Merge pull request #3504 from rbayet/fix-3500-tracker-prevent-loss-of…

…-vary-cookie

[Tracker] Fixes #3500 loss of X-Magento-Vary cookie

src/module-elasticsuite-tracker/Model/App/Response/Http/TrackerResponse.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * DISCLAIMER
+ *
+ * Do not edit or add to this file if you wish to upgrade this module to newer versions in the future.
+ *
+ * @category  Smile
+ * @package   Smile\ElasticsuiteTracker
+ * @author    Richard BAYET <[email protected]>
+ * @copyright 2025 Smile
+ * @license   Open Software License ("OSL") v. 3.0
+ */
+
+namespace Smile\ElasticsuiteTracker\Model\App\Response\Http;
+
+use Magento\Framework\App\PageCache\NotCacheableInterface;
+use Magento\Framework\App\Response\Http;
+
+/**
+ * Custom Http Response object for the elasticsuite/tracker/hit legacy controller.
+ * Using this object instead of a classic Http response object
+ * - prevents \Magento\PageCache\Model\App\Response\HttpPlugin from being triggered in the first place
+ * - and if it was triggered, makes sure that the sendVary method is not called
+ *   - which would result in the loss of the Vary cookie if the user is logged in.
+ *
+ * @category Smile
+ * @package  Smile\ElasticsuiteTracker
+ */
+class TrackerResponse extends Http implements NotCacheableInterface
+{
+}

src/module-elasticsuite-tracker/etc/di.xml

@@ -121,6 +121,18 @@
     <type name="Magento\Framework\Session\SessionStartChecker">
         <plugin name="elasticsuite_tracker_disable_session" type="Smile\ElasticsuiteTracker\Plugin\SessionStartCheckerPlugin"/>
     </type>
+    <!-- Prevent lack of session start to lead to an empty HttpContext and a removal of the Vary cookie by the FPC in h.png/pixel mode -->
+    <virtualType name="TrackerResponseContext"
+                 type="Magento\Framework\App\Action\Context">
+        <arguments>
+            <argument name="response" xsi:type="object">Smile\ElasticsuiteTracker\Model\App\Response\Http\TrackerResponse</argument>
+        </arguments>
+    </virtualType>
+    <type name="Smile\ElasticsuiteTracker\Controller\Tracker\Hit">
+        <arguments>
+            <argument name="context" xsi:type="object">TrackerResponseContext</argument>
+        </arguments>
+    </type>
 
     <!-- Example of extending the page map identifier -->
     <type name="Smile\ElasticsuiteTracker\Model\Event\Processor\MapPageIdentifier">