anchor.diff:  assert elem stdenv.system [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
   
   let
  -  common = { pname, version, untarDir ? "${pname}-${version}", sha256, jdk, openssl ? null, nativeLibs ? [ ], libPatches ? "", tests }:
  +  common = { pname, versions, untarDir ? "${pname}-${version}", hash, jdk, openssl ? null, nativeLibs ? [ ], libPatches ? "", tests }:
       stdenv.mkDerivation rec {
  -      inherit pname version jdk libPatches untarDir openssl;
  +      inherit pname jdk libPatches untarDir openssl;
  +      version = versions.${stdenv.system};
         src = fetchurl {
           url = "mirror://apache/hadoop/common/hadoop-${version}/hadoop-${version}" + optionalString stdenv.isAarch64 "-aarch64" + ".tar.gz";
  -        sha256 = sha256.${stdenv.system};
  +        hash = hash.${stdenv.system};
         };
         doCheck = true;
   
  
positive.code:           computers, each of which may be prone to failures.
          '';
          maintainers = with maintainers; [ illustris ];
          platforms = attrNames sha256;
        };
      };
  in
  
negative.code:   };
    hadoop_3_2 = common rec {
      pname = "hadoop";
      versions.x86_64-linux = "3.2.3";
      hash.x86_64-linux = "sha256-Q2/a1LcKutpJoGySB0qlCcYE2bvC/HoG/dp9nBikuNU=";
      jdk = jdk8_headless;
      # not using native libs because of broken openssl_1_0_2 dependency
      # can be manually overriden
  