HHH-15912 adaptively choose the DDL type for ORDINAL enums based on the number of members

this amounts to a reversion of HHH-15288 for 99.99% of enums

hibernate-core/src/main/java/org/hibernate/boot/model/process/internal/InferredBasicValueResolver.java

@@ -25,7 +25,6 @@ import org.hibernate.type.AdjustableBasicType;
 import org.hibernate.type.BasicType;
 import org.hibernate.type.CustomType;
 import org.hibernate.type.SerializableType;
-import org.hibernate.type.SqlTypes;
 import org.hibernate.type.descriptor.java.BasicPluralJavaType;
 import org.hibernate.type.descriptor.java.BasicJavaType;
 import org.hibernate.type.descriptor.java.EnumJavaType;
@@ -38,6 +37,9 @@ import org.hibernate.type.descriptor.jdbc.JdbcTypeIndicators;
 import org.hibernate.type.descriptor.jdbc.ObjectJdbcType;
 import org.hibernate.type.spi.TypeConfiguration;
 
+import static org.hibernate.type.SqlTypes.SMALLINT;
+import static org.hibernate.type.SqlTypes.TINYINT;
+
 /**
  * BasicValue.Resolution resolver for cases where no explicit
  * type info was supplied.
@@ -344,19 +346,19 @@ public class InferredBasicValueResolver {
 			TypeConfiguration typeConfiguration) {
 		return ordinalResolution(
 				enumJavaType,
-				integerJavaType( explicitJavaType, typeConfiguration ),
+				ordinalJavaType( explicitJavaType, typeConfiguration ),
-				integerJdbcType( explicitJdbcType, typeConfiguration ),
+				ordinalJdbcType( explicitJdbcType, enumJavaType, typeConfiguration ),
 				typeConfiguration
 		);
 	}
 
-	private static JdbcType integerJdbcType(JdbcType explicitJdbcType, TypeConfiguration typeConfiguration) {
+	private static JdbcType ordinalJdbcType(JdbcType explicitJdbcType, EnumJavaType<?> enumJavaType, TypeConfiguration typeConfiguration) {
 		return explicitJdbcType != null
 				? explicitJdbcType
-				: typeConfiguration.getJdbcTypeRegistry().getDescriptor( SqlTypes.SMALLINT );
+				: typeConfiguration.getJdbcTypeRegistry().getDescriptor( enumJavaType.hasManyValues() ? SMALLINT : TINYINT );
 	}
 
-	private static <N extends Number> JavaType<N> integerJavaType(JavaType<N> explicitJavaType, TypeConfiguration typeConfiguration) {
+	private static <N extends Number> JavaType<N> ordinalJavaType(JavaType<N> explicitJavaType, TypeConfiguration typeConfiguration) {
 		if ( explicitJavaType != null ) {
 			if ( !Integer.class.isAssignableFrom( explicitJavaType.getJavaTypeClass() ) ) {
 				throw new MappingException(

hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java

@@ -1326,7 +1326,6 @@ public abstract class Dialect implements ConversionContext {
 	public boolean equivalentTypes(int typeCode1, int typeCode2) {
 		return typeCode1==typeCode2
 			|| isNumericOrDecimal(typeCode1) && isNumericOrDecimal(typeCode2)
-			|| isSmallOrTinyInt(typeCode1) && isSmallOrTinyInt(typeCode2) //special case for HHH-15288 migration
 //			|| isIntegral(typeCode1) && isIntegral(typeCode2)
 			|| isFloatOrRealOrDouble(typeCode1) && isFloatOrRealOrDouble(typeCode2)
 			|| isVarcharType(typeCode1) && isVarcharType(typeCode2)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/EnumJavaType.java

@@ -6,15 +6,22 @@
  */
 package org.hibernate.type.descriptor.java;
 
-import java.sql.Types;
 import jakarta.persistence.EnumType;
 
