HHH-16281 Inconsistent Behaivor of L2 cache between Hibernate 5 and 6

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/BasicValuedMapping.java

@@ -56,7 +56,13 @@ public interface BasicValuedMapping extends ValueMapping, SqlExpressible {
 	}
 
 	@Override
-	default void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session){
+	default void addToCacheKey(
+			MutableCacheKeyBuilder cacheKey,
+			Object value,
+			SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		final JdbcMapping jdbcMapping = getJdbcMapping();
 		final BasicValueConverter converter = jdbcMapping.getValueConverter();
 		final Serializable disassemble;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/IdClassEmbeddable.java

@@ -320,6 +320,9 @@ public class IdClassEmbeddable extends AbstractEmbeddableMapping implements Iden
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		final Serializable[] result = new Serializable[ getNumberOfAttributeMappings() ];
 		for ( int i = 0; i < result.length; i++ ) {
 			final AttributeMapping attributeMapping = getAttributeMapping( i );

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/SimpleForeignKeyDescriptor.java

@@ -423,6 +423,9 @@ public class SimpleForeignKeyDescriptor implements ForeignKeyDescriptor, BasicVa
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		final JdbcMapping jdbcMapping = getJdbcMapping();
 		final BasicValueConverter converter = jdbcMapping.getValueConverter();
 		final Serializable disassemble;

hibernate-core/src/main/java/org/hibernate/metamodel/model/domain/internal/TupleMappingModelExpressible.java

@@ -44,6 +44,9 @@ public class TupleMappingModelExpressible implements MappingModelExpressible {
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		for ( int i = 0; i < components.length; i++ ) {
 			components[i].addToCacheKey( cacheKey, value, session );
 		}

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleBasicValuedModelPart.java

@@ -317,6 +317,9 @@ public class AnonymousTupleBasicValuedModelPart implements ModelPart, MappingTyp
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		cacheKey.addValue( value );
 		cacheKey.addHashCode( ( (JavaType) getExpressibleJavaType() ).extractHashCode( value ) );
 	}

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/expression/JdbcLiteral.java

@@ -123,6 +123,9 @@ public class JdbcLiteral<T> implements Literal, MappingModelExpressible<T>, Doma
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		final Serializable disassemble = ( (MutabilityPlan<Object>) jdbcMapping.getJdbcJavaType().getMutabilityPlan() )
 				.disassemble( value, session );
 		final int hashCode = jdbcMapping.getJavaTypeDescriptor().extractHashCode( value );

hibernate-core/src/main/java/org/hibernate/sql/exec/internal/AbstractJdbcParameter.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.sql.exec.internal;
 
+import java.io.Serializable;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
@@ -158,20 +159,27 @@ public abstract class AbstractJdbcParameter
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		final JdbcMapping jdbcMapping = getJdbcMapping();
 		final BasicValueConverter converter = jdbcMapping.getValueConverter();
 
+		final Serializable disassemble;
+		final int hashCode;
 		if ( converter == null ) {
 			final JavaType javaTypeDescriptor = jdbcMapping.getJavaTypeDescriptor();
-			cacheKey.addValue( javaTypeDescriptor.getMutabilityPlan().disassemble( value, session ) );
+			disassemble = javaTypeDescriptor.getMutabilityPlan().disassemble( value, session );
-			cacheKey.addHashCode( javaTypeDescriptor.extractHashCode( value ) );
+			hashCode = javaTypeDescriptor.extractHashCode( value );
 		}
 		else {
 			final Object relationalValue = converter.toRelationalValue( value );
 			final JavaType relationalJavaType = converter.getRelationalJavaType();
-			cacheKey.addValue( relationalJavaType.getMutabilityPlan().disassemble( relationalValue, session ) );
+			disassemble = relationalJavaType.getMutabilityPlan().disassemble( relationalValue, session );
-			cacheKey.addHashCode( relationalJavaType.extractHashCode( relationalValue ) );
+			hashCode = relationalJavaType.extractHashCode( relationalValue );
 		}
+		cacheKey.addValue( disassemble );
+		cacheKey.addHashCode( hashCode );
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/type/CustomType.java

