module ActiveSupport::Callbacks::ClassMethods

def skip_callback(name, *filter_list, &block)

already been set (unless the :raise option is set to false).
An ArgumentError will be raised if the callback has not

saved
- save
saving...
Output:

young_writer.save
young_writer.age = 17
young_writer = Writer.new

When if option returns false, callback is NOT skipped.

saved
- save
Output:

writer.save
writer.age = 20
writer = Writer.new

When if option returns true, callback is skipped.

end
skip_callback :save, :before, :saving_message, if: -> { age > 18 }
attr_accessor :age
class Writer < PersonRecord

can see defined here[rdoc-ref:ActiveSupport::Callbacks]
Note: this example uses +PersonRecord+ and +#saving_message+, which you

callback is skipped.
:unless options may be passed in order to control when the
Skip a previously set callback. Like #set_callback, :if or 
def skip_callback(name, *filter_list, &block)
  type, filters, options = normalize_callback_params(filter_list, block)
  options[:raise] = true unless options.key?(:raise)
  __update_callbacks(name) do |target, chain|
    filters.each do |filter|
      callback = chain.find { |c| c.matches?(type, filter) }
      if !callback && options[:raise]
        raise ArgumentError, "#{type.to_s.capitalize} #{name} callback #{filter.inspect} has not been defined"
      end
      if callback && (options.key?(:if) || options.key?(:unless))
        new_callback = callback.merge_conditional_options(chain, if_option: options[:if], unless_option: options[:unless])
        chain.insert(chain.index(callback), new_callback)
      end
      chain.delete(callback)
    end
    target.set_callbacks name, chain
  end
end