[PATCH 4/9] dim: use ${1:?$usage} for create-workdir argument checking

[Jani Nikula]

The benefit of ${1:?$usage} is two-fold. First, it allows enabling of
set -u without errors about unbound variable references. Second, it
provides a uniform error message about missing arguments.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 dim | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/dim b/dim
index 2496703aac7f..b41beca7301b 100755
--- a/dim
+++ b/dim
@@ -1602,19 +1602,16 @@ function prep_pull_mail
 
 function dim_create_workdir
 {
-	local branches
+	local branch branches
 
-	cd $DIM_PREFIX
+	branches=${1:?$usage}
 
-	if [[ "x$1" = "x" ]]; then
-		echo "usage: $dim $subcommand branch|all"
-		exit 1
-	elif [[ "$1" = "all" ]] ; then
+	if [[ "$branches" = "all" ]]; then
 		branches=$dim_branches
-	else
-		branches=$1
 	fi
 
+	cd $DIM_PREFIX
+
 	for branch in $branches ; do
 		if [[ -d $branch ]] ; then
 			continue;
-- 
2.11.0