Issue #3525775: [2.0.x] Cannot use computed entity reference bundle field in a component

src/Plugin/Derivative/EntityReferenceFieldPropertyDerivableContextDeriver.php

@@ -9,6 +9,34 @@ use Drupal\Component\Plugin\PluginBase;
  */
 class EntityReferenceFieldPropertyDerivableContextDeriver extends EntityFieldSourceDeriverBase {
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function getDerivativeDefinitionsForEntityBundleField(string $entity_type_id, string $bundle, string $field_name, array $base_plugin_derivative): void {
+    // Check if the field is an entity reference field and has no storage.
+    // Fields with storage are handled by
+    // `self::getDerivativeDefinitionsForEntityStorageFieldProperty()`.
+    if (
+      !empty($this->entityFieldsMetadata[$entity_type_id]["field_storages"][$field_name]) ||
+      empty($this->entityFieldsMetadata[$entity_type_id]["bundles"][$bundle]["fields"][$field_name]["entity_reference"])) {
+      return;
+    }
+    $id = implode(PluginBase::DERIVATIVE_SEPARATOR, [
+      $entity_type_id,
+      $bundle,
+      $field_name,
+      "target_id",
+    ]);
+    $this->derivatives[$id] = array_merge(
+      $base_plugin_derivative,
+      [
+        "id" => $id,
+        "label" => $this->t("Field prop: entity"),
+        "context_requirements" => array_merge($base_plugin_derivative["context_requirements"], ["field_granularity:item"]),
+        "tags" => array_merge($base_plugin_derivative["tags"], ["xxx"]),
+      ]);
+  }
+
   /**
    * {@inheritdoc}
    */