From 2547e0e96aa7923b18826f9fe71d0d107e5faf90 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Fri, 20 Jul 2012 15:41:37 -0400
Subject: [PATCH] systemd: Use an interface version, just like we have for
Upstart
---
pkgs/os-specific/linux/systemd/default.nix | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/pkgs/os-specific/linux/systemd/default.nix b/pkgs/os-specific/linux/systemd/default.nix
index dbf877ebaeb..a6889e3e440 100644
--- a/pkgs/os-specific/linux/systemd/default.nix
+++ b/pkgs/os-specific/linux/systemd/default.nix
@@ -70,6 +70,14 @@ stdenv.mkDerivation rec {
enableParallelBuilding = true;
+ # The interface version prevents NixOS from switching to an
+ # incompatible systemd at runtime. (Switching across reboots is
+ # fine, of course.) It should be increased whenever systemd changes
+ # in a backwards-incompatible way. If the interface version of two
+ # systemd builds is the same, then we can switch between them at
+ # runtime; otherwise we can't and we need to reboot.
+ passthru.interfaceVersion = 2;
+
meta = {
homepage = http://www.freedesktop.org/wiki/Software/systemd;
description = "A system and service manager for Linux";