David Pratt wrote:
There seems to be enough of a difference between Z2 and Z3 undo to have
an effect on a backend like PGStorage from working on Z3. I believe the
objective in the storage api is that it should not matter to the backend
whether you are connected to Z2 or Z3. Can someone more familiar with
the history of undo in z2 and z3 explain the current situation?
Undo has a fairly complicated API, and I can easily believe that Z2 and
Z3 call that API in very different ways.
BTW, I strongly discourage use of Undo except in emergencies.
Sadly, except when undoing the last (non-undo) transactions in
a database can lead to inconsistency. Undo should be used with
caution and should generally not be exposed to non-expert users.
In Z3, before bringing up the contents view, there is a check of the
undo transactions for the principal. It uses z3's undo manager to
getPrincipalTransactions which eventually results in a lookup in the
undoLog in the external storage where it dies. Just a brief look at the
undo code in z3 gives me the feeling the format
Format of what?
> between z2 and z3 may be
incompatible which may be the problem.
The relevant portion of the traceback I receive is this:
File "/usr/local/zope3/z3trunk/src/zope/tales/expressions.py", line
199, in _eval
return ob()
File
"/usr/local/zope3/z3trunk/src/zope/app/publisher/browser/viewmeta.py",
line 419, in __call__
return meth(*a, **k)
File "/usr/local/zope3/z3trunk/src/zope/app/undo/browser.py", line 33,
in principalLastTransactionIsUndo
last=1)
File "/usr/local/zope3/z3trunk/src/zope/app/undo/__init__.py", line
108, in getPrincipalTransactions
return self._getUndoInfo(context, principal, first, last)
File "/usr/local/zope3/z3trunk/src/zope/app/undo/__init__.py", line
129, in _getUndoInfo
entries = self.__db.undoInfo(first, last, specification)
File "/usr/local/zope3/z3trunk/src/ZODB/UndoLogCompatible.py", line
37, in undoInfo
return self.undoLog(first, last, filter)
File "/usr/local/zope3/z3trunk/src/ZODB/PGStorage/pgstorage.py", line
478, in undoLog
d.update(cPickle.loads(ext))
You should report this to Shane.
It's possible that there is a bug in PGStorage in handling
extension data. I can easily believe that Z2 doesn't use extension
data and perhaps z3 does.
Jim
--
Jim Fulton mailto:[EMAIL PROTECTED] Python Powered!
CTO (540) 361-1714 http://www.python.org
Zope Corporation http://www.zope.com http://www.zope.org
_______________________________________________
For more information about ZODB, see the ZODB Wiki:
http://www.zope.org/Wikis/ZODB/
ZODB-Dev mailing list - ZODB-Dev@zope.org
http://mail.zope.org/mailman/listinfo/zodb-dev
