I've noticed what may be a regression in MINUS behavior but may be wrong. Long
ago one of our developers wrote the following query as a test case:
SELECT *
WHERE {
?n0 ?n1 ?n2 .
MINUS { <http://www.cray.com/n0-2> <http://www.cray.com/n1-2>
<http://www.cray.com/n2-2> .}
}
I.e. They are minusing a concrete triple pattern from some variables, prior to
ARQ 2.9.2 this worked but from 2.9.2 onwards it doesn't (likely because of Paul
Gearon's changes)
Now I'm not sure if this should ever have worked since the spec says that a
MINUS with no shared variables has no effect. I only discovered the query
(which was buried away in some Spring context – oh joy!) because bumping the
ARQ version to the 2.9.3-SNAPSHOT to pick up some of mine and Andy's recent
SPARQL TSV improvements caused this test to start failing.
What is the expected behavior in this case?
If this is a regression can someone open a bug and take a look at fixing this,
if this isn't a bug and the new ARQ behavior is actually now correct let me
know as a query like this should be added to the DAWG test suite so I'll send a
formal comment (unless Paul/Andy just want to propose this at the next WG
telecom themselves?)
Cheers,
Rob
