Issue #8543 has been reported by alvoskov (Alexey Voskov).

----------------------------------------
misc #8543: rb_iseq_load
https://bugs.ruby-lang.org/issues/8543

Author: alvoskov (Alexey Voskov)
Status: Open
Priority: Normal
Assignee: ko1 (Koichi Sasada)
Category: YARV
Target version: current: 2.1.0


I noticed an unusual behaviour of undocumented rb_iseq_load function. 
Its work differs in different Ruby versions. I'm trying to protect some Ruby
source code by its conversion to YARV p-code and using the next strategy:
1) Convert code to array
data = RubyVM::InstructionSequence.compile_file('hello.rb').to_a

2) Pass a compiled source to the rb_iseq_load function and evaluate it
iseq = iseq_load.(data)
iseq.eval

Sample programs are supplied in the attachments.
"hello.rb"
---------------------------
puts "tralivali"
def funct(a,b)
	a**b
end

3.times { |i|
	puts "Hello, world#{funct(2,i)}!"
}
------------------------


The differences
Ruby 1.9.3 (ruby 1.9.3p194 (2012-04-20) [i386-mingw32])
Correct work. Output:
-------------------------
tralivali
Hello, world1!
Hello, world2!
Hello, world4!

--------------------

Ruby 2.0.0 (ruby 2.0.0p193 (2013-05-14) [x64-mingw32])
Incorrect work (omits the code inside code blocks). Output
-------------------------
tralivali

-------------------------

Attempts of loading bigger programs by means of rb_iseq_load in Ruby 2.0.0 usually ends with a segmentation fault.

Such behaviour also can be reproduced by means of iseq Ruby extension ("for iseq freaks")
https://github.com/wanabe/iseq

P.S. I understand that it is an undocumented feature.


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