[issue24590] Customized attribute access causes infinite loop
Zorceta
report at bugs.python.org
Wed Jul 8 11:07:22 CEST 2015
New submission from Zorceta:
Code and result:
```
>>> class A:
def __init__(self):
self.data = {'a': 1, 'b': 2, 'c': 3}
def __getattr__(self, name):
print('in __getattr__, getting %s' % name)
if name in self.data:
return self.data[name]
else:
raise AttributeError
def __setattr__(self, name, value):
print('in __setattr__, setting %s to %s' % (name, value))
if name in self.data:
self.data[name] = value
else:
self.__class__.__setattr__(self, name, value)
>>> a = A()
in __setattr__, setting data to {'a': 1, 'b': 2, 'c': 3}
in __getattr__, getting data
in __getattr__, getting data
in __getattr__, getting data
......
```
>From above you can see it stuck on
>>> if name in self.data:
in `__setattr__`.
But, the result indicates that `__setattr__` uses `__getattr__` to read the `data` attribute, which is against docs:
"Note that if the attribute is found through the normal mechanism, __getattr__() is not called."
If it acts as described, `data` should be read "through the normal mechanism", not through `__getattr__`.
----------
messages: 246453
nosy: zorceta
priority: normal
severity: normal
status: open
title: Customized attribute access causes infinite loop
type: behavior
versions: Python 3.4
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<http://bugs.python.org/issue24590>
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