HHH-19684 Fix ClassCastException when using enums as part of a composite type

hibernate-core/src/main/java/org/hibernate/dialect/type/AbstractPostgreSQLStructJdbcType.java

@@ -1232,7 +1232,7 @@ private void serializeConvertedBasicTo(
 			case SqlTypes.ENUM:
 			case SqlTypes.NAMED_ENUM:
 				appender.quoteStart();
-				appender.append( (String) subValue );
+				appender.append( subValue.toString() );
 				appender.quoteEnd();
 				break;
 			case SqlTypes.DATE:

hibernate-core/src/test/java/org/hibernate/orm/test/component/StructComponentEnumTest.java

@@ -0,0 +1,111 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.component;
+
+
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
+import org.hibernate.annotations.JdbcTypeCode;
+import org.hibernate.annotations.Struct;
+
+import org.hibernate.dialect.PostgreSQLDialect;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.RequiresDialect;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.hibernate.type.SqlTypes;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Embeddable;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+
+@DomainModel(
+		annotatedClasses = {
+				StructComponentEnumTest.Book.class,
+				StructComponentEnumTest.Publisher.class
+		}
+)
+@SessionFactory
+@RequiresDialect(PostgreSQLDialect.class)
+public class StructComponentEnumTest {
+
+	@Test
+	public void save(SessionFactoryScope scope){
+		scope.inTransaction(
+				session -> {
+
+					Book book = new Book();
+					book.title = "Hibernate";
+					book.author = "Steve";
+					book.publisher = new Publisher( "penguin", PublisherType.TRADITIONAL );
+
+					session.persist( book );
+				}
+		);
+	}
+
+	@AfterEach
+	public void tearDown(SessionFactoryScope scope){
+		scope.getSessionFactory().getSchemaManager().truncate();
+	}
+
+	@Entity(name = "Book")
+	public static class Book {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		private String title;
+
+		private String author;
+
+		private Publisher publisher;
+	}
+
+	@Embeddable
+	@Struct( name = "publisher_type")
+	public static class Publisher {
+
+		private String name;
+
+		@Enumerated(EnumType.STRING)
+		@JdbcTypeCode(SqlTypes.NAMED_ENUM)
+		private PublisherType type;
+
+		public Publisher(String name, PublisherType type) {
+			this.name = name;
+			this.type = type;
+		}
+
+		public Publisher() {
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public PublisherType getType() {
+			return type;
+		}
+
+		public void setType(PublisherType type) {
+			this.type = type;
+		}
+	}
+
+	public enum PublisherType {
+		TRADITIONAL, SELF_PUBLISHED, PRINT_ON_DEMAND
+	}
+
+
+}