/src/git/revision.c

Source
#define USE_THE_REPOSITORY_VARIABLE
#define DISABLE_SIGN_COMPARE_WARNINGS

#include "git-compat-util.h"
#include "config.h"
#include "environment.h"
#include "gettext.h"
#include "hex.h"
#include "object-name.h"
#include "object-file.h"
#include "odb.h"
#include "oidset.h"
#include "tag.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "diff.h"
#include "diff-merges.h"
#include "refs.h"
#include "revision.h"
#include "repository.h"
#include "graph.h"
#include "grep.h"
#include "reflog-walk.h"
#include "patch-ids.h"
#include "decorate.h"
#include "string-list.h"
#include "line-log.h"
#include "mailmap.h"
#include "commit-slab.h"
#include "cache-tree.h"
#include "bisect.h"
#include "packfile.h"
#include "worktree.h"
#include "path.h"
#include "read-cache.h"
#include "setup.h"
#include "sparse-index.h"
#include "strvec.h"
#include "trace2.h"
#include "commit-reach.h"
#include "commit-graph.h"
#include "prio-queue.h"
#include "hashmap.h"
#include "utf8.h"
#include "bloom.h"
#include "json-writer.h"
#include "list-objects-filter-options.h"
#include "resolve-undo.h"
#include "parse-options.h"
#include "wildmatch.h"

static char *term_bad;
static char *term_good;

implement_shared_commit_slab(revision_sources, char *);

static inline int want_ancestry(const struct rev_info *revs);

static void mark_blob_uninteresting(struct blob *blob)
{
  if (!blob)
    return;
  if (blob->object.flags & UNINTERESTING)
    return;
  blob->object.flags |= UNINTERESTING;
}

static void mark_tree_contents_uninteresting(struct repository *r,
               struct tree *tree)
{
  struct tree_desc desc;
  struct name_entry entry;

  if (parse_tree_gently(tree, 1) < 0)
    return;

  init_tree_desc(&desc, &tree->object.oid, tree->buffer, tree->size);
  while (tree_entry(&desc, &entry)) {
    switch (object_type(entry.mode)) {
    case OBJ_TREE:
      mark_tree_uninteresting(r, lookup_tree(r, &entry.oid));
      break;
    case OBJ_BLOB:
      mark_blob_uninteresting(lookup_blob(r, &entry.oid));
      break;
    default:
      /* Subproject commit - not in this repository */
      break;
    }
  }

  /*
   * We don't care about the tree any more
   * after it has been marked uninteresting.
   */
  free_tree_buffer(tree);
}

void mark_tree_uninteresting(struct repository *r, struct tree *tree)
{
  struct object *obj;

  if (!tree)
    return;

  obj = &tree->object;
  if (obj->flags & UNINTERESTING)
    return;
  obj->flags |= UNINTERESTING;
  mark_tree_contents_uninteresting(r, tree);
}

struct path_and_oids_entry {
  struct hashmap_entry ent;
  char *path;
  struct oidset trees;
};

static int path_and_oids_cmp(const void *hashmap_cmp_fn_data UNUSED,
           const struct hashmap_entry *eptr,
           const struct hashmap_entry *entry_or_key,
           const void *keydata UNUSED)
{
  const struct path_and_oids_entry *e1, *e2;

  e1 = container_of(eptr, const struct path_and_oids_entry, ent);
  e2 = container_of(entry_or_key, const struct path_and_oids_entry, ent);

  return strcmp(e1->path, e2->path);
}

static void paths_and_oids_clear(struct hashmap *map)
{
  struct hashmap_iter iter;
  struct path_and_oids_entry *entry;

  hashmap_for_each_entry(map, &iter, entry, ent /* member name */) {
    oidset_clear(&entry->trees);
    free(entry->path);
  }

  hashmap_clear_and_free(map, struct path_and_oids_entry, ent);
}

static void paths_and_oids_insert(struct hashmap *map,
          const char *path,
          const struct object_id *oid)
{
  int hash = strhash(path);
  struct path_and_oids_entry key;
  struct path_and_oids_entry *entry;

  hashmap_entry_init(&key.ent, hash);

  /* use a shallow copy for the lookup */
  key.path = (char *)path;
  oidset_init(&key.trees, 0);

  entry = hashmap_get_entry(map, &key, ent, NULL);
  if (!entry) {
    CALLOC_ARRAY(entry, 1);
    hashmap_entry_init(&entry->ent, hash);
    entry->path = xstrdup(key.path);
    oidset_init(&entry->trees, 16);
    hashmap_put(map, &entry->ent);
  }

  oidset_insert(&entry->trees, oid);
}

static void add_children_by_path(struct repository *r,
         struct tree *tree,
         struct hashmap *map)
{
  struct tree_desc desc;
  struct name_entry entry;

  if (!tree)
    return;

  if (parse_tree_gently(tree, 1) < 0)
    return;

  init_tree_desc(&desc, &tree->object.oid, tree->buffer, tree->size);
  while (tree_entry(&desc, &entry)) {
    switch (object_type(entry.mode)) {
    case OBJ_TREE:
      paths_and_oids_insert(map, entry.path, &entry.oid);

      if (tree->object.flags & UNINTERESTING) {
        struct tree *child = lookup_tree(r, &entry.oid);
        if (child)
          child->object.flags |= UNINTERESTING;
      }
      break;
    case OBJ_BLOB:
      if (tree->object.flags & UNINTERESTING) {
        struct blob *child = lookup_blob(r, &entry.oid);
        if (child)
          child->object.flags |= UNINTERESTING;
      }
      break;
    default:
      /* Subproject commit - not in this repository */
      break;
    }
  }

  free_tree_buffer(tree);
}

void mark_trees_uninteresting_sparse(struct repository *r,
             struct oidset *trees)
{
  unsigned has_interesting = 0, has_uninteresting = 0;
  struct hashmap map = HASHMAP_INIT(path_and_oids_cmp, NULL);
  struct hashmap_iter map_iter;
  struct path_and_oids_entry *entry;
  struct object_id *oid;
  struct oidset_iter iter;

  oidset_iter_init(trees, &iter);
  while ((!has_interesting || !has_uninteresting) &&
         (oid = oidset_iter_next(&iter))) {
    struct tree *tree = lookup_tree(r, oid);

    if (!tree)
      continue;

    if (tree->object.flags & UNINTERESTING)
      has_uninteresting = 1;
    else
      has_interesting = 1;
  }

  /* Do not walk unless we have both types of trees. */
  if (!has_uninteresting || !has_interesting)
    return;

  oidset_iter_init(trees, &iter);
  while ((oid = oidset_iter_next(&iter))) {
    struct tree *tree = lookup_tree(r, oid);
    add_children_by_path(r, tree, &map);
  }

  hashmap_for_each_entry(&map, &map_iter, entry, ent /* member name */)
    mark_trees_uninteresting_sparse(r, &entry->trees);

  paths_and_oids_clear(&map);
}

struct commit_stack {
  struct commit **items;
  size_t nr, alloc;
};
#define COMMIT_STACK_INIT { 0 }

static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
{
  ALLOC_GROW(stack->items, stack->nr + 1, stack->alloc);
  stack->items[stack->nr++] = commit;
}

static struct commit *commit_stack_pop(struct commit_stack *stack)
{
  return stack->nr ? stack->items[--stack->nr] : NULL;
}

static void commit_stack_clear(struct commit_stack *stack)
{
  FREE_AND_NULL(stack->items);
  stack->nr = stack->alloc = 0;
}

static void mark_one_parent_uninteresting(struct rev_info *revs, struct commit *commit,
            struct commit_stack *pending)
{
  struct commit_list *l;

  if (commit->object.flags & UNINTERESTING)
    return;
  commit->object.flags |= UNINTERESTING;

  /*
   * Normally we haven't parsed the parent
   * yet, so we won't have a parent of a parent
   * here. However, it may turn out that we've
   * reached this commit some other way (where it
   * wasn't uninteresting), in which case we need
   * to mark its parents recursively too..
   */
  for (l = commit->parents; l; l = l->next) {
    commit_stack_push(pending, l->item);
    if (revs && revs->exclude_first_parent_only)
      break;
  }
}

void mark_parents_uninteresting(struct rev_info *revs, struct commit *commit)
{
  struct commit_stack pending = COMMIT_STACK_INIT;
  struct commit_list *l;

  for (l = commit->parents; l; l = l->next) {
    mark_one_parent_uninteresting(revs, l->item, &pending);
    if (revs && revs->exclude_first_parent_only)
      break;
  }

  while (pending.nr > 0)
    mark_one_parent_uninteresting(revs, commit_stack_pop(&pending),
                &pending);

  commit_stack_clear(&pending);
}

static void add_pending_object_with_path(struct rev_info *revs,
           struct object *obj,
           const char *name, unsigned mode,
           const char *path)
{
  struct interpret_branch_name_options options = { 0 };
  if (!obj)
    return;
  if (revs->no_walk && (obj->flags & UNINTERESTING))
    revs->no_walk = 0;
  if (revs->reflog_info && obj->type == OBJ_COMMIT) {
    struct strbuf buf = STRBUF_INIT;
    size_t namelen = strlen(name);
    int len = repo_interpret_branch_name(the_repository, name,
                 namelen, &buf, &options);

    if (0 < len && len < namelen && buf.len)
      strbuf_addstr(&buf, name + len);
    add_reflog_for_walk(revs->reflog_info,
            (struct commit *)obj,
            buf.buf[0] ? buf.buf: name);
    strbuf_release(&buf);
    return; /* do not add the commit itself */
  }
  add_object_array_with_path(obj, name, &revs->pending, mode, path);
}

static void add_pending_object_with_mode(struct rev_info *revs,
           struct object *obj,
           const char *name, unsigned mode)
{
  add_pending_object_with_path(revs, obj, name, mode, NULL);
}

void add_pending_object(struct rev_info *revs,
      struct object *obj, const char *name)
{
  add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
}

void add_head_to_pending(struct rev_info *revs)
{
  struct object_id oid;
  struct object *obj;
  if (repo_get_oid(the_repository, "HEAD", &oid))
    return;
  obj = parse_object(revs->repo, &oid);
  if (!obj)
    return;
  add_pending_object(revs, obj, "HEAD");
}

static struct object *get_reference(struct rev_info *revs, const char *name,
            const struct object_id *oid,
            unsigned int flags)
{
  struct object *object;

  object = parse_object_with_flags(revs->repo, oid,
           revs->verify_objects ? 0 :
           PARSE_OBJECT_SKIP_HASH_CHECK |
           PARSE_OBJECT_DISCARD_TREE);

  if (!object) {
    if (revs->ignore_missing)
      return NULL;
    if (revs->exclude_promisor_objects &&
        is_promisor_object(revs->repo, oid))
      return NULL;
    if (revs->do_not_die_on_missing_objects) {
      oidset_insert(&revs->missing_commits, oid);
      return NULL;
    }
    die("bad object %s", name);
  }
  object->flags |= flags;
  return object;
}

void add_pending_oid(struct rev_info *revs, const char *name,
          const struct object_id *oid, unsigned int flags)
{
  struct object *object = get_reference(revs, name, oid, flags);
  add_pending_object(revs, object, name);
}

static struct commit *handle_commit(struct rev_info *revs,
            struct object_array_entry *entry)
{
  struct object *object = entry->item;
  const char *name = entry->name;
  const char *path = entry->path;
  unsigned int mode = entry->mode;
  unsigned long flags = object->flags;

  /*
   * Tag object? Look what it points to..
   */
  while (object->type == OBJ_TAG) {
    struct tag *tag = (struct tag *) object;
    struct object_id *oid;
    if (revs->tag_objects && !(flags & UNINTERESTING))
      add_pending_object(revs, object, tag->tag);
    oid = get_tagged_oid(tag);
    object = parse_object(revs->repo, oid);
    if (!object) {
      if (revs->ignore_missing_links || (flags & UNINTERESTING))
        return NULL;
      if (revs->exclude_promisor_objects &&
          is_promisor_object(revs->repo, &tag->tagged->oid))
        return NULL;
      if (revs->do_not_die_on_missing_objects && oid) {
        oidset_insert(&revs->missing_commits, oid);
        return NULL;
      }
      die("bad object %s", oid_to_hex(&tag->tagged->oid));
    }
    object->flags |= flags;
    /*
     * We'll handle the tagged object by looping or dropping
     * through to the non-tag handlers below. Do not
     * propagate path data from the tag's pending entry.
     */
    path = NULL;
    mode = 0;
  }

  /*
   * Commit object? Just return it, we'll do all the complex
   * reachability crud.
   */
  if (object->type == OBJ_COMMIT) {
    struct commit *commit = (struct commit *)object;

    if (repo_parse_commit(revs->repo, commit) < 0)
      die("unable to parse commit %s", name);
    if (flags & UNINTERESTING) {
      mark_parents_uninteresting(revs, commit);

      if (!revs->topo_order || !generation_numbers_enabled(the_repository))
        revs->limited = 1;
    }
    if (revs->sources) {
      char **slot = revision_sources_at(revs->sources, commit);

      if (!*slot)
        *slot = xstrdup(name);
    }
    return commit;
  }

  /*
   * Tree object? Either mark it uninteresting, or add it
   * to the list of objects to look at later..
   */
  if (object->type == OBJ_TREE) {
    struct tree *tree = (struct tree *)object;
    if (!revs->tree_objects)
      return NULL;
    if (flags & UNINTERESTING) {
      mark_tree_contents_uninteresting(revs->repo, tree);
      return NULL;
    }
    add_pending_object_with_path(revs, object, name, mode, path);
    return NULL;
  }

  /*
   * Blob object? You know the drill by now..
   */
  if (object->type == OBJ_BLOB) {
    if (!revs->blob_objects)
      return NULL;
    if (flags & UNINTERESTING)
      return NULL;
    add_pending_object_with_path(revs, object, name, mode, path);
    return NULL;
  }
  die("%s is unknown object", name);
}

static int everybody_uninteresting(struct commit_list *orig,
           struct commit **interesting_cache)
{
  struct commit_list *list = orig;

  if (*interesting_cache) {
    struct commit *commit = *interesting_cache;
    if (!(commit->object.flags & UNINTERESTING))
      return 0;
  }

  while (list) {
    struct commit *commit = list->item;
    list = list->next;
    if (commit->object.flags & UNINTERESTING)
      continue;

    *interesting_cache = commit;
    return 0;
  }
  return 1;
}

/*
 * A definition of "relevant" commit that we can use to simplify limited graphs
 * by eliminating side branches.
 *
 * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
 * in our list), or that is a specified BOTTOM commit. Then after computing
 * a limited list, during processing we can generally ignore boundary merges
 * coming from outside the graph, (ie from irrelevant parents), and treat
 * those merges as if they were single-parent. TREESAME is defined to consider
 * only relevant parents, if any. If we are TREESAME to our on-graph parents,
 * we don't care if we were !TREESAME to non-graph parents.
 *
 * Treating bottom commits as relevant ensures that a limited graph's
 * connection to the actual bottom commit is not viewed as a side branch, but
 * treated as part of the graph. For example:
 *
 *   ....Z...A---X---o---o---B
 *        .     /
 *         W---Y
 *
 * When computing "A..B", the A-X connection is at least as important as
 * Y-X, despite A being flagged UNINTERESTING.
 *
 * And when computing --ancestry-path "A..B", the A-X connection is more
 * important than Y-X, despite both A and Y being flagged UNINTERESTING.
 */
static inline int relevant_commit(struct commit *commit)
{
  return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
}

/*
 * Return a single relevant commit from a parent list. If we are a TREESAME
 * commit, and this selects one of our parents, then we can safely simplify to
 * that parent.
 */
static struct commit *one_relevant_parent(const struct rev_info *revs,
            struct commit_list *orig)
{
  struct commit_list *list = orig;
  struct commit *relevant = NULL;

  if (!orig)
    return NULL;

  /*
   * For 1-parent commits, or if first-parent-only, then return that
   * first parent (even if not "relevant" by the above definition).
   * TREESAME will have been set purely on that parent.
   */
  if (revs->first_parent_only || !orig->next)
    return orig->item;

  /*
   * For multi-parent commits, identify a sole relevant parent, if any.
   * If we have only one relevant parent, then TREESAME will be set purely
   * with regard to that parent, and we can simplify accordingly.
   *
   * If we have more than one relevant parent, or no relevant parents
   * (and multiple irrelevant ones), then we can't select a parent here
   * and return NULL.
   */
  while (list) {
    struct commit *commit = list->item;
    list = list->next;
    if (relevant_commit(commit)) {
      if (relevant)
        return NULL;
      relevant = commit;
    }
  }
  return relevant;
}

