Fix UnionSublcass polymorphic associations

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/PluralAttributeMappingImpl.java

@@ -617,7 +617,8 @@ public class PluralAttributeMappingImpl extends AbstractAttributeMapping impleme
 
 		final SqlAliasBase sqlAliasBase = aliasBaseGenerator.createSqlAliasBase( getSqlAliasStem() );
 
-		final TableReference primaryTableReference = entityPartDescriptor.getEntityMappingType()
+		final EntityMappingType entityMappingType = entityPartDescriptor.getEntityMappingType();
+		final TableReference primaryTableReference = entityMappingType
 				.createPrimaryTableReference(
 						sqlAliasBase,
 						sqlExpressionResolver,
@@ -630,9 +631,9 @@ public class PluralAttributeMappingImpl extends AbstractAttributeMapping impleme
 				lockMode,
 				primaryTableReference,
 				sqlAliasBase,
-				(tableExpression) -> entityPartDescriptor.getEntityMappingType()
+				(tableExpression) -> entityMappingType
 						.containsTableReference( tableExpression ),
-				(tableExpression, tg) -> entityPartDescriptor.getEntityMappingType().createTableReferenceJoin(
+				(tableExpression, tg) -> entityMappingType.createTableReferenceJoin(
 						tableExpression,
 						sqlAliasBase,
 						primaryTableReference,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/SimpleForeignKeyDescriptor.java

@@ -6,7 +6,6 @@
  */
 package org.hibernate.metamodel.mapping.internal;
 
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.function.Consumer;
@@ -163,10 +162,7 @@ public class SimpleForeignKeyDescriptor implements ForeignKeyDescriptor, BasicVa
 			SqlAstJoinType sqlAstJoinType,
 			SqlExpressionResolver sqlExpressionResolver,
 			SqlAstCreationContext creationContext) {
-		final String rhsTableExpression = rhs.getTableExpression();
+		if ( lhs.getTableReference( keyColumnContainingTable ) != null ) {
-		final String lhsTableExpression = lhs.getTableExpression();
-		if ( lhsTableExpression.equals( keyColumnContainingTable ) ) {
-			assert rhsTableExpression.equals( targetColumnContainingTable );
 			return new ComparisonPredicate(
 					new ColumnReference(
 							lhs,
@@ -184,7 +180,6 @@ public class SimpleForeignKeyDescriptor implements ForeignKeyDescriptor, BasicVa
 			);
 		}
 		else {
-			assert rhsTableExpression.equals( keyColumnContainingTable );
 			return new ComparisonPredicate(
 					new ColumnReference(
 							lhs,

hibernate-core/src/main/java/org/hibernate/persister/entity/UnionSubclassEntityPersister.java

@@ -51,6 +51,7 @@ import org.hibernate.sql.ast.spi.SqlExpressionResolver;
 import org.hibernate.sql.ast.tree.from.TableGroup;
 import org.hibernate.sql.ast.tree.from.TableReference;
 import org.hibernate.sql.ast.tree.from.UnionTableGroup;
+import org.hibernate.sql.ast.tree.from.UnionTableReference;
 import org.hibernate.sql.ast.tree.predicate.Predicate;
 import org.hibernate.type.StandardBasicTypes;
 import org.hibernate.type.Type;
@@ -233,13 +234,20 @@ public class UnionSubclassEntityPersister extends AbstractEntityPersister {
 			SqlAstCreationContext creationContext) {
 		final SqlAliasBase sqlAliasBase = aliasBaseGenerator.createSqlAliasBase( getSqlAliasStem() );
 
-		final TableReference tableReference = new TableReference(
+		final TableReference tableReference = resolvePrimaryTableReference(sqlAliasBase);
+
+		return new UnionTableGroup( navigablePath, tableReference, this );
+	}
+
+	@Override
+	protected TableReference resolvePrimaryTableReference(SqlAliasBase sqlAliasBase) {
+		return new UnionTableReference(
 				getTableName(),
+				subclassSpaces,
 				sqlAliasBase.generateNewAlias(),
 				false,
 				getFactory()
 		);
-		return new UnionTableGroup( navigablePath, tableReference, this );
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/AbstractColumnReferenceQualifier.java

