From: Han Holl <han.holl@...>
Date: 2004-07-09T22:46:22+09:00
Subject: Freezing objects without Kernel#freeze


Hello,

Having some trouble with REXML, but this post is not (primarily)
about that.
REXML-2.7.1 informs me that it cannot modify a frozen object.
The culprit is an attribute with a value of "lym<II", and rexml
does a copy = input.clone and copy.gsub!() to do entity replacement.
My problem: who froze that string.
To detect that, I put the following at the start of the program:

$GGG = File.open('/tmp/freeze', 'a')
module Kernel
alias o_freeze freeze
  def freeze
    $GGG.puts "Freeze #{self.class}:#{self.object_id} #{self}\n"
    $GGG.puts caller(0)
    $GGG.flush
    o_freeze
  end
end
and in rexml/text.rb a begin..rescue TypeError ... end to print the
object_id of the frozen string.
It never showed up in /tmp/freeze.
My question: how can REXML, which is pure ruby, freeze something
without it showing up in the file produced by the above trap?
Is there another way of freezing that bypasses Kernel#freeze ?

Cheers,

Han Holl

PS REXML-3.1.1 doesn't produce this error message, so it's not urgent,
but I am curious.