|Subject:||Don't allow *.ppm.zip as a valid distribution name|
There are a couple of files on CPAN with a ".ppm.zip" extension (e.g. Class-Prototyped-1.11.ppm.zip. Because these have a .zip extension and because ppm format is just a zip archive, it's possible for CPAN to attempt to extract it and make/test/install. In the latest dev releases, it will fail during extraction because it looks like a poorly formed distribution, but it would probably be better to identify a request for .ppm.zip and reject with a more helpful error message.