HHH-16812 Test reproducing the issue

It seems that when trying to call the Smell.setCheese()setter and when
the entity is an uninitialized Food proxy there’s a ClassCastException
(maybe the proxy should be narrowed to the actual class of the entity)
and then it tries to build an exception but to do that it needs to
initialize the entity and that fails again with the same problem.
Building the exception fails because PropertySetterAccessException tries
to call the toString method of the uninitialized proxy.

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

@@ -0,0 +1,141 @@
+package org.hibernate.orm.test.embeddable;
+
+import jakarta.persistence.*;
+import org.hibernate.Hibernate;
+import org.hibernate.annotations.*;
+import org.hibernate.engine.spi.SessionImplementor;
+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.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * @author gtoison
+ *
+ */
+@SessionFactory
+@DomainModel(annotatedClasses = {
+		EmbeddableWithParentWithInheritanceTest.Food.class,
+		EmbeddableWithParentWithInheritanceTest.Cheese.class,
+		EmbeddableWithParentWithInheritanceTest.Roquefort.class,
+		EmbeddableWithParentWithInheritanceTest.Smell.class})
+public class EmbeddableWithParentWithInheritanceTest {
+
+
+	private static final int COUNT = 4;
+
+	@Test public void test(SessionFactoryScope scope) {
+		Long savedId = scope.fromSession(s -> {
+			s.getSession().beginTransaction();
+
+			Roquefort cheese = new Roquefort();
+			Smell smell = new Smell();
+
+			cheese.setSmell(smell);
+			smell.setCheese(cheese);
+			smell.setName("blue cheese");
+
+			s.persist(cheese);
+			
+			s.getSession().getTransaction().commit();
+
+			return cheese.id;
+		});
+
+		scope.inSession(s -> {
+			Food food = s.getReference(Food.class, savedId);
+			assertFalse(Hibernate.isInitialized(food));
+			assertEquals("Smells like blue cheese", food.describe());
+		});
+	}
+
+	@Entity
+	@Cacheable
+	@BatchSize(size = 512)
+	@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
+	@DiscriminatorColumn(discriminatorType = DiscriminatorType.STRING, name = "type")
+	@DiscriminatorValue(value = "FOOD")
+	public static class Food {
+		Long id;
+
+		public Food() {
+		}
+
+		public String describe() {
+			return "Good food";
+		}
+
+		@Id
+		@GeneratedValue(strategy = GenerationType.IDENTITY)
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+	}
+
+	@Entity
+	@DiscriminatorValue("VEGETABLE")
+	public static class Vegetable extends Food {
+
+	}
+
+	@Entity
+	@DiscriminatorValue("CHEESE")
+	public static class Cheese extends Food {
+	}
+
+	@Entity
+	@DiscriminatorValue("ROQUEFORT")
+	public static class Roquefort extends Cheese {
+		Smell smell;
+
+		public Roquefort() {
+		}
+
+		@Override
+		public String describe() {
+			return "Smells like " + getSmell().getName();
+		}
+
+		@Embedded
+		public Smell getSmell() {
+			return smell;
+		}
+
+		public void setSmell(Smell smell) {
+			this.smell = smell;
+		}
+	}
+
+	@Embeddable
+	public static class Smell {
+		Cheese cheese;
+
+		String name;
+
+		@Parent
+		public Cheese getCheese() {
+			return cheese;
+		}
+
+		public void setCheese(Cheese cheese) {
+			this.cheese = cheese;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+	}
+}