I'm retiring from Haskell maintenance in Nixpkgs

Fellow Haskell ∩ Nix Hackers,

I would like to announce my retirement from maintaining the Haskell package set for Nix. The upcoming Twitch Livestream on Friday, 2021-04-30 20:00 UTC+2 will be my last merge of haskell-updates into master for the foreseeable future.

I have worried about the state of Haskell packaging for Nix in one way or another for almost 13 years. According to the git history, my earliest Haskell-related contribution was committed on 2008-07-07 – and there were some ~17,000 additional commits after that one. I think it’s fair to say that I have done my part for the cause and that I can now lean back and leave the mess I created for other people to clean up. :slight_smile:

Now, what does this all mean in practice? I have not stopped using Haskell and I haven’t stopped using Nix, so chances are that I’ll continue to contribute fixes and changes every now and then, but I will no longer …

  • update the hackage-packages.nix package set,
  • update the various ghc compilers,
  • fix up and merge the haskell-updates branch in a weekly livestream,
  • develop new features for cabal2nix or hackage2nix.

I have a bit of infrastructure set up that pushes daily updates from Hackage into the haskell-updates branch. I suppose I can leave those cron jobs running for a while if that’s helpful in any way, but ultimately I’d like to disable those jobs, too. Running hackage2nix is pretty trivial – there is no black magic involved in any of those things.

I have spent a lot of time writing cabal2nix et al and I intend do further maintenance for those tools. So if anyone happens to run into a problem or feels like they have discovered a bug, please don’t hesitate to let me know. I’ll do what I can to fix those issues. I just don’t see myself implementing any crazy new features.

Obviously, I’m feeling melancholic about leaving this part of my life behind. I had a lot of fun hacking Nix for the greater good of the Haskell ecosystem and I’ve got to know quite a few people in the process that I’ve enjoyed meeting. This is particularly true for the weekly livestream that I took up about 2 years ago. I would have never guessed that anyone would care to watch me ranting, raving, and cursing all the while I’m fixing obscure build errors. But against all odds, we’ve managed to build a small community of Hackers who, together, have managed the majority of this whole Haskell-packaging effort. I had a blast hanging out with you guys! My favorite livestream ever was the one where we had to define truth so that webkit could compile. I also very fondly remember racing my brand-new desktop machine against Rickard’s nixbuild.net to see who could re-compile the Haskell package set faster. It was great! :slight_smile:

So, thanks for the ride everyone! I’m sure this whole effort will go forward without me and I’m also pretty sure that it’s going to work just as well or even better than ever before.

Take care,


Many Haskellers are using Nix nowadays, and a large part is thanks to you and your dedication to creating a working Haskell package ecosystem. Thanks for all the work that you did!


About five years ago, I was struggling to distribute a hobby Haskell
project depending on a native library. I ranted about that on IRC,
someone suggested I should try this NixOS thingie hackage often listed
in the “Distributions” category.

Five years later, I use NixOS on about all my machines (going from
work-related deployments to my home router), maintain a fair share of
pkgs and modules, got commit access on nixpkgs, and met a lot of friends
from this online community along the way.

Contributing to Nix changed my vision about writing software. Not only
it made me a better sysadmin but also a better programmer by forcing me
to explore some upstream software I would never even think to read :slight_smile:

Your work acted as a gateway drug to a whole new universe for me.

I know from a fact I’m not an isolated case, your work sucked a fair
share of young Haskell hackers into Nix, gradually transforming them into
well-rounded engineers.

Thanks for all the fish Peter, I wish you all the best for what’s
coming next in your life :slight_smile:


Can only second this, peti single-handedly made nix blow up into what it is today by his haskellPackages work.


Thank you @peti for all of your amazing work, :slight_smile: . I first heard about nix through the reddit forum and it’s ability to solve “cabal hell”, when it was still a thing.


We’re really going to miss you @peti!

I definitely wouldn’t have gotten as involved in Nixpkgs if it weren’t for all the work you did on the Haskell infrastructure. You really got Nix and Haskell to a point where it is reasonable to use them for projects in a professional setting. I think it is quite extraordinary taking two niche technologies to that point!

You were also the one that pushed for me to get commit rights in Nixpkgs. I hope I was able to take off some of the burden for the Haskell-related PRs from you :slight_smile:

Also, someone should really point-out that there are over 1500 merged/closed PRs with the haskell tag on GitHub. That’s just insane, and really due to all the work peti put into to make the Haskell stuff usable:



Sounds like your brainchild has grown up and is moving out :slight_smile: You did a great job raising it. Thank you @peti!


Haskell is also how I got into Nix. Thanks for all your hard work, @peti!


Sad to see you go, thanks for all the hard work and the streams I occasionally joined and enjoyed very much!


Goodbye, good luck and godspeed @peti . We didn’t do a lot of work together, but you merged a few of my haskell/nixpkgs PRs, and I appreciate the work you’ve done and the patience you showed me while I was learning the ropes.

Do you have succession plans for the nixpkgs/haskell infrastructure?


Thank you very much for the vision and all the work on it over the years @peti! Will be interesting to see what you do next. :+1:

Thanks Peti for all your work on the Haskell infrastructure, and for your seemingly infinite stamina of reporting issues and submitting fixes upstream!

Your work has significant impact, as it kickstarted the use of Nix in many Haskell projects, and also in multiple companies.


Thank you for your instrumental work. I am using Nix and Haskell today both professionally and on my personal time. I certainly would not have been able to do so without your persistence in making pkgs.haskellPackages such a great tool.


Thank you very much for what you have done for the community on the NixOS side! You might not remember, but I had the great pleasure to meet you at NixCon 2015 and I know that you’re a very nice person to work with and you were always a great inspiration to me, even though I only met you for two days and I am not even a Haskeller :smiley:

PS: I love the cat facts on your website!

Same here, the Haskell infrastructure of Nixpkgs was my gateway into Nix. Thank you very much for all your hard work @peti!

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