/*
 * The goal is to get REV_TREE_NEW as the result only if the
 * diff consists of all '+' (and no other changes), REV_TREE_OLD
 * if the whole diff is removal of old data, and otherwise
 * REV_TREE_DIFFERENT (of course if the trees are the same we
 * want REV_TREE_SAME).
 *
 * The only time we care about the distinction is when
 * remove_empty_trees is in effect, in which case we care only about
 * whether the whole change is REV_TREE_NEW, or if there's another type
 * of change. Which means we can stop the diff early in either of these
 * cases:
 *
 *   1. We're not using remove_empty_trees at all.
 *
 *   2. We saw anything except REV_TREE_NEW.
 */
#define REV_TREE_SAME   0
#define REV_TREE_NEW    1  /* Only new files */
#define REV_TREE_OLD    2  /* Only files removed */
#define REV_TREE_DIFFERENT  3  /* Mixed changes */
static int tree_difference = REV_TREE_SAME;

static void file_add_remove(struct diff_options *options,
        int addremove,
        unsigned mode UNUSED,
        const struct object_id *oid UNUSED,
        int oid_valid UNUSED,
        const char *fullpath UNUSED,
        unsigned dirty_submodule UNUSED)
{
  int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
  struct rev_info *revs = options->change_fn_data;

  tree_difference |= diff;
  if (!revs->remove_empty_trees || tree_difference != REV_TREE_NEW)
    options->flags.has_changes = 1;
}

static void file_change(struct diff_options *options,
     unsigned old_mode UNUSED,
     unsigned new_mode UNUSED,
     const struct object_id *old_oid UNUSED,
     const struct object_id *new_oid UNUSED,
     int old_oid_valid UNUSED,
     int new_oid_valid UNUSED,
     const char *fullpath UNUSED,
     unsigned old_dirty_submodule UNUSED,
     unsigned new_dirty_submodule UNUSED)
{
  tree_difference = REV_TREE_DIFFERENT;
  options->flags.has_changes = 1;
}

static int bloom_filter_atexit_registered;
static unsigned int count_bloom_filter_maybe;
static unsigned int count_bloom_filter_definitely_not;
static unsigned int count_bloom_filter_false_positive;
static unsigned int count_bloom_filter_not_present;

static void trace2_bloom_filter_statistics_atexit(void)
{
  struct json_writer jw = JSON_WRITER_INIT;

  jw_object_begin(&jw, 0);
  jw_object_intmax(&jw, "filter_not_present", count_bloom_filter_not_present);
  jw_object_intmax(&jw, "maybe", count_bloom_filter_maybe);
  jw_object_intmax(&jw, "definitely_not", count_bloom_filter_definitely_not);
  jw_object_intmax(&jw, "false_positive", count_bloom_filter_false_positive);
  jw_end(&jw);

  trace2_data_json("bloom", the_repository, "statistics", &jw);

  jw_release(&jw);
}

static int forbid_bloom_filters(struct pathspec *spec)
{
  unsigned int allowed_magic =
    PATHSPEC_FROMTOP |
    PATHSPEC_MAXDEPTH |
    PATHSPEC_LITERAL |
    PATHSPEC_GLOB |
    PATHSPEC_ATTR;

  if (spec->magic & ~allowed_magic)
    return 1;
  for (size_t nr = 0; nr < spec->nr; nr++)
    if (spec->items[nr].magic & ~allowed_magic)
      return 1;

  return 0;
}

static void release_revisions_bloom_keyvecs(struct rev_info *revs);

static int convert_pathspec_to_bloom_keyvec(struct bloom_keyvec **out,
              const struct pathspec_item *pi,
              const struct bloom_filter_settings *settings)
{
  char *path_alloc = NULL;
  const char *path;
  size_t len;
  int res = -1;

  len = pi->nowildcard_len;
  if (len != pi->len) {
    /*
     * for path like "dir/file*", nowildcard part would be
     * "dir/file", but only "dir" should be used for the
     * bloom filter.
     */
    while (len > 0 && pi->match[len - 1] != '/')
      len--;
  }
  /* remove single trailing slash from path, if needed */
  if (len > 0 && pi->match[len - 1] == '/')
    len--;

  if (!len)
    goto cleanup;

  if (len != pi->len) {
    path_alloc = xmemdupz(pi->match, len);
    path = path_alloc;
  } else
    path = pi->match;

  *out = bloom_keyvec_new(path, len, settings);

  res = 0;
cleanup:
  free(path_alloc);
  return res;
}

static void prepare_to_use_bloom_filter(struct rev_info *revs)
{
  if (!revs->commits)
    return;

  if (forbid_bloom_filters(&revs->prune_data))
    return;

  repo_parse_commit(revs->repo, revs->commits->item);

  revs->bloom_filter_settings = get_bloom_filter_settings(revs->repo);
  if (!revs->bloom_filter_settings)
    return;

  if (!revs->pruning.pathspec.nr)
    return;

  revs->bloom_keyvecs_nr = revs->pruning.pathspec.nr;
  CALLOC_ARRAY(revs->bloom_keyvecs, revs->bloom_keyvecs_nr);

  for (int i = 0; i < revs->pruning.pathspec.nr; i++) {
    if (convert_pathspec_to_bloom_keyvec(&revs->bloom_keyvecs[i],
                 &revs->pruning.pathspec.items[i],
                 revs->bloom_filter_settings))
      goto fail;
  }

  if (trace2_is_enabled() && !bloom_filter_atexit_registered) {
    atexit(trace2_bloom_filter_statistics_atexit);
    bloom_filter_atexit_registered = 1;
  }

  return;

fail:
  revs->bloom_filter_settings = NULL;
  release_revisions_bloom_keyvecs(revs);
}

static int check_maybe_different_in_bloom_filter(struct rev_info *revs,
             struct commit *commit)
{
  struct bloom_filter *filter;
  int result = 0;

  if (commit_graph_generation(commit) == GENERATION_NUMBER_INFINITY)
    return -1;

  filter = get_bloom_filter(revs->repo, commit);

  if (!filter) {
    count_bloom_filter_not_present++;
    return -1;
  }

  for (size_t nr = 0; !result && nr < revs->bloom_keyvecs_nr; nr++) {
    result = bloom_filter_contains_vec(filter,
               revs->bloom_keyvecs[nr],
               revs->bloom_filter_settings);
  }

  if (result)
    count_bloom_filter_maybe++;
  else
    count_bloom_filter_definitely_not++;

  return result;
}

static int rev_compare_tree(struct rev_info *revs,
          struct commit *parent, struct commit *commit, int nth_parent)
{
  struct tree *t1 = repo_get_commit_tree(the_repository, parent);
  struct tree *t2 = repo_get_commit_tree(the_repository, commit);
  int bloom_ret = 1;

  if (!t1)
    return REV_TREE_NEW;
  if (!t2)
    return REV_TREE_OLD;

  if (revs->simplify_by_decoration) {
    /*
     * If we are simplifying by decoration, then the commit
     * is worth showing if it has a tag pointing at it.
     */
    if (get_name_decoration(&commit->object))
      return REV_TREE_DIFFERENT;
    /*
     * A commit that is not pointed by a tag is uninteresting
     * if we are not limited by path.  This means that you will
     * see the usual "commits that touch the paths" plus any
     * tagged commit by specifying both --simplify-by-decoration
     * and pathspec.
     */
    if (!revs->prune_data.nr)
      return REV_TREE_SAME;
  }

  if (revs->bloom_keyvecs_nr && !nth_parent) {
    bloom_ret = check_maybe_different_in_bloom_filter(revs, commit);

    if (bloom_ret == 0)
      return REV_TREE_SAME;
  }

  tree_difference = REV_TREE_SAME;
  revs->pruning.flags.has_changes = 0;
  diff_tree_oid(&t1->object.oid, &t2->object.oid, "", &revs->pruning);

  if (!nth_parent)
    if (bloom_ret == 1 && tree_difference == REV_TREE_SAME)
      count_bloom_filter_false_positive++;

  return tree_difference;
}

static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit,
          int nth_parent)
{
  struct tree *t1 = repo_get_commit_tree(the_repository, commit);
  int bloom_ret = -1;

  if (!t1)
    return 0;

  if (!nth_parent && revs->bloom_keyvecs_nr) {
    bloom_ret = check_maybe_different_in_bloom_filter(revs, commit);
    if (!bloom_ret)
      return 1;
  }

  tree_difference = REV_TREE_SAME;
  revs->pruning.flags.has_changes = 0;
  diff_tree_oid(NULL, &t1->object.oid, "", &revs->pruning);

  if (bloom_ret == 1 && tree_difference == REV_TREE_SAME)
    count_bloom_filter_false_positive++;

  return tree_difference == REV_TREE_SAME;
}

struct treesame_state {
  unsigned int nparents;
  unsigned char treesame[FLEX_ARRAY];
};

static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
{
  unsigned n = commit_list_count(commit->parents);
  struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
  st->nparents = n;
  add_decoration(&revs->treesame, &commit->object, st);
  return st;
}

/*
 * Must be called immediately after removing the nth_parent from a commit's
 * parent list, if we are maintaining the per-parent treesame[] decoration.
 * This does not recalculate the master TREESAME flag - update_treesame()
 * should be called to update it after a sequence of treesame[] modifications
 * that may have affected it.
 */
static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
{
  struct treesame_state *st;
  int old_same;

  if (!commit->parents) {
    /*
     * Have just removed the only parent from a non-merge.
     * Different handling, as we lack decoration.
     */
    if (nth_parent != 0)
      die("compact_treesame %u", nth_parent);
    old_same = !!(commit->object.flags & TREESAME);
    if (rev_same_tree_as_empty(revs, commit, nth_parent))
      commit->object.flags |= TREESAME;
    else
      commit->object.flags &= ~TREESAME;
    return old_same;
  }

  st = lookup_decoration(&revs->treesame, &commit->object);
  if (!st || nth_parent >= st->nparents)
    die("compact_treesame %u", nth_parent);

  old_same = st->treesame[nth_parent];
  memmove(st->treesame + nth_parent,
    st->treesame + nth_parent + 1,
    st->nparents - nth_parent - 1);

  /*
   * If we've just become a non-merge commit, update TREESAME
   * immediately, and remove the no-longer-needed decoration.
   * If still a merge, defer update until update_treesame().
   */
  if (--st->nparents == 1) {
    if (commit->parents->next)
      die("compact_treesame parents mismatch");
    if (st->treesame[0] && revs->dense)
      commit->object.flags |= TREESAME;
    else
      commit->object.flags &= ~TREESAME;
    free(add_decoration(&revs->treesame, &commit->object, NULL));
  }

  return old_same;
}

static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
{
  if (commit->parents && commit->parents->next) {
    unsigned n;
    struct treesame_state *st;
    struct commit_list *p;
    unsigned relevant_parents;
    unsigned relevant_change, irrelevant_change;

    st = lookup_decoration(&revs->treesame, &commit->object);
    if (!st)
      die("update_treesame %s", oid_to_hex(&commit->object.oid));
    relevant_parents = 0;
    relevant_change = irrelevant_change = 0;
    for (p = commit->parents, n = 0; p; n++, p = p->next) {
      if (relevant_commit(p->item)) {
        relevant_change |= !st->treesame[n];
        relevant_parents++;
      } else
        irrelevant_change |= !st->treesame[n];
    }
    if (relevant_parents ? relevant_change : irrelevant_change)
      commit->object.flags &= ~TREESAME;
    else
      commit->object.flags |= TREESAME;
  }

  return commit->object.flags & TREESAME;
}

static inline int limiting_can_increase_treesame(const struct rev_info *revs)
{
  /*
   * TREESAME is irrelevant unless prune && dense;
   * if simplify_history is set, we can't have a mixture of TREESAME and
   *    !TREESAME INTERESTING parents (and we don't have treesame[]
   *    decoration anyway);
   * if first_parent_only is set, then the TREESAME flag is locked
   *    against the first parent (and again we lack treesame[] decoration).
   */
  return revs->prune && revs->dense &&
         !revs->simplify_history &&
         !revs->first_parent_only;
}

static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
{
  struct commit_list **pp, *parent;
  struct treesame_state *ts = NULL;
  int relevant_change = 0, irrelevant_change = 0;
  int relevant_parents, nth_parent;

  /*
   * If we don't do pruning, everything is interesting
   */
  if (!revs->prune)
    return;

  if (!repo_get_commit_tree(the_repository, commit))
    return;

  if (!commit->parents) {
    /*
     * Pretend as if we are comparing ourselves to the
     * (non-existent) first parent of this commit object. Even
     * though no such parent exists, its changed-path Bloom filter
     * (if one exists) is relative to the empty tree, using Bloom
     * filters is allowed here.
     */
    if (rev_same_tree_as_empty(revs, commit, 0))
      commit->object.flags |= TREESAME;
    return;
  }

  /*
   * Normal non-merge commit? If we don't want to make the
   * history dense, we consider it always to be a change..
   */
  if (!revs->dense && !commit->parents->next)
    return;

  for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
       (parent = *pp) != NULL;
       pp = &parent->next, nth_parent++) {
    struct commit *p = parent->item;
    if (relevant_commit(p))
      relevant_parents++;

    if (nth_parent == 1) {
      /*
       * This our second loop iteration - so we now know
       * we're dealing with a merge.
       *
       * Do not compare with later parents when we care only about
       * the first parent chain, in order to avoid derailing the
       * traversal to follow a side branch that brought everything
       * in the path we are limited to by the pathspec.
       */
      if (revs->first_parent_only)
        break;
      /*
       * If this will remain a potentially-simplifiable
       * merge, remember per-parent treesame if needed.
       * Initialise the array with the comparison from our
       * first iteration.
       */
      if (revs->treesame.name &&
          !revs->simplify_history &&
          !(commit->object.flags & UNINTERESTING)) {
        ts = initialise_treesame(revs, commit);
        if (!(irrelevant_change || relevant_change))
          ts->treesame[0] = 1;
      }
    }
    if (repo_parse_commit(revs->repo, p) < 0)
      die("cannot simplify commit %s (because of %s)",
          oid_to_hex(&commit->object.oid),
          oid_to_hex(&p->object.oid));
    switch (rev_compare_tree(revs, p, commit, nth_parent)) {
    case REV_TREE_SAME:
      if (!revs->simplify_history || !relevant_commit(p)) {
        /* Even if a merge with an uninteresting
         * side branch brought the entire change
         * we are interested in, we do not want
         * to lose the other branches of this
         * merge, so we just keep going.
         */
        if (ts)
          ts->treesame[nth_parent] = 1;
        continue;
      }

      free_commit_list(parent->next);
      parent->next = NULL;
      while (commit->parents != parent)
        pop_commit(&commit->parents);
      commit->parents = parent;

      /*
       * A merge commit is a "diversion" if it is not
       * TREESAME to its first parent but is TREESAME
       * to a later parent. In the simplified history,
       * we "divert" the history walk to the later
       * parent. These commits are shown when "show_pulls"
       * is enabled, so do not mark the object as
       * TREESAME here.
       */
      if (!revs->show_pulls || !nth_parent)
        commit->object.flags |= TREESAME;

      return;

    case REV_TREE_NEW:
      if (revs->remove_empty_trees &&
          rev_same_tree_as_empty(revs, p, nth_parent)) {
        /* We are adding all the specified
         * paths from this parent, so the
         * history beyond this parent is not
         * interesting.  Remove its parents
         * (they are grandparents for us).
         * IOW, we pretend this parent is a
         * "root" commit.
         */
        if (repo_parse_commit(revs->repo, p) < 0)
          die("cannot simplify commit %s (invalid %s)",
              oid_to_hex(&commit->object.oid),
              oid_to_hex(&p->object.oid));
        free_commit_list(p->parents);
        p->parents = NULL;
      }
    /* fallthrough */
    case REV_TREE_OLD:
    case REV_TREE_DIFFERENT:
      if (relevant_commit(p))
        relevant_change = 1;
      else
        irrelevant_change = 1;

      if (!nth_parent)
        commit->object.flags |= PULL_MERGE;

      continue;
    }
    die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
  }

  /*
   * TREESAME is straightforward for single-parent commits. For merge
   * commits, it is most useful to define it so that "irrelevant"
   * parents cannot make us !TREESAME - if we have any relevant
   * parents, then we only consider TREESAMEness with respect to them,
   * allowing irrelevant merges from uninteresting branches to be
   * simplified away. Only if we have only irrelevant parents do we
   * base TREESAME on them. Note that this logic is replicated in
   * update_treesame, which should be kept in sync.
   */
  if (relevant_parents ? !relevant_change : !irrelevant_change)
    commit->object.flags |= TREESAME;
}

static int process_parents(struct rev_info *revs, struct commit *commit,
         struct commit_list **list, struct prio_queue *queue)
{
  struct commit_list *parent = commit->parents;
  unsigned pass_flags;

  if (commit->object.flags & ADDED)
    return 0;
  if (revs->do_not_die_on_missing_objects &&
      oidset_contains(&revs->missing_commits, &commit->object.oid))
    return 0;
  commit->object.flags |= ADDED;

  if (revs->include_check &&
      !revs->include_check(commit, revs->include_check_data))
    return 0;

  /*
   * If the commit is uninteresting, don't try to
   * prune parents - we want the maximal uninteresting
   * set.
   *
   * Normally we haven't parsed the parent
   * yet, so we won't have a parent of a parent
   * here. However, it may turn out that we've
   * reached this commit some other way (where it
   * wasn't uninteresting), in which case we need
   * to mark its parents recursively too..
   */
  if (commit->object.flags & UNINTERESTING) {
    while (parent) {
      struct commit *p = parent->item;
      parent = parent->next;
      if (p)
        p->object.flags |= UNINTERESTING;
      if (repo_parse_commit_gently(revs->repo, p, 1) < 0)
        continue;
      if (p->parents)
        mark_parents_uninteresting(revs, p);
      if (p->object.flags & SEEN)
        continue;
      p->object.flags |= (SEEN | NOT_USER_GIVEN);
      if (list)
        commit_list_insert_by_date(p, list);
      if (queue)
        prio_queue_put(queue, p);
      if (revs->exclude_first_parent_only)
        break;
    }
    return 0;
  }

