decompress() will truncate any part of the filename after the first period, as it assumes it's part of the extension. For example, if your PharData archive is named "views-3.x-3.13.tar.gz", calling decompress on it will create a tar file named "views-3.tar". See https://bugs.php.net/bug.php?id=58852