[Python-Dev] PEP 442: Safe object finalization (original) (raw)

Richard Oudkerk shibturn at gmail.com
Sat May 18 16:52:56 CEST 2013

On 18/05/2013 3:18pm, Antoine Pitrou wrote:

It works fine:

$ ./python sbt.py <_main_.Node object at 0x7f3acbf8f400> <_main_.Node object at 0x7f3acbf8f878> <_main_.Node object at 0x7f3acbf8f878> <_main_.Node object at 0x7f3acbf8f400> The reason is that, when you execute "del self.next", this removes the last reference to self.next and destroys it immediately.

So even more contrived:

  class Node:
      def __init__(self, x):
          self.x = x
          self.next = None
      def __del__(self):
          print(self.x, self.next.x)
          del self.x

  a = Node(1)
  b = Node(2)
  a.next = b
  b.next = a
  del a, b
  gc.collect()

-- Richard

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