anchor.diff:        inherit name sha256 version;
         url = "https://gitlab.com/${owner}/${repo}/repository/"
           + "archive.tar.gz?ref=${rev}";
  -      meta.homepage = "https://gitlab.com/${owner}/${repo}/";
       };
   
     fetchFromRepoOrCz =
  
positive.code:       # cgit, snapshot support is optional in cgit
        url = "http://git.savannah.gnu.org/cgit/${repo}.git/snapshot/"
          + "${repo}-${rev}.tar.gz";
        meta.homepage = "http://git.savannah.gnu.org/cgit/${repo}.git/";
      };
  
    fetchFromGitLab =
  
negative.code:         sha256
          version;
        url = "https://bitbucket.org/${owner}/${repo}/get/${rev}.tar.gz";
        extraPostFetch = ''
          # impure file, see https://github.com/NixOS/nixpkgs/pull/12002
          find . -name .hg_archival.txt -delete
  