anchor.diff:  
     image-spec = buildFromGitHub {
       version = 3;
  -    rev = "af173bcb2fb0e0b95f240b914c4791f69738b765";
  +    rev = "d9ffa2f05d4dbe917edfdffcafaf427287a26d1c";
       owner  = "opencontainers";
       repo   = "image-spec";
  -    sha256 = "0rpvjrg8b6amjnnr81nzvy4dqzd4szk83r9ssjw7vw80v7idv9py";
  -    date = "2017-06-23";
  +    sha256 = "0i101m71vcm5sx91q9hrh5xs79ziyjx3qqz9a328j8h9ghg1mwan";
  +    date = "2017-06-26";
       propagatedBuildInputs = [
         errors
         go4
  
positive.code: 
    docker_cli = buildFromGitHub {
      version = 3;
      date = "2017-06-23";
      rev = "8b6196ded7d610bfec0c2fea0cb1ff6df5f6cbf8";
      owner = "docker";
      repo = "cli";
      sha256 = "1c40hw46knqkkqbilg2a874pbcnb6y62jr5vqm36nakj99cbyidf";
      subPackages = [
        "cli/config/configfile"
        "opts"
  
negative.code: 
    sys = buildFromGitHub {
      version = 3;
      rev = "f7928cfef4d09d1b080aa2b6fd3ca9ba1567c733";
      date = "2017-06-27";
      owner  = "golang";
      repo   = "sys";
      sha256 = "0rca37y5dklljmvjpa7fjh5np8c1x58m5w9snxf74d7nzk0g1x06";
      goPackagePath = "golang.org/x/sys";
    };
  
  