bridle

{
  python3,
  zephyr,
  bridle,
  python-deps,
  pyproject-nix,
  clang-tools,
  gitlint,
  lib,
}:

let

  # Create a python whose `withPackages` knows about some extra stuff we need
  python = python3.override {
    self = python;
    packageOverrides = final: prev: {
      # HACK: Zephyr uses pypi to install non-Python deps
      clang-format = clang-tools;
      inherit gitlint;

      # Extra python packages that aren't in nixpkgs
      inherit (python-deps)
        bz
        doxmlparser
        pydebuggerconfig
        pyedbglib
        pykitinfo
        pymcuprog
        python-can
        sphinx-tsn-theme
        sphinxcontrib-svg2pdfconverter
        sphinx-csv-filter
        ;

      # WORKAROUND for missing defusedxml in nativeCheckInputs of sphinx-sitemap derivation.
      sphinx-sitemap = prev.sphinx-sitemap.overrideAttrs (old: {
        pytestCheckPhase = ''true'';
      });
    };
  };

  # Parse requirements.txt files into pyproject-nix projects
  zephyr-project = pyproject-nix.lib.project.loadRequirementsTxt {
    requirements = zephyr + "/scripts/requirements.txt";
  };

  bridle-project = pyproject-nix.lib.project.loadRequirementsTxt {
    requirements = bridle + "/scripts/requirements.txt";
  };

  # Can't validate the combined packages sets, but we can at least check for
  # conflicts within each subset
  invalidConstraints =
    zephyr-project.validators.validateVersionConstraints { inherit python; }
    // bridle-project.validators.validateVersionConstraints { inherit python; };

in
lib.warnIf (invalidConstraints != { })
  "pythonEnv: Found invalid Python constraints for: ${builtins.toJSON (lib.attrNames invalidConstraints)}"
  (
    python.buildEnv.override {
      extraLibs =
        (bridle-project.renderers.withPackages {
          inherit python;
          # Nest one project's withPackages within the other to get a combined package
          # set. If we want more than two, we should name these lambdas to reduce
          # indentation.
          extraPackages = (
            zephyr-project.renderers.withPackages {
              inherit python;
              extraPackages = ps: [ ps.west ];
            }
          );
        })
          python.pkgs;
      ignoreCollisions = true;
    }
  )