Horrible, hacky packaging of orjson with Nix

orjson.nix

{ fetchFromGitHub
, python
, maturin
, arrow
, dataclasses
, numpy
, pendulum
, psutil
, pytest
, pytz
, black
, isort
, mypy
, typing-extensions
}:
let
  src = fetchFromGitHub {
    owner = "ijl";
    repo = "orjson";
    rev = "789e03a31e525424dff6c170370f9e483725d508";
    sha256 = "00vhh2x5mb4dx4xk0gi0h0yw29hwargy51ks39dg4i6hc17f9aqs";
  };
  nixpkgs-mozilla = import (fetchFromGitHub {
    owner = "mozilla";
    repo = "nixpkgs-mozilla";
    rev = "e912ed483e980dfb4666ae0ed17845c4220e5e7c";
    # date = 2020-02-19T12:55:00-05:00;
    sha256 = "08fvzb8w80bkkabc1iyhzd15f4sm7ra10jn32kfch5klgl0gj3j3";
  });
  pkgs = import <nixpkgs> {
    overlays =
      [
        nixpkgs-mozilla
        (self: super:
          {
            rustc = self.latest.rustChannels.nightly.rust;
            cargo = self.latest.rustChannels.nightly.rust;
          }
        )
      ];
  };
  naersk = pkgs.callPackage (pkgs.fetchFromGitHub {
    owner = "nmattia";
    repo = "naersk";
    rev = "7d23ad7e33a92434b52129b16f1e2df2a9b8515e";
    sha256 = "11xgjjlp05ymiylb7i18aqrsa7acsifdk7w37jfd4dxmnzm69z1q";
  }) {};
  rustPkg = naersk.buildPackage {
    root = src;
    buildInputs = [ python maturin ];
  };
in buildPythonPackage rec {
  name = "${pname}-${version}";
  pname = "orjson";
  version = "2.6.0";
  inherit src;
  inherit (rustPkg) crate_sources cargoconfig configurePhase RUSTC
    cargo_release cargo_options cargo_build_options cargo_test_options
    cargo_bins_jq_filter;

  nativeBuildInputs = rustPkg.nativeBuildInputs ++ [ pkgs.maturin ];

  buildPhase = ''
    export RUSTFLAGS="-Zmutable-noalias -C target-feature=+sse2 $RUSTFLAGS"
    maturin build --manylinux off --no-sdist --release -i python3.6 -o dist
  '';

  installCheckPhase = ''
    pytest test
  '';

  propagatedBuildInputs = [
    black
    isort
    mypy
    typing-extensions
  ];

  checkInputs = [
    arrow
    dataclasses
    numpy
    pendulum
    psutil
    pytest
    pytz
    typing-extensions
  ];
}