Function reset_tree

builtin/checkout.c:754–794

}

static int reset_tree(struct tree *tree, const struct checkout_opts *o,
		      int worktree, int *writeout_error,
		      struct branch_info *info)
{
	struct unpack_trees_options opts;
	struct tree_desc tree_desc;

	memset(&opts, 0, sizeof(opts));
	opts.head_idx = -1;
	opts.update = worktree;
	opts.skip_unmerged = !worktree;
	opts.reset = o->force ? UNPACK_RESET_OVERWRITE_UNTRACKED :
				UNPACK_RESET_PROTECT_UNTRACKED;
	opts.preserve_ignored = (!o->force && !o->overwrite_ignore);
	opts.merge = 1;
	opts.fn = oneway_merge;
	opts.verbose_update = o->show_progress;
	opts.src_index = the_repository->index;
	opts.dst_index = the_repository->index;
	init_checkout_metadata(&opts.meta, info->refname,
			       info->commit ? &info->commit->object.oid : null_oid(the_hash_algo),
			       NULL);
	if (repo_parse_tree(the_repository, tree) < 0)
		return 128;
	init_tree_desc(&tree_desc, &tree->object.oid, tree->buffer, tree->size);
	switch (unpack_trees(1, &tree_desc, &opts)) {
	case -2:
		*writeout_error = 1;
		/*
		 * We return 0 nevertheless, as the index is all right
		 * and more importantly we have made best efforts to
		 * update paths in the work tree, and we cannot revert
		 * them.
		 */
		/* fallthrough */
	case 0:
		return 0;
	default:
		return 128;
	}
}

static void setup_branch_path(struct branch_info *branch)
{