From 1b9d7745f4af604225f3ab831ba1c2a6f424eed5 Mon Sep 17 00:00:00 2001
From: Jakob Lechner <mail@jalr.de>
Date: Tue, 28 May 2024 20:28:15 +0200
Subject: [PATCH] Add upgrade-diff

---
 modules/default.nix      |  1 +
 modules/upgrade-diff.nix | 14 ++++++++++++++
 2 files changed, 15 insertions(+)
 create mode 100644 modules/upgrade-diff.nix

diff --git a/modules/default.nix b/modules/default.nix
index e5fc8af..dbb9ab1 100644
--- a/modules/default.nix
+++ b/modules/default.nix
@@ -49,6 +49,7 @@
     ./udmx.nix
     ./uefi.nix
     ./unfree.nix
+    ./upgrade-diff.nix
     ./wireshark.nix
     ./yubikey-gpg.nix
   ];
diff --git a/modules/upgrade-diff.nix b/modules/upgrade-diff.nix
new file mode 100644
index 0000000..ccdbe4c
--- /dev/null
+++ b/modules/upgrade-diff.nix
@@ -0,0 +1,14 @@
+# MIT Jörg Thalheim - https://github.com/Mic92/dotfiles/blob/c6cad4e57016945c4816c8ec6f0a94daaa0c3203/nixos/modules/upgrade-diff.nix
+{ config, pkgs, ... }:
+{
+  system.activationScripts.diff = {
+    supportsDryActivation = true;
+    text = ''
+      if [[ -e /run/current-system ]]; then
+        echo "--- diff to current-system"
+        ${pkgs.nvd}/bin/nvd --nix-bin-dir=${config.nix.package}/bin diff /run/current-system "$systemConfig"
+        echo "---"
+      fi
+    '';
+  };
+}