From 2ff7800ae8874153d3f2d5a8616a7c13377c10e9 Mon Sep 17 00:00:00 2001
From: Petr Skoda <commits@skodak.org>
Date: Wed, 29 Feb 2012 07:58:11 +0100
Subject: [PATCH] MDL-31807 fix invalid nulls in cohort components

Credit goes to Stephen.
---
 cohort/lib.php | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/cohort/lib.php b/cohort/lib.php
index 9a084eb63b720..7b398f3540473 100644
--- a/cohort/lib.php
+++ b/cohort/lib.php
@@ -71,8 +71,9 @@ function cohort_add_cohort($cohort) {
  */
 function cohort_update_cohort($cohort) {
     global $DB;
-    if (isset($cohort->component) and empty($cohort->component)) {
-        $cohort->component = NULL;
+    if (property_exists($cohort, 'component') and empty($cohort->component)) {
+        // prevent NULLs
+        $cohort->component = '';
     }
     $cohort->timemodified = time();
     $DB->update_record('cohort', $cohort);