@@ -220,6 +220,9 @@ public class CustomType<J>
 
 	@Override
 	public void addToCacheKey(MutableCacheKeyBuilder cacheKey, Object value, SharedSessionContractImplementor session) {
+		if ( value == null ) {
+			return;
+		}
 		final Serializable disassembled = getUserType().disassemble( (J) value );
 		// Since UserType#disassemble is an optional operation,
 		// we have to handle the fact that it could produce a null value,

hibernate-core/src/test/java/org/hibernate/orm/test/cache/QueryCacheWithObjectParameterTest.java

@@ -95,6 +95,44 @@ public class QueryCacheWithObjectParameterTest {
 		);
 	}
 
+	@Test
+	public void testQueryWithEmbeddableParameterWithANull(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					evictQueryRegion( session );
+					Query<Parent> queryParent = session.createQuery(
+							"from Parent p where p.address = :address",
+							Parent.class
+					);
+					queryParent.setParameter( "address", new Address( "via Milano", null ) );
+					queryParent.setCacheable( true );
+
+					List<Parent> resultList = queryParent.getResultList();
+					assertThat( resultList ).hasSize( 0 );
+
+					CacheRegionStatistics defaultQueryCacheRegionStatistics = getQueryCacheRegionStatistics( session );
+					assertThat( defaultQueryCacheRegionStatistics.getHitCount() ).isEqualTo( 0 );
+				}
+		);
+
+		scope.inTransaction(
+				session -> {
+					Query<Parent> queryParent = session.createQuery(
+							"from Parent p where p.address = :address",
+							Parent.class
+					);
+					queryParent.setParameter( "address", new Address( "via Milano", null ) );
+					queryParent.setCacheable( true );
+
+					List<Parent> resultList = queryParent.getResultList();
+					assertThat( resultList ).hasSize( 0 );
+
+					CacheRegionStatistics defaultQueryCacheRegionStatistics = getQueryCacheRegionStatistics( session );
+					assertThat( defaultQueryCacheRegionStatistics.getHitCount() ).isEqualTo( 1 );
+				}
+		);
+	}
+
 	@Test
 	public void testQueryCacheHits(SessionFactoryScope scope) {
 		scope.inTransaction(
@@ -189,6 +227,56 @@ public class QueryCacheWithObjectParameterTest {
 		);
 	}
 
+	@Test
+	public void testQueryCacheHitsNullParameter(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					evictQueryRegion( session );
+					Query<Parent> queryParent = session.createQuery(
+							"from Parent p where p.name = 'John'",
+							Parent.class
+					);
+					List<Parent> p = queryParent.getResultList();
+					assertThat( p ).hasSize( 1 );
+
+					Query<Child> queryChildren = session.createQuery(
+							"from Child c where c.parent.id = ?1",
+							Child.class
+					);
+					queryChildren.setParameter( 1, null );
+					queryChildren.setCacheable( true );
+					List<Child> c = queryChildren.getResultList();
+					assertThat( c ).hasSize( 0 );
+
+					CacheRegionStatistics defaultQueryCacheRegionStatistics = getQueryCacheRegionStatistics( session );
+					assertThat( defaultQueryCacheRegionStatistics.getHitCount() ).isEqualTo( 0 );
+				}
+		);
+
+		scope.inTransaction(
+				session -> {
+					Query<Parent> queryParent = session.createQuery(
+							"from Parent p where p.name = 'John'",
+							Parent.class
+					);
+					List<Parent> p = queryParent.getResultList();
+					assertThat( p ).hasSize( 1 );
+
+					Query<Child> queryChildren = session.createQuery(
+							"from Child c where c.parent.id = ?1",
+							Child.class
+					);
+					queryChildren.setParameter( 1, null );
+					queryChildren.setCacheable( true );
+					List<Child> c = queryChildren.getResultList();
+					assertThat( c ).hasSize( 0 );
+
+					CacheRegionStatistics defaultQueryCacheRegionStatistics = getQueryCacheRegionStatistics( session );
+					assertThat( defaultQueryCacheRegionStatistics.getHitCount() ).isEqualTo( 1 );
+				}
+		);
+	}
+
 	private static void evictQueryRegion(SessionImplementor session) {
 		session.getSessionFactory()
 				.getCache()