Unable to insert widget with text value which contains }} string

app/code/Magento/Widget/Block/Adminhtml/Widget/Options.php

@@ -136,6 +136,7 @@ public function addFields()
      * @return \Magento\Framework\Data\Form\Element\AbstractElement
      * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      * @SuppressWarnings(PHPMD.NPathComplexity)
+     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
      */
     protected function _addField($parameter)
     {
@@ -158,6 +159,10 @@ protected function _addField($parameter)
             $data['value'] = $parameter->getValue();
         }
 
+        if ($parameter->getType() == 'text' && $data['value'] != '') {
+            $data['value'] = $this->_widget->decodeReservedChars($data['value']);
+        }
+
         //prepare unique id value
         if ($fieldName == 'unique_id' && $data['value'] == '') {
             $data['value'] = hash('sha256', microtime(1));

app/code/Magento/Widget/Model/Widget.php

@@ -131,6 +131,7 @@ public function getWidgetByClassType($type)
      */
     public function getConfigAsXml($type)
     {
+        // phpstan:ignore
         return $this->getXmlElementByType($type);
     }
 
@@ -293,6 +294,7 @@ public function getWidgetsArray($filters = [])
      * @param array $params Pre-configured Widget Params
      * @param bool $asIs Return result as widget directive(true) or as placeholder image(false)
      * @return string Widget directive ready to parse
+     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      */
     public function getWidgetDeclaration($type, $params = [], $asIs = true)
     {
@@ -304,6 +306,8 @@ public function getWidgetDeclaration($type, $params = [], $asIs = true)
             if ($name == 'conditions') {
                 $name = 'conditions_encoded';
                 $value = $this->conditionsHelper->encode($value);
+            } elseif ($this->isTextType($widget, $name)) {
+                $value = $this->encodeReservedChars($value);
             } elseif (is_array($value)) {
                 $value = implode(',', $value);
             } elseif (trim($value) == '') {
@@ -456,4 +460,65 @@ protected function sortParameters($firstElement, $secondElement)
         $bOrder = (int)$secondElement->getData('sort_order');
         return $aOrder < $bOrder ? -1 : ($aOrder > $bOrder ? 1 : 0);
     }
+
+    /**
+     * Encode reserved chars
+     *
+     * @param string $string
+     * @return string|string[]
+     */
+    private function encodeReservedChars($string)
+    {
+        $map = [
+            '{' => urlencode('{'),
+            '}' => urlencode('}')
+        ];
+
+        return str_replace(
+            array_keys($map),
+            array_values($map),
+            $string
+        );
+    }
+
+    /**
+     * Decode reserved chars
+     *
+     * @param string $string
+     * @return array
+     */
+    public function decodeReservedChars($string)
+    {
+        $map = [
+            '{' => urlencode('{'),
+            '}' => urlencode('}')
+        ];
+
+        return str_replace(
+            array_values($map),
+            array_keys($map),
+            $string
+        );
+    }
+
+    /**
+     * Is text type Widget parameter
+     *
+     * @param \Magento\Framework\DataObject $widget
+     * @param string $name
+     * @return bool
+     */
+    private function isTextType($widget, $name)
+    {
+        $parameters = $widget->getParameters();
+
+        if (isset($parameters[$name]) && is_object($parameters[$name])) {
+            $type = $parameters[$name]->getType();
+            if ($type == 'text') {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }