@peti As you can probably tell from the error, I'm making these changes blindly.

Can you teach me how to go all the way from building cabal2nix to running whatever Hydra does?

@nh2, are you aware of the update-nixpkgs.sh script in the cabal2nix repo?

@peti No, I haven't used any of that stuff yet. Is that the one I should use?

@nh2, that is the script that's running once per night to update the haskell-updates branch. So if you'd like to know how to run hackage2nix to re-generate the entire haskell-packages.nix file, then that's a pretty good source of information.