How do I install a package from a derivation?

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1

Hello! I am trying to install a particular version of the ‘gummy’ package (I have some scripts that rely on new features and the Nixpkgs version is too old). There is a pull request that could update it, but it’s been largely ignored for months by the package maintainer, so I’m looking for a short-term quick (local) and simple/easy solution until that gets fixed.

I’m thinking that the easiest way to do it is to use the derivation from the pull request, which is can be found here.

I don’t have a lot of experience with Nix right now (I got NixOS up and running with a template and a few basic options), so I don’t know how to do this. Please help me install this package. I don’t care if it’s not the “right” way to do it, if it’s imperative, impure etc - I’ll learn the language and redo it the right way if necessary, but now I have to get this thing working. Thank you!

For context, if necessary, this is my current NixOS configuration.

2

If you copied the default.nix from the PR you can install it by putting (pkgs.callPackage ./path/to/default.nix {}) (or just . instead of default.nix) in NixOS’ environment.systemPackages or Home Manager’s home.packages.

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3

I just tried that and I get the following error messages:

error:
       … while calling the 'head' builtin

         at /nix/store/3kwj19dbdfxnjbcns4hw307ylhz3wgrm-source/lib/attrsets.nix:1541:11:

         1540|         || pred here (elemAt values 1) (head values) then
         1541|           head values
             |           ^
         1542|         else

       … while evaluating the attribute 'value'

         at /nix/store/3kwj19dbdfxnjbcns4hw307ylhz3wgrm-source/lib/modules.nix:809:9:

          808|     in warnDeprecation opt //
          809|       { value = builtins.addErrorContext "while evaluating the option `${showOption loc}':" value;
             |         ^
          810|         inherit (res.defsFinal') highestPrio;

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: getting status of '/nix/store/rq8zsd36v1rzrfbvadlqqmlsgmphz63x-source/hosts/hermes/gummy.nix': No such file or directory
4

Are you using Flakes? If so you will need to git add /path/to/gummy.nix first.

5

That fixed it! Thank you! I forgot that it was necessary to do that when using flakes.

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