ACP2E-3523: Issue with Default Attribute Option Value Behavior for Multiselect

Author: aplapana

app/code/Magento/Catalog/Controller/Adminhtml/Product/Attribute/Save.php

@@ -271,7 +271,7 @@ public function execute()
             if (array_key_exists('reset_is-default_option', $data) && $data['reset_is-default_option']) {
                 unset($data['reset_is-default_option']);
                 $data['default_value'] = null;
-            } else {
+            } elseif(isset($data['default'])) {
                 $data['default_value'] = implode(",", $data['default']);
             }
 

app/code/Magento/Catalog/view/adminhtml/templates/catalog/product/attribute/js.phtml

@@ -7,6 +7,7 @@ use Magento\Catalog\Helper\Data;
 
 /** @var \Magento\Backend\Block\Template $block */
 /** @var \Magento\Framework\View\Helper\SecureHtmlRenderer $secureRenderer */
+/** @var $escaper \Magento\Framework\Escaper */
 ?>
 
 <?php
@@ -234,7 +235,7 @@ script;
         elseif ($one == '_scope'):
             $scriptString .= 'scopeVisibility = false;';
         else:
-            $scriptString .= "setRowVisibility('" . $block->escapeJs($one) . "', false);";
+            $scriptString .= "setRowVisibility('" . $escaper->escapeJs($one) . "', false);";
         endif;
     endforeach;
     $scriptString .= <<<script