Fixed problem during fresh installation fixes #8

As the newly installed attributes are not available immediately we have to refresh the cache manually during the setup

Setup/InstallData.php

@@ -49,21 +49,29 @@ class InstallData implements InstallDataInterface
      */
     protected $_configResource;
 
+    /**
+     * @var \Magento\Eav\Model\Config
+     */
+    protected $_eavConfig;
+
     /**
      * Constructor
      *
      * @param \Magento\Eav\Setup\EavSetupFactory $eavSetupFactory
      * @param \Magento\Catalog\Api\ProductAttributeOptionManagementInterface $productAttributeOptionManagementInterface
      * @param \Magento\Config\Model\ResourceModel\Config $configResource
+     * @param \Magento\Eav\Model\Config $eavConfig
      */
     public function __construct(
         \Magento\Eav\Setup\EavSetupFactory $eavSetupFactory,
         \Magento\Catalog\Api\ProductAttributeOptionManagementInterface $productAttributeOptionManagementInterface,
-        \Magento\Config\Model\ResourceModel\Config $configResource
+        \Magento\Config\Model\ResourceModel\Config $configResource,
+        \Magento\Eav\Model\Config $eavConfig
     ){
         $this->_eavSetupFactory = $eavSetupFactory;
         $this->_productAttributeOptionManagementInterface = $productAttributeOptionManagementInterface;
         $this->_configResource = $configResource;
+        $this->_eavConfig = $eavConfig;
     }
 
     /**
@@ -153,6 +161,8 @@ public function install(ModuleDataSetupInterface $setup, ModuleContextInterface
             ]);
         }
 
+        // clean cache so that newly created attributes will be loaded from database
+        $this->_eavConfig->clear();
         $this->_setSystemConfiguration();
     }
 
@@ -269,4 +279,4 @@ protected function _setSystemConfiguration()
             0
         );
     }
-}
+}