Why does Ruby have two methods send and __send__?

Question:

Ruby objects have a method called send that we can call methods dynamically.

class MyClass
  private
  def true_method?
    true
  end
end

Example:

mc = MyClass.new
mc.send(:true_method?)
mc.__send__(:true_method?)

Why do you have these two methods?

Answer:

Since dynamic modifications such as method overrides are a common sight in Ruby,Object#__send__ and Object#send is a way to protect objects from being overwritten. __send__ serves as an internal alias, which you can use if your object has any send redefinitions. For example:

"hello world".send :upcase
=> "HELLO WORLD"

module EvilSend
  def send(foo)
    "Não foi dessa vez..."
  end
end

String.include EvilSend
"hello world".send :upcase
=> "Não foi dessa vez"

"hello world".__send__ :upcase
=> "HELLO WORLD"

Note that there is no warning from Ruby about overriding this method. That's why there is __send__ . The method that CANNOT be overridden under any circumstances is __send__ . If you try, Ruby throws a warning .

warning: redefining ' __send__ ' may cause serious problems