void verify_non_filename(const char *prefix, const char *arg)
{
	const char *name;
	struct stat st;

	if (!is_inside_work_tree() || is_inside_git_dir())
		return;
	if (*arg == '-')
		return; /* flag */
	name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
	if (!lstat(name, &st))
		die("ambiguous argument '%s': both revision and filename\n"
		    "Use '--' to separate filenames from revisions", arg);
	if (errno != ENOENT && errno != ENOTDIR)
		die("'%s': %s", arg, strerror(errno));
}
Unknown