref_store(the_repository);
1313         for_each_reflog(handle_one_reflog, &cb);
1314
1315         if (!revs->single_worktree)
1316                 add_other_reflogs_to_pending(&cb);
1317 }
1318
1319 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1320                            struct strbuf *path)
1321 {
1322         size_t baselen = path->len;
1323         int i;
1324
1325         if (it->entry_count >= 0) {
1326                 struct tree *tree = lookup_tree(the_repository, &it->oid);
1327                 add_pending_object_with_path(revs, &tree->object, "",
1328                                              040000, path->buf);
1329         }
1330
1331         for (i = 0; i < it->subtree_nr; i++) {
1332                 struct cache_tree_sub *sub = it->down[i];
1333                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1334                 add_cache_tree(sub->cache_tree, revs, path);
1335                 strbuf_setlen(path, baselen);
1336         }
1337
1338 }
1339
1340 static void do_add_index_objects_to_pending(struct rev_info *revs,
1341                                             struct index_state *istate)
1342 {
1343         int i;
1344
1345         for (i = 0; i < istate->cache_nr; i++) {
1346                 struct cache_entry *ce = istate->cache[i];
1347                 struct blob *blob;
1348
1349                 if (S_ISGITLINK(ce->ce_mode))
1350                         continue;
1351
1352                 blob = lookup_blob(the_repository, &ce->oid);
1353                 if (!blob)
1354                         die("unable to add index blob to traversal");
1355                 add_pending_object_with_path(revs, &blob->object, "",
1356                                              ce->ce_mode, ce->name);
1357         }
1358
1359         if (istate->cache_tree) {
1360                 struct strbuf path = STRBUF_INIT;
1361                 add_cache_tree(istate->cache_tree, revs, &path);
1362                 strbuf_release(&path);
1363         }
1364 }
1365
1366 void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
1367 {
1368         struct worktree **worktrees, **p;
1369
1370         read_cache();
1371         do_add_index_objects_to_pending(revs, &the_index);
1372
1373         if (revs->single_worktree)
1374                 return;
1375
1376         worktrees = get_worktrees(0);
1377         for (p = worktrees; *p; p++) {
1378                 struct worktree *wt = *p;
1379                 struct index_state istate = { NULL };
1380
1381                 if (wt->is_current)
1382                         continue; /* current index already taken care of */
1383
1384                 if (read_index_from(&istate,
1385                                     worktree_git_path(wt, "index"),
1386                                     get_worktree_git_dir(wt)) > 0)
1387                         do_add_index_objects_to_pending(revs, &istate);
1388                 discard_index(&istate);
1389         }
1390         free_worktrees(worktrees);
1391 }
1392
1393 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags,
1394                             int exclude_parent)
1395 {
1396         struct object_id oid;
1397         struct object *it;
1398         struct commit *commit;
1399         struct commit_list *parents;
1400         int parent_number;
1401         const char *arg = arg_;
1402
1403         if (*arg == '^') {
1404                 flags ^= UNINTERESTING | BOTTOM;
1405                 arg++;
1406         }
1407         if (get_oid_committish(arg, &oid))
1408                 return 0;
1409         while (1) {
1410                 it = get_reference(revs, arg, &oid, 0);
1411                 if (!it && revs->ignore_missing)
1412                         return 0;
1413                 if (it->type != OBJ_TAG)
1414                         break;
1415                 if (!((struct tag*)it)->tagged)
1416                         return 0;
1417                 oidcpy(&oid, &((struct tag*)it)->tagged->oid);
1418         }
1419         if (it->type != OBJ_COMMIT)
1420                 return 0;
1421         commit = (struct commit *)it;
1422         if (exclude_parent &&
1423             exclude_parent > commit_list_count(commit->parents))
1424                 return 0;
1425         for (parents = commit->parents, parent_number = 1;
1426              parents;
1427              parents = parents->next, parent_number++) {
1428                 if (exclude_parent && parent_number != exclude_parent)
1429                         continue;
1430
1431                 it = &parents->item->object;
1432                 it->flags |= flags;
1433                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1434                 add_pending_object(revs, it, arg);
1435         }
1436         return 1;
1437 }
1438
1439 void init_revisions(struct rev_info *revs, const char *prefix)
1440 {
1441         memset(revs, 0, sizeof(*revs));
1442
1443         revs->abbrev = DEFAULT_ABBREV;
1444         revs->ignore_merges = 1;
1445         revs->simplify_history = 1;
1446         revs->pruning.flags.recursive = 1;
1447         revs->pruning.flags.quick = 1;
1448         revs->pruning.add_remove = file_add_remove;
1449         revs->pruning.change = file_change;
1450         revs->pruning.change_fn_data = revs;
1451         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1452         revs->dense = 1;
1453         revs->prefix = prefix;
1454         revs->max_age = -1;
1455         revs->min_age = -1;
1456         revs->skip_count = -1;
1457         revs->max_count = -1;
1458         revs->max_parents = -1;
1459         revs->expand_tabs_in_log = -1;
1460
1461         revs->commit_format = CMIT_FMT_DEFAULT;
1462         revs->expand_tabs_in_log_default = 8;
1463
1464         init_grep_defaults();
1465         grep_init(&revs->grep_filter, prefix);
1466         revs->grep_filter.status_only = 1;
1467
1468         diff_setup(&revs->diffopt);
1469         if (prefix && !revs->diffopt.prefix) {
1470                 revs->diffopt.prefix = prefix;
1471                 revs->diffopt.prefix_length = strlen(prefix);
1472         }
1473
1474         revs->notes_opt.use_default_notes = -1;
1475 }
1476
1477 static void add_pending_commit_list(struct rev_info *revs,
1478                                     struct commit_list *commit_list,
1479                                     unsigned int flags)
1480 {
1481         while (commit_list) {
1482                 struct object *object = &commit_list->item->object;
1483                 object->flags |= flags;
1484                 add_pending_object(revs, object, oid_to_hex(&object->oid));
1485                 commit_list = commit_list->next;
1486         }
1487 }
1488
1489 static void prepare_show_merge(struct rev_info *revs)
1490 {
1491         struct commit_list *bases;
1492         struct commit *head, *other;
1493         struct object_id oid;
1494         const char **prune = NULL;
1495         int i, prune_num = 1; /* counting terminating NULL */
1496
1497         if (get_oid("HEAD", &oid))
1498                 die("--merge without HEAD?");
1499         head = lookup_commit_or_die(&oid, "HEAD");
1500         if (get_oid("MERGE_HEAD", &oid))
1501                 die("--merge without MERGE_HEAD?");
1502         other = lookup_commit_or_die(&oid, "MERGE_HEAD");
1503         add_pending_object(revs, &head->object, "HEAD");
1504         add_pending_object(revs, &other->object, "MERGE_HEAD");
1505         bases = get_merge_bases(head, other);
1506         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1507         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1508         free_commit_list(bases);
1509         head->object.flags |= SYMMETRIC_LEFT;
1510
1511         if (!active_nr)
1512                 read_cache();
1513         for (i = 0; i < active_nr; i++) {
1514                 const struct cache_entry *ce = active_cache[i];
1515                 if (!ce_stage(ce))
1516                         continue;
1517                 if (ce_path_match(ce, &revs->prune_data, NULL)) {
1518                         prune_num++;
1519                         REALLOC_ARRAY(prune, prune_num);
1520                         prune[prune_num-2] = ce->name;
1521                         prune[prune_num-1] = NULL;
1522                 }
1523                 while ((i+1 < active_nr) &&
1524                        ce_same_name(ce, active_cache[i+1]))
1525                         i++;
1526         }
1527         clear_pathspec(&revs->prune_data);
1528         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1529                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1530         revs->limited = 1;
1531 }
1532
1533 static int dotdot_missing(const char *arg, char *dotdot,
1534                           struct rev_info *revs, int symmetric)
1535 {
1536         if (revs->ignore_missing)
1537                 return 0;
1538         /* de-munge so we report the full argument */
1539         *dotdot = '.';
1540         die(symmetric
1541             ? "Invalid symmetric difference expression %s"
1542             : "Invalid revision range %s", arg);
1543 }
1544
1545 static int handle_dotdot_1(const char *arg, char *dotdot,
1546                            struct rev_info *revs, int flags,
1547                            int cant_be_filename,
1548                            struct object_context *a_oc,
1549                            struct object_context *b_oc)
1550 {
1551         const char *a_name, *b_name;
1552         struct object_id a_oid, b_oid;
1553         struct object *a_obj, *b_obj;
1554         unsigned int a_flags, b_flags;
1555         int symmetric = 0;
1556         unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1557         unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;
1558
1559         a_name = arg;
1560         if (!*a_name)
1561                 a_name = "HEAD";
1562
1563         b_name = dotdot + 2;
1564         if (*b_name == '.') {
1565                 symmetric = 1;
1566                 b_name++;
1567         }
1568         if (!*b_name)
1569                 b_name = "HEAD";
1570
1571         if (get_oid_with_context(a_name, oc_flags, &a_oid, a_oc) ||
1572             get_oid_with_context(b_name, oc_flags, &b_oid, b_oc))
1573                 return -1;
1574
1575         if (!cant_be_filename) {
1576                 *dotdot = '.';
1577                 verify_non_filename(revs->prefix, arg);
1578                 *dotdot = '\0';
1579         }
1580
1581         a_obj = parse_object(the_repository, &a_oid);
1582         b_obj = parse_object(the_repository, &b_oid);
1583         if (!a_obj || !b_obj)
1584                 return dotdot_missing(arg, dotdot, revs, symmetric);
1585
1586         if (!symmetric) {
1587                 /* just A..B */
1588                 b_flags = flags;
1589                 a_flags = flags_exclude;
1590         } else {
1591                 /* A...B -- find merge bases between the two */
1592                 struct commit *a, *b;
1593                 struct commit_list *exclude;
1594
1595                 a = lookup_commit_reference(the_repository, &a_obj->oid);
1596                 b = lookup_commit_reference(the_repository, &b_obj->oid);
1597                 if (!a || !b)
1598                         return dotdot_missing(arg, dotdot, revs, symmetric);
1599
1600                 exclude = get_merge_bases(a, b);
1601                 add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
1602                                      flags_exclude);
1603                 add_pending_commit_list(revs, exclude, flags_exclude);
1604                 free_commit_list(exclude);
1605
1606                 b_flags = flags;
1607                 a_flags = flags | SYMMETRIC_LEFT;
1608         }
1609
1610         a_obj->flags |= a_flags;
1611         b_obj->flags |= b_flags;
1612         add_rev_cmdline(revs, a_obj, a_name, REV_CMD_LEFT, a_flags);
1613         add_rev_cmdline(revs, b_obj, b_name, REV_CMD_RIGHT, b_flags);
1614         add_pending_object_with_path(revs, a_obj, a_name, a_oc->mode, a_oc->path);
1615         add_pending_object_with_path(revs, b_obj, b_name, b_oc->mode, b_oc->path);
1616         return 0;
1617 }
1618
1619 static int handle_dotdot(const char *arg,
1620                          struct rev_info *revs, int flags,
1621                          int cant_be_filename)
1622 {
1623         struct object_context a_oc, b_oc;
1624         char *dotdot = strstr(arg, "..");
1625         int ret;
1626
1627         if (!dotdot)
1628                 return -1;
1629
1630         memset(&a_oc, 0, sizeof(a_oc));
1631         memset(&b_oc, 0, sizeof(b_oc));
1632
1633         *dotdot = '\0';
1634         ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
1635                               &a_oc, &b_oc);
1636         *dotdot = '.';
1637
1638         free(a_oc.path);
1639         free(b_oc.path);
1640
1641         return ret;
1642 }
1643
1644 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1645 {
1646         struct object_context oc;
1647         char *mark;
1648         struct object *object;
1649         struct object_id oid;
1650         int local_flags;
1651         const char *arg = arg_;
1652         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1653         unsigned get_sha1_flags = GET_OID_RECORD_PATH;
1654
1655         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1656
1657         if (!cant_be_filename && !strcmp(arg, "..")) {
1658                 /*
1659                  * Just ".."?  That is not a range but the
1660                  * pathspec for the parent directory.
