How to handle simultaneous editing and deletion of nodes? This is a slightly different version of the question about what happens when two people are editing and saving the same node.  My version involves node deletion instead of editing:


Alice starts to edit the node (/node/123/edit).
Bob starts to edit the same node (/node/123/edit)
Alice deletes node 123 via the Delete button on the form and the followup "are you sure" page.
Bob, not knowing the node has been deleted, hits the Save button on the form.


Currently, Bob gets a 404 error back from the server -- "The requested page '/node/123/edit' could not be found."  This makes good sense, since the node has in fact gone away, but in a perfect world I would trap the doomed request and send back something a little more helpful, perhaps redirecting the user to a more reasonable page.  Is there any way to do this, short of major surgery on the forms API?  I can't think of one, to be honest -- it's the web server here that's unhappy, not Drupal -- but I thought I'd ask...  Maybe there's a hook out there that I don't know about?
A better solution may be to use content locking to prevent double editing.

for example: http://drupal.org/project/content_lock