ZODB cross-database savepoints forget explicit connection adds

[Fred Drake]

It's possible for an object's association with a connection during the course of a transaction can be forgotten during a savepoint.

Here's one way to trigger this (may be oversimplified):

1. Add an object to a specific connection.

2. Call transaction.savepoint().

3. Add a reference to the object from an object associated with another connection.

4. Call transaction.savepoint().

An exception gets generated at this point:

InvalidObjectReference: A new object is reachable from multiple databases. Won't try to guess which one was correct!

(Raised by ZODB.serialize.ObjectWriter.persistent_id() after checking obj._p_jar._implicitlyAdded().)

[Jim Fulton (jim-zope)]

On Jul 23, 2008, at 1:16 PM, Fred Drake wrote:

> Public bug reported:
>
> It's possible for an object's association with a connection during the
> course of a transaction can be forgotten during a savepoint.

The problem is that Connection._implicitlyAdding considers something
to be implicitly added if it was added in a savepoint -- even if it
was explicitly added to the savepoint.

Jim

--
Jim Fulton
Zope Corporation

[Jim Fulton (jim-zope)]

I can't reproduce this. I tried:

>>> db = ZODB.DB(None)
>>> db2 = ZODB.DB(None, database_name='2', databases=db.databases)
>>> c = db.open()
>>> o = c.root().__class__()
>>> c.add(o)
>>> transaction.savepoint()
>>> c.get_connection('2').root.o = o
>>> transaction.savepoint()

and didn't get any errors. Is this still a problem? If so, may I have a test case?