HHH-11569 - Return only distinct elements when query is hinted with EntityGraph

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

@@ -358,7 +358,11 @@ public class QueryTranslatorImpl implements FilterTranslator {
 
 		final QueryNode query = (QueryNode) sqlAst;
 		final boolean hasLimit = queryParameters.getRowSelection() != null && queryParameters.getRowSelection().definesLimits();
-		final boolean needsDistincting = ( query.getSelectClause().isDistinct() || hasLimit ) && containsCollectionFetches();
+		final boolean needsDistincting = (
+				query.getSelectClause().isDistinct() ||
+				getEntityGraphQueryHint() != null ||
+				hasLimit )
+		&& containsCollectionFetches();
 
 		QueryParameters queryParametersToUse;
 		if ( hasLimit && containsCollectionFetches() ) {

hibernate-core/src/test/java/org/hibernate/jpa/test/graphs/Course.java

@@ -0,0 +1,90 @@
+/*
+ * 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.graphs;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.ManyToMany;
+
+import org.hibernate.annotations.Cache;
+import org.hibernate.annotations.CacheConcurrencyStrategy;
+
+@Entity
+@Cache(usage=CacheConcurrencyStrategy.READ_WRITE)
+public class Course {
+	@Id
+	@GeneratedValue
+	private int id;
+	
+	private String name;
+	
+	@ManyToMany(mappedBy="courses", cascade=CascadeType.ALL)
+	private List<Student> students = new ArrayList<>();
+
+	public int getId() {
+		return id;
+	}
+
+	public void setId(int id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public List<Student> getStudents() {
+		return students;
+	}
+
+	public void setStudents(List<Student> students) {
+		this.students = students;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + getId();
+		result = prime * result + ((name == null) ? 0 : name.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		int id = getId();
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Course other = (Course) obj;
+		if (id != other.id)
+			return false;
+		if (name == null) {
+			if (other.name != null)
+				return false;
+		} else if (!name.equals(other.name))
+			return false;
+		return true;
+	}
+
+	@Override
+	public String toString() {
+		return "Course [name=" + name + "]";
+	}
+}

hibernate-core/src/test/java/org/hibernate/jpa/test/graphs/Student.java

@@ -0,0 +1,84 @@
+/*
+ * 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.graphs;
+
+import java.util.Set;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.JoinTable;
+import javax.persistence.ManyToMany;
+import javax.persistence.NamedAttributeNode;
+import javax.persistence.NamedEntityGraph;
+import javax.persistence.NamedEntityGraphs;
+import javax.persistence.NamedQueries;
+import javax.persistence.NamedQuery;
+import javax.persistence.UniqueConstraint;
+
+import org.hibernate.annotations.Cache;
+import org.hibernate.annotations.CacheConcurrencyStrategy;
+
+@Entity
+@Cache(usage=CacheConcurrencyStrategy.READ_WRITE)
+@NamedEntityGraphs({
+	@NamedEntityGraph(
+		name = "Student.Full",
+		attributeNodes = {
+			@NamedAttributeNode(value = "courses")
+		}
+	)
+})
+@NamedQueries({
+	@NamedQuery(name="LIST_OF_STD", query="select std from Student std")
+})
+public class Student {
+	@Id
+	private int id;
+	
+	private String name;
+	
+	@ManyToMany(cascade=CascadeType.PERSIST)
+	@JoinTable(
+		name="STUDENT_COURSES",
+		joinColumns=@JoinColumn(referencedColumnName="ID", name="STUDENT_ID"),
+		inverseJoinColumns=@JoinColumn(referencedColumnName="ID", name="COURSE_ID"),
+		uniqueConstraints={@UniqueConstraint(columnNames={"STUDENT_ID", "COURSE_ID"})}
+	)
+	private Set<Course> courses;
+
+	public int getId() {
+		return id;
+	}
+
+	public void setId(int id) {
+		this.id = id;
+	}
+
+	public Set<Course> getCourses() {
+		return courses;
+	}
+
+	public void setCourses(Set<Course> courses) {
+		this.courses = courses;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	@Override
+	public String toString() {
+		return "Student [name=" + name + "]";
+	}
+}

hibernate-core/src/test/java/org/hibernate/jpa/test/graphs/queryhint/QueryHintEntityGraphTest.java

