anchor.diff:  
     src = fetchurl {
       url = "https://artifacts.elastic.co/downloads/elasticsearch/${name}.tar.gz";
  -    inherit (source) sha1Confirm sha256;
  +    hashOutput = false;
  +    inherit (source) sha256;
     };
   
     nativeBuildInputs = [
  
positive.code:       --set JAVA_HOME "${openjdk}"
    '';
  
    meta = with lib; {
      description = "Distributed RESTful search engine built on top of Lucene";
      homepage = https://www.elastic.co/products/elasticsearch;
  
negative.code: 
    sources = {
      "5.5" = {
        version = "5.6.1";
        sha256 = "006f9cb3886877df845e3c3dea8a688777fb739a862d3afe1a113c16a732715f";
      };
      "6.0" = {
        version = "6.0.0-beta2";
        sha256 = "0c200154c4980ad6e278d9c9ee9e2ca22d2c501c4c67e6fe748adde31aa36b0e";
      };
    };
  