Treat fields as readonly when bound with null setter (#10477)

Fixes #10476

server/src/main/java/com/vaadin/data/Binder.java

@@ -228,6 +228,10 @@ public class Binder<BEAN> implements Serializable {
          * binder.forField(nameField).bind(Person::getName, Person::setName);
          * </pre>
          *
+         * <p>
+         * <strong>Note:</strong> when a {@code null} setter is given the field will be
+         * marked as readonly by invoking ({@link HasValue::setReadOnly}.
+         *
          * @param getter
          *            the function to get the value of the property to the
          *            field, not null
@@ -256,6 +260,10 @@ public class Binder<BEAN> implements Serializable {
          * an accessible setter; in that case the property value is never
          * updated and the binding is said to be <i>read-only</i>.
          *
+         * <p>
+         * <strong>Note:</strong> when the binding is <i>read-only</i> the field will be
+         * marked as readonly by invoking ({@link HasValue::setReadOnly}.
+         *
          * @param propertyName
          *            the name of the property to bind, not null
          * @return the newly created binding
@@ -741,6 +749,9 @@ public class Binder<BEAN> implements Serializable {
             if (getBinder().getBean() != null) {
                 binding.initFieldValue(getBinder().getBean());
             }
+            if (setter == null) {
+                binding.getField().setReadOnly(true);
+            }
             getBinder().fireStatusChangeEvent(false);
 
             bound = true;
@@ -1444,6 +1455,10 @@ public class Binder<BEAN> implements Serializable {
      * binder.bind(nameField, Person::getName, Person::setName);
      * </pre>
      *
+     * <p>
+     * <strong>Note:</strong> when a {@code null} setter is given the field will be
+     * marked as readonly by invoking ({@link HasValue::setReadOnly}.
+     *
      * @param <FIELDVALUE>
      *            the value type of the field
      * @param field

server/src/test/java/com/vaadin/data/BeanBinderTest.java

@@ -310,22 +310,29 @@ public class BeanBinderTest
         assertEquals(propertyValue, item.getReadOnlyProperty());
     }
 
+    @Test
+    public void bindReadOnlyPropertyShouldMarkFieldAsReadonly() {
+        binder.bind(nameField, "readOnlyProperty");
+
+        assertTrue("Name field should be readonly", nameField.isReadOnly());
+    }
+
     @Test
     public void setReadonlyShouldIgnoreBindingsForReadOnlyProperties() {
         binder.bind(nameField, "readOnlyProperty");
 
         binder.setReadOnly(true);
-        assertFalse("Name field should be ignored and not be readonly", nameField.isReadOnly());
+        assertTrue("Name field should be ignored and be readonly", nameField.isReadOnly());
 
         binder.setReadOnly(false);
-        assertFalse("Name field should be ignored and not be readonly", nameField.isReadOnly());
+        assertTrue("Name field should be ignored and be readonly", nameField.isReadOnly());
 
-        nameField.setReadOnly(true);
+        nameField.setReadOnly(false);
         binder.setReadOnly(true);
-        assertTrue("Name field should be ignored and be readonly", nameField.isReadOnly());
+        assertFalse("Name field should be ignored and not be readonly", nameField.isReadOnly());
 
         binder.setReadOnly(false);
-        assertTrue("Name field should be ignored and be readonly", nameField.isReadOnly());
+        assertFalse("Name field should be ignored and not be readonly", nameField.isReadOnly());
     }
 
     @Test

server/src/test/java/com/vaadin/data/BinderTest.java

@@ -616,11 +616,11 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
             .bind(Person::getAge, Person::setAge);
 
         binder.setReadOnly(true);
-        assertFalse("Name field should be ignored and not be readonly", nameField.isReadOnly());
+        assertTrue("Name field should be ignored but should be readonly", nameField.isReadOnly());
         assertTrue("Age field should be readonly", ageField.isReadOnly());
 
         binder.setReadOnly(false);
-        assertFalse("Name field should be ignored and remain not readonly", nameField.isReadOnly());
+        assertTrue("Name field should be ignored and should remain readonly", nameField.isReadOnly());
         assertFalse("Age field should not be readonly", ageField.isReadOnly());
 
         nameField.setReadOnly(false);
@@ -1044,4 +1044,15 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
                 Person::getFirstName, Person::setFirstName);
         binder.removeBinding(binding);
     }
+
+    @Test
+    public void bindWithNullSetterShouldMarkFieldAsReadonly() {
+        binder.bind(nameField, Person::getFirstName, null);
+        binder.forField(ageField)
+            .withConverter(new StringToIntegerConverter(""))
+            .bind(Person::getAge, Person::setAge);
+
+        assertTrue("Name field should be readonly", nameField.isReadOnly());
+        assertFalse("Name field should be readonly", ageField.isReadOnly());
+    }
 }

uitest/src/main/java/com/vaadin/tests/components/datefield/DateTextHandling.java

@@ -45,7 +45,7 @@ public class DateTextHandling extends AbstractTestUI {
         layout.addComponent(errorLabel);
 
         Binder<Void> binder = new Binder<>();
-        binder.forField(dateField).withStatusLabel(errorLabel).bind(o -> dateField.getValue(), null);
+        binder.forField(dateField).withStatusLabel(errorLabel).bind(o -> dateField.getValue(), (aVoid, date) -> {});
 
         Button buttonValidate = new Button("Validate!");
         buttonValidate.addClickListener(event1 -> {