  /*
   * Ok, the commit wasn't uninteresting. Try to
   * simplify the commit history and find the parent
   * that has no differences in the path set if one exists.
   */
  try_to_simplify_commit(revs, commit);

  if (revs->no_walk)
    return 0;

  pass_flags = (commit->object.flags & (SYMMETRIC_LEFT | ANCESTRY_PATH));

  for (parent = commit->parents; parent; parent = parent->next) {
    struct commit *p = parent->item;
    int gently = revs->ignore_missing_links ||
           revs->exclude_promisor_objects ||
           revs->do_not_die_on_missing_objects;
    if (repo_parse_commit_gently(revs->repo, p, gently) < 0) {
      if (revs->exclude_promisor_objects &&
          is_promisor_object(revs->repo, &p->object.oid)) {
        if (revs->first_parent_only)
          break;
        continue;
      }

      if (revs->do_not_die_on_missing_objects)
        oidset_insert(&revs->missing_commits, &p->object.oid);
      else
        return -1; /* corrupt repository */
    }
    if (revs->sources) {
      char **slot = revision_sources_at(revs->sources, p);

      if (!*slot)
        *slot = *revision_sources_at(revs->sources, commit);
    }
    p->object.flags |= pass_flags;
    if (!(p->object.flags & SEEN)) {
      p->object.flags |= (SEEN | NOT_USER_GIVEN);
      if (list)
        commit_list_insert_by_date(p, list);
      if (queue)
        prio_queue_put(queue, p);
    }
    if (revs->first_parent_only)
      break;
  }
  return 0;
}

static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
{
  struct commit_list *p;
  int left_count = 0, right_count = 0;
  int left_first;
  struct patch_ids ids;
  unsigned cherry_flag;

  /* First count the commits on the left and on the right */
  for (p = list; p; p = p->next) {
    struct commit *commit = p->item;
    unsigned flags = commit->object.flags;
    if (flags & BOUNDARY)
      ;
    else if (flags & SYMMETRIC_LEFT)
      left_count++;
    else
      right_count++;
  }

  if (!left_count || !right_count)
    return;

  left_first = left_count < right_count;
  init_patch_ids(revs->repo, &ids);
  ids.diffopts.pathspec = revs->diffopt.pathspec;

  /* Compute patch-ids for one side */
  for (p = list; p; p = p->next) {
    struct commit *commit = p->item;
    unsigned flags = commit->object.flags;

    if (flags & BOUNDARY)
      continue;
    /*
     * If we have fewer left, left_first is set and we omit
     * commits on the right branch in this loop.  If we have
     * fewer right, we skip the left ones.
     */
    if (left_first != !!(flags & SYMMETRIC_LEFT))
      continue;
    add_commit_patch_id(commit, &ids);
  }

  /* either cherry_mark or cherry_pick are true */
  cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;

  /* Check the other side */
  for (p = list; p; p = p->next) {
    struct commit *commit = p->item;
    struct patch_id *id;
    unsigned flags = commit->object.flags;

    if (flags & BOUNDARY)
      continue;
    /*
     * If we have fewer left, left_first is set and we omit
     * commits on the left branch in this loop.
     */
    if (left_first == !!(flags & SYMMETRIC_LEFT))
      continue;

    /*
     * Have we seen the same patch id?
     */
    id = patch_id_iter_first(commit, &ids);
    if (!id)
      continue;

    commit->object.flags |= cherry_flag;
    do {
      id->commit->object.flags |= cherry_flag;
    } while ((id = patch_id_iter_next(id, &ids)));
  }

  free_patch_ids(&ids);
}

/* How many extra uninteresting commits we want to see.. */
#define SLOP 5

static int still_interesting(struct commit_list *src, timestamp_t date, int slop,
           struct commit **interesting_cache)
{
  /*
   * No source list at all? We're definitely done..
   */
  if (!src)
    return 0;

  /*
   * Does the destination list contain entries with a date
   * before the source list? Definitely _not_ done.
   */
  if (date <= src->item->date)
    return SLOP;

  /*
   * Does the source list still have interesting commits in
   * it? Definitely not done..
   */
  if (!everybody_uninteresting(src, interesting_cache))
    return SLOP;

  /* Ok, we're closing in.. */
  return slop-1;
}

/*
 * "rev-list --ancestry-path=C_0 [--ancestry-path=C_1 ...] A..B"
 * computes commits that are ancestors of B but not ancestors of A but
 * further limits the result to those that have any of C in their
 * ancestry path (i.e. are either ancestors of any of C, descendants
 * of any of C, or are any of C). If --ancestry-path is specified with
 * no commit, we use all bottom commits for C.
 *
 * Before this function is called, ancestors of C will have already
 * been marked with ANCESTRY_PATH previously.
 *
 * This takes the list of bottom commits and the result of "A..B"
 * without --ancestry-path, and limits the latter further to the ones
 * that have any of C in their ancestry path. Since the ancestors of C
 * have already been marked (a prerequisite of this function), we just
 * need to mark the descendants, then exclude any commit that does not
 * have any of these marks.
 */
static void limit_to_ancestry(struct commit_list *bottoms, struct commit_list *list)
{
  struct commit_list *p;
  struct commit_list *rlist = NULL;
  int made_progress;

  /*
   * Reverse the list so that it will be likely that we would
   * process parents before children.
   */
  for (p = list; p; p = p->next)
    commit_list_insert(p->item, &rlist);

  for (p = bottoms; p; p = p->next)
    p->item->object.flags |= TMP_MARK;

  /*
   * Mark the ones that can reach bottom commits in "list",
   * in a bottom-up fashion.
   */
  do {
    made_progress = 0;
    for (p = rlist; p; p = p->next) {
      struct commit *c = p->item;
      struct commit_list *parents;
      if (c->object.flags & (TMP_MARK | UNINTERESTING))
        continue;
      for (parents = c->parents;
           parents;
           parents = parents->next) {
        if (!(parents->item->object.flags & TMP_MARK))
          continue;
        c->object.flags |= TMP_MARK;
        made_progress = 1;
        break;
      }
    }
  } while (made_progress);

  /*
   * NEEDSWORK: decide if we want to remove parents that are
   * not marked with TMP_MARK from commit->parents for commits
   * in the resulting list.  We may not want to do that, though.
   */

  /*
   * The ones that are not marked with either TMP_MARK or
   * ANCESTRY_PATH are uninteresting
   */
  for (p = list; p; p = p->next) {
    struct commit *c = p->item;
    if (c->object.flags & (TMP_MARK | ANCESTRY_PATH))
      continue;
    c->object.flags |= UNINTERESTING;
  }

  /* We are done with TMP_MARK and ANCESTRY_PATH */
  for (p = list; p; p = p->next)
    p->item->object.flags &= ~(TMP_MARK | ANCESTRY_PATH);
  for (p = bottoms; p; p = p->next)
    p->item->object.flags &= ~(TMP_MARK | ANCESTRY_PATH);
  free_commit_list(rlist);
}

/*
 * Before walking the history, add the set of "negative" refs the
 * caller has asked to exclude to the bottom list.
 *
 * This is used to compute "rev-list --ancestry-path A..B", as we need
 * to filter the result of "A..B" further to the ones that can actually
 * reach A.
 */
static void collect_bottom_commits(struct commit_list *list,
           struct commit_list **bottom)
{
  struct commit_list *elem;
  for (elem = list; elem; elem = elem->next)
    if (elem->item->object.flags & BOTTOM)
      commit_list_insert(elem->item, bottom);
}

/* Assumes either left_only or right_only is set */
static void limit_left_right(struct commit_list *list, struct rev_info *revs)
{
  struct commit_list *p;

  for (p = list; p; p = p->next) {
    struct commit *commit = p->item;

    if (revs->right_only) {
      if (commit->object.flags & SYMMETRIC_LEFT)
        commit->object.flags |= SHOWN;
    } else  /* revs->left_only is set */
      if (!(commit->object.flags & SYMMETRIC_LEFT))
        commit->object.flags |= SHOWN;
  }
}

static int limit_list(struct rev_info *revs)
{
  int slop = SLOP;
  timestamp_t date = TIME_MAX;
  struct commit_list *original_list = revs->commits;
  struct commit_list *newlist = NULL;
  struct commit_list **p = &newlist;
  struct commit *interesting_cache = NULL;

  if (revs->ancestry_path_implicit_bottoms) {
    collect_bottom_commits(original_list,
               &revs->ancestry_path_bottoms);
    if (!revs->ancestry_path_bottoms)
      die("--ancestry-path given but there are no bottom commits");
  }

  while (original_list) {
    struct commit *commit = pop_commit(&original_list);
    struct object *obj = &commit->object;

    if (commit == interesting_cache)
      interesting_cache = NULL;

    if (revs->max_age != -1 && (commit->date < revs->max_age))
      obj->flags |= UNINTERESTING;
    if (process_parents(revs, commit, &original_list, NULL) < 0)
      return -1;
    if (obj->flags & UNINTERESTING) {
      mark_parents_uninteresting(revs, commit);
      slop = still_interesting(original_list, date, slop, &interesting_cache);
      if (slop)
        continue;
      break;
    }
    if (revs->min_age != -1 && (commit->date > revs->min_age) &&
        !revs->line_level_traverse)
      continue;
    if (revs->max_age_as_filter != -1 &&
      (commit->date < revs->max_age_as_filter) && !revs->line_level_traverse)
      continue;
    date = commit->date;
    p = &commit_list_insert(commit, p)->next;
  }
  if (revs->cherry_pick || revs->cherry_mark)
    cherry_pick_list(newlist, revs);

  if (revs->left_only || revs->right_only)
    limit_left_right(newlist, revs);

  if (revs->ancestry_path)
    limit_to_ancestry(revs->ancestry_path_bottoms, newlist);

  /*
   * Check if any commits have become TREESAME by some of their parents
   * becoming UNINTERESTING.
   */
  if (limiting_can_increase_treesame(revs)) {
    struct commit_list *list = NULL;
    for (list = newlist; list; list = list->next) {
      struct commit *c = list->item;
      if (c->object.flags & (UNINTERESTING | TREESAME))
        continue;
      update_treesame(revs, c);
    }
  }

  free_commit_list(original_list);
  revs->commits = newlist;
  return 0;
}

/*
 * Add an entry to refs->cmdline with the specified information.
 * *name is copied.
 */
static void add_rev_cmdline(struct rev_info *revs,
          struct object *item,
          const char *name,
          int whence,
          unsigned flags)
{
  struct rev_cmdline_info *info = &revs->cmdline;
  unsigned int nr = info->nr;

  ALLOC_GROW(info->rev, nr + 1, info->alloc);
  info->rev[nr].item = item;
  info->rev[nr].name = xstrdup(name);
  info->rev[nr].whence = whence;
  info->rev[nr].flags = flags;
  info->nr++;
}

static void add_rev_cmdline_list(struct rev_info *revs,
         struct commit_list *commit_list,
         int whence,
         unsigned flags)
{
  while (commit_list) {
    struct object *object = &commit_list->item->object;
    add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
        whence, flags);
    commit_list = commit_list->next;
  }
}

int ref_excluded(const struct ref_exclusions *exclusions, const char *path)
{
  const char *stripped_path = strip_namespace(path);
  struct string_list_item *item;

  for_each_string_list_item(item, &exclusions->excluded_refs) {
    if (!wildmatch(item->string, path, 0))
      return 1;
  }

  if (ref_is_hidden(stripped_path, path, &exclusions->hidden_refs))
    return 1;

  return 0;
}

void init_ref_exclusions(struct ref_exclusions *exclusions)
{
  struct ref_exclusions blank = REF_EXCLUSIONS_INIT;
  memcpy(exclusions, &blank, sizeof(*exclusions));
}

void clear_ref_exclusions(struct ref_exclusions *exclusions)
{
  string_list_clear(&exclusions->excluded_refs, 0);
  strvec_clear(&exclusions->hidden_refs);
  exclusions->hidden_refs_configured = 0;
}

void add_ref_exclusion(struct ref_exclusions *exclusions, const char *exclude)
{
  string_list_append(&exclusions->excluded_refs, exclude);
}

struct exclude_hidden_refs_cb {
  struct ref_exclusions *exclusions;
  const char *section;
};

static int hide_refs_config(const char *var, const char *value,
          const struct config_context *ctx UNUSED,
          void *cb_data)
{
  struct exclude_hidden_refs_cb *cb = cb_data;
  cb->exclusions->hidden_refs_configured = 1;
  return parse_hide_refs_config(var, value, cb->section,
              &cb->exclusions->hidden_refs);
}

void exclude_hidden_refs(struct ref_exclusions *exclusions, const char *section)
{
  struct exclude_hidden_refs_cb cb;

  if (strcmp(section, "fetch") && strcmp(section, "receive") &&
      strcmp(section, "uploadpack"))
    die(_("unsupported section for hidden refs: %s"), section);

  if (exclusions->hidden_refs_configured)
    die(_("--exclude-hidden= passed more than once"));

  cb.exclusions = exclusions;
  cb.section = section;

  repo_config(the_repository, hide_refs_config, &cb);
}

struct all_refs_cb {
  int all_flags;
  int warned_bad_reflog;
  struct rev_info *all_revs;
  const char *name_for_errormsg;
  struct worktree *wt;
};

static int handle_one_ref(const struct reference *ref, void *cb_data)
{
  struct all_refs_cb *cb = cb_data;
  struct object *object;

  if (ref_excluded(&cb->all_revs->ref_excludes, ref->name))
      return 0;

  object = get_reference(cb->all_revs, ref->name, ref->oid, cb->all_flags);
  add_rev_cmdline(cb->all_revs, object, ref->name, REV_CMD_REF, cb->all_flags);
  add_pending_object(cb->all_revs, object, ref->name);
  return 0;
}

static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
  unsigned flags)
{
  cb->all_revs = revs;
  cb->all_flags = flags;
  revs->rev_input_given = 1;
  cb->wt = NULL;
}

static void handle_refs(struct ref_store *refs,
      struct rev_info *revs, unsigned flags,
      int (*for_each)(struct ref_store *, each_ref_fn, void *))
{
  struct all_refs_cb cb;

  if (!refs) {
    /* this could happen with uninitialized submodules */
    return;
  }

  init_all_refs_cb(&cb, revs, flags);
  for_each(refs, handle_one_ref, &cb);
}

static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
{
  struct all_refs_cb *cb = cb_data;
  if (!is_null_oid(oid)) {
    struct object *o = parse_object(cb->all_revs->repo, oid);
    if (o) {
      o->flags |= cb->all_flags;
      /* ??? CMDLINEFLAGS ??? */
      add_pending_object(cb->all_revs, o, "");
    }
    else if (!cb->warned_bad_reflog) {
      warning("reflog of '%s' references pruned commits",
        cb->name_for_errormsg);
      cb->warned_bad_reflog = 1;
    }
  }
}

static int handle_one_reflog_ent(const char *refname UNUSED,
         struct object_id *ooid, struct object_id *noid,
         const char *email UNUSED,
         timestamp_t timestamp UNUSED,
         int tz UNUSED,
         const char *message UNUSED,
         void *cb_data)
{
  handle_one_reflog_commit(ooid, cb_data);
  handle_one_reflog_commit(noid, cb_data);
  return 0;
}

static int handle_one_reflog(const char *refname_in_wt, void *cb_data)
{
  struct all_refs_cb *cb = cb_data;
  struct strbuf refname = STRBUF_INIT;

  cb->warned_bad_reflog = 0;
  strbuf_worktree_ref(cb->wt, &refname, refname_in_wt);
  cb->name_for_errormsg = refname.buf;
  refs_for_each_reflog_ent(get_main_ref_store(the_repository),
         refname.buf,
         handle_one_reflog_ent, cb_data);
  strbuf_release(&refname);
  return 0;
}

static void add_other_reflogs_to_pending(struct all_refs_cb *cb)
{
  struct worktree **worktrees, **p;

  worktrees = get_worktrees();
  for (p = worktrees; *p; p++) {
    struct worktree *wt = *p;

    if (wt->is_current)
      continue;

    cb->wt = wt;
    refs_for_each_reflog(get_worktree_ref_store(wt),
             handle_one_reflog,
             cb);
  }
  free_worktrees(worktrees);
}

void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
{
  struct all_refs_cb cb;

  cb.all_revs = revs;
  cb.all_flags = flags;
  cb.wt = NULL;
  refs_for_each_reflog(get_main_ref_store(the_repository),
           handle_one_reflog, &cb);

  if (!revs->single_worktree)
    add_other_reflogs_to_pending(&cb);
}

static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
         struct strbuf *path, unsigned int flags)
{
  size_t baselen = path->len;
  int i;

  if (it->entry_count >= 0) {
    struct tree *tree = lookup_tree(revs->repo, &it->oid);
    tree->object.flags |= flags;
    add_pending_object_with_path(revs, &tree->object, "",
               040000, path->buf);
  }

  for (i = 0; i < it->subtree_nr; i++) {
    struct cache_tree_sub *sub = it->down[i];
    strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
    add_cache_tree(sub->cache_tree, revs, path, flags);
    strbuf_setlen(path, baselen);
  }

