In this post I wish to explain a bit about Perl related ebuilds in Gentoo and how to update from perl-core to virtual/perl without conflicts.
First of all the core distribution of Perl is included in dev-lang/Perl along with modules.
The perl-core category in portage contains ebuilds for perl modules, some of which are included in the core perl distibution. The perl-core ebuilds overrides the perl-core modules such that you can update them without recompiling dev-lang/Perl.
Each perl-core module has a corrensponding virtual/perl-* package. The virtual category is used by portage when emerging to take into account that a module can be either provided by dev-lang/perl package or found in perl-core category.
So, what to do in case of blocks when upgrading your Gentoo machine?
Perl-cleaner is a package provided to get rid of these blocks and to migrate from perl-core to virtual/perl-*.
emerge perl-cleaner emerge dev-lang/perl perl-cleaner --all
if you still have problems when upgrading @world you add a backtrack option
emerge -uDN --backtrack=30 @world
or you can unmerge all perl-core packages and then finally upgrade world
emerge --unmerge perl-core/*
This will remove all perl-core packages that virtual/perl-* packages will bring back if needed.
Francesco Mecca