module Spree
  module Stock
    Quantifier.class_eval do
      durably_decorate :can_supply?, mode: 'soft', sha: '2759d397d8dafe5bc3e5eed2d881fa0ab3a1a7c9' do |required|
        original_can_supply?(required) || Spree::Variant.find(@variant).product.is_gift_card?
      end
    end
  end
end

module Spree
  module Stock
    Quantifier.class_eval do
      durably_decorate :can_supply?, mode: 'soft', sha: '2759d397d8dafe5bc3e5eed2d881fa0ab3a1a7c9' do |required|
        original_can_supply?(required) || Spree::Variant.find(@variant.id).product.is_gift_card?
      end
    end
  end
end

Update .find to work with rails 4.2
Update .find to work with rails 4.2
