HHH-17925 Allow mapping join column on single attribute of composite id

Author: mbellade

hibernate-core/src/main/java/org/hibernate/engine/internal/AbstractEntityEntry.java

@@ -27,6 +27,7 @@
 import org.hibernate.engine.spi.SessionImplementor;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.engine.spi.Status;
+import org.hibernate.metamodel.mapping.AttributeMapping;
 import org.hibernate.persister.entity.EntityPersister;
 import org.hibernate.type.TypeHelper;
 
@@ -324,13 +325,16 @@ else if ( earlyInsert ) {
 
 	@Override
 	public Object getLoadedValue(String propertyName) {
-		return loadedState == null || propertyName == null
-				? null
-				: loadedState[ propertyIndex( propertyName ) ];
+		if ( loadedState == null || propertyName == null ) {
+			return null;
+		}
+		final int index = propertyIndex( propertyName );
+		return index < 0 ? null : loadedState[index];
 	}
 
 	private int propertyIndex(String propertyName) {
-		return persister.findAttributeMapping( propertyName ).getStateArrayPosition();
+		final AttributeMapping attributeMapping = persister.findAttributeMapping( propertyName );
+		return attributeMapping != null ? attributeMapping.getStateArrayPosition() : -1;
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/MappingModelCreationHelper.java

@@ -784,7 +784,7 @@ private static void interpretPluralAttributeMappingKeyDescriptor(
 			fkTargetPart = collectionDescriptor.getOwnerEntityPersister().getIdentifierMapping();
 		}
 		else {
-			fkTargetPart = declaringType.findContainingEntityMapping().findAttributeMapping( lhsPropertyName );
+			fkTargetPart = declaringType.findContainingEntityMapping().findSubPart( lhsPropertyName );
 		}
 
 		if ( keyType instanceof BasicType ) {

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

@@ -1270,9 +1270,12 @@ private static List<UniqueKeyEntry> initUniqueKeyEntries(final AbstractEntityPer
 				final AssociationType associationType = (AssociationType) propertyType;
 				final String ukName = associationType.getLHSPropertyName();
 				if ( ukName != null ) {
-					final int index = aep.findAttributeMapping( ukName ).getStateArrayPosition();
-					final Type type = aep.getPropertyTypes()[index];
-					uniqueKeys.add( new UniqueKeyEntry( ukName, index, type ) );
+					final AttributeMapping attributeMapping = aep.findAttributeMapping( ukName );
+					if ( attributeMapping != null ) {
+						final int index = attributeMapping.getStateArrayPosition();
+						final Type type = aep.getPropertyTypes()[index];
+						uniqueKeys.add( new UniqueKeyEntry( ukName, index, type ) );
+					}
 				}
 			}
 		}
@@ -4542,10 +4545,10 @@ public Object getPropertyValue(Object object, String propertyName) {
 			}
 		}
 		else if ( identifierMapping instanceof NonAggregatedIdentifierMapping ) {
-			final EmbeddedAttributeMapping embeddedAttributeMapping =
-					(EmbeddedAttributeMapping) findAttributeMapping( NavigableRole.IDENTIFIER_MAPPER_PROPERTY );
-			final AttributeMapping mapping = embeddedAttributeMapping == null ? null
-					: embeddedAttributeMapping.getMappedType().findAttributeMapping( basePropertyName );
+			final AttributeMapping mapping = ( (NonAggregatedIdentifierMapping) identifierMapping ).findSubPart(
+					propertyName,
+					null
+			).asAttributeMapping();
 			if ( mapping != null ) {
 				baseValue = mapping.getAttributeMetadata().getPropertyAccess().getGetter().get( object );
 				if ( dotIndex != -1 ) {

hibernate-core/src/main/java/org/hibernate/type/CollectionType.java

@@ -369,7 +369,7 @@ public ForeignKeyDirection getForeignKeyDirection() {
 	public Object getKeyOfOwner(Object owner, SharedSessionContractImplementor session) {
 		final PersistenceContext pc = session.getPersistenceContextInternal();
 
-		EntityEntry entityEntry = pc.getEntry( owner );
+		final EntityEntry entityEntry = pc.getEntry( owner );
 		if ( entityEntry == null ) {
 			// This just handles a particular case of component
 			// projection, perhaps get rid of it and throw an exception
@@ -385,9 +385,10 @@ public Object getKeyOfOwner(Object owner, SharedSessionContractImplementor sessi
 			// later in the mapping document) - now, we could try and use e.getStatus()
 			// to decide to semiResolve(), trouble is that initializeEntity() reuses
 			// the same array for resolved and hydrated values
-			Object id = entityEntry.getLoadedState() != null
-					? entityEntry.getLoadedValue( foreignKeyPropertyName )
-					: entityEntry.getPersister().getPropertyValue( owner, foreignKeyPropertyName );
+			final Object loadedValue = entityEntry.getLoadedValue( foreignKeyPropertyName );
+			final Object id = loadedValue == null ?
+					entityEntry.getPersister().getPropertyValue( owner, foreignKeyPropertyName ) :
+					loadedValue;
 
 			// NOTE VERY HACKISH WORKAROUND!!
 			// TODO: Fix this so it will work for non-POJO entity mode