MAGETWO-45316: Unable to Checkout if Persistent Shopping Card is enabled

removed observer
added plugin to checkout data provider

Author: Serhiy Shkolyarenko

app/code/Magento/Persistent/Model/Checkout/ConfigProviderPlugin.php

@@ -0,0 +1,83 @@
+<?php
+/**
+ * Copyright © 2015 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Persistent\Model\Checkout;
+
+use Magento\Persistent\Helper\Session as PersistentSession;
+use Magento\Persistent\Helper\Data as PersistentHelper;
+use Magento\Checkout\Model\Session as CheckoutSession;
+use Magento\Quote\Model\QuoteIdMaskFactory;
+use Magento\Customer\Model\Session as CustomerSession;
+
+class ConfigProviderPlugin
+{
+    /**
+     * @var PersistentSession
+     */
+    private $persistentSession;
+
+    /**
+     * @var PersistentHelper
+     */
+    private $persistentHelper;
+
+    /**
+     * @var CheckoutSession
+     */
+    private $checkoutSession;
+
+    /**
+     * @var QuoteIdMaskFactory
+     */
+    private $quoteIdMaskFactory;
+
+    /**
+     * @var CustomerSession
+     */
+    private $customerSession;
+
+    /**
+     * @param PersistentHelper $persistentHelper
+     * @param PersistentSession $persistentSession
+     * @param CheckoutSession $checkoutSession
+     * @param QuoteIdMaskFactory $quoteIdMaskFactory
+     * @param CustomerSession $customerSession
+     */
+    public function __construct(
+        PersistentHelper $persistentHelper,
+        PersistentSession $persistentSession,
+        CheckoutSession $checkoutSession,
+        QuoteIdMaskFactory $quoteIdMaskFactory,
+        CustomerSession $customerSession
+    ) {
+        $this->persistentHelper = $persistentHelper;
+        $this->persistentSession = $persistentSession;
+        $this->checkoutSession = $checkoutSession;
+        $this->quoteIdMaskFactory = $quoteIdMaskFactory;
+        $this->customerSession = $customerSession;
+    }
+
+    /**
+     * @param \Magento\Checkout\Model\DefaultConfigProvider $subject
+     * @param array $result
+     * @return array
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
+     */
+    public function afterGetConfig(\Magento\Checkout\Model\DefaultConfigProvider $subject, array $result)
+    {
+        if ($this->persistentHelper->isEnabled()
+                && $this->persistentSession->isPersistent()
+                && !$this->customerSession->isLoggedIn()
+        ) {
+            /** @var $quoteIdMask \Magento\Quote\Model\QuoteIdMask */
+            $quoteIdMask = $this->quoteIdMaskFactory->create();
+            $result['quoteData']['entity_id'] = $quoteIdMask->load(
+                $this->checkoutSession->getQuote()->getId(),
+                'quote_id'
+            )->getMaskedId();
+        }
+        return $result;
+    }
+}

app/code/Magento/Persistent/Observer/DisableGuestCheckoutObserver.php

@@ -29,4 +29,7 @@
     <type name="Magento\Quote\Model\AddressAdditionalDataProcessor">
         <plugin name="persistent_remember_me_checkbox_processor" type="Magento\Persistent\Model\Checkout\AddressDataProcessorPlugin" />
     </type>
+    <type name="Magento\Checkout\Model\DefaultConfigProvider">
+        <plugin name="mask_quote_id_substitutor" type="Magento\Persistent\Model\Checkout\ConfigProviderPlugin" />
+    </type>
 </config>

app/code/Magento/Persistent/Test/Unit/Observer/DisableGuestCheckoutObserverTest.php

@@ -38,9 +38,6 @@
         <observer name="persistent_customer" instance="Magento\Persistent\Observer\EmulateCustomerObserver" />
         <observer name="persistent_checkout" instance="Magento\Persistent\Observer\PreventExpressCheckoutObserver" />
     </event>
-    <event name="checkout_allow_guest">
-        <observer name="persistent" instance="Magento\Persistent\Observer\DisableGuestCheckoutObserver" />
-    </event>
     <event name="customer_customer_authenticated">
         <observer name="persistent" instance="Magento\Persistent\Observer\CustomerAuthenticatedEventObserver" />
     </event>