error: access to absolute path '/nix/store/secrets' is forbidden in pure evaluation mode

After upgrading my flake recently I started getting errors like:

       … while evaluating the option `system.build.toplevel':

       … while evaluating definitions from `/nix/store/z71lmgd0ydfnax1b13zbrls5idf1y7ak-source/nixos/modules/system/activation/top-level.nix':

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

       error: access to absolute path '/nix/store/secrets' is forbidden in pure evaluation mode (use '--impure' to override)

After reading a previous issue here (#98) and trying a debug session with the graceful help of a fellow snowfall user, that is summarized in a completely different repo (https://github.com/Mic92/sops-nix/issues/569) I am still facing issues not being able to make the suggested fix work, as I keep getting the same error while using lib.snowfall.fs.get-file or not.

My pushed changes that keep failing are in: https://gitlab.com/stratosgear/ultragear/-/tree/snowfall-get-file-error?ref_type=heads

Would you have any suggestions on how to proceed from here...?

Thanks!

Start by reproducing the pure-evaluation error from the linked snowfall-get-file-error branch, then compare the behavior with issue #98 and sops-nix issue #569. The report names lib.snowfall.fs.get-file but no repository file or test; done would require identifying why the absolute path is accessed and documenting or implementing a verified resolution.