From 9a307dedd4cbed74fff42a7e79526adfd81d9c2f Mon Sep 17 00:00:00 2001
From: Taras Kruts <taras.kruts@lemberg.co.uk>
Date: Thu, 10 Nov 2016 16:28:35 +0200
Subject: [PATCH] Issue 2826357 by ribel: Fixed fatal error when session does
 not exists yet.

---
 src/Entity/Flagging.php | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/Entity/Flagging.php b/src/Entity/Flagging.php
index 78c92ca..4234e84 100644
--- a/src/Entity/Flagging.php
+++ b/src/Entity/Flagging.php
@@ -182,10 +182,11 @@ class Flagging extends ContentEntityBase implements FlaggingInterface {
    */
   public function postSave(EntityStorageInterface $storage, $update = TRUE) {
     if ($this->uid->entity && $this->uid->entity->isAnonymous()) {
-      $session = \Drupal::request()->getSession();
-      $session_flaggings = $session->get('flaggings', []);
-      $session_flaggings[] = $this->id();
-      $session->set('flaggings', $session_flaggings);
+      if ($session = \Drupal::request()->getSession()) {
+        $session_flaggings = $session->get('flaggings', []);
+        $session_flaggings[] = $this->id();
+        $session->set('flaggings', $session_flaggings);
+      }
     }
     parent::postSave($storage, $update);
 
-- 
2.6.1