-import org.hibernate.type.SqlTypes;
+import org.hibernate.AssertionFailure;
 import org.hibernate.type.descriptor.WrapperOptions;
 import org.hibernate.type.descriptor.jdbc.JdbcType;
 import org.hibernate.type.descriptor.jdbc.JdbcTypeIndicators;
 import org.hibernate.type.descriptor.jdbc.spi.JdbcTypeRegistry;
 
+import static jakarta.persistence.EnumType.ORDINAL;
+import static org.hibernate.type.SqlTypes.CHAR;
+import static org.hibernate.type.SqlTypes.NCHAR;
+import static org.hibernate.type.SqlTypes.NVARCHAR;
+import static org.hibernate.type.SqlTypes.SMALLINT;
+import static org.hibernate.type.SqlTypes.TINYINT;
+import static org.hibernate.type.SqlTypes.VARCHAR;
+
 /**
  * Describes a Java {@code enum} type.
  *
@@ -27,21 +34,27 @@ public class EnumJavaType<T extends Enum<T>> extends AbstractClassJavaType<T> {
 
 	@Override
 	public JdbcType getRecommendedJdbcType(JdbcTypeIndicators context) {
-		JdbcTypeRegistry registry = context.getTypeConfiguration().getJdbcTypeRegistry();
+		final JdbcTypeRegistry registry = context.getTypeConfiguration().getJdbcTypeRegistry();
-		if ( context.getEnumeratedType() != null && context.getEnumeratedType() == EnumType.STRING ) {
+		final EnumType type = context.getEnumeratedType();
-			if ( context.getColumnLength() == 1 ) {
+		switch ( type == null ? ORDINAL : type ) {
+			case ORDINAL:
+				return registry.getDescriptor( hasManyValues() ? SMALLINT : TINYINT );
+			case STRING:
+				if ( context.getColumnLength() == 1 ) {
+					return context.isNationalized()
+							? registry.getDescriptor( NCHAR )
+							: registry.getDescriptor( CHAR );
+				}
 				return context.isNationalized()
-						? registry.getDescriptor( Types.NCHAR )
+						? registry.getDescriptor( NVARCHAR )
-						: registry.getDescriptor( Types.CHAR );
+						: registry.getDescriptor( VARCHAR );
-			}
+			default:
+				throw new AssertionFailure("unknown EnumType");
+		}
+	}
 
-			return context.isNationalized()
+	public boolean hasManyValues() {
-					? registry.getDescriptor( Types.NVARCHAR )
+		return getJavaTypeClass().getEnumConstants().length > 128; // a bit arbitrary, but gives us some headroom
-					: registry.getDescriptor( Types.VARCHAR );
-		}
-		else {
-			return registry.getDescriptor( SqlTypes.SMALLINT );
-		}
 	}
 
 	@Override

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/enumerated/EnumeratedSmokeTest.java

@@ -79,7 +79,7 @@ public class EnumeratedSmokeTest extends BaseUnitTestCase {
 		assertThat( hibernateMappingEnumType.isOrdinal(), is(expectedJpaEnumType==EnumType.ORDINAL) );
 		final int expectedJdbcTypeCode = jdbcRegistry.getDescriptor(
 				expectedJpaEnumType == EnumType.ORDINAL ?
-						Types.SMALLINT :
+						Types.TINYINT :
 						Types.VARCHAR
 		).getJdbcTypeCode();
 		assertThat(

hibernate-core/src/test/java/org/hibernate/orm/test/bootstrap/binding/annotations/basics/EnumResolutionTests.java

