如何使用类<< self eigenclass模式从ruby中的类动态删除remove_method？

Question

I'm trying to dynamically undefine a method by opening up the eigenclass of the class. I want something like:

def remove_defined_mock_name_method(name)
  if Settings.respond_to?(name)
    class << Settings
      remove_method name
    end
  end
end

where 'name' is a symbol. Problem is name is not available to the reopened class. How can I achieve undefining a class method dynamically like this through a method call?

For those curious, the use case is that I want to undefine a dynamically defined method after each test in rspec for rails.

Answer 1

name is a local variable. Local variables are local to the scope they are defined in, that's why they are called local variables. The only construct in Ruby that creates a nested scope is a block, so you would have to use a block if you want to have access to name , ie by using class_eval or something like that.

But in this case, that's not necessary:

def remove_defined_mock_name_method(name)
  Settings.singleton_class.send(:remove_method, name) if Settings.respond_to?(name)
end