Remove cross-installed packages

When I started my new job back in 2016 I needed to install Skype on my workstation. As you can imagine my workstation uses Exherbo. Consequently, it was necessary to build all dependencies using i686 architecture to be able to install the old Skype client¹.

I enabled i686 with the paludis target i686-pc-linux-gnu and began to recompile a lot of packages. But things didn't go well and in the end, I was unable to use the client. I ended up using a container just for this software.

But in the meantime some cross-compiled packages altered the system: some x86_64 files were replaced by their i686 counterparts and some alternatives were broken. It was time to try to cleanup things.

First of all, we need to ignore some packages which are installed by default on both targets. Save the following lines in a file named ignore:

sys-kernel/linux-headers
sys-libs/glibc
sys-libs/libatomic
sys-libs/libgcc
sys-libs/libstdc++

Then, we need to reinstall all cross-compiled packages in the main target (::installed or x86_64 here) to touch colliding files:

cave resolve $(cave print-ids -m '*/*::i686-pc-linux-gnu' -f '%c/%p ') -x1 -Cs

Now that colliding files has been touched by ::installed packages we can uninstall all packages from i686-pc-linux-gnu except the system ones:

cave print-ids -m '*/*::i686-pc-linux-gnu' -f '=%c/%p-%v::i686-pc-linux-gnu\n' | \
grep -v -F -f ignore | head -n25 | \
xargs cave uninstall -Cs -mx -u '*/*' -u system -x1

Colliding files will remain untouched because the uninstalled packages don't own them anymore thanks to the previous cave resolve.

Finally we must check the alternatives and revive broken ones:

find /etc/env.d/alternatives/ -type d -mindepth 1 -maxdepth 1 '!' -exec test -e "{}/_current" ';' -print

This command will print all broken symlinks found in the directory /etc/env.d/alternatives.

Revive the broken alternatives using eclectic alternatives update, e.g. with systemd:

eclectic alternatives update init systemd

Thanks to @sardemff7 who helped me going through this mess.

Enjoy!