fix(xfunc ARRAY filter): work around nounset

Author: akinomyoga

bash_completion

@@ -901,7 +901,7 @@ _comp_finalize()
 {
     ((${#_comp_finalize__depth[@]})) || return 0
     while ((${#FUNCNAME[@]} <= ${_comp_finalize__depth[-1]})); do
-        if [[ ${#FUNCNAME[@]} -eq ${_comp_finalize__depth[-1]} && ${FUNCNAME[1]} == "${_comp_finalize__target[-1]}" ]]; then
+        if [[ ${#FUNCNAME[@]} -eq ${_comp_finalize__depth[-1]} && ${FUNCNAME[1]-} == "${_comp_finalize__target[-1]}" ]]; then
             # Call finalizer for each command
             local cmd=${words[0]-} _comp_local_hook
             if [[ $cmd ]]; then
@@ -970,7 +970,7 @@ _init_completion()
             trap _comp_finalize RETURN
         fi
         _comp_finalize__depth+=("${#FUNCNAME[@]}")
-        _comp_finalize__target+=("${FUNCNAME[1]}")
+        _comp_finalize__target+=("${FUNCNAME[1]-}")
     fi
 
     while getopts "n:e:o:i:s" flag "$@"; do