From c568e9059c5c713604570ba8deba19eaccd76284 Mon Sep 17 00:00:00 2001
From: Dave Reisner <dreisner@archlinux.org>
Date: Sat, 6 Oct 2018 19:57:43 -0400
Subject: [PATCH] common: avoid calling umount without any args

For example, when calling arch-chroot on a dir without a /proc:

  # arch-chroot badroot
  mount: badroot/proc: mount point does not exist.
  ==> ERROR: failed to setup chroot badroot
  umount: bad usage
  Try 'umount --help' for more information.
---
 common | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/common b/common
index 65f3362..e9cecd8 100644
--- a/common
+++ b/common
@@ -91,7 +91,9 @@ chroot_setup() {
 }
 
 chroot_teardown() {
-  umount "${CHROOT_ACTIVE_MOUNTS[@]}"
+  if (( ${#CHROOT_ACTIVE_MOUNTS[@]} )); then
+    umount "${CHROOT_ACTIVE_MOUNTS[@]}"
+  fi
   unset CHROOT_ACTIVE_MOUNTS
 }