From e48fe612e22aeac96e6fc56fdcda9b09e66848eb Mon Sep 17 00:00:00 2001
From: teutat3s <teutates@mailbox.org>
Date: Mon, 11 Nov 2024 18:02:47 +0100
Subject: [PATCH] core: add activationScript to show closure diff

This is useful when updating a host, by doing a dry-run with deploy-rs
we get a list of changed package versions.
---
 modules/core/nix.nix | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/modules/core/nix.nix b/modules/core/nix.nix
index 8640ec7..eca6351 100644
--- a/modules/core/nix.nix
+++ b/modules/core/nix.nix
@@ -11,6 +11,17 @@
     permittedInsecurePackages = [ "olm-3.2.16" ];
   };
 
+  system.activationScripts.diff-closures = {
+    text = ''
+      if [[ -e /run/current-system ]]; then
+        ${config.nix.package}/bin/nix store diff-closures \
+          /run/current-system "$systemConfig" \
+          --extra-experimental-features nix-command
+      fi
+    '';
+    supportsDryActivation = true;
+  };
+
   nix = {
     # Use default version alias for nix package
     package = pkgs.nix;