!RbXGJhHMsnQcNIDFWN:nixos.org

Haskell in Nixpkgs/NixOS

691 Members
For discussions and questions about Haskell with Nix, cabal2nix and haskellPackages in nixpkgs | Current Docs: https://haskell4nix.readthedocs.io/138 Servers

Load older messages

SenderMessageTime
19 Oct 2025
@raboof:matrix.orgraboofI noticed that we're packaging both .so and .a artifacts where Arch seems to only include the .so . Probably a naive question, but are we using those .a's? :)16:40:29
@raboof:matrix.orgraboof with https://github.com/NixOS/nixpkgs/commit/fffebd7398360d241c3e34f01af4813ef199e488 haskell.packages.ghc912.these seems deterministic, so that's promising! 17:03:16
@wolfgangwalther:matrix.orgWolfgang WaltherThat PR is just the regular update of haskellPackages. We track Stackage. Stackage LTS is currently on GHC 9.10.3. So when we upgrade to GHC 9.12 is mostly dependent on when Stackage updates. We just updated to GHC 9.10 recently, so it will still take a while. Ofc, we can enable this flag for GHC 9.12+ already - but we won't build the big majority of haskell packages with it, yet. And we won't have insights into whether it might cause build problems, because we don't build the full package set for GHC 9.12, yet.17:33:01
@raboof:matrix.orgraboofGotcha, makes sense17:56:09
@raboof:matrix.orgraboofit might be interesting to enable it by default for 9.12 - cache.nixos.org does appear to contain a bunch of packages.ghc912 packages (though it's not quite clear to me where they're built), so it might allow us to see build problems early20:18:58
20 Oct 2025
@peterbecich:matrix.orgPeter Becich

Would someone take a look at hls-cabal-plugin on NixPkgs?

Breakage reproducible on both master and haskell-updates:

NIXPKGS_ALLOW_BROKEN=1 nix build nixpkgs#haskellPackages.hls-cabal-plugin --impure 

NIXPKGS_ALLOW_BROKEN=1 nix build nixpkgs/haskell-updates#haskellPackages.hls-cabal-plugin --impure

I believe this is contributing to a breakage of Haskell Language Server

04:38:28
@maralorn:maralorn.demaralornNo, the standalone hls plugin packages are deprecated, they were moved into the hls package06:17:09
@peterbecich:matrix.orgPeter BecichThanks!06:19:50
@sternenseemann:systemli.orgsterni
In reply to @raboof:matrix.org
with https://github.com/NixOS/nixpkgs/commit/fffebd7398360d241c3e34f01af4813ef199e488 haskell.packages.ghc912.these seems deterministic, so that's promising!
did you measure performance impact 		06:59:59
@sternenseemann:systemli.orgsterni
In reply to @raboof:matrix.org
I noticed that we're packaging both .so and .a artifacts where Arch seems to only include the .so . Probably a naive question, but are we using those .a's? :)
yes 		07:00:18
@sternenseemann:systemli.orgsterni
In reply to @raboof:matrix.org
with https://github.com/NixOS/nixpkgs/commit/fffebd7398360d241c3e34f01af4813ef199e488 haskell.packages.ghc912.these seems deterministic, so that's promising!
* did you measure performance impact? 		07:00:28
@sternenseemann:systemli.orgsterni
In reply to @raboof:matrix.org
I noticed that we're packaging both .so and .a artifacts where Arch seems to only include the .so . Probably a naive question, but are we using those .a's? :)
* yes, dynamically linking executables means excessively large closure sizes 		07:01:25
@alex:tunstall.xyzAlex
In reply to @sternenseemann:systemli.org
yes
As usual, separate outputs would be nice but potentially require a lot of effort to implement. :s 		08:17:03
21 Oct 2025
@alexeusgr:matrix.org50^2 changed their profile picture.04:51:49
@le:4d2.org@le:4d2.org left the room.10:36:16
@eldritchcookie:matrix.orgeldritchcookieis cabal2nix not aware of build-tools-depends or do i need to blame flake-parts's haskell-flake?21:57:25
@artem.types:matrix.orgArtem eldritchcookie: the latter I think 23:13:21
@artem.types:matrix.orgArtem * eldritchcookie: the former I think 23:13:25
@artem.types:matrix.orgArtem * eldritchcookie: the former I think (not aware) 23:13:33
@eldritchcookie:matrix.orgeldritchcookiei did some digging and actually calling cabal2nix on my cabal package has an output which contains TestToolDepends = [tasty-discover]; so somebody is dropping that and it certainly isnt cabal2nix23:17:22
22 Oct 2025
@raboof:matrix.orgrabooffor 'these' it does seem slower, but in the order of 'tens of milliseconds' on an ~11-second build. I tried a more substantial package (hoogle), that was about 2 seconds slower for a 46-second build (averages across 4 builds each). So measurable impact (but promising to see it did seem to have the desired effect for hoogle as well)...10:39:44
@magic_rb:matrix.redalder.orgmagic_rb

hm, im getting this from nixpkgs:

