Eval fails with duplicate nix module option when evaluating with lazy-trees #301
Description
Describe the bug
I'm exploring using clan.lol for my homelab. While testing I managed to get into a state where determinate-nix would give me an evaluation error due to a duplicate module option definition. The reported filenames didn't exist so I reran it without lazy-trees and the evaluation succeeded.
Steps To Reproduce
I pushed this config to a branch, you can reproduce it with:
$ nix eval --accept-flake-config github:mrene/dotfiles?ref=lazy-tree-eval-bug#nixosConfigurations.beast.config.system.build.toplevel
error:
… while calling the 'seq' builtin
at «github:NixOS/nixpkgs/c6f52eb»/lib/modules.nix:361:18:
360| options = checked options;
361| config = checked (removeAttrs config [ "_module" ]);
| ^
362| _module = checked (config._module);
… while evaluating a branch condition
at «github:NixOS/nixpkgs/c6f52eb»/lib/modules.nix:297:9:
296| checkUnmatched =
297| if config._module.check && config._module.freeformType == null && merged.unmatchedDefns != [ ] then
| ^
298| let
(stack trace truncated; use '--show-trace' to show the full, detailed trace)
error: The option `sops.gnupg.home' in `/nix/store/546g40c7c4l44rsy0i6wrvipjwybpyis-source/modules/sops' is already declared in `/nix/store/f09v90dfhv2z2cral2vb0i6zv3nrr30y-source/modules/sops'.
$ ls /nix/store/546g40c7c4l44rsy0i6wrvipjwybpyis-source/modules/sops /nix/store/f09v90dfhv2z2cral2vb0i6zv3nrr30y-source/modules/sops
ls: cannot access '/nix/store/546g40c7c4l44rsy0i6wrvipjwybpyis-source/modules/sops': No such file or directory
ls: cannot access '/nix/store/f09v90dfhv2z2cral2vb0i6zv3nrr30y-source/modules/sops': No such file or directory
Disabling lazy-trees:
❯ nix eval --option lazy-trees false --accept-flake-config github:mrene/dotfiles?ref=lazy-tree-eval-bug#nixosConfigurations.beast.config.system.build.toplevel
error: evaluation of cached failed attribute 'nixosConfigurations.beast.config' unexpectedly succeeded
Disabling both lazy-trees and eval-cache:
❯ nix eval --option eval-cache false --option lazy-trees false --accept-flake-config github:mrene/dotfiles?ref=lazy-tree-eval-bug#nixosConfigurations.beast.config.system.build.toplevel
evaluation warning: 'system' has been renamed to/replaced by 'stdenv.hostPlatform.system'
warning: Using 'builtins.toFile' to create a file named 'options.json' that references the store path '/nix/store/h804a5w2y4cqmzkrcgp37m8804ialqi4-source' without a proper context. The resulting file will not have a correct store reference, so this is unreliable and may stop working in the future.
«derivation /nix/store/9apr571q2f4h7l10ywm8j2wdwq21ipp0-nixos-system-beast-25.11.20251215.c6f52eb.drv»
With nix 2.29.1 (through the nixos/nix docker image)
$ nix eval --accept-flake-config --extra-experimental-features "nix-command flakes" github:mrene/dotfiles?ref=lazy-tree-eval-bug#nixosConfigurations.beast.config.system.build.toplevel
«derivation /nix/store/9apr571q2f4h7l10ywm8j2wdwq21ipp0-nixos-system-beast-25.11.20251215.c6f52eb.drv»Expected behavior
Evaluation succeeds, or a clear error message lets me know which module is imported twice.
Metadata
Determinate Nixd daemon version: 3.15.0
Determinate Nixd client version: 3.15.0
You are running the latest version of Determinate Nix.
The following features are enabled:
- lazy-trees
Visit https://dtr.mn/features for more information.
nix (Determinate Nix 3.15.0) 2.33.0
Additional context
Checklist
- checked latest Determinate Nix manual (source)
- checked open bug issues and pull requests for possible duplicates