@@ -26,7 +26,7 @@ public abstract class AbstractColumnReferenceQualifier implements ColumnReferenc
 
 	@Override
 	public TableReference resolveTableReference(String tableExpression, Supplier<TableReference> creator) {
-		final TableReference existing = resolveTableReferenceInternal( tableExpression );
+		final TableReference existing = getTableReferenceInternal( tableExpression );
 		if ( existing != null ) {
 			return existing;
 		}
@@ -38,7 +38,7 @@ public abstract class AbstractColumnReferenceQualifier implements ColumnReferenc
 	public TableReference resolveTableReference(String tableExpression) {
 		assert tableExpression != null;
 
-		final TableReference tableReference = resolveTableReferenceInternal( tableExpression );
+		final TableReference tableReference = getTableReferenceInternal( tableExpression );
 		if ( tableReference == null ) {
 			throw new IllegalStateException( "Could not resolve binding for table `" + tableExpression + "`" );
 		}
@@ -48,16 +48,16 @@ public abstract class AbstractColumnReferenceQualifier implements ColumnReferenc
 
 	@Override
 	public TableReference getTableReference(String tableExpression) {
-		return resolveTableReferenceInternal( tableExpression );
+		return getTableReferenceInternal( tableExpression );
 	}
 
-	protected TableReference resolveTableReferenceInternal(String tableExpression) {
+	protected TableReference getTableReferenceInternal(String tableExpression) {
-		if ( getPrimaryTableReference().getTableExpression().equals( tableExpression ) ) {
+		if ( getPrimaryTableReference().getTableReference( tableExpression ) != null) {
 			return getPrimaryTableReference();
 		}
 
 		for ( TableReferenceJoin tableJoin : getTableReferenceJoins() ) {
-			if ( tableJoin.getJoinedTableReference().getTableExpression().equals( tableExpression ) ) {
+			if ( tableJoin.getJoinedTableReference().getTableReference( tableExpression ) != null) {
 				return tableJoin.getJoinedTableReference();
 			}
 		}

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/AbstractTableGroup.java

@@ -104,12 +104,7 @@ public abstract class AbstractTableGroup extends AbstractColumnReferenceQualifie
 
 	@Override
 	public void setTableGroupJoins(Set<TableGroupJoin> joins) {
-		if ( tableGroupJoins == null ) {
+		tableGroupJoins = new HashSet<>( joins );
-			tableGroupJoins = new HashSet<>( joins );
-		}
-		else {
-			tableGroupJoins.addAll( joins );
-		}
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/CompositeTableGroup.java

@@ -75,12 +75,7 @@ public class CompositeTableGroup implements VirtualTableGroup {
 
 	@Override
 	public void setTableGroupJoins(Set<TableGroupJoin> joins) {
-		if ( tableGroupJoins == null ) {
+		tableGroupJoins = new HashSet<>( joins );
-			tableGroupJoins = new HashSet<>( joins );
-		}
-		else {
-			tableGroupJoins.addAll( joins );
-		}
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/StandardTableGroup.java

@@ -94,8 +94,8 @@ public class StandardTableGroup extends AbstractTableGroup {
 	}
 
 	@Override
-	public TableReference resolveTableReferenceInternal(String tableExpression) {
+	public TableReference getTableReferenceInternal(String tableExpression) {
-		final TableReference tableReference = super.resolveTableReferenceInternal( tableExpression );
+		final TableReference tableReference = super.getTableReferenceInternal( tableExpression );
 		if ( tableReference != null ) {
 			return tableReference;
 		}
@@ -105,7 +105,7 @@ public class StandardTableGroup extends AbstractTableGroup {
 				for ( int i = 0; i < tableJoins.size(); i++ ) {
 					final TableReferenceJoin join = tableJoins.get( i );
 					assert join != null;
-					if ( join.getJoinedTableReference().getTableExpression().equals( tableExpression ) ) {
+					if ( join.getJoinedTableReference().getTableReference( tableExpression ) != null ) {
 						return join.getJoinedTableReference();
 					}
 				}
@@ -116,7 +116,7 @@ public class StandardTableGroup extends AbstractTableGroup {
 
