MAGETWO-55513: Portdown MAGETWO-51015 down to M2.0.x branch

Author: Yuriy Denyshchenko

app/code/Magento/Eav/Model/Entity/Attribute/Source/Table.php

@@ -66,7 +66,7 @@ public function getAllOptions($withEmpty = true, $defaultValues = false)
         }
         $options = $defaultValues ? $this->_optionsDefault[$storeId] : $this->_options[$storeId];
         if ($withEmpty) {
-            array_unshift($options, ['label' => '', 'value' => '']);
+            $options = $this->addEmptyOption($options);
         }
 
         return $options;
@@ -89,11 +89,21 @@ public function getSpecificOptions($ids, $withEmpty = true)
             ->load()
             ->toOptionArray();
         if ($withEmpty) {
-            array_unshift($options, ['label' => '', 'value' => '']);
+            $options = $this->addEmptyOption($options);
         }
         return $options;
     }
 
+    /**
+     * @param array $options
+     * @return array
+     */
+    private function addEmptyOption(array $options)
+    {
+        array_unshift($options, ['label' => $this->getAttribute()->getIsRequired() ? '' : ' ', 'value' => '']);
+        return $options;
+    }
+
     /**
      * Get a text for option value
      *

dev/tests/api-functional/testsuite/Magento/Customer/Api/CustomerMetadataTest.php

@@ -101,7 +101,7 @@ public function getAttributeMetadataDataProvider()
                     AttributeMetadata::REQUIRED         => false,
                     AttributeMetadata::DATA_MODEL       => '',
                     AttributeMetadata::OPTIONS          => [
-                        ['label' => '', 'value' => ''],
+                        ['label' => ' ', 'value' => ''],
                         ['label' => 'Male', 'value' => '1'],
                         ['label' => 'Female', 'value' => '2'],
                         ['label' => 'Not Specified', 'value' => '3']