It could be that I don't understand your intended Configuration yaml, but the above is what I would expect. Changing the Configuration tree to
->arrayNode('barcode_options')
->prototype('scalar')->end()
->end()
allows the above to work (with as many options under barcode_options as is needed).
it seems like your Configuration doesn't allow anything in barcode_options... ex:
It could be that I don't understand your intended Configuration yaml, but the above is what I would expect. Changing the Configuration tree to ->arrayNode('barcode_options') ->prototype('scalar')->end() ->end() allows the above to work (with as many options under barcode_options as is needed).