From 5aa6433972b2b0980bcb9a658f28a72e426453f8 Mon Sep 17 00:00:00 2001
From: Teemu Suo-Anttila <tsuoanttila@users.noreply.github.com>
Date: Mon, 19 Mar 2018 18:57:26 +0200
Subject: [PATCH] Add missing null check to Binding (#10726)

* Add missing null check to Binding
---
 .../src/main/java/com/vaadin/data/Binder.java |  8 +++++---
 .../test/java/com/vaadin/data/BinderTest.java | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/server/src/main/java/com/vaadin/data/Binder.java b/server/src/main/java/com/vaadin/data/Binder.java
index 406784fda4..769ca74bed 100644
--- a/server/src/main/java/com/vaadin/data/Binder.java
+++ b/server/src/main/java/com/vaadin/data/Binder.java
@@ -1139,9 +1139,11 @@ public class Binder<BEAN> implements Serializable {
          */
         private void handleFieldValueChange(
                 ValueChangeEvent<FIELDVALUE> event) {
-            // Inform binder of changes; if setBean: writeIfValid
-            getBinder().handleFieldValueChange(this, event);
-            getBinder().fireValueChangeEvent(event);
+            if (binder != null) {
+                // Inform binder of changes; if setBean: writeIfValid
+                getBinder().handleFieldValueChange(this, event);
+                getBinder().fireValueChangeEvent(event);
+            }
         }
 
         /**
diff --git a/server/src/test/java/com/vaadin/data/BinderTest.java b/server/src/test/java/com/vaadin/data/BinderTest.java
index 5988061cd5..abbbe541ae 100644
--- a/server/src/test/java/com/vaadin/data/BinderTest.java
+++ b/server/src/test/java/com/vaadin/data/BinderTest.java
@@ -811,6 +811,25 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
                 String.valueOf(item.getAge()), ageField.getValue());
     }
 
+    @Test
+    public void remove_binding_fromFieldValueChangeListener() {
+        // Add listener before bind to make sure it will be executed first.
+        nameField.addValueChangeListener(e -> {
+            if (e.getValue() == "REMOVE") {
+                binder.removeBinding(nameField);
+            }
+        });
+
+        binder.bind(nameField, Person::getFirstName, Person::setFirstName);
+
+        binder.setBean(item);
+
+        nameField.setValue("REMOVE");
+
+        // Removed binding should not update bean.
+        assertNotEquals("REMOVE", item.getFirstName());
+    }
+
     @Test
     public void beanvalidation_two_fields_not_equal() {
         TextField lastNameField = new TextField();
-- 
2.39.5