fix: avoid ConcurrentModificationException in Binder (#12458)

1 files changed, 23 insertions, 0 deletions

diff --git a/server/src/test/java/com/vaadin/data/BinderTest.java b/server/src/test/java/com/vaadin/data/BinderTest.java
index 9f20f0b246..999142a440 100644
--- a/server/src/test/java/com/vaadin/data/BinderTest.java
+++ b/server/src/test/java/com/vaadin/data/BinderTest.java
@@ -1542,6 +1542,29 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
     }
 
     @Test
+    public void invalidUsage_modifyFieldsInsideValidator_binderDoesNotThrow() {
+        TextField field = new TextField();
+
+        AtomicBoolean validatorIsExecuted = new AtomicBoolean();
+        binder.forField(field).asRequired().withValidator((val, context) -> {
+            nameField.setValue("foo");
+            ageField.setValue("bar");
+            validatorIsExecuted.set(true);
+            return ValidationResult.ok();
+        }).bind(Person::getEmail, Person::setEmail);
+
+        binder.forField(nameField).bind(Person::getFirstName,
+                Person::setFirstName);
+        binder.forField(ageField).bind(Person::getLastName,
+                Person::setLastName);
+
+        binder.setBean(new Person());
+
+        field.setValue("baz");
+        // mostly self control, the main check is: not exception is thrown
+        assertTrue(validatorIsExecuted.get());
+    }    
+
     public void setBean_readOnlyBinding_propertyBinding_valueIsNotUpdated() {
         Binder<ExampleBean> binder = new Binder<>(ExampleBean.class);