[Zope-dev] ZODB now supports user-defined __get/set/delattr__ methods

[Phillip J. Eby]

FYI, I have found a problem with the setattr/delattr implementation.  I'm
not sure it's technically a bug, but if I understand the code correctly,
setting or deleting a non _v_ attribute on a cPersistent will always cause
the object to be marked changed, regardless of what the Python-level
__set/delattr__ routine does.  This seems incorrect for situations where
the Python-level code is manipulating an external attribute.  IMHO, the
correct behavior would be to require a "persistent" __setattr__ or
__delattr__ to use _p_changed directly if they are manipulating the object
data.  This is the algorithm used by ZPatterns, and also seems consistent
with the normal semantics of having a __setattr__ or __delattr__ routine -
i.e., if you implement a set/del hook, you have to implement it completely.

At 02:02 PM 5/16/00 -0400, Jim Fulton wrote:
>
>I've just checked in some changes to ExtensionClass, 
>and ZODB in the Zope CVS tree that provide support 
>for user-defined (python) __get/set/delattr__ methods.  
>These methods now have the same semantics as they do 
>in standard Python classes.  
>
>This means that you can define your own 
>__get/set/delattr__ hooks and they will automatically
>work with, rather than break, the persistence system's
>use of the low-level attribute hooks.