Weird UserArray AttributeError (bug ?)

[George Sakkis]

I came across a strange error when trying to define a settable property
for a new-style subclass of UserArray (Numeric). Here's a shorter
example that reproduces the problem:


from UserArray import UserArray
from math import hypot

class Vector(UserArray,object):
    def __init__(self,x,y):
        super(Vector,self).__init__((x,y))

    def _fget(self): return hypot(*self)
    def _fset(self, m): self *= m/self.magnitude
    magnitude = property(_fget, _fset)


v = Vector(3.,4.)
print v.magnitude
# the line below prints an infinite sequence of:
# Exception exceptions.AttributeError: "can't delete attribute"
# in  ignored
v.magnitude = 10


Any ideas on what's going on and if there's a workaround ?

George