}

static void add_resolve_undo_to_pending(struct index_state *istate, struct rev_info *revs)
{
  struct string_list_item *item;
  struct string_list *resolve_undo = istate->resolve_undo;

  if (!resolve_undo)
    return;

  for_each_string_list_item(item, resolve_undo) {
    const char *path = item->string;
    struct resolve_undo_info *ru = item->util;
    int i;

    if (!ru)
      continue;
    for (i = 0; i < 3; i++) {
      struct blob *blob;

      if (!ru->mode[i] || !S_ISREG(ru->mode[i]))
        continue;

      blob = lookup_blob(revs->repo, &ru->oid[i]);
      if (!blob) {
        warning(_("resolve-undo records `%s` which is missing"),
          oid_to_hex(&ru->oid[i]));
        continue;
      }
      add_pending_object_with_path(revs, &blob->object, "",
                 ru->mode[i], path);
    }
  }
}

static void do_add_index_objects_to_pending(struct rev_info *revs,
              struct index_state *istate,
              unsigned int flags)
{
  int i;

  /* TODO: audit for interaction with sparse-index. */
  ensure_full_index(istate);
  for (i = 0; i < istate->cache_nr; i++) {
    struct cache_entry *ce = istate->cache[i];
    struct blob *blob;

    if (S_ISGITLINK(ce->ce_mode))
      continue;

    blob = lookup_blob(revs->repo, &ce->oid);
    if (!blob)
      die("unable to add index blob to traversal");
    blob->object.flags |= flags;
    add_pending_object_with_path(revs, &blob->object, "",
               ce->ce_mode, ce->name);
  }

  if (istate->cache_tree) {
    struct strbuf path = STRBUF_INIT;
    add_cache_tree(istate->cache_tree, revs, &path, flags);
    strbuf_release(&path);
  }

  add_resolve_undo_to_pending(istate, revs);
}

void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
{
  struct worktree **worktrees, **p;

  repo_read_index(revs->repo);
  do_add_index_objects_to_pending(revs, revs->repo->index, flags);

  if (revs->single_worktree)
    return;

  worktrees = get_worktrees();
  for (p = worktrees; *p; p++) {
    struct worktree *wt = *p;
    struct index_state istate = INDEX_STATE_INIT(revs->repo);
    char *wt_gitdir;

    if (wt->is_current)
      continue; /* current index already taken care of */

    wt_gitdir = get_worktree_git_dir(wt);

    if (read_index_from(&istate,
            worktree_git_path(the_repository, wt, "index"),
            wt_gitdir) > 0)
      do_add_index_objects_to_pending(revs, &istate, flags);

    discard_index(&istate);
    free(wt_gitdir);
  }
  free_worktrees(worktrees);
}

struct add_alternate_refs_data {
  struct rev_info *revs;
  unsigned int flags;
};

static void add_one_alternate_ref(const struct object_id *oid,
          void *vdata)
{
  const char *name = ".alternate";
  struct add_alternate_refs_data *data = vdata;
  struct object *obj;

  obj = get_reference(data->revs, name, oid, data->flags);
  add_rev_cmdline(data->revs, obj, name, REV_CMD_REV, data->flags);
  add_pending_object(data->revs, obj, name);
}

static void add_alternate_refs_to_pending(struct rev_info *revs,
            unsigned int flags)
{
  struct add_alternate_refs_data data;
  data.revs = revs;
  data.flags = flags;
  odb_for_each_alternate_ref(the_repository->objects,
           add_one_alternate_ref, &data);
}

static int add_parents_only(struct rev_info *revs, const char *arg_, int flags,
          int exclude_parent)
{
  struct object_id oid;
  struct object *it;
  struct commit *commit;
  struct commit_list *parents;
  int parent_number;
  const char *arg = arg_;

  if (*arg == '^') {
    flags ^= UNINTERESTING | BOTTOM;
    arg++;
  }
  if (repo_get_oid_committish(the_repository, arg, &oid))
    return 0;
  while (1) {
    it = get_reference(revs, arg, &oid, 0);
    if (!it && revs->ignore_missing)
      return 0;
    if (it->type != OBJ_TAG)
      break;
    if (!((struct tag*)it)->tagged)
      return 0;
    oidcpy(&oid, &((struct tag*)it)->tagged->oid);
  }
  if (it->type != OBJ_COMMIT)
    return 0;
  commit = (struct commit *)it;
  if (exclude_parent &&
      exclude_parent > commit_list_count(commit->parents))
    return 0;
  for (parents = commit->parents, parent_number = 1;
       parents;
       parents = parents->next, parent_number++) {
    if (exclude_parent && parent_number != exclude_parent)
      continue;

    it = &parents->item->object;
    it->flags |= flags;
    add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
    add_pending_object(revs, it, arg);
  }
  return 1;
}

void repo_init_revisions(struct repository *r,
       struct rev_info *revs,
       const char *prefix)
{
  struct rev_info blank = REV_INFO_INIT;
  memcpy(revs, &blank, sizeof(*revs));

  revs->repo = r;
  revs->pruning.repo = r;
  revs->pruning.add_remove = file_add_remove;
  revs->pruning.change = file_change;
  revs->pruning.change_fn_data = revs;
  revs->prefix = prefix;

  grep_init(&revs->grep_filter, revs->repo);
  revs->grep_filter.status_only = 1;

  repo_diff_setup(revs->repo, &revs->diffopt);
  if (prefix && !revs->diffopt.prefix) {
    revs->diffopt.prefix = prefix;
    revs->diffopt.prefix_length = strlen(prefix);
  }

  init_display_notes(&revs->notes_opt);
  list_objects_filter_init(&revs->filter);
  init_ref_exclusions(&revs->ref_excludes);
  oidset_init(&revs->missing_commits, 0);
}

static void add_pending_commit_list(struct rev_info *revs,
            struct commit_list *commit_list,
            unsigned int flags)
{
  while (commit_list) {
    struct object *object = &commit_list->item->object;
    object->flags |= flags;
    add_pending_object(revs, object, oid_to_hex(&object->oid));
    commit_list = commit_list->next;
  }
}

static const char *lookup_other_head(struct object_id *oid)
{
  int i;
  static const char *const other_head[] = {
    "MERGE_HEAD", "CHERRY_PICK_HEAD", "REVERT_HEAD", "REBASE_HEAD"
  };

  for (i = 0; i < ARRAY_SIZE(other_head); i++)
    if (!refs_read_ref_full(get_main_ref_store(the_repository), other_head[i],
          RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
          oid, NULL)) {
      if (is_null_oid(oid))
        die(_("%s exists but is a symbolic ref"), other_head[i]);
      return other_head[i];
    }

  die(_("--merge requires one of the pseudorefs MERGE_HEAD, CHERRY_PICK_HEAD, REVERT_HEAD or REBASE_HEAD"));
}

static void prepare_show_merge(struct rev_info *revs)
{
  struct commit_list *bases = NULL;
  struct commit *head, *other;
  struct object_id oid;
  const char *other_name;
  const char **prune = NULL;
  int i, prune_num = 1; /* counting terminating NULL */
  struct index_state *istate = revs->repo->index;

  if (repo_get_oid(the_repository, "HEAD", &oid))
    die("--merge without HEAD?");
  head = lookup_commit_or_die(&oid, "HEAD");
  other_name = lookup_other_head(&oid);
  other = lookup_commit_or_die(&oid, other_name);
  add_pending_object(revs, &head->object, "HEAD");
  add_pending_object(revs, &other->object, other_name);
  if (repo_get_merge_bases(the_repository, head, other, &bases) < 0)
    exit(128);
  add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
  add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
  free_commit_list(bases);
  head->object.flags |= SYMMETRIC_LEFT;

  if (!istate->cache_nr)
    repo_read_index(revs->repo);
  for (i = 0; i < istate->cache_nr; i++) {
    const struct cache_entry *ce = istate->cache[i];
    if (!ce_stage(ce))
      continue;
    if (ce_path_match(istate, ce, &revs->prune_data, NULL)) {
      prune_num++;
      REALLOC_ARRAY(prune, prune_num);
      prune[prune_num-2] = ce->name;
      prune[prune_num-1] = NULL;
    }
    while ((i+1 < istate->cache_nr) &&
           ce_same_name(ce, istate->cache[i+1]))
      i++;
  }
  clear_pathspec(&revs->prune_data);
  parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
           PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
  revs->limited = 1;
  free(prune);
}

static int dotdot_missing(const char *arg, char *dotdot,
        struct rev_info *revs, int symmetric)
{
  if (revs->ignore_missing)
    return 0;
  /* de-munge so we report the full argument */
  *dotdot = '.';
  die(symmetric
      ? "Invalid symmetric difference expression %s"
      : "Invalid revision range %s", arg);
}

static int handle_dotdot_1(const char *arg, char *dotdot,
         struct rev_info *revs, int flags,
         int cant_be_filename,
         struct object_context *a_oc,
         struct object_context *b_oc)
{
  const char *a_name, *b_name;
  struct object_id a_oid, b_oid;
  struct object *a_obj, *b_obj;
  unsigned int a_flags, b_flags;
  int symmetric = 0;
  unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
  unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;

  a_name = arg;
  if (!*a_name)
    a_name = "HEAD";

  b_name = dotdot + 2;
  if (*b_name == '.') {
    symmetric = 1;
    b_name++;
  }
  if (!*b_name)
    b_name = "HEAD";

  if (get_oid_with_context(revs->repo, a_name, oc_flags, &a_oid, a_oc) ||
      get_oid_with_context(revs->repo, b_name, oc_flags, &b_oid, b_oc))
    return -1;

  if (!cant_be_filename) {
    *dotdot = '.';
    verify_non_filename(revs->prefix, arg);
    *dotdot = '\0';
  }

  a_obj = parse_object(revs->repo, &a_oid);
  b_obj = parse_object(revs->repo, &b_oid);
  if (!a_obj || !b_obj)
    return dotdot_missing(arg, dotdot, revs, symmetric);

  if (!symmetric) {
    /* just A..B */
    b_flags = flags;
    a_flags = flags_exclude;
  } else {
    /* A...B -- find merge bases between the two */
    struct commit *a, *b;
    struct commit_list *exclude = NULL;

    a = lookup_commit_reference(revs->repo, &a_obj->oid);
    b = lookup_commit_reference(revs->repo, &b_obj->oid);
    if (!a || !b)
      return dotdot_missing(arg, dotdot, revs, symmetric);

    if (repo_get_merge_bases(the_repository, a, b, &exclude) < 0) {
      free_commit_list(exclude);
      return -1;
    }
    add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
             flags_exclude);
    add_pending_commit_list(revs, exclude, flags_exclude);
    free_commit_list(exclude);

    b_flags = flags;
    a_flags = flags | SYMMETRIC_LEFT;
  }

  a_obj->flags |= a_flags;
  b_obj->flags |= b_flags;
  add_rev_cmdline(revs, a_obj, a_name, REV_CMD_LEFT, a_flags);
  add_rev_cmdline(revs, b_obj, b_name, REV_CMD_RIGHT, b_flags);
  add_pending_object_with_path(revs, a_obj, a_name, a_oc->mode, a_oc->path);
  add_pending_object_with_path(revs, b_obj, b_name, b_oc->mode, b_oc->path);
  return 0;
}

static int handle_dotdot(const char *arg,
       struct rev_info *revs, int flags,
       int cant_be_filename)
{
  struct object_context a_oc = {0}, b_oc = {0};
  char *dotdot = strstr(arg, "..");
  int ret;

  if (!dotdot)
    return -1;

  *dotdot = '\0';
  ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
            &a_oc, &b_oc);
  *dotdot = '.';

  object_context_release(&a_oc);
  object_context_release(&b_oc);
  return ret;
}

static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
{
  struct object_context oc = {0};
  char *mark;
  struct object *object;
  struct object_id oid;
  int local_flags;
  const char *arg = arg_;
  int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
  unsigned get_sha1_flags = GET_OID_RECORD_PATH;
  int ret;

  flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;

  if (!cant_be_filename && !strcmp(arg, "..")) {
    /*
     * Just ".."?  That is not a range but the
     * pathspec for the parent directory.
     */
    ret = -1;
    goto out;
  }

  if (!handle_dotdot(arg, revs, flags, revarg_opt)) {
    ret = 0;
    goto out;
  }

  mark = strstr(arg, "^@");
  if (mark && !mark[2]) {
    *mark = 0;
    if (add_parents_only(revs, arg, flags, 0)) {
      ret = 0;
      goto out;
    }
    *mark = '^';
  }
  mark = strstr(arg, "^!");
  if (mark && !mark[2]) {
    *mark = 0;
    if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
      *mark = '^';
  }
  mark = strstr(arg, "^-");
  if (mark) {
    int exclude_parent = 1;

    if (mark[2]) {
      if (strtol_i(mark + 2, 10, &exclude_parent) ||
          exclude_parent < 1) {
        ret = -1;
        goto out;
      }
    }

    *mark = 0;
    if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
      *mark = '^';
  }

  local_flags = 0;
  if (*arg == '^') {
    local_flags = UNINTERESTING | BOTTOM;
    arg++;
  }

  if (revarg_opt & REVARG_COMMITTISH)
    get_sha1_flags |= GET_OID_COMMITTISH;

  /*
   * Even if revs->do_not_die_on_missing_objects is set, we
   * should error out if we can't even get an oid, as
   * `--missing=print` should be able to report missing oids.
   */
  if (get_oid_with_context(revs->repo, arg, get_sha1_flags, &oid, &oc)) {
    ret = revs->ignore_missing ? 0 : -1;
    goto out;
  }
  if (!cant_be_filename)
    verify_non_filename(revs->prefix, arg);
  object = get_reference(revs, arg, &oid, flags ^ local_flags);
  if (!object) {
    ret = (revs->ignore_missing || revs->do_not_die_on_missing_objects) ? 0 : -1;
    goto out;
  }
  add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
  add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);

  ret = 0;

out:
  object_context_release(&oc);
  return ret;
}

int handle_revision_arg(const char *arg, struct rev_info *revs, int flags, unsigned revarg_opt)
{
  int ret = handle_revision_arg_1(arg, revs, flags, revarg_opt);
  if (!ret)
    revs->rev_input_given = 1;
  return ret;
}

static void read_pathspec_from_stdin(struct strbuf *sb,
             struct strvec *prune)
{
  while (strbuf_getline(sb, stdin) != EOF)
    strvec_push(prune, sb->buf);
}

static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
{
  append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
}

static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
{
  append_header_grep_pattern(&revs->grep_filter, field, pattern);
}

static void add_message_grep(struct rev_info *revs, const char *pattern)
{
  add_grep(revs, pattern, GREP_PATTERN_BODY);
}

static int parse_count(const char *arg)
{
  int count;

  if (strtol_i(arg, 10, &count) < 0)
    die("'%s': not an integer", arg);
  return count;
}

static timestamp_t parse_age(const char *arg)
{
  timestamp_t num;
  char *p;

  errno = 0;
  num = parse_timestamp(arg, &p, 10);
  if (errno || *p || p == arg)
    die("'%s': not a number of seconds since epoch", arg);
  return num;
}

static void overwrite_argv(int *argc, const char **argv,
         const char **value,
         const struct setup_revision_opt *opt)
{
  /*
   * Detect the case when we are overwriting ourselves. The assignment
   * itself would be a noop either way, but this lets us avoid corner
   * cases around the free() and NULL operations.
   */
  if (*value != argv[*argc]) {
    if (opt && opt->free_removed_argv_elements)
      free((char *)argv[*argc]);
    argv[*argc] = *value;
    *value = NULL;
  }
  (*argc)++;
}

static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
             int *unkc, const char **unkv,
             const struct setup_revision_opt* opt)
{
  const char *arg = argv[0];
  const char *optarg = NULL;
  int argcount;
  const unsigned hexsz = the_hash_algo->hexsz;

