Python object initialization bug. Or am I misunderstanding how objects work?

Question

  1 import sys
  2 
  3 class dummy(object):
  4     def __init__(self, val):
  5         self.val = val
  6 
  7 class myobj(object):
  8     def __init__(self, resourc         


        

Answer 1

Please read this answer for a discussion of how to setup a class from __init__(). You have encountered a well-known quirk of Python: you are trying to set up a mutable, and your mutable is being evaluated once when __init__() is compiled. The standard workaround is:

class ext(myobj):
    def __init__(self, resources=None):
        if resources is None:
            resources = []
        #myobj.__init__(self, resources)
        self._resources = resources