anchor.diff:  # all get the same sources with the same patches applied.
   
   stdenv.mkDerivation rec {
  -  version = "8.9.beta4";
  +  version = "8.9.beta5";
     pname = "sage-src";
   
     src = fetchFromGitHub {
       owner = "sagemath";
       repo = "sage";
       rev = version;
  -    sha256 = "0vvvip5xx0f7h7w0nv82dfkm7jgs79cibb8x2yx7azdc0v7zws69";
  +    sha256 = "1nysal4h108clrf08l8wax25q3agh74l4l327vwm93z9k9c2i6i8";
     };
   
     # Patches needed because of particularities of nix or the way this is packaged.
  
positive.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 = [
      (fetchpatch {
        name = "no-qqbar-timeout-check.patch";
        url = "https://git.sagemath.org/sage.git/patch?id=d5105b625060d4b2a9cfe9cee4316d8b7c96ea46";
        revert = true;
        sha256 = "10dm0yjxdydf1wch5b7gkkkzrc8c8d5hlyascvb9r5pkyr0ak947";
      })
    ];
  
    # 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
  
negative.code:       url = "https://salsa.debian.org/science-team/sagemath/raw/58bbba93a807ca2933ca317501d093a1bb4b84db/debian/patches/dt-version-glpk-4.65-ignore-warnings.patch";
        sha256 = "0b9293v73wb4x13wv5zwyjgclc01zn16msccfzzi6znswklgvddp";
        stripLen = 1;
      })
    ];
  
  