In reply to @ryoschin:matrix.org
But my problem is in that sudo nix-collect-garbage -d deletes the sources, and sudo nixos-rebuild switch --flake some/path has to download them again (I suppose that is because they count as cache, so it clears them). I need the gc to not clear them, and the rebuild command to re-download them only if there is an actual update

In reply to @2xsaiko:tchncs.de
if you add those flakes to the local registry then they will not be collected
alternatively I guess you can add them to system.extraDependencies

In reply to @janik0:matrix.org
There was some setting like keepDerivations or something to prevent that but I'm not at my laptop currently.

In reply to @ryoschin:matrix.org
So, as far as I can tell now, all I need to do is make the flake a GC root, right? So, how do I do that...

In reply to @ryoschin:matrix.org
I see. Mind sharing the process?

In reply to @peacememories:matrix.org
i've been looking into this again after some time away, and still can't really find anything:
is there a way to exclude one directory from my flake? specifically we have a giant folder of reference PDFs checked into our source tree, and copying them every time a flake is built makes our development shell unusable.
this is why we're currently running non-flake nix, but I would love to be able to switch

Everyone seems to do this differently. I have this for building NixOS configs.

{ self, nixpkgs, ... }:
(nixpkgs.lib.mapAttrs'
  (name: config: nixpkgs.lib.nameValuePair name config.config.system.build.toplevel)
  self.nixosConfigurations
)

But not sure if this actually works, or if I configured the jobs manually in hydra...

hmm, is there a more elegant solution for adding overlays in a flake than

pkgs = import nixpkgs {
        inherit system;
        overlays = [
          poetry2nix.overlay
        ];
      };

or is this just how it's done?

In reply to @wucke13:matrix.org
What is a nice way to fill hydraJobs with the packages and checks of a flake?

    hydraJobs = {
      inherit (self) checks packages;
    };

In reply to @wucke13:matrix.org
but formally packages are system.attr, while hydraJobs is attr.system