Question

基本上我在用这个：

default.nix

{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc864" }:
nixpkgs.pkgs.haskell.packages.${compiler}.callPackage ./gitchapter.nix { }

gitchapter.nix

{ mkDerivation, base, directory, extra, filepath, foldl, hpack
, HUnit, mtl, optparse-applicative, pandoc-include-code, parsec
, pretty-simple, process, QuickCheck, rainbow, regex-pcre
, regex-posix, safe, stdenv, string-conversions, system-filepath
, template-haskell, text, transformers, turtle, unix
, unordered-containers
}:
mkDerivation {
  pname = "gitchapter";
  version = "0.1.0.0";
  src = ./.;
  isLibrary = false;
  isExecutable = true;
  libraryToolDepends = [ hpack ];
  executableHaskellDepends = [
    base directory extra filepath foldl HUnit mtl optparse-applicative
    pandoc-include-code parsec pretty-simple process QuickCheck rainbow
    regex-pcre regex-posix safe string-conversions system-filepath
    template-haskell text transformers turtle unix unordered-containers
  ];
  preConfigure = "hpack";
  license = stdenv.lib.licenses.bsd3;
}

但是pandoc-include-code却有一个无法构建的问题，此问题似乎已经在git存储库中修复。如何覆盖该软件包以指向git存储库或本地目录？

我会按照https://nixos.org/nixos/nix-pills/nixpkgs-overriding-packages.html上的说明进行操作吗，还是由于使用nixpkgs.pkgs.haskell.packages.${compiler}.callPackage函数而使工作原理有所不同？

编辑： 感谢@sara的回答，我现在有了：

{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc864" } :
let
  gitchapter = nixpkgs.pkgs.haskell.packages.${compiler}.callCabal2nix "gitchaper" (./.) {};
  zzzzz = nixpkgs.pkgs.haskell.lib.overrideCabal gitchapter;
in
  nixpkgs.pkgs.haskell.packages.${compiler}.callPackage (zzzzz) { }

所以我想现在是确定现在如何覆盖该依赖关系的问题。

Answer 1

考虑使用callCabal2nix中的haskell.packages.${compiler}！

它将遍历您的.cabal文件，并为该文件派生一个nix表达式（因此无需使用gitchapter.nix），然后您可以使用overrideCabal中的haskell.lib函数覆盖它与常规推导覆盖类似的方式。然后，您可以从git中获取更新的pandoc派生版本，并将其作为buildInput添加到您的覆盖表达式中。

Answer 2

我将要覆盖的存储库克隆到pandoc-include-code/中，然后：

{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc864" } :
let
  myHaskellPackages = nixpkgs.pkgs.haskell.packages.${compiler}.override {
    overrides = self: super: rec {
    pandoc-include-code  = self.callCabal2nix "pandoc-include-code" (./pandoc-include-code) {};
    };
  };
in
  myHaskellPackages.callCabal2nix "gitchaper" (./.) {}

要直接引用git存储库：

{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc864" } :
let
  myHaskellPackages = nixpkgs.pkgs.haskell.packages.${compiler}.override {
    overrides = self: super: rec {
    pandoc-include-code  = self.callCabal2nix "pandoc-include-code" (builtins.fetchGit {
        url = "git@github.com:owickstrom/pandoc-include-code.git";
        rev = "3afe94299b3a473fda0c62fdfd318435117751dd";
      })
      {};
    };
  };
in
  myHaskellPackages.callCabal2nix "gitchaper" (./.) {}

使用callPackage时，如何使用Nix用git / local包覆盖Haskell包？

2 个答案: