[JENA-2333] Sorting by labels in SPARQL query fail

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Jena 2.10.1, Jena 3.16.0, Jena 4.5.0
• Fix Version/s: Jena 4.6.0
• Component/s: ARQ, Jena
• Assignee: Andy Seaborne
• Reporter: Georgy Litvinov
• Created: 17/Jun/22 13:19
• Updated: 25/Aug/22 09:43
• Resolved: 06/Jul/22 12:34

Description

Sorting by labels fail on this data set.

Simple Java example to reproduce attached.

Looks like a race condition involved.

SELECT ?label WHERE {
   ?object <http://www.w3.org/2000/01/rdf-schema#label> ?label . } ORDER BY ASC(?label)

 

java.lang.IllegalArgumentException: Comparison method violates its general contract!
    at java.base/java.util.TimSort.mergeLo(TimSort.java:781)
    at java.base/java.util.TimSort.mergeAt(TimSort.java:518)
    at java.base/java.util.TimSort.mergeCollapse(TimSort.java:448)
    at java.base/java.util.TimSort.sort(TimSort.java:245)
    at java.base/java.util.Arrays.sort(Arrays.java:1441)
    at org.apache.jena.atlas.data.AbortableComparator.abortableSort(AbortableComparator.java:57)
    at org.apache.jena.atlas.data.SortedDataBag.iterator(SortedDataBag.java:205)
    at org.apache.jena.atlas.data.SortedDataBag.iterator(SortedDataBag.java:192)
    at org.apache.jena.sparql.engine.iterator.QueryIterSort$SortedBindingIterator.initializeIterator(QueryIterSort.java:88)
    at org.apache.jena.atlas.iterator.IteratorDelayedInitialization.init(IteratorDelayedInitialization.java:38)
    at org.apache.jena.atlas.iterator.IteratorDelayedInitialization.hasNext(IteratorDelayedInitialization.java:48)
    at org.apache.jena.sparql.engine.iterator.QueryIterPlainWrapper.hasNextBinding(QueryIterPlainWrapper.java:59)
    at org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:114)
    at org.apache.jena.sparql.engine.iterator.QueryIterConvert.hasNextBinding(QueryIterConvert.java:58)
    at org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:114)
    at org.apache.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:38)
    at org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:114)
    at org.apache.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:38)
    at org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:114)
    at org.apache.jena.sparql.exec.RowSetStream.hasNext(RowSetStream.java:47)
    at org.apache.jena.sparql.engine.ResultSetStream.hasNext(ResultSetStream.java:81)
    at test.SortingBug.isReproduced(SortingBug.java:53)
    at test.SortingBug.main(SortingBug.java:39)

Issue Links

• links to: GitHub Pull Request #1404
• links to: GitHub Pull Request #1406