  /* pseudo revision arguments */
  if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
      !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
      !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
      !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
      !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
      !strcmp(arg, "--indexed-objects") ||
      !strcmp(arg, "--alternate-refs") ||
      starts_with(arg, "--exclude=") || starts_with(arg, "--exclude-hidden=") ||
      starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
      starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
  {
    overwrite_argv(unkc, unkv, &argv[0], opt);
    return 1;
  }

  if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
    revs->max_count = parse_count(optarg);
    revs->no_walk = 0;
    return argcount;
  } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
    revs->skip_count = parse_count(optarg);
    return argcount;
  } else if ((*arg == '-') && isdigit(arg[1])) {
    /* accept -<digit>, like traditional "head" */
    revs->max_count = parse_count(arg + 1);
    revs->no_walk = 0;
  } else if (!strcmp(arg, "-n")) {
    if (argc <= 1)
      return error("-n requires an argument");
    revs->max_count = parse_count(argv[1]);
    revs->no_walk = 0;
    return 2;
  } else if (skip_prefix(arg, "-n", &optarg)) {
    revs->max_count = parse_count(optarg);
    revs->no_walk = 0;
  } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
    revs->max_age = parse_age(optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
    revs->max_age = approxidate(optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("since-as-filter", argv, &optarg))) {
    revs->max_age_as_filter = approxidate(optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
    revs->max_age = approxidate(optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
    revs->min_age = parse_age(optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
    revs->min_age = approxidate(optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
    revs->min_age = approxidate(optarg);
    return argcount;
  } else if (!strcmp(arg, "--first-parent")) {
    revs->first_parent_only = 1;
  } else if (!strcmp(arg, "--exclude-first-parent-only")) {
    revs->exclude_first_parent_only = 1;
  } else if (!strcmp(arg, "--ancestry-path")) {
    revs->ancestry_path = 1;
    revs->simplify_history = 0;
    revs->limited = 1;
    revs->ancestry_path_implicit_bottoms = 1;
  } else if (skip_prefix(arg, "--ancestry-path=", &optarg)) {
    struct commit *c;
    struct object_id oid;
    const char *msg = _("could not get commit for --ancestry-path argument %s");

    revs->ancestry_path = 1;
    revs->simplify_history = 0;
    revs->limited = 1;

    if (repo_get_oid_committish(revs->repo, optarg, &oid))
      return error(msg, optarg);
    get_reference(revs, optarg, &oid, ANCESTRY_PATH);
    c = lookup_commit_reference(revs->repo, &oid);
    if (!c)
      return error(msg, optarg);
    commit_list_insert(c, &revs->ancestry_path_bottoms);
  } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
    init_reflog_walk(&revs->reflog_info);
  } else if (!strcmp(arg, "--default")) {
    if (argc <= 1)
      return error("bad --default argument");
    revs->def = argv[1];
    return 2;
  } else if (!strcmp(arg, "--merge")) {
    revs->show_merge = 1;
  } else if (!strcmp(arg, "--topo-order")) {
    revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
    revs->topo_order = 1;
  } else if (!strcmp(arg, "--simplify-merges")) {
    revs->simplify_merges = 1;
    revs->topo_order = 1;
    revs->rewrite_parents = 1;
    revs->simplify_history = 0;
    revs->limited = 1;
  } else if (!strcmp(arg, "--simplify-by-decoration")) {
    revs->simplify_merges = 1;
    revs->topo_order = 1;
    revs->rewrite_parents = 1;
    revs->simplify_history = 0;
    revs->simplify_by_decoration = 1;
    revs->limited = 1;
    revs->prune = 1;
  } else if (!strcmp(arg, "--date-order")) {
    revs->sort_order = REV_SORT_BY_COMMIT_DATE;
    revs->topo_order = 1;
  } else if (!strcmp(arg, "--author-date-order")) {
    revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
    revs->topo_order = 1;
  } else if (!strcmp(arg, "--parents")) {
    revs->rewrite_parents = 1;
    revs->print_parents = 1;
  } else if (!strcmp(arg, "--dense")) {
    revs->dense = 1;
  } else if (!strcmp(arg, "--sparse")) {
    revs->dense = 0;
  } else if (!strcmp(arg, "--in-commit-order")) {
    revs->tree_blobs_in_commit_order = 1;
  } else if (!strcmp(arg, "--remove-empty")) {
    revs->remove_empty_trees = 1;
  } else if (!strcmp(arg, "--merges")) {
    revs->min_parents = 2;
  } else if (!strcmp(arg, "--no-merges")) {
    revs->max_parents = 1;
  } else if (skip_prefix(arg, "--min-parents=", &optarg)) {
    revs->min_parents = parse_count(optarg);
  } else if (!strcmp(arg, "--no-min-parents")) {
    revs->min_parents = 0;
  } else if (skip_prefix(arg, "--max-parents=", &optarg)) {
    revs->max_parents = parse_count(optarg);
  } else if (!strcmp(arg, "--no-max-parents")) {
    revs->max_parents = -1;
  } else if (!strcmp(arg, "--boundary")) {
    revs->boundary = 1;
  } else if (!strcmp(arg, "--left-right")) {
    revs->left_right = 1;
  } else if (!strcmp(arg, "--left-only")) {
    if (revs->right_only)
      die(_("options '%s' and '%s' cannot be used together"),
          "--left-only", "--right-only/--cherry");
    revs->left_only = 1;
    revs->limited = 1;
  } else if (!strcmp(arg, "--right-only")) {
    if (revs->left_only)
      die(_("options '%s' and '%s' cannot be used together"), "--right-only", "--left-only");
    revs->right_only = 1;
    revs->limited = 1;
  } else if (!strcmp(arg, "--cherry")) {
    if (revs->left_only)
      die(_("options '%s' and '%s' cannot be used together"), "--cherry", "--left-only");
    revs->cherry_mark = 1;
    revs->right_only = 1;
    revs->max_parents = 1;
    revs->limited = 1;
  } else if (!strcmp(arg, "--count")) {
    revs->count = 1;
  } else if (!strcmp(arg, "--cherry-mark")) {
    if (revs->cherry_pick)
      die(_("options '%s' and '%s' cannot be used together"), "--cherry-mark", "--cherry-pick");
    revs->cherry_mark = 1;
    revs->limited = 1; /* needs limit_list() */
  } else if (!strcmp(arg, "--cherry-pick")) {
    if (revs->cherry_mark)
      die(_("options '%s' and '%s' cannot be used together"), "--cherry-pick", "--cherry-mark");
    revs->cherry_pick = 1;
    revs->limited = 1;
  } else if (!strcmp(arg, "--objects")) {
    revs->tag_objects = 1;
    revs->tree_objects = 1;
    revs->blob_objects = 1;
  } else if (!strcmp(arg, "--objects-edge")) {
    revs->tag_objects = 1;
    revs->tree_objects = 1;
    revs->blob_objects = 1;
    revs->edge_hint = 1;
  } else if (!strcmp(arg, "--objects-edge-aggressive")) {
    revs->tag_objects = 1;
    revs->tree_objects = 1;
    revs->blob_objects = 1;
    revs->edge_hint = 1;
    revs->edge_hint_aggressive = 1;
  } else if (!strcmp(arg, "--verify-objects")) {
    revs->tag_objects = 1;
    revs->tree_objects = 1;
    revs->blob_objects = 1;
    revs->verify_objects = 1;
    disable_commit_graph(revs->repo);
  } else if (!strcmp(arg, "--unpacked")) {
    revs->unpacked = 1;
  } else if (starts_with(arg, "--unpacked=")) {
    die(_("--unpacked=<packfile> no longer supported"));
  } else if (!strcmp(arg, "--no-kept-objects")) {
    revs->no_kept_objects = 1;
    revs->keep_pack_cache_flags |= IN_CORE_KEEP_PACKS;
    revs->keep_pack_cache_flags |= ON_DISK_KEEP_PACKS;
  } else if (skip_prefix(arg, "--no-kept-objects=", &optarg)) {
    revs->no_kept_objects = 1;
    if (!strcmp(optarg, "in-core"))
      revs->keep_pack_cache_flags |= IN_CORE_KEEP_PACKS;
    if (!strcmp(optarg, "on-disk"))
      revs->keep_pack_cache_flags |= ON_DISK_KEEP_PACKS;
  } else if (!strcmp(arg, "-r")) {
    revs->diff = 1;
    revs->diffopt.flags.recursive = 1;
  } else if (!strcmp(arg, "-t")) {
    revs->diff = 1;
    revs->diffopt.flags.recursive = 1;
    revs->diffopt.flags.tree_in_recursive = 1;
  } else if ((argcount = diff_merges_parse_opts(revs, argv))) {
    return argcount;
  } else if (!strcmp(arg, "-v")) {
    revs->verbose_header = 1;
  } else if (!strcmp(arg, "--pretty")) {
    revs->verbose_header = 1;
    revs->pretty_given = 1;
    get_commit_format(NULL, revs);
  } else if (skip_prefix(arg, "--pretty=", &optarg) ||
       skip_prefix(arg, "--format=", &optarg)) {
    /*
     * Detached form ("--pretty X" as opposed to "--pretty=X")
     * not allowed, since the argument is optional.
     */
    revs->verbose_header = 1;
    revs->pretty_given = 1;
    get_commit_format(optarg, revs);
  } else if (!strcmp(arg, "--expand-tabs")) {
    revs->expand_tabs_in_log = 8;
  } else if (!strcmp(arg, "--no-expand-tabs")) {
    revs->expand_tabs_in_log = 0;
  } else if (skip_prefix(arg, "--expand-tabs=", &arg)) {
    int val;
    if (strtol_i(arg, 10, &val) < 0 || val < 0)
      die("'%s': not a non-negative integer", arg);
    revs->expand_tabs_in_log = val;
  } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
    enable_default_display_notes(&revs->notes_opt, &revs->show_notes);
    revs->show_notes_given = 1;
  } else if (!strcmp(arg, "--show-signature")) {
    revs->show_signature = 1;
  } else if (!strcmp(arg, "--no-show-signature")) {
    revs->show_signature = 0;
  } else if (!strcmp(arg, "--show-linear-break")) {
    revs->break_bar = "                    ..........";
    revs->track_linear = 1;
    revs->track_first_time = 1;
  } else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
    revs->break_bar = xstrdup(optarg);
    revs->track_linear = 1;
    revs->track_first_time = 1;
  } else if (!strcmp(arg, "--show-notes-by-default")) {
    revs->show_notes_by_default = 1;
  } else if (skip_prefix(arg, "--show-notes=", &optarg) ||
       skip_prefix(arg, "--notes=", &optarg)) {
    if (starts_with(arg, "--show-notes=") &&
        revs->notes_opt.use_default_notes < 0)
      revs->notes_opt.use_default_notes = 1;
    enable_ref_display_notes(&revs->notes_opt, &revs->show_notes, optarg);
    revs->show_notes_given = 1;
  } else if (!strcmp(arg, "--no-notes")) {
    disable_display_notes(&revs->notes_opt, &revs->show_notes);
    revs->show_notes_given = 1;
  } else if (!strcmp(arg, "--standard-notes")) {
    revs->show_notes_given = 1;
    revs->notes_opt.use_default_notes = 1;
  } else if (!strcmp(arg, "--no-standard-notes")) {
    revs->notes_opt.use_default_notes = 0;
  } else if (!strcmp(arg, "--oneline")) {
    revs->verbose_header = 1;
    get_commit_format("oneline", revs);
    revs->pretty_given = 1;
    revs->abbrev_commit = 1;
  } else if (!strcmp(arg, "--graph")) {
    graph_clear(revs->graph);
    revs->graph = graph_init(revs);
  } else if (!strcmp(arg, "--no-graph")) {
    graph_clear(revs->graph);
    revs->graph = NULL;
  } else if (!strcmp(arg, "--encode-email-headers")) {
    revs->encode_email_headers = 1;
  } else if (!strcmp(arg, "--no-encode-email-headers")) {
    revs->encode_email_headers = 0;
  } else if (!strcmp(arg, "--root")) {
    revs->show_root_diff = 1;
  } else if (!strcmp(arg, "--no-commit-id")) {
    revs->no_commit_id = 1;
  } else if (!strcmp(arg, "--always")) {
    revs->always_show_header = 1;
  } else if (!strcmp(arg, "--no-abbrev")) {
    revs->abbrev = 0;
  } else if (!strcmp(arg, "--abbrev")) {
    revs->abbrev = DEFAULT_ABBREV;
  } else if (skip_prefix(arg, "--abbrev=", &optarg)) {
    revs->abbrev = strtoul(optarg, NULL, 10);
    if (revs->abbrev < MINIMUM_ABBREV)
      revs->abbrev = MINIMUM_ABBREV;
    else if (revs->abbrev > hexsz)
      revs->abbrev = hexsz;
  } else if (!strcmp(arg, "--abbrev-commit")) {
    revs->abbrev_commit = 1;
    revs->abbrev_commit_given = 1;
  } else if (!strcmp(arg, "--no-abbrev-commit")) {
    revs->abbrev_commit = 0;
  } else if (!strcmp(arg, "--full-diff")) {
    revs->diff = 1;
    revs->full_diff = 1;
  } else if (!strcmp(arg, "--show-pulls")) {
    revs->show_pulls = 1;
  } else if (!strcmp(arg, "--full-history")) {
    revs->simplify_history = 0;
  } else if (!strcmp(arg, "--relative-date")) {
    revs->date_mode.type = DATE_RELATIVE;
    revs->date_mode_explicit = 1;
  } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
    parse_date_format(optarg, &revs->date_mode);
    revs->date_mode_explicit = 1;
    return argcount;
  } else if (!strcmp(arg, "--log-size")) {
    revs->show_log_size = 1;
  }
  /*
   * Grepping the commit log
   */
  else if ((argcount = parse_long_opt("author", argv, &optarg))) {
    add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
    add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
    add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
    add_message_grep(revs, optarg);
    return argcount;
  } else if (!strcmp(arg, "--basic-regexp")) {
    revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_BRE;
  } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
    revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
  } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
    revs->grep_filter.ignore_case = 1;
    revs->diffopt.pickaxe_opts |= DIFF_PICKAXE_IGNORE_CASE;
  } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
    revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
  } else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {
    revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
  } else if (!strcmp(arg, "--all-match")) {
    revs->grep_filter.all_match = 1;
  } else if (!strcmp(arg, "--invert-grep")) {
    revs->grep_filter.no_body_match = 1;
  } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
    free(git_log_output_encoding);
    if (strcmp(optarg, "none"))
      git_log_output_encoding = xstrdup(optarg);
    else
      git_log_output_encoding = xstrdup("");
    return argcount;
  } else if (!strcmp(arg, "--reverse")) {
    revs->reverse ^= 1;
  } else if (!strcmp(arg, "--children")) {
    revs->children.name = "children";
    revs->limited = 1;
  } else if (!strcmp(arg, "--ignore-missing")) {
    revs->ignore_missing = 1;
  } else if (opt && opt->allow_exclude_promisor_objects &&
       !strcmp(arg, "--exclude-promisor-objects")) {
    if (fetch_if_missing)
      BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
    revs->exclude_promisor_objects = 1;
  } else {
    int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
    if (!opts)
      overwrite_argv(unkc, unkv, &argv[0], opt);
    return opts;
  }

  return 1;
}

void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
      const struct option *options,
      const char * const usagestr[])
{
  int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
            &ctx->cpidx, ctx->out, NULL);
  if (n <= 0) {
    error("unknown option `%s'", ctx->argv[0]);
    usage_with_options(usagestr, options);
  }
  ctx->argv += n;
  ctx->argc -= n;
}

void revision_opts_finish(struct rev_info *revs)
{
  if (revs->graph && revs->track_linear)
    die(_("options '%s' and '%s' cannot be used together"), "--show-linear-break", "--graph");

  if (revs->graph) {
    revs->topo_order = 1;
    revs->rewrite_parents = 1;
  }
}

static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
             void *cb_data, const char *term)
{
  struct strbuf bisect_refs = STRBUF_INIT;
  int status;
  strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
  status = refs_for_each_fullref_in(refs, bisect_refs.buf, NULL, fn, cb_data);
  strbuf_release(&bisect_refs);
  return status;
}

static int for_each_bad_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
{
  return for_each_bisect_ref(refs, fn, cb_data, term_bad);
}

static int for_each_good_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
{
  return for_each_bisect_ref(refs, fn, cb_data, term_good);
}

static int handle_revision_pseudo_opt(struct rev_info *revs,
              const char **argv, int *flags)
{
  const char *arg = argv[0];
  const char *optarg;
  struct ref_store *refs;
  int argcount;

  if (revs->repo != the_repository) {
    /*
     * We need some something like get_submodule_worktrees()
     * before we can go through all worktrees of a submodule,
     * .e.g with adding all HEADs from --all, which is not
     * supported right now, so stick to single worktree.
     */
    if (!revs->single_worktree)
      BUG("--single-worktree cannot be used together with submodule");
  }
  refs = get_main_ref_store(revs->repo);

