diff --git a/gitflow-common b/gitflow-common
index 0cc6802..bcc6dbd 100644
--- a/gitflow-common
+++ b/gitflow-common
@@ -18,7 +18,7 @@
 
 # set logic
 has() {
-	local item=$1; shift
+	typeset item=$1; shift
 	echo " $@ " | grep -q " $item "
 }
 
@@ -31,8 +31,8 @@
 endswith() { [ "$1" != "${1#$2}" ]; }
 
 # convenience functions for checking shFlags flags
-flag() { eval FLAG='$FLAGS_'$1; [ $FLAG -eq $FLAGS_TRUE ]; }
-noflag() { eval FLAG='$FLAGS_'$1; [ $FLAG -ne $FLAGS_TRUE ]; }
+flag() { typeset FLAG; eval FLAG='$FLAGS_'$1; [ $FLAG -eq $FLAGS_TRUE ]; }
+noflag() { typeset FLAG; eval FLAG='$FLAGS_'$1; [ $FLAG -ne $FLAGS_TRUE ]; }
 
 #
 # Git specific common functionality
@@ -55,7 +55,7 @@
 
 gitflow_require_clean_working_tree() {
 	gitflow_test_clean_working_tree
-	result=$?
+	typeset -i result=$?
 	if [ $result -eq 1 ]; then
 		die "fatal: Working tree contains unstaged changes. Aborting."
 	fi
@@ -100,10 +100,10 @@
 # 3    Branch needs a real merge
 #
 gitflow_test_branches_equal() {
-	commit1=$(git rev-parse "$1")
-	commit2=$(git rev-parse "$2")
+	typeset commit1=$(git rev-parse "$1")
+	typeset commit2=$(git rev-parse "$2")
 	if [ "$commit1" != "$commit2" ]; then
-		base=$(git merge-base "$commit1" "$commit2")
+		typeset base=$(git merge-base "$commit1" "$commit2")
 		if [ "$commit1" = "$base" ]; then
 			return 1
 		elif [ "$commit2" = "$base" ]; then
@@ -120,7 +120,7 @@
 	gitflow_require_local_branch "$1"
 	gitflow_require_remote_branch "$2"
 	gitflow_test_branches_equal "$1" "$2"
-	status=$?
+	typeset -i status=$?
 	if [ $status -gt 0 ]; then
 		warn "Branches '$1' and '$2' have diverged."
 		if [ $status -eq 1 ]; then
@@ -140,9 +140,8 @@
 # Checks whether branch $1 is succesfully merged into $2
 #
 gitflow_is_branch_merged_into() {
-	local SUBJECT=$1
-	local BASE=$2
-	ALL_MERGES=$(git branch --contains $SUBJECT | sed 's/^[* ] //')
-	has $BASE $ALL_MERGES
+	typeset subject=$1
+	typeset base=$2
+	typeset all_merges=$(git branch --contains $subject | sed 's/^[* ] //')
+	has $base $all_merges
 }
-