core/pkgs/by-name/py/python/python2/mk-python-derivation.nix

# Generic builder only used for EOL and deprecated Python 2.

{ lib, config, python, wrapPython, unzip, ensureNewerSourcesForZipFilesHook
# Whether the derivation provides a Python module or not.
, toPythonModule, namePrefix, update-python-libraries, setuptools, pipBuildHook
, pipInstallHook, pythonCatchConflictsHook, pythonImportsCheckHook
, pythonOutputDistHook, pythonRemoveBinBytecodeHook, pythonRemoveTestsDirHook
, setuptoolsBuildHook, setuptoolsCheckHook, wheelUnpackHook, eggUnpackHook
, eggBuildHook, eggInstallHook }:

{ name ? "${attrs.pname}-${attrs.version}"

  # Build-time dependencies for the package
, nativeBuildInputs ? [ ]

  # Run-time dependencies for the package
, buildInputs ? [ ]

  # Dependencies needed for running the checkPhase.
  # These are added to buildInputs when doCheck = true.
, checkInputs ? [ ], nativeCheckInputs ? [ ]

  # propagate build dependencies so in case we have A -> B -> C,
  # C can import package A propagated by B
, propagatedBuildInputs ? [ ]

  # DEPRECATED: use propagatedBuildInputs
, pythonPath ? [ ]

  # Enabled to detect some (native)BuildInputs mistakes
, strictDeps ? true

, outputs ? [
  "out"
]

# used to disable derivation, useful for specific python versions
, disabled ? false

  # Raise an error if two packages are installed with the same name
  # TODO: For cross we probably need a different PYTHONPATH, or not
  # add the runtime deps until after buildPhase.
, catchConflicts ? (python.stdenv.hostPlatform == python.stdenv.buildPlatform)

# Additional arguments to pass to the makeWrapper function, which wraps
# generated binaries.
, makeWrapperArgs ? [ ]

  # Skip wrapping of python programs altogether
, dontWrapPythonPrograms ? false

  # Don't use Pip to install a wheel
  # Note this is actually a variable for the pipInstallPhase in pip's setupHook.
  # It's included here to prevent an infinite recursion.
, dontUsePipInstall ? false

  # Skip setting the PYTHONNOUSERSITE environment variable in wrapped programs
, permitUserSite ? false

  # Remove bytecode from bin folder.
  # When a Python script has the extension `.py`, bytecode is generated
  # Typically, executables in bin have no extension, so no bytecode is generated.
  # However, some packages do provide executables with extensions, and thus bytecode is generated.
, removeBinBytecode ? true

  # Several package formats are supported.
  # "setuptools" : Install a common setuptools/distutils based package. This builds a wheel.
  # "wheel" : Install from a pre-compiled wheel.
  # "pyproject": Install a package using a ``pyproject.toml`` file (PEP517). This builds a wheel.
  # "egg": Install a package from an egg.
  # "other" : Provide your own buildPhase and installPhase.
, format ? "setuptools"

, meta ? { }

, passthru ? { }

, doCheck ? config.doCheckByDefault or false

, disabledTestPaths ? [ ]

, ... }@attrs:

let
  inherit (python) stdenv;

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

  name_ = name;

  validatePythonMatches = attrName:
    let
      isPythonModule = drv:
        # all pythonModules have the pythonModule attribute
        (drv ? "pythonModule")
        # Some pythonModules are turned in to a pythonApplication by setting the field to false
        && (!builtins.isBool drv.pythonModule);
      isMismatchedPython = drv: drv.pythonModule != python;

      optionalLocation = let
        pos = builtins.unsafeGetAttrPos
          (if attrs ? "pname" then "pname" else "name") attrs;
      in lib.optionalString (pos != null)
      " at ${pos.file}:${toString pos.line}:${toString pos.column}";

      leftPadName = name: against:
        let len = lib.max (lib.stringLength name) (lib.stringLength against);
        in lib.strings.fixedWidthString len " " name;

      throwMismatch = drv:
        let
          myName = "'${namePrefix}${name}'";
          theirName = "'${drv.name}'";
        in throw ''
          Python version mismatch in ${myName}:

          The Python derivation ${myName} depends on a Python derivation
          named ${theirName}, but the two derivations use different versions
          of Python:

              ${leftPadName myName theirName} uses ${python}
              ${leftPadName theirName myName} uses ${toString drv.pythonModule}

          Possible solutions:

            * If ${theirName} is a Python library, change the reference to ${theirName}
              in the ${attrName} of ${myName} to use a ${theirName} built from the same
              version of Python

