Using app-portage/g-cpan-0.15.0-r1 from the core tree and dev-lang/perl-5.10.0-r2 from perl-experimental, ebuilds that do not install any content are now created. The problem is that Gentoo::CPAN assigns to ${S} using $CPAN::Distribution::build_dir, which under the split CPAN package in 5.10 uses File::Temp::tempdir and includes additional unique '-XXXX' data after the package's name. The results are thus: S=${WORKDIR}/JE-0.033-LujY1a as opposed to the expected: S=${WORKDIR}/JE-0.033 This causes the perl-module eclass to fail, since extraction doesn't replicate the same directory naming structure.
Initially added this to the 5.10 tracker, but somehow that got lost in the original save.
Should be fixed in g-cpan r226, will be released soon.
Confirmed. Thanks for taking up maintenance of g-cpan and fixing these several bugs!