[Nix-dev] The Future of Haskell Packaging in Nix

[Peter Simons]

Fellow Nixers and Haskellers,

the Haskell NG effort [1] allowed us for the first time to distribute the
latest version of every package known to Hackage -- well over 8,000 builds
in total --, and this seemed like a crazy leap forward at the time. These
days, we distribute 60+ Haskell package sets [2] that represent different
views into Hackage built with 8+ different compilers, and there's probably a
lot more variety out there, living in our user's `config.nix` files, that we
don't even know about. The requirements on our Haskell infrastructure become
ever more complex. New questions pop up due to the growing popularity of
Stack; our support for old compiler versions is somewhat lacking; and we
still don't have convincing answers to questions like: how do I compile my
package with profiling support?

The issues we have to address are mostly known and understood. What we lack
are brilliant ideas how to solve them.

This thread is an attempt to make some headway towards that end through open
discussion and collaboration. Instead of everyone having to browse a couple
of thousand Github tickets to find out what's going on, I'll regularly pick
one particular aspect that needs improvement and post a short article
outlining the issues we have and potential solutions that we know of so that
constructive dialogue can ensue.

Everyone is invited to participate in the conversation with ideas,
questions, suggestions, or references to Github Pull Requests that implement
a perfect, production-ready solution waiting to be merged.

Best regards,
Peter


[1] https://github.com/NixOS/nixpkgs/commit/c0c82ea2ebbcf0632260a931cf832cac1c8a014e
[2] https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/haskell-packages.nix