Question

There is a Gem in my dependency list that is Monkey Patching to_json on String.

How can I figure where this monkey patching is happening?

Answer 1

Use source_location.

Returns the Ruby source filename and line number containing this method or nil if this method was not defined in Ruby (i.e. native)

$ cat monkey.rb
class String
  def reverse
    ""
  end
end

p String.instance_method(:reverse).source_location
$ ruby monkey.rb
["monkey.rb", 2]