            * If ${theirName} is used as a tool during the build, move the reference to
              ${theirName} in ${myName} from ${attrName} to nativeBuildInputs

            * If ${theirName} provides executables that are called at run time, pass its
              bin path to makeWrapperArgs:

                  makeWrapperArgs = [ "--prefix PATH : ''${lib.makeBinPath [ ${
                    lib.getName drv
                  } ] }" ];

          ${optionalLocation}
        '';

      checkDrv = drv:
        if (isPythonModule drv) && (isMismatchedPython drv) then
          throwMismatch drv
        else
          drv;

    in inputs: builtins.map (checkDrv) inputs;

  # Keep extra attributes from `attrs`, e.g., `patchPhase', etc.
  self = toPythonModule (stdenv.mkDerivation ((builtins.removeAttrs attrs [
    "disabled"
    "checkPhase"
    "checkInputs"
    "nativeCheckInputs"
    "doCheck"
    "doInstallCheck"
    "dontWrapPythonPrograms"
    "catchConflicts"
    "format"
    "disabledTestPaths"
    "outputs"
  ]) // {

    name = namePrefix + name_;

    nativeBuildInputs = [
      python
      wrapPython
      ensureNewerSourcesForZipFilesHook # move to wheel installer (pip) or builder (setuptools, ...)?
      pythonRemoveTestsDirHook
    ] ++ lib.optionals catchConflicts [ pythonCatchConflictsHook ]
      ++ lib.optionals removeBinBytecode [ pythonRemoveBinBytecodeHook ]
      ++ lib.optionals (lib.hasSuffix "zip" (attrs.src.name or "")) [ unzip ]
      ++ lib.optionals (format == "setuptools") [ setuptoolsBuildHook ]
      ++ lib.optionals (format == "pyproject") [ (pipBuildHook) ]
      ++ lib.optionals (format == "wheel") [ wheelUnpackHook ]
      ++ lib.optionals (format == "egg") [
        eggUnpackHook
        eggBuildHook
        eggInstallHook
      ] ++ lib.optionals (format != "other") [ (pipInstallHook) ]
      ++ lib.optionals (stdenv.buildPlatform == stdenv.hostPlatform) [
        # This is a test, however, it should be ran independent of the checkPhase and checkInputs
        pythonImportsCheckHook
      ] ++ lib.optionals withDistOutput [ pythonOutputDistHook ]
      ++ nativeBuildInputs;

    buildInputs =
      validatePythonMatches "buildInputs" (buildInputs ++ pythonPath);

    propagatedBuildInputs = validatePythonMatches "propagatedBuildInputs"
      (propagatedBuildInputs ++ [
        # we propagate python even for packages transformed with 'toPythonApplication'
        # this pollutes the PATH but avoids rebuilds
        # see https://github.com/NixOS/nixpkgs/issues/170887 for more context
        python
      ]);

    inherit strictDeps;

    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 = attrs.doCheck or true;
    nativeInstallCheckInputs = [ ] ++ lib.optionals (format == "setuptools") [
      # Longer-term we should get rid of this and require
      # users of this function to set the `installCheckPhase` or
      # pass in a hook that sets it.
      setuptoolsCheckHook
    ] ++ nativeCheckInputs;
    installCheckInputs = checkInputs;

    postFixup = lib.optionalString (!dontWrapPythonPrograms) ''
      wrapPythonPrograms
    '' + attrs.postFixup or "";

    # Python packages built through cross-compilation are always for the host platform.
    disallowedReferences =
      lib.optionals (python.stdenv.hostPlatform != python.stdenv.buildPlatform)
      [ python.pythonOnBuildForHost ];

    outputs = outputs ++ lib.optional withDistOutput "dist";

    meta = {
      # default to python's platforms
      platforms = python.meta.platforms;
      isBuildPythonPackage = python.meta.platforms;
    } // meta;
  } // lib.optionalAttrs (attrs ? checkPhase) {
    # If given use the specified checkPhase, otherwise use the setup hook.
    # Longer-term we should get rid of `checkPhase` and use `installCheckPhase`.
    installCheckPhase = attrs.checkPhase;
  } // lib.optionalAttrs (disabledTestPaths != [ ]) {
    disabledTestPaths = lib.escapeShellArgs disabledTestPaths;
  }));

  passthru.updateScript =
    let filename = builtins.head (lib.splitString ":" self.meta.position);
    in attrs.passthru.updateScript or [ update-python-libraries filename ];
in lib.extendDerivation
(disabled -> throw "${name} not supported for interpreter ${python.executable}")
passthru self