From ecb6d13253194b16bd47cd4e3defc49d80be4505 Mon Sep 17 00:00:00 2001
From: Ismo Puustinen <ismo.puustinen@intel.com>
Date: Tue, 5 Mar 2019 18:34:10 +0200
Subject: [PATCH] hack/lib/util.sh: fix empty array expansion with bash 3.

---
 hack/lib/util.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hack/lib/util.sh b/hack/lib/util.sh
index c820206d8ee..31ce9fc4a72 100755
--- a/hack/lib/util.sh
+++ b/hack/lib/util.sh
@@ -649,7 +649,9 @@ EOF
 # Determines if docker can be run, failures may simply require that the user be added to the docker group.
 function kube::util::ensure_docker_daemon_connectivity {
   IFS=" " read -ra DOCKER <<< "${DOCKER_OPTS}"
-  DOCKER=(docker "${DOCKER[@]}")
+  # Expand ${DOCKER[@]} only if it's not unset. This is to work around
+  # Bash 3 issue with unbound variable.
+  DOCKER=(docker ${DOCKER[@]:+"${DOCKER[@]}"})
   if ! "${DOCKER[@]}" info > /dev/null 2>&1 ; then
     cat <<'EOF' >&2
 Can't connect to 'docker' daemon.  please fix and retry.