6305 Resolved product custom option title save issue

Author: Madhumalak

app/code/Magento/Catalog/Model/Product/Option/Validator/DefaultValidator.php

@@ -106,7 +106,9 @@ protected function isValidOptionTitle($title, $storeId)
         if ($storeId > \Magento\Store\Model\Store::DEFAULT_STORE_ID && $title === null) {
             return true;
         }
-        if ($this->isEmpty($title)) {
+
+        // checking whether title is null and also changed is_empty to is_null
+        if ($this->isNull($title)) {
             return false;
         }
 
@@ -168,4 +170,15 @@ protected function isNegative($value)
     {
         return intval($value) < 0;
     }
+
+    /**
+     * check whether title is null
+     *
+     * @param $title
+     * @return bool
+     */
+    protected function isNull($title)
+    {
+        return is_null($title);
+    }
 }

app/code/Magento/Catalog/Model/ResourceModel/Product/Option/Value.php

@@ -256,7 +256,8 @@ protected function _saveValueTitles(AbstractModel $object)
                 $object->unsetData('title');
             }
 
-            if ($object->getTitle()) {
+            /*** Checking whether title is not null ***/
+            if ($object->getTitle()!= null) {
                 if ($existInCurrentStore) {
                     if ($storeId == $object->getStoreId()) {
                         $where = [