[Nix-dev] Build dependent haskell packages

[Peter Simons]

Hi,

 >   nix-env -qas -A nixos.pkgs.haskellPackages.xmonad
 >   IP-  haskell-xmonad-ghc7.8.3-0.12-shared

what version of NixOS do you use? The "ghc7.8.3-0.12-shared" bit of the
package name suggests it's something rather old.

 >   {
 >     packageOverrides = pkgs: rec {
 >       haskellPackages = with pkgs.haskellPackages; pkgs.haskellPackages // rec {
 >           xmonad = callPackage /home/lewo/repos/xmonad {};
 >           xmonadContrib = callPackage /home/lewo/repos/XMonadContrib {};
 >       };
 >     };
 >   }

That override won't work (evidently). It replaces the value of xmonad
that you see during "nix-env", but it won't replace the value of xmonad
that xmonadContrib sees while binding its dependencies. The Nixpkgs
manual covers these details in [1], but it refers to release-15.09 or
later of Nixpkgs, I'm afraid.

Best regards,
Peter

[1] http://nixos.org/nixpkgs/manual/#how-to-create-nix-builds-for-your-own-private-haskell-packages