Hi. _register method of TM class in Shared/DC/ZRDB/TM.py hides all exceptions.
This makes descendants of this class prone to get stuck in a "registered" state withtout any possibility of them to get commited. To reproduce the problem: - create a class inheriting from TM, and define a method calling register. Add logs to abort and commit method to track transaction end. - create a default error page which triggers a call to the method created above. (this is equivalent to accessing some database from the error page, for example) Call it twice. Most realistic case is using an instance surviving the transaction (a global, or a persistant object) - tigger an error in TPC (a raise in vote is the most realistic case) and get the error page to render. The most obvious breakage I could see is when trying to undo an non-undoable transaction (modify a script twice, undo the oldest without undoing the newest) Here is what happens: - first transaction (the "undo" in my example) raises in TPC, transaction is marked as failed - error message gets rendered in the same transaction (that's a ZPublisher bug, but I think the problem "root" is hiding the failure) - error message tries to register itself to transaction manager: First try gets an exception (hidden in TM._register), but in the process transaction's "_adapters" dict was modified. TM subclass instance is not marked as registered. Second try, now there is no exception raised, because transaction's "join" is not called (because of _adapters content). Now the TM subclass instance is marked as registered, but unknown to transaction (_adapters will not be used to commit). The variant with just one call to TM._register "only" causes the instance to be commited at next transaction using it. Is there any reason why TM._register is hiding exceptions ? -- Vincent Pelletier _______________________________________________ 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
