Regression test for issue #16860 resolved by HHH-14575

integration-tests/jpa-h2/src/main/java/io/quarkus/it/jpa/h2/basicproxy/AbstractEntity.java

@@ -0,0 +1,43 @@
+package io.quarkus.it.jpa.h2.basicproxy;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+import javax.persistence.Column;
+import javax.persistence.DiscriminatorColumn;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "ENTITY")
+@DiscriminatorColumn(name = "TYPE")
+public abstract class AbstractEntity implements Serializable {
+
+    public AbstractEntity() {
+        // nop
+    }
+
+    @Id
+    @Column(name = "TYPE", insertable = false, updatable = false)
+    public String type;
+
+    @Id
+    @Column(name = "ID")
+    public String id;
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        AbstractEntity that = (AbstractEntity) o;
+        return Objects.equals(type, that.type) && Objects.equals(id, that.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(type, id);
+    }
+}

integration-tests/jpa-h2/src/main/java/io/quarkus/it/jpa/h2/basicproxy/BasicProxyTestEndpoint.java

@@ -0,0 +1,41 @@
+package io.quarkus.it.jpa.h2.basicproxy;
+
+import java.io.IOException;
+import java.util.List;
+
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.event.Observes;
+import javax.inject.Inject;
+import javax.persistence.EntityManager;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.transaction.Transactional;
+
+import io.quarkus.runtime.StartupEvent;
+
+@ApplicationScoped
+@WebServlet(urlPatterns = "/jpa-h2/testbasicproxy")
+public class BasicProxyTestEndpoint extends HttpServlet {
+
+    @Inject
+    EntityManager entityManager;
+
+    @Transactional
+    public void setup(@Observes StartupEvent startupEvent) {
+        ConcreteEntity entity = new ConcreteEntity();
+        entity.id = "1";
+        entity.type = "Concrete";
+        entityManager.persist(entity);
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        final List list = entityManager.createQuery("from ConcreteEntity").getResultList();
+        if (list.size() != 1) {
+            throw new RuntimeException("Expected 1 result, got " + list.size());
+        }
+        resp.getWriter().write("OK");
+    }
+}

integration-tests/jpa-h2/src/main/java/io/quarkus/it/jpa/h2/basicproxy/ConcreteEntity.java

@@ -0,0 +1,14 @@
+package io.quarkus.it.jpa.h2.basicproxy;
+
+import javax.persistence.DiscriminatorValue;
+import javax.persistence.Entity;
+
+@Entity
+@DiscriminatorValue("Concrete")
+public class ConcreteEntity extends AbstractEntity {
+
+    public ConcreteEntity() {
+        super();
+    }
+
+}

integration-tests/jpa-h2/src/test/java/io/quarkus/it/jpa/h2/JPAFunctionalityTest.java

@@ -25,4 +25,9 @@ public void testHibernateEnhancedProxies() throws Exception {
         RestAssured.when().get("/jpa-h2/testproxy").then().body(is("OK"));
     }
 
+    @Test
+    public void testHibernateEnhancedBasicProxies() throws Exception {
+        RestAssured.when().get("/jpa-h2/testbasicproxy").then().body(is("OK"));
+    }
+
 }