anchor.diff:    meta = {
       description = "Version Control for your database";
       homepage = http://www.liquibase.org/;
  +    changelog = "https://raw.githubusercontent.com/liquibase/liquibase/v${version}/changelog.txt";
       license = licenses.asl20;
       maintainers = with maintainers; [ nequissimus ];
       platforms = with platforms; unix;
  
positive.code: with stdenv.lib;
  let
    extraJars = optional mysqlSupport mysql_jdbc;
    logback-core = fetchurl {
      url = "http://central.maven.org/maven2/ch/qos/logback/logback-core/1.2.3/logback-core-1.2.3.jar";
      sha256 = "5946d837fe6f960c02a53eda7a6926ecc3c758bbdd69aa453ee429f858217f22";
    };
    logback-classic = fetchurl {
      url = "http://central.maven.org/maven2/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar";
      sha256 = "fb53f8539e7fcb8f093a56e138112056ec1dc809ebb020b59d8a36a5ebac37e0";
    };
    slf4j = fetchurl {
      url = "http://central.maven.org/maven2/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar";
      sha256 = "18c4a0095d5c1da6b817592e767bb23d29dd2f560ad74df75ff3961dbde25b79";
    };
  in
  
  stdenv.mkDerivation rec {
    pname = "liquibase";
    version = "3.6.2";
  
    src = fetchurl {
      url = "https://github.com/liquibase/liquibase/releases/download/${pname}-parent-${version}/${pname}-${version}-bin.tar.gz";
      sha256 = "199ybjk0xxsg04v5x5l4arljmzj96hxva6ym6bp7av7dny0nqvfx";
    };
  
    buildInputs = [ jre makeWrapper ];
  
negative.code:       done
      '';
      in ''
        mkdir -p $out
        mv ./{lib,licenses,liquibase.jar} $out/
  
        mkdir -p $out/share/doc/${pname}-${version}
        mv LICENSE.txt \
           README.txt \
           ABOUT.txt \
           changelog.txt \
           $out/share/doc/${pname}-${version}
  
        mkdir -p $out/bin
        # there’s a lot of escaping, but I’m not sure how to improve that
        cat > $out/bin/liquibase <<EOF
        #!/usr/bin/env bash
  