1661                  */
1662                 return -1;
1663         }
1664
1665         if (!handle_dotdot(arg, revs, flags, revarg_opt))
1666                 return 0;
1667
1668         mark = strstr(arg, "^@");
1669         if (mark && !mark[2]) {
1670                 *mark = 0;
1671                 if (add_parents_only(revs, arg, flags, 0))
1672                         return 0;
1673                 *mark = '^';
1674         }
1675         mark = strstr(arg, "^!");
1676         if (mark && !mark[2]) {
1677                 *mark = 0;
1678                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
1679                         *mark = '^';
1680         }
1681         mark = strstr(arg, "^-");
1682         if (mark) {
1683                 int exclude_parent = 1;
1684
1685                 if (mark[2]) {
1686                         char *end;
1687                         exclude_parent = strtoul(mark + 2, &end, 10);
1688                         if (*end != '\0' || !exclude_parent)
1689                                 return -1;
1690                 }
1691
1692                 *mark = 0;
1693                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
1694                         *mark = '^';
1695         }
1696
1697         local_flags = 0;
1698         if (*arg == '^') {
1699                 local_flags = UNINTERESTING | BOTTOM;
1700                 arg++;
1701         }
1702
1703         if (revarg_opt & REVARG_COMMITTISH)
1704                 get_sha1_flags |= GET_OID_COMMITTISH;
1705
1706         if (get_oid_with_context(arg, get_sha1_flags, &oid, &oc))
1707                 return revs->ignore_missing ? 0 : -1;
1708         if (!cant_be_filename)
1709                 verify_non_filename(revs->prefix, arg);
1710         object = get_reference(revs, arg, &oid, flags ^ local_flags);
1711         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1712         add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
1713         free(oc.path);
1714         return 0;
1715 }
1716
1717 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1718                                      struct argv_array *prune)
1719 {
1720         while (strbuf_getline(sb, stdin) != EOF)
1721                 argv_array_push(prune, sb->buf);
1722 }
1723
1724 static void read_revisions_from_stdin(struct rev_info *revs,
1725                                       struct argv_array *prune)
1726 {
1727         struct strbuf sb;
1728         int seen_dashdash = 0;
1729         int save_warning;
1730
1731         save_warning = warn_on_object_refname_ambiguity;
1732         warn_on_object_refname_ambiguity = 0;
1733
1734         strbuf_init(&sb, 1000);
1735         while (strbuf_getline(&sb, stdin) != EOF) {
1736                 int len = sb.len;
1737                 if (!len)
1738                         break;
1739                 if (sb.buf[0] == '-') {
1740                         if (len == 2 && sb.buf[1] == '-') {
1741                                 seen_dashdash = 1;
1742                                 break;
1743                         }
1744                         die("options not supported in --stdin mode");
1745                 }
1746                 if (handle_revision_arg(sb.buf, revs, 0,
1747                                         REVARG_CANNOT_BE_FILENAME))
1748                         die("bad revision '%s'", sb.buf);
1749         }
1750         if (seen_dashdash)
1751                 read_pathspec_from_stdin(revs, &sb, prune);
1752
1753         strbuf_release(&sb);
1754         warn_on_object_refname_ambiguity = save_warning;
1755 }
1756
1757 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1758 {
1759         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1760 }
1761
1762 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1763 {
1764         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1765 }
1766
1767 static void add_message_grep(struct rev_info *revs, const char *pattern)
1768 {
1769         add_grep(revs, pattern, GREP_PATTERN_BODY);
1770 }
1771
1772 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1773                                int *unkc, const char **unkv)
1774 {
1775         const char *arg = argv[0];
1776         const char *optarg;
1777         int argcount;
1778         const unsigned hexsz = the_hash_algo->hexsz;
1779
1780         /* pseudo revision arguments */
1781         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1782             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1783             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1784             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1785             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1786             !strcmp(arg, "--indexed-objects") ||
1787             starts_with(arg, "--exclude=") ||
1788             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1789             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1790         {
1791                 unkv[(*unkc)++] = arg;
1792                 return 1;
1793         }
1794
1795         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1796                 revs->max_count = atoi(optarg);
1797                 revs->no_walk = 0;
1798                 return argcount;
1799         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1800                 revs->skip_count = atoi(optarg);
1801                 return argcount;
1802         } else if ((*arg == '-') && isdigit(arg[1])) {
1803                 /* accept -<digit>, like traditional "head" */
1804                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1805                     revs->max_count < 0)
1806                         die("'%s': not a non-negative integer", arg + 1);
1807                 revs->no_walk = 0;
1808         } else if (!strcmp(arg, "-n")) {
1809                 if (argc <= 1)
1810                         return error("-n requires an argument");
1811                 revs->max_count = atoi(argv[1]);
1812                 revs->no_walk = 0;
1813                 return 2;
1814         } else if (skip_prefix(arg, "-n", &optarg)) {
1815                 revs->max_count = atoi(optarg);
1816                 revs->no_walk = 0;
1817         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1818                 revs->max_age = atoi(optarg);
1819                 return argcount;
1820         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1821                 revs->max_age = approxidate(optarg);
1822                 return argcount;
1823         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1824                 revs->max_age = approxidate(optarg);
1825                 return argcount;
1826         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1827                 revs->min_age = atoi(optarg);
1828                 return argcount;
1829         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1830                 revs->min_age = approxidate(optarg);
1831                 return argcount;
1832         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1833                 revs->min_age = approxidate(optarg);
1834                 return argcount;
1835         } else if (!strcmp(arg, "--first-parent")) {
1836                 revs->first_parent_only = 1;
1837         } else if (!strcmp(arg, "--ancestry-path")) {
1838                 revs->ancestry_path = 1;
1839                 revs->simplify_history = 0;
1840                 revs->limited = 1;
1841         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1842                 init_reflog_walk(&revs->reflog_info);
1843         } else if (!strcmp(arg, "--default")) {
1844                 if (argc <= 1)
1845                         return error("bad --default argument");
1846                 revs->def = argv[1];
1847                 return 2;
1848         } else if (!strcmp(arg, "--merge")) {
1849                 revs->show_merge = 1;
1850         } else if (!strcmp(arg, "--topo-order")) {
1851                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1852                 revs->topo_order = 1;
1853         } else if (!strcmp(arg, "--simplify-merges")) {
1854                 revs->simplify_merges = 1;
1855                 revs->topo_order = 1;
1856                 revs->rewrite_parents = 1;
1857                 revs->simplify_history = 0;
1858                 revs->limited = 1;
1859         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1860                 revs->simplify_merges = 1;
1861                 revs->topo_order = 1;
1862                 revs->rewrite_parents = 1;
1863                 revs->simplify_history = 0;
1864                 revs->simplify_by_decoration = 1;
1865                 revs->limited = 1;
1866                 revs->prune = 1;
1867                 load_ref_decorations(NULL, DECORATE_SHORT_REFS);
1868         } else if (!strcmp(arg, "--date-order")) {
1869                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
1870                 revs->topo_order = 1;
1871         } else if (!strcmp(arg, "--author-date-order")) {
1872                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
1873                 revs->topo_order = 1;
1874         } else if (!strcmp(arg, "--early-output")) {
1875                 revs->early_output = 100;
1876                 revs->topo_order = 1;
1877         } else if (skip_prefix(arg, "--early-output=", &optarg)) {
1878                 if (strtoul_ui(optarg, 10, &revs->early_output) < 0)
1879                         die("'%s': not a non-negative integer", optarg);
1880                 revs->topo_order = 1;
1881         } else if (!strcmp(arg, "--parents")) {
1882                 revs->rewrite_parents = 1;
1883                 revs->print_parents = 1;
1884         } else if (!strcmp(arg, "--dense")) {
1885                 revs->dense = 1;
1886         } else if (!strcmp(arg, "--sparse")) {
1887                 revs->dense = 0;
1888         } else if (!strcmp(arg, "--in-commit-order")) {
1889                 revs->tree_blobs_in_commit_order = 1;
1890         } else if (!strcmp(arg, "--remove-empty")) {
1891                 revs->remove_empty_trees = 1;
1892         } else if (!strcmp(arg, "--merges")) {
1893                 revs->min_parents = 2;
1894         } else if (!strcmp(arg, "--no-merges")) {
1895                 revs->max_parents = 1;
1896         } else if (skip_prefix(arg, "--min-parents=", &optarg)) {
1897                 revs->min_parents = atoi(optarg);
