WeakValueDictionary constructor ported to Python 3.0 incorrectly #50399

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1. zzzeek commented on May 30, 2009

   

   zzzeekmannequin

   on May 30, 2009

   MannequinAuthor

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   The constructor for WeakValueDictionary does not obey the contract
   documented in its comments:

   # We inherit the constructor without worrying about the input
   # dictionary; since it uses our .update() method, we get the right
   # checks 
   

   yet it initializes with:

      self.data = d = {}
      d.update(*args, **kw)

   i.e. the "update()" method of dict, so that a dict passed to the
   constructor initializes non-weakrefed values in the dict which is
   completely invalid state.

   Contrast to that of 2.6, which properly uses the superclass:

   UserDict.UserDict.__init__(self, *args, **kw)

   A simple test which raises an exception on 3.0.1 is as follows:

   import weakref
   
   class Foo(object):
       pass
       
   mydict = dict((k, Foo()) for k in range(10))
   
   w = weakref.WeakValueDictionary(mydict)

   assert w[5]
2. zzzeek

   added

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   type-crashA hard crash of the interpreter, possibly with a core dumpA hard crash of the interpreter, possibly with a core dump

   on May 30, 2009
3. pitrou commented on May 30, 2009

   

   pitrou

   on May 30, 2009

   Member

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   Here is a patch for 3.1.
4. pitrou commented on May 30, 2009

   

   pitrou

   on May 30, 2009

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   Fixed in r73063. Thanks!
5. pitrou

   closed this as completedon May 30, 2009
6. ezio-melotti

   transferred this issue fromon Apr 10, 2022