HHH-15271 Don't initialize lazy associations via merge

Author: dreab8

hibernate-core/src/main/java/org/hibernate/Session.java

@@ -660,6 +660,22 @@ public interface Session extends SharedSessionContract, EntityManager {
 	 */
 	<T> T merge(String entityName, T object);
 
+	/**
+	 * Copy the state of the given object onto the persistent object with the same
+	 * identifier. If there is no persistent instance currently associated with
+	 * the session, it will be loaded. Return the persistent instance. If the
+	 * given instance is unsaved, save a copy and return it as a newly persistent
+	 * instance. The given instance does not become associated with the session.
+	 * This operation cascades to associated instances if the association is mapped
+	 * with {@link jakarta.persistence.CascadeType#MERGE}.
+	 *
+	 * @param object a detached instance with state to be copied
+	 * @param loadGraph entity graph interpreted as a load graph
+	 *
+	 * @return an updated persistent instance
+	 */
+	<T> T merge( T object, EntityGraph<?> loadGraph);
+
 	/**
 	 * Make a transient instance persistent and mark it for later insertion in the
 	 * database. This operation cascades to associated instances if the association

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

@@ -825,6 +825,11 @@ public <T> T merge(String entityName, T object) {
 		return delegate.merge( entityName, object );
 	}
 
+	@Override
+	public <T> T merge(T object, EntityGraph<?> loadGraph) {
+		return delegate.merge( object, loadGraph );
+	}
+
 	@Override
 	public void persist(Object object) {
 		delegate.persist( object );

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

@@ -210,6 +210,11 @@ public <T> T merge(String entityName, T object) {
 		return this.lazySession.get().merge( entityName, object );
 	}
 
+	@Override
+	public <T> T merge(T object, EntityGraph<?> loadGraph) {
+		return this.lazySession.get().merge( object, loadGraph );
+	}
+
 	@Override
 	public void persist(Object object) {
 		this.lazySession.get().persist( object );

hibernate-core/src/main/java/org/hibernate/internal/SessionImpl.java

@@ -803,6 +803,19 @@ public <T> T merge(String entityName, T object) {
 		return (T) fireMerge( new MergeEvent( entityName, object, this ) );
 	}
 
+	@Override
+	public <T> T merge(T object, EntityGraph<?> loadGraph) {
+		EffectiveEntityGraph effectiveEntityGraph = loadQueryInfluencers.getEffectiveEntityGraph();
+		try {
+			effectiveEntityGraph
+					.applyGraph( (RootGraphImplementor<?>) loadGraph, GraphSemantic.LOAD );
+			return merge( object );
+		}
+		finally {
+			effectiveEntityGraph.clear();
+		}
+	}
+
 	@Override @SuppressWarnings("unchecked")
 	public <T> T merge(T object) {
 		checkOpen();