[ZODB-Dev] Strange lookup error...

[B. B.]

Hello,

I have just subscribed this list, to describe a strange error that occured
for me. In the bugtrack people seem to be very precise in describing where
the error is, I have no idea about where the error is, so I will not polute
the bugtrack :-)
I am sorry if writing to this list is not the right thing to do, feel free
to guide me then :-).


Background:
-----------------------
After update of
 - an application, with some modules being renamed
 - python from 2.5 to 2.6
 - zodb
an updatescript is called to refresh the broken objects.
The objects are stored in dict of type <class
'zope.container.contained.ContainedProxy'> with a simple unicode key to the
object mapping.
The refresh of a broken object precedure is :
- identify broken object
- identify correct type
- create an instance of that type
- transfer state from the broken object to the new instance
- reassign the new object in the dict. ( myDict[ id ] = newInstance )
-----------------------


Observation:
-----------------------
Within the same transaction as the broken objects are refreshed, I can
verify that I can lookup all objects..
After a commit, and close / open of the connection, I can not lookup some
objects.
But if I make a list of all items like :

allItems = list( myDict.items() )

all ids and objects are represented in the allItems, and NO objects are
broken, they look all fine.
But for some ids amongst the allItems, "myDict[ id ]" throws a KeyError (
and "id in myDict" returns False )...

It is about 25 objects or so out of a few tusind that fails.... I can not
see anything special with those objects
The FileStorage is last updated with a zodb3 version 3.8.0
-----------------------


The precedure is used to work fine, I have tried with different version of
zodb3 from pypi,

#bad zodb3 = 3.9.2
#bad zodb3 = 3.9.1
#bad zodb3 = 3.9.0
#bad zodb3 = 3.9.0c2
#ok zodb3 = 3.9.0c1
#ok zodb3 = 3.9.0b5
#ok zodb3 = 3.9.0a12

and it says, until version 3.9.0c1, it worked, but with 3.9.0c2 it started
to fail.


System  Linux :
 - Python 2.6.2
 - uname -iorm -> 2.6.27-gentoo-r8 x86_64 AuthenticAMD GNU/Linux


Am I violating some rules of migration, or is it a bug introduced by version
3.9.0c2??

If it is an interesting bug to catch ( for me it is very interesting :-) ),
I can test versions or patches.



Best Regards

Brian
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