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](https://packages.gentoo.org/package/dev-lang/perl) along with [modules](http://perldoc.perl.org/index-modules-A.html). The [perl-core category](https://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/perl-core/) 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