anchor.diff:        url = "https://salsa.debian.org/science-team/sagemath/raw/58bbba93a807ca2933ca317501d093a1bb4b84db/debian/patches/dt-version-glpk-4.65-ignore-warnings.patch";
         sha256 = "0b9293v73wb4x13wv5zwyjgclc01zn16msccfzzi6znswklgvddp";
         stripLen = 1;
  -    })
  -
  -    # https://trac.sagemath.org/ticket/26932
  -    (fetchSageDiff {
  -      name = "givaro-4.1.0_fflas-ffpack-2.4.0_linbox-1.6.0.patch";
  -      base = "8.8.beta4";
  -      rev = "c11d9cfa23ff9f77681a8f12742f68143eed4504";
  -      sha256 = "0xzra7mbgqvahk9v45bjwir2mqz73hrhhy314jq5nxrb35ysdxyi";
       })
     ];
   
  
positive.code: # all get the same sources with the same patches applied.
  
  stdenv.mkDerivation rec {
    version = "8.9.beta4";
    pname = "sage-src";
  
    src = fetchFromGitHub {
      owner = "sagemath";
      repo = "sage";
      rev = version;
      sha256 = "0vvvip5xx0f7h7w0nv82dfkm7jgs79cibb8x2yx7azdc0v7zws69";
    };
  
    # Patches needed because of particularities of nix or the way this is packaged.
  
negative.code:   # Since sage unfortunately does not release bugfix releases, packagers must
    # fix those bugs themselves. This is for critical bugfixes, where "critical"
    # == "causes (transient) doctest failures / somebody complained".
    bugfixPatches = [ ];
  
    # Patches needed because of package updates. We could just pin the versions of
    # dependencies, but that would lead to rebuilds, confusion and the burdons of
  