  /*
   * NOTE!
   *
   * Commands like "git shortlog" will not accept the options below
   * unless parse_revision_opt queues them (as opposed to erroring
   * out).
   *
   * When implementing your new pseudo-option, remember to
   * register it in the list at the top of handle_revision_opt.
   */
  if (!strcmp(arg, "--all")) {
    handle_refs(refs, revs, *flags, refs_for_each_ref);
    handle_refs(refs, revs, *flags, refs_head_ref);
    if (!revs->single_worktree) {
      struct all_refs_cb cb;

      init_all_refs_cb(&cb, revs, *flags);
      other_head_refs(handle_one_ref, &cb);
    }
    clear_ref_exclusions(&revs->ref_excludes);
  } else if (!strcmp(arg, "--branches")) {
    if (revs->ref_excludes.hidden_refs_configured)
      return error(_("options '%s' and '%s' cannot be used together"),
             "--exclude-hidden", "--branches");
    handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
    clear_ref_exclusions(&revs->ref_excludes);
  } else if (!strcmp(arg, "--bisect")) {
    read_bisect_terms(&term_bad, &term_good);
    handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
    handle_refs(refs, revs, *flags ^ (UNINTERESTING | BOTTOM),
          for_each_good_bisect_ref);
    revs->bisect = 1;
  } else if (!strcmp(arg, "--tags")) {
    if (revs->ref_excludes.hidden_refs_configured)
      return error(_("options '%s' and '%s' cannot be used together"),
             "--exclude-hidden", "--tags");
    handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
    clear_ref_exclusions(&revs->ref_excludes);
  } else if (!strcmp(arg, "--remotes")) {
    if (revs->ref_excludes.hidden_refs_configured)
      return error(_("options '%s' and '%s' cannot be used together"),
             "--exclude-hidden", "--remotes");
    handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
    clear_ref_exclusions(&revs->ref_excludes);
  } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
    struct all_refs_cb cb;
    init_all_refs_cb(&cb, revs, *flags);
    refs_for_each_glob_ref(get_main_ref_store(the_repository),
               handle_one_ref, optarg, &cb);
    clear_ref_exclusions(&revs->ref_excludes);
    return argcount;
  } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
    add_ref_exclusion(&revs->ref_excludes, optarg);
    return argcount;
  } else if ((argcount = parse_long_opt("exclude-hidden", argv, &optarg))) {
    exclude_hidden_refs(&revs->ref_excludes, optarg);
    return argcount;
  } else if (skip_prefix(arg, "--branches=", &optarg)) {
    struct all_refs_cb cb;
    if (revs->ref_excludes.hidden_refs_configured)
      return error(_("options '%s' and '%s' cannot be used together"),
             "--exclude-hidden", "--branches");
    init_all_refs_cb(&cb, revs, *flags);
    refs_for_each_glob_ref_in(get_main_ref_store(the_repository),
            handle_one_ref, optarg,
            "refs/heads/", &cb);
    clear_ref_exclusions(&revs->ref_excludes);
  } else if (skip_prefix(arg, "--tags=", &optarg)) {
    struct all_refs_cb cb;
    if (revs->ref_excludes.hidden_refs_configured)
      return error(_("options '%s' and '%s' cannot be used together"),
             "--exclude-hidden", "--tags");
    init_all_refs_cb(&cb, revs, *flags);
    refs_for_each_glob_ref_in(get_main_ref_store(the_repository),
            handle_one_ref, optarg,
            "refs/tags/", &cb);
    clear_ref_exclusions(&revs->ref_excludes);
  } else if (skip_prefix(arg, "--remotes=", &optarg)) {
    struct all_refs_cb cb;
    if (revs->ref_excludes.hidden_refs_configured)
      return error(_("options '%s' and '%s' cannot be used together"),
             "--exclude-hidden", "--remotes");
    init_all_refs_cb(&cb, revs, *flags);
    refs_for_each_glob_ref_in(get_main_ref_store(the_repository),
            handle_one_ref, optarg,
            "refs/remotes/", &cb);
    clear_ref_exclusions(&revs->ref_excludes);
  } else if (!strcmp(arg, "--reflog")) {
    add_reflogs_to_pending(revs, *flags);
  } else if (!strcmp(arg, "--indexed-objects")) {
    add_index_objects_to_pending(revs, *flags);
  } else if (!strcmp(arg, "--alternate-refs")) {
    add_alternate_refs_to_pending(revs, *flags);
  } else if (!strcmp(arg, "--not")) {
    *flags ^= UNINTERESTING | BOTTOM;
  } else if (!strcmp(arg, "--no-walk")) {
    revs->no_walk = 1;
  } else if (skip_prefix(arg, "--no-walk=", &optarg)) {
    /*
     * Detached form ("--no-walk X" as opposed to "--no-walk=X")
     * not allowed, since the argument is optional.
     */
    revs->no_walk = 1;
    if (!strcmp(optarg, "sorted"))
      revs->unsorted_input = 0;
    else if (!strcmp(optarg, "unsorted"))
      revs->unsorted_input = 1;
    else
      return error("invalid argument to --no-walk");
  } else if (!strcmp(arg, "--do-walk")) {
    revs->no_walk = 0;
  } else if (!strcmp(arg, "--single-worktree")) {
    revs->single_worktree = 1;
  } else if (skip_prefix(arg, ("--filter="), &arg)) {
    parse_list_objects_filter(&revs->filter, arg);
  } else if (!strcmp(arg, ("--no-filter"))) {
    list_objects_filter_set_no_filter(&revs->filter);
  } else {
    return 0;
  }

  return 1;
}

static void read_revisions_from_stdin(struct rev_info *revs,
              struct strvec *prune)
{
  struct strbuf sb;
  int seen_dashdash = 0;
  int seen_end_of_options = 0;
  int save_warning;
  int flags = 0;

  save_warning = warn_on_object_refname_ambiguity;
  warn_on_object_refname_ambiguity = 0;

  strbuf_init(&sb, 1000);
  while (strbuf_getline(&sb, stdin) != EOF) {
    if (!sb.len)
      break;

    if (!strcmp(sb.buf, "--")) {
      seen_dashdash = 1;
      break;
    }

    if (!seen_end_of_options && sb.buf[0] == '-') {
      const char *argv[] = { sb.buf, NULL };

      if (!strcmp(sb.buf, "--end-of-options")) {
        seen_end_of_options = 1;
        continue;
      }

      if (handle_revision_pseudo_opt(revs, argv, &flags) > 0)
        continue;

      die(_("invalid option '%s' in --stdin mode"), sb.buf);
    }

    if (handle_revision_arg(sb.buf, revs, flags,
          REVARG_CANNOT_BE_FILENAME))
      die("bad revision '%s'", sb.buf);
  }
  if (seen_dashdash)
    read_pathspec_from_stdin(&sb, prune);

  strbuf_release(&sb);
  warn_on_object_refname_ambiguity = save_warning;
}

static void NORETURN diagnose_missing_default(const char *def)
{
  int flags;
  const char *refname;

  refname = refs_resolve_ref_unsafe(get_main_ref_store(the_repository),
            def, 0, NULL, &flags);
  if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
    die(_("your current branch appears to be broken"));

  skip_prefix(refname, "refs/heads/", &refname);
  die(_("your current branch '%s' does not have any commits yet"),
      refname);
}

/*
 * Parse revision information, filling in the "rev_info" structure,
 * and removing the used arguments from the argument list.
 *
 * Returns the number of arguments left that weren't recognized
 * (which are also moved to the head of the argument list)
 */
int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
{
  int i, flags, left, seen_dashdash, revarg_opt;
  struct strvec prune_data = STRVEC_INIT;
  int seen_end_of_options = 0;

  /* First, search for "--" */
  if (opt && opt->assume_dashdash) {
    seen_dashdash = 1;
  } else {
    seen_dashdash = 0;
    for (i = 1; i < argc; i++) {
      const char *arg = argv[i];
      if (strcmp(arg, "--"))
        continue;
      if (opt && opt->free_removed_argv_elements)
        free((char *)argv[i]);
      argv[i] = NULL;
      argc = i;
      if (argv[i + 1])
        strvec_pushv(&prune_data, argv + i + 1);
      seen_dashdash = 1;
      break;
    }
  }

  /* Second, deal with arguments and options */
  flags = 0;
  revarg_opt = opt ? opt->revarg_opt : 0;
  if (seen_dashdash)
    revarg_opt |= REVARG_CANNOT_BE_FILENAME;
  for (left = i = 1; i < argc; i++) {
    const char *arg = argv[i];
    if (!seen_end_of_options && *arg == '-') {
      int opts;

      opts = handle_revision_pseudo_opt(
            revs, argv + i,
            &flags);
      if (opts > 0) {
        i += opts - 1;
        continue;
      }

      if (!strcmp(arg, "--stdin")) {
        if (revs->disable_stdin) {
          overwrite_argv(&left, argv, &argv[i], opt);
          continue;
        }
        if (revs->read_from_stdin++)
          die("--stdin given twice?");
        read_revisions_from_stdin(revs, &prune_data);
        continue;
      }

      if (!strcmp(arg, "--end-of-options")) {
        seen_end_of_options = 1;
        continue;
      }

      opts = handle_revision_opt(revs, argc - i, argv + i,
               &left, argv, opt);
      if (opts > 0) {
        i += opts - 1;
        continue;
      }
      if (opts < 0)
        exit(128);
      continue;
    }


    if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
      int j;
      if (seen_dashdash || *arg == '^')
        die("bad revision '%s'", arg);

      /* If we didn't have a "--":
       * (1) all filenames must exist;
       * (2) all rev-args must not be interpretable
       *     as a valid filename.
       * but the latter we have checked in the main loop.
       */
      for (j = i; j < argc; j++)
        verify_filename(revs->prefix, argv[j], j == i);

      strvec_pushv(&prune_data, argv + i);
      break;
    }
  }
  revision_opts_finish(revs);

  if (prune_data.nr) {
    /*
     * If we need to introduce the magic "a lone ':' means no
     * pathspec whatsoever", here is the place to do so.
     *
     * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
     *  prune_data.nr = 0;
     *  prune_data.alloc = 0;
     *  free(prune_data.path);
     *  prune_data.path = NULL;
     * } else {
     *  terminate prune_data.alloc with NULL and
     *  call init_pathspec() to set revs->prune_data here.
     * }
     */
    parse_pathspec(&revs->prune_data, 0, 0,
             revs->prefix, prune_data.v);
  }
  strvec_clear(&prune_data);

  if (!revs->def)
    revs->def = opt ? opt->def : NULL;
  if (opt && opt->tweak)
    opt->tweak(revs);
  if (revs->show_merge)
    prepare_show_merge(revs);
  if (revs->def && !revs->pending.nr && !revs->rev_input_given) {
    struct object_id oid;
    struct object *object;
    struct object_context oc;
    if (get_oid_with_context(revs->repo, revs->def, 0, &oid, &oc))
      diagnose_missing_default(revs->def);
    object = get_reference(revs, revs->def, &oid, 0);
    add_pending_object_with_mode(revs, object, revs->def, oc.mode);
    object_context_release(&oc);
  }

  /* Did the user ask for any diff output? Run the diff! */
  if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
    revs->diff = 1;

  /* Pickaxe, diff-filter and rename following need diffs */
  if ((revs->diffopt.pickaxe_opts & DIFF_PICKAXE_KINDS_MASK) ||
      revs->diffopt.filter || revs->diffopt.filter_not ||
      revs->diffopt.flags.follow_renames)
    revs->diff = 1;

  if (revs->diffopt.objfind)
    revs->simplify_history = 0;

  if (revs->line_level_traverse) {
    if (want_ancestry(revs))
      revs->limited = 1;
    revs->topo_order = 1;
  }

  if (revs->topo_order && !generation_numbers_enabled(the_repository))
    revs->limited = 1;

  if (revs->prune_data.nr) {
    copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
    /* Can't prune commits with rename following: the paths change.. */
    if (!revs->diffopt.flags.follow_renames)
      revs->prune = 1;
    if (!revs->full_diff)
      copy_pathspec(&revs->diffopt.pathspec,
              &revs->prune_data);
  }

  diff_merges_setup_revs(revs);

  revs->diffopt.abbrev = revs->abbrev;

  diff_setup_done(&revs->diffopt);

  if (!is_encoding_utf8(get_log_output_encoding()))
    revs->grep_filter.ignore_locale = 1;
  compile_grep_patterns(&revs->grep_filter);

  if (revs->reflog_info && revs->limited)
    die("cannot combine --walk-reflogs with history-limiting options");
  if (revs->rewrite_parents && revs->children.name)
    die(_("options '%s' and '%s' cannot be used together"), "--parents", "--children");
  if (revs->filter.choice && !revs->blob_objects)
    die(_("object filtering requires --objects"));

  /*
   * Limitations on the graph functionality
   */
  die_for_incompatible_opt3(!!revs->graph, "--graph",
          !!revs->reverse, "--reverse",
          !!revs->reflog_info, "--walk-reflogs");

  if (revs->no_walk && revs->graph)
    die(_("options '%s' and '%s' cannot be used together"), "--no-walk", "--graph");
  if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
    die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");

  if (revs->line_level_traverse &&
      (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
    die(_("-L does not yet support diff formats besides -p and -s"));

  if (revs->expand_tabs_in_log < 0)
    revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;

  if (!revs->show_notes_given && revs->show_notes_by_default) {
    enable_default_display_notes(&revs->notes_opt, &revs->show_notes);
    revs->show_notes_given = 1;
  }

  if (argv) {
    if (opt && opt->free_removed_argv_elements)
      free((char *)argv[left]);
    argv[left] = NULL;
  }

  return left;
}

void setup_revisions_from_strvec(struct strvec *argv, struct rev_info *revs,
         struct setup_revision_opt *opt)
{
  struct setup_revision_opt fallback_opt;
  int ret;

  if (!opt) {
    memset(&fallback_opt, 0, sizeof(fallback_opt));
    opt = &fallback_opt;
  }
  opt->free_removed_argv_elements = 1;

  ret = setup_revisions(argv->nr, argv->v, revs, opt);

  for (size_t i = ret; i < argv->nr; i++)
    free((char *)argv->v[i]);
  argv->nr = ret;
}

static void release_revisions_cmdline(struct rev_cmdline_info *cmdline)
{
  unsigned int i;

  for (i = 0; i < cmdline->nr; i++)
    free((char *)cmdline->rev[i].name);
  free(cmdline->rev);
}

static void release_revisions_mailmap(struct string_list *mailmap)
{
  if (!mailmap)
    return;
  clear_mailmap(mailmap);
  free(mailmap);
}

static void release_revisions_topo_walk_info(struct topo_walk_info *info);

static void release_revisions_bloom_keyvecs(struct rev_info *revs)
{
  for (size_t nr = 0; nr < revs->bloom_keyvecs_nr; nr++)
    bloom_keyvec_free(revs->bloom_keyvecs[nr]);
  FREE_AND_NULL(revs->bloom_keyvecs);
  revs->bloom_keyvecs_nr = 0;
}

static void free_void_commit_list(void *list)
{
  free_commit_list(list);
}

void release_revisions(struct rev_info *revs)
{
  free_commit_list(revs->commits);
  free_commit_list(revs->ancestry_path_bottoms);
  release_display_notes(&revs->notes_opt);
  object_array_clear(&revs->pending);
  object_array_clear(&revs->boundary_commits);
  release_revisions_cmdline(&revs->cmdline);
  list_objects_filter_release(&revs->filter);
  clear_pathspec(&revs->prune_data);
  date_mode_release(&revs->date_mode);
  release_revisions_mailmap(revs->mailmap);
  free_grep_patterns(&revs->grep_filter);
  graph_clear(revs->graph);
  diff_free(&revs->diffopt);
  diff_free(&revs->pruning);
  reflog_walk_info_release(revs->reflog_info);
  release_revisions_topo_walk_info(revs->topo_walk_info);
  clear_decoration(&revs->children, free_void_commit_list);
  clear_decoration(&revs->merge_simplification, free);
  clear_decoration(&revs->treesame, free);
  line_log_free(revs);
  oidset_clear(&revs->missing_commits);
  release_revisions_bloom_keyvecs(revs);
}

static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
{
  struct commit_list *l = xcalloc(1, sizeof(*l));

  l->item = child;
  l->next = add_decoration(&revs->children, &parent->object, l);
}

static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
{
  struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
  struct commit_list **pp, *p;
  int surviving_parents;

  /* Examine existing parents while marking ones we have seen... */
  pp = &commit->parents;
  surviving_parents = 0;
  while ((p = *pp) != NULL) {
    struct commit *parent = p->item;
    if (parent->object.flags & TMP_MARK) {
      *pp = p->next;
      free(p);
      if (ts)
        compact_treesame(revs, commit, surviving_parents);
      continue;
    }
    parent->object.flags |= TMP_MARK;
    surviving_parents++;
    pp = &p->next;
  }
  /* clear the temporary mark */
  for (p = commit->parents; p; p = p->next) {
    p->item->object.flags &= ~TMP_MARK;
  }
  /* no update_treesame() - removing duplicates can't affect TREESAME */
  return surviving_parents;
}

struct merge_simplify_state {
  struct commit *simplified;
};

static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
{
  struct merge_simplify_state *st;

  st = lookup_decoration(&revs->merge_simplification, &commit->object);
  if (!st) {
    CALLOC_ARRAY(st, 1);
    add_decoration(&revs->merge_simplification, &commit->object, st);
  }
  return st;
}

static int mark_redundant_parents(struct commit *commit)
{
  struct commit_list *h = reduce_heads(commit->parents);
  int i = 0, marked = 0;
  struct commit_list *po, *pn;

  /* Want these for sanity-checking only */
  int orig_cnt = commit_list_count(commit->parents);
  int cnt = commit_list_count(h);

  /*
   * Not ready to remove items yet, just mark them for now, based
   * on the output of reduce_heads(). reduce_heads outputs the reduced
   * set in its original order, so this isn't too hard.
   */
  po = commit->parents;
  pn = h;
  while (po) {
    if (pn && po->item == pn->item) {
      pn = pn->next;
      i++;
    } else {
      po->item->object.flags |= TMP_MARK;
      marked++;
    }
    po=po->next;
  }

  if (i != cnt || cnt+marked != orig_cnt)
    die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);

  free_commit_list(h);

  return marked;
}

static int mark_treesame_root_parents(struct commit *commit)
{
  struct commit_list *p;
  int marked = 0;

  for (p = commit->parents; p; p = p->next) {
    struct commit *parent = p->item;
    if (!parent->parents && (parent->object.flags & TREESAME)) {
      parent->object.flags |= TMP_MARK;
      marked++;
    }
  }

  return marked;
}

/*
 * Awkward naming - this means one parent we are TREESAME to.
 * cf mark_treesame_root_parents: root parents that are TREESAME (to an
 * empty tree). Better name suggestions?
 */
static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
{
  struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
  struct commit *unmarked = NULL, *marked = NULL;
  struct commit_list *p;
  unsigned n;

  for (p = commit->parents, n = 0; p; p = p->next, n++) {
    if (ts->treesame[n]) {
      if (p->item->object.flags & TMP_MARK) {
        if (!marked)
          marked = p->item;
      } else {
        if (!unmarked) {
          unmarked = p->item;
          break;
        }
      }
    }
  }

