I have recently upgraded from ZODB 3.2 to 3.5.1. After doing this I
notice that ZEO throws exceptions on commiting a transaction for certain
types of Persistent classes.
Here is the traceback.
File "/usr/lib/python2.4/site-packages/transaction/_transaction.py",
line 389, in commit
self._saveCommitishError() # This raises!
File "/usr/lib/python2.4/site-packages/transaction/_transaction.py",
line 387, in commit
self._commitResources()
File "/usr/lib/python2.4/site-packages/transaction/_transaction.py",
line 440, in _commitResources
rm.tpc_finish(self)
File "/usr/lib/python2.4/site-packages/ZODB/Connection.py", line 679,
in tpc_finish
self._storage.tpc_finish(transaction, callback)
File "/usr/lib/python2.4/site-packages/ZEO/ClientStorage.py", line
974, in tpc_finish
self._update_cache(tid)
File "/usr/lib/python2.4/site-packages/ZEO/ClientStorage.py", line
999, in _update_cache
self._cache.invalidate(oid, version, tid)
File "/usr/lib/python2.4/site-packages/ZEO/cache.py", line 367, in
invalidate
assert tid is not None and cur_tid < tid
AssertionError
I narrowed it down to the problem occuring when I set instance variables
in __getstate__ (called on commit) on a newly created persistent instance.
This only happens when I am using ZEO (ClientStorage) and not when using
ZODB (FileStorage).
The reason I have chosen to override __getstate__ is to update the
Persistent instance with the current username (which I store on the
transaction when I open the connection) and a timestamp so that the
instance knows when it was modified last and which user did it.
The new beforeCommitHook seems to be suited for this kind of work, but
it doesn't give access to the changed objects in the transaction.
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