1898         } else if (!strcmp(arg, "--no-min-parents")) {
1899                 revs->min_parents = 0;
1900         } else if (skip_prefix(arg, "--max-parents=", &optarg)) {
1901                 revs->max_parents = atoi(optarg);
1902         } else if (!strcmp(arg, "--no-max-parents")) {
1903                 revs->max_parents = -1;
1904         } else if (!strcmp(arg, "--boundary")) {
1905                 revs->boundary = 1;
1906         } else if (!strcmp(arg, "--left-right")) {
1907                 revs->left_right = 1;
1908         } else if (!strcmp(arg, "--left-only")) {
1909                 if (revs->right_only)
1910                         die("--left-only is incompatible with --right-only"
1911                             " or --cherry");
1912                 revs->left_only = 1;
1913         } else if (!strcmp(arg, "--right-only")) {
1914                 if (revs->left_only)
1915                         die("--right-only is incompatible with --left-only");
1916                 revs->right_only = 1;
1917         } else if (!strcmp(arg, "--cherry")) {
1918                 if (revs->left_only)
1919                         die("--cherry is incompatible with --left-only");
1920                 revs->cherry_mark = 1;
1921                 revs->right_only = 1;
1922                 revs->max_parents = 1;
1923                 revs->limited = 1;
1924         } else if (!strcmp(arg, "--count")) {
1925                 revs->count = 1;
1926         } else if (!strcmp(arg, "--cherry-mark")) {
1927                 if (revs->cherry_pick)
1928                         die("--cherry-mark is incompatible with --cherry-pick");
1929                 revs->cherry_mark = 1;
1930                 revs->limited = 1; /* needs limit_list() */
1931         } else if (!strcmp(arg, "--cherry-pick")) {
1932                 if (revs->cherry_mark)
1933                         die("--cherry-pick is incompatible with --cherry-mark");
1934                 revs->cherry_pick = 1;
1935                 revs->limited = 1;
1936         } else if (!strcmp(arg, "--objects")) {
1937                 revs->tag_objects = 1;
1938                 revs->tree_objects = 1;
1939                 revs->blob_objects = 1;
1940         } else if (!strcmp(arg, "--objects-edge")) {
1941                 revs->tag_objects = 1;
1942                 revs->tree_objects = 1;
1943                 revs->blob_objects = 1;
1944                 revs->edge_hint = 1;
1945         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
1946                 revs->tag_objects = 1;
1947                 revs->tree_objects = 1;
1948                 revs->blob_objects = 1;
1949                 revs->edge_hint = 1;
1950                 revs->edge_hint_aggressive = 1;
1951         } else if (!strcmp(arg, "--verify-objects")) {
1952                 revs->tag_objects = 1;
1953                 revs->tree_objects = 1;
1954                 revs->blob_objects = 1;
1955                 revs->verify_objects = 1;
1956         } else if (!strcmp(arg, "--unpacked")) {
1957                 revs->unpacked = 1;
1958         } else if (starts_with(arg, "--unpacked=")) {
1959                 die("--unpacked=<packfile> no longer supported.");
1960         } else if (!strcmp(arg, "-r")) {
1961                 revs->diff = 1;
1962                 revs->diffopt.flags.recursive = 1;
1963         } else if (!strcmp(arg, "-t")) {
1964                 revs->diff = 1;
1965                 revs->diffopt.flags.recursive = 1;
1966                 revs->diffopt.flags.tree_in_recursive = 1;
1967         } else if (!strcmp(arg, "-m")) {
1968                 revs->ignore_merges = 0;
1969         } else if (!strcmp(arg, "-c")) {
1970                 revs->diff = 1;
1971                 revs->dense_combined_merges = 0;
1972                 revs->combine_merges = 1;
1973         } else if (!strcmp(arg, "--cc")) {
1974                 revs->diff = 1;
1975                 revs->dense_combined_merges = 1;
1976                 revs->combine_merges = 1;
1977         } else if (!strcmp(arg, "-v")) {
1978                 revs->verbose_header = 1;
1979         } else if (!strcmp(arg, "--pretty")) {
1980                 revs->verbose_header = 1;
1981                 revs->pretty_given = 1;
1982                 get_commit_format(NULL, revs);
1983         } else if (skip_prefix(arg, "--pretty=", &optarg) ||
1984                    skip_prefix(arg, "--format=", &optarg)) {
1985                 /*
1986                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1987                  * not allowed, since the argument is optional.
1988                  */
1989                 revs->verbose_header = 1;
1990                 revs->pretty_given = 1;
1991                 get_commit_format(optarg, revs);
1992         } else if (!strcmp(arg, "--expand-tabs")) {
1993                 revs->expand_tabs_in_log = 8;
1994         } else if (!strcmp(arg, "--no-expand-tabs")) {
1995                 revs->expand_tabs_in_log = 0;
1996         } else if (skip_prefix(arg, "--expand-tabs=", &arg)) {
1997                 int val;
1998                 if (strtol_i(arg, 10, &val) < 0 || val < 0)
1999                         die("'%s': not a non-negative integer", arg);
2000                 revs->expand_tabs_in_log = val;
2001         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
2002                 revs->show_notes = 1;
2003                 revs->show_notes_given = 1;
2004                 revs->notes_opt.use_default_notes = 1;
2005         } else if (!strcmp(arg, "--show-signature")) {
2006                 revs->show_signature = 1;
2007         } else if (!strcmp(arg, "--no-show-signature")) {
2008                 revs->show_signature = 0;
2009         } else if (!strcmp(arg, "--show-linear-break")) {
2010                 revs->break_bar = "                    ..........";
2011                 revs->track_linear = 1;
2012                 revs->track_first_time = 1;
2013         } else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
2014                 revs->break_bar = xstrdup(optarg);
2015                 revs->track_linear = 1;
2016                 revs->track_first_time = 1;
2017         } else if (skip_prefix(arg, "--show-notes=", &optarg) ||
2018                    skip_prefix(arg, "--notes=", &optarg)) {
2019                 struct strbuf buf = STRBUF_INIT;
2020                 revs->show_notes = 1;
2021                 revs->show_notes_given = 1;
2022                 if (starts_with(arg, "--show-notes=") &&
2023                     revs->notes_opt.use_default_notes < 0)
2024                         revs->notes_opt.use_default_notes = 1;
2025                 strbuf_addstr(&buf, optarg);
2026                 expand_notes_ref(&buf);
2027                 string_list_append(&revs->notes_opt.extra_notes_refs,
2028                                    strbuf_detach(&buf, NULL));
2029         } else if (!strcmp(arg, "--no-notes")) {
2030                 revs->show_notes = 0;
2031                 revs->show_notes_given = 1;
2032                 revs->notes_opt.use_default_notes = -1;
2033                 /* we have been strdup'ing ourselves, so trick
2034                  * string_list into free()ing strings */
2035                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
2036                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
2037                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
2038         } else if (!strcmp(arg, "--standard-notes")) {
2039                 revs->show_notes_given = 1;
2040                 revs->notes_opt.use_default_notes = 1;
2041         } else if (!strcmp(arg, "--no-standard-notes")) {
2042                 revs->notes_opt.use_default_notes = 0;
2043         } else if (!strcmp(arg, "--oneline")) {
2044                 revs->verbose_header = 1;
2045                 get_commit_format("oneline", revs);
2046                 revs->pretty_given = 1;
2047                 revs->abbrev_commit = 1;
2048         } else if (!strcmp(arg, "--graph")) {
2049                 revs->topo_order = 1;
2050                 revs->rewrite_parents = 1;
2051                 revs->graph = graph_init(revs);
2052         } else if (!strcmp(arg, "--root")) {
2053                 revs->show_root_diff = 1;
2054         } else if (!strcmp(arg, "--no-commit-id")) {
2055                 revs->no_commit_id = 1;
2056         } else if (!strcmp(arg, "--always")) {
2057                 revs->always_show_header = 1;
2058         } else if (!strcmp(arg, "--no-abbrev")) {
2059                 revs->abbrev = 0;
2060         } else if (!strcmp(arg, "--abbrev")) {
2061                 revs->abbrev = DEFAULT_ABBREV;
2062         } else if (skip_prefix(arg, "--abbrev=", &optarg)) {
2063                 revs->abbrev = strtoul(optarg, NULL, 10);
2064                 if (revs->abbrev < MINIMUM_ABBREV)
2065                         revs->abbrev = MINIMUM_ABBREV;
2066                 else if (revs->abbrev > hexsz)
2067                         revs->abbrev = hexsz;
2068         } else if (!strcmp(arg, "--abbrev-commit")) {
2069                 revs->abbrev_commit = 1;
2070                 revs->abbrev_commit_given = 1;
2071         } else if (!strcmp(arg, "--no-abbrev-commit")) {
2072                 revs->abbrev_commit = 0;
2073         } else if (!strcmp(arg, "--full-diff")) {
2074                 revs->diff = 1;
2075                 revs->full_diff = 1;
2076         } else if (!strcmp(arg, "--full-history")) {
2077                 revs->simplify_history = 0;
2078         } else if (!strcmp(arg, "--relative-date")) {
2079                 revs->date_mode.type = DATE_RELATIVE;
2080                 revs->date_mode_explicit = 1;
2081         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
2082                 parse_date_format(optarg, &revs->date_mode);
2083                 revs->date_mode_explicit = 1;
2084                 return argcount;
2085         } else if (!strcmp(arg, "--log-size")) {
2086                 revs->show_log_size = 1;
2087         }
2088         /*
2089          * Grepping the commit log
2090          */
2091         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
2092                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
2093                 return argcount;
2094         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
2095                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
2096                 return argcount;
2097         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
