Can't update because of an opaque KDE Plasma 5 dependency on Plasma 6 configuration

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1

Hello, the issue I’m experiencing is the following:

Using my flake-based nixos config I’ve run sudo nix flake update --flake /etc/nixos to update the inputs (I’m using the nixos-unstable repo) and then I’ve run sudo nixos-rebuild switch as I usually did to update my system and after updating the system config. I’ve got an error message that I can’t find referenced anywhere and since I’m using Plasma 6, and I’m not explicitly adding extra-cmake-modules in my environment.systemPackages and neither do I explicitly add environment.etc.dbus-1.source, it makes little sense to me. The error message that sudo nixos-rebuild switch gave is:

$ sudo nixos-rebuild boot
building the system configuration…
error:
… while calling the ‘derivationStrict’ builtin
at «nix-internal»/derivation-internal.nix:37:12:
36|
37|   strict = derivationStrict drvAttrs;
|            ^
38|

   … while evaluating derivation 'nixos-system-sharccnix-26.05.20260515.d233902'
     whose name attribute is located at «github:nixos/nixpkgs/d233902339c02a9c334e7e593de68855ad26c4cb?narHash=sha256-30sZNZoA1cqF5JNO9fVX%2BwgiQYjB7HJqqJ4ztCDeBZE%3D»/pkgs/stdenv/generic/make-derivation.nix:618:11

   … while evaluating attribute 'buildCommand' of derivation 'nixos-system-sharccnix-26.05.20260515.d233902'
     at «github:nixos/nixpkgs/d233902339c02a9c334e7e593de68855ad26c4cb?narHash=sha256-30sZNZoA1cqF5JNO9fVX%2BwgiQYjB7HJqqJ4ztCDeBZE%3D»/nixos/modules/system/activation/top-level.nix:64:7:
       63|       passAsFile = [ "extraDependencies" ];
       64|       buildCommand = systemBuilder;
         |       ^
       65|

   … while evaluating the option `environment.etc.dbus-1.source':

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

   error: The libsForQt5.extra-cmake-modules package and the corresponding top-level extra-cmake-modules alias have been removed, as KDE Gear 5 and Plasma 5 have reached end of life.
   Please explicitly use kdePackages.extra-cmake-modules for the latest Qt 6-based version.

Command ‘nix --extra-experimental-features ‘nix-command flakes’ build --print-out-paths ‘/etc/nixos#nixosConfigurations.“sharccnix”.config.system.build.toplevel’ --no-link’ returned non-zero exit status 1.

I assume one of the packages declared in the configuration is dependent on Plasma 5 version of extra-cmake-modules, which is EoL, but I don’t know how it’s possible to figure that out, which one that is. Note: adding kdePackages.extra-cmake-modules to environment.systemPackages as stated in the error message made no difference.

I can post relevant parts of my configuration if needed.

Also I would note that I’m very new to nixos and this might be an issue with an obvious solution that I just couldn’t found. Any help would be appreciated.

2

Is your config stored somewhere public? It will be very difficult to diagnose without that.

3

I’ve found the source of the issue, it’s an issue with a third-party flake, I will close this issue now

I would still love to know the way of finding the cause of it without trying and testing every flake or package that I have in my configuration if something similar happens again, since the error message didn’t give me any indication of a possible culprit

1 Like
4

It can sometimes help to try --show-trace as the error message suggested. You do have to learn to scan the output though because it tends to be quite verbose.

The command nix-option can be another useful diagnostic tool to identify where a certain option is set from, although it tends to require a config that can successfully evaluate.

Hierarchical and modular configs can also sometimes turn “testing every flake or package” into more of a bisection than a linear search.