HHH-19396 cannot select the same column twice with different aliases while using cte

hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java

@@ -1915,6 +1915,11 @@ public QuerySpec visitQuerySpec(SqmQuerySpec<?> sqmQuerySpec) {
 		final boolean oldInNestedContext = inNestedContext;
 		inNestedContext = false;
 
+		final boolean originalDeduplicateSelectionItems = deduplicateSelectionItems;
+		sqmQueryPartStack.push( sqmQuerySpec );
+		// In sub-queries, we can never deduplicate the selection items as that might change semantics
+		deduplicateSelectionItems = false;
+
 		final SqlAstQueryPartProcessingStateImpl processingState;
 		if ( trackAliasedNodePositions( sqmQuerySpec ) ) {
 			processingState = new SqlAstQueryPartProcessingStateImpl(
@@ -1936,10 +1941,6 @@ public QuerySpec visitQuerySpec(SqmQuerySpec<?> sqmQuerySpec) {
 			);
 		}
 
-		final boolean originalDeduplicateSelectionItems = deduplicateSelectionItems;
-		sqmQueryPartStack.push( sqmQuerySpec );
-		// In sub-queries, we can never deduplicate the selection items as that might change semantics
-		deduplicateSelectionItems = false;
 		pushProcessingState( processingState );
 		queryTransformers.push( new ArrayList<>() );
 

hibernate-core/src/main/java/org/hibernate/query/sqm/tree/cte/SqmCteTable.java

@@ -12,6 +12,7 @@
 import org.hibernate.query.criteria.JpaCteCriteriaAttribute;
 import org.hibernate.query.criteria.JpaCteCriteriaType;
 import org.hibernate.query.sqm.SqmBindableType;
+import org.hibernate.query.sqm.tree.select.SqmSelectClause;
 import org.hibernate.query.sqm.tuple.internal.AnonymousTupleSimpleSqmPathSource;
 import org.hibernate.query.sqm.tuple.internal.AnonymousTupleType;
 import org.hibernate.query.sqm.tuple.internal.CteTupleTableGroupProducer;
@@ -34,13 +35,14 @@ public class SqmCteTable<T> extends AnonymousTupleType<T> implements JpaCteCrite
 	private SqmCteTable(
 			String name,
 			SqmCteStatement<T> cteStatement,
-			SqmSelectableNode<?>[] sqmSelectableNodes) {
-		super( sqmSelectableNodes );
+			SqmSelectableNode<?>[] sqmSelectableNodes,
+			List<String> aliases) {
+		super( sqmSelectableNodes, aliases );
 		this.name = name;
 		this.cteStatement = cteStatement;
 		final List<SqmCteTableColumn> columns = new ArrayList<>( componentCount() );
 		for ( int i = 0; i < componentCount(); i++ ) {
-			columns.add( new SqmCteTableColumn( this, getComponentName(i), get(i) ) );
+			columns.add( new SqmCteTableColumn( this, aliases.get(i), get(i) ) );
 		}
 		this.columns = columns;
 	}
@@ -49,12 +51,20 @@ public static <X> SqmCteTable<X> createStatementTable(
 			String name,
 			SqmCteStatement<X> cteStatement,
 			SqmSelectQuery<X> selectStatement) {
-		final SqmSelectableNode<?>[] sqmSelectableNodes = selectStatement.getQueryPart()
+		final SqmSelectClause selectClause = selectStatement.getQueryPart()
 				.getFirstQuerySpec()
-				.getSelectClause()
+				.getSelectClause();
+		final SqmSelectableNode<?>[] sqmSelectableNodes = selectClause
 				.getSelectionItems()
 				.toArray( SqmSelectableNode[]::new );
-		return new SqmCteTable<>( name, cteStatement, sqmSelectableNodes );
+		final var aliases = new ArrayList<String>();
+		for (final var selection : selectClause.getSelections()) {
+			final var alias = selection.getAlias();
+			selection.getSelectableNode().visitSubSelectableNodes( node ->
+					aliases.add( alias == null ? node.getAlias() : alias )
+			);
+		}
+		return new SqmCteTable<>( name, cteStatement, sqmSelectableNodes, aliases );
 	}
 
 	@Override

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

@@ -60,6 +60,10 @@ public AnonymousTupleType(SqmSubQuery<T> subQuery) {
 	}
 
 	public AnonymousTupleType(SqmSelectableNode<?>[] components) {
+		this(components, null);
+	}
+
+	public AnonymousTupleType(SqmSelectableNode<?>[] components, List<String> aliases) {
 		expressibles = new SqmBindableType<?>[components.length];
 		componentSourcePaths = new NavigablePath[components.length];
 		for ( int i = 0; i < components.length; i++ ) {
@@ -74,7 +78,10 @@ public AnonymousTupleType(SqmSelectableNode<?>[] components) {
 		componentIndexMap = linkedMapOfSize( components.length );
 		for ( int i = 0; i < components.length; i++ ) {
 			final SqmSelectableNode<?> component = components[i];
-			final String alias = component.getAlias();
+			String alias = aliases == null ? null : aliases.get( i );
+			if ( alias == null ) {
+				alias = component.getAlias();
+			}
 			if ( alias == null ) {
 				throw new SemanticException( "Select item at position " + (i+1) + " in select list has no alias"
 						+ " (aliases are required in CTEs and in subqueries occurring in from clause)" );

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 jakarta.persistence.TupleElement;
+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.Test;
+
+import static java.util.stream.Collectors.toSet;
+import static org.assertj.core.api.Assertions.assertThat;
+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
+	void CTE_with_same_column_selected_twice(SessionFactoryScope scope) {
+		var r = scope.fromSession( session ->
+				session.createSelectionQuery(
+						"WITH S0 AS (SELECT foo AS foo2, foo AS foo FROM Something)" +
+						"SELECT S0_0.foo AS foo FROM S0 AS S0_0",
+						String.class ).getSingleResult() );
+		assertEquals( "a", r );
+	}
+
+	@Test
+	void CTE_with_same_column_selected_twice_some_aliases_removed(SessionFactoryScope scope) {
+		var r = scope.fromSession( session ->
+				session.createSelectionQuery(
+						"WITH S0 AS (SELECT foo AS foo, foo AS foo2 FROM Something)" +
+						"SELECT foo AS foo FROM S0",
+						String.class ).getSingleResult() );
+		assertEquals( "a", r );
+	}
+
+	@Test
+	void simple_query_with_same_column_selected_twice(SessionFactoryScope scope) {
+		var tuple = scope.fromSession( session ->
+				session.createSelectionQuery(
+						"SELECT foo AS foo, foo as foo2 FROM Something",
+						Tuple.class ).getSingleResult() );
+		assertThat( tuple.getElements().stream().map( TupleElement::getAlias ).collect( toSet() ) )
+				.containsExactlyInAnyOrder( "foo", "foo2" );
+	}
+
+	@Entity(name = "Something")
+	static class Something {
+		@Id
+		@GeneratedValue(strategy = GenerationType.IDENTITY)
+		private Long id;
+		private String foo = "a";
+	}
+}