- if champ.options?
  = form.select :primary_value,
    champ.primary_options,
    { required: champ.mandatory? },
    { data: { secondary_options: champ.secondary_options } }
  %span
    = form.label :secondary_value, "Valeur secondaire dépendant de la première", class: 'hidden'
  = form.select :secondary_value,
    champ.secondary_options[champ.primary_value],
    { required: champ.mandatory? },
    { data: { secondary: true } }

- if champ.options?
  = form.select :primary_value,
    champ.primary_options,
    { required: champ.mandatory? },
    { data: { secondary_options: champ.secondary_options } }
  %span
    = form.label :secondary_value, class: 'hidden' do
      Valeur secondaire dépendant de la première
      - if champ.mandatory?
        %span.mandatory *
  = form.select :secondary_value,
    champ.secondary_options[champ.primary_value],
    { required: champ.mandatory? },
    { data: { secondary: true } }

Add mandatory * to secondary value
Add mandatory * to secondary value
