From be52d0daced2b85d7fcb6d0df18bb1081da1c423 Mon Sep 17 00:00:00 2001
From: John Okely <john@moodle.com>
Date: Fri, 27 Jan 2017 14:59:33 +0800
Subject: [PATCH] MDL-37168 grade: Debugging if gradebook callbacks are not
 both present

---
 lib/gradelib.php | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/gradelib.php b/lib/gradelib.php
index 2417784bb9f..aa16239f80b 100644
--- a/lib/gradelib.php
+++ b/lib/gradelib.php
@@ -1379,9 +1379,10 @@ function grade_update_mod_grades($modinstance, $userid=0) {
         //new grading supported, force updating of grades
         $updateitemfunc($modinstance);
         $updategradesfunc($modinstance, $userid);
-
-    } else {
+    } else if (function_exists($updategradesfunc) xor function_exists($updateitemfunc)) {
         // Module does not support grading?
+        debugging("You have declared one of $updateitemfunc and $updategradesfunc but not both. " .
+                  "This will cause broken behaviour.", DEBUG_DEVELOPER);
     }
 
     return true;