build-support/docker: use runCommand in make-layers.nix

  flattenReferencesGraph,

  lib,

  jq,

  stdenvNoCC,

  runCommand,

}:

{

  closureRoots,

if closureRoots == [ ] then

  builtins.toFile "docker-layers-empty" "[]"

else

  stdenvNoCC.mkDerivation {

    name = "docker-layers";

  runCommand "docker-layers"

    {

      __structuredAttrs = true;

      # graph, exclude_paths and pipeline are expected by the

      # flatten_references_graph executable.

      exportReferencesGraph.graph = closureRoots;

      exclude_paths = excludePaths;

      inherit pipeline;

    # builder cannot refer to derivation outputs

    PATH = "${coreutils}/bin:${flattenReferencesGraph}/bin:${jq}/bin";

    builder = builtins.toFile "docker-make-layers-builder" ''

      nativeBuildInputs = [

        coreutils

        flattenReferencesGraph

        jq

      ];

    }

    ''

      . .attrs.sh

      flatten_references_graph_arg=.attrs.json

      ${lib.optionalString debug "export DEBUG=True"}

      flatten_references_graph "$flatten_references_graph_arg" > ''${outputs[out]}

    '';

  }

    ''