Question

Let’s say your coworker monkeypatches the Fixnum class and redefines the + method to subtract instead of add:

class Fixnum
  def +(x)
    self - x
  end
end

>> 5 + 3
=> 2

Your problem is you want to access the original functionality of the + method. So you drop this code in before his in the same source file. It aliases the + method to “original_plus” before he monkeypatches it.

class Fixnum
  alias_method :original_plus, :+
end

class Fixnum
  def +(x)
    self - x
  end
end

Now you can access the original functionality of the + method through original_plus

>> 5 + 3
=> 2
>> 5.original_plus(3)
=> 8

But what I need to know is this:

Is there any other way of loading this alias BEFORE his monkeypatch loads besides sticking it into the same source file that he modified?

There are two reasons for my question:

1. I may not want him to know that I have done this
2. If the source file is altered so that the alias ends up BELOW the monkeypatch, then the alias will no longer produce the desired result.

Answer 1

Sure. Just stick the anti-monkeypatch in your code before you require his source file.

 % cat monkeypatch.rb
 class Fixnum
   def +(x)
     self - x
   end
 end
 % cat mycode.rb
 class Fixnum
   alias_method :original_plus, :+
 end
 require 'monkeypatch'
 puts 5 + 3 #=> 2
 puts 5.original_plus(3) #=> 8