#2404 - Initializing @OneToMany with mutableListOf() in Kotlin results in ClassCastException

ebean-test/src/test/java/org/tests/o2m/TestOneToManyEnhancement.java

@@ -0,0 +1,29 @@
+package org.tests.o2m;
+
+import io.ebean.BaseTestCase;
+import io.ebean.common.BeanList;
+import org.junit.jupiter.api.Test;
+import org.tests.model.json.EBasicJsonMap;
+import org.tests.o2m.lazy.OmlBaz;
+import org.tests.o2m.lazy.OmlFoo;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class TestOneToManyEnhancement extends BaseTestCase {
+
+  @Test
+  void test_when_constructorAddsEntry() {
+    OmlFoo foo = new OmlFoo(new OmlBaz());
+
+    assertThat(foo.getBazList()).isInstanceOf(BeanList.class);
+    assertThat(foo.getBazList()).isNotEmpty();
+  }
+
+  @Test
+  void test_commonCase() {
+    EBasicJsonMap bean = new EBasicJsonMap();
+
+    assertThat(bean.getDetails()).isInstanceOf(BeanList.class);
+    assertThat(bean.getDetails()).isEmpty();
+  }
+}

ebean-test/src/test/java/org/tests/o2m/lazy/OmlFoo.java

@@ -15,7 +15,12 @@ public class OmlFoo {
   private OmlBar bar;
 
   @OneToMany(mappedBy = "foo", cascade = CascadeType.ALL)
-  private List<OmlBaz> bazList = new ArrayList<OmlBaz>();
+  private List<OmlBaz> bazList = new ArrayList<>();
+
+  public OmlFoo(OmlBaz baz) {
+    bazList.add(baz);
+    baz.setFoo(this);
+  }
 
   public Long getId() {
     return id;

ebean-test/src/test/java/org/tests/o2m/lazy/TestLazyManyViaPath.java

@@ -13,11 +13,9 @@ public class TestLazyManyViaPath extends BaseTestCase {
 
   @Test
   public void test() {
-
     OmlBar bar = new OmlBar();
     List<OmlFoo> fooList = new ArrayList<>();
     fooList.add(createNewFooWithBar(bar));
-
     bar.setFooList(fooList);
 
     DB.save(bar);
@@ -30,26 +28,24 @@ public class TestLazyManyViaPath extends BaseTestCase {
 
     // This works
     List<OmlFoo> foosList = fooFromDb.getBar().getFooList();
-    assertThat(fooList.size()).isEqualTo(1);
+    assertThat(foosList).hasSize(1);
+    assertThat(fooList).hasSize(1);
 
     OmlBaz bazFromDb = DB
       .find(OmlBaz.class)
       .where()
       .eq("id", bar.getFooList().get(0).getBazList().get(0).getId())
       .findOne();
+    assert bazFromDb != null;
 
     // This does not work and gives the exception
     List<OmlFoo> foosList1 = bazFromDb.getFoo().getBar().getFooList();
     assertThat(foosList1.size()).isEqualTo(1);
-
   }
 
   private static OmlFoo createNewFooWithBar(OmlBar bar) {
-    OmlFoo foo = new OmlFoo();
+    OmlFoo foo = new OmlFoo(new OmlBaz());
     foo.setBar(bar);
-    OmlBaz baz = new OmlBaz();
-    baz.setFoo(foo);
-    foo.getBazList().add(baz);
     return foo;
   }
 

tests/test-kotlin/src/test/kotlin/io/ebean/test/kotlin/OneToManyEnhancementTest.kt

@@ -0,0 +1,18 @@
+package io.ebean.test.kotlin
+
+import io.ebean.common.BeanList
+import org.assertj.core.api.Assertions.assertThat
+import org.example.order.Customer
+import org.example.order.Order
+import org.junit.jupiter.api.Test
+
+class OneToManyEnhancementTest {
+
+  @Test
+  fun `o2m is BeanCollection`() {
+    val customer = Customer("foo")
+    val order = Order(customer)
+
+    assertThat(order.items).isInstanceOf(BeanList::class.java)
+  }
+}