From d38ceab06dc5fc959b6b3734d0d6a13c9e9a82a1 Mon Sep 17 00:00:00 2001
From: Michael Hudson-Doyle <michael.hudson@canonical.com>
Date: Thu, 12 Dec 2019 12:57:05 +1300
Subject: [PATCH] fix in case of no preferences

---
 live-build/auto/config | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/live-build/auto/config b/live-build/auto/config
index 58c0367b..a4e90059 100755
--- a/live-build/auto/config
+++ b/live-build/auto/config
@@ -1103,7 +1103,9 @@ if [ $PROJECT = ubuntu-base ]; then
 # live-build "helpfully" removes /etc/apt/preferences.d/* so we put a
 # copy somewhere it won't touch it.
 
-cp -a /etc/apt/preferences.d /etc/apt/preferences.d.save
+if [ -n "$(ls -A /etc/apt/preferences.d)" ]; then
+    cp -a /etc/apt/preferences.d /etc/apt/preferences.d.save
+fi
 EOF
 fi