  /*
   * If we are TREESAME to a marked-for-deletion parent, but not to any
   * unmarked parents, unmark the first TREESAME parent. This is the
   * parent that the default simplify_history==1 scan would have followed,
   * and it doesn't make sense to omit that path when asking for a
   * simplified full history. Retaining it improves the chances of
   * understanding odd missed merges that took an old version of a file.
   *
   * Example:
   *
   *   I--------*X       A modified the file, but mainline merge X used
   *    \       /        "-s ours", so took the version from I. X is
   *     `-*A--'         TREESAME to I and !TREESAME to A.
   *
   * Default log from X would produce "I". Without this check,
   * --full-history --simplify-merges would produce "I-A-X", showing
   * the merge commit X and that it changed A, but not making clear that
   * it had just taken the I version. With this check, the topology above
   * is retained.
   *
   * Note that it is possible that the simplification chooses a different
   * TREESAME parent from the default, in which case this test doesn't
   * activate, and we _do_ drop the default parent. Example:
   *
   *   I------X         A modified the file, but it was reverted in B,
   *    \    /          meaning mainline merge X is TREESAME to both
   *    *A-*B           parents.
   *
   * Default log would produce "I" by following the first parent;
   * --full-history --simplify-merges will produce "I-A-B". But this is a
   * reasonable result - it presents a logical full history leading from
   * I to X, and X is not an important merge.
   */
  if (!unmarked && marked) {
    marked->object.flags &= ~TMP_MARK;
    return 1;
  }

  return 0;
}

static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
{
  struct commit_list **pp, *p;
  int nth_parent, removed = 0;

  pp = &commit->parents;
  nth_parent = 0;
  while ((p = *pp) != NULL) {
    struct commit *parent = p->item;
    if (parent->object.flags & TMP_MARK) {
      parent->object.flags &= ~TMP_MARK;
      *pp = p->next;
      free(p);
      removed++;
      compact_treesame(revs, commit, nth_parent);
      continue;
    }
    pp = &p->next;
    nth_parent++;
  }

  /* Removing parents can only increase TREESAMEness */
  if (removed && !(commit->object.flags & TREESAME))
    update_treesame(revs, commit);

  return nth_parent;
}

static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
{
  struct commit_list *p;
  struct commit *parent;
  struct merge_simplify_state *st, *pst;
  int cnt;

  st = locate_simplify_state(revs, commit);

  /*
   * Have we handled this one?
   */
  if (st->simplified)
    return tail;

  /*
   * An UNINTERESTING commit simplifies to itself, so does a
   * root commit.  We do not rewrite parents of such commit
   * anyway.
   */
  if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
    st->simplified = commit;
    return tail;
  }

  /*
   * Do we know what commit all of our parents that matter
   * should be rewritten to?  Otherwise we are not ready to
   * rewrite this one yet.
   */
  for (cnt = 0, p = commit->parents; p; p = p->next) {
    pst = locate_simplify_state(revs, p->item);
    if (!pst->simplified) {
      tail = &commit_list_insert(p->item, tail)->next;
      cnt++;
    }
    if (revs->first_parent_only)
      break;
  }
  if (cnt) {
    tail = &commit_list_insert(commit, tail)->next;
    return tail;
  }

  /*
   * Rewrite our list of parents. Note that this cannot
   * affect our TREESAME flags in any way - a commit is
   * always TREESAME to its simplification.
   */
  for (p = commit->parents; p; p = p->next) {
    pst = locate_simplify_state(revs, p->item);
    p->item = pst->simplified;
    if (revs->first_parent_only)
      break;
  }

  if (revs->first_parent_only)
    cnt = 1;
  else
    cnt = remove_duplicate_parents(revs, commit);

  /*
   * It is possible that we are a merge and one side branch
   * does not have any commit that touches the given paths;
   * in such a case, the immediate parent from that branch
   * will be rewritten to be the merge base.
   *
   *      o----X    X: the commit we are looking at;
   *     /    /   o: a commit that touches the paths;
   * ---o----'
   *
   * Further, a merge of an independent branch that doesn't
   * touch the path will reduce to a treesame root parent:
   *
   *  ----o----X    X: the commit we are looking at;
   *          /   o: a commit that touches the paths;
   *         r    r: a root commit not touching the paths
   *
   * Detect and simplify both cases.
   */
  if (1 < cnt) {
    int marked = mark_redundant_parents(commit);
    marked += mark_treesame_root_parents(commit);
    if (marked)
      marked -= leave_one_treesame_to_parent(revs, commit);
    if (marked)
      cnt = remove_marked_parents(revs, commit);
  }

  /*
   * A commit simplifies to itself if it is a root, if it is
   * UNINTERESTING, if it touches the given paths, or if it is a
   * merge and its parents don't simplify to one relevant commit
   * (the first two cases are already handled at the beginning of
   * this function).
   *
   * Otherwise, it simplifies to what its sole relevant parent
   * simplifies to.
   */
  if (!cnt ||
      (commit->object.flags & UNINTERESTING) ||
      !(commit->object.flags & TREESAME) ||
      (parent = one_relevant_parent(revs, commit->parents)) == NULL ||
      (revs->show_pulls && (commit->object.flags & PULL_MERGE)))
    st->simplified = commit;
  else {
    pst = locate_simplify_state(revs, parent);
    st->simplified = pst->simplified;
  }
  return tail;
}

static void simplify_merges(struct rev_info *revs)
{
  struct commit_list *list, *next;
  struct commit_list *yet_to_do, **tail;
  struct commit *commit;

  if (!revs->prune)
    return;

  /* feed the list reversed */
  yet_to_do = NULL;
  for (list = revs->commits; list; list = next) {
    commit = list->item;
    next = list->next;
    /*
     * Do not free(list) here yet; the original list
     * is used later in this function.
     */
    commit_list_insert(commit, &yet_to_do);
  }
  while (yet_to_do) {
    list = yet_to_do;
    yet_to_do = NULL;
    tail = &yet_to_do;
    while (list) {
      commit = pop_commit(&list);
      tail = simplify_one(revs, commit, tail);
    }
  }

  /* clean up the result, removing the simplified ones */
  list = revs->commits;
  revs->commits = NULL;
  tail = &revs->commits;
  while (list) {
    struct merge_simplify_state *st;

    commit = pop_commit(&list);
    st = locate_simplify_state(revs, commit);
    if (st->simplified == commit)
      tail = &commit_list_insert(commit, tail)->next;
  }
}

static void set_children(struct rev_info *revs)
{
  struct commit_list *l;
  for (l = revs->commits; l; l = l->next) {
    struct commit *commit = l->item;
    struct commit_list *p;

    for (p = commit->parents; p; p = p->next)
      add_child(revs, p->item, commit);
  }
}

void reset_revision_walk(void)
{
  clear_object_flags(the_repository,
         SEEN | ADDED | SHOWN | TOPO_WALK_EXPLORED | TOPO_WALK_INDEGREE);
}

static int mark_uninteresting(const struct object_id *oid,
            struct packed_git *pack UNUSED,
            uint32_t pos UNUSED,
            void *cb)
{
  struct rev_info *revs = cb;
  struct object *o = lookup_unknown_object(revs->repo, oid);
  o->flags |= UNINTERESTING | SEEN;
  return 0;
}

define_commit_slab(indegree_slab, int);
define_commit_slab(author_date_slab, timestamp_t);

struct topo_walk_info {
  timestamp_t min_generation;
  struct prio_queue explore_queue;
  struct prio_queue indegree_queue;
  struct prio_queue topo_queue;
  struct indegree_slab indegree;
  struct author_date_slab author_date;
};

static int topo_walk_atexit_registered;
static unsigned int count_explore_walked;
static unsigned int count_indegree_walked;
static unsigned int count_topo_walked;

static void trace2_topo_walk_statistics_atexit(void)
{
  struct json_writer jw = JSON_WRITER_INIT;

  jw_object_begin(&jw, 0);
  jw_object_intmax(&jw, "count_explore_walked", count_explore_walked);
  jw_object_intmax(&jw, "count_indegree_walked", count_indegree_walked);
  jw_object_intmax(&jw, "count_topo_walked", count_topo_walked);
  jw_end(&jw);

  trace2_data_json("topo_walk", the_repository, "statistics", &jw);

  jw_release(&jw);
}

static inline void test_flag_and_insert(struct prio_queue *q, struct commit *c, int flag)
{
  if (c->object.flags & flag)
    return;

  c->object.flags |= flag;
  prio_queue_put(q, c);
}

static void explore_walk_step(struct rev_info *revs)
{
  struct topo_walk_info *info = revs->topo_walk_info;
  struct commit_list *p;
  struct commit *c = prio_queue_get(&info->explore_queue);

  if (!c)
    return;

  if (repo_parse_commit_gently(revs->repo, c, 1) < 0)
    return;

  count_explore_walked++;

  if (revs->sort_order == REV_SORT_BY_AUTHOR_DATE)
    record_author_date(&info->author_date, c);

  if (revs->max_age != -1 && (c->date < revs->max_age))
    c->object.flags |= UNINTERESTING;

  if (process_parents(revs, c, NULL, NULL) < 0)
    return;

  if (c->object.flags & UNINTERESTING)
    mark_parents_uninteresting(revs, c);

  for (p = c->parents; p; p = p->next)
    test_flag_and_insert(&info->explore_queue, p->item, TOPO_WALK_EXPLORED);
}

static void explore_to_depth(struct rev_info *revs,
           timestamp_t gen_cutoff)
{
  struct topo_walk_info *info = revs->topo_walk_info;
  struct commit *c;
  while ((c = prio_queue_peek(&info->explore_queue)) &&
         commit_graph_generation(c) >= gen_cutoff)
    explore_walk_step(revs);
}

static void indegree_walk_step(struct rev_info *revs)
{
  struct commit_list *p;
  struct topo_walk_info *info = revs->topo_walk_info;
  struct commit *c = prio_queue_get(&info->indegree_queue);

  if (!c)
    return;

  if (repo_parse_commit_gently(revs->repo, c, 1) < 0)
    return;

  count_indegree_walked++;

  explore_to_depth(revs, commit_graph_generation(c));

  for (p = c->parents; p; p = p->next) {
    struct commit *parent = p->item;
    int *pi = indegree_slab_at(&info->indegree, parent);

    if (repo_parse_commit_gently(revs->repo, parent, 1) < 0)
      return;

    if (*pi)
      (*pi)++;
    else
      *pi = 2;

    test_flag_and_insert(&info->indegree_queue, parent, TOPO_WALK_INDEGREE);

    if (revs->first_parent_only)
      return;
  }
}

static void compute_indegrees_to_depth(struct rev_info *revs,
               timestamp_t gen_cutoff)
{
  struct topo_walk_info *info = revs->topo_walk_info;
  struct commit *c;
  while ((c = prio_queue_peek(&info->indegree_queue)) &&
         commit_graph_generation(c) >= gen_cutoff)
    indegree_walk_step(revs);
}

static void release_revisions_topo_walk_info(struct topo_walk_info *info)
{
  if (!info)
    return;
  clear_prio_queue(&info->explore_queue);
  clear_prio_queue(&info->indegree_queue);
  clear_prio_queue(&info->topo_queue);
  clear_indegree_slab(&info->indegree);
  clear_author_date_slab(&info->author_date);
  free(info);
}

static void reset_topo_walk(struct rev_info *revs)
{
  release_revisions_topo_walk_info(revs->topo_walk_info);
  revs->topo_walk_info = NULL;
}

static void init_topo_walk(struct rev_info *revs)
{
  struct topo_walk_info *info;
  struct commit_list *list;
  if (revs->topo_walk_info)
    reset_topo_walk(revs);

  revs->topo_walk_info = xmalloc(sizeof(struct topo_walk_info));
  info = revs->topo_walk_info;
  memset(info, 0, sizeof(struct topo_walk_info));

  init_indegree_slab(&info->indegree);
  memset(&info->explore_queue, 0, sizeof(info->explore_queue));
  memset(&info->indegree_queue, 0, sizeof(info->indegree_queue));
  memset(&info->topo_queue, 0, sizeof(info->topo_queue));

  switch (revs->sort_order) {
  default: /* REV_SORT_IN_GRAPH_ORDER */
    info->topo_queue.compare = NULL;
    break;
  case REV_SORT_BY_COMMIT_DATE:
    info->topo_queue.compare = compare_commits_by_commit_date;
    break;
  case REV_SORT_BY_AUTHOR_DATE:
    init_author_date_slab(&info->author_date);
    info->topo_queue.compare = compare_commits_by_author_date;
    info->topo_queue.cb_data = &info->author_date;
    break;
  }

  info->explore_queue.compare = compare_commits_by_gen_then_commit_date;
  info->indegree_queue.compare = compare_commits_by_gen_then_commit_date;

  info->min_generation = GENERATION_NUMBER_INFINITY;
  for (list = revs->commits; list; list = list->next) {
    struct commit *c = list->item;
    timestamp_t generation;

    if (repo_parse_commit_gently(revs->repo, c, 1))
      continue;

    test_flag_and_insert(&info->explore_queue, c, TOPO_WALK_EXPLORED);
    test_flag_and_insert(&info->indegree_queue, c, TOPO_WALK_INDEGREE);

    generation = commit_graph_generation(c);
    if (generation < info->min_generation)
      info->min_generation = generation;

    *(indegree_slab_at(&info->indegree, c)) = 1;

    if (revs->sort_order == REV_SORT_BY_AUTHOR_DATE)
      record_author_date(&info->author_date, c);
  }
  compute_indegrees_to_depth(revs, info->min_generation);

  for (list = revs->commits; list; list = list->next) {
    struct commit *c = list->item;

    if (*(indegree_slab_at(&info->indegree, c)) == 1)
      prio_queue_put(&info->topo_queue, c);
  }

  /*
   * This is unfortunate; the initial tips need to be shown
   * in the order given from the revision traversal machinery.
   */
  if (revs->sort_order == REV_SORT_IN_GRAPH_ORDER)
    prio_queue_reverse(&info->topo_queue);

  if (trace2_is_enabled() && !topo_walk_atexit_registered) {
    atexit(trace2_topo_walk_statistics_atexit);
    topo_walk_atexit_registered = 1;
  }
}

static struct commit *next_topo_commit(struct rev_info *revs)
{
  struct commit *c;
  struct topo_walk_info *info = revs->topo_walk_info;

  /* pop next off of topo_queue */
  c = prio_queue_get(&info->topo_queue);

  if (c)
    *(indegree_slab_at(&info->indegree, c)) = 0;

  return c;
}

static void expand_topo_walk(struct rev_info *revs, struct commit *commit)
{
  struct commit_list *p;
  struct topo_walk_info *info = revs->topo_walk_info;
  if (process_parents(revs, commit, NULL, NULL) < 0) {
    if (!revs->ignore_missing_links)
      die("Failed to traverse parents of commit %s",
          oid_to_hex(&commit->object.oid));
  }

  count_topo_walked++;

  for (p = commit->parents; p; p = p->next) {
    struct commit *parent = p->item;
    int *pi;
    timestamp_t generation;

    if (parent->object.flags & UNINTERESTING)
      continue;

    if (repo_parse_commit_gently(revs->repo, parent, 1) < 0)
      continue;

    generation = commit_graph_generation(parent);
    if (generation < info->min_generation) {
      info->min_generation = generation;
      compute_indegrees_to_depth(revs, info->min_generation);
    }

    pi = indegree_slab_at(&info->indegree, parent);

    (*pi)--;
    if (*pi == 1)
      prio_queue_put(&info->topo_queue, parent);

    if (revs->first_parent_only)
      return;
  }
}

int prepare_revision_walk(struct rev_info *revs)
{
  int i;
  struct object_array old_pending;
  struct commit_list **next = &revs->commits;

  memcpy(&old_pending, &revs->pending, sizeof(old_pending));
  revs->pending.nr = 0;
  revs->pending.alloc = 0;
  revs->pending.objects = NULL;
  for (i = 0; i < old_pending.nr; i++) {
    struct object_array_entry *e = old_pending.objects + i;
    struct commit *commit = handle_commit(revs, e);
    if (commit) {
      if (!(commit->object.flags & SEEN)) {
        commit->object.flags |= SEEN;
        next = commit_list_append(commit, next);
      }
    }
  }
  object_array_clear(&old_pending);

