From 8b1f1d93fa8e3524e0e01378dbe813e6eb06712e Mon Sep 17 00:00:00 2001
From: Linus Heckemann <git@sphalerite.org>
Date: Wed, 12 Jul 2017 22:03:53 +0100
Subject: [PATCH] nixos-install: only search for nixpkgs when needed

---
 nixos/modules/installer/tools/nixos-install.sh | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/installer/tools/nixos-install.sh b/nixos/modules/installer/tools/nixos-install.sh
index 087fbcd4512..7fae915871e 100644
--- a/nixos/modules/installer/tools/nixos-install.sh
+++ b/nixos/modules/installer/tools/nixos-install.sh
@@ -106,8 +106,11 @@ extraBuildFlags+=(--option "build-users-group" "$buildUsersGroup")
 binary_caches="$(@perl@/bin/perl -I @nix@/lib/perl5/site_perl/*/* -e 'use Nix::Config; Nix::Config::readConfig; print $Nix::Config::config{"binary-caches"};')"
 extraBuildFlags+=(--option "binary-caches" "$binary_caches")
 
-nixpkgs="$(readlink -f "$(nix-instantiate --find-file nixpkgs)")"
-export NIX_PATH="nixpkgs=$nixpkgs:nixos-config=$mountPoint/$NIXOS_CONFIG"
+# We only need nixpkgs in the path if we don't already have a system closure to install
+if [[ -z "$closure" ]]; then
+    nixpkgs="$(readlink -f "$(nix-instantiate --find-file nixpkgs)")"
+    export NIX_PATH="nixpkgs=$nixpkgs:nixos-config=$mountPoint/$NIXOS_CONFIG"
+fi
 unset NIXOS_CONFIG
 
 # TODO: do I need to set NIX_SUBSTITUTERS here or is the --option binary-caches above enough?