2098                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
2099                 return argcount;
2100         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
2101                 add_message_grep(revs, optarg);
2102                 return argcount;
2103         } else if (!strcmp(arg, "--grep-debug")) {
2104                 revs->grep_filter.debug = 1;
2105         } else if (!strcmp(arg, "--basic-regexp")) {
2106                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_BRE;
2107         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
2108                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
2109         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
2110                 revs->grep_filter.ignore_case = 1;
2111                 revs->diffopt.pickaxe_opts |= DIFF_PICKAXE_IGNORE_CASE;
2112         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
2113                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
2114         } else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {
2115                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
2116         } else if (!strcmp(arg, "--all-match")) {
2117                 revs->grep_filter.all_match = 1;
2118         } else if (!strcmp(arg, "--invert-grep")) {
2119                 revs->invert_grep = 1;
2120         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
2121                 if (strcmp(optarg, "none"))
2122                         git_log_output_encoding = xstrdup(optarg);
2123                 else
2124                         git_log_output_encoding = "";
2125                 return argcount;
2126         } else if (!strcmp(arg, "--reverse")) {
2127                 revs->reverse ^= 1;
2128         } else if (!strcmp(arg, "--children")) {
2129                 revs->children.name = "children";
2130                 revs->limited = 1;
2131         } else if (!strcmp(arg, "--ignore-missing")) {
2132                 revs->ignore_missing = 1;
2133         } else if (!strcmp(arg, "--exclude-promisor-objects")) {
2134                 if (fetch_if_missing)
2135                         BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
2136                 revs->exclude_promisor_objects = 1;
2137         } else {
2138                 int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
2139                 if (!opts)
2140                         unkv[(*unkc)++] = arg;
2141                 return opts;
2142         }
2143         if (revs->graph && revs->track_linear)
2144                 die("--show-linear-break and --graph are incompatible");
2145
2146         return 1;
2147 }
2148
2149 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2150                         const struct option *options,
2151                         const char * const usagestr[])
2152 {
2153         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2154                                     &ctx->cpidx, ctx->out);
2155         if (n <= 0) {
2156                 error("unknown option `%s'", ctx->argv[0]);
2157                 usage_with_options(usagestr, options);
2158         }
2159         ctx->argv += n;
2160         ctx->argc -= n;
2161 }
2162
2163 static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
2164                                void *cb_data, const char *term)
2165 {
2166         struct strbuf bisect_refs = STRBUF_INIT;
2167         int status;
2168         strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
2169         status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data, 0);
2170         strbuf_release(&bisect_refs);
2171         return status;
2172 }
2173
2174 static int for_each_bad_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2175 {
2176         return for_each_bisect_ref(refs, fn, cb_data, term_bad);
2177 }
2178
2179 static int for_each_good_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2180 {
2181         return for_each_bisect_ref(refs, fn, cb_data, term_good);
2182 }
2183
2184 static int handle_revision_pseudo_opt(const char *submodule,
2185                                 struct rev_info *revs,
2186                                 int argc, const char **argv, int *flags)
2187 {
2188         const char *arg = argv[0];
2189         const char *optarg;
2190         struct ref_store *refs;
2191         int argcount;
2192
2193         if (submodule) {
2194                 /*
2195                  * We need some something like get_submodule_worktrees()
2196                  * before we can go through all worktrees of a submodule,
2197                  * .e.g with adding all HEADs from --all, which is not
2198                  * supported right now, so stick to single worktree.
2199                  */
2200                 if (!revs->single_worktree)
2201                         BUG("--single-worktree cannot be used together with submodule");
2202                 refs = get_submodule_ref_store(submodule);
2203         } else
2204                 refs = get_main_ref_store(the_repository);
2205
2206         /*
2207          * NOTE!
2208          *
2209          * Commands like "git shortlog" will not accept the options below
2210          * unless parse_revision_opt queues them (as opposed to erroring
2211          * out).
2212          *
2213          * When implementing your new pseudo-option, remember to
2214          * register it in the list at the top of handle_revision_opt.
2215          */
2216         if (!strcmp(arg, "--all")) {
2217                 handle_refs(refs, revs, *flags, refs_for_each_ref);
2218                 handle_refs(refs, revs, *flags, refs_head_ref);
2219                 if (!revs->single_worktree) {
2220                         struct all_refs_cb cb;
2221
2222                         init_all_refs_cb(&cb, revs, *flags);
2223                         other_head_refs(handle_one_ref, &cb);
2224                 }
2225                 clear_ref_exclusion(&revs->ref_excludes);
2226         } else if (!strcmp(arg, "--branches")) {
2227                 handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
2228                 clear_ref_exclusion(&revs->ref_excludes);
2229         } else if (!strcmp(arg, "--bisect")) {
2230                 read_bisect_terms(&term_bad, &term_good);
2231                 handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
2232                 handle_refs(refs, revs, *flags ^ (UNINTERESTING | BOTTOM),
2233                             for_each_good_bisect_ref);
2234                 revs->bisect = 1;
2235         } else if (!strcmp(arg, "--tags")) {
2236                 handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
2237                 clear_ref_exclusion(&revs->ref_excludes);
2238         } else if (!strcmp(arg, "--remotes")) {
2239                 handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
2240                 clear_ref_exclusion(&revs->ref_excludes);
2241         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2242                 struct all_refs_cb cb;
2243                 init_all_refs_cb(&cb, revs, *flags);
2244                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2245                 clear_ref_exclusion(&revs->ref_excludes);
2246                 return argcount;
2247         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2248                 add_ref_exclusion(&revs->ref_excludes, optarg);
2249                 return argcount;
2250         } else if (skip_prefix(arg, "--branches=", &optarg)) {
2251                 struct all_refs_cb cb;
2252                 init_all_refs_cb(&cb, revs, *flags);
2253                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/heads/", &cb);
2254                 clear_ref_exclusion(&revs->ref_excludes);
2255         } else if (skip_prefix(arg, "--tags=", &optarg)) {
2256                 struct all_refs_cb cb;
2257                 init_all_refs_cb(&cb, revs, *flags);
2258                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/tags/", &cb);
2259                 clear_ref_exclusion(&revs->ref_excludes);
2260         } else if (skip_prefix(arg, "--remotes=", &optarg)) {
2261                 struct all_refs_cb cb;
2262                 init_all_refs_cb(&cb, revs, *flags);
2263                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/remotes/", &cb);
2264                 clear_ref_exclusion(&revs->ref_excludes);
2265         } else if (!strcmp(arg, "--reflog")) {
2266                 add_reflogs_to_pending(revs, *flags);
2267         } else if (!strcmp(arg, "--indexed-objects")) {
2268                 add_index_objects_to_pending(revs, *flags);
2269         } else if (!strcmp(arg, "--not")) {
2270                 *flags ^= UNINTERESTING | BOTTOM;
2271         } else if (!strcmp(arg, "--no-walk")) {
2272                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2273         } else if (skip_prefix(arg, "--no-walk=", &optarg)) {
2274                 /*
2275                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2276                  * not allowed, since the argument is optional.
2277                  */
2278                 if (!strcmp(optarg, "sorted"))
2279                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2280                 else if (!strcmp(optarg, "unsorted"))
2281                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2282                 else
2283                         return error("invalid argument to --no-walk");
2284         } else if (!strcmp(arg, "--do-walk")) {
2285                 revs->no_walk = 0;
2286         } else if (!strcmp(arg, "--single-worktree")) {
2287                 revs->single_worktree = 1;
2288         } else {
2289                 return 0;
2290         }
2291
2292         return 1;
2293 }
2294
2295 static void NORETURN diagnose_missing_default(const char *def)
2296 {
2297         int flags;
2298         const char *refname;
2299
2300         refname = resolve_ref_unsafe(def, 0, NULL, &flags);
2301         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2302                 die(_("your current branch appears to be broken"));
2303
2304         skip_prefix(refname, "refs/heads/", &refname);
2305         die(_("your current branch '%s' does not have any commits yet"),
2306             refname);
2307 }
2308
2309 /*
2310  * Parse revision information, filling in the "rev_info" structure,
2311  * and removing the used arguments from the argument list.
