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Bug 2826 - RQ-135 Consistency and validity for a set of schema components (component-consistency-and-validity)
Summary: RQ-135 Consistency and validity for a set of schema components (component-con...
Status: RESOLVED LATER
Alias: None
Product: XML Schema
Classification: Unclassified
Component: Structures: XSD Part 1 (show other bugs)
Version: 1.1 only
Hardware: Other All
: P4 normal
Target Milestone: ---
Assignee: C. M. Sperberg-McQueen
QA Contact: XML Schema comments list
URL:
Whiteboard: important, hard, composition cluster
Keywords:
Depends on:
Blocks:
 
Reported: 2006-02-11 00:57 UTC by C. M. Sperberg-McQueen
Modified: 2007-05-02 00:07 UTC (History)
0 users

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Description C. M. Sperberg-McQueen 2006-02-11 00:57:43 UTC 
This issue was originally reported by Matthew Fuchs.

On 10 June 2004 the WG adopted the following wording for this
requirement:

Eliminate errors at a distance.  A legal schema remains legal if you
add components to it, unless the components you add are themselves
faulty or try to redefine components already present.

The original wording follows:

  We call a set of schema components "valid" if it is transitively
  closed over references and contains no errors.

  We call two sets of schema components "consistent" if, for any
  namespace where they contain components from the same namespace, those
  components can be written using exactly the same transfer syntax.

  The proposed requirement is, that given two sets of schema
  components that are both transitively closed over references and
  valid, if they are consistent, then their union is transitively
  closed over references and valid.

Matthew says:

"I believe we currently have this property, or it's violations are so
far at the limit, that no schemas would be affected by the change.  On
the other hand, this is a crucial property for customers, and they
will be _very_, _very_ unhappy if we violate it.  Maybe not right
away, but they will when it starts to affect them."

See
http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2002Nov/0106.html.

This item was discussed in the meetings of 2003-10-24
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2003Oct/0085.html),
2003-12-05
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2003Dec/0043.html),
2004-01-08
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2004Jan/0009.html),
2004-01-15
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2004Feb/0094.html),
and 2004-01-22
(http://www.w3.org/XML/Group/2004/01/xml-schema-ftf-minutes.html).

The WG formed task forces to prepare further work on this item in the
meeting of 2004-02-27
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2004Feb/0141.html).

This item was then discussed further in the meetings of 2004-03-18
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2004Mar/0060.html)
and 2004-05-28
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2004May/0094.html).

This item was classified as an opportunistic desideratum in the
meeting of 2004-06-10
(http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2004Jun/0120.html).
Comment 1 David Ezell 2007-03-28 19:47:20 UTC 
the Working Group lacks consensus not only on this issue, but on a large number of questions which would need to be clarified to make coherent discussion of this topic feasible.
Resolved as LATER.
Comment 2 C. M. Sperberg-McQueen 2007-05-02 00:07:23 UTC 
[Interim report]  I have been trying to find a current email address for 
Matthew Fuchs, the originator of this issue, so that he could be notified 
of the resolution of the issue for XML Schema 1.1, but I have not
succeeded.  I propose to leave this issue as RESOLVED instead of CLOSED
while those efforts continue, and close it only when necessary.