@@ -60,7 +60,7 @@ public class EnumResolutionTests {
 
 		verifyEnumResolution(
 				entityBinding.getProperty( "rawEnum" ),
-				Types.SMALLINT,
+				Types.TINYINT,
 				Integer.class,
 				OrdinalEnumValueConverter.class,
 				true
@@ -75,7 +75,7 @@ public class EnumResolutionTests {
 
 		verifyEnumResolution(
 				entityBinding.getProperty( "unspecifiedMappingEnum" ),
-				Types.SMALLINT,
+				Types.TINYINT,
 				Integer.class,
 				OrdinalEnumValueConverter.class,
 				true
@@ -90,7 +90,7 @@ public class EnumResolutionTests {
 
 		verifyEnumResolution(
 				entityBinding.getProperty( "ordinalEnum" ),
-				Types.SMALLINT,
+				Types.TINYINT,
 				Integer.class,
 				OrdinalEnumValueConverter.class,
 				true
@@ -143,7 +143,7 @@ public class EnumResolutionTests {
 
 		verifyEnumResolution(
 				entityBinding.getProperty( "explicitEnum" ),
-				Types.TINYINT,
+				Types.SMALLINT,
 				Integer.class,
 				OrdinalEnumValueConverter.class,
 				true
@@ -222,7 +222,7 @@ public class EnumResolutionTests {
 		private Values namedEnum;
 
 		@Enumerated( ORDINAL )
-		@JdbcTypeCode( Types.TINYINT )
+		@JdbcTypeCode( Types.SMALLINT )
 		private Values explicitEnum;
 	}
 

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/SmokeTests.java

@@ -104,7 +104,7 @@ public class SmokeTests {
 
 			assertThat(
 					jdbcTypeRegistry.getDescriptor( valueConverter.getJdbcTypeCode() ),
-					is( jdbcTypeRegistry.getDescriptor( Types.SMALLINT ) )
+					is( jdbcTypeRegistry.getDescriptor( Types.TINYINT ) )
 			);
 		}
 

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

@@ -191,7 +191,7 @@ public class SmokeTests {
 					assertThat( enumConverter.getRelationalJavaType().getJavaTypeClass(), AssignableMatcher.assignableTo( Integer.class ) );
 					assertThat(
 							basicType.getJdbcType(),
-							is( jdbcTypeRegistry.getDescriptor( Types.SMALLINT ) )
+							is( jdbcTypeRegistry.getDescriptor( Types.TINYINT ) )
 					);
 
 

hibernate-core/src/test/java/org/hibernate/orm/test/type/EnumArrayTest.java

@@ -7,7 +7,10 @@
 package org.hibernate.orm.test.type;
 
 import org.hibernate.dialect.AbstractHANADialect;
+import org.hibernate.dialect.DB2Dialect;
+import org.hibernate.dialect.DerbyDialect;
 import org.hibernate.dialect.HSQLDialect;
+import org.hibernate.dialect.MySQLDialect;
 import org.hibernate.dialect.OracleDialect;
 import org.hibernate.dialect.SybaseASEDialect;
 
@@ -24,8 +27,6 @@ import jakarta.persistence.Query;
 import jakarta.persistence.Table;
 import jakarta.persistence.TypedQuery;
 
-import org.hibernate.testing.DialectChecks;
-import org.hibernate.testing.RequiresDialectFeature;
 import org.hibernate.testing.SkipForDialect;
 import org.hibernate.testing.junit4.BaseNonConfigCoreFunctionalTestCase;
 import org.junit.Test;
@@ -113,6 +114,9 @@ public class EnumArrayTest extends BaseNonConfigCoreFunctionalTestCase {
 	@Test
 	@SkipForDialect( value = HSQLDialect.class, comment = "HSQL does not like plain parameters in the distinct from predicate")
 	@SkipForDialect( value = OracleDialect.class, comment = "Oracle requires a special function to compare XML")
+	@SkipForDialect( value = MySQLDialect.class )
+	@SkipForDialect( value = DerbyDialect.class )
+	@SkipForDialect( value = DB2Dialect.class )
 	public void testNativeQuery() {
 		inSession( em -> {
 			final String op = em.getJdbcServices().getDialect().supportsDistinctFromPredicate() ? "IS NOT DISTINCT FROM" : "=";