depot/packages/build-support/drv-parts/backends/buildPythonPackage/implementation.nix

{ config, packageSets, drv-parts, lib, ... }:

let
  inherit (config) deps;

  withDistOutput = lib.elem config.format [
    "pyproject"
    "setuptools"
    "flit"
    "wheel"
  ];

  hasPyproject = config.format == "pyproject" && config.pyprojectToml != null;

  pyproject = if hasPyproject then
    lib.importTOML config.pyprojectToml
  else
    null;
in

{
  imports = [
    drv-parts.modules.drv-parts.mkDerivation
  ];

  name = lib.mkIf hasPyproject (lib.mkDefault pyproject.tool.poetry.name);
  version = lib.mkIf hasPyproject (lib.mkDefault pyproject.tool.poetry.version);

  deps = { pkgs, python3Packages, ... }: {
    inherit (python3Packages)
      python
      wrapPython
      pythonRemoveTestsDirHook
      pythonCatchConflictsHook
      pythonRemoveBinBytecodeHook
      unzip
      setuptoolsBuildHook
      flitBuildHook
      pipBuildHook
      wheelUnpackHook
      eggUnpackHook eggBuildHook eggInstallHook
      pipInstallHook
      pythonImportsCheckHook
      pythonNamespacesHook
      pythonOutputDistHook
    ;
    inherit (pkgs)
      ensureNewerSourcesForZipFilesHook
      stdenv
    ;
  };

  env = {
    LANG = "${if deps.python.stdenv.isDarwin then "en_US" else "C"}.UTF-8";
  };

  mkDerivation = {

    nativeBuildInputs = with deps; [
      python
      wrapPython
      ensureNewerSourcesForZipFilesHook
      pythonRemoveTestsDirHook
    ] ++ lib.optionals config.catchConflicts [
      pythonCatchConflictsHook
    ] ++ lib.optionals config.removeBinByteCode [
      pythonRemoveBinBytecodeHook
    ] ++ lib.optionals (lib.hasSuffix "zip" (config.src.name or "")) [
      unzip
    ] ++ lib.optionals (config.format == "setuptools") [
      setuptoolsBuildHook
    ] ++ lib.optionals (config.format == "flit") [
      flitBuildHook
    ] ++ lib.optionals (config.format == "pyproject") [
      pipBuildHook
    ] ++ lib.optionals (config.format == "wheel") [
      wheelUnpackHook
    ] ++ lib.optionals (config.format == "egg") [
      eggUnpackHook eggBuildHook eggInstallHook
    ] ++ lib.optionals (!(config.format == "other") || config.dontUsePipInstall) [
      pipInstallHook
    ] ++ lib.optionals (python.stdenv.buildPlatform == python.stdenv.hostPlatform) [
      # This is a test, however, it should be ran independent of the checkPhase and checkInputs
      pythonImportsCheckHook
    ] ++ lib.optionals (python.pythonAtLeast "3.3") [
      # Optionally enforce PEP420 for python3
      pythonNamespacesHook
    ] ++ lib.optionals withDistOutput [
      pythonOutputDistHook
    ];

    propagatedBuildInputs = with deps; [
      python
    ];

    doCheck = false;
    doInstallCheck = lib.mkDefault true;
    installCheckInputs = lib.optionals (config.format == "setuptools") [
      deps.setuptoolsCheckHook
    ];

    postFixup = lib.mkBefore (lib.optionalString (!config.dontWrapPythonPrograms) ''
      wrapPythonPrograms
    '');

    outputs = [ "out" ] ++ lib.optional withDistOutput "dist";
  };
}