[Nix-dev] Haskellng - enable profiling

[Andreas Herrmann]

I just had the same problem. I have no idea whether it's the right way to do it, but I got it working in the following way:

Assuming that your package description is in `default.nix` (as created by cabal2nix) add the following two files to the same directory:

mypackage.nix:
 |  { profiling ? false }:
 |  
 |  with (import <nixpkgs> {}).pkgs;
 |  
 |  let
 |    mypackage = haskellngPackages.callPackage ./. {};
 |  in
 |  
 |  if profiling
 |  then mypackage.overrideScope (self: super: {
 |         inherit stdenv;  # Why this line is required is beyond me. =/
 |         mkDerivation = drv: super.mkDerivation (drv // { enableLibraryProfiling = true; });
 |       })
 |  else mypackage

shell.nix:
 |  { profiling ? false }:
 |  
 |  with (import <nixpkgs> {}).pkgs;
 |  with (import <nixpkgs/pkgs/development/haskell-modules/lib.nix> { inherit pkgs; });
 |  
 |  (overrideCabal (import ./mypackage.nix { inherit profiling; }) (drv: {
 |    buildTools = with haskellngPackages; [ cabal-install ghc-mod yesod-bin ];
 |  })).env

Now you can build your package with

    nix-build --arg profiling true mypackage.nix

And you can open a nix-shell with

    nix-shell --arg profiling true

I hope this helps.

Best, Andreas


On Monday 02 March 2015 00:25:26 Carlo Nucera wrote:
> Hi all, I'd like some help to build a haskell package I'm developing
> while transitively enabling profiling.  I'm trying to do the thing
> described in
> http://lists.science.uu.nl/pipermail/nix-dev/2015-January/015620.html
> What I'd like here is a demonstration on how to do that directly in
> the definition on myPackage (see below).
> 
> Here is, more or less, my .nixpkgs/config.nix:
> 
> |  { pkgs }: {
> |    allowBroken = true;
> |    allowUnfree = true;
> |
> |    haskellPackageOverrides = self: super: {
> |      ghci-ng   = self.callPackage /path/to/ghci-ng/default.nix   {};
> |      myPackage = self.callPackage /path/to/myPackage/default.nix {};
> |    };
> |
> |    packageOverrides = pkgs: with pkgs; rec {
> |
> |      haskellEnv = haskellngPackages.ghcWithPackages cabalPackages;
> |
> |      cabalPackages = hp: with hp; [
> |        cabal2nix
> |        cabal-install-bundle
> |        # Other libraries
> |
> |        myPackage
> |      ];
> |    };
> |  }
> 
> The goal here is to build myPackage with profiling enabled
> (transitively for his dependencies). If you have other advises on this
> file, feel free to share.
> 
> Thanks
> Carlo
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