Merge branch 'staging-next' into staging

* `disabled` ? false: If `true`, package is not build for the particular Python interpreter version.

* `dontWrapPythonPrograms ? false`: Skip wrapping of python programs.

* `installFlags ? []`: A list of strings. Arguments to be passed to `pip install`. To pass options to `python setup.py install`, use `--install-option`. E.g., `installFlags=["--install-option='--cpp_implementation'"]`.

* `format ? "setuptools"`: Format of the source. Valid options are `"setuptools"`, `"flit"`, `"wheel"`, and `"other"`. `"setuptools"` is for when the source has a `setup.py` and `setuptools` is used to build a wheel, `flit`, in case `flit` should be used to build a wheel, and `wheel` in case a wheel is provided. Use `other` when a custom `buildPhase` and/or `installPhase` is needed.

* `format ? "setuptools"`: Format of the source. Valid options are `"setuptools"`, `"pyproject"`, `"flit"`, `"wheel"`, and `"other"`. `"setuptools"` is for when the source has a `setup.py` and `setuptools` is used to build a wheel, `flit`, in case `flit` should be used to build a wheel, and `wheel` in case a wheel is provided. Use `other` when a custom `buildPhase` and/or `installPhase` is needed.

* `makeWrapperArgs ? []`: A list of strings. Arguments to be passed to `makeWrapper`, which wraps generated binaries. By default, the arguments to `makeWrapper` set `PATH` and `PYTHONPATH` environment variables before calling the binary. Additional arguments here can allow a developer to set environment variables which will be available when the binary is run. For example, `makeWrapperArgs = ["--set FOO BAR" "--set BAZ QUX"]`.

* `namePrefix`: Prepends text to `${name}` parameter. In case of libraries, this defaults to `"python3.5-"` for Python 3.5, etc., and in case of applications to `""`.

* `pythonPath ? []`: List of packages to be added into `$PYTHONPATH`. Packages in `pythonPath` are not propagated (contrary to `propagatedBuildInputs`).

    '';

  }

  ```

- Unicode issues can typically be fixed by including `glibcLocales` in `buildInputs` and exporting `LC_ALL=en_US.utf-8`.

- Tests that attempt to access `$HOME` can be fixed by using the following work-around before running tests (e.g. `preCheck`): `export HOME=$(mktemp -d)`

## FAQ

   </listitem>

   <listitem>

    <para>

      The <varname>buildPythonPackage</varname> now sets <varname>strictDeps = true</varname>

      The <varname>buildPythonPackage</varname> function now sets <varname>strictDeps = true</varname>

      to help distinguish between native and non-native dependencies in order to

      improve cross-compilation compatibility. Note however that this may break

      user expressions.

    </para>

   </listitem>

   <listitem>

    <para>

      The <varname>buildPythonPackage</varname> function now sets <varname>LANG = C.UTF-8</varname>

      to enable Unicode support. The <varname>glibcLocales</varname> package is no longer needed as a build input.

    </para>

   </listitem>

   <listitem>

    <para>

      The Syncthing state and configuration data has been moved from

# This function provides specific bits for building a setuptools-based Python package.

{ lib

, python

}:

{

# passed to "python setup.py build_ext"

# https://github.com/pypa/pip/issues/881

# Rename to `buildOptions` because it is not setuptools specific?

  setupPyBuildFlags ? []

# Execute before shell hook

, preShellHook ? ""

# Execute after shell hook

, postShellHook ? ""

, ... } @ attrs:

let

  options = lib.concatMapStringsSep " " (option: "--global-option ${option}") setupPyBuildFlags;

in attrs // {

  buildPhase = attrs.buildPhase or ''

    runHook preBuild

    mkdir -p dist

    echo "Creating a wheel..."

    ${python.pythonForBuild.interpreter} -m pip wheel --no-index --no-deps --no-clean --no-build-isolation --wheel-dir dist ${options} .

    echo "Finished creating a wheel..."

    runHook postBuild

  '';

  installCheckPhase = ''

    runHook preCheck

    echo "No checkPhase defined. Either provide a checkPhase or disable tests in case tests are not available."; exit 1

    runHook postCheck

  '';

  # With Python it's a common idiom to run the tests

  # after the software has been installed.

  doCheck = attrs.doCheck or true;

  shellHook = attrs.shellHook or ''

    ${preShellHook}

    # Long-term setup.py should be dropped.

    if [ -e pyproject.toml ]; then

      tmp_path=$(mktemp -d)

      export PATH="$tmp_path/bin:$PATH"

      export PYTHONPATH="$tmp_path/${python.pythonForBuild.sitePackages}:$PYTHONPATH"

      mkdir -p $tmp_path/${python.pythonForBuild.sitePackages}

      ${python.pythonForBuild.pkgs.bootstrapped-pip}/bin/pip install -e . --prefix $tmp_path >&2

    fi

    ${postShellHook}

  '';

}

 No newline at end of file

let

  setuptools-specific = import ./build-python-package-setuptools.nix { inherit lib python; };

  pyproject-specific = import ./build-python-package-pyproject.nix { inherit lib python; };

  flit-specific = import ./build-python-package-flit.nix { inherit python flit; };

  wheel-specific = import ./build-python-package-wheel.nix { };

  common = import ./build-python-package-common.nix { inherit python; };

let

  formatspecific =

    if format == "setuptools" then common (setuptools-specific attrs)

    if format == "pyproject" then common (pyproject-specific attrs)

    else if format == "setuptools" then common (setuptools-specific attrs)

    else if format == "flit" then common (flit-specific attrs)

    else if format == "wheel" then common (wheel-specific attrs)

    else if format == "other" then {}

  # Enabled to detect some (native)BuildInputs mistakes

  strictDeps = true;

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

  # Python packages don't have a checkPhase, only an installCheckPhase

  doCheck = false;

  doInstallCheck = doCheck;