 		for ( TableGroupJoin tableGroupJoin : getTableGroupJoins() ) {
 			final TableReference primaryTableReference = tableGroupJoin.getJoinedGroup().getPrimaryTableReference();
-			if ( primaryTableReference.getTableExpression().equals( tableExpression ) ) {
+			if ( primaryTableReference.getTableReference( tableExpression ) != null ) {
 				return primaryTableReference;
 			}
 		}

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/TableGroup.java

@@ -53,6 +53,7 @@ public interface TableGroup extends SqlAstNode, ColumnReferenceQualifier, SqmPat
 	void applyAffectedTableNames(Consumer<String> nameCollector);
 
 	TableReference getPrimaryTableReference();
+
 	List<TableReferenceJoin> getTableReferenceJoins();
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/TableReference.java

@@ -61,7 +61,7 @@ public class TableReference implements SqlAstNode, ColumnReferenceQualifier {
 		if ( tableExpression.equals( getTableExpression() ) ) {
 			return this;
 		}
-		return null;
+		throw new IllegalStateException( "Could not resolve binding for table `" + tableExpression + "`" );
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/UnionTableGroup.java

@@ -7,6 +7,7 @@
 package org.hibernate.sql.ast.tree.from;
 
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.function.Consumer;
@@ -23,6 +24,7 @@ import org.hibernate.query.NavigablePath;
  */
 public class UnionTableGroup implements VirtualTableGroup {
 	private final NavigablePath navigablePath;
+	private Set<TableGroupJoin> tableGroupJoins;
 
 	private final UnionSubclassEntityPersister modelPart;
 	private final TableReference tableReference;
@@ -63,24 +65,32 @@ public class UnionTableGroup implements VirtualTableGroup {
 
 	@Override
 	public Set<TableGroupJoin> getTableGroupJoins() {
-		return Collections.emptySet();
+		return tableGroupJoins == null ? Collections.emptySet() : Collections.unmodifiableSet( tableGroupJoins );
 	}
 
 	@Override
 	public boolean hasTableGroupJoins() {
-		return false;
+		return tableGroupJoins != null && !tableGroupJoins.isEmpty();
 	}
 
 	@Override
 	public void setTableGroupJoins(Set<TableGroupJoin> joins) {
+		tableGroupJoins = new HashSet<>( joins );
 	}
 
 	@Override
 	public void addTableGroupJoin(TableGroupJoin join) {
+		if ( tableGroupJoins == null ) {
+			tableGroupJoins = new HashSet<>();
+		}
+		tableGroupJoins.add( join );
 	}
 
 	@Override
 	public void visitTableGroupJoins(Consumer<TableGroupJoin> consumer) {
+		if ( tableGroupJoins != null ) {
+			tableGroupJoins.forEach( consumer );
+		}
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/UnionTableReference.java

@@ -0,0 +1,54 @@
+/*
+ * 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.sql.ast.tree.from;
+
+import org.hibernate.engine.spi.SessionFactoryImplementor;
+
+/**
+ * @author Andrea Boriero
+ */
+public class UnionTableReference extends TableReference {
+	private final String[] subclassTableSpaceExpressions;
+
+	public UnionTableReference(
+			String unionTableExpression,
+			String[] subclassTableSpaceExpressions,
+			String identificationVariable,
+			boolean isOptional,
+			SessionFactoryImplementor sessionFactory) {
+		super( unionTableExpression, identificationVariable, isOptional, sessionFactory );
+
+		this.subclassTableSpaceExpressions = subclassTableSpaceExpressions;
+	}
+
+	public TableReference resolveTableReference(String tableExpression) {
+		if ( hasTableExpression( tableExpression ) ) {
+			return this;
+		}
+		throw new IllegalStateException( "Could not resolve binding for table `" + tableExpression + "`" );
+	}
+
+	@Override
+	public TableReference getTableReference(String tableExpression) {
+		if ( hasTableExpression( tableExpression ) ) {
+			return this;
+		}
+		return null;
+	}
+
+	private boolean hasTableExpression(String tableExpression) {
+		if ( tableExpression.equals( getTableExpression() ) ) {
+			return true;
+		}
+		for ( String expression : subclassTableSpaceExpressions ) {
+			if ( tableExpression.equals( expression ) ) {
+				return true;
+			}
+		}
+		return false;
+	}
+}

