I did a bit more digging and I think I've found the issue. I'm doing mixed development. That is to say that I'm developing on both a Linux and a Windows machine. I had originally generated the MANIFEST.SKIP file on the Windows machine, but was seeing the above mentioned behavior on the Linux machine. For whatever reason, the light bulb flashed: line endings. I've confirmed that this is the case: running my MANIFEST.SKIP file through perl -i -ple 's/^M//' MANIFEST.SKIP
and re-generating the MANIFEST gives the desired results. I think I'll send an e-mail to the Module::Build
folks and see what they say. In the interim though, problem solved!
The only easy day was yesterday