From f2b31bac2bc521945c8887b8a8c16df2d5845ac1 Mon Sep 17 00:00:00 2001
From: Teemu Suo-Anttila <teemusa@vaadin.com>
Date: Mon, 8 Feb 2016 16:42:00 +0200
Subject: [PATCH] Fix removing extension from a connector that is not its
 parent (#19569)

Change-Id: I0201c2dc94cd50d09931d54bb9e18893e6737d9c
---
 .../server/AbstractClientConnector.java       |  5 +++
 .../vaadin/tests/server/ExtensionTest.java    | 40 +++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 server/tests/src/com/vaadin/tests/server/ExtensionTest.java

diff --git a/server/src/com/vaadin/server/AbstractClientConnector.java b/server/src/com/vaadin/server/AbstractClientConnector.java
index fa2b741ddd..c624663d50 100644
--- a/server/src/com/vaadin/server/AbstractClientConnector.java
+++ b/server/src/com/vaadin/server/AbstractClientConnector.java
@@ -589,6 +589,11 @@ public abstract class AbstractClientConnector implements ClientConnector,
 
     @Override
     public void removeExtension(Extension extension) {
+        if (extension.getParent() != this) {
+            throw new IllegalArgumentException(
+                    "This connector is not the parent for given extension");
+        }
+
         extension.setParent(null);
         extensions.remove(extension);
         markAsDirty();
diff --git a/server/tests/src/com/vaadin/tests/server/ExtensionTest.java b/server/tests/src/com/vaadin/tests/server/ExtensionTest.java
new file mode 100644
index 0000000000..8f8e8dcb59
--- /dev/null
+++ b/server/tests/src/com/vaadin/tests/server/ExtensionTest.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2000-2014 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.server;
+
+import org.junit.Test;
+
+import com.vaadin.server.AbstractClientConnector;
+import com.vaadin.server.AbstractExtension;
+import com.vaadin.ui.Label;
+import com.vaadin.ui.TextField;
+
+public class ExtensionTest {
+
+    public static class DummyExtension extends AbstractExtension {
+        public DummyExtension(AbstractClientConnector target) {
+            super(target);
+        }
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testRemoveExtensionFromWrongConnector() {
+        Label l = new Label();
+        TextField t = new TextField();
+        t.removeExtension(new DummyExtension(l));
+    }
+
+}
-- 
2.39.5