hibernate-core/src/main/java/org/hibernate/sql/results/graph/entity/AbstractEntityInitializer.java

@@ -128,8 +128,8 @@ public abstract class AbstractEntityInitializer extends AbstractFetchParentAcces
 							for ( int i = 0; i < identifierInitializers.size(); i++ ) {
 								final Initializer existing = identifierInitializers.get( i );
 								if ( existing.getNavigablePath().equals( navigablePath )
-										&& fetchedModelPart.getNavigableRole().equals(
+										&& fetchedModelPart.getNavigableRole()
-										existing.getInitializedPart().getNavigableRole() ) ) {
+										.equals( existing.getInitializedPart().getNavigableRole() ) ) {
 									return existing;
 								}
 							}

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/discriminator/TablePerClassInheritanceTest.java

@@ -0,0 +1,297 @@
+/*
+ * 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.orm.test.inheritance.discriminator;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import javax.persistence.DiscriminatorColumn;
+import javax.persistence.DiscriminatorType;
+import javax.persistence.DiscriminatorValue;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Inheritance;
+import javax.persistence.InheritanceType;
+import javax.persistence.OneToMany;
+import javax.persistence.OneToOne;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.orm.junit.DomainModel;
+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 org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.core.Is.is;
+import static org.junit.jupiter.api.Assertions.fail;
+
+/**
+ * @author Davide D'Alto
+ */
+@TestForIssue(jiraKey = "HHH-12332")
+@DomainModel(
+		annotatedClasses = {
+				TablePerClassInheritanceTest.Person.class,
+				TablePerClassInheritanceTest.Child.class,
+				TablePerClassInheritanceTest.Man.class,
+				TablePerClassInheritanceTest.Woman.class
+		}
+)
+@SessionFactory
+public class TablePerClassInheritanceTest {
+	private final Man john = new Man( "John", "Riding Roller Coasters" );
+	private final Woman jane = new Woman( "Jane", "Hippotherapist" );
+	private final Child susan = new Child( "Susan", "Super Mario retro Mushroom" );
+	private final Child mark = new Child( "Mark", "Fidget Spinner" );
+	private final List<Child> children = new ArrayList<>( Arrays.asList( susan, mark ) );
+	private final List<Person> familyMembers = Arrays.asList( john, jane, susan, mark );
+
+	@BeforeEach
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			jane.setHusband( john );
+			jane.setChildren( children );
+
+			john.setWife( jane );
+			john.setChildren( children );
+
+			for ( Child child : children ) {
+				child.setFather( john );
+				child.setMother( jane );
+			}
+
+			for ( Person person : familyMembers ) {
+				session.persist( person );
+			}
+		} );
+
+	}
+
+	@AfterEach
+	public void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					List<Person> people = session.createQuery( "FROM Person p", Person.class ).getResultList();
+					people.forEach( person -> session.delete( person ) );
+
+				}
+		);
+	}
+
+	@Test
+	public void testSelectHierarchyRoot(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			List<Person> people = session.createQuery( "FROM Person p", Person.class ).getResultList();
+			assertThat( people.size(), is( familyMembers.size() ) );
+			for ( Person person : people ) {
+				if ( person instanceof Man ) {
+					assertThat( ( (Man) person ).getHobby(), is( john.getHobby() ) );
+				}
+				else if ( person instanceof Woman ) {
+					assertThat( ( (Woman) person ).getJob(), is( jane.getJob() ) );
+				}
