From b35fe01f025fdbc0c0ca9352583b685ead6e3b10 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 16 Jan 2013 14:40:41 +0100
Subject: [PATCH] Set the NixOS version to something useful when building from
 Git

---
 modules/installer/tools/nixos-rebuild.sh | 10 ++++++++++
 modules/misc/version.nix                 | 17 ++++++++++++-----
 release.nix                              |  4 ++--
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/modules/installer/tools/nixos-rebuild.sh b/modules/installer/tools/nixos-rebuild.sh
index 0b149610e324..28a1d2282939 100644
--- a/modules/installer/tools/nixos-rebuild.sh
+++ b/modules/installer/tools/nixos-rebuild.sh
@@ -140,6 +140,16 @@ if [ -n "$buildNix" ]; then
 fi
 
 
+# Update the version suffix if we're building from Git (so that
+# nixos-version shows something useful).
+if nixos=$(nix-instantiate --find-file nixos "${extraBuildFlags[@]}"); then
+    suffix=$($SHELL $nixos/modules/installer/tools/get-version-suffix "${extraBuildFlags[@]}")
+    if [ -n "$suffix" ]; then
+        echo -n "$suffix" > "$nixos/.version-suffix"
+    fi
+fi
+
+
 # Either upgrade the configuration in the system profile (for "switch"
 # or "boot"), or just build it and create a symlink "result" in the
 # current directory (for "build" and "test").
diff --git a/modules/misc/version.nix b/modules/misc/version.nix
index 319cdcb5f98f..23e96171d1fe 100644
--- a/modules/misc/version.nix
+++ b/modules/misc/version.nix
@@ -5,18 +5,25 @@ with pkgs.lib;
 {
 
   options = {
-  
+
     system.nixosVersion = mkOption {
-      default =
-        builtins.readFile ../../.version
-        + (if builtins.pathExists ../../.version-suffix then builtins.readFile ../../.version-suffix else "pre-git");
       description = "NixOS version.";
     };
 
+    system.nixosVersionSuffix = mkOption {
+      description = "NixOS version suffix.";
+    };
+
   };
 
   config = {
 
+    system.nixosVersion =
+      builtins.readFile ../../.version + config.system.nixosVersionSuffix;
+
+    system.nixosVersionSuffix =
+      if builtins.pathExists ../../.version-suffix then builtins.readFile ../../.version-suffix else "pre-git";
+
     # Generate /etc/os-release.  See
     # http://0pointer.de/public/systemd-man/os-release.html for the
     # format.
@@ -32,7 +39,7 @@ with pkgs.lib;
           '';
         target = "os-release";
       };
-  
+
   };
 
 }
diff --git a/release.nix b/release.nix
index 4c29fce29f29..6caf3b385b16 100644
--- a/release.nix
+++ b/release.nix
@@ -20,7 +20,7 @@ let
     let
 
       versionModule =
-        { system.nixosVersion = version + (lib.optionalString (!officialRelease) versionSuffix);
+        { system.nixosVersionSuffix = lib.optionalString (!officialRelease) versionSuffix;
           isoImage.isoBaseName = "nixos-${type}";
         };
 
@@ -55,7 +55,7 @@ let
 
     with import <nixpkgs> {inherit system;};
     let
-      versionModule = { system.nixosVersion = version + (lib.optionalString (!officialRelease) versionSuffix); };
+      versionModule = { system.nixosVersionSuffix = lib.optionalString (!officialRelease) versionSuffix; };
 
       config = (import lib/eval-config.nix {
         inherit system;