From b2abfe54b3da8eddda3135561c0c841c3023966d Mon Sep 17 00:00:00 2001
From: "Nicolas B. Pierron" <nicolas.b.pierron@gmail.com>
Date: Fri, 19 Dec 2014 23:00:00 +0100
Subject: [PATCH] nixos-option: Print derivation outPath within attribute sets
 and list, when the strict mode is used.

---
 nixos/modules/installer/tools/nixos-option.sh | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/nixos/modules/installer/tools/nixos-option.sh b/nixos/modules/installer/tools/nixos-option.sh
index a2b963d7661..b5f69f07826 100644
--- a/nixos/modules/installer/tools/nixos-option.sh
+++ b/nixos/modules/installer/tools/nixos-option.sh
@@ -76,14 +76,23 @@ evalAttr(){
   local prefix="$1"
   local strict="$2"
   local suffix="$3"
+
+  # If strict is set, then set it to "true".
+  test -n "$strict" && strict=true
+
   evalNix ${strict:+--strict} <<EOF
 let
   reach = attrs: attrs${option:+.$option}${suffix:+.$suffix};
   nixos = import <nixos> {};
   nixpkgs = import <nixpkgs> {};
+  strict = ${strict:-false};
   cleanOutput = x: with nixpkgs.lib;
     if isDerivation x then x.outPath
     else if isFunction x then "<CODE>"
+    else if strict then
+      if isAttrs x then mapAttrs (n: cleanOutput) x
+      else if isList x then map cleanOutput x
+      else x
     else x;
 in
   cleanOutput (reach nixos.$prefix)