[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-3494) HQLQueryPlan gives back zero result for "getSingleResult()" although one result is available

HQLQueryPlan gives back zero result for "getSingleResult()" although one result is available -------------------------------------------------------------------------------------------- Key: HHH-3494 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3494 Project: Hibernate Core Issue Type: Bug Components: query-hql Affects Versions: 3.3.1 Environment: 3.3.1.GA, hsqldb 1.8.0.7 Reporter: Christian Hofschroer Attachments: patch.txt Original Estimate: 168h Remaining Estimate: 168h I have run the following code snippets both and only the second one works, because there is a bug in HQLQueryPlan. // This does not work correctly (query is javax.persistence.Query) ExampleObject e = (ExampleObject) query.getSingleResult(); // Replacement with this code works List l=query.getResultList() ; assertEquals(1,l.size()) ; ExampleObject e=(ExampleObject)l.get(0) ; This problem occurs only in seldom cases when 1. Hibernate executes several sql queries and merges the result and 2. There is a limit of results (the limit is "2" in version 3.3.1.GA, because only one result is expected anyway) Attached is a patch for the class HQLQueryPlan. The line if ( distinction.add( result ) ) { has to be replaced with if ( ! distinction.add( result ) ) { In case the object was found it returns "true". With the current implementation the object is not added to "combinedResults" although it should be added. It was not possible to reproduce the problem with the setup from "testsuite". If necessary I can provide a JUnit testcase.