HHH-19868 RowTransformerConstructorImpl throws NullPointerException when TupleMetadata is null

Author: dreab8

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

@@ -291,7 +291,7 @@ protected TupleMetadata buildTupleMetadata(SqmStatement<?> statement, Class<R> r
 		if ( statement instanceof SqmSelectStatement<?> select ) {
 			final List<SqmSelection<?>> selections =
 					select.getQueryPart().getFirstQuerySpec().getSelectClause().getSelections();
-			return isTupleMetadataRequired( resultType, selections.get(0) )
+			return isTupleMetadataRequired( resultType, selections )
 					? getTupleMetadata( selections )
 					: null;
 		}
@@ -300,7 +300,8 @@ protected TupleMetadata buildTupleMetadata(SqmStatement<?> statement, Class<R> r
 		}
 	}
 
-	private static <R> boolean isTupleMetadataRequired(Class<R> resultType, SqmSelection<?> selection) {
+	private static <R> boolean isTupleMetadataRequired(Class<R> resultType, List<SqmSelection<?>> selections) {
+		final var selection = selections.size() == 1 ? selections.get( 0 ) : null;
 		return isHqlTuple( selection )
 			|| !isInstantiableWithoutMetadata( resultType )
 				&& !isSelectionAssignableToResultType( selection, resultType );

hibernate-core/src/main/java/org/hibernate/sql/results/internal/RowTransformerConstructorImpl.java

@@ -6,15 +6,14 @@
 
 import jakarta.persistence.TupleElement;
 import org.hibernate.InstantiationException;
+import org.hibernate.query.sqm.SqmExpressible;
+import org.hibernate.query.sqm.tree.SqmExpressibleAccessor;
 import org.hibernate.sql.results.spi.RowTransformer;
+import org.hibernate.type.spi.TypeConfiguration;
 
 import java.lang.reflect.Constructor;
 import java.util.List;
 
-import org.hibernate.query.sqm.SqmExpressible;
-import org.hibernate.query.sqm.tree.SqmExpressibleAccessor;
-import org.hibernate.type.spi.TypeConfiguration;
-
 import static java.util.stream.Collectors.toList;
 import static org.hibernate.sql.results.graph.instantiation.internal.InstantiationHelper.findMatchingConstructor;
 
@@ -32,6 +31,7 @@ public RowTransformerConstructorImpl(
 			TupleMetadata tupleMetadata,
 			TypeConfiguration typeConfiguration) {
 		this.type = type;
+		assert tupleMetadata != null : "TupleMetadata must not be null";
 		final List<TupleElement<?>> elements = tupleMetadata.getList();
 		final List<Class<?>> argumentTypes = elements.stream()
 				.map( RowTransformerConstructorImpl::resolveElementJavaType )