Issue #3431332: FieldReference::buildFieldFormRow() checks a local variable that has never been set

Closes #3431332

src/Plugin/DisplayFieldsField/FieldReference.php

@@ -172,16 +172,16 @@ public function buildFieldFormRow($field_name, $field, $field_display_settings,
       '#field_name' => "display_fields_$field_name",
     ];
 
-    // Process values from formatter settings. (These are set via AJAX, so check them).
+    // Process values from formatter settings. (These are set via AJAX, so check them.)
     if (!empty($field_display_settings) && $form_state->get('plugin_settings_edit') == "display_fields_$field_name") {
       // We are currently editing this field's plugin settings. Display the
-      // settings form and submission buttons.
+      // settings form and the submission buttons.
       $row['plugin']['settings_edit_form'] = [];
 
       // Generate the settings form and allow other modules to alter it.
       $settings_form = $plugin->settingsForm($complete_form, $form_state);
 
-      if ($settings_form || $third_party_settings_form) {
+      if ($settings_form) {
         $row['plugin']['#cell_attributes'] = ['colspan' => 3];
         $row['plugin']['settings_edit_form'] = [
           '#type' => 'container',
@@ -189,7 +189,6 @@ public function buildFieldFormRow($field_name, $field, $field_display_settings,
           '#parents' => ['fields', "display_fields_$field_name", 'settings_edit_form'],
           'label' => ['#markup' => t('Plugin settings')],
           'settings' => $settings_form,
-          // 'third_party_settings' => $third_party_settings_form,
           'actions' => [
             '#type' => 'actions',
             'save_settings' => $base_button + [
@@ -232,15 +231,15 @@ public function buildFieldFormRow($field_name, $field, $field_display_settings,
 
       // Check the selected plugin settings to display the edit link.
       $settings_form = $plugin->settingsForm($complete_form, $form_state);
-      if (!empty($settings_form) || !empty($third_party_settings_form)) {
+      if (!empty($settings_form)) {
         $row['settings_edit'] += $base_button + [
           '#type' => 'image_button',
           '#name' => "display_fields_{$field_name}_settings_edit",
           '#src' => 'core/misc/icons/787878/cog.svg',
           '#attributes' => ['alt' => t('Edit')],
           '#op' => 'edit',
-          // Do not check errors for the Edit button, but make sure we get
-          // the value of the plugin type select.
+          // Do not check errors for the Edit button, but make sure we get the
+          // value of the plugin type select.
           '#limit_validation_errors' => [['fields', "display_fields_$field_name", 'type']],
           '#prefix' => '<div class="field-plugin-settings-edit-wrapper">',
           '#suffix' => '</div>',