Function have_duplicate_entry

builtin/pack-objects.c:1536–1556

* When adding an object, check whether we have already added it * to our packing list. If so, we can skip. However, if we are * being asked to excludei t, but the previous mention was to include * it, make sure to adjust its flags and tweak our numbers accordingly. * * As an optimization, we pass out the index position where we would have * found the item, since that saves us from having to

 * few lines later when we want to add the new entry.
 */
static int have_duplicate_entry(const struct object_id *oid,
				int exclude)
{
	struct object_entry *entry;

	if (reuse_packfile_bitmap &&
	    bitmap_walk_contains(bitmap_git, reuse_packfile_bitmap, oid))
		return 1;

	entry = packlist_find(&to_pack, oid);
	if (!entry)
		return 0;

	if (exclude) {
		if (!entry->preferred_base)
			nr_result--;
		entry->preferred_base = 1;
	}

	return 1;
}

static int want_cruft_object_mtime(struct repository *r,
				   const struct object_id *oid,