[Zope-CMF] CMFUid isn't generating real uids

[Christian Heimes]

Hello everybody!

I had a short look at CMFUid because I hoped we could replace the AT uid 
generator and lookup tool with a more general tool that's also working 
with non Archtypes types. I was disapointed to shocked as I saw how the 
uids are generated.

It's just an incremental counter which is more likely a very simplistic 
id generator but not a real uid generator. It's not likely that other 
portals are using the same uid, it's a FACT because every portal is 
starting the with id 0. IMO that's not unique.
In Archetypes we are also including informations about the machine in 
the uid to create uuid (universal unique ids). The uuid is created from 
the local host name, a time stamp, a random value and from abitrary 
arguments and the output of md5.md5(data).hexdigest() is used as uid. 
This makes it mathematical nearly impossible to have one uid twice over 
all cmf based sites on earth.

A good uid should follow these rules (from the manual of uuidgen)
DESCRIPTION
        The  uuidgen  program  creates  a  new universally unique
        identifier (UUID)
        using the libuuid(3) library.  The new UUID can  reasonably  be
        considered
        unique among all UUIDs created on the local system, and among
        UUIDs created
        on other systems in the past and in the future

Christian