@@ -6,8 +6,11 @@
  */
 package org.hibernate.jpa.test.graphs.queryhint;
 
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Set;
 import javax.persistence.EntityGraph;
 import javax.persistence.EntityManager;
 import javax.persistence.Query;
@@ -17,15 +20,18 @@ import org.hibernate.Hibernate;
 import org.hibernate.jpa.QueryHints;
 import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
 import org.hibernate.jpa.test.graphs.Company;
+import org.hibernate.jpa.test.graphs.Course;
 import org.hibernate.jpa.test.graphs.Employee;
 import org.hibernate.jpa.test.graphs.Location;
 import org.hibernate.jpa.test.graphs.Manager;
 import org.hibernate.jpa.test.graphs.Market;
+import org.hibernate.jpa.test.graphs.Student;
 
 import org.hibernate.testing.TestForIssue;
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertSame;
@@ -133,11 +139,9 @@ public class QueryHintEntityGraphTest extends BaseEntityManagerFunctionalTestCas
 		query.setHint( QueryHints.HINT_LOADGRAPH, entityGraph );
 		List results = query.getResultList();
 
-		// we expect 3 results:
 		// - 1st will be the Company with location.zip == 11234 with an empty markets collection
-		// - 2nd and 3rd should be the Company with location.zip == 12345
+		// - 2nd should be the Company with location.zip == 12345
-		//   (2nd and 3rd are duplicated because that entity has 2 elements in markets collection
+		assertEquals( 2, results.size() );
-		assertEquals( 3, results.size() );
 
 		Company companyResult = (Company) results.get( 0 );
 		assertFalse( Hibernate.isInitialized( companyResult.employees ) );
@@ -167,8 +171,6 @@ public class QueryHintEntityGraphTest extends BaseEntityManagerFunctionalTestCas
 		assertTrue( Hibernate.isInitialized( companyResult.phoneNumbers ) );
 		assertEquals( 2, companyResult.phoneNumbers.size() );
 
-		assertSame( companyResult, results.get( 2 ) );
-
 		entityManager.getTransaction().commit();
 		entityManager.close();
 	}
@@ -310,6 +312,48 @@ public class QueryHintEntityGraphTest extends BaseEntityManagerFunctionalTestCas
 		entityManager.close();
 	}
 
+	@Test
+	@TestForIssue(jiraKey = "HHH-11569")
+	public void testCollectionSizeLoadedWithGraph() {
+		doInJPA( this::entityManagerFactory, entityManager -> {
+
+			 Student student1 = new Student();
+			 student1.setId( 1 );
+			 student1.setName( "Student 1" );
+			 Student student2 = new Student();
+			 student2.setId( 2 );
+			 student2.setName( "Student 2" );
+
+			 Course course1 = new Course();
+			 course1.setName( "Full Time" );
+			 Course course2 = new Course();
+			 course2.setName( "Part Time" );
+
+			 Set<Course> std1Courses = new HashSet<Course>();
+			 std1Courses.add( course1 );
+			 std1Courses.add( course2 );
+			 student1.setCourses( std1Courses );
+
+			 Set<Course> std2Courses = new HashSet<Course>();
+			 std2Courses.add( course2 );
+			 student2.setCourses( std2Courses );
+
+			 entityManager.persist( student1 );
+			 entityManager.persist( student2 );
+
+		});
+
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			EntityGraph<?> graph = entityManager.getEntityGraph( "Student.Full" );
+
+			List<Student> students = entityManager.createNamedQuery( "LIST_OF_STD", Student.class )
+					.setHint( QueryHints.HINT_FETCHGRAPH, graph )
+					.getResultList();
+
+			assertEquals( 2, students.size() );
+		});
+	}
+
 	@Before
 	public void createData() {
 		EntityManager entityManager = getOrCreateEntityManager();
@@ -348,6 +392,6 @@ public class QueryHintEntityGraphTest extends BaseEntityManagerFunctionalTestCas
 
 	@Override
 	protected Class<?>[] getAnnotatedClasses() {
-		return new Class<?>[] { Company.class, Employee.class, Manager.class, Location.class };
+		return new Class<?>[] { Company.class, Employee.class, Manager.class, Location.class, Course.class, Student.class };
 	}
 }