2312  *
2313  * Returns the number of arguments left that weren't recognized
2314  * (which are also moved to the head of the argument list)
2315  */
2316 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2317 {
2318         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
2319         struct argv_array prune_data = ARGV_ARRAY_INIT;
2320         const char *submodule = NULL;
2321
2322         if (opt)
2323                 submodule = opt->submodule;
2324
2325         /* First, search for "--" */
2326         if (opt && opt->assume_dashdash) {
2327                 seen_dashdash = 1;
2328         } else {
2329                 seen_dashdash = 0;
2330                 for (i = 1; i < argc; i++) {
2331                         const char *arg = argv[i];
2332                         if (strcmp(arg, "--"))
2333                                 continue;
2334                         argv[i] = NULL;
2335                         argc = i;
2336                         if (argv[i + 1])
2337                                 argv_array_pushv(&prune_data, argv + i + 1);
2338                         seen_dashdash = 1;
2339                         break;
2340                 }
2341         }
2342
2343         /* Second, deal with arguments and options */
2344         flags = 0;
2345         revarg_opt = opt ? opt->revarg_opt : 0;
2346         if (seen_dashdash)
2347                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2348         read_from_stdin = 0;
2349         for (left = i = 1; i < argc; i++) {
2350                 const char *arg = argv[i];
2351                 if (*arg == '-') {
2352                         int opts;
2353
2354                         opts = handle_revision_pseudo_opt(submodule,
2355                                                 revs, argc - i, argv + i,
2356                                                 &flags);
2357                         if (opts > 0) {
2358                                 i += opts - 1;
2359                                 continue;
2360                         }
2361
2362                         if (!strcmp(arg, "--stdin")) {
2363                                 if (revs->disable_stdin) {
2364                                         argv[left++] = arg;
2365                                         continue;
2366                                 }
2367                                 if (read_from_stdin++)
2368                                         die("--stdin given twice?");
2369                                 read_revisions_from_stdin(revs, &prune_data);
2370                                 continue;
2371                         }
2372
2373                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2374                         if (opts > 0) {
2375                                 i += opts - 1;
2376                                 continue;
2377                         }
2378                         if (opts < 0)
2379                                 exit(128);
2380                         continue;
2381                 }
2382
2383
2384                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2385                         int j;
2386                         if (seen_dashdash || *arg == '^')
2387                                 die("bad revision '%s'", arg);
2388
2389                         /* If we didn't have a "--":
2390                          * (1) all filenames must exist;
2391                          * (2) all rev-args must not be interpretable
2392                          *     as a valid filename.
2393                          * but the latter we have checked in the main loop.
2394                          */
2395                         for (j = i; j < argc; j++)
2396                                 verify_filename(revs->prefix, argv[j], j == i);
2397
2398                         argv_array_pushv(&prune_data, argv + i);
2399                         break;
2400                 }
2401                 else
2402                         got_rev_arg = 1;
2403         }
2404
2405         if (prune_data.argc) {
2406                 /*
2407                  * If we need to introduce the magic "a lone ':' means no
2408                  * pathspec whatsoever", here is the place to do so.
2409                  *
2410                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2411                  *      prune_data.nr = 0;
2412                  *      prune_data.alloc = 0;
2413                  *      free(prune_data.path);
2414                  *      prune_data.path = NULL;
2415                  * } else {
2416                  *      terminate prune_data.alloc with NULL and
2417                  *      call init_pathspec() to set revs->prune_data here.
2418                  * }
2419                  */
2420                 parse_pathspec(&revs->prune_data, 0, 0,
2421                                revs->prefix, prune_data.argv);
2422         }
2423         argv_array_clear(&prune_data);
2424
2425         if (revs->def == NULL)
2426                 revs->def = opt ? opt->def : NULL;
2427         if (opt && opt->tweak)
2428                 opt->tweak(revs, opt);
2429         if (revs->show_merge)
2430                 prepare_show_merge(revs);
2431         if (revs->def && !revs->pending.nr && !revs->rev_input_given && !got_rev_arg) {
2432                 struct object_id oid;
2433                 struct object *object;
2434                 struct object_context oc;
2435                 if (get_oid_with_context(revs->def, 0, &oid, &oc))
2436                         diagnose_missing_default(revs->def);
2437                 object = get_reference(revs, revs->def, &oid, 0);
2438                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2439         }
2440
2441         /* Did the user ask for any diff output? Run the diff! */
2442         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2443                 revs->diff = 1;
2444
2445         /* Pickaxe, diff-filter and rename following need diffs */
2446         if ((revs->diffopt.pickaxe_opts & DIFF_PICKAXE_KINDS_MASK) ||
2447             revs->diffopt.filter ||
2448             revs->diffopt.flags.follow_renames)
2449                 revs->diff = 1;
2450
2451         if (revs->diffopt.objfind)
2452                 revs->simplify_history = 0;
2453
2454         if (revs->topo_order)
2455                 revs->limited = 1;
2456
2457         if (revs->prune_data.nr) {
2458                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2459                 /* Can't prune commits with rename following: the paths change.. */
2460                 if (!revs->diffopt.flags.follow_renames)
2461                         revs->prune = 1;
2462                 if (!revs->full_diff)
2463                         copy_pathspec(&revs->diffopt.pathspec,
2464                                       &revs->prune_data);
2465         }
2466         if (revs->combine_merges)
2467                 revs->ignore_merges = 0;
2468         revs->diffopt.abbrev = revs->abbrev;
2469
2470         if (revs->line_level_traverse) {
2471                 revs->limited = 1;
2472                 revs->topo_order = 1;
2473         }
2474
2475         diff_setup_done(&revs->diffopt);
2476
2477         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2478                                  &revs->grep_filter);
2479         compile_grep_patterns(&revs->grep_filter);
2480
2481         if (revs->reverse && revs->reflog_info)
2482                 die("cannot combine --reverse with --walk-reflogs");
2483         if (revs->reflog_info && revs->limited)
2484                 die("cannot combine --walk-reflogs with history-limiting options");
2485         if (revs->rewrite_parents && revs->children.name)
2486                 die("cannot combine --parents and --children");
2487
2488         /*
2489          * Limitations on the graph functionality
2490          */
2491         if (revs->reverse && revs->graph)
2492                 die("cannot combine --reverse with --graph");
2493
2494         if (revs->reflog_info && revs->graph)
2495                 die("cannot combine --walk-reflogs with --graph");
2496         if (revs->no_walk && revs->graph)
2497                 die("cannot combine --no-walk with --graph");
2498         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2499                 die("cannot use --grep-reflog without --walk-reflogs");
2500
2501         if (revs->first_parent_only && revs->bisect)
2502                 die(_("--first-parent is incompatible with --bisect"));
2503
2504         if (revs->expand_tabs_in_log < 0)
2505                 revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
2506
2507         return left;
2508 }
2509
2510 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2511 {
2512         struct commit_list *l = xcalloc(1, sizeof(*l));
2513
2514         l->item = child;
2515         l->next = add_decoration(&revs->children, &parent->object, l);
2516 }
2517
2518 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2519 {
2520         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2521         struct commit_list **pp, *p;
2522         int surviving_parents;
2523
2524         /* Examine existing parents while marking ones we have seen... */
2525         pp = &commit->parents;
2526         surviving_parents = 0;
2527         while ((p = *pp) != NULL) {
2528                 struct commit *parent = p->item;
2529                 if (parent->object.flags & TMP_MARK) {
2530                         *pp = p->next;
2531                         if (ts)
2532                                 compact_treesame(revs, commit, surviving_parents);
2533                         continue;
2534                 }
2535                 parent->object.flags |= TMP_MARK;
2536                 surviving_parents++;
2537                 pp = &p->next;
2538         }
2539         /* clear the temporary mark */
2540         for (p = commit->parents; p; p = p->next) {
2541                 p->item->object.flags &= ~TMP_MARK;
2542         }
2543         /* no update_treesame() - removing duplicates can't affect TREESAME */
2544         return surviving_parents;
2545 }
2546
2547 struct merge_simplify_state {
2548         struct commit *simplified;
2549 };
2550
2551 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2552 {
2553         struct merge_simplify_state *st;
2554
2555         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2556         if (!st) {
2557                 st = xcalloc(1, sizeof(*st));
2558                 add_decoration(&revs->merge_simplification, &commit->object, st);
2559         }
2560         return st;
2561 }
2562
2563 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2564 {
2565         struct commit_list *h = reduce_heads(commit->parents);
2566         int i = 0, marked = 0;
2567         struct commit_list *po, *pn;
2568
2569         /* Want these for sanity-checking only */
2570         int orig_cnt = commit_list_count(commit->parents);
2571         int cnt = commit_list_count(h);
2572
2573         /*
2574          * Not ready to remove items yet, just mark them for now, based
2575          * on the output of reduce_heads(). reduce_heads outputs the reduced
2576          * set in its original order, so this isn't too hard.
2577          */
2578         po = commit->parents;
2579         pn = h;
2580         while (po) {
2581                 if (pn && po->item == pn->item) {
2582                         pn = pn->next;
2583                         i++;
2584                 } else {
2585                         po->item->object.flags |= TMP_MARK;
2586                         marked++;
2587                 }
2588                 po=po->next;
2589         }
2590
2591         if (i != cnt || cnt+marked != orig_cnt)
2592                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2593
2594         free_commit_list(h);
2595
2596         return marked;
2597 }
2598
2599 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2600 {
2601         struct commit_list *p;
2602         int marked = 0;
2603
2604         for (p = commit->parents; p; p = p->next) {
2605                 struct commit *parent = p->item;
2606                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2607                         parent->object.flags |= TMP_MARK;
2608                         marked++;
2609                 }
2610         }
2611
2612         return marked;
2613 }
2614
2615 /*
2616  * Awkward naming - this means one parent we are TREESAME to.
