anchor.diff:  { lib
   , fetchFromGitLab
  -, fetchpatch
   , meson
   , ninja
   , python3
  
positive.code: 
  python3.pkgs.buildPythonApplication rec {
    pname = "gi-docgen";
    version = "2021.2";
  
    format = "other";
  
    src = fetchFromGitLab {
      domain = "gitlab.gnome.org";
      owner = "ebassi";
      repo = pname;
      rev = version;
      sha256 = "17swx4s60anfyyb6dcsl8fq3s0j9cy54qcw0ciq4qj59d4039w5h";
    };
  
    patches = [
      # Add pkg-config file so that Meson projects can find this.
      # https://gitlab.gnome.org/ebassi/gi-docgen/merge_requests/26
      (fetchpatch {
        url = "https://gitlab.gnome.org/jtojnar/gi-docgen/commit/d65ed2e4827c4129d26e3c1df9a48054b4e72c50.patch";
        sha256 = "BEefcHiAd/HTW5zo39J2WtfQjGXUkNFB6MDJj8/Ge80=";
      })
  
      # Name generated devhelp files correctly.
      # https://gitlab.gnome.org/ebassi/gi-docgen/merge_requests/27
      (fetchpatch {
        url = "https://gitlab.gnome.org/ebassi/gi-docgen/commit/7c4de72f55cbce5670c3a6a1451548e97e5f07f7.patch";
        sha256 = "ov/PvrZzKmCzw7nHJkbeLCnhtUVw1UbZQjFrWT3AtVg=";
      })
  
      # Fix broken link in Devhelp TOC.
      # https://gitlab.gnome.org/ebassi/gi-docgen/merge_requests/28
      (fetchpatch {
        url = "https://gitlab.gnome.org/ebassi/gi-docgen/commit/56f0e6f8b4bb9c92d635df60aa5d68f55b036711.patch";
        sha256 = "5gFGiO9jPpkyZBL4qtWEotE5jY3sCGFGUGN/Fb6jZ+0=";
      })
  
      # Devhelp does not like subsections without links.
      # https://gitlab.gnome.org/GNOME/devhelp/-/issues/28
      (fetchpatch {
        # Only visual but needed for the other two to apply.
        # https://gitlab.gnome.org/ebassi/gi-docgen/merge_requests/28
        url = "https://gitlab.gnome.org/ebassi/gi-docgen/commit/7f67fad5107b73489cb7bffca49177d9ad78e422.patch";
        sha256 = "OKbC690nJsl1ckm/y9eeKDYX6AEClsNvIFy7DK+JYEc=";
      })
      # Add links to index.
      (fetchpatch {
        url = "https://gitlab.gnome.org/ebassi/gi-docgen/commit/f891cc5fd481bc4180eec144d14f32c15c91833b.patch";
        sha256 = "Fcnvdgxei+2ulGoWoCZ8WFrNy01tlNXMkHru3ArGHVQ=";
      })
      # Use different link for each symbol type name.
      # https://gitlab.gnome.org/ebassi/gi-docgen/merge_requests/29
      (fetchpatch {
        url = "https://gitlab.gnome.org/jtojnar/gi-docgen/commit/08dcc31f62be1a5af9bd9f8f702f321f4b5cffde.patch";
        sha256 = "vAT8s7zQ9zCoZWK+6PsxcD5/48ZAfIOl4RSNljRCGWQ=";
      })
      # make DevHelp sections & index.json have stable ordering
      # already merged upstream, so patch can removed when we update
      # beyond 2021.2
      (fetchpatch {
        url = "https://gitlab.gnome.org/GNOME/gi-docgen/-/commit/cc21241d4386d4f78dbcb087fd9a92899935cb5c.patch";
        sha256 = "0wna8mzrlbsv7f3bc7ndqll9l105kp8kdmhbbjhbdhzzzyvh6vcw";
      })
    ];
  
    nativeBuildInputs = [
      meson
  
negative.code: 
    meta = with lib; {
      description = "Documentation generator for GObject-based libraries";
      homepage = "https://gitlab.gnome.org/GNOME/gi-docgen";
      license = licenses.asl20; # OR GPL-3.0-or-later
      maintainers = teams.gnome.members;
    };
  