Hhh 19079 backport 6.6

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

@@ -440,7 +440,7 @@ public Object[] getPropertyValues(Object component, SharedSessionContractImpleme
 	@Override
 	public Object[] getPropertyValues(Object component) {
 		if (component == null) {
-			return new Object[propertySpan];
+			return new Object[propertySpan + discriminatorColumnSpan];
 		}
 		else if ( component instanceof Object[] ) {
 			// A few calls to hashCode pass the property values already in an

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/EmbeddableInheritanceReplaceTest.java

@@ -0,0 +1,119 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.orm.test.inheritance;
+
+import jakarta.persistence.*;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Test;
+
+@DomainModel(annotatedClasses = {
+		EmbeddableInheritanceReplaceTest.Emb.class,
+		EmbeddableInheritanceReplaceTest.Base.class,
+		EmbeddableInheritanceReplaceTest.Next.class,
+		EmbeddableInheritanceReplaceTest.Ent.class
+})
+@SessionFactory
+@JiraKey("HHH-19079")
+public class EmbeddableInheritanceReplaceTest {
+
+	@Test
+	void merge(SessionFactoryScope scope) {
+		scope.inTransaction(session -> {
+			final var history = new Ent();
+			history.setBase(new Emb(42, "Hello, World!"));
+
+			session.merge(history);
+		});
+	}
+
+	@Embeddable
+	@DiscriminatorValue("E")
+	public static final class Emb extends Next {
+
+		Emb() {
+		}
+
+		public Emb(int num, String str) {
+			super(num, str);
+		}
+	}
+
+	@Embeddable
+	@DiscriminatorColumn(discriminatorType = DiscriminatorType.CHAR)
+	@DiscriminatorValue("b")
+	public static class Base {
+
+		protected int num;
+
+		protected Base() {
+		}
+
+		public Base(int num, String str) {
+			this.num = num;
+		}
+
+		public int getNum() {
+			return num;
+		}
+
+		public void setNum(int num) {
+			this.num = num;
+		}
+	}
+
+	@Embeddable
+	@DiscriminatorValue("n")
+	public static class Next extends Base {
+
+		private String str;
+
+		public Next(int num, String str) {
+			super(num, str);
+			this.str = str;
+		}
+
+		public Next() {
+		}
+	}
+
+	@Entity(name = "Ent")
+	public static class Ent {
+
+		@Id
+		@GeneratedValue
+		private Integer id;
+
+		@Embedded
+		private Base base;
+
+		public Ent() {
+		}
+
+		public Ent(final Integer id) {
+			this.id = id;
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public void setId(Integer id) {
+			this.id = id;
+		}
+
+		public Base getBase() {
+			return base;
+		}
+
+		public void setBase(Base base) {
+			this.base = base;
+		}
+	}
+}