anchor.diff:  
     src = fetchgit ( removeAttrs (builtins.fromJSON ''{
     "url": "https://github.com/lewis6991/gitsigns.nvim",
  -  "rev": "5eb87a0b05914d3763277ebe257bd5bafcdde8cd",
  -  "date": "2021-12-06T18:02:22+00:00",
  -  "path": "/nix/store/c5l5bz7m5f48l57p4yrpxfhqga0cxsny-gitsigns.nvim",
  -  "sha256": "02cmgc3fgrwx6v6ylzqxdwgk9jsmd8j2q6fdnfbllg3zjwx3agcd",
  +  "rev": "27aeb2e715c32cbb99aa0b326b31739464b61644",
  +  "date": "2022-05-26T12:55:53+01:00",
  +  "path": "/nix/store/bfz0bk523dk4dciiknrzvp87yvnbgcb2-gitsigns.nvim",
  +  "sha256": "04m1767cndrx46xsa6frf77xv64hmr6w21dk2wh4s0sqjvqqm1r6",
     "fetchLFS": false,
     "fetchSubmodules": true,
     "deepClone": false,
  
positive.code: 
    src = fetchgit ( removeAttrs (builtins.fromJSON ''{
    "url": "https://github.com/lua-stdlib/_debug.git",
    "rev": "3236c1561bfc2724a3abd153a6e10c7957b35cf2",
    "date": "2020-04-15T16:34:01-07:00",
    "path": "/nix/store/rgbn0nn7glm7s52d90ds87j10bx20nij-_debug",
    "sha256": "0p6jz6syh2r8qfk08jf2hp4p902rkamjzpzl8xhkpzf8rdzs937w",
    "fetchLFS": false,
    "fetchSubmodules": true,
    "deepClone": false,
  
negative.code:   pname = "lua-term";
    version = "0.7-1";
    knownRockspec = (fetchurl {
      url    = "mirror://luarocks/lua-term-0.7-1.rockspec";
      sha256 = "0r9g5jw7pqr1dyj6w58dqlr7y7l0jp077n8nnji4phf10biyrvg2";
    }).outPath;
    src = fetchurl {
  