anchor.diff:      owner = "envoyproxy";
       repo = "envoy";
       inherit (srcVer) rev;
  -    hash = "sha256-SthKDMQs5yNU0iouAPVsDeCPKcsBXmO9ebDwu58UQRs=";
  +    sha256 = "sha256-VWcfdoZ1wGkxaf0PZwfiSFg8D/QDIZs4u/iLUnsbjMo=";
   
       postFetch = ''
         chmod -R +w $out
  
positive.code:     # However, the version string is more useful for end-users.
      # These are contained in a attrset of their own to make it obvious that
      # people should update both.
      version = "1.21.4";
      rev = "782ba5e5ab9476770378ec9f1901803e0d38ac41";
    };
  in
  buildBazelPackage rec {
  
negative.code: 
    fetchAttrs = {
      sha256 = {
        x86_64-linux = "sha256-bE28PBQjsOLkxjIoDk6HcELPP3XzvqKKVa7yUbXB1Qk=";
        aarch64-linux = "sha256-Rf7kEBeH72vsvmzKy/7oKQf8cVNVzIcSuXMhrIhMFKM=";
      }.${stdenv.system} or (throw "unsupported system ${stdenv.system}");
      dontUseCmakeConfigure = true;
      dontUseGnConfigure = true;
  