2617  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2618  * empty tree). Better name suggestions?
2619  */
2620 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2621 {
2622         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2623         struct commit *unmarked = NULL, *marked = NULL;
2624         struct commit_list *p;
2625         unsigned n;
2626
2627         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2628                 if (ts->treesame[n]) {
2629                         if (p->item->object.flags & TMP_MARK) {
2630                                 if (!marked)
2631                                         marked = p->item;
2632                         } else {
2633                                 if (!unmarked) {
2634                                         unmarked = p->item;
2635                                         break;
2636                                 }
2637                         }
2638                 }
2639         }
2640
2641         /*
2642          * If we are TREESAME to a marked-for-deletion parent, but not to any
2643          * unmarked parents, unmark the first TREESAME parent. This is the
2644          * parent that the default simplify_history==1 scan would have followed,
2645          * and it doesn't make sense to omit that path when asking for a
2646          * simplified full history. Retaining it improves the chances of
2647          * understanding odd missed merges that took an old version of a file.
2648          *
2649          * Example:
2650          *
2651          *   I--------*X       A modified the file, but mainline merge X used
2652          *    \       /        "-s ours", so took the version from I. X is
2653          *     `-*A--'         TREESAME to I and !TREESAME to A.
2654          *
2655          * Default log from X would produce "I". Without this check,
2656          * --full-history --simplify-merges would produce "I-A-X", showing
2657          * the merge commit X and that it changed A, but not making clear that
2658          * it had just taken the I version. With this check, the topology above
2659          * is retained.
2660          *
2661          * Note that it is possible that the simplification chooses a different
2662          * TREESAME parent from the default, in which case this test doesn't
2663          * activate, and we _do_ drop the default parent. Example:
2664          *
2665          *   I------X         A modified the file, but it was reverted in B,
2666          *    \    /          meaning mainline merge X is TREESAME to both
2667          *    *A-*B           parents.
2668          *
2669          * Default log would produce "I" by following the first parent;
2670          * --full-history --simplify-merges will produce "I-A-B". But this is a
2671          * reasonable result - it presents a logical full history leading from
2672          * I to X, and X is not an important merge.
2673          */
2674         if (!unmarked && marked) {
2675                 marked->object.flags &= ~TMP_MARK;
2676                 return 1;
2677         }
2678
2679         return 0;
2680 }
2681
2682 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2683 {
2684         struct commit_list **pp, *p;
2685         int nth_parent, removed = 0;
2686
2687         pp = &commit->parents;
2688         nth_parent = 0;
2689         while ((p = *pp) != NULL) {
2690                 struct commit *parent = p->item;
2691                 if (parent->object.flags & TMP_MARK) {
2692                         parent->object.flags &= ~TMP_MARK;
2693                         *pp = p->next;
2694                         free(p);
2695                         removed++;
2696                         compact_treesame(revs, commit, nth_parent);
2697                         continue;
2698                 }
2699                 pp = &p->next;
2700                 nth_parent++;
2701         }
2702
2703         /* Removing parents can only increase TREESAMEness */
2704         if (removed && !(commit->object.flags & TREESAME))
2705                 update_treesame(revs, commit);
2706
2707         return nth_parent;
2708 }
2709
2710 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2711 {
2712         struct commit_list *p;
2713         struct commit *parent;
2714         struct merge_simplify_state *st, *pst;
2715         int cnt;
2716
2717         st = locate_simplify_state(revs, commit);
2718
2719         /*
2720          * Have we handled this one?
2721          */
2722         if (st->simplified)
2723                 return tail;
2724
2725         /*
2726          * An UNINTERESTING commit simplifies to itself, so does a
2727          * root commit.  We do not rewrite parents of such commit
2728          * anyway.
2729          */
2730         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2731                 st->simplified = commit;
2732                 return tail;
2733         }
2734
2735         /*
2736          * Do we know what commit all of our parents that matter
2737          * should be rewritten to?  Otherwise we are not ready to
2738          * rewrite this one yet.
2739          */
2740         for (cnt = 0, p = commit->parents; p; p = p->next) {
2741                 pst = locate_simplify_state(revs, p->item);
2742                 if (!pst->simplified) {
2743                         tail = &commit_list_insert(p->item, tail)->next;
2744                         cnt++;
2745                 }
2746                 if (revs->first_parent_only)
2747                         break;
2748         }
2749         if (cnt) {
2750                 tail = &commit_list_insert(commit, tail)->next;
2751                 return tail;
2752         }
2753
2754         /*
2755          * Rewrite our list of parents. Note that this cannot
2756          * affect our TREESAME flags in any way - a commit is
2757          * always TREESAME to its simplification.
2758          */
2759         for (p = commit->parents; p; p = p->next) {
2760                 pst = locate_simplify_state(revs, p->item);
2761                 p->item = pst->simplified;
2762                 if (revs->first_parent_only)
2763                         break;
2764         }
2765
2766         if (revs->first_parent_only)
2767                 cnt = 1;
2768         else
2769                 cnt = remove_duplicate_parents(revs, commit);
2770
2771         /*
2772          * It is possible that we are a merge and one side branch
2773          * does not have any commit that touches the given paths;
2774          * in such a case, the immediate parent from that branch
2775          * will be rewritten to be the merge base.
2776          *
2777          *      o----X          X: the commit we are looking at;
2778          *     /    /           o: a commit that touches the paths;
2779          * ---o----'
2780          *
2781          * Further, a merge of an independent branch that doesn't
2782          * touch the path will reduce to a treesame root parent:
2783          *
2784          *  ----o----X          X: the commit we are looking at;
2785          *          /           o: a commit that touches the paths;
2786          *         r            r: a root commit not touching the paths
2787          *
2788          * Detect and simplify both cases.
2789          */
2790         if (1 < cnt) {
2791                 int marked = mark_redundant_parents(revs, commit);
2792                 marked += mark_treesame_root_parents(revs, commit);
2793                 if (marked)
2794                         marked -= leave_one_treesame_to_parent(revs, commit);
2795                 if (marked)
2796                         cnt = remove_marked_parents(revs, commit);
2797         }
2798
2799         /*
2800          * A commit simplifies to itself if it is a root, if it is
2801          * UNINTERESTING, if it touches the given paths, or if it is a
2802          * merge and its parents don't simplify to one relevant commit
2803          * (the first two cases are already handled at the beginning of
2804          * this function).
2805          *
2806          * Otherwise, it simplifies to what its sole relevant parent
2807          * simplifies to.
2808          */
2809         if (!cnt ||
2810             (commit->object.flags & UNINTERESTING) ||
2811             !(commit->object.flags & TREESAME) ||
2812             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2813                 st->simplified = commit;
2814         else {
2815                 pst = locate_simplify_state(revs, parent);
2816                 st->simplified = pst->simplified;
2817         }
2818         return tail;
2819 }
2820
2821 static void simplify_merges(struct rev_info *revs)
2822 {
2823         struct commit_list *list, *next;
2824         struct commit_list *yet_to_do, **tail;
2825         struct commit *commit;
2826
2827         if (!revs->prune)
2828                 return;
2829
2830         /* feed the list reversed */
2831         yet_to_do = NULL;
2832         for (list = revs->commits; list; list = next) {
2833                 commit = list->item;
2834                 next = list->next;
2835                 /*
2836                  * Do not free(list) here yet; the original list
2837                  * is used later in this function.
