Poetry2nix Flake构建报错：`poetry2nix.overrides`属性缺失

基于poetry2nix官方应用模板编写flake.nix，仅修改overrides部分，执行nix build命令时报错，提示poetry2nix.overrides属性缺失。

我的flake代码 #

{
  description =  "bear";

  inputs = {
    flake-utils.url = "github:numtide/flake-utils";
    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
    poetry2nix = {
      url = "github:nix-community/poetry2nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, flake-utils, poetry2nix }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};
        inherit (poetry2nix.lib.mkPoetry2Nix { inherit pkgs; }) mkPoetryApplication;
      in
      {
        packages = {
          bear = mkPoetryApplication {
            packageName = "bearctl";
            projectDir = ./.;

            overrides = poetry2nix.overrides.withDefaults (self: super: {

              pycairo = super.pycairo.overridePythonAttrs (old: {
                nativeBuildInputs =
                  [ self.meson pkgs.buildPackages.pkg-config ];
              });
              pygobject = super.pygobject.overridePythonAttrs (old: {
                buildInputs = (old.buildInputs or [ ]) ++ [ super.setuptools ];
              });

              urllib3 = super.urllib3.overridePythonAttrs (old: {
                buildInputs = (old.buildInputs or [ ]) ++ [ self.hatch-vcs ];
              });

              pipewire-python = super.pipewire-python.overridePythonAttrs
                (old: {
                  buildInputs = (old.buildInputs or [ ]) ++ [ self.flit-core ];
                });

            });
            buildInputs =
              (with pkgs; [ pkgs.pipewire pkgs.lorri pkgs.xorg.xset pkgs.i3 ]);
          };
          default = self.packages.${system}.bear;
        };

        devShells.default = pkgs.mkShell {
          inputsFrom = [ self.packages.${system}.myapp ];
          packages = [ pkgs.poetry ];
        };
      });
}

报错信息 #

✦ ❯ nix build .    
warning: Git tree '/home/robin/devel/bearctl' is dirty
error:
       … while evaluating the attribute 'packages.x86_64-linux.bear'

         at /nix/store/2xz05z3ar2i1fr06mzr434f6n59513g6-source/flake.nix:88:11:

           87|         packages = {
           88|           bear = mkPoetryApplication {
             |           ^
           89|             packageName = "bearctl";

       … while evaluating the attribute 'pkgs.buildPythonPackage'

         at /nix/store/yy19v2dwb8ldphvia9smajvwv3ycx2c1-source/pkgs/development/interpreters/python/passthrufun.nix:87:5:

           86|     withPackages = import ./with-packages.nix { inherit buildEnv pythonPackages;};
           87|     pkgs = pythonPackages;
             |     ^
           88|     interpreter = "${self}/bin/${executable}";

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: attribute 'overrides' missing

       at /nix/store/2xz05z3ar2i1fr06mzr434f6n59513g6-source/flake.nix:92:25:

           91|
           92|             overrides = poetry2nix.overrides.withDefaults (self: super: {
             |                         ^
           93|

核心问题 #

poetry2nix.overrides并非直接存在于flake输入的poetry2nix对象中，你错误地直接调用了这个不存在的属性。正确的overrides需要从poetry2nix.lib.mkPoetry2Nix生成的上下文获取，或者通过poetry2nix.lib调用。

修正步骤 #

1. 调整overrides的获取方式 #

在let块中，从mkPoetry2Nix的返回值里同时继承overrides：

inherit (poetry2nix.lib.mkPoetry2Nix { inherit pkgs; }) mkPoetryApplication overrides;

然后在mkPoetryApplication中使用这个本地的overrides变量：

overrides = overrides.withDefaults (self: super: {
  # 你的override代码保持不变
});

2. 修正devShell中的包名错误 #

devShell里引用的myapp是不存在的，需要改成实际的包名bear：

inputsFrom = [ self.packages.${system}.bear ];

修正后的完整flake代码 #

{
  description =  "bear";

  inputs = {
    flake-utils.url = "github:numtide/flake-utils";
    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
    poetry2nix = {
      url = "github:nix-community/poetry2nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, flake-utils, poetry2nix }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};
        inherit (poetry2nix.lib.mkPoetry2Nix { inherit pkgs; }) mkPoetryApplication overrides;
      in
      {
        packages = {
          bear = mkPoetryApplication {
            packageName = "bearctl";
            projectDir = ./.;

            overrides = overrides.withDefaults (self: super: {

              pycairo = super.pycairo.overridePythonAttrs (old: {
                nativeBuildInputs =
                  [ self.meson pkgs.buildPackages.pkg-config ];
              });
              pygobject = super.pygobject.overridePythonAttrs (old: {
                buildInputs = (old.buildInputs or [ ]) ++ [ super.setuptools ];
              });

              urllib3 = super.urllib3.overridePythonAttrs (old: {
                buildInputs = (old.buildInputs or [ ]) ++ [ self.hatch-vcs ];
              });

              pipewire-python = super.pipewire-python.overridePythonAttrs
                (old: {
                  buildInputs = (old.buildInputs or [ ]) ++ [ self.flit-core ];
                });

            });
            buildInputs =
              (with pkgs; [ pkgs.pipewire pkgs.lorri pkgs.xorg.xset pkgs.i3 ]);
          };
          default = self.packages.${system}.bear;
        };

        devShells.default = pkgs.mkShell {
          inputsFrom = [ self.packages.${system}.bear ];
          packages = [ pkgs.poetry ];
        };
      });
}

内容的提问来源于stack exchange，提问作者thepandaatemyface