Issue #2784015 by amateescu, jlbellido, Gogowitsch, krknth, ibustos: Widget...

Issue #2784015 by amateescu, jlbellido, Gogowitsch, krknth, ibustos: Widget validation crashes on ItemList violations for widgets with a custom errorElement() implementation

core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EntityReferenceAutocompleteWidget.php

@@ -118,7 +118,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
    * {@inheritdoc}
    */
   public function errorElement(array $element, ConstraintViolationInterface $error, array $form, FormStateInterface $form_state) {
-    return isset($element['target_id']) ? $element['target_id'] : FALSE;
+    return $element['target_id'];
   }
 
   /**

core/lib/Drupal/Core/Field/WidgetBase.php

@@ -423,21 +423,26 @@ public function flagErrors(FieldItemListInterface $items, ConstraintViolationLis
       if (Element::isVisibleElement($element)) {
         $handles_multiple = $this->handlesMultipleValues();
 
-        $violations_by_delta = [];
+        $violations_by_delta = $item_list_violations = [];
         foreach ($violations as $violation) {
           // Separate violations by delta.
           $property_path = explode('.', $violation->getPropertyPath());
           $delta = array_shift($property_path);
-          $violations_by_delta[$delta][] = $violation;
+          if (is_numeric($delta)) {
+            $violations_by_delta[$delta][] = $violation;
+          }
+          // Violations at the ItemList level are not associated to any delta.
+          else {
+            $item_list_violations[] = $violation;
+          }
           $violation->arrayPropertyPath = $property_path;
         }
 
         /** @var \Symfony\Component\Validator\ConstraintViolationInterface[] $delta_violations */
         foreach ($violations_by_delta as $delta => $delta_violations) {
-          // Pass violations to the main element:
-          // - if this is a multiple-value widget,
-          // - or if the violations are at the ItemList level.
-          if ($handles_multiple || !is_numeric($delta)) {
+          // Pass violations to the main element if this is a multiple-value
+          // widget.
+          if ($handles_multiple) {
             $delta_element = $element;
           }
           // Otherwise, pass errors by delta to the corresponding sub-element.
@@ -453,6 +458,13 @@ public function flagErrors(FieldItemListInterface $items, ConstraintViolationLis
             }
           }
         }
+
+        /** @var \Symfony\Component\Validator\ConstraintViolationInterface[] $item_list_violations */
+        // Pass violations to the main element without going through
+        // errorElement() if the violations are at the ItemList level.
+        foreach ($item_list_violations as $violation) {
+          $form_state->setError($element, $violation->getMessage());
+        }
       }
     }
   }

core/modules/system/tests/modules/entity_test/src/Entity/EntityTestConstraintViolation.php

@@ -3,6 +3,7 @@
 namespace Drupal\entity_test\Entity;
 
 use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
 
 /**
  * Defines the test entity class for testing entity constraint violations.
@@ -39,6 +40,16 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
     ]);
     $fields['name']->addConstraint('FieldWidgetConstraint', []);
 
+    // Add a field that uses a widget with a custom implementation for
+    // \Drupal\Core\Field\WidgetInterface::errorElement().
+    $fields['test_field'] = BaseFieldDefinition::create('integer')
+      ->setLabel(t('Test field'))
+      ->setDisplayOptions('form', [
+        'type' => 'number',
+        'weight' => 1,
+      ])
+      ->addConstraint('FieldWidgetConstraint', []);
+
     return $fields;
   }
 

core/modules/text/src/Plugin/Field/FieldWidget/TextareaWithSummaryWidget.php

@@ -87,15 +87,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
    */
   public function errorElement(array $element, ConstraintViolationInterface $violation, array $form, FormStateInterface $form_state) {
     $element = parent::errorElement($element, $violation, $form, $form_state);
-    if ($element === FALSE) {
-      return FALSE;
-    }
-    elseif (isset($violation->arrayPropertyPath[0])) {
-      return $element[$violation->arrayPropertyPath[0]];
-    }
-    else {
-      return $element;
-    }
+    return ($element === FALSE) ? FALSE : $element[$violation->arrayPropertyPath[0]];
   }
 
 }

core/tests/Drupal/KernelTests/Core/Entity/FieldWidgetConstraintValidatorTest.php

@@ -15,7 +15,7 @@
  */
 class FieldWidgetConstraintValidatorTest extends KernelTestBase {
 
-  public static $modules = ['entity_test', 'field', 'user', 'system'];
+  public static $modules = ['entity_test', 'field', 'field_test', 'user', 'system'];
 
   /**
    * {@inheritdoc}
@@ -54,7 +54,8 @@ public function testValidation() {
     $display->validateFormValues($entity, $form, $form_state);
 
     $errors = $form_state->getErrors();
-    $this->assertEqual($errors['name'], 'Widget constraint has failed.', 'Constraint violation is generated correctly');
+    $this->assertEqual($errors['name'], 'Widget constraint has failed.', 'Constraint violation at the field items list level is generated correctly');
+    $this->assertEqual($errors['test_field'], 'Widget constraint has failed.', 'Constraint violation at the field items list level is generated correctly for an advanced widget');
   }
 
   /**