2838                  */
2839                 commit_list_insert(commit, &yet_to_do);
2840         }
2841         while (yet_to_do) {
2842                 list = yet_to_do;
2843                 yet_to_do = NULL;
2844                 tail = &yet_to_do;
2845                 while (list) {
2846                         commit = pop_commit(&list);
2847                         tail = simplify_one(revs, commit, tail);
2848                 }
2849         }
2850
2851         /* clean up the result, removing the simplified ones */
2852         list = revs->commits;
2853         revs->commits = NULL;
2854         tail = &revs->commits;
2855         while (list) {
2856                 struct merge_simplify_state *st;
2857
2858                 commit = pop_commit(&list);
2859                 st = locate_simplify_state(revs, commit);
2860                 if (st->simplified == commit)
2861                         tail = &commit_list_insert(commit, tail)->next;
2862         }
2863 }
2864
2865 static void set_children(struct rev_info *revs)
2866 {
2867         struct commit_list *l;
2868         for (l = revs->commits; l; l = l->next) {
2869                 struct commit *commit = l->item;
2870                 struct commit_list *p;
2871
2872                 for (p = commit->parents; p; p = p->next)
2873                         add_child(revs, p->item, commit);
2874         }
2875 }
2876
2877 void reset_revision_walk(void)
2878 {
2879         clear_object_flags(SEEN | ADDED | SHOWN);
2880 }
2881
2882 static int mark_uninteresting(const struct object_id *oid,
2883                               struct packed_git *pack,
2884                               uint32_t pos,
2885                               void *unused)
2886 {
2887         struct object *o = parse_object(the_repository, oid);
2888         o->flags |= UNINTERESTING | SEEN;
2889         return 0;
2890 }
2891
2892 int prepare_revision_walk(struct rev_info *revs)
2893 {
2894         int i;
2895         struct object_array old_pending;
2896         struct commit_list **next = &revs->commits;
2897
2898         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
2899         revs->pending.nr = 0;
2900         revs->pending.alloc = 0;
2901         revs->pending.objects = NULL;
2902         for (i = 0; i < old_pending.nr; i++) {
2903                 struct object_array_entry *e = old_pending.objects + i;
2904                 struct commit *commit = handle_commit(revs, e);
2905                 if (commit) {
2906                         if (!(commit->object.flags & SEEN)) {
2907                                 commit->object.flags |= SEEN;
2908                                 next = commit_list_append(commit, next);
2909                         }
2910                 }
2911         }
2912         object_array_clear(&old_pending);
2913
2914         /* Signal whether we need per-parent treesame decoration */
2915         if (revs->simplify_merges ||
2916             (revs->limited && limiting_can_increase_treesame(revs)))
2917                 revs->treesame.name = "treesame";
2918
2919         if (revs->exclude_promisor_objects) {
2920                 for_each_packed_object(mark_uninteresting, NULL,
2921                                        FOR_EACH_OBJECT_PROMISOR_ONLY);
2922         }
2923
2924         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2925                 commit_list_sort_by_date(&revs->commits);
2926         if (revs->no_walk)
2927                 return 0;
2928         if (revs->limited)
2929                 if (limit_list(revs) < 0)
2930                         return -1;
2931         if (revs->topo_order)
2932                 sort_in_topological_order(&revs->commits, revs->sort_order);
2933         if (revs->line_level_traverse)
2934                 line_log_filter(revs);
2935         if (revs->simplify_merges)
2936                 simplify_merges(revs);
2937         if (revs->children.name)
2938                 set_children(revs);
2939         return 0;
2940 }
2941
2942 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2943 {
2944         struct commit_list *cache = NULL;
2945
2946         for (;;) {
2947                 struct commit *p = *pp;
2948                 if (!revs->limited)
2949                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2950                                 return rewrite_one_error;
2951                 if (p->object.flags & UNINTERESTING)
2952                         return rewrite_one_ok;
2953                 if (!(p->object.flags & TREESAME))
2954                         return rewrite_one_ok;
2955                 if (!p->parents)
2956                         return rewrite_one_noparents;
2957                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2958                         return rewrite_one_ok;
2959                 *pp = p;
2960         }
2961 }
2962
2963 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2964         rewrite_parent_fn_t rewrite_parent)
2965 {
2966         struct commit_list **pp = &commit->parents;
2967         while (*pp) {
2968                 struct commit_list *parent = *pp;
2969                 switch (rewrite_parent(revs, &parent->item)) {
2970                 case rewrite_one_ok:
2971                         break;
2972                 case rewrite_one_noparents:
2973                         *pp = parent->next;
2974                         continue;
2975                 case rewrite_one_error:
2976                         return -1;
2977                 }
2978                 pp = &parent->next;
2979         }
2980         remove_duplicate_parents(revs, commit);
2981         return 0;
2982 }
2983
2984 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2985 {
2986         char *person, *endp;
2987         size_t len, namelen, maillen;
2988         const char *name;
2989         const char *mail;
2990         struct ident_split ident;
2991
2992         person = strstr(buf->buf, what);
2993         if (!person)
2994                 return 0;
2995
2996         person += strlen(what);
2997         endp = strchr(person, '\n');
2998         if (!endp)
2999                 return 0;
3000
3001         len = endp - person;
3002
3003         if (split_ident_line(&ident, person, len))
3004                 return 0;
3005
3006         mail = ident.mail_begin;
3007         maillen = ident.mail_end - ident.mail_begin;
3008         name = ident.name_begin;
3009         namelen = ident.name_end - ident.name_begin;
3010
3011         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
3012                 struct strbuf namemail = STRBUF_INIT;
3013
3014                 strbuf_addf(&namemail, "%.*s <%.*s>",
3015                             (int)namelen, name, (int)maillen, mail);
3016
3017                 strbuf_splice(buf, ident.name_begin - buf->buf,
3018                               ident.mail_end - ident.name_begin + 1,
3019                               namemail.buf, namemail.len);
3020
3021                 strbuf_release(&namemail);
3022
3023                 return 1;
3024         }
3025
3026         return 0;
3027 }
3028
3029 static int commit_match(struct commit *commit, struct rev_info *opt)
3030 {
3031         int retval;
3032         const char *encoding;
3033         const char *message;
3034         struct strbuf buf = STRBUF_INIT;
3035
3036         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
3037                 return 1;
3038
3039         /* Prepend "fake" headers as needed */
3040         if (opt->grep_filter.use_reflog_filter) {
3041                 strbuf_addstr(&buf, "reflog ");
3042                 get_reflog_message(&buf, opt->reflog_info);
3043                 strbuf_addch(&buf, '\n');
3044         }
3045
3046         /*
3047          * We grep in the user's output encoding, under the assumption that it
3048          * is the encoding they are most likely to write their grep pattern
3049          * for. In addition, it means we will match the "notes" encoding below,
3050          * so we will not end up with a buffer that has two different encodings
3051          * in it.
3052          */
3053         encoding = get_log_output_encoding();
3054         message = logmsg_reencode(commit, NULL, encoding);
3055
3056         /* Copy the commit to temporary if we are using "fake" headers */
3057         if (buf.len)
3058                 strbuf_addstr(&buf, message);
3059
3060         if (opt->grep_filter.header_list && opt->mailmap) {
3061                 if (!buf.len)
3062                         strbuf_addstr(&buf, message);
3063
3064                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
3065                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
3066         }
3067
3068         /* Append "fake" message parts as needed */
3069         if (opt->show_notes) {
3070                 if (!buf.len)
3071                         strbuf_addstr(&buf, message);
3072                 format_display_notes(&commit->object.oid, &buf, encoding, 1);
3073         }
3074
3075         /*
3076          * Find either in the original commit message, or in the temporary.
3077          * Note that we cast away the constness of "message" here. It is
3078          * const because it may come from the cached commit buffer. That's OK,
3079          * because we know that it is modifiable heap memory, and that while
3080          * grep_buffer may modify it for speed, it will restore any
3081          * changes before returning.
3082          */
3083         if (buf.len)
3084                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
3085         else
3086                 retval = grep_buffer(&opt->grep_filter,
3087                                      (char *)message, strlen(message));
3088         strbuf_release(&buf);
3089         unuse_commit_buffer(commit, message);
3090         return opt->invert_grep ? !retval : retval;
3091 }
3092
3093 static inline int want_ancestry(const struct rev_info *revs)
3094 {
3095         return (revs->rewrite_parents || revs->children.name);
3096 }
3097
3098 /*
3099  * Return a timestamp to be used for --since/--until comparisons for this
3100  * commit, based on the revision options.
3101  */
3102 static timestamp_t comparison_date(const struct rev_info *revs,
3103                                    struct commit *commit)
3104 {
3105         return revs->reflog_info ?
3106                 get_reflog_timestamp(revs->reflog_info) :
3107                 commit->date;
3108 }
3109
3110 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
3111 {
3112         if (commit->object.flags & SHOWN)
3113                 return commit_ignore;
3114         if (revs->unpacked && has_object_pack(&commit->object.oid))
3115                 return commit_ignore;
3116         if (commit->object.flags & UNINTERESTING)
3117                 return commit_ignore;
3118         if (revs->min_age != -1 &&
3119             comparison_date(revs, commit) > revs->min_age)
3120                         return commit_ignore;
3121         if (revs->min_parents || (revs->max_parents >= 0)) {
3122                 int n = commit_list_count(commit->parents);
3123                 if ((n < revs->min_parents) ||
3124                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
3125                         return commit_ignore;
3126         }
3127         if (!commit_match(commit, revs))
3128                 return commit_ignore;
3129         if (revs->prune && revs->dense) {
3130                 /* Commit without changes? */
3131                 if (commit->object.flags & TREESAME) {
3132                         int n;
3133                         struct commit_list *p;
3134                         /* drop merges unless we want parenthood */
3135                         if (!want_ancestry(revs))
3136                                 return commit_ignore;
3137                         /*
3138                          * If we want ancestry, then need to keep any merges
3139                          * between relevant commits to tie together topology.
3140                          * For consistency with TREESAME and simplification
3141                          * use "relevant" here rather than just INTERESTING,
3142                          * to treat bottom commit(s) as part of the topology.
3143                          */
3144                         for (n = 0, p = commit->parents; p; p = p->next)
3145                                 if (relevant_commit(p->item))
3146                                         if (++n >= 2)
3147                                                 return commit_show;
3148                         return commit_ignore;
3149                 }
3150         }
3151         return commit_show;
3152 }
3153
3154 define_commit_slab(saved_parents, struct commit_list *);
3155
3156 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
3157
3158 /*
3159  * You may only call save_parents() once per commit (this is checked
3160  * for non-root commits).
3161  */
3162 static void save_parents(struct rev_info *revs, struct commit *commit)
3163 {
3164         struct commit_list **pp;
3165
3166         if (!revs->saved_parents_slab) {
3167                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
3168                 init_saved_parents(revs->saved_parents_slab);
3169         }
3170
3171         pp = saved_parents_at(revs->saved_parents_slab, commit);
3172
3173         /*
3174          * When walking with reflogs, we may visit the same commit
3175          * several times: once for each appearance in the reflog.
3176          *
3177          * In this case, save_parents() will be called multiple times.
3178          * We want to keep only the first set of parents.  We need to
3179          * store a sentinel value for an empty (i.e., NULL) parent
3180          * list to distinguish it from a not-yet-saved list, however.
