[JENA-1018] Variable Scoping Issues

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Jena 3.0.0
• Fix Version/s: Jena 3.0.1
• Component/s: Optimizer
• External issue URL: https://lists.w3.org/Archives/Public/public-sparql-dev/2015JulSep/0026.html
• Assignee: Andy Seaborne
• Reporter: Michael Schmidt
• Created: 01/Sep/15 10:23
• Updated: 12/Dec/15 17:46
• Resolved: 01/Sep/15 12:34

Description

Consider the sample data

<http://example.com/Alice> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.com/Person> .
<http://example.com/Flipper> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.com/Animal> .

and the following three queries:

SELECT ?s ?type WHERE { 
  BIND("http://example.com/" AS ?typeBase)
  {
    BIND(URI(CONCAT(?typeBase,"Person")) AS ?type)
   ?s ?p ?o
   FILTER(?o=?type)
  }
}

SELECT ?s ?type WHERE { 
  BIND("http://example.com/" AS ?typeBase)
  {
    BIND(URI(CONCAT(?typeBase,"Person")) AS ?type)
    ?s ?p ?o
    FILTER(?o=?type)
  }
  UNION
  {
    BIND(URI(CONCAT(?typeBase,"Animal")) AS ?type)
    ?s ?p ?o
    FILTER(?o=?type)
  }
}

 SELECT ?s ?type WHERE {
   {
     BIND(URI(CONCAT(?typeBase,"Person")) AS ?type)
     ?s a ?o
     FILTER(?o=?type)
   }
   UNION
   {
     BIND(URI(CONCAT(?typeBase,"Animal")) AS ?type)
     ?s a ?o
     FILTER(?o=?type)
   }
 } VALUES (?typeBase) { ("http://example.com/") }

As discussed in thread https://lists.w3.org/Archives/Public/public-sparql-dev/2015JulSep/0026.html, in all cases variable ?typeBase is not in scope when binding variable ?type. As a consequence, all queries should return the empty result. However, with apache-jena-3.0.0 (tested with sparql batch script) all of them yield non-empty results.

Issue Links

• relates to: JENA-1028 2.3.1-snapshot fails with OpDisjunction / org.apache.jena.atlas.lib.NotImplemented