<?php
    $tmp_file = tempnam(sys_get_temp_dir(), '');
    var_dump(is_file($tmp_file)); // returns true

    $zip = new ZipArchive;
    $zip->open($tmp_file, ZipArchive::OVERWRITE);
    $zip->close(); // returns true

    var_dump(is_file($tmp_file)); // returns true
    var_dump(file_get_contents($tmp_file)); // returns error file does not exist