3181          */
3182         if (*pp)
3183                 return;
3184         if (commit->parents)
3185                 *pp = copy_commit_list(commit->parents);
3186         else
3187                 *pp = EMPTY_PARENT_LIST;
3188 }
3189
3190 static void free_saved_parents(struct rev_info *revs)
3191 {
3192         if (revs->saved_parents_slab)
3193                 clear_saved_parents(revs->saved_parents_slab);
3194 }
3195
3196 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
3197 {
3198         struct commit_list *parents;
3199
3200         if (!revs->saved_parents_slab)
3201                 return commit->parents;
3202
3203         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3204         if (parents == EMPTY_PARENT_LIST)
3205                 return NULL;
3206         return parents;
3207 }
3208
3209 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3210 {
3211         enum commit_action action = get_commit_action(revs, commit);
3212
3213         if (action == commit_show &&
3214             revs->prune && revs->dense && want_ancestry(revs)) {
3215                 /*
3216                  * --full-diff on simplified parents is no good: it
3217                  * will show spurious changes from the commits that
3218                  * were elided.  So we save the parents on the side
3219                  * when --full-diff is in effect.
3220                  */
3221                 if (revs->full_diff)
3222                         save_parents(revs, commit);
3223                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3224                         return commit_error;
3225         }
3226         return action;
3227 }
3228
3229 static void track_linear(struct rev_info *revs, struct commit *commit)
3230 {
3231         if (revs->track_first_time) {
3232                 revs->linear = 1;
3233                 revs->track_first_time = 0;
3234         } else {
3235                 struct commit_list *p;
3236                 for (p = revs->previous_parents; p; p = p->next)
3237                         if (p->item == NULL || /* first commit */
3238                             !oidcmp(&p->item->object.oid, &commit->object.oid))
3239                                 break;
3240                 revs->linear = p != NULL;
3241         }
3242         if (revs->reverse) {
3243                 if (revs->linear)
3244                         commit->object.flags |= TRACK_LINEAR;
3245         }
3246         free_commit_list(revs->previous_parents);
3247         revs->previous_parents = copy_commit_list(commit->parents);
3248 }
3249
3250 static struct commit *get_revision_1(struct rev_info *revs)
3251 {
3252         while (1) {
3253                 struct commit *commit;
3254
3255                 if (revs->reflog_info)
3256                         commit = next_reflog_entry(revs->reflog_info);
3257                 else
3258                         commit = pop_commit(&revs->commits);
3259
3260                 if (!commit)
3261                         return NULL;
3262
3263                 if (revs->reflog_info)
3264                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3265
3266                 /*
3267                  * If we haven't done the list limiting, we need to look at
3268                  * the parents here. We also need to do the date-based limiting
3269                  * that we'd otherwise have done in limit_list().
3270                  */
3271                 if (!revs->limited) {
3272                         if (revs->max_age != -1 &&
3273                             comparison_date(revs, commit) < revs->max_age)
3274                                 continue;
3275
3276                         if (revs->reflog_info)
3277                                 try_to_simplify_commit(revs, commit);
3278                         else if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) {
3279                                 if (!revs->ignore_missing_links)
3280                                         die("Failed to traverse parents of commit %s",
3281                                                 oid_to_hex(&commit->object.oid));
3282                         }
3283                 }
3284
3285                 switch (simplify_commit(revs, commit)) {
3286                 case commit_ignore:
3287                         continue;
3288                 case commit_error:
3289                         die("Failed to simplify parents of commit %s",
3290                             oid_to_hex(&commit->object.oid));
3291                 default:
3292                         if (revs->track_linear)
3293                                 track_linear(revs, commit);
3294                         return commit;
3295                 }
3296         }
3297 }
3298
3299 /*
3300  * Return true for entries that have not yet been shown.  (This is an
3301  * object_array_each_func_t.)
3302  */
3303 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3304 {
3305         return !(entry->item->flags & SHOWN);
3306 }
3307
3308 /*
3309  * If array is on the verge of a realloc, garbage-collect any entries
3310  * that have already been shown to try to free up some space.
3311  */
3312 static void gc_boundary(struct object_array *array)
3313 {
3314         if (array->nr == array->alloc)
3315                 object_array_filter(array, entry_unshown, NULL);
3316 }
3317
3318 static void create_boundary_commit_list(struct rev_info *revs)
3319 {
3320         unsigned i;
3321         struct commit *c;
3322         struct object_array *array = &revs->boundary_commits;
3323         struct object_array_entry *objects = array->objects;
3324
3325         /*
3326          * If revs->commits is non-NULL at this point, an error occurred in
3327          * get_revision_1().  Ignore the error and continue printing the
3328          * boundary commits anyway.  (This is what the code has always
3329          * done.)
3330          */
3331         if (revs->commits) {
3332                 free_commit_list(revs->commits);
3333                 revs->commits = NULL;
3334         }
3335
3336         /*
3337          * Put all of the actual boundary commits from revs->boundary_commits
3338          * into revs->commits
3339          */
3340         for (i = 0; i < array->nr; i++) {
3341                 c = (struct commit *)(objects[i].item);
3342                 if (!c)
3343                         continue;
3344                 if (!(c->object.flags & CHILD_SHOWN))
3345                         continue;
3346                 if (c->object.flags & (SHOWN | BOUNDARY))
3347                         continue;
3348                 c->object.flags |= BOUNDARY;
3349                 commit_list_insert(c, &revs->commits);
3350         }
3351
3352         /*
3353          * If revs->topo_order is set, sort the boundary commits
3354          * in topological order
3355          */
3356         sort_in_topological_order(&revs->commits, revs->sort_order);
3357 }
3358
3359 static struct commit *get_revision_internal(struct rev_info *revs)
3360 {
3361         struct commit *c = NULL;
3362         struct commit_list *l;
3363
3364         if (revs->boundary == 2) {
3365                 /*
3366                  * All of the normal commits have already been returned,
3367                  * and we are now returning boundary commits.
3368                  * create_boundary_commit_list() has populated
3369                  * revs->commits with the remaining commits to return.
3370                  */
3371                 c = pop_commit(&revs->commits);
3372                 if (c)
3373                         c->object.flags |= SHOWN;
3374                 return c;
3375         }
3376
3377         /*
3378          * If our max_count counter has reached zero, then we are done. We
3379          * don't simply return NULL because we still might need to show
3380          * boundary commits. But we want to avoid calling get_revision_1, which
3381          * might do a considerable amount of work finding the next commit only
3382          * for us to throw it away.
3383          *
3384          * If it is non-zero, then either we don't have a max_count at all
3385          * (-1), or it is still counting, in which case we decrement.
3386          */
3387         if (revs->max_count) {
3388                 c = get_revision_1(revs);
3389                 if (c) {
3390                         while (revs->skip_count > 0) {
3391                                 revs->skip_count--;
3392                                 c = get_revision_1(revs);
3393                                 if (!c)
3394                                         break;
3395                         }
3396                 }
3397
3398                 if (revs->max_count > 0)
3399                         revs->max_count--;
3400         }
3401
3402         if (c)
3403                 c->object.flags |= SHOWN;
3404
3405         if (!revs->boundary)
3406                 return c;
3407
3408         if (!c) {
3409                 /*
3410                  * get_revision_1() runs out the commits, and
3411                  * we are done computing the boundaries.
3412                  * switch to boundary commits output mode.
3413                  */
3414                 revs->boundary = 2;
3415
3416                 /*
3417                  * Update revs->commits to contain the list of
3418                  * boundary commits.
3419                  */
3420                 create_boundary_commit_list(revs);
3421
3422                 return get_revision_internal(revs);
3423         }
3424
3425         /*
3426          * boundary commits are the commits that are parents of the
3427          * ones we got from get_revision_1() but they themselves are
3428          * not returned from get_revision_1().  Before returning
3429          * 'c', we need to mark its parents that they could be boundaries.
3430          */
3431
3432         for (l = c->parents; l; l = l->next) {
3433                 struct object *p;
3434                 p = &(l->item->object);
3435                 if (p->flags & (CHILD_SHOWN | SHOWN))
3436                         continue;
3437                 p->flags |= CHILD_SHOWN;
3438                 gc_boundary(&revs->boundary_commits);
3439                 add_object_array(p, NULL, &revs->boundary_commits);
3440         }
3441
3442         return c;
3443 }
3444
3445 struct commit *get_revision(struct rev_info *revs)
3446 {
3447         struct commit *c;
3448         struct commit_list *reversed;
3449
3450         if (revs->reverse) {
3451                 reversed = NULL;
3452                 while ((c = get_revision_internal(revs)))
3453                         commit_list_insert(c, &reversed);
3454                 revs->commits = reversed;
3455                 revs->reverse = 0;
3456                 revs->reverse_output_stage = 1;
3457         }
3458
3459         if (revs->reverse_output_stage) {
3460                 c = pop_commit(&revs->commits);
3461                 if (revs->track_linear)
3462                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3463                 return c;
3464         }
3465
3466         c = get_revision_internal(revs);
3467         if (c && revs->graph)
3468                 graph_update(revs->graph, c);
3469         if (!c) {
3470                 free_saved_parents(revs);
3471                 if (revs->previous_parents) {
3472                         free_commit_list(revs->previous_parents);
3473                         revs->previous_parents = NULL;
3474                 }
3475         }
3476         return c;
3477 }
3478
3479 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3480 {
3481         if (commit->object.flags & BOUNDARY)
3482                 return "-";
3483         else if (commit->object.flags & UNINTERESTING)
3484                 return "^";
3485         else if (commit->object.flags & PATCHSAME)
3486                 return "=";
3487         else if (!revs || revs->left_right) {
3488                 if (commit->object.flags & SYMMETRIC_LEFT)
3489                         return "<";
3490                 else
3491                         return ">";
3492         } else if (revs->graph)
3493                 return "*";
3494         else if (revs->cherry_mark)
3495                 return "+";
3496         return "";
3497 }
3498
3499 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3500 {
3501         char *mark = get_revision_mark(revs, commit);
3502         if (!strlen(mark))
3503                 return;
3504         fputs(mark, stdout);
3505         putchar(' ');
3506 }