Issue #3004738 by NickWilde: Multiple Value Field Doesn't Render Attributes

core/includes/theme.inc

@@ -1606,6 +1606,7 @@ function template_preprocess_field(&$variables, $hook) {
 function template_preprocess_field_multiple_value_form(&$variables) {
   $element = $variables['element'];
   $variables['multiple'] = $element['#cardinality_multiple'];
+  $variables['attributes'] = $element['#attributes'];
 
   if ($variables['multiple']) {
     $table_id = Html::getUniqueId($element['#field_name'] . '_values');

core/modules/field/tests/src/Functional/FormTest.php

@@ -403,11 +403,12 @@ class FormTest extends FieldTestBase {
     $this->field['field_name'] = $field_name;
     FieldStorageConfig::create($field_storage)->save();
     FieldConfig::create($this->field)->save();
-    entity_get_form_display($this->field['entity_type'], $this->field['bundle'], 'default')
+    $form = entity_get_form_display($this->field['entity_type'], $this->field['bundle'], 'default')
       ->setComponent($field_name, [
         'type' => 'test_field_widget_multiple',
-      ])
-      ->save();
+      ]);
+    $form->save();
+    $session = $this->assertSession();
 
     // Display creation form.
     $this->drupalGet('entity_test/add');
@@ -435,6 +436,16 @@ class FormTest extends FieldTestBase {
     $this->assertRaw('this field cannot hold more than 4 values', 'Form validation failed.');
     // Check that the field values were not submitted.
     $this->assertFieldValues($entity_init, $field_name, [1, 2, 3]);
+
+    // Check that Attributes are rendered on the multivalue container if it is
+    // a multiple widget form.
+    $form->setComponent($field_name, [
+      'type' => 'entity_reference_autocomplete',
+    ])
+      ->save();
+    $this->drupalGet('entity_test/manage/' . $id . '/edit');
+    $name = str_replace('_', '-', $field_name);
+    $session->responseContains('data-drupal-selector="edit-' . $name . '"');
   }
 
   /**

core/modules/system/templates/field-multiple-value-form.html.twig

@@ -22,7 +22,13 @@
  */
 #}
 {% if multiple %}
-  <div class="js-form-item form-item">
+  {%
+    set classes = [
+      'js-form-item',
+      'form-item'
+    ]
+  %}
+  <div{{ attributes.addClass(classes) }}>
     {{ table }}
     {% if description.content %}
       <div{{ description.attributes.addClass('description') }} >{{ description.content }}</div>

core/themes/classy/templates/form/field-multiple-value-form.html.twig

@@ -20,7 +20,13 @@
  */
 #}
 {% if multiple %}
-  <div class="js-form-item form-item">
+  {%
+    set classes = [
+      'js-form-item',
+      'form-item'
+    ]
+  %}
+  <div{{ attributes.addClass(classes) }}>
     {{ table }}
     {% if description.content %}
       <div{{ description.attributes.addClass('description') }} >{{ description.content }}</div>

core/themes/stable/templates/form/field-multiple-value-form.html.twig

@@ -19,8 +19,15 @@
  * @see template_preprocess_field_multiple_value_form()
  */
 #}
+
 {% if multiple %}
-  <div class="js-form-item form-item">
+  {%
+    set classes = [
+      'js-form-item',
+      'form-item'
+    ]
+  %}
+  <div{{ attributes.addClass(classes) }}>
     {{ table }}
     {% if description.content %}
       <div{{ description.attributes.addClass('description') }} >{{ description.content }}</div>