[Zope] Versions and write conflicts

[Fernstrom, Christer]

Versions in Zope go some way to help controlling concurrent updates to documents, but unfortunately there is a problem: If you work in a version and open a document for editing, the file is not yet locked. It is only after you have done the first save that it becomes locked.

This means that if you open and start changing, somebody else, who is working in another version, may sneak in, open the document, change it, save the changes, and save the version changes without you ever noticing. Then when you finally save and save your version, you wipe out the changes done by the other poor guy. This without anybody noticing.

I have tried to work around the problem by programatically create a version, put the user in the version, and - before opening the management screen - do a manage_edit on the document. This all works fine, but strangely the manage_edit doesn't seem to lock the file, so although it relieves the user of the burden to think about opening a version before start making changes, the problem mentioned above still remains.

      christer