Feature Request: NixOS support for updates module

[KaiStarkk]

Problem

NixOS has no pacman -Qu equivalent. nixos-rebuild dry-run --upgrade shows derivation changes, not package versions.

Solution

I've built a tool that handles this: https://github.com/KaiStarkk/nixup

Approach:

• One-time nixpkgs evaluation → local index (~17MB, ~5s)
• Scans system closure for installed packages
• Instant local version comparisons (no API dependency)
• Lockfile prevents parallel updates to the cache

Output:
nixup updates count # → 63
nixup updates tooltip # → formatted tooltip with package list
nixup updates list # → full list with versions

Tooltip format:
9 updates available

• hyprbars 0.1 → 0.52.0
• qtbase 5.15.18 → 6.10.1
  ... and 4 others

Status bar features:

• count shows ⟳ during refresh
• tooltip shows progress bar during refresh: ████░░░░░░ (250/500)
• open launches terminal with update list (uses $TERMINAL)

Integration

Two options:

1. Minimal: Detect NixOS, call nixup updates count for badge, nixup updates tooltip for hover
2. Full: Native dropdown with package list via nixup updates list

Happy to contribute a PR. Tool is MIT licensed.