From: "ara.t.howard" <ara.t.howard@...>
Date: 2007-09-26T01:01:57+09:00
Subject: ObjectSpace.define_finalizer and memory leaks


i don't think i've ever noticed this behaviour:

cfp:~ > cat a.rb

class C
   def self.count
     c = 0
     ObjectSpace.each_object do |object|
       c += 1 if self === object rescue next
     end
     c
   end
end

loop do
   c = nil  ### try with and without this!!!!!!!!!!!!!!

   (2 ** 16).times do
     c = C.new
     object_id = c.object_id
     ObjectSpace.define_finalizer(c){ :nothing }
   end

   puts "before: #{ C.count }"

   GC.start

   puts "after: #{ C.count }"
   puts
end



run both ways.  notice that, without the prior declaration of c, the  
code leaks like crazy: the finalizer itself holds a reference to the  
object and prevents it being reaped.  i don't think i've ever noticed  
this behavior before.  i understand it - but can this be correct?  it  
seems like you should be able to define a finalizer on any object  
without preventing it from being gc'd!

cheers.

a @ http://drawohara.com/
--
we can deny everything, except that we have the possibility of being  
better. simply reflect on that.
h.h. the 14th dalai lama