如果父级尚未更改，则Rails has_many不会在保存时更新

Question

模型之间有以下关系：

class Gift 
    has_and_belongs_to_many :constituents, :autosave => true
    accepts_nested_attributes_for :constituents
end


class Constituent
    has_and_belongs_to_many :gifts
    has_many :addresses, :autosave => true
end

class Address 
    belongs_to :constituent
end

只有在@gift.save记录中检测到更改时，我的控制器address才会更新相应的constituent记录。

但如果address记录发生变化但constituent记录中没有变化，则address记录不会更新。

在我的控制器中，我只是运行save!方法：

def create
    @gift = Gift.new
    @gift.assign_attributes gift_params
    p @gift.constituents[0].addresses[0].changed? #Prints true
    @gift.save!
end

def gift_params
    params.require(:gift).permit(:amount, :constituents_attributes => [:id, :organization_name, :title_id, :first_name, :last_name, :addresses_attributes => [ :id, :address_type, :address1, :address2, :city, :country_id, :state_id, :pin_code, :constituent_id ]])
end

参数的一个例子是：

{"utf8"=>"✓", "gift"=>
    {"constituents_attributes"=>{"0"=>{"id"=>"5", "title_id"=>"", "first_name"=>"Mridula", "last_name"=>"Prabhu", 
        "addresses_attributes"=>{"0"=>{"id"=>"16", "constituent_id"=>"5", "address_type"=>"home", "address1"=>"Line1", "address2"=>"Line2", "city"=>"Pune", "country_id"=>"38", "state_id"=>"53", "pin_code"=>"M2M 2M2"
        }
    }, 
    "amount"=>"20" 
}

我该如何解决这个问题？