spree-contrib/spree_drop_ship

module Dropship
  module Spree
    module VariantDecorator
      def self.prepended(base)
        base.has_many :supplier_variants
        base.has_many :suppliers, through: :supplier_variants

        base.before_create :populate_for_suppliers
      end

      private

      def create_stock_items
        ::Spree::StockLocation.all.find_each do |stock_location|
          if stock_location.supplier_id.blank? || suppliers.pluck(:id).include?(stock_location.supplier_id)
            stock_location.propagate_variant(self) if stock_location.propagate_all_variants?
          end
        end
      end

      def populate_for_suppliers
        self.suppliers = product.suppliers
      end
    end
  end
end

Spree::Variant.prepend Dropship::Spree::VariantDecorator