HHH-13111 Restore support of criteria subqueries in select clauses

When the JPA query compliance mode is disabled (the default), it should
be possible to include subqueries in select clauses of a criteria query.

This was previously accepted due to a bug. After having fixed HHH-13001, we
started to throw an IllegalStateException.

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/CriteriaSubqueryImpl.java

@@ -258,8 +258,12 @@ public class CriteriaSubqueryImpl<T> extends ExpressionImpl<T> implements Subque
 
 	@Override
 	public String render(RenderingContext renderingContext) {
-		if ( renderingContext.getClauseStack().getCurrent() == Clause.SELECT ) {
-			throw new IllegalStateException( "Subquery cannot occur in select clause" );
+		if ( criteriaBuilder().getEntityManagerFactory().getSessionFactoryOptions().getJpaCompliance()
+				.isJpaQueryComplianceEnabled() &&
+				renderingContext.getClauseStack().getCurrent() == Clause.SELECT ) {
+			throw new IllegalStateException(
+					"The JPA specification does not support subqueries in select clauses. " +
+							"Please disable the JPA query compliance if you want to use this feature." );
 		}
 
 		StringBuilder subqueryBuffer = new StringBuilder( "(" );

hibernate-core/src/test/java/org/hibernate/jpa/test/criteria/subquery/AbstractSubqueryInSelectClauseTest.java

@@ -0,0 +1,108 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.jpa.test.criteria.subquery;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.persistence.CollectionTable;
+import javax.persistence.ElementCollection;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.MapKeyColumn;
+import javax.persistence.OneToMany;
+
+import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+import org.junit.Before;
+
+public abstract class AbstractSubqueryInSelectClauseTest extends BaseEntityManagerFunctionalTestCase {
+
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[]{ Person.class, Document.class };
+	}
+
+	@Before
+	public void initData() {
+		doInJPA( this::entityManagerFactory, em -> {
+			Person p1 = new Person();
+			Person p2 = new Person();
+			Document d = new Document();
+
+			p1.getLocalized().put( 1, "p1.1" );
+			p1.getLocalized().put( 2, "p1.2" );
+			p2.getLocalized().put( 1, "p2.1" );
+			p2.getLocalized().put( 2, "p2.2" );
+
+			d.getContacts().put( 1, p1 );
+			d.getContacts().put( 2, p2 );
+
+			em.persist( p1 );
+			em.persist( p2 );
+			em.persist( d );
+		} );
+	}
+
+	@Entity(name = "Document")
+	public static class Document {
+
+		private Integer id;
+
+		private Map<Integer, Person> contacts = new HashMap<Integer, Person>();
+
+		@Id
+		@GeneratedValue
+		public Integer getId() {
+			return id;
+		}
+
+		public void setId(Integer id) {
+			this.id = id;
+		}
+
+		@OneToMany
+		@CollectionTable
+		@MapKeyColumn(name = "position")
+		public Map<Integer, Person> getContacts() {
+			return contacts;
+		}
+
+		public void setContacts(Map<Integer, Person> contacts) {
+			this.contacts = contacts;
+		}
+	}
+
+	@Entity(name = "Person")
+	public static class Person {
+
+		private Integer id;
+
+		private Map<Integer, String> localized = new HashMap<Integer, String>();
+
+		@Id
+		@GeneratedValue
+		public Integer getId() {
+			return id;
+		}
+
+		public void setId(Integer id) {
+			this.id = id;
+		}
+
+		@ElementCollection
+		public Map<Integer, String> getLocalized() {
+			return localized;
+		}
+
+		public void setLocalized(Map<Integer, String> localized) {
+			this.localized = localized;
+		}
+	}
+}

hibernate-core/src/test/java/org/hibernate/jpa/test/criteria/subquery/SubqueryInSelectClauseJpaComplianceTest.java

@@ -0,0 +1,51 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.jpa.test.criteria.subquery;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
+
+import java.util.Map;
+
+import javax.persistence.Tuple;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Join;
+import javax.persistence.criteria.JoinType;
+import javax.persistence.criteria.Root;
+import javax.persistence.criteria.Subquery;
+
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.testing.TestForIssue;
+import org.junit.Test;
+
+@TestForIssue(jiraKey = "HHH-13111")
+public class SubqueryInSelectClauseJpaComplianceTest extends AbstractSubqueryInSelectClauseTest {
+
+	@Override
+	@SuppressWarnings({ "unchecked", "rawtypes" })
+	protected void addConfigOptions(Map options) {
+		options.put( AvailableSettings.JPA_QUERY_COMPLIANCE, true );
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void testSubqueryInSelectClause() {
+		doInJPA( this::entityManagerFactory, em -> {
+			CriteriaBuilder cb = em.getCriteriaBuilder();
+			CriteriaQuery<Tuple> query = cb.createTupleQuery();
+			Root<Document> document = query.from( Document.class );
+			Join<?, ?> contacts = document.join( "contacts", JoinType.LEFT );
+
+			Subquery<Long> personCount = query.subquery( Long.class );
+			Root<Person> person = personCount.from( Person.class );
+			personCount.select( cb.count( person ) ).where( cb.equal( contacts.get( "id" ), person.get( "id" ) ) );
+
+			query.multiselect( document.get( "id" ), personCount.getSelection() );
+
+			em.createQuery( query ).getResultList();
+		} );
+	}
+}

hibernate-core/src/test/java/org/hibernate/jpa/test/criteria/subquery/SubqueryInSelectClauseTest.java

@@ -0,0 +1,46 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.jpa.test.criteria.subquery;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import javax.persistence.Tuple;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Join;
+import javax.persistence.criteria.JoinType;
+import javax.persistence.criteria.Root;
+import javax.persistence.criteria.Subquery;
+
+import org.hibernate.testing.TestForIssue;
+import org.junit.Test;
+
+@TestForIssue(jiraKey = "HHH-13111")
+public class SubqueryInSelectClauseTest extends AbstractSubqueryInSelectClauseTest {
+
+	@Test
+	public void testSubqueryInSelectClause() {
+		doInJPA( this::entityManagerFactory, em -> {
+			CriteriaBuilder cb = em.getCriteriaBuilder();
+			CriteriaQuery<Tuple> query = cb.createTupleQuery();
+			Root<Document> document = query.from( Document.class );
+			Join<?, ?> contacts = document.join( "contacts", JoinType.LEFT );
+
+			Subquery<Long> personCount = query.subquery( Long.class );
+			Root<Person> person = personCount.from( Person.class );
+			personCount.select( cb.count( person ) ).where( cb.equal( contacts.get( "id" ), person.get( "id" ) ) );
+
+			query.multiselect( document.get( "id" ), personCount.getSelection() );
+
+			List<?> l = em.createQuery( query ).getResultList();
+			assertEquals( 2, l.size() );
+		} );
+	}
+}