logic error in iso draft?

Something that cropped up in testing... I used a random xml document and 
a minimal schema and it was reported as valid. Oops.

The reason was that no assertions failed, because no rules fired (which 
was correct for this schema/instance combination), so there were no 
failed assertions, but no /passed/ assertions either. I checked the 
draft to see if I'd made a mistake with the semantics, and I can't see 
it. Should sec 3.4 should be changed from reading:

"An instance document is valid if no assertion tests in fired rules of 
active patterns fail."
to
"An instance document is valid if no assertion tests in fired rules of 
active patterns fail and at least one rule fires." ?

I can see there might be edge cases where matching 'anything' makes 
sense, but is this really what we mean by a valid document? Or a 'good' 
schema, for that matter - since a well-written schema would have picked 
up that this document wasn't an instance anyway, should a 'good' schema 
also assert that "for all instance, schema, active-phase combinations, 
there exists a subject, pattern and rule, (the subject being a member of 
that instance, the pattern being a member of that schema, the pattern 
being a member of that active-phase, the rule being a member of that 
pattern), for which the subject matches the rule.". Along with the 
schema restrictions that imply a simplified rule contains at least one 
assert or report, this would be enough to ensure that one assertion 
would be tested by the schema for all instances and active phases.

So: should I report no assertions being tested for an instance as a 
valid document, an invalid document, or an error?

-Baz





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