[Zope-CMF] Re: five.intid and DirectoryView

[Ross Patterson]

Tres Seaver <tseaver at palladion.com> writes:

> Martijn Pieters wrote:
>> On Fri, Jun 27, 2008 at 6:53 PM, Ross Patterson <me at rpatterson.net> wrote:
>>> "Martijn Pieters" <mj at zopatista.com> writes:
>>>> But the code never does that. When cloning a file-based FSObject, a
>>>> new instance is created and that is added to the ZODB. Noone else
>>>> should do this either.
>>> zope.app.keyreference does.  The persistence machinery doesn't add an
>>> object to a connection until commit.  As such, an IPersistent and
>>> IObjectAdded event handler, such as the one in zope.app.intid, that
>>> needs the object to have a connection needs to add the object to a
>>> connection.
>
> Sounds like a bug in zope.app.intid to me:  it shouldn't be forcing
> objects to have connections.
>
>> Why is the IObjectAdded event fired at all? Perhaps that's the bug here.
>> 
>>> Shouldn't anything that implements IPersistent be able to be added to a
>>> connection?  Wouldn't that be considered part of providing the
>>> interface?  Where else is an object that provides IPersistent stored in
>>> global state?
>> 
>> I assume it was easier at the time to use just one class. Perhaps this
>> should be reconsidered now. However, just providing the IPersistence
>> interface does not mean the object expects to be added to a connection
>> arbitrarily.
>
> Exactly.  Nobody is supposed to add objects to a connection except their
> already-persisted containers.

That sounds right to me especially given that an object's parent isn't
necessarily "where" the object is persisted.  Shouldn't it be possible,
for example, to have a container that looks up it's contained items from
a utility that actually is stored in another ZODB.  Such a container's
items would not share their parent's connection.

FWIW, this happens in zope.app.keyreference.  The reason it needs the
object to have a connection is so that it can get the object's _p_oid.
If this is a bug, how can zope.app.keyreference get _p_oid for an object
added in the current, as yet uncommitted transaction?

Ross