       > [55 of 73] Compiling JavaScript.Web.Canvas.ImageData ( JavaScript/Web/Canvas/ImageData.hs, dist/build/JavaScript/Web/Canvas/ImageData.o )
       > [56 of 73] Compiling JavaScript.Web.Canvas ( JavaScript/Web/Canvas.hs, dist/build/JavaScript/Web/Canvas.o )ipt/Web/Canvas/Internal.o )
       > [57 of 73] Compiling JavaScript.Web.Canvas.TextMetrics ( JavaScript/Web/Canvas/TextMetrics.hs, dist/build/JavaScript/Web/Canvas/TextMetrics.o )
       > [58 of 73] Compiling JavaScript.Web.CloseEvent.Internal ( JavaScript/Web/CloseEvent/Internal.hs, dist/build/JavaScript/Web/CloseEvent/Internal.o )
       > [59 of 73] Compiling JavaScript.Web.CloseEvent ( JavaScript/Web/CloseEvent.hs, dist/build/JavaScript/Web/CloseEvent.o )ionFrame.o )
       > [60 of 73] Compiling JavaScript.Web.ErrorEvent.Internal ( JavaScript/Web/ErrorEvent/Internal.hs, dist/build/JavaScript/Web/ErrorEvent/Internal.o )
       > [61 of 73] Compiling JavaScript.Web.ErrorEvent ( JavaScript/Web/ErrorEvent.hs, dist/build/JavaScript/Web/ErrorEvent.o )
       > [62 of 73] Compiling JavaScript.Web.File ( JavaScript/Web/File.hs, dist/build/JavaScript/Web/File.o )1;
       > [63 of 73] Compiling JavaScript.Web.History ( JavaScript/Web/History.hs, dist/build/JavaScript/Web/History.o )
       > [64 of 73] Compiling JavaScript.Web.Location ( JavaScript/Web/Location.hs, dist/build/JavaScript/Web/Location.o )
       > [65 of 73] Compiling JavaScript.Web.MessageEvent.Internal ( JavaScript/Web/MessageEvent/Internal.hs, dist/build/JavaScript/Web/MessageEvent/Internal.o )
       > [66 of 73] Compiling JavaScript.Web.MessageEvent ( JavaScript/Web/MessageEvent.hs, dist/build/JavaScript/Web/MessageEvent.o )
       > [67 of 73] Compiling JavaScript.Web.Performance ( JavaScript/Web/Performance.hs, dist/build/JavaScript/Web/Performance.o )
       > [68 of 73] Compiling JavaScript.Web.Storage.Internal ( JavaScript/Web/Storage/Internal.hs, dist/build/JavaScript/Web/Storage/Internal.o )
       > [69 of 73] Compiling JavaScript.Web.Storage ( JavaScript/Web/Storage.hs, dist/build/JavaScript/Web/Storage.o )
       > [70 of 73] Compiling JavaScript.Web.StorageEvent ( JavaScript/Web/StorageEvent.hs, dist/build/JavaScript/Web/StorageEvent.o )
       > [71 of 73] Compiling JavaScript.Web.WebSocket ( JavaScript/Web/WebSocket.hs, dist/build/JavaScript/Web/WebSocket.o )
       > [72 of 73] Compiling JavaScript.Web.Worker ( JavaScript/Web/Worker.hs, dist/build/JavaScript/Web/Worker.o )
       > [73 of 73] Compiling JavaScript.Web.XMLHttpRequest ( JavaScript/Web/XMLHttpRequest.hs, dist/build/JavaScript/Web/XMLHttpRequest.o )
       > javascript-unknown-ghcjs-ghc-9.10.3: JavaScript C pre-processor: could not execute:
       For full logs, run:
         nix log /nix/store/b9y291nv2niv71aggzy6l5gnhvn6qkdx-ghcjs-base-0.8.0.4.drv
error: 1 dependencies of derivation '/nix/store/fpfwgskiyns3lbfa23b98mzmnknzvy0s-jsaddle-0.9.9.3.drv' failed to build
error: 1 dependencies of derivation '/nix/store/fwfk823qa6ghsxy3ba95k9a06ij4w4m5-miso-1.8.7.0.drv' failed to build

weird

20:24:03
@magic_rb:matrix.redalder.orgmagic_rbits an interesting failure, very, not helpful20:24:57
23 Oct 2025
@alexfmpe:matrix.orgalexfmpemight want to try 9.12 from recent nixpkgs17:23:06
@alexfmpe:matrix.orgalexfmpepkgsCross.ghcjs.haskell.packages.ghc912 has cached miso and reflex-dom, which means a lot of other packages are also cached by being their deps17:23:38
@alexfmpe:matrix.orgalexfmpe I get nix-build -A pkgsCross.ghcjs.haskell.packages.ghc912.ghcjs-base from cache on https://github.com/NixOS/nixpkgs/commit/c90b7f75f4e9d4dffcdc30261f565da1e261d468 which is just a few days old 17:26:32
@alexfmpe:matrix.orgalexfmpe magic_rb: ^ 17:26:42
@dandart:matrix.orgPeriI kind of gave up with ghcjs when it started giving cryptic errors so I moved my stack over to wasm17:27:18
@alexfmpe:matrix.orgalexfmpejs backend is recent enough I wouldn't bother much with anything older than 9.12 17:27:21
@alexfmpe:matrix.orgalexfmpebut yeah, wasm is very much an option17:27:59

Show newer messages

Back to Room ListRoom Version: 6