Initial working support for building and executing JdbcSelect operation from simple HQL for a converted (enum) value - actually reading;

fixed (temporary) support for writing enumerated values

hibernate-core/src/main/java/org/hibernate/boot/model/convert/spi/JpaAttributeConverterCreationContext.java

@@ -8,6 +8,7 @@ package org.hibernate.boot.model.convert.spi;
 
 import org.hibernate.resource.beans.spi.ManagedBeanRegistry;
 import org.hibernate.type.descriptor.java.spi.JavaTypeDescriptorRegistry;
+import org.hibernate.type.spi.TypeConfiguration;
 
 /**
  * Access to information that implementors of
@@ -18,5 +19,9 @@ import org.hibernate.type.descriptor.java.spi.JavaTypeDescriptorRegistry;
  */
 public interface JpaAttributeConverterCreationContext {
 	ManagedBeanRegistry getManagedBeanRegistry();
-	JavaTypeDescriptorRegistry getJavaTypeDescriptorRegistry();
+	TypeConfiguration getTypeConfiguration();
+
+	default JavaTypeDescriptorRegistry getJavaTypeDescriptorRegistry() {
+		return getTypeConfiguration().getJavaTypeDescriptorRegistry();
+	}
 }

hibernate-core/src/main/java/org/hibernate/mapping/BasicValue.java

@@ -42,7 +42,6 @@ import org.hibernate.type.descriptor.java.MutabilityPlan;
 import org.hibernate.type.descriptor.java.PrimitiveByteArrayTypeDescriptor;
 import org.hibernate.type.descriptor.java.RowVersionTypeDescriptor;
 import org.hibernate.type.descriptor.java.TemporalJavaTypeDescriptor;
-import org.hibernate.type.descriptor.java.spi.JavaTypeDescriptorRegistry;
 import org.hibernate.type.descriptor.sql.SqlTypeDescriptor;
 import org.hibernate.type.descriptor.sql.SqlTypeDescriptorIndicators;
 import org.hibernate.type.spi.TypeConfiguration;
@@ -239,8 +238,8 @@ public class BasicValue extends SimpleValue implements SqlTypeDescriptorIndicato
 			}
 
 			@Override
-			public JavaTypeDescriptorRegistry getJavaTypeDescriptorRegistry() {
+			public TypeConfiguration getTypeConfiguration() {
-				return typeConfiguration.getJavaTypeDescriptorRegistry();
+				return typeConfiguration;
 			}
 		};
 
@@ -408,8 +407,8 @@ public class BasicValue extends SimpleValue implements SqlTypeDescriptorIndicato
 								}
 
 								@Override
-								public JavaTypeDescriptorRegistry getJavaTypeDescriptorRegistry() {
+								public TypeConfiguration getTypeConfiguration() {
-									return typeConfiguration.getJavaTypeDescriptorRegistry();
+									return typeConfiguration;
 								}
 							}
 					)

hibernate-core/src/main/java/org/hibernate/mapping/SimpleValue.java

@@ -44,8 +44,6 @@ import org.hibernate.internal.util.ReflectHelper;
 import org.hibernate.metamodel.model.convert.spi.JpaAttributeConverter;
 import org.hibernate.resource.beans.spi.ManagedBeanRegistry;
 import org.hibernate.service.ServiceRegistry;
-import org.hibernate.type.BinaryType;
-import org.hibernate.type.RowVersionType;
 import org.hibernate.type.Type;
 import org.hibernate.type.descriptor.JdbcTypeNameMapper;
 import org.hibernate.type.descriptor.converter.AttributeConverterSqlTypeDescriptorAdapter;
@@ -54,6 +52,7 @@ import org.hibernate.type.descriptor.java.BasicJavaDescriptor;
 import org.hibernate.type.descriptor.sql.LobTypeMappings;
 import org.hibernate.type.descriptor.sql.NationalizedTypeMappings;
 import org.hibernate.type.descriptor.sql.SqlTypeDescriptor;
+import org.hibernate.type.spi.TypeConfiguration;
 import org.hibernate.usertype.DynamicParameterizedType;
 
 /**
@@ -579,8 +578,8 @@ public abstract class SimpleValue implements KeyValue {
 					}
 
