[Zope] problem migrating ZClasses from Zope 2.6.1 to Zope 2.9.8

[Yuri]

Dieter Maurer wrote:
> Yuri wrote at 2008-3-26 11:19 +0100:
>   
>> I've got a trouble importing a ZClass app to 2.9.8 from 2.6.1.
>>
>> First, I've tried 2.8, and it worked but had the __new__ problem, so 
>> I've seen it is fixed in 2.9.8.
>>
>> After the upgrade, all seemed to work. My ZClass is a container (with 
>> ExtFile). I've been able to create a new instance, then had trouble 
>> after uploading an ExtFile. The file is there, in the repository, but 
>> when I clicked over it, I get a fast scrolling in the log. After the 
>> restart, the ZClass instances and the Product in the control panel, 
>> gived me a maximun recursion depth, here the last part:
>>
>>  File "/usr/lib/zope2.9.8/lib/python/ZODB/serialize.py", line 597, in 
>> getState
>>    return unpickler.load()
>> ....
>>  File "logging/__init__.py", line 1078, in _log
>>  File "logging/__init__.py", line 1064, in makeRecord
>>  File "logging/__init__.py", line 226, in __init__
>>    # Must happen after ZopeStarter.setupInitialLogging()
>> RuntimeError: maximum recursion depth exceeded in cmp
>>     
>
> This is very strange: the traceback you show does not seem very deep.
> It should not raise a "maximum recursion depth exceeded".
>   


I deleted the long first part, always equal to the last one. Does it 
matter? :)

> As always: when you see something which should not be there, debugging
> may be necessary for understanding...
>   

 I agree. But it works, until you restart then this error happen forever.

 How can I debug this?