Issue #2939008 by jsacksick: There is no formatter for the commerce_plugin_item field type

Author: jsacksick

commerce.module

@@ -35,6 +35,23 @@ function commerce_field_widget_info_alter(array &$info) {
   }
 }
 
+/**
+ * Implements hook_field_formatter_info_alter().
+ *
+ * Exposes the commerce_plugin_item_default formatter for each of the field
+ * type's derivatives, since core does not do it automatically.
+ */
+function commerce_field_formatter_info_alter(array &$info) {
+  if (isset($info['commerce_plugin_item_default'])) {
+    $field_type_manager = \Drupal::service('plugin.manager.field.field_type');
+    foreach ($field_type_manager->getDefinitions() as $key => $definition) {
+      if ($definition['id'] == 'commerce_plugin_item') {
+        $info['commerce_plugin_item_default']['field_types'][] = $key;
+      }
+    }
+  }
+}
+
 /**
  * Implements hook_field_widget_form_alter().
  *

src/Plugin/Field/FieldFormatter/PluginItemDefaultFormatter.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Drupal\commerce\Plugin\Field\FieldFormatter;
+
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Field\FormatterBase;
+
+/**
+ * Plugin implementation of the 'commerce_plugin_item_default' formatter.
+ *
+ * @FieldFormatter(
+ *   id = "commerce_plugin_item_default",
+ *   label = @Translation("Default"),
+ *   field_types = {
+ *     "commerce_plugin_item"
+ *   }
+ * )
+ */
+class PluginItemDefaultFormatter extends FormatterBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function viewElements(FieldItemListInterface $items, $langcode) {
+    $elements = [];
+    foreach ($items as $delta => $item) {
+      $target_definition = $item->getTargetDefinition();
+      if (!empty($target_definition['label'])) {
+        $elements[$delta] = [
+          '#markup' => $target_definition['label'],
+        ];
+      }
+      else {
+        $elements[$delta] = [
+          '#markup' => $target_definition['id'],
+        ];
+      }
+    }
+
+    return $elements;
+  }
+
+}

src/Plugin/Field/FieldType/PluginItem.php

@@ -16,7 +16,7 @@
  *   description = @Translation("Stores configuration for a plugin."),
  *   category = @Translation("Commerce"),
  *   default_widget = "commerce_plugin_select",
- *   default_formatter = "string",
+ *   default_formatter = "commerce_plugin_item_default",
  *   deriver = "\Drupal\commerce\Plugin\Field\FieldType\PluginItemDeriver"
  * )
  */