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RE: [XML Schema 1.1] Using doc() in xs:assert ... the referenced document needs a schema?

From: Michael Kay <mike@saxonica.com>
Date: Fri, 1 May 2009 12:24:34 +0100
To: "'Rick Jelliffe'" <rjelliffe@allette.com.au>, <xmlschema-dev@w3.org>
Message-ID: <7370726B5BBC47EBAD3D358DE19BDF08@Sealion>
> > I think the working group felt that
> > introducing context-dependent validation (where the validity of a 
> > document depends on factors other than the schema and the instance 
> > document) was a risky architectural innovation, and possibly a step 
> > that would be later regretted.
> 
> So they actually had no reason? Just some vague possibility. 

Actually, now I recall some of the discussion: one of the concerns was
specifically the subject of this original question. Should the referenced
document be schema-validated? If so, how do you prevent circularities, or
infinite regress? Some members of the WG feel strongly that validation
should never pose any denial-of-service risks, and allowing doc() opens up
all sorts of possibilities.

Potential problems like this can consume an immense amount of WG time, and
when a spec is running years late already, there is a strong temptation for
the chair to encourage people to cut a feature rather than spend time
discussing whether or not it creates a problem.

Michael Kay
http://www.saxonica.com/
Received on Friday, 1 May 2009 11:25:12 GMT

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