HHH-19396 Test case - selecting same column (under different alias) twice in same (sub)query

Author: cigaly

hibernate-core/src/test/java/org/hibernate/orm/test/subquery/MultipleIdenticalColumnsInSubqueryTest.java

@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.subquery;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Tuple;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+@DomainModel(annotatedClasses = MultipleIdenticalColumnsInSubqueryTest.Something.class)
+@SessionFactory
+@JiraKey("HHH-19396")
+class MultipleIdenticalColumnsInSubqueryTest {
+
+	@BeforeEach
+	void init(SessionFactoryScope scope) {
+		scope.inTransaction( session -> session.persist( new Something() ) );
+	}
+
+	@AfterEach
+	void clean(SessionFactoryScope scope) {
+		scope.inTransaction( session -> session.createMutationQuery( "delete from Something" ).executeUpdate() );
+	}
+
+	@Test
+	@DisplayName("Temporary table with same column selected twice, deduplication should be turned off")
+	void CTE_with_same_column_selected_twice(SessionFactoryScope scope) {
+		var r = scope.fromSession( session ->
+				session.createSelectionQuery(
+						"WITH S0 AS (SELECT foo AS foo, foo AS bar FROM Something) SELECT foo AS foo FROM S0",
+						String.class ).getSingleResult() );
+		assertEquals( "a", r );
+	}
+
+	@Test
+	@DisplayName("Subquery with same column selected twice, deduplication should be turned off")
+	void CTE_with_same_column_selected_twice_some_aliases_removed(SessionFactoryScope scope) {
+		var r = scope.fromSession( session ->
+				session.createSelectionQuery(
+						"SELECT foo AS foo FROM (SELECT foo AS foo, foo AS foo2 FROM Something)",
+						String.class ).getSingleResult() );
+		assertEquals( "a", r );
+	}
+
+	@Test
+	@DisplayName("Simple query with same column selected twice, deduplication should be turned on")
+	void simple_query_with_same_column_selected_twice(SessionFactoryScope scope) {
+		var tuple = scope.fromSession( session ->
+				session.createSelectionQuery(
+						"SELECT foo AS foo, foo as bar FROM Something",
+						Tuple.class ).getSingleResult() );
+		assertEquals( 2, tuple.getElements().size() );
+		assertEquals( "a", tuple.get( "foo" ) );
+		assertEquals( "a", tuple.get( "bar" ) );
+	}
+
+	@Entity(name = "Something")
+	static class Something {
+		@Id
+		@GeneratedValue(strategy = GenerationType.IDENTITY)
+		private Long id;
+		private String foo = "a";
+	}
+}