 					@Override
-					public org.hibernate.type.descriptor.java.spi.JavaTypeDescriptorRegistry getJavaTypeDescriptorRegistry() {
+					public TypeConfiguration getTypeConfiguration() {
-						return metadata.getTypeConfiguration().getJavaTypeDescriptorRegistry();
+						return getMetadata().getTypeConfiguration();
 					}
 				}
 		);

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/JdbcMapping.java

@@ -29,6 +29,7 @@ public interface JdbcMapping {
 	 */
 	SqlTypeDescriptor getSqlTypeDescriptor();
 
+
 	/**
 	 * The strategy for extracting values of this expressable
 	 * type from JDBC ResultSets, CallableStatements, etc

hibernate-core/src/main/java/org/hibernate/metamodel/model/convert/spi/EnumValueConverter.java

@@ -11,6 +11,8 @@ import java.sql.SQLException;
 
 import org.hibernate.annotations.Remove;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.hibernate.sql.ast.tree.select.SelectStatement;
+import org.hibernate.sql.exec.spi.JdbcOperation;
 import org.hibernate.type.descriptor.java.EnumJavaTypeDescriptor;
 
 /**
@@ -26,7 +28,14 @@ public interface EnumValueConverter<O extends Enum, R> extends BasicValueConvert
 
 	String toSqlLiteral(Object value);
 
+	/**
+	 * @since 6.0
+	 *
+	 * @deprecated Added temporarily in support of dual SQL execution until fully migrated
+	 * to {@link SelectStatement} and {@link JdbcOperation}
+	 */
 	@Remove
+	@Deprecated
 	void writeValue(
 			PreparedStatement statement,
 			Enum value,

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -137,6 +137,7 @@ import org.hibernate.metamodel.mapping.internal.BasicValuedSingularAttributeMapp
 import org.hibernate.metamodel.mapping.internal.InFlightEntityMappingType;
 import org.hibernate.metamodel.mapping.internal.MappingModelCreationHelper;
 import org.hibernate.metamodel.mapping.internal.MappingModelCreationProcess;
+import org.hibernate.metamodel.model.convert.spi.BasicValueConverter;
 import org.hibernate.metamodel.model.domain.NavigableRole;
 import org.hibernate.persister.collection.CollectionPersister;
 import org.hibernate.persister.spi.PersisterCreationContext;
@@ -6056,14 +6057,38 @@ public abstract class AbstractEntityPersister
 		final String[] attrColumnNames = getPropertyColumnNames( propertyIndex );
 
 		if ( attrType instanceof BasicType ) {
-			return new BasicValuedSingularAttributeMapping(
+			final BasicValue.Resolution<?> resolution = ( (BasicValue) bootProperty.getValue() ).resolve();
-					attrName,
+			final BasicValueConverter valueConverter = resolution.getValueConverter();
-					tableExpression,
+
-					attrColumnNames[0],
+			if ( valueConverter != null ) {
-					( (BasicValue) bootProperty.getValue() ).resolve().getValueConverter(),
+				// we want to "decompose" the "type" into its various pieces as expected by the mapping
-					(BasicType) attrType,
+				assert valueConverter.getRelationalJavaDescriptor() == resolution.getRelationalJavaDescriptor();
-					(BasicType) attrType
+
-			);
+				final BasicType<?> mappingBasicType = creationProcess.getCreationContext()
+						.getDomainModel()
+						.getTypeConfiguration()
+						.getBasicTypeRegistry()
+						.resolve( valueConverter.getRelationalJavaDescriptor(), resolution.getRelationalSqlTypeDescriptor() );
+
+				return new BasicValuedSingularAttributeMapping(
+						attrName,
+						tableExpression,
+						attrColumnNames[0],
+						valueConverter,
+						mappingBasicType,
+						mappingBasicType.getJdbcMapping()
+				);
+			}
+			else {
+				return new BasicValuedSingularAttributeMapping(
+						attrName,
+						tableExpression,
+						attrColumnNames[0],
+						null,
+						(BasicType) attrType,
+						(BasicType) attrType
+				);
+			}
 		}
 
 		// todo (6.0) : for now ignore any non basic-typed attributes

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/expression/ColumnReference.java

@@ -68,9 +68,7 @@ public class ColumnReference implements Expression {
 		// todo (6.0) : potential use for runtime database model - interpretation of table and column references
 		//		into metadata info such as java/sql type, binder, extractor
 
