anchor.diff:      attrPath = package.updateScript.attrPath or attrPath;
     };
   
  +  /* JSON file with data for update.py.
  +   */
     packagesJson = pkgs.writeText "packages.json" (builtins.toJSON (map packageData packages));
   
     optionalArgs =
  
positive.code:         --argstr commit true
    '';
  
    packageData = { package, attrPath }: {
      name = package.name;
      pname = lib.getName package;
  
negative.code:         else
            builtins.getAttr maintainer' lib.maintainers;
      in
        packagesWith (path: pkg: builtins.hasAttr "updateScript" pkg &&
                           (if builtins.hasAttr "maintainers" pkg.meta
                             then (if builtins.isList pkg.meta.maintainers
                                     then builtins.elem maintainer pkg.meta.maintainers
                                     else maintainer == pkg.meta.maintainers
                                  )
                             else false
                           )
                     );
  
    /* Recursively find all packages under `path` in `pkgs` with updateScript.
     */
    packagesWithUpdateScript = path: pkgs:
      let
        prefix = lib.splitString "." path;
        pathContent = lib.attrByPath prefix null pkgs;
  