MDL-18402 Setting aggregationcoef to 1 if left empty

lib/grade/grade_item.php

@@ -247,6 +247,7 @@ class grade_item extends grade_object {
      * In addition to update() as defined in grade_object, handle the grade_outcome and grade_scale objects.
      * Force regrading if necessary, rounds the float numbers using php function,
      * the reason is we need to compare the db value with computed number to skip regrading if possible.
+     * Also sets aggregationcoef to 1 if unset: 0 would negate it in the mean
      * @param string $source from where was the object inserted (mod/forum, manual, etc.)
      * @return boolean success
      */
@@ -268,6 +269,10 @@ class grade_item extends grade_object {
 
         $this->timemodified = time();
 
+        if (is_null($this->aggregationcoef)) {
+            $this->aggregationcoef = 1;
+        }
+
         $this->grademin        = grade_floatval($this->grademin);
         $this->grademax        = grade_floatval($this->grademax);
         $this->multfactor      = grade_floatval($this->multfactor);
@@ -1878,7 +1883,7 @@ class grade_item extends grade_object {
         global $USER;
 
         // Determine which display type to use for this average
-        if ($USER->gradeediting[$this->courseid]) {
+        if (isset($USER->gradeediting) && $USER->gradeediting[$this->courseid]) {
             $displaytype = GRADE_DISPLAY_TYPE_REAL;
 
         } else if ($rangesdisplaytype == GRADE_REPORT_PREFERENCE_INHERIT) { // no ==0 here, please resave report and user prefs