Failure merging a referenced entity

hibernate-core/src/test/java/org/hibernate/orm/test/embeddable/MergeWithReferenceTest.java

@@ -0,0 +1,117 @@
+package org.hibernate.orm.test.embeddable;
+
+import java.io.Serializable;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+
+import org.hibernate.annotations.Fetch;
+import org.hibernate.annotations.FetchMode;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Column;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import org.assertj.core.api.Assertions;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(annotatedClasses = {
+		MergeWithReferenceTest.Foo.class,
+		MergeWithReferenceTest.Bar.class
+})
+@SessionFactory
+public class MergeWithReferenceTest {
+
+	@Test
+	public void testMergeReference(SessionFactoryScope scope) {
+		Bar bar = new Bar( "unique3" );
+		scope.inTransaction( session -> {
+			session.persist( bar );
+		} );
+		scope.inTransaction( session -> {
+			Foo merged = session.merge( new Foo( session.getReference( Bar.class, bar.getId() ) ) );
+			Assertions.assertThat( merged.getBar().getKey() ).isEqualTo( bar.getKey() );
+		} );
+	}
+
+	@Entity(name = "Foo")
+	static class Foo {
+		Foo(Bar bar) {
+			this.bar = bar;
+		}
+
+		Foo() {
+		}
+
+		@Id
+		@GeneratedValue
+		long id;
+		@ManyToOne(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
+		@Fetch(FetchMode.JOIN)
+		@JoinColumn(name = "bar_key", referencedColumnName = "nat_key")
+		Bar bar;
+
+		public long getId() {
+			return id;
+		}
+
+		public void setId(long id) {
+			this.id = id;
+		}
+
+		public Bar getBar() {
+			return bar;
+		}
+
+		public void setBar(Bar bar) {
+			this.bar = bar;
+		}
+	}
+
+	@Entity(name = "Bar")
+	static class Bar implements Serializable {
+		Bar(String key) {
+			this.key = key;
+		}
+
+		Bar() {
+		}
+
+		@Id
+		@GeneratedValue
+		long id;
+		@Column(name = "nat_key", unique = true)
+		String key;
+
+		public long getId() {
+			return id;
+		}
+
+		public void setId(long id) {
+			this.id = id;
+		}
+
+		public String getKey() {
+			return key;
+		}
+
+		public void setKey(String key) {
+			this.key = key;
+		}
+	}
+}