uhd: fix python api feature by not using a pythonEnv

, boost

, ncurses

, enableCApi ? true

# Although we handle the Python API's dependencies in pythonEnvArg, this

# feature is currently disabled as upstream attempts to run `python setup.py

# install` by itself, and it fails because the Python's environment's prefix is

# not a writable directly. Adding support for this feature would require using

# python's pypa/build nad pypa/install hooks directly, and currently it is hard

# to do that because it all happens after a long buildPhase of the C API.

, enablePythonApi ? false

, enablePythonApi ? true

, python3

, buildPackages

, enableExamples ? false

, enableUtils ? true

, libusb1

let

  inherit (lib) optionals cmakeBool;

  # Later used in pythonEnv generation. Python + mako are always required for the build itself but not necessary for runtime.

  pythonEnvArg = (ps: with ps; [ mako ]

    ++ optionals (enablePythonApi) [ numpy setuptools ]

    ++ optionals (enableUtils) [ requests six ]

  );

in

stdenv.mkDerivation (finalAttrs: {

    # hash.

    sha256 = "17g503mhndaabrdl7qai3rdbafr8xx8awsyr7h2bdzwzprzmh4m3";

  };

  # This are the minimum required Python dependencies, this attribute might

  # be useful if you want to build a development environment with a python

  # interpreter able to import the uhd module.

  pythonPath = optionals (enablePythonApi || enableUtils) [

    python3.pkgs.numpy

    python3.pkgs.setuptools

  ] ++ optionals (enableUtils) [

    python3.pkgs.requests

    python3.pkgs.six

  ];

  passthru = {

    runtimePython = python3.withPackages (ps: finalAttrs.pythonPath);

    updateScript = [

      ./update.sh

      # Pass it this file name as argument

    (cmakeBool "ENABLE_UTILS" enableUtils)

    (cmakeBool "ENABLE_C_API" enableCApi)

    (cmakeBool "ENABLE_PYTHON_API" enablePythonApi)

    /*

    Otherwise python tests fail. Using a dedicated pythonEnv for either or both

    nativeBuildInputs and buildInputs makes upstream's cmake scripts fail to

    install the Python API as reported on our end at [1] (we don't want

    upstream to think we are in a virtual environment because we use

    python3.withPackages...).

    Putting simply the python dependencies in the nativeBuildInputs and

    buildInputs as they are now from some reason makes the `python` in the

    checkPhase fail to find the python dependencies, as reported at [2]. Even

    using nativeCheckInputs with the python dependencies, or using a

    `python3.withPackages` wrapper in nativeCheckInputs, doesn't help, as the

    `python` found in $PATH first is the one from nativeBuildInputs.

    [1]: https://github.com/NixOS/nixpkgs/pull/307435

    [2]: https://discourse.nixos.org/t/missing-python-package-in-checkphase/9168/

    Hence we use upstream's provided cmake flag to control which python

    interpreter they will use to run the the python tests.

    */

    "-DRUNTIME_PYTHON_EXECUTABLE=${lib.getExe finalAttrs.passthru.runtimePython}"

    (cmakeBool "ENABLE_DPDK" enableDpdk)

    # Devices

    (cmakeBool "ENABLE_OCTOCLOCK" enableOctoClock)

    "-DCMAKE_CXX_FLAGS=-Wno-psabi"

  ];

  pythonEnv = python3.withPackages pythonEnvArg;

  nativeBuildInputs = [

    cmake

    pkg-config

    # Present both here and in buildInputs for cross compilation.

    (buildPackages.python3.withPackages pythonEnvArg)

    python3

    python3.pkgs.mako

    # We add this unconditionally, but actually run wrapPythonPrograms only if

    # python utilities are enabled

    python3.pkgs.wrapPython

  ];

  buildInputs = [

  buildInputs = finalAttrs.pythonPath ++ [

    boost

    libusb1

    # However, if enableLibuhd_Python_api *or* enableUtils is on, we need

    # pythonEnv for runtime as well. The utilities' runtime dependencies are

    # handled at the environment

  ] ++ optionals (enableExamples) [

    ncurses ncurses.dev

  ] ++ optionals (enablePythonApi || enableUtils) [

    finalAttrs.pythonEnv

  ] ++ optionals (enableDpdk) [

    dpdk

  ];

    mv $out/lib/uhd/utils/uhd-usrp.rules $out/lib/udev/rules.d/

  '';

  # Wrap the python utilities with our pythonPath definition

  postFixup = lib.optionalString (enablePythonApi && enableUtils) ''

    wrapPythonPrograms

  '';

  disallowedReferences = optionals (!enablePythonApi && !enableUtils) [

    python3

  ];