Nixos-rebuild aggressively caching previous attempts

Help
1

I have a very frustrating issue.

First off I’m a nixos newbie.

Second, an explanation of how I got here:

I was trying to configure Redshift (you know the screen color and brightness tool) and I wanted to create a module that would have some hard-coded values, of my current location (latitude and longitude) so it would be able to be used in my multiple of my system (hosts).

So I would end up using something like:

    services.redshift = {
      enable = true;
      temperature.day = cfg.temperature.day;
      temperature.night = cfg.temperature.night;
      brightness.day = cfg.brightness.day;
      brightness.night = cfg.brightness.night;
      extraOptions = [
        "-l ${glbInfo.location.latitude}:${glbInfo.location.longitude}"
        "-l manual"
      ];
    };

I know that the provided info is not enough on why my attempts to have ${glbInfo.location.XXXX} properly expand, but that is not the issue.

Any attempt to run sudo nixos-rebuild switch --flake .#myhost would fail with:

...
...
         at /nix/store/5acdh8xyry0kdvp6xla2hw7wf3zkphkl-source/lib/attrsets.nix:742:20:

          741|               then recurse (path ++ [name]) value
          742|               else f (path ++ [name]) value;
             |                    ^
          743|         in mapAttrs g;

       … while calling anonymous lambda

         at /nix/store/5acdh8xyry0kdvp6xla2hw7wf3zkphkl-source/lib/modules.nix:242:72:

          241|           # For definitions that have an associated option
          242|           declaredConfig = mapAttrsRecursiveCond (v: ! isOption v) (_: v: v.value) options;
             |                                                                        ^
          243|

       … while evaluating the option `location.latitude':

       error: The option `location.latitude' is used but not defined.

This probably requires another post to figure out why, but again that’s not my question yet.

After giving up, on globally defined these variables, I deleted the module that defined them and redited the redshift file to a plainer:

    services.redshift = {
      enable = true;
      temperature.day = cfg.temperature.day;
      temperature.night = cfg.temperature.night;
      brightness.day = cfg.brightness.day;
      brightness.night = cfg.brightness.night;
      extraOptions = [
        "-l 40.68:-3.68"
        "-l manual"
      ];
    };

I committed the changes to the git repo to make sure that everything is neat, but now trying again to switch to the new version I still get:

       … while evaluating the option `location.latitude':

       error: The option `location.latitude' is used but not defined.

There is absolutely no mention of location.latitude or even latitude in any of my source files.

nixos-rebuild keeps insisting that the “option is used but not defined”

Things I have tried:

  • rm -rf ~/.cache/nix
  • sudo rm -rf /root/.cache/nix
  • nix-garbage-collect
  • nix-garbage-collect -d
  • sudo nixos-rebuild switch --rollback (thinking maybe if I start from previous version, less things would be cached)
  • rebooting multiple times between tries

I just cannot get passed this error.

Not sure if it helps but nix flake check also fails with the same error.

I’m getting crazy. Help…?

2

Nixpkgs already has that option, and you need to set it to get the redshift module to work: https://search.nixos.org/options?channel=23.11&show=location.longitude&from=0&size=50&sort=relevance&type=packages&query=location.

3

Oh. My. God!

The location.latitude does not refer to my “failed” attempts to define my own lat/long, but an already existing builtin location offered by nixos!

What an unfortunate name collision! I would have never thought of searching for a similarly named variable! I only wish I had tried naming my variables as currentLocation or something so that I would be able to spot the difference.

Thanks! Sanity reverted!

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