From 33efabd5976c8e02faf9366679ac4424eeb82897 Mon Sep 17 00:00:00 2001
From: Vlad Mihalcea <mihalcea.vlad@gmail.com>
Date: Wed, 19 Dec 2018 11:27:41 +0200
Subject: [PATCH] HHH-13167 - When omitting the OTHERWISE clause in a CASE
 expression built with Criteria API, Hibernate throws a NullPointerException

---
 .../expression/SearchedCaseExpression.java    | 11 ++--
 .../SearchedCaseExpressionTest.java           | 51 ++++++++++++++++---
 2 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java
index f3e2357deb..8caab31ec3 100644
--- a/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java
+++ b/hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java
@@ -114,9 +114,14 @@ public class SearchedCaseExpression<R>
 					.append( ( (Renderable) whenClause.getResult() ).render( renderingContext ) );
 		}
 
-		caseStatement.append( " else " )
-				.append( ( (Renderable) getOtherwiseResult() ).render( renderingContext ) )
-				.append( " end" );
+		Expression<?> otherwiseResult = getOtherwiseResult();
+
+		if ( otherwiseResult != null ) {
+			caseStatement.append( " else " )
+					.append( ( (Renderable) otherwiseResult ).render( renderingContext ) );
+		}
+
+		caseStatement.append( " end" );
 
 		return caseStatement.toString();
 	}
diff --git a/hibernate-core/src/test/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpressionTest.java b/hibernate-core/src/test/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpressionTest.java
index 228df1c517..c92d60c619 100644
--- a/hibernate-core/src/test/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpressionTest.java
+++ b/hibernate-core/src/test/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpressionTest.java
@@ -24,11 +24,13 @@ import org.hibernate.dialect.PostgreSQL81Dialect;
 
 import org.hibernate.testing.RequiresDialect;
 import org.hibernate.testing.SkipForDialect;
+import org.hibernate.testing.TestForIssue;
 import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
 import org.junit.Assert;
 import org.junit.Test;
 
 import static org.hibernate.testing.transaction.TransactionUtil.doInHibernate;
+import static org.junit.Assert.assertEquals;
 
 /**
  *
@@ -83,14 +85,49 @@ public class SearchedCaseExpressionTest extends BaseCoreFunctionalTestCase {
 
 			Assert.assertNotNull(resultList);
 		} );
-    }
+	}
 
-    @Override
-    protected Class[] getAnnotatedClasses() {
-        return new Class[]{Event.class, EventType.class};
-    }
+	@Test
+	@TestForIssue(jiraKey = "HHH-13167")
+	public void testMissingElseClause() {
+		doInHibernate( this::sessionFactory, session -> {
+			Event event = new Event();
+			event.id = 1L;
+			event.type = EventType.TYPE1;
 
-    @Entity(name = "Event")
+			session.persist( event );
+		} );
+
+		doInHibernate( this::sessionFactory, session -> {
+			CriteriaBuilder cb = session.getCriteriaBuilder();
+
+			CriteriaQuery<Event> criteria = cb.createQuery( Event.class );
+
+			Root<Event> root = criteria.from( Event.class );
+			Path<EventType> type = root.get( "type" );
+
+			Expression<String> caseWhen = cb.<String> selectCase()
+					.when( cb.equal( type, EventType.TYPE1 ), "Matched" );
+
+			criteria.select( root );
+			criteria.where( cb.equal( caseWhen, "Matched" ) );
+
+			Event event = session.createQuery( criteria ).getSingleResult();
+			assertEquals( 1L, (long) event.id );
+		} );
+	}
+
+	@Override
+	protected boolean isCleanupTestDataRequired() {
+		return true;
+	}
+
+	@Override
+	protected Class[] getAnnotatedClasses() {
+		return new Class[]{ Event.class, EventType.class };
+	}
+
+	@Entity(name = "Event")
 	public static class Event {
 
 		@Id
@@ -113,7 +150,7 @@ public class SearchedCaseExpressionTest extends BaseCoreFunctionalTestCase {
 		}
 	}
 
-    public enum EventType {
+	public enum EventType {
 
 		TYPE1, TYPE2, TYPE3