version reset should not be affected by the id being assigned or generated

improve javadoc for this stuff

Signed-off-by: Gavin King <gavin@hibernate.org>

hibernate-core/src/main/java/org/hibernate/boot/spi/SessionFactoryOptions.java

@@ -131,6 +131,11 @@ public interface SessionFactoryOptions extends QueryEngineOptions {
 
 	BaselineSessionEventsListenerBuilder getBaselineSessionEventsListenerBuilder();
 
+	/**
+	 * Should generated identifiers be reset after entity removal?
+	 *
+	 * @see org.hibernate.cfg.AvailableSettings#USE_IDENTIFIER_ROLLBACK
+	 */
 	boolean isIdentifierRollbackEnabled();
 
 	boolean isCheckNullability();

hibernate-core/src/main/java/org/hibernate/cfg/AvailableSettings.java

@@ -170,6 +170,7 @@ public interface AvailableSettings
 	/**
 	 * When enabled, specifies that the generated identifier of an entity is unset
 	 * when the entity is {@linkplain org.hibernate.Session#remove(Object) deleted}.
+	 * If the entity is versioned, the version is also reset to its default value.
 	 *
 	 * @settingDefault {@code false} - generated identifiers are not unset
 	 *

hibernate-core/src/main/java/org/hibernate/engine/spi/VersionValue.java

@@ -80,8 +80,8 @@ public class VersionValue implements UnsavedValueStrategy {
 			if ( version == null ) {
 				return Boolean.TRUE;
 			}
-			if ( version instanceof Number ) {
-				return ((Number) version).longValue() < 0L;
+			if ( version instanceof Number number ) {
+				return number.longValue() < 0L;
 			}
 			throw new MappingException( "unsaved-value NEGATIVE may only be used with short, int and long types" );
 		}

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

@@ -4359,14 +4359,11 @@ public abstract class AbstractEntityPersister
 			Object currentId,
 			Object currentVersion,
 			SharedSessionContractImplementor session) {
-		if ( entityMetamodel.getIdentifierProperty().getGenerator().allowAssignedIdentifiers() ) {
-			return;
-		}
-
+		if ( !getGenerator().allowAssignedIdentifiers() ) {
 			// reset the identifier
 			final Object defaultIdentifier = identifierMapping.getUnsavedStrategy().getDefaultValue( currentId );
 			setIdentifier( entity, defaultIdentifier, session );
-
+		}
 		// reset the version
 		if ( versionMapping != null ) {
 			final Object defaultVersion = versionMapping.getUnsavedStrategy().getDefaultValue( currentVersion );

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

@@ -1195,6 +1195,9 @@ public interface EntityPersister extends EntityMappingType, EntityMutationTarget
 	/**
 	 * Set the identifier and version of the given instance back to its "unsaved"
 	 * value, that is, the value it had before it was made persistent.
+	 *
+	 * @see org.hibernate.cfg.AvailableSettings#USE_IDENTIFIER_ROLLBACK
+	 * @see org.hibernate.boot.spi.SessionFactoryOptions#isIdentifierRollbackEnabled
 	 */
 	void resetIdentifier(Object entity, Object currentId, Object currentVersion, SharedSessionContractImplementor session);