+				else if ( person instanceof Child ) {
+					if ( person.getName().equals( "Susan" ) ) {
+						assertThat( ( (Child) person ).getFavouriteToy(), is( susan.getFavouriteToy() ) );
+					}
+					else {
+						assertThat( ( (Child) person ).getFavouriteToy(), is( mark.getFavouriteToy() ) );
+					}
+				}
+				else {
+					fail( "Unexpected result: " + person );
+				}
+			}
+		} );
+	}
+
+	@Test
+	public void testSelectHierarchyLeaf(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			List<Man> men = session.createQuery( "FROM Man m", Man.class ).getResultList();
+			for ( Man man : men ) {
+				assertThat( man.getHobby(), is( john.getHobby() ) );
+			}
+		} );
+	}
+
+	@Test
+	public void testGetHierarchyLeaf(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			Man man = session.get( Man.class, "John" );
+			assertThat( man.getHobby(), is( john.getHobby() ) );
+		} );
+	}
+
+
+	@Entity(name = "Person")
+	@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
+	@DiscriminatorColumn(name = "TYPE", discriminatorType = DiscriminatorType.STRING)
+	public static class Person {
+
+		@Id
+		private String name;
+
+
+		public Person() {
+		}
+
+		public Person(String name) {
+			this.name = name;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		@Override
+		public String toString() {
+			return name;
+		}
+	}
+
+	@Entity(name = "Child")
+	@DiscriminatorValue("CHILD")
+	public static class Child extends Person {
+
+		private String favouriteToy;
+
+		@OneToOne
+		private Woman mother;
+
+		@OneToOne
+		private Man father;
+
+		public Child() {
+		}
+
+		public Child(String name, String favouriteToy) {
+			super( name );
+			this.favouriteToy = favouriteToy;
+		}
+
+		public String getFavouriteToy() {
+			return favouriteToy;
+		}
+
+		public void setFavouriteToy(String favouriteToy) {
+			this.favouriteToy = favouriteToy;
+		}
+
+		public Man getFather() {
+			return father;
+		}
+
+		public void setFather(Man father) {
+			this.father = father;
+		}
+
+		public Woman getMother() {
+			return mother;
+		}
+
+		public void setMother(Woman mother) {
+			this.mother = mother;
+		}
+	}
+
+	@Entity(name = "Man")
+	@DiscriminatorValue("MAN")
+	public static class Man extends Person {
+
+		private String hobby;
+
+		@OneToOne
+		private Woman wife;
+
+		@OneToMany(mappedBy = "father")
+		private List<Child> children = new ArrayList<>();
+
+		public Man() {
+		}
+
+		public Man(String name, String hobby) {
+			super( name );
+			this.hobby = hobby;
+		}
+
+		public String getHobby() {
+			return hobby;
+		}
+
+		public void setHobby(String hobby) {
+			this.hobby = hobby;
+		}
+
+		public Woman getWife() {
+			return wife;
+		}
+
+		public void setWife(Woman wife) {
+			this.wife = wife;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+	}
+
+	@Entity(name = "Woman")
+	@DiscriminatorValue("WOMAN")
+	public static class Woman extends Person {
+
+		private String job;
+
+		@OneToOne
+		private Man husband;
+
+		@OneToMany(mappedBy = "mother")
+		private List<Child> children = new ArrayList<>();
+
+		public Woman() {
+		}
+
+		public Woman(String name, String job) {
+			super( name );
+			this.job = job;
+		}
+
+		public String getJob() {
+			return job;
+		}
+
+		public void setJob(String job) {
+			this.job = job;
+		}
+
+		public Man getHusband() {
+			return husband;
+		}
+
+		public void setHusband(Man husband) {
+			this.husband = husband;
+		}
+
+		public List<Child> getChildren() {
+			return children;
+		}
+
+		public void setChildren(List<Child> children) {
+			this.children = children;
+		}
+	}
+}