From: Ryan Davis <ryand-ruby@...>
Date: 2009-09-18T15:40:16+09:00
Subject: Re: Kernel.eval("local_variables",binding) bug in Ruby 1.9

Please send this to ruby-core@

On Sep 17, 2009, at 16:30 , Howard Yeh wrote:

> Hi,
>
> My ruby runtime is "ruby 1.9.1p0 (2009-01-30 revision 21907) [i686-
> linux]"
>
> Kernel eval works for these cases:
>
> puts "2 times"
> 1.times do
>  a = 1
>  p Kernel.eval("local_variables",binding)
> end
>
> puts "while"
> while true
>  a = 1
>  p Kernel.eval("local_variables",binding)
>  break
> end
>
> puts "lambda"
> lambda {
>  a=1
>  p Kernel.eval("local_variables",binding)
> }.call
>
>
> But I get a segfault with
>
> for i in 1..100
>  a = 1
>  p Kernel.eval("local_variables",binding)
>  break
> end
>
> But you can try,
>
> for i in 1..100
>  a = 1
>  r = Kernel.eval("local_variables",binding)
>  p r.length # => 4, but should be 3
>  p r[1..-1] # => [:i,:a,:r]
>  p r.first.class # => Symbol
>  p r.first.object_id # => 4087
>  p r.first  # segfault
>  break
> end
>
> And we see that there's an extraneous variable reported by evaluating
> local_variables. The first element of the result seems an invalid
> pointer?
>
> for i in 1..100
> p Kernel.eval("local_variables") # this works
> break
> end
>
>