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Re: Core versioning issues and nits

From: Geoffrey M. Clemm <geoffrey.clemm@rational.com>
Date: Sun, 4 Feb 2001 19:45:13 -0500 (EST)
Message-Id: <200102050045.TAA19841@tantalum.atria.com>
To: ietf-dav-versioning@w3.org

   From: "Lisa Dusseault" <lisa@xythos.com>

   > > In 2.9, the root version of a version history "must
   > > not be deleted".  Why is that?

   > "Otherwise you lose a key semantic of a version tree, namely it
   > is connected and every version is reachable from the
   > DAV:root-version.  I don't see that the benefit of allowing
   > deletion of the root version outweighs the benefit of have the
   > version tree be connected."

   Then make the requirement that the version tree be connected.  It's
   quite possible for implementations to meet the requirement that the
   version tree be connected, and provide this valuable functionality
   for clients.

   On the other hand, if you do not require that the version tree be
   connected, then it's quite possible for implementations to end up with
   an unconnected version tree even without deleting the root version.

   I think the point here is to make the requirement state what the client
   needs, rather than what you think is needed in order to get what the
   client needs.

Good point.  I'll delete the precondition and add a postcondition that
says: "following the deletion, there must be a root version that is a
predecessor of all other versions in that version history".  In particular,
this is trivially satisfiable for linear version histories (which I'm
guessing is what Lisa had in mind :-).

Cheers,
Geoff
Received on Sunday, 4 February 2001 19:46:13 GMT

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