From 581ea5013ae8164caed1f7e0603f9713be901f0d Mon Sep 17 00:00:00 2001
From: Mark Nelson <markn@moodle.com>
Date: Thu, 31 Mar 2016 15:07:22 +0800
Subject: [PATCH] MDL-52035 core_block: avoid PHP error when there is no region

This occurs when sharing a quiz via the LTI provider when it
adds a 'fake block' for quiz navigation. There may be other
occurrences.
---
 lib/blocklib.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/blocklib.php b/lib/blocklib.php
index 90cee6f62ed..9a7c9963d52 100644
--- a/lib/blocklib.php
+++ b/lib/blocklib.php
@@ -271,6 +271,9 @@ class block_manager {
      * @return boolean true if this region exists on this page.
      */
     public function is_known_region($region) {
+        if (empty($region)) {
+            return false;
+        }
         return array_key_exists($region, $this->regions);
     }