In reply to @petrichor:envs.net
flakes are attribute sets with _type = "flake", but when coerced to a string (builtins.toString) or a path (builtins.toPath) they resolve to the flake's store path

In reply to @petrichor:envs.net
i think your overlay could look like final: prev: { unstable = import inputs.unstable { inherit (prev) system config; } but you might get away with omitting system

In reply to @janik0:matrix.org
of course, how else would I get people to do free qa :D

In reply to @ryoschin:matrix.org
When using flakes to manage my system, and having `nixos-unstable` and `home-manager` as inputs, I have to call `sudo nixos-rebuild switch --flake some/path`. Now, that command sometimes downloads around 300 MB of data before actually doing the build (around 150 MB for unstable I suppose, and 148 MB for home-manager). Is it possible to avoid having to wait for that every time? I suppose it might do the downloading when I run `sudo nix-collect-garbage -d` and reboot. (Copied from NixOs, this room might be more suitable for this question)

you can try with --offline then it will try to run any nix * command with the local data from nix cache also stops nix shell and nix run from trying to refresh the remote nix version. Alternatively you can do:

  nix.registry = {
    nixpkgs.flake = inputs.nixpkgs;
  };

that pins any nix * command to the same flake.lock version (similar to what channels or npins or nivs would do for nix-* commands)

In reply to @janik0:matrix.org

you can try with --offline then it will try to run any nix * command with the local data from nix cache also stops nix shell and nix run from trying to refresh the remote nix version. Alternatively you can do:

  nix.registry = {
    nixpkgs.flake = inputs.nixpkgs;
  };

that pins any nix * command to the same flake.lock version (similar to what channels or npins or nivs would do for nix-* commands)

In reply to @janik0:matrix.org

you can try with --offline then it will try to run any nix * command with the local data from nix cache also stops nix shell and nix run from trying to refresh the remote nix version. Alternatively you can do:

  nix.registry = {
    nixpkgs.flake = inputs.nixpkgs;
  };

that pins any nix * command to the same flake.lock version (similar to what channels or npins or nivs would do for nix-* commands)

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 @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...