From 2f5b053b9e337a3fedf2c99a1d1cc69f0dbf30e7 Mon Sep 17 00:00:00 2001
From: r-vdp <ramses@well-founded.dev>
Date: Thu, 23 Apr 2026 09:49:51 +0200
Subject: [PATCH] switch-to-configuration-ng: Document ExecReload reload
 semantics

Update the compare_units doc comment and add a release-notes entry
covering the new reload-instead-of-restart behaviour.
---
 nixos/doc/manual/release-notes/rl-2605.section.md      | 2 ++
 pkgs/by-name/sw/switch-to-configuration-ng/src/main.rs | 7 ++++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/nixos/doc/manual/release-notes/rl-2605.section.md b/nixos/doc/manual/release-notes/rl-2605.section.md
index ed4559794686..a652c7a3657c 100644
--- a/nixos/doc/manual/release-notes/rl-2605.section.md
+++ b/nixos/doc/manual/release-notes/rl-2605.section.md
@@ -347,6 +347,8 @@ See <https://github.com/NixOS/nixpkgs/issues/481673>.
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->
 
+- `switch-to-configuration` now reloads a service instead of restarting it when the only change to its unit is `ExecReload=`, and takes no action when `ExecReload=` is removed. Previously both cases triggered a restart.
+
 - [`hardware.nvidia.branch`](#opt-hardware.nvidia.branch) was added to select the NVIDIA driver branch; setting [`hardware.nvidia.package`](#opt-hardware.nvidia.package) overrides this.
 
 - The NixOS NVIDIA module wiring has been updated to match the new `nvidia-x11` output layout.
diff --git a/pkgs/by-name/sw/switch-to-configuration-ng/src/main.rs b/pkgs/by-name/sw/switch-to-configuration-ng/src/main.rs
index 1085e75674ce..f084f27b9ae2 100644
--- a/pkgs/by-name/sw/switch-to-configuration-ng/src/main.rs
+++ b/pkgs/by-name/sw/switch-to-configuration-ng/src/main.rs
@@ -489,9 +489,10 @@ enum UnitComparison {
 
 // Compare the contents of two unit files and return whether the unit needs to be restarted or
 // reloaded. If the units differ, the service is restarted unless the only difference is
-// `X-Reload-Triggers` in the `Unit` section. If this is the only modification, the unit is
-// reloaded instead of restarted. If the only difference is `Options` in the `[Mount]` section, the
-// unit is reloaded rather than restarted.
+// `X-Reload-Triggers` in the `[Unit]` section, `Options` in the `[Mount]` section, or `ExecReload`
+// in the `[Service]` section, in which case the unit is reloaded rather than restarted. Removing
+// `ExecReload` is treated as a no-op since the running process is unaffected and the new unit can
+// no longer be reloaded.
 fn compare_units(current_unit: &UnitInfo, new_unit: &UnitInfo) -> UnitComparison {
     let mut ret = UnitComparison::Equal;