I currently have a Yesod web application that I am developing on NixOS. I am using a default.nix
file like described in O'Charles' blog post:
{ haskellPackages ? (import <nixpkgs> {}).haskellPackages }:
haskellPackages.cabal.mkDerivation (self: {
pname = "myblog";
version = "0.0.0";
src = ./.;
isLibrary = true;
isExecutable = true;
buildDepends = with haskellPackages; [
aeson bson conduit dataDefault fastLogger hjsmin
httpConduit monadControl monadLogger mongoDB persistent
#persistentMongoDB
persistentTemplate poolConduit shakespeare text
waiExtra waiLogger warp yaml yesod yesodAuth
yesodCore yesodDefault yesodForm yesodStatic
];
testDepends = with haskellPackages; [
hspec monadLogger persistent
#persistentMongoDB
resourcet transformers yesod yesodCore yesodTest
];
buildTools = with haskellPackages; [
cabalInstall ghcMod yesodBin
];
jailbreak = true;
})
This is working very well. I can use the yesod
binary and cabal
like normal. However, I am running into one problem. When running cabal haddock
, I am getting the following error:
Running Haddock for mycoolblog-0.0.0...
Preprocessing library mycoolblog-0.0.0...
Warning: The documentation for the following packages are not installed. No
links will be generated to these packages: persistent-mongoDB-2.1.1
<command line>: cannot satisfy -package-id aeson-0.8.0.2-9e93bdd6f8e68379314dd5f31414f87f
(use -v for more information)
Googling about this brings up the following link: github: cabal haddock 'cannot satisfy -package-id' #2468. It seems like it is saying that ghcWithPackages should be used.
Googling about ghcWithPackages
brings up O'Charles' (personal?) wiki on Nix. It has an example of using ghcWithPackages
to develop a package that is already in nixpkgs, but I can't get it to work with a package that is not already in nixpkgs (my cms/blog).
Setting it up like described on O'Charles' wiki and running nix-shell -v
, I get the following error:
evaluating file `/nix/store/an4sg7cxi1ii3vids8417kajl3ss13vd-nix-1.7/share/nix/corepkgs/derivation.nix'
error: cannot auto-call a function that has an argument without a default value (`cabal')
Why am I getting the above error? How can I write a default.nix
and shell.nix
for a Haskell project that's not already in nixpkgs? Ideally it would be using ghcWithPackages
so that cabal haddock
works.
I was able to get this working after using the method on O'Charles' Nix wiki. I have not determined why this method was not working before.
Basically, first run
cabal2nix
. Then create a generic shell.nix (that can be shared between all Haskell packages).