Re: Resource vs. Revision Properties

From: Geoffrey M. Clemm (geoffrey.clemm@rational.com)
Date: Mon, May 01 2000

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    Date: Mon, 1 May 2000 12:58:11 -0400 (EDT)
    Message-Id: <200005011658.MAA11048@tantalum.atria.com>
    From: "Geoffrey M. Clemm" <geoffrey.clemm@rational.com>
    To: ietf-dav-versioning@w3.org
    Subject: Re: Resource vs. Revision Properties
    
       From: "Tim Ellison/OTT/OTI" <Tim_Ellison@oti.com>
    
       <jimd>
       I have 2 concerns:
    
       1) If the revision history is multi-tipped (i.e., there are
       unmerged working tips), the revision selection behavior is not
       deterministic as described.  Which tip is selected?
    
       2) In such a case, the forwardgoing structure still won't be linear, which
       seems to be the intent of this property.
    
       OTOH, if a history is non-linear, but the current state is a single
       tip, the property works as I believe it's intended - to prevent
       future bracnhing.  That situation ought to be just fine.
       </jimd>
    
       <tim_2 weasel="on"> Depends upon the functionality that is
       desirable.  My understanding is that it intended to prevent >1
       working resource for a given versioned resource, and thereby avoid
       the merging problem (i.e., serialize updates).  However, this
       property pre-dates me, so I'll leave it up to one of the protocol
       doc authors to defend it ;-)
    
       As a potential client, DAV:single-checkout is more interesting to
       me since it avoids merging problems.  As a potential server,
       DAV:linear is more interesting, since I can use it to implement DAV
       on a non-branching store.  <tim_2>
    
    The "single checkout" doesn't actually avoid merging, since if you
    checkout a non-latest revision, a client might reasonably want to
    merge that with the revisions that were later than the one that you
    checked out.  So I still vote for JimD's suggestion for a "single tip"
    semantics for DAV:linear.
    
    Cheers,
    Geoff