maintainers/flake.nix

{
  outputs = { self, nixpkgs, ... }: let
    system = "x86_64-linux";
    pkgs = nixpkgs.legacyPackages.${system};
    inherit (builtins) genericClosure hasAttr length map;
    inherit (pkgs) runCommandLocal writeText;
    inherit (pkgs.lib) concatLines concatLists concatMap filter isDerivation isList mapAttrsToList;
  in {
    lib = rec {
      drvOutputs = drv:
        if hasAttr "outputs" drv
        then map (output: drv.${output}) drv.outputs
        else [ drv ];
      drvDeps = attrs:
        mapAttrsToList (k: v:
          if isDerivation v then (drvOutputs v)
          else if isList v then concatMap drvOutputs (filter isDerivation v)
          else []
        ) attrs;
      wrap = drv: { key = drv.outPath; inherit drv; };
      buildtimeDerivations = drv0: map (obj: obj.drv) (genericClosure {
        startSet = map wrap (drvOutputs drv0);
        operator = obj: map wrap (concatLists (drvDeps obj.drv.drvAttrs));
      });
      drvMaintainers = drv:
        if ! hasAttr "meta" drv then []
        else if ! hasAttr "maintainers" drv.meta then []
        else drv.meta.maintainers;
      nobodyMaintains = drv:
        hasAttr "meta" drv &&
        hasAttr "maintainers" drv.meta &&
        (length drv.meta.maintainers) == 0;
      stringJoin = objToString: objs: writeText "txt" (concatLines (map objToString objs));
      maintainerToString = m: "${m.name} (${m.email})";
      drvToString = drv: "${drv.name}";
    };
    bundlers."x86_64-linux" = with self.lib; rec {
      default = adopt;
      maintainers = drv: let
        drvs = buildtimeDerivations drv;
        maintainers = concatMap drvMaintainers drvs;
        maintainerNamesList = stringJoin (m: "${m.name} (${m.email})") maintainers;
        uniqNames = runCommandLocal "uniq-maintainers.txt" {} ''
          <${maintainerNamesList} sort | uniq -c > $out
        '';
      in uniqNames;
      adopt = drv: let
        drvs = buildtimeDerivations drv;
        drvsNoMain = filter nobodyMaintains drvs;
        drvNamesList = stringJoin (drv: "${drv.name} ${drv.meta.position}") drvsNoMain;
        uniqNames = runCommandLocal "no-maintainers.txt" {} ''
          <${drvNamesList} sort -u > $out
        '';
      in uniqNames;
    };
  };
}