How to troubleshoot/diff channel upgrades?

[wamserma]

You can use nvd and nix-diff to see what changed on your system:

Nvd: Simple Nix/NixOS version diff tool

Thanks @madjar ! In my case (just nix + home-manager on a non-NixOS, report-switching not needed) it boiled down to: { config, pkgs, lib, ... }: with lib; let dag = config.lib.dag; nvd = import (pkgs.fetchFromGitLab { owner = "khumba"; repo = "nvd"; rev = "7cdaa6d818119bd7a51930d990fded5d594c6623"; sha256 = "sha256-dQcfoMtRGg+SRvgY9pbSqlyeTozlHp3qE70egSEiFX0="; }) { inherit pkgs; }; in { home.activation.report-changes = dag.entryAnywhere '' ${nvd}/bin/nvd $oldGenP…