[Python-bugs-list] [ python-Bugs-762891 ] "del p[key]" on proxy object raises SystemError()

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Bugs item #762891, was opened at 2003-06-29 17:17
Message generated for change (Settings changed) made by rhettinger
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Category: Python Interpreter Core
Group: Python 2.2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Michael Muller (mikemuller)
>Assigned to: Raymond Hettinger (rhettinger)
Summary: "del p[key]" on proxy object raises SystemError()

Initial Comment:
Attempting to perform a __delitem__ on a proxy object
raises the SystemError "null argument to internal
routine".  Example code:

-------------------------------------------------------
import weakref

class Foo:
   def __delitem__(self, accessor):
      print 'deleting %s' % accessor

g = Foo()
f = weakref.proxy(g)
del f[0]

-------------------------------------------------------

The problem appears to be that proxy_setitem() in
weakrefobject.c indiscriminately calls
PyObject_SetItem() on the proxied object without
checking to see if the "value" parameter is NULL, as it
is when it is called from a __delitem__ on the proxy.

I have uploaded a patch that fixes the problem.


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