From 58ec5a315b16f3ebc45197833930100345f6fd7d Mon Sep 17 00:00:00 2001
From: Damyon Wiese <damyon@moodle.com>
Date: Mon, 28 Nov 2016 14:46:32 +0800
Subject: [PATCH] MDL-57176 blocks: Never never never dup blocks

Dont create duplicate blocks 'requiredbytheme' for any reason.
---
 lib/blocklib.php | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/blocklib.php b/lib/blocklib.php
index fb862e8c454..4990a2e5aa0 100644
--- a/lib/blocklib.php
+++ b/lib/blocklib.php
@@ -1053,6 +1053,11 @@ class block_manager {
             return;
         }
 
+        // Never add a duplicate block required by theme.
+        if ($DB->record_exists('block_instances', array('blockname' => $blockname, 'requiredbytheme' => 1))) {
+            return;
+        }
+
         $systemcontext = context_system::instance();
         $defaultregion = $this->get_default_region();
         // Add a special system wide block instance only for themes that require it.