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Re: Clarification on what exactly is captured in the Baseline Collect ion...

From: Tim Ellison <Tim_Ellison@uk.ibm.com>
Date: Thu, 27 Sep 2001 14:31:08 +0100
To: ietf-dav-versioning@w3.org
Message-ID: <OF69BFF333.7CFA1ED7-ON80256AD4.004A0BA1@portsmouth.uk.ibm.com>

The baseline collection is deep, for example, it is the collection
structure that you would see if you initialized a new workspace from that
baseline.

The confusion may have arisen since a 'baseline of a collection' (i.e., not
a baseline-collection, <sigh>) is a non-collection resource.  Terminology
confusion I think.

Regards,

Tim Ellison
Java Technology Centre, MP146
IBM UK Laboratory, Hursley Park, Winchester, UK. SO21 2JN
tel: +44 (0)1962 819872  internal: 249872  MOBx: 270452


                                                                                                             
                    Peter Raymond                                                                            
                    <Peter.Raymond@merant.co       To:     ietf-dav-versioning@w3.org                        
                    m>                             cc:                                                       
                    Sent by:                       Subject:     Clarification on what exactly is captured in 
                    ietf-dav-versioning-requ        the Baseline Collect  ion...                             
                    est@w3.org                                                                               
                                                                                                             
                                                                                                             
                    2001-09-27 10:50 AM                                                                      
                    Please respond to Peter                                                                  
                    Raymond                                                                                  
                                                                                                             
                                                                                                             






Hi,

I thought I understood what was captured in the Baseline Collection (the
collection which captures the state of the Baseline-Controlled Collection),
but reading the spec in more detail with others in MERANT some seeds of
doubt have been sown.

Below is a detailed explanation, but I guess the basic question is, given:

build
  |
  + include ---- globals.h

Where build and include are collections and globals.h is a VCR.

Does the Baseline Collection contain either:

1) A binding to a collection where that collection contains a binding to a
   VCR for globals.h.

or

2) One binding called "include/globals.h" which points to the VCR for
globals.h.

Is the Baseline Collection "deep" (containing collections and their
members) or "shallow"
does it only contain VCRs and have "multi-segment" bindings to indicate the
presence
of collections?


Here is my analysis of the specification which shows this is
ambiguous......

Section 12 says:

       "In order to allow efficient baseline implementation, the state of a
        baseline of a collection is limited to be a set of versions and
their
        names relative to the collection"

Is it a set of versions or a set of VCRs pointing to versions?  I thought
it was the
latter.  Section 12.3.1 describes the members of the Baseline Collection to
be VCRs
not versions.

In the postcondition DAV:select-existing-baseline it also talks about VCRs
being
created for each "version in the baseline", this gives the impression that
versions
(not VCRs) are captured by the baseline collection.

Are the bindings to the VCRs in the Baseline Collection "multi-segment", eg
build/src/gui/main.c or does the Baseline Collection capture the
collections that
were members of the original collection?

We talk about the baseline capturing the state of the version-controlled
members
of a collection, but does it actually also capture the state of the
collections
that are in the configuration rooted at the baseline-controlled collection?

I think the bindings are "multi-segment" and the Baseline Collection is
"flat",
the only hint to this is in the DAV:select-existing-baseline postcondition
where it says that "Any nested collections that are needed to provide the
appropriate name for a version-controlled member will be created", this
hints
that the baseline collection did not contain collections, it contained
"multi-segment" bindings and now collections need to be created.

But the DAV:create-new-baseline postcondition says:

       "The DAV:baseline-collection of the new baseline MUST identify a
        collection whose members have the same relative name and
        DAV:checked-in version as the version-controlled members of the
        request collection"

This hints that the bindings are relative names (same as in the original
collection).

So I would say the specification is ambiguous.  If we can clarify this I
will
happily update the deltaV FAQ to include a good definition of the Baseline
Collection.

Regards,
--
Peter Raymond - MERANT
Principal Architect (PVCS)
Tel: +44 (0)1727 813362
Fax: +44 (0)1727 869804
mailto:Peter.Raymond@merant.com
WWW: http://www.merant.com
Received on Thursday, 27 September 2001 09:32:18 GMT

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