HHH-9745 - ClassCastException in hbm2ddl update and validate

Author: sebersole

hibernate-core/src/main/java/org/hibernate/engine/jdbc/dialect/internal/DialectFactoryImpl.java

@@ -46,29 +46,42 @@ public void setDialectResolver(DialectResolver dialectResolver) {
 
 	@Override
 	public Dialect buildDialect(Map configValues, DialectResolutionInfoSource resolutionInfoSource) throws HibernateException {
-		final String dialectName = (String) configValues.get( AvailableSettings.DIALECT );
-		if ( !StringHelper.isEmpty( dialectName ) ) {
-			return constructDialect( dialectName );
+		final Object dialectReference = configValues.get( AvailableSettings.DIALECT );
+		if ( !isEmpty( dialectReference ) ) {
+			return constructDialect( dialectReference );
 		}
 		else {
 			return determineDialect( resolutionInfoSource );
 		}
 	}
 
-	private Dialect constructDialect(String dialectName) {
+	@SuppressWarnings("SimplifiableIfStatement")
+	private boolean isEmpty(Object dialectReference) {
+		if ( dialectReference != null ) {
+			// the referenced value is not null
+			if ( dialectReference instanceof String ) {
+				// if it is a String, it might still be empty though...
+				return StringHelper.isEmpty( (String) dialectReference );
+			}
+			return false;
+		}
+		return true;
+	}
+
+	private Dialect constructDialect(Object dialectReference) {
 		final Dialect dialect;
 		try {
-			dialect = strategySelector.resolveStrategy( Dialect.class, dialectName );
+			dialect = strategySelector.resolveStrategy( Dialect.class, dialectReference );
 			if ( dialect == null ) {
-				throw new HibernateException( "Unable to construct requested dialect [" + dialectName+ "]" );
+				throw new HibernateException( "Unable to construct requested dialect [" + dialectReference + "]" );
 			}
 			return dialect;
 		}
 		catch (HibernateException e) {
 			throw e;
 		}
 		catch (Exception e) {
-			throw new HibernateException( "Unable to construct requested dialect [" + dialectName+ "]", e );
+			throw new HibernateException( "Unable to construct requested dialect [" + dialectReference + "]", e );
 		}
 	}
 

hibernate-core/src/main/java/org/hibernate/tool/schema/extract/internal/SequenceInformationExtractorNoOpImpl.java

@@ -25,6 +25,6 @@ public class SequenceInformationExtractorNoOpImpl implements SequenceInformation
 	@Override
 	@SuppressWarnings("unchecked")
 	public Iterable<SequenceInformation> extractMetadata(ExtractionContext extractionContext) throws SQLException {
-		return (Iterable<SequenceInformation>) Collections.emptyList().iterator();
+		return Collections.emptyList();
 	}
 }

hibernate-core/src/test/java/org/hibernate/test/schemaupdate/SequenceReadingTest.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.test.schemaupdate;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.registry.StandardServiceRegistry;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.boot.spi.MetadataImplementor;
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.dialect.H2Dialect;
+import org.hibernate.tool.hbm2ddl.SchemaExport;
+import org.hibernate.tool.hbm2ddl.SchemaUpdate;
+import org.hibernate.tool.hbm2ddl.Target;
+import org.hibernate.tool.schema.extract.internal.SequenceInformationExtractorNoOpImpl;
+import org.hibernate.tool.schema.extract.spi.SequenceInformationExtractor;
+
+import org.hibernate.testing.RequiresDialect;
+import org.hibernate.testing.TestForIssue;
+import org.junit.Test;
+
+/**
+ * Regression test fr a bug in org.hibernate.tool.schema.extract.internal.SequenceInformationExtractorNoOpImpl
+ *
+ * @author Steve Ebersole
+ *
+ * @see
+ */
+@TestForIssue( jiraKey = "HHH-9745" )
+public class SequenceReadingTest {
+
+	@Test
+	public void testSequenceReading() {
+		StandardServiceRegistry ssr = new StandardServiceRegistryBuilder()
+				.applySetting( AvailableSettings.DIALECT, MyExtendedH2Dialect.class )
+				.build();
+		try {
+			final MetadataImplementor metadata = (MetadataImplementor) new MetadataSources( ssr )
+					.addAnnotatedClass( MyEntity.class )
+					.buildMetadata();
+			metadata.validate();
+
+			try {
+				// try to update the schema
+				new SchemaUpdate( metadata ).execute( Target.EXPORT );
+			}
+			finally {
+				try {
+					// clean up
+					new SchemaExport( metadata ).drop( Target.EXPORT );
+				}
+				catch (Exception ignore) {
+				}
+			}
+		}
+		finally {
+			StandardServiceRegistryBuilder.destroy( ssr );
+		}
+	}
+
+	/**
+	 * An integral piece of the bug is Dialects which to not support sequence, so lets trick the test
+	 */
+	public static class MyExtendedH2Dialect extends H2Dialect {
+		@Override
+		public SequenceInformationExtractor getSequenceInformationExtractor() {
+			return SequenceInformationExtractorNoOpImpl.INSTANCE;
+		}
+
+		@Override
+		public String getQuerySequencesString() {
+			return null;
+		}
+	}
+
+	@Entity(name = "MyEntity")
+	@Table(name = "my_entity")
+	public static class MyEntity {
+		@Id
+		public Integer id;
+	}
+
+}