Find python packages that are likely to fail when used through "nix-shell -p"

default.nix

# Produce a list of derivations that should likely have pythonPath set

with import <nixpkgs> {};

with builtins;
let
  # Package set to check
  pythonPackages = pkgs.python2Packages;

  # evaluate expr, returning default on error
  tryDefault = expr: default:
    let
      res = (tryEval expr);
    in if res.success then res.value else default;

  
  isPython = pkg: pkg?name && (parseDrvName pkg.name).name == "python";
  hasPropagatedPython = pkg: (pkg?propagatedNativeBuildInputs && (length (filter isPython pkg.propagatedNativeBuildInputs)) > 0);

  # Skip broken packages and packages that don't support the given python version
  validPythonPackage = pkg: tryDefault (pkg?disabled -> !pkg.disabled) false;

  validPythonPackages = pkgs: (filter validPythonPackage (attrValues pkgs));
  withoutPropagatedPython = pkgs: filter (pkg: tryDefault (pkg?name && !(hasPropagatedPython pkg)) false) (validPythonPackages pkgs);

  pkgsWithoutPropagatedPython = builtins.map (pkg: pkg.name) (withoutPropagatedPython pythonPackages);

in pkgs.writeTextFile {
  name = "python-packages-without-pythonpath.json";
  text = toJSON pkgsWithoutPropagatedPython;
}