HHH-13216 Fix BigDecimal handling in criteria queries

We used to lose some precision when dealing with BigDecimals.

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/ValueHandlerFactory.java

@@ -195,6 +195,12 @@ public class ValueHandlerFactory {
 			if ( value == null ) {
 				return null;
 			}
+			if ( BigInteger.class.isInstance( value ) ) {
+				return (BigInteger) value;
+			}
+			if ( BigDecimal.class.isInstance( value ) ) {
+				return ( (BigDecimal) value ).toBigInteger();
+			}
 			if ( Number.class.isInstance( value ) ) {
 				return BigInteger.valueOf( ( (Number) value ).longValue() );
 			}
@@ -216,6 +222,9 @@ public class ValueHandlerFactory {
 			if ( value == null ) {
 				return null;
 			}
+			if ( BigDecimal.class.isInstance( value ) ) {
+				return (BigDecimal) value;
+			}
 			if ( BigInteger.class.isInstance( value ) ) {
 				return new BigDecimal( (BigInteger) value );
 			}

hibernate-core/src/test/java/org/hibernate/test/type/BigDecimalTypeTest.java

@@ -0,0 +1,106 @@
+/*
+ * 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.test.type;
+
+import org.hibernate.Session;
+import org.hibernate.query.Query;
+import org.hibernate.resource.transaction.spi.TransactionStatus;
+import org.hibernate.testing.junit4.BaseNonConfigCoreFunctionalTestCase;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.fail;
+
+import java.math.BigDecimal;
+import javax.persistence.Basic;
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Root;
+
+/**
+ * @author Ales Justin
+ */
+public class BigDecimalTypeTest extends BaseNonConfigCoreFunctionalTestCase {
+	@Override
+	protected Class[] getAnnotatedClasses() {
+		return new Class[] {Account.class};
+	}
+
+	@Test
+	public void testBigDecimalInSum() {
+		final BigDecimal balance = new BigDecimal("1000000000.00000004");
+
+		Session s = openSession();
+		s.getTransaction().begin();
+		try {
+			Account account = new Account();
+			account.id = 1L;
+			account.balance = balance;
+
+			s.save( account );
+			s.getTransaction().commit();
+		}
+		catch (Exception e) {
+			if ( s.getTransaction() != null && s.getTransaction().getStatus() == TransactionStatus.ACTIVE ) {
+				s.getTransaction().rollback();
+			}
+			fail( e.getMessage() );
+		}
+		finally {
+			s.close();
+		}
+
+		s = openSession();
+		s.getTransaction().begin();
+		try {
+			CriteriaBuilder b = s.getCriteriaBuilder();
+
+			CriteriaQuery<BigDecimal> cq = b.createQuery(BigDecimal.class);
+			Root<Account> account_ = cq.from(Account.class);
+
+			cq.select(b.sum(account_.get("balance")));
+
+			Query<BigDecimal> query = s.createQuery(cq);
+
+			BigDecimal result = s.createQuery("SELECT SUM(a.balance) FROM Account a", BigDecimal.class).uniqueResult();
+			Assert.assertEquals(0, balance.compareTo(result));
+
+			result = query.uniqueResult();
+			Assert.assertEquals(0, balance.compareTo(result));
+
+			s.getTransaction().commit();
+		}
+		catch (Exception e) {
+			if ( s.getTransaction() != null && s.getTransaction().getStatus() == TransactionStatus.ACTIVE ) {
+				s.getTransaction().rollback();
+			}
+			fail( e.getMessage() );
+		}
+		finally {
+			s.close();
+		}
+	}
+
+	@Entity(name = "Account")
+	public static class Account {
+
+		@Id
+		private Long id;
+
+		@Basic(optional = false)
+		@Column(precision = 20, scale = 8)
+		private BigDecimal balance;
+	}
+
+	@Override
+	protected boolean isCleanupTestDataRequired() {
+		return true;
+	}
+}