From 3351e1b562741fa08736ccfb244c34c5a86a54c7 Mon Sep 17 00:00:00 2001
From: Michael Hoang <enzime@users.noreply.github.com>
Date: Sun, 19 Jan 2025 14:34:30 +1100
Subject: [PATCH] detect-hostname-change: improve installer detection

---
 nixos/common/detect-hostname-change.nix | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/nixos/common/detect-hostname-change.nix b/nixos/common/detect-hostname-change.nix
index 7ced2ef6..7fe061f7 100644
--- a/nixos/common/detect-hostname-change.nix
+++ b/nixos/common/detect-hostname-change.nix
@@ -13,13 +13,16 @@
 
   config = lib.mkIf (config.srvos.detect-hostname-change.enable && config.networking.hostName != "") {
     system.preSwitchChecks.detectHostnameChange = ''
+      actual=$(< /proc/sys/kernel/hostname)
+
       # Ignore if the system is getting installed
-      if [[ ! -e /run/current-system ]]; then
+      # https://github.com/nix-community/nixos-images/blob/2fc023e024c0a5e8e98ae94363dbf2962da10886/nix/installer.nix#L12-L13
+      if [[ ! -e /run/booted-system || "$actual" == "nixos-installer" ]]; then
         exit
       fi
 
-      actual=$(< /proc/sys/kernel/hostname)
       desired=${config.networking.hostName}
+
       if [[ "$actual" = "$desired" ]]; then
         exit
       fi