HQL union query with null values in select part

Hibernate ORM
1

I create union query with two tables. This two tables have set of identical columns and set of not identical columns. I want that null values is selected for not identical columns.
I create query as follow (simplified, other columns were ommited):

 List<UnitedAlarmDto> resultList = entityManager.createQuery("""
                SELECT
                ja.jobId as jobId
                from JobAlarm ja
                union all
                SELECT
                null as jobId
                from SystemAlarm sa
                """, Tuple.class)
            .getResultList()
            .stream()
            .map(AlarmService::fromTuple).toList();

This query throws exception:

Caused by: org.hibernate.query.SemanticException: Select items of the same index must have the same java type across all query parts
	at org.hibernate.query.sqm.tree.select.SqmQueryGroup.validateQueryGroupFetchStructure(SqmQueryGroup.java:174) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.query.sqm.tree.select.SqmQueryGroup.validateQueryStructureAndFetchOwners(SqmQueryGroup.java:154) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.query.hql.internal.SemanticQueryBuilder.visitStatement(SemanticQueryBuilder.java:403) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.query.hql.internal.SemanticQueryBuilder.buildSemanticModel(SemanticQueryBuilder.java:311) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.query.hql.internal.StandardHqlTranslator.translate(StandardHqlTranslator.java:71) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.query.internal.QueryInterpretationCacheStandardImpl.createHqlInterpretation(QueryInterpretationCacheStandardImpl.java:165) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.query.internal.QueryInterpretationCacheStandardImpl.resolveHqlInterpretation(QueryInterpretationCacheStandardImpl.java:147) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.internal.AbstractSharedSessionContract.interpretHql(AbstractSharedSessionContract.java:790) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	at org.hibernate.internal.AbstractSharedSessionContract.createQuery(AbstractSharedSessionContract.java:840) ~[hibernate-core-6.4.4.Final.jar:6.4.4.Final]
	... 251 common frames omitted

What is right way to create such query? Is it possible?
Tested on hibernate version: 6.4.4

2

I guess the validation is a bit too strict. Please try to create a reproducer with our test case template and if you are able to reproduce the issue, create a bug ticket in our issue tracker and attach that reproducer.