The right thing would be to remove the possibility of removing a package so that the registry doesn't break.

That's on the global level. On a local level, everybody happily depending on a third-party network service in their build process (even if it is just for setting the environment up) makes an idiocy.

Linux distributions have this problem solved for more than two decades: put all the dependencies in a source package and compile from there. But no, it's an old solution, and the one from sysadmins' world, so it's not sexy and can't be possibly a valid approach.