anchor.diff:    name = attrs.name or "${namePrefix}${gemName}-${version}";
   
     inherit src;
  +
   
     unpackPhase = attrs.unpackPhase or ''
       runHook preUnpack
  
positive.code:     else if type == "git" then
        fetchgit {
          inherit (attrs.source) url rev sha256 fetchSubmodules;
          leaveDotGit = true;
        }
      else if type == "url" then
        fetchurl attrs.source
  
negative.code:       gempkg=$(echo "$output" | grep -oP 'File: \K(.*)')
  
        echo "gem package built: $gempkg"
      elif [[ "$type" == "git" ]]; then
        git init
        # remove variations to improve the likelihood of a bit-reproducible output
        rm -rf .git/logs/ .git/hooks/ .git/index .git/FETCH_HEAD .git/ORIG_HEAD .git/refs/remotes/origin/HEAD .git/config
        # support `git ls-files`
        git add .
      fi
  
      runHook postBuild
  