How to build this with aria2

woodenAllen · May 11, 2025, 7:21pm

NixOS/nixpkgs/blob/1750f3c1c89488e2ffdd47cab9d05454dddfb734/pkgs/by-name/ug/uget/package.nix#L63


      
            ])
            ++ (lib.optional (aria2 != null) aria2);
          
          enableParallelBuilding = true;
          
          preFixup = lib.optionalString (
            aria2 != null
          ) ''gappsWrapperArgs+=(--suffix PATH : "${aria2}/bin")'';
          
          meta = with lib; {
            description = "Download manager using GTK and libcurl";
            longDescription = ''
              uGet is a VERY Powerful download manager application with a large
              inventory of features but is still very light-weight and low on
              resources, so don't let the impressive list of features scare you into
              thinking that it "might be too powerful" because remember power is good
              and lightweight power is uGet!
            '';
            homepage = "http://www.ugetdm.com";
            license = licenses.lgpl21;
            platforms = platforms.unix;

I just put:

home.packages = [(pkgs.uget.override {
    aria2 = true;
})];

But it doesn’t build.

AndersonTorres · May 11, 2025, 7:47pm

IIRC aria2 should be set to pkgs.aria2.

But this is even worse.

A long time ago, Nixpkgs expressions employed a “package-or-null” convention in order to establish a package as optional.
However, it is too error-prone, because the interactions between null and other expressions are unexpected.
It happened a lot when I refactored Emacs.
(And, incidentally, it happened to you right now…)

The cleaner way to do this is use a Boolean guard, say ariaSupport, and use it to control the inclusion of dependencies.

BTW Uget fixup by AndersonTorres · Pull Request #406261 · NixOS/nixpkgs · GitHub