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Bug 6321 - clarify schema validation behavior when an IF instance contains zero schema documents
Summary: clarify schema validation behavior when an IF instance contains zero schema d...
Status: RESOLVED FIXED
Alias: None
Product: SML
Classification: Unclassified
Component: Interchange Format (show other bugs)
Version: CR
Hardware: PC Windows XP
: P2 normal
Target Milestone: PR
Assignee: Virginia Smith
QA Contact: SML Working Group discussion list
URL:
Whiteboard:
Keywords: resolved
Depends on:
Blocks:
 
Reported: 2008-12-18 21:16 UTC by John Arwe
Modified: 2009-01-13 00:30 UTC (History)
2 users (show)

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Description John Arwe 2008-12-18 21:16:28 UTC
The SML working group asked me to open this bug on behalf of Sandy Gao, who raised the issue privately just before leaving for vacation.  Sandy noted that last week's discussion http://lists.w3.org/Archives/Public/public-sml/2008Dec/att-0030/20081211-sml-minutes.html#item08 indicates a possible need to clarify the working group's intent.  On today's telecon there was consensus that such clarification is in fact needed, and I was asked to draft same.

SMLIF 5.4.3 Schema Bindings currently addresses the question posed in the bug summary in its final paragraph: "Otherwise, if an SML-IF consumer chooses not to process the schemaBindings element, then the SML-IF consumer MUST compose a schema using all schema documents included in the SML-IF document and MUST use this schema to validate all instance documents in the interchange model."

I can see several potential points of clarification here:

(1) "Otherwise, if an SML-IF consumer chooses not to process the schemaBindings element, then..." leaves somewhat unclear that it also applies when an SMLIF consumer that "supports" schema bindings simply finds none in the SMLIF instance.

(2) the distinction between "schema" and "schema document" is perhaps too subtle for ordinary readers unfamiliar with the intricacies of schema processing.

Proposed changes:
(1) 
from: Otherwise, if ... chooses not to ..., then the SML-IF consumer MUST ...
to:   In all other cases,                        the SML-IF consumer MUST ...
   + (add, after end of current sentence, non-normative note)
     "Note: Examples of these cases include:
            1. an SML-IF consumer chooses not to process the schemaBindings 
               element
            2. no schema documents are found amongst the SML-IF document's
               definition documents

(2) Add non-normative note:
Note: The distinction between schema and schema documents is both intentional and important; the absence of schema documents does not imply the absence of a schema.  A schema containing only built-in components will be constructed given zero schema documents as input, and this schema will be used to validate all instance documents in the interchange model.  This distinction has an impact on model validation results according to the definition of validity for a conforming SML model [SML Conformance].

If accepted in toto, the final paragraph of 5.4.3 then changes from

Otherwise, if an SML-IF consumer chooses not to process the schemaBindings element, then the SML-IF consumer MUST compose a schema using all schema documents included in the SML-IF document and MUST use this schema to validate all instance documents in the interchange model.

to

In all other cases, the SML-IF consumer MUST compose a schema using all schema documents included in the SML-IF document and MUST use this schema to validate all instance documents in the interchange model.

Note: Examples of these cases include:
            1. an SML-IF consumer chooses not to process the schemaBindings 
               element 
            2. no schema documents are found amongst the SML-IF document's
               definition documents

Note: The distinction between schema and schema documents is both intentional and important; the absence of schema documents does not imply the absence of a schema.  A schema containing only built-in components will be constructed given zero schema documents as input, and this schema will be used to validate all instance documents in the interchange model.  This distinction has an impact on model validation results according to the definition of validity for a conforming SML model [SML Conformance].
Comment 1 C. M. Sperberg-McQueen 2009-01-08 19:41:11 UTC
The WG considered the wording proposal included here at its call of
8 January 2009 and approved it as proposed.  I'm marking the issue as
editorial to signal that the editors need to incorportate the proposal
into the spec source.
Comment 2 Virginia Smith 2009-01-13 00:30:57 UTC
Fixed as proposed in description. See final paragraph (and 2 notes) in section 5.4.3.