From: wvdbos@...
Date: 2005-04-08T22:13:54+09:00
Subject: Re: ruby 1.8.3 preview1 plan

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Did you look at the GC problem I wrote about some time ago?

In case the message is gone here it i again:



I tried the following script:


#====================
class Example
end

a=Example.new
ObjectSpace.each_object(Example) { |e| print e,"\n" }
a=nil
GC.enable
GC.start
ObjectSpace.each_object(Example) { |e| print e,"\n" }
#====================
Output:
#<Example:0x2a66e68>
#<Example:0x2a66e68>

The Example object is still active after the GC.start, I expected it to be 
gone. :-(

So I tried the WeakRef, and this also did something strange.

I wrote the 'Programming Ruby' book example:

#====================
require "weakref"

ref = "fol de rol"
puts "Initial object is #{ref}"
ref = WeakRef.new(ref)
puts "Weak reference is #{ref}"
ObjectSpace.garbage_collect
begin
  puts "But then it is #{ref}"
rescue Exception=>e
  puts e
end
#====================
Output:
Initial object is fol de rol
Weak reference is fol de rol
Illegal Reference - probably recycled

And this worked ok. 
I then copied the whole and just defined a class in between:

#====================
require "weakref"

ref = "fol de rol"
puts "Initial object is #{ref}"
ref = WeakRef.new(ref)
puts "Weak reference is #{ref}"
ObjectSpace.garbage_collect
begin
  puts "But then it is #{ref}"
rescue Exception=>e
  puts e
end
#
# doing it for the second time, and created a class definition
# and now it doesn't work
#
class Example
end
#
ref = "fol de rol"
puts "Initial object is #{ref}"
ref = WeakRef.new(ref)
puts "Weak reference is #{ref}"
ObjectSpace.garbage_collect
begin
  puts "But then it is #{ref}"
rescue Exception=>e
  puts e
end
#====================
Output:

Initial object is fol de rol
Weak reference is fol de rol
Illegal Reference - probably recycled
Initial object is fol de rol
Weak reference is fol de rol
But then it is fol de rol

And this is strange the second 'ref' is not collected. If the class 
definition is removed all works well.

I tested this in the mswin32 version. 1.8.2 and in the older version 1.6.8 
both with the same results.
The cygwin version 1.8.2 had the same results also.

To be sure I the downloaded 1.9.0 and this also went wrong.

It looks like the Garbage Collector is not working properly. Can anybody 
help.

Thanks.
Wim...






Yukihiro Matsumoto <matz@ruby-lang.org> 
07-04-2005 07:03
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Subject
ruby 1.8.3 preview1 plan






Hi,

I am going to release 1.8.3 preview1 on April 12, unless something
would stop me.  Core contributors who want to update their libraries
for 1.8.3, please consider updating your code before preview1.
And someone who found bugs for 1.8 CVS, please report here.

                                 matz.


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