HHH-9637 : Join is reused when 2 explicit joins are used for the same ToOne association

Author: gbadner

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/DotNode.java

@@ -468,7 +468,7 @@ private void dereferenceEntityJoin(String classAlias, EntityType propertyType, b
 
 		boolean found = elem != null;
 		// even though we might find a pre-existing element by join path, we may not be able to reuse it...
-		boolean useFoundFromElement = found && canReuse( elem );
+		boolean useFoundFromElement = found && canReuse( classAlias, elem );
 
 		if ( !useFoundFromElement ) {
 			// If this is an implied join in a from element, then use the impled join type which is part of the
@@ -517,16 +517,22 @@ private void dereferenceEntityJoin(String classAlias, EntityType propertyType, b
 		setFromElement( elem );    // This 'dot' expression now refers to the resulting from element.
 	}
 
-	private boolean canReuse(FromElement fromElement) {
+	private boolean canReuse(String classAlias, FromElement fromElement) {
 		// if the from-clauses are the same, we can be a little more aggressive in terms of what we reuse
-		if ( fromElement.getFromClause() == getWalker().getCurrentFromClause() ) {
+		if ( fromElement.getFromClause() == getWalker().getCurrentFromClause() &&
+				areSame( classAlias, fromElement.getClassAlias() )) {
 			return true;
 		}
 
 		// otherwise (subquery case) dont reuse the fromElement if we are processing the from-clause of the subquery
 		return getWalker().getCurrentClauseType() != SqlTokenTypes.FROM;
 	}
 
+	private boolean areSame(String alias1, String alias2) {
+		// again, null != null here
+		return !StringHelper.isEmpty( alias1 ) && !StringHelper.isEmpty( alias2 ) && alias1.equals( alias2 );
+	}
+
 	private void setImpliedJoin(FromElement elem) {
 		this.impliedJoin = elem;
 		if ( getFirstChild().getType() == SqlTokenTypes.DOT ) {

hibernate-core/src/test/java/org/hibernate/test/hql/fetchAndJoin/Child.java

@@ -0,0 +1,80 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2015, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.test.hql.fetchAndJoin;
+
+import java.util.HashSet;
+import java.util.Set;
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.OneToMany;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "entity1")
+public class Child {
+	@Id
+	@GeneratedValue
+	private long id;
+
+	@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
+	@JoinColumn
+	private Set<GrandChild> grandChildren = new HashSet<GrandChild>();
+
+	public Child() {
+	}
+
+	public Child(String value) {
+		this.value = value;
+	}
+
+	private String value;
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public Set<GrandChild> getGrandChildren() {
+		return grandChildren;
+	}
+
+	public void setGrandChildren(Set<GrandChild> grandChildren) {
+		this.grandChildren = grandChildren;
+	}
+
+	public String getValue() {
+		return value;
+	}
+
+	public void setValue(String value) {
+		this.value = value;
+	}
+}

hibernate-core/src/test/java/org/hibernate/test/hql/fetchAndJoin/Entity1.java

@@ -0,0 +1,69 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2015, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.test.hql.fetchAndJoin;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "entity1")
+public class Entity1 {
+	@Id
+	@GeneratedValue
+	private long id;
+
+	@ManyToOne
+	@JoinColumn(name="entity2_id", nullable = false)
+	private Entity2 entity2;
+
+	private String value;
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public Entity2 getEntity2() {
+		return entity2;
+	}
+
+	public void setEntity2(Entity2 entity2) {
+		this.entity2 = entity2;
+	}
+
+	public String getValue() {
+		return value;
+	}
+
+	public void setValue(String value) {
+		this.value = value;
+	}
+}

hibernate-core/src/test/java/org/hibernate/test/hql/fetchAndJoin/Entity2.java

@@ -0,0 +1,70 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2015, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.test.hql.fetchAndJoin;
+
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "entity2")
+public class Entity2 {
+	@Id
+	@GeneratedValue
+	private long id;
+
+	@ManyToOne(fetch = FetchType.LAZY)
+	@JoinColumn(name="entity3_id")
+	private Entity3 entity3;
+
+	private String value;
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public Entity3 getEntity3() {
+		return entity3;
+	}
+
+	public void setEntity3(Entity3 entity3) {
+		this.entity3 = entity3;
+	}
+
+	public String getValue() {
+		return value;
+	}
+
+	public void setValue(String value) {
+		this.value = value;
+	}
+}

hibernate-core/src/test/java/org/hibernate/test/hql/fetchAndJoin/Entity3.java

@@ -0,0 +1,56 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2015, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.test.hql.fetchAndJoin;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "entity3")
+public class Entity3 {
+	@Id
+	@GeneratedValue
+	private long id;
+
+	private String value;
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public String getValue() {
+		return value;
+	}
+
+	public void setValue(String value) {
+		this.value = value;
+	}
+
+}

hibernate-core/src/test/java/org/hibernate/test/hql/fetchAndJoin/GrandChild.java

@@ -0,0 +1,65 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2015, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.test.hql.fetchAndJoin;
+
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.OneToMany;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "entity1")
+public class GrandChild {
+	@Id
+	@GeneratedValue
+	private long id;
+
+	private String value;
+
+	public GrandChild() {
+	}
+
+	public GrandChild(String value) {
+		this.value = value;
+	}
+
+	public long getId() {
+		return id;
+	}
+
+	public void setId(long id) {
+		this.id = id;
+	}
+
+	public String getValue() {
+		return value;
+	}
+
+	public void setValue(String value) {
+		this.value = value;
+	}
+}