How to efficiently iterate while developing a flake input

[TLATER]

@enne

I guess I have a lot more reading to do, as it’s unclear to me how to do this in my flake.nix. Most flakes seem to be providing apps that are sourced from the flake itself and not an executable that comes from some other package. Documentation on apps seems fairly slim. Do you have any pointers to better documentation or tutorials I should be looking at?

Yeah, this is a pattern I often use, but the apps feature in general is probably still a bit unexplored in the community. You probably won’t see many examples yet. They also tend to be a bit on the explicit side, which looks ugly in a flake.nix so people probably hide them behind imports a lot.

There’s no convenient little method to create mini-apps from a package yet, but the principle is the same as with making one from packages created within the flake - it’s all just derivations after all.

Here’s an example where I run my web server with the corresponding HTML templates to do a full integration test for my web server: tlaternet-webserver/flake.nix at master - tlaternet/tlaternet-webserver - Forgejo: Beyond coding. We Forge.

In your case, you’d probably do something like this:

{
  description = "tlater.net web server";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
  };

  outputs = { self, nixpkgs, ... }: let
    system = "x86_64-linux";
    pkgs = nixpkgs.legacyPackages.${system};
  in {
    # I have no idea how to inject a plugin into vim from the command line
    # Naturally, you can .override the `pkgs.neovim` instead if needed, and
    # that *would* make importing it from a separate file tempting.
    apps.${system}.testvim = pkgs.writeShellScript "testvim" ''
      ${pkgs.neovim}/bin/vim --plugin ${self.packages.${system}.vim-plugin}
    '';
  };