Question

On our Beijing (2/2003) version of Twiki we've noticed certain scenarios where writers are having their edits accidentally overwritten by subsequent writer. We'ver verified that the problem is related to expiring locks.

An example scenario: Writer1 acquires a lock and starts editing. He holds the lock longer than the lock timeout value so his lock expires. Writer2 acquires a lock on the same topic. Writer2 finishes his edits immediately and checks them in with no errors or warnings (as expected). Writer1 eventually finishes his edits and checks in his changes, CLOBBERING WRITER2's changes but receiving no errors or warnings.

It seems as though the proper behavior would be for twiki to detect that the topic has changed since the time that Writer1 acquired their lock and to notify the user about the conflict.

There is much concern now that users may be accidentally clobbering each others' changes without knowing it.

I searched through the bug topics on twiki.org to see if this behavior has been corrected in subsequent releases, but haven't been able to find anything indicative one way or another. I also searched through the FAQ and docs and Support Web to see if i could find any discussions on this but was unsuccessful.

Is there a solution available for this problem?

Thank you

Environment

-- MichaelBurton - 29 Jun 2005

Answer

There's only one real cure for this well known problem --> migrate to Dakar (resp. Develop for the time being) cause there are no locks anymore. All contributions to a topic will be merged. Potential conflicts are highlighted.

If migration is no option for you, maybe you could try to set the locking time to zero (in TWiki.cfg) and check the RELEASEEDITLOCKCHECKBOX (in your TWikiPreferences). That did help our system a lot. But be aware that it's not guranteed that there's no text clobbering anymore.

-- FranzJosefSilli - 30 Jun 2005