Bug: Hardcoded /bin/mkdir and /bin/ln paths fail on NixOS

[rhnvrm]

Description

The home-manager module uses hardcoded paths /bin/mkdir and /bin/ln in activation scripts, which don't exist on NixOS. On NixOS, these binaries are located at /run/current-system/sw/bin/.

Environment

• NixOS 24.11 (unstable)
• nix-clawdbot (latest from main branch)
• Deployed via nixos-anywhere to Hetzner Cloud

Error

During home-manager activation (as part of nixos-rebuild switch):

/nix/store/c23s6r3g3xv3gwyg42smqkxydccy0ghq-home-manager-generation/activate: line 276: /bin/mkdir: No such file or directory

Affected Code

In nix/modules/home-manager/clawdbot.nix, the activation scripts use hardcoded paths:

home.activation.clawdbotDirs = lib.hm.dag.entryAfter [ "writeBoundary" ]
  '/bin/mkdir -p ...'

home.activation.clawdbotConfigFiles = ...
  '/bin/ln -sfn ...'

Workaround

Create symlinks manually on the NixOS host before running home-manager:

sudo mkdir -p /bin
sudo ln -sf /run/current-system/sw/bin/mkdir /bin/mkdir
sudo ln -sf /run/current-system/sw/bin/ln /bin/ln

Suggested Fix

Replace hardcoded paths with the home-manager $DRY_RUN_CMD convention which handles PATH correctly:

home.activation.clawdbotDirs = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
  $DRY_RUN_CMD mkdir -p ...
'';

home.activation.clawdbotConfigFiles = ... ''
  $DRY_RUN_CMD ln -sfn ...
'';

Alternatively, use explicit nix store paths:

home.activation.clawdbotDirs = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
  ${pkgs.coreutils}/bin/mkdir -p ...
'';

Both approaches are portable across NixOS, macOS, and traditional Linux distributions.

[zenware]

The correct way to solve this problem per home-manager: https://nix-community.github.io/home-manager/options.xhtml#opt-home.activation

Is to prefix commands with run in a home-manager activation context. Which also has the benefit of respecting env vars like DRY_RUN=1 or flags like --verbose

I've been trying to build a check that runs on nix flake check or which runs in the CI that can clearly show as a pair of two commits, that the issue exists in the activation stage, and that a change to run mkdir solves it... But for some reason it's been really tricky to get the activation scripts to trigger unless actually building and running (e.g. home-manager switch)

🤞 hoping the project maintainer can find a weekend to review some of these PRs