MAGETWO-71255: Merge 2.2 into develop mainline (2.3)

- stabilize builds

Author: cpartica

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

@@ -160,17 +160,17 @@ private function checkUniqueOption(DataObject $response, array $options = null)
         if (is_array($options)
             && isset($options['value'])
             && isset($options['delete'])
-            && !$this->isUniqueAdminValues($options['value'], $options['delete'])
+            && !empty($options['value'])
+            && !empty($options['delete'])
         ) {
             $duplicates = $this->isUniqueAdminValues($options['value'], $options['delete']);
-            if ($duplicates) {
+            if (!empty($duplicates)) {
                 $this->setMessageToResponse(
                     $response,
                     [__('The value of Admin must be unique. (%1)', implode(', ', $duplicates))]
                 );
-
-                $response->setError(true);
             }
+            $response->setError(true);
         }
         return $this;
     }

app/code/Magento/Catalog/Test/Unit/Controller/Adminhtml/Product/Attribute/ValidateTest.php

@@ -233,7 +233,7 @@ public function provideUniqueData()
                         "option_1" => "",
                         "option_2" => "",
                     ]
-                ], false
+                ], true
             ],
             'duplicate and deleted' => [
                 [