Incorrect receiving of arguments in RPC methods (due to Ruby 2.2.1 bug)

[TeWu]

RPC methods are defined dynamically like (gen.rb:38):

define_method method_name do |*args, **kwargs|

Due to Ruby 2.2.1 bug, arguments are not received as they ware passed to method, when:

• Method is defined using define_method.
• Method parameter list contain both *args and **kwargs.
• Method is contained in class that also contain method_missing method.

All of that requirements are fulfilled for RPC methods, which can result in situations when arguments are not received as they ware passed to those methods.

Ruby 2.2.1 argument passing bug

Minimal example:

class A
  def method_missing(method, *args, **kwargs, &block)
    super
  end
end

A.instance_eval do
  define_method "m" do |*args, **kwargs|
    p args
  end
end

a1 = A.new
a2 = A.new

a1.m(1, 2.0, "trzy", a2) #=> [nil, 1, [], {}]

a1.m(1, 2.0, "trzy", a2) prints [nil, 1, [], {}], but should print [1, 2.0, "trzy", #<A:0x000000013f50d8>].
This bug is non-existent in Ruby 2.1.5 and fixed in Ruby 2.3.0dev. Hopefully the path will be backported to 2.2 when 2.3 is released.

[TeWu]

The bug only manifest itself when last argument passed to m is A's instance.
Which means that the correct output can be obtained by calling a1.m(1, 2.0, "trzy", a2, {}) instead of a1.m(1, 2.0, "trzy", a2).