error:
       … while calling the 'derivationStrict' builtin
         at «nix-internal»/derivation-internal.nix:37:12:
           36|
           37|   strict = derivationStrict drvAttrs;
             |            ^
           38|

       … while evaluating derivation 'nix-shell'
         whose name attribute is located at «git+https://github.com/NixOS/nixpkgs?ref=nixpkgs-unstable&rev=6b5e5b7a6631f065bf6908986990b37d845f847f&shallow=1»/pkgs/stdenv/generic/make-derivation.nix:651:11

       … while evaluating attribute 'buildInputs' of derivation 'nix-shell'
         at «git+https://github.com/NixOS/nixpkgs?ref=nixpkgs-unstable&rev=6b5e5b7a6631f065bf6908986990b37d845f847f&shallow=1»/pkgs/stdenv/generic/make-derivation.nix:722:11:
          721|           depsHostHost = hostHostOutputs;
          722|           buildInputs = hostTargetOutputs;
             |           ^
          723|           depsTargetTarget = targetTargetOutputs;

       … while evaluating definitions from `/nix/store/cxha84prddcnk4v2d234riyghkspqzp6-source/machines/build01/terraform-configuration.nix':

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

       error: attribute 'zerotier' missing
       at «git+file:///var/lib/nixbot/worktrees/8-d16ef3f64524-216?rev=f9a9fd913390c90bbc707d5b07b59875d4c7a6d2»/machines/build01/terraform-configuration.nix:28:12:
           27|         inherit
           28|           (self.nixosConfigurations.build01.config.clan.core.vars.generators.zerotier.files.zerotier-ip)
             |            ^
           29|           value