| 3 Jul 2025 |
 woobilicious | brillant it worked, only issue was tests failing due to missing asset files, disabled tests and imports are working | 17:37:26 |
|  syd installs gentoo (they/them) joined the room. | 18:46:50 |
| syd installs gentoo (they/them) | Hey there! I hope some questions are appreciated. I'm trying to bump nix-tree (after asking the developer a while back to bump in hackage https://github.com/utdemir/nix-tree/issues/114#issuecomment-2888634183 ) assuming it would get updated eventually by nixos maintainers and the file says that you should use the regenerate-hackage-packages.sh but that fails on my local machine - I'd like to get in touch with the people maintaining that and assumed there was a Haskell Matrix channel maybe (there aren't a lot of GitHub issues around Hackage/Haskell lately if I'm not mistaken). | 18:51:28 |
| syd installs gentoo (they/them) | ➜ nixpkgs git:(master) ✗ ./maintainers/scripts/haskell/regenerate-hackage-packages.sh --do-commit
Obtaining Hackage data
Generating compiler configuration
Starting hackage2nix to regenerate pkgs/development/haskell-modules/hackage-packages.nix ...
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/webdriver-precore/0.1.0.2/webdriver-precore.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/ulid/0.3.3.0/ulid.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/tpdb/2.8.1/tpdb.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/singletons-base-code-generator/0.1/singletons-base-code-generator.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/singletons-base/3.5/singletons-base.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pty-mcp-server/0.0.4.0/pty-mcp-server.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-ui-response/0.0.3.0/pms-ui-response.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-ui-request/0.0.3.0/pms-ui-request.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-ui-notification/0.0.2.0/pms-ui-notification.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-infrastructure/0.0.4.0/pms-infrastructure.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-infra-watch/0.0.2.0/pms-infra-watch.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-infra-procspawn/0.0.1.0/pms-infra-procspawn.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-infra-cmdrun/0.0.2.0/pms-infra-cmdrun.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-domain-service/0.0.3.0/pms-domain-service.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-domain-model/0.0.4.0/pms-domain-model.cabal)
hackage2nix: user error (cannot parse cabal file /nix/store/pv9625kwkhfj0bsgqc374by44ycm88cz-unpacked-cabal-hashes/pms-application-service/0.0.4.0/pms-application-service.cabal)
hackage2nix: thread blocked indefinitely in an MVar operation
| 18:51:46 |
| syd installs gentoo (they/them) | Reading the history of this channel I can see others also ran into thread blocked indefinitely in an MVar operation. I'm not sure if it the script is fully needed getting nix-tree usable again for others :). | 18:53:34 |
| syd installs gentoo (they/them) | https://github.com/NixOS/nixpkgs/issues/409085
ah I didn't get follow up github notifications.
https://github.com/NixOS/nixpkgs/pull/409117#issuecomment-2895401376 | 18:55:05 |
| syd installs gentoo (they/them) | Well at least I gave updating hackage packages a try for once, good to learn how that is done under the hood. | 18:57:00 |
| syd installs gentoo (they/them) | * Hey there! I've had some questions, I understand the situation now...
Old message/thread:
I'm trying to bump nix-tree (after asking the developer a while back to bump in hackage https://github.com/utdemir/nix-tree/issues/114#issuecomment-2888634183 ) assuming it would get updated eventually by nixos maintainers and the file says that you should use the regenerate-hackage-packages.sh but that fails on my local machine - I'd like to get in touch with the people maintaining that and assumed there was a Haskell Matrix channel maybe (there aren't a lot of GitHub issues around Hackage/Haskell lately if I'm not mistaken). | 19:00:25 |
 teo (they/he) | I was profiling eval time of nixpkgs recently and I noticed that a lot of time was spent doing hasPrefix when evalling the haskell package set. I think this is caused by the hasPrefix call to check if stuff is part of amazonka and each call of hasPrefix re-checks if the needle is a path lol https://github.com/NixOS/nixpkgs/issues/419216
We could optimise the hasPrefix call, but maybe we should just add the list of amazonka packages to this file rather than traversing the entire haskell package set?
https://github.com/NixOS/nixpkgs/blob/a44903b927ab16b829a76f51f84bca02a7f89a0f/pkgs/development/haskell-modules/configuration-common.nix#L3352 | 19:19:35 |
 alexfmpe |
I was profiling eval time of nixpkgs
how does one even do this? I always wondered
| 20:24:38 |
| teo (they/he) | In reply to @alexfmpe:matrix.org
I was profiling eval time of nixpkgs
how does one even do this? I always wondered
This is what I used https://github.com/NixOS/nix/pull/13220 | 20:30:51 |
| alexfmpe | Ooooh | 20:37:45 |
| 4 Jul 2025 |
 lxsameer | hey folks,do we support cabal 3.14 for development? | 15:16:38 |
| alexfmpe | not sure what "for development" means, does this answer it?
$ nix-build -A cabal-install
/nix/store/diig4i6ln0ia8xvv4kqs99klpjhlpzfl-cabal-install-3.14.2.0
| 15:38:44 |
| lxsameer | sorry for the confusion, apparently, cabal2nix does not like the cabal-version: 3.14 | 15:51:24 |
| lxsameer | in a cabal file | 15:51:28 |
 maralorn | That was I think fixed very recently on the haskell-updates. | 15:52:48 |
 ners | I found a package that has outdated dependency bounds. Trying to build it with doJailbreak , I would expect it to either succeed or fail at compile time, but:
Configuring OTP-0.1.0.0...
CallStack (from HasCallStack):
withMetadata, called at libraries/Cabal/Cabal/src/Distribution/Simple/Utils.hs:368:14 in Cabal-3.10.3.0-ab3d:Distribution.Simple.Utils
Error: Setup: Encountered missing or private dependencies:
base >=4.5.0.0 && <4.14,
bytestring >=0.9.2.0 && <0.11,
time >=1.4 && <1.10
| 16:40:27 |
| alexfmpe | cabal2nix doesn't handle conditionals properly (for now), and the deps are behind a if, so they don't survive the conversion to .nix | 17:01:15 |
| alexfmpe | https://hackage.haskell.org/package/OTP-0.1.0.0/src/OTP.cabal | 17:01:16 |
| alexfmpe | You can workaround by shoving them in with addBuildDepends | 17:01:41 |
| alexfmpe | You can see examples in the configuration-ghcjs-9.x and configuration-darwin files | 17:02:26 |
 Collin Arnett | How can I get the haddoc html files for dependencies of my project when using shellFor? I have doHaddoc turned on for my dependencies. | 18:35:27 |
| alexfmpe | It's on by default I think? | 19:35:28 |
| alexfmpe | Easiest way is to run hoogle locally | 19:35:41 |
| alexfmpe | hoogle server --local -p 8080 | 19:36:18 |
| alexfmpe | might need withHoogle = true, don't remember if default in shellFor | 19:36:48 |
| Collin Arnett | Does the hoogle server serve the haddocs as well? I'm not really sure what I'm looking for so I would like to browse the docs like I would on hackage. | 20:44:03 |
| Collin Arnett | Oh I see it does link them locally after you click on the package from hoogle. Thank you :D | 20:49:02 |
| 5 Jul 2025 |
| alexfmpe | is there a way for a nixpkgs-using project to apply an override to all haskell.packages.ghc123 like configuration-common.nix do?
or do we always need the nixpkgs.haskell.packages.${version} override cascade ? | 20:20:02 |
