## cart

class Cart
  has_many :products
  accepts_nested_attributes_for :products
end

## controller

class CartController < ApplicationController
  def update
    delete_zero_quantity_params
    @cart.update_attributes params[:cart]
    @cart.save
    debugger  # see below
  end

  private

  def delete_zero_quantity_params
    if params['cart']['products_attributes']
      params['cart']['products_attributes'].map do |i, product|
        product['_delete'] = true if product[:quantity].to_i == 0
      end
    end
  end
end

## debugger

params
# {"cart"=>{"products_attributes"=>{"0"=>{"_delete"=>true, "quantity"=>"0", "id"=>"1"}}}, "action"=>"update", "controller"=>"cart"}
@cart.products
# [#<Product id: 1, design_id: 1, order_id: 1, quantity: 1, amount: #<BigDecimal:33402e4,'0.995E1',8(20)>, state: "cart", created_at: "2009-05-23 16:37:31", updated_at: "2009-05-23 16:42:44">]

@cart.products[0].attributes = params[:cart][:products_attributes]['0']
# {"_delete"=>true, "quantity"=>"0", "id"=>"1"}
@cart.products[0].marked_for_destruction?
# nil

## Question [plain_text]

In the debugger, quantity:1 is expected because I normalize it for a
"minimum order" in the product model. Regardless, the whole thing
should have just been deleted.

Any ideas why the product wasn't deleted from the cart?