How to interpolate instance variables in deface and Spree?

Question

I'm trying to add a max value to this form in a partial for Spree using Deface.

Deface::Override.new(
  :virtual_path => 'spree/products/_cart_form',
  :name => 'modify_max_add_to_cart',
  :replace_contents => ".add-to-cart",
  :text => "
          <%= number_field_tag (@product.variants_and_option_values.any? ? :quantity : 'variants[#{@product.master.id}]\'),
            1, :class => 'title', :min => 1, :max => @product.limit_qty %>
          <%= button_tag :class => 'large primary', :id => 'add-to-cart-button', :type => :submit do %>
            <%= Spree.t(:add_to_cart) %>
          <% end %>
  ")

The issue is, it seems to bug out because there's instance variables there.

undefined method master for nil:NilClass

How do I do this properly?

Answer 1

When you changed this line

<%= number_field_tag (@product.variants_and_option_values.any? ? :quantity : "variants[#{@product.master.id}]")

to use single quotes, you broke the variable interpolation that was occuring in this bit of code:

"variants[#{@product.master.id}]"

You can fix this by changing the line to:

<%= number_field_tag (@product.variants_and_option_values.any? ? :quantity : \"variants[#{@product.master.id}]\")

In fact, rather than using the text replacement, you should consider using the partial replacement. It's quite a bit clearer with multiple lines of code.