Issue #3071765 by joelpittet: Field without widget returning NULL instead of...

Issue #3071765 by joelpittet: Field without widget returning NULL instead of array in defaultValuesFormSubmit()

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

@@ -322,6 +322,7 @@ public function defaultValuesFormSubmit(array $element, array &$form, FormStateI
       $widget->extractFormValues($this, $element, $form_state);
       return $this->getValue();
     }
+    return [];
   }
 
   /**

core/tests/Drupal/Tests/Core/Field/FieldItemListTest.php

@@ -330,7 +330,7 @@ public function testDefaultValuesFormSubmit() {
     $field_list->expects($this->never())
       ->method('getValue');
 
-    $this->assertNull($field_list->defaultValuesFormSubmit([], $form, $form_state));
+    $this->assertArrayEquals([], $field_list->defaultValuesFormSubmit([], $form, $form_state));
   }
 
 }