HHH-18450 Handle array result types for multi-valued parameters

Also fix an NPE in SqmSelectionQueryImpl#determineResultType

Author: mbellade

hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmSelectionQueryImpl.java

@@ -63,6 +63,7 @@
 import org.hibernate.sql.results.internal.TupleMetadata;
 import org.hibernate.sql.results.spi.ResultsConsumer;
 import org.hibernate.sql.results.spi.SingleResultConsumer;
+import org.hibernate.type.descriptor.java.JavaType;
 
 import static org.hibernate.jpa.HibernateHints.HINT_CACHEABLE;
 import static org.hibernate.jpa.HibernateHints.HINT_CACHE_MODE;
@@ -276,15 +277,15 @@ private static Class<?> determineResultType(SqmSelectStatement<?> sqm, Class<?>
 				return Object[].class;
 			}
 			else {
-				final SqmSelection<?> selection = selections.get(0);
+				final SqmSelection<?> selection = selections.get( 0 );
 				if ( isSelectionAssignableToResultType( selection, expectedResultType ) ) {
-					return selection.getNodeJavaType().getJavaTypeClass();
-				}
-				else {
-					// let's assume there's some
-					// way to instantiate it
-					return expectedResultType;
+					final JavaType<?> nodeJavaType = selection.getNodeJavaType();
+					if ( nodeJavaType != null ) {
+						return nodeJavaType.getJavaTypeClass();
+					}
 				}
+				// let's assume there's some way to instantiate it
+				return expectedResultType;
 			}
 		}
 		else if ( expectedResultType != null ) {

hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmUtil.java

@@ -827,10 +827,19 @@ static JpaOrder sortSpecification(SqmSelectStatement<?> sqm, Order<?> order) {
 	}
 
 	public static boolean isSelectionAssignableToResultType(SqmSelection<?> selection, Class<?> expectedResultType) {
-		if ( expectedResultType == null
-				|| selection != null && selection.getSelectableNode() instanceof SqmParameter ) {
+		if ( expectedResultType == null ) {
 			return true;
 		}
+		else if ( selection != null && selection.getSelectableNode() instanceof SqmParameter ) {
+			// assume the parameter type is assignable to the result type
+			if ( expectedResultType.isArray() ) {
+				final SqmParameter<?> parameter = (SqmParameter<?>) selection.getSelectableNode();
+				return parameter.allowMultiValuedBinding();
+			}
+			else {
+				return true;
+			}
+		}
 		else if ( selection == null
 				|| !isHqlTuple( selection ) && selection.getSelectableNode().isCompoundSelection() ) {
 			return false;