From c3d4d3f7c15275e4f2712017ea18812fbf48b8be Mon Sep 17 00:00:00 2001
From: Damyon Wiese <damyon@moodle.com>
Date: Thu, 11 Aug 2016 14:39:34 +0800
Subject: [PATCH 1/2] MDL-55520 forms: Mod grade is changing values back to
 default

When a field is disabled in the page - no value is sent and modgrade is reverting
to the default. This change prevents the max grade from changing accidentally.
---
 lib/form/modgrade.php | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/form/modgrade.php b/lib/form/modgrade.php
index b33f4370cee..9fe780618e3 100644
--- a/lib/form/modgrade.php
+++ b/lib/form/modgrade.php
@@ -266,7 +266,8 @@ class MoodleQuickForm_modgrade extends MoodleQuickForm_group {
         $point = (isset($vals['modgrade_point'])) ? $vals['modgrade_point'] : null;
         $scale = (isset($vals['modgrade_scale'])) ? $vals['modgrade_scale'] : null;
         $rescalegrades = (isset($vals['modgrade_rescalegrades'])) ? $vals['modgrade_rescalegrades'] : null;
-        $return = $this->process_value($type, $scale, $point);
+
+        $return = $this->process_value($type, $scale, $point, $rescalegrades);
         return array($this->getName() => $return, $this->getName() . '_rescalegrades' => $rescalegrades);
     }
 
@@ -276,11 +277,17 @@ class MoodleQuickForm_modgrade extends MoodleQuickForm_group {
      * @param  string $type The value of the grade type select box. Can be 'none', 'scale', or 'point'
      * @param  string|int $scale The value of the scale select box.
      * @param  string|int $point The value of the point grade textbox.
+     * @param  string $rescalegrades The value of the rescalegrades select.
      * @return int The resulting value
      */
-    protected function process_value($type='none', $scale=null, $point=null) {
+    protected function process_value($type='none', $scale=null, $point=null, $rescalegrades=null) {
         global $COURSE;
         $val = 0;
+        if ($this->isupdate && $this->hasgrades && $this->canrescale && $this->currentgradetype == 'point' && empty($rescalegrades)) {
+            // If the maxgrade field is disabled with javascript, no value is sent with the form and mform assumes the default.
+            // If the user was forced to choose a rescale option - and they haven't - prevent any changes to the max grade.
+            return $this->currentgrade;
+        }
         switch ($type) {
             case 'point':
                 if ($this->validate_point($point) === true) {

From a95014f5b41f081432bbb8083ce40adf1fa2618e Mon Sep 17 00:00:00 2001
From: Damyon Wiese <damyon@moodle.com>
Date: Thu, 11 Aug 2016 15:13:31 +0800
Subject: [PATCH 2/2] MDL-55520 assign: Behat test for rescaling max grades bug

Verify the max grade is not silently changed back to 100 when you visit
and save the assignment settings form.
---
 mod/assign/tests/behat/rescale_grades.feature | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/mod/assign/tests/behat/rescale_grades.feature b/mod/assign/tests/behat/rescale_grades.feature
index 8b589ac4113..4d861e5d7c5 100644
--- a/mod/assign/tests/behat/rescale_grades.feature
+++ b/mod/assign/tests/behat/rescale_grades.feature
@@ -45,6 +45,22 @@ Feature: Check that the assignment grade can be rescaled when the max grade is c
     And I follow "View all submissions"
     Then "Student 1" row "Grade" column of "generaltable" table should contain "40.00"
 
+  Scenario: Update an assignment without touching the max grades
+    Given I follow "Edit settings"
+    And I expand all fieldsets
+    And I set the field "Rescale existing grades" to "No"
+    And I set the field "Maximum grade" to "80"
+    And I press "Save and display"
+    And I follow "Edit settings"
+    And I press "Save and display"
+    And I follow "Edit settings"
+    And I expand all fieldsets
+    And I set the field "Rescale existing grades" to "Yes"
+    And I set the field "Maximum grade" to "80"
+    When I press "Save and display"
+    And I follow "View all submissions"
+    Then "Student 1" row "Grade" column of "generaltable" table should contain "40.00"
+
   Scenario: Update the max grade for an assignment rescaling existing grades
     Given I follow "Edit settings"
     And I expand all fieldsets