  /* Signal whether we need per-parent treesame decoration */
  if (revs->simplify_merges ||
      (revs->limited && limiting_can_increase_treesame(revs)))
    revs->treesame.name = "treesame";

  if (revs->exclude_promisor_objects) {
    for_each_packed_object(revs->repo, mark_uninteresting, revs,
               FOR_EACH_OBJECT_PROMISOR_ONLY);
  }

  if (!revs->reflog_info)
    prepare_to_use_bloom_filter(revs);
  if (!revs->unsorted_input)
    commit_list_sort_by_date(&revs->commits);
  if (revs->no_walk)
    return 0;
  if (revs->limited) {
    if (limit_list(revs) < 0)
      return -1;
    if (revs->topo_order)
      sort_in_topological_order(&revs->commits, revs->sort_order);
  } else if (revs->topo_order)
    init_topo_walk(revs);
  if (revs->line_level_traverse && want_ancestry(revs))
    /*
     * At the moment we can only do line-level log with parent
     * rewriting by performing this expensive pre-filtering step.
     * If parent rewriting is not requested, then we rather
     * perform the line-level log filtering during the regular
     * history traversal.
     */
    line_log_filter(revs);
  if (revs->simplify_merges)
    simplify_merges(revs);
  if (revs->children.name)
    set_children(revs);

  return 0;
}

static enum rewrite_result rewrite_one_1(struct rev_info *revs,
           struct commit **pp,
           struct prio_queue *queue)
{
  for (;;) {
    struct commit *p = *pp;
    if (!revs->limited)
      if (process_parents(revs, p, NULL, queue) < 0)
        return rewrite_one_error;
    if (p->object.flags & UNINTERESTING)
      return rewrite_one_ok;
    if (!(p->object.flags & TREESAME))
      return rewrite_one_ok;
    if (!p->parents)
      return rewrite_one_noparents;
    if (!(p = one_relevant_parent(revs, p->parents)))
      return rewrite_one_ok;
    *pp = p;
  }
}

static void merge_queue_into_list(struct prio_queue *q, struct commit_list **list)
{
  while (q->nr) {
    struct commit *item = prio_queue_peek(q);
    struct commit_list *p = *list;

    if (p && p->item->date >= item->date)
      list = &p->next;
    else {
      p = commit_list_insert(item, list);
      list = &p->next; /* skip newly added item */
      prio_queue_get(q); /* pop item */
    }
  }
}

static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
{
  struct prio_queue queue = { compare_commits_by_commit_date };
  enum rewrite_result ret = rewrite_one_1(revs, pp, &queue);
  merge_queue_into_list(&queue, &revs->commits);
  clear_prio_queue(&queue);
  return ret;
}

int rewrite_parents(struct rev_info *revs, struct commit *commit,
  rewrite_parent_fn_t rewrite_parent)
{
  struct commit_list **pp = &commit->parents;
  while (*pp) {
    struct commit_list *parent = *pp;
    switch (rewrite_parent(revs, &parent->item)) {
    case rewrite_one_ok:
      break;
    case rewrite_one_noparents:
      *pp = parent->next;
      free(parent);
      continue;
    case rewrite_one_error:
      return -1;
    }
    pp = &parent->next;
  }
  remove_duplicate_parents(revs, commit);
  return 0;
}

static int commit_match(struct commit *commit, struct rev_info *opt)
{
  int retval;
  const char *encoding;
  const char *message;
  struct strbuf buf = STRBUF_INIT;

  if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
    return 1;

  /* Prepend "fake" headers as needed */
  if (opt->grep_filter.use_reflog_filter) {
    strbuf_addstr(&buf, "reflog ");
    get_reflog_message(&buf, opt->reflog_info);
    strbuf_addch(&buf, '\n');
  }

  /*
   * We grep in the user's output encoding, under the assumption that it
   * is the encoding they are most likely to write their grep pattern
   * for. In addition, it means we will match the "notes" encoding below,
   * so we will not end up with a buffer that has two different encodings
   * in it.
   */
  encoding = get_log_output_encoding();
  message = repo_logmsg_reencode(the_repository, commit, NULL, encoding);

  /* Copy the commit to temporary if we are using "fake" headers */
  if (buf.len)
    strbuf_addstr(&buf, message);

  if (opt->grep_filter.header_list && opt->mailmap) {
    const char *commit_headers[] = { "author ", "committer ", NULL };

    if (!buf.len)
      strbuf_addstr(&buf, message);

    apply_mailmap_to_header(&buf, commit_headers, opt->mailmap);
  }

  /* Append "fake" message parts as needed */
  if (opt->show_notes) {
    if (!buf.len)
      strbuf_addstr(&buf, message);
    format_display_notes(&commit->object.oid, &buf, encoding, 1);
  }

  /*
   * Find either in the original commit message, or in the temporary.
   * Note that we cast away the constness of "message" here. It is
   * const because it may come from the cached commit buffer. That's OK,
   * because we know that it is modifiable heap memory, and that while
   * grep_buffer may modify it for speed, it will restore any
   * changes before returning.
   */
  if (buf.len)
    retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
  else
    retval = grep_buffer(&opt->grep_filter,
             (char *)message, strlen(message));
  strbuf_release(&buf);
  repo_unuse_commit_buffer(the_repository, commit, message);
  return retval;
}

static inline int want_ancestry(const struct rev_info *revs)
{
  return (revs->rewrite_parents || revs->children.name);
}

/*
 * Return a timestamp to be used for --since/--until comparisons for this
 * commit, based on the revision options.
 */
static timestamp_t comparison_date(const struct rev_info *revs,
           struct commit *commit)
{
  return revs->reflog_info ?
    get_reflog_timestamp(revs->reflog_info) :
    commit->date;
}

enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
{
  if (commit->object.flags & SHOWN)
    return commit_ignore;
  if (revs->unpacked && has_object_pack(revs->repo, &commit->object.oid))
    return commit_ignore;
  if (revs->no_kept_objects) {
    if (has_object_kept_pack(revs->repo, &commit->object.oid,
           revs->keep_pack_cache_flags))
      return commit_ignore;
  }
  if (commit->object.flags & UNINTERESTING)
    return commit_ignore;
  if (revs->line_level_traverse && !want_ancestry(revs)) {
    /*
     * In case of line-level log with parent rewriting
     * prepare_revision_walk() already took care of all line-level
     * log filtering, and there is nothing left to do here.
     *
     * If parent rewriting was not requested, then this is the
     * place to perform the line-level log filtering.  Notably,
     * this check, though expensive, must come before the other,
     * cheaper filtering conditions, because the tracked line
     * ranges must be adjusted even when the commit will end up
     * being ignored based on other conditions.
     */
    if (!line_log_process_ranges_arbitrary_commit(revs, commit))
      return commit_ignore;
  }
  if (revs->min_age != -1 &&
      comparison_date(revs, commit) > revs->min_age)
      return commit_ignore;
  if (revs->max_age_as_filter != -1 &&
      comparison_date(revs, commit) < revs->max_age_as_filter)
      return commit_ignore;
  if (revs->min_parents || (revs->max_parents >= 0)) {
    int n = commit_list_count(commit->parents);
    if ((n < revs->min_parents) ||
        ((revs->max_parents >= 0) && (n > revs->max_parents)))
      return commit_ignore;
  }
  if (!commit_match(commit, revs))
    return commit_ignore;
  if (revs->prune && revs->dense) {
    /* Commit without changes? */
    if (commit->object.flags & TREESAME) {
      int n;
      struct commit_list *p;
      /* drop merges unless we want parenthood */
      if (!want_ancestry(revs))
        return commit_ignore;

      if (revs->show_pulls && (commit->object.flags & PULL_MERGE))
        return commit_show;

      /*
       * If we want ancestry, then need to keep any merges
       * between relevant commits to tie together topology.
       * For consistency with TREESAME and simplification
       * use "relevant" here rather than just INTERESTING,
       * to treat bottom commit(s) as part of the topology.
       */
      for (n = 0, p = commit->parents; p; p = p->next)
        if (relevant_commit(p->item))
          if (++n >= 2)
            return commit_show;
      return commit_ignore;
    }
  }
  return commit_show;
}

define_commit_slab(saved_parents, struct commit_list *);

#define EMPTY_PARENT_LIST ((struct commit_list *)-1)

/*
 * You may only call save_parents() once per commit (this is checked
 * for non-root commits).
 */
static void save_parents(struct rev_info *revs, struct commit *commit)
{
  struct commit_list **pp;

  if (!revs->saved_parents_slab) {
    revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
    init_saved_parents(revs->saved_parents_slab);
  }

  pp = saved_parents_at(revs->saved_parents_slab, commit);

  /*
   * When walking with reflogs, we may visit the same commit
   * several times: once for each appearance in the reflog.
   *
   * In this case, save_parents() will be called multiple times.
   * We want to keep only the first set of parents.  We need to
   * store a sentinel value for an empty (i.e., NULL) parent
   * list to distinguish it from a not-yet-saved list, however.
   */
  if (*pp)
    return;
  if (commit->parents)
    *pp = copy_commit_list(commit->parents);
  else
    *pp = EMPTY_PARENT_LIST;
}

static void free_saved_parent(struct commit_list **parents)
{
  if (*parents != EMPTY_PARENT_LIST)
    free_commit_list(*parents);
}

static void free_saved_parents(struct rev_info *revs)
{
  if (!revs->saved_parents_slab)
    return;
  deep_clear_saved_parents(revs->saved_parents_slab, free_saved_parent);
  FREE_AND_NULL(revs->saved_parents_slab);
}

struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
{
  struct commit_list *parents;

  if (!revs->saved_parents_slab)
    return commit->parents;

  parents = *saved_parents_at(revs->saved_parents_slab, commit);
  if (parents == EMPTY_PARENT_LIST)
    return NULL;
  return parents;
}

enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
{
  enum commit_action action = get_commit_action(revs, commit);

  if (action == commit_show &&
      revs->prune && revs->dense && want_ancestry(revs)) {
    /*
     * --full-diff on simplified parents is no good: it
     * will show spurious changes from the commits that
     * were elided.  So we save the parents on the side
     * when --full-diff is in effect.
     */
    if (revs->full_diff)
      save_parents(revs, commit);
    if (rewrite_parents(revs, commit, rewrite_one) < 0)
      return commit_error;
  }
  return action;
}

static void track_linear(struct rev_info *revs, struct commit *commit)
{
  if (revs->track_first_time) {
    revs->linear = 1;
    revs->track_first_time = 0;
  } else {
    struct commit_list *p;
    for (p = revs->previous_parents; p; p = p->next)
      if (p->item == NULL || /* first commit */
          oideq(&p->item->object.oid, &commit->object.oid))
        break;
    revs->linear = p != NULL;
  }
  if (revs->reverse) {
    if (revs->linear)
      commit->object.flags |= TRACK_LINEAR;
  }
  free_commit_list(revs->previous_parents);
  revs->previous_parents = copy_commit_list(commit->parents);
}

static struct commit *get_revision_1(struct rev_info *revs)
{
  while (1) {
    struct commit *commit;

    if (revs->reflog_info)
      commit = next_reflog_entry(revs->reflog_info);
    else if (revs->topo_walk_info)
      commit = next_topo_commit(revs);
    else
      commit = pop_commit(&revs->commits);

    if (!commit)
      return NULL;

    if (revs->reflog_info)
      commit->object.flags &= ~(ADDED | SEEN | SHOWN);

    /*
     * If we haven't done the list limiting, we need to look at
     * the parents here. We also need to do the date-based limiting
     * that we'd otherwise have done in limit_list().
     */
    if (!revs->limited) {
      if (revs->max_age != -1 &&
          comparison_date(revs, commit) < revs->max_age)
        continue;

      if (revs->reflog_info)
        try_to_simplify_commit(revs, commit);
      else if (revs->topo_walk_info)
        expand_topo_walk(revs, commit);
      else if (process_parents(revs, commit, &revs->commits, NULL) < 0) {
        if (!revs->ignore_missing_links)
          die("Failed to traverse parents of commit %s",
            oid_to_hex(&commit->object.oid));
      }
    }

    switch (simplify_commit(revs, commit)) {
    case commit_ignore:
      continue;
    case commit_error:
      die("Failed to simplify parents of commit %s",
          oid_to_hex(&commit->object.oid));
    default:
      if (revs->track_linear)
        track_linear(revs, commit);
      return commit;
    }
  }
}

/*
 * Return true for entries that have not yet been shown.  (This is an
 * object_array_each_func_t.)
 */
static int entry_unshown(struct object_array_entry *entry, void *cb_data UNUSED)
{
  return !(entry->item->flags & SHOWN);
}

/*
 * If array is on the verge of a realloc, garbage-collect any entries
 * that have already been shown to try to free up some space.
 */
static void gc_boundary(struct object_array *array)
{
  if (array->nr == array->alloc)
    object_array_filter(array, entry_unshown, NULL);
}

static void create_boundary_commit_list(struct rev_info *revs)
{
  unsigned i;
  struct commit *c;
  struct object_array *array = &revs->boundary_commits;
  struct object_array_entry *objects = array->objects;

  /*
   * If revs->commits is non-NULL at this point, an error occurred in
   * get_revision_1().  Ignore the error and continue printing the
   * boundary commits anyway.  (This is what the code has always
   * done.)
   */
  free_commit_list(revs->commits);
  revs->commits = NULL;

  /*
   * Put all of the actual boundary commits from revs->boundary_commits
   * into revs->commits
   */
  for (i = 0; i < array->nr; i++) {
    c = (struct commit *)(objects[i].item);
    if (!c)
      continue;
    if (!(c->object.flags & CHILD_SHOWN))
      continue;
    if (c->object.flags & (SHOWN | BOUNDARY))
      continue;
    c->object.flags |= BOUNDARY;
    commit_list_insert(c, &revs->commits);
  }

  /*
   * If revs->topo_order is set, sort the boundary commits
   * in topological order
   */
  sort_in_topological_order(&revs->commits, revs->sort_order);
}

static struct commit *get_revision_internal(struct rev_info *revs)
{
  struct commit *c = NULL;
  struct commit_list *l;

  if (revs->boundary == 2) {
    /*
     * All of the normal commits have already been returned,
     * and we are now returning boundary commits.
     * create_boundary_commit_list() has populated
     * revs->commits with the remaining commits to return.
     */
    c = pop_commit(&revs->commits);
    if (c)
      c->object.flags |= SHOWN;
    return c;
  }

  /*
   * If our max_count counter has reached zero, then we are done. We
   * don't simply return NULL because we still might need to show
   * boundary commits. But we want to avoid calling get_revision_1, which
   * might do a considerable amount of work finding the next commit only
   * for us to throw it away.
   *
   * If it is non-zero, then either we don't have a max_count at all
   * (-1), or it is still counting, in which case we decrement.
   */
  if (revs->max_count) {
    c = get_revision_1(revs);
    if (c) {
      while (revs->skip_count > 0) {
        revs->skip_count--;
        c = get_revision_1(revs);
        if (!c)
          break;
        free_commit_buffer(revs->repo->parsed_objects, c);
      }
    }

    if (revs->max_count > 0)
      revs->max_count--;
  }

  if (c)
    c->object.flags |= SHOWN;

  if (!revs->boundary)
    return c;

  if (!c) {
    /*
     * get_revision_1() runs out the commits, and
     * we are done computing the boundaries.
     * switch to boundary commits output mode.
     */
    revs->boundary = 2;

    /*
     * Update revs->commits to contain the list of
     * boundary commits.
     */
    create_boundary_commit_list(revs);

    return get_revision_internal(revs);
  }

  /*
   * boundary commits are the commits that are parents of the
   * ones we got from get_revision_1() but they themselves are
   * not returned from get_revision_1().  Before returning
   * 'c', we need to mark its parents that they could be boundaries.
   */

  for (l = c->parents; l; l = l->next) {
    struct object *p;
    p = &(l->item->object);
    if (p->flags & (CHILD_SHOWN | SHOWN))
      continue;
    p->flags |= CHILD_SHOWN;
    gc_boundary(&revs->boundary_commits);
    add_object_array(p, NULL, &revs->boundary_commits);
  }

  return c;
}

struct commit *get_revision(struct rev_info *revs)
{
  struct commit *c;
  struct commit_list *reversed;

  if (revs->reverse) {
    reversed = NULL;
    while ((c = get_revision_internal(revs)))
      commit_list_insert(c, &reversed);
    free_commit_list(revs->commits);
    revs->commits = reversed;
    revs->reverse = 0;
    revs->reverse_output_stage = 1;
  }

  if (revs->reverse_output_stage) {
    c = pop_commit(&revs->commits);
    if (revs->track_linear)
      revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
    return c;
  }

  c = get_revision_internal(revs);
  if (c && revs->graph)
    graph_update(revs->graph, c);
  if (!c) {
    free_saved_parents(revs);
    free_commit_list(revs->previous_parents);
    revs->previous_parents = NULL;
  }
  return c;
}

const char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
{
  if (commit->object.flags & BOUNDARY)
    return "-";
  else if (commit->object.flags & UNINTERESTING)
    return "^";
  else if (commit->object.flags & PATCHSAME)
    return "=";
  else if (!revs || revs->left_right) {
    if (commit->object.flags & SYMMETRIC_LEFT)
      return "<";
    else
      return ">";
  } else if (revs->graph)
    return "*";
  else if (revs->cherry_mark)
    return "+";
  return "";
}

void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
{
  const char *mark = get_revision_mark(revs, commit);
  if (!strlen(mark))
    return;
  fputs(mark, stdout);
  putchar(' ');
}

Coverage Report

Created: 2026-01-09 07:10