TIL: How to Fix Package Binary Collisions on Nix

Recently I wanted to use GNU parallel, a nifty little tool we can use to run tasks in parallel, shock horror I know. I already have the moreutils package installed using nix (home-manager).

So I added this:

home.packages = with pkgs; [

Then I ran the home manager switch like usual, I got the following error.

error: builder for '/nix/store/vh6i81xhf6pvybdpall8z8l8y0i6mr8p-home-manager-path.drv' failed with exit code 25;
       last 1 log lines:
       > error: collision between `/nix/store/slkylri9sbn4w7paaixzc5wj6cwfk83m-moreutils-0.67/bin/parallel' and `/nix/store/fjpnw99zvx2f910s016jrmybc5jxirpn-parallel-20230822/bin/parallel'
       For full logs, run 'nix log /nix/store/vh6i81xhf6pvybdpall8z8l8y0i6mr8p-home-manager-path.drv'.
error: 1 dependencies of derivation '/nix/store/m4p56x5lgjfpvdy0xjrbk981sfchpl8c-home-manager-generation.drv' failed to build

Because moreutils also have a binary called parallel. How do we tell Nix to overwrite the moreutils binary and use the one in the parallel packages? Simple by using lib.hiPrio like so:

home.packages = with pkgs; [
  (lib.hiPrio parallel)

This tells Nix to increase the priority of this package you can see the code here.

That’s it we can still have access to the other binaries moreutils provides like sponge and parallel from parallel package.