bash：数组变量替换错误

Question

Below is my extract of the failure part:

if [[ -n "${war_to_be_deployed-}" ]] ; then
    [[ "${#runtime_args[@]-}" == "${#expected_runtime_args[@]-}" ]]             || _fatal "Failed runtime_args"     
    for ((i=0 ; i<${#runtime_args[@]-} ; ++i)); do

throws below error on bash GNU bash, version 4.4.20(1)-release (x86_64-pc-linux-gnu) . What is it that I'm doing incorrect here? thank you.

${#runtime_args[@]-}: bad substitution

Answer 1

${#runtime_args[@]} is number of elements in the array. The trialing - is what triggers the error. Is this script generated? It looks like a syntax error to me.