[pmwiki-users] Burnt! Simultaneous edit lost :-(

[pmwiki at ben-amotz.com]

> > Oh. Then I must have misunderstood something drastically. I dimly 
> > remember somebody wrote about losing edits if no diff3 utility is available.
> 
> "diff3" is not the same as "diff".  The page history is generated
> using a PHP version of "diff", which computes the difference between
> two versions of a page.
> 
> Merging of simultaneous edits is performed using "diff3".  If both
> Alice and Bob simultaneously edit the same page, then "diff3"
> uses Alice's copy, Bob's copy, and the original ancestor to produce
> a new version of the page that incorporates both Alice and Bob's changes
> (or flags places where they conflict).
> 
> Computing (and displaying) a page's edit history only requires "diff".  
> Merging two separate branches of edits together requires "diff3".
> 

Just to be clear here about what is currently being experienced when
(diff is available, but not diff3 and) more than one user is editing
the same page:

1. The user who saves first gets the save posted (and recorded in
history)
2. The user who saves second gets only a refreshed edit screen that
displays an empty text box (and a warning that does not identify any
context)
3. If that second saver presses save again, then a blank page is posted
(and recorded in history)
4. When you view the history, you see the first save and then its
deletion, without any record of the intervening additions that the
second saver attempted (in step 2)

Screen shots are available at 
http://pmwiki.org/wiki/Test/SimultaneousEdits

Pico