HHH-7821 - Clear the entire BatchFetchQueue on flush.

Provide a safe guard against NPE in BatchFetchQueue.getCollectionBatch() by checking that CollectionEntry.getLoadedKey() is not null before adding it to the batch.

hibernate-core/src/test/java/org/hibernate/test/flush/BookStore.java

@@ -0,0 +1,80 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2013, 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.flush;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.ManyToMany;
+
+import org.hibernate.annotations.GenericGenerator;
+
+/**
+ * @author Guillaume Smet
+ */
+@Entity
+public class BookStore {
+
+	private Long id;
+	private String name;
+	private Set<Book> books = new HashSet<Book>();
+
+	public BookStore() {
+	}
+
+	public BookStore(String name) {
+		this.name = name;
+	}
+
+	@Id
+	@GeneratedValue(generator = "increment")
+	@GenericGenerator(name = "increment", strategy = "increment")
+	public Long getId() {
+		return id;
+	}
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	@ManyToMany
+	public Set<Book> getBooks() {
+		return books;
+	}
+
+	public void setBooks(Set<Book> books) {
+		this.books = books;
+	}
+}

hibernate-core/src/test/java/org/hibernate/test/flush/TestClearBatchFetchQueueAfterFlush.java

@@ -0,0 +1,96 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2013, 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.flush;
+
+import java.util.Iterator;
+
+import org.hibernate.Session;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.cfg.Environment;
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Test;
+
+/**
+ * Thanks to Jan Hodac and Laurent Almeras for providing test cases for this
+ * issue.
+ * 
+ * @author Guillaume Smet
+ */
+@TestForIssue(jiraKey = "HHH-7821")
+public class TestClearBatchFetchQueueAfterFlush extends BaseCoreFunctionalTestCase {
+
+	public void configure(Configuration cfg) {
+		cfg.setProperty( Environment.DEFAULT_BATCH_FETCH_SIZE, "10" );
+	}
+
+	@Test
+	public void testClearBatchFetchQueueAfterFlush() {
+		Session s = openSession();
+		s.beginTransaction();
+
+		Author author1 = new Author( "David Lodge" );
+		author1.getBooks().add( new Book( "A Man of Parts", author1 ) );
+		author1.getBooks().add( new Book( "Thinks...", author1 ) );
+		author1.getBooks().add( new Book( "Therapy", author1 ) );
+		s.save( author1 );
+
+		Iterator<Book> bookIterator = author1.getBooks().iterator();
+
+		BookStore bookStore1 = new BookStore( "Passages" );
+		bookStore1.getBooks().add( bookIterator.next() );
+		s.save( bookStore1 );
+
+		BookStore bookStore2 = new BookStore( "Librairie du Tramway" );
+		bookStore2.getBooks().add( bookIterator.next() );
+		s.save( bookStore2 );
+
+		BookStore bookStore3 = new BookStore( "Le Bal des Ardents" );
+		bookStore3.getBooks().add( bookIterator.next() );
+		s.save( bookStore3 );
+
+		s.flush();
+		s.getTransaction().commit();
+		s.clear();
+
+		bookStore1 = (BookStore) s.load( BookStore.class, bookStore1.getId() );
+		bookStore2 = (BookStore) s.load( BookStore.class, bookStore2.getId() );
+		bookStore3 = (BookStore) s.load( BookStore.class, bookStore3.getId() );
+
+		s.beginTransaction();
+		s.delete( bookStore2 );
+		s.getTransaction().commit();
+
+		s.flush();
+
+		bookStore1.getBooks().size();
+		bookStore3.getBooks().size();
+	}
+
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[] { Author.class, Book.class, Publisher.class, BookStore.class };
+	}
+
+}