-		final ValueExtractor jdbcValueExtractor = jdbcMapping.getJdbcValueExtractor();
+		return new SqlSelectionImpl( jdbcPosition, valuesArrayPosition, this, jdbcMapping );
-
-		return new SqlSelectionImpl( jdbcPosition, valuesArrayPosition, this, jdbcValueExtractor );
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/results/internal/SqlSelectionImpl.java

@@ -9,29 +9,42 @@ package org.hibernate.sql.results.internal;
 import java.util.Objects;
 
 import org.hibernate.metamodel.mapping.JdbcMapping;
+import org.hibernate.metamodel.mapping.SqlExpressable;
 import org.hibernate.sql.ast.spi.SqlAstWalker;
 import org.hibernate.sql.ast.spi.SqlSelection;
 import org.hibernate.sql.ast.tree.expression.Expression;
 import org.hibernate.type.descriptor.ValueExtractor;
 
 /**
+ * @asciidoc
+ *
+ * ````
+ * @Entity
+ * class MyEntity {
+ *     ...
+ *     @Column( name = "the_column", ... )
+ *     public String getTheColumn() { ... }
+ *
+ *     @Convert( ... )
+ *     @Column( name = "the_column", ... )
+ *     ConvertedType getTheConvertedColumn() { ... }
+ *
+ * }
+ * ````
+ *
  * @author Steve Ebersole
  */
 public class SqlSelectionImpl implements SqlSelection {
 	private final int jdbcPosition;
 	private final int valuesArrayPosition;
 	private final Expression sqlExpression;
-	private final ValueExtractor jdbcValueExtractor;
+	private final JdbcMapping jdbcMapping;
 
 	public SqlSelectionImpl(int jdbcPosition, int valuesArrayPosition, Expression sqlExpression, JdbcMapping jdbcMapping) {
-		this( jdbcPosition, valuesArrayPosition, sqlExpression, jdbcMapping.getJdbcValueExtractor() );
-	}
-
-	public SqlSelectionImpl(int jdbcPosition, int valuesArrayPosition, Expression sqlExpression, ValueExtractor jdbcValueExtractor) {
 		this.jdbcPosition = jdbcPosition;
 		this.valuesArrayPosition = valuesArrayPosition;
 		this.sqlExpression = sqlExpression;
-		this.jdbcValueExtractor = jdbcValueExtractor;
+		this.jdbcMapping = jdbcMapping;
 	}
 
 	public Expression getWrappedSqlExpression() {
@@ -40,7 +53,9 @@ public class SqlSelectionImpl implements SqlSelection {
 
 	@Override
 	public ValueExtractor getJdbcValueExtractor() {
-		return jdbcValueExtractor;
+		return ( (SqlExpressable) sqlExpression.getExpressionType() ).getJdbcMapping().getJdbcValueExtractor();
+//		return jdbcValueExtractor;
+//		return jdbcMapping.getJdbcValueExtractor();
 	}
 
 	@Override

hibernate-core/src/test/java/org/hibernate/orm/test/sql/exec/SmokeTests.java

@@ -11,6 +11,7 @@ import java.util.List;
 
 import org.hibernate.cfg.AvailableSettings;
 import org.hibernate.orm.test.metamodel.mapping.SmokeTests.SimpleEntity;
+import org.hibernate.orm.test.metamodel.mapping.SmokeTests.Gender;
 import org.hibernate.query.spi.QueryImplementor;
 
 import org.hibernate.testing.orm.junit.DomainModel;
@@ -86,6 +87,21 @@ public class SmokeTests {
 		);
 	}
 
+	@Test
+	public void testSelectGenderHql(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					final QueryImplementor<Gender> query = session.createQuery(
+							"select e.gender from SimpleEntity e",
+							Gender.class
+					);
+					List<Gender> simpleEntities = query.list();
+					assertThat( simpleEntities.size(), is( 1 ) );
+					assertThat( simpleEntities.get( 0 ), is( FEMALE ) );
+				}
+		);
+	}
+
 	@Test
 	@FailureExpected( reason = "Support for entity-values DomainResults not yet implemented")
 	public void testSelectEntityHqlExecution(SessionFactoryScope scope) {