[Zope] A persistent problem -- monkey patch related?

[Dieter Maurer]

Dennis Allison wrote at 2004-1-23 13:13 -0800:
>
>The observed behavior (as always, transient and irreproducable from test
>cases) is that the contents of a PersitentMapping object disappears.  The
>underlying structure is a PersistentMapping of PersistentMappings of
>User objects.  My understanding is that the PersistentMapping wrapper
>handles the black magic properly.  As for the perilious modification of 
>mutable attributes, I am certainly aware of the issue--in fact, that's why
>I am so concerned about the monkey patch issue as it is in the monkey
>patch code that the PersistentMapping constructor is called, etc.

Recently, a packing bug has been detected ("FileStorage") which
can lead to data loss. It is triggered when a pack tries to
pack to a time before the pack time of an earlier pack.

When you detect the loss before history information has
been removed by a pack, you can reconstruct the content
of earlier versions (and at least determine when the loss
occured -- this may give some hints with respect to the cause).
I posted some (low level!) routines to "mailto:zope-dev at zope.org"
or "mailto:zodb-dev at zope.org" that makes this a bit easier (--> archives).


Almost surely (I am convinced, but I know your trust
in me is limited :-) ), monkey patching does not affect whether
or not persistent object changes are lost...


-- 
Dieter