2010/1/6 Martin Aspeli <optilude+li...@gmail.com>:
> Hi,
>
> This one is pretty high no the list of weirdest things to have happened
> to me in a while. Basically, I have a persistent object that has an
> empty __dict__() on the first request, until it suddenly decides to have
> data again.
>
> I'm on ZODB 3.9.3, using Zope 2.12 and Plone 4. I have a persistent
> object, /plone/portal_registry:
>
> class Registry(registry.Registry, SimpleItem):
> pass
>
> The base class is:
>
> class Registry(Persistent):
> def __init__(self):
> self._records = Records(self)
>
> Records is:
>
> class Records(Persistent):
>
> __parent__ = None
>
> def __init__(self, parent):
> self.__parent__ = parent
> self.data = OOBTree()
>
> def __getitem__(self, name):
> return self.data.__getitem__(name)
>
> The BTree contains string keys and Record objects as values. Record is:
>
> class Record(Persistent):
> __name__ = u""
> __parent__ = None
>
> field = None
>
> __parent__ is set to records.__parent__, which is going to be the
> Registry object.
>
> field is set to a special persistent field class inheriting from
> zope.schema's fields, but mixing in persistence. In this case, I have a
> list field:
>
> class PersistentField(persistent.Persistent):
> """Base class for persistent field definitions.
> """
>
> class PersistentCollectionField(PersistentField,
> zope.schema._field.AbstractCollection):
>
> class List(PersistentCollectionField, zope.schema.List):
> pass
>
> I then have some code like this:
>
> def cloneField(self, field):
> clone = field.__class__.__new__(field.__class__)
> clone.__dict__.update(field.__dict__)
> for name, attr in field.__dict__.items():
> if IField.providedBy(attr):
> clone.__dict__[name] = self.cloneField(attr)
> return clone
>
> This is used like so:
>
> registry = getUtility(IRegistry) # persistent/local
> clone = self.cloneField(registry.records[recordName].field)
>
> This seems to work always *except* on the first request immediately
> after starting up Zope. In this case, field.__dict__ is {}. If I poke at
> it long enough in pdb, it suddenly springs into life and contains values
> again.
>
> Can anyone enlighten me as to:
>
> - why this may happen
> - how I can ensure it stops happening :-)
I don't know if this should ever happen when you access
persistentobj.__dict__, but it sounds as if it is in the ghost state.
What is clone._p_state at this point (-1 would be a ghost object, 0 =
normal object, 1 = modified object).
You could do clone._p_activate() first.
Laurence
_______________________________________________
For more information about ZODB, see the ZODB Wiki:
http://www.zope.org/Wikis/ZODB/
ZODB-Dev mailing list - ZODB-Dev@zope.org
https://mail.zope.org/mailman/listinfo/zodb-dev
