Add assertion to ensure copied shadow nodes are of the same type as the original

Reviewed By: mdvacca

Differential Revision: D7664638

fbshipit-source-id: e1b7acbafd8a8fd9d6301d8afbb3e5959dc15b7a

Author: ayc1

ReactAndroid/src/main/java/com/facebook/react/uimanager/ReactShadowNodeImpl.java

@@ -166,6 +166,9 @@ protected ReactShadowNodeImpl copy() {
   @Override
   public ReactShadowNodeImpl mutableCopy() {
     ReactShadowNodeImpl copy = copy();
+    Assertions.assertCondition(
+        getClass() == copy.getClass(),
+        "Copied shadow node must use the same class");
     if (mYogaNode != null) {
       copy.mYogaNode = mYogaNode.clone();
       copy.mYogaNode.setData(copy);
@@ -182,6 +185,9 @@ public ReactShadowNodeImpl mutableCopy() {
   @Override
   public ReactShadowNodeImpl mutableCopyWithNewChildren() {
     ReactShadowNodeImpl copy = copy();
+    Assertions.assertCondition(
+        getClass() == copy.getClass(),
+        "Copied shadow node must use the same class");
     if (mYogaNode != null) {
       copy.mYogaNode = mYogaNode.cloneWithNewChildren();
       copy.mYogaNode.setData(copy);

ReactAndroid/src/test/java/com/facebook/react/fabric/ReactShadowNodeTest.java

@@ -0,0 +1,20 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+package com.facebook.react.fabric;
+
+import com.facebook.react.uimanager.ReactShadowNodeImpl;
+import com.facebook.testing.robolectric.v3.WithTestDefaultsRunner;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Tests {@link ReactShadowNode} */
+@RunWith(WithTestDefaultsRunner.class)
+public class ReactShadowNodeTest {
+
+  @Test(expected = AssertionError.class)
+  public void testClonedInstance() {
+    TestReactShadowNode node = new TestReactShadowNode();
+    node.mutableCopy();
+  }
+
+  private static class TestReactShadowNode extends ReactShadowNodeImpl {}
+}