hackage2nix

hackage2nix

This tool is used to update the Haskell package set in nixpkgs (hackage-packages.nix).

Most of the time we do not need run this manually (since it is run automatically on the upstream nixpkgs). Exceptions:

• To update the Haskell package set in nixpkgs.

• To test that a structural change to nixpkgs (e.g. name change of a system package) does not break Haskell packages.

• To test changes to hackage2nix itself.

Video tutorial

There is a video on YouTube that gives a thorough walk-through of these steps.

It also explains many of the background considerations.

Requirements

This must be run on a case sensitive file system. On OSX you can use this to create one (you can replace 60g with 4g as that should be plenty).

Setup

This shows the setup that nixpkgs Haskell maintainers use to iterate on both cabal2nix, hackage2nix, and the Haskell package set in nixpkgs.

It clones cabal2nix and puts a nixpkgs checkout into it, which the repo's update-nixpkgs.sh script will update for you.

Replace [email protected]:NixOS/nixpkgs.git with a fork you have push access to.

git clone https://github.com/NixOS/cabal2nix.git
cd cabal2nix
git clone [email protected]:NixOS/nixpkgs.git # replace this with your fork
git clone https://github.com/commercialhaskell/all-cabal-hashes.git --branch hackage hackage
# For high reproducibility and pinned nixpkgs for native dependencies
# (you can leave `--nix` off on NixOS, or if you don't have nix installed):
stack --nix build
# Alternatively, to use Cabal's resolver:
cabal install

Running hackage2nix

Runs hackage2nix and pushes a commit with the updated hackage-packages.nix file to your fork of nixpkgs.

./update-nixpkgs.sh