From: Eric Hodel <drbrain@...7.net>
Date: 2007-12-21T16:40:06+09:00
Subject: Re: First stab at a weakref test suite

On Dec 20, 2007, at 21:45 PM, Daniel Berger wrote:
> Hi all,
>
> I decided to take a stab at creating a minimal test suite for  
> WeakRef (based on a post by Charles Oliver Nutter for JRuby). The  
> only problem is that I get two unexpected failures. I'm not sure if  
> it's Test::Unit fighting with me or what.
>
> Consider the following example:
>
> require 'weakref'
> str = 'hello'
> ref = WeakRef.new(str)
>
> p ref 'hello'
> GC.start
> p ref 'hello'
> str = nil
> p ref # 'hello'
> GC.start
> p ref # error
>
> I follow the same pattern in the tests, but it doesn't raise the  
> expected error. Any ideas?

Since the GC is conservative, references may exist longer than you  
expect because the item that should be collected is still referenced  
from the stack.  I don't know of an easy way around this.