class << self vs self.method with Ruby: what's better?

Question

This Ruby Style Guide tells that is better using self.method_name instead of class method_name. But Why?

class TestClass
  # bad
           


        

Answer 1

So far the question and answers only discuss these two options:

class MyClass
  def self.method_name
    ..
  end
end

class MyClass
  class << self
    def method_name
      ..
    end
  end
end

There's a third option to consider for class methods:

class MyClass
  def MyClass.method_name
    ..
  end
end

It's not popular and is more verbose, but it's the most explicit option.

It's also less confusing if you mix up self behaviour between Python and Ruby.