MDL-36167: Assignment quickgrading fix when there is no grade (ensure…

… feedback still saves)

This patch modifies the previous on by Luke Tucker so that the lastmodified hidden field
is always added to the quickgrading form even if there is no grade for the assignment. This
ensures that the lastmodified checks still work (to prevent teachers overwriting each
others feedback) and feedback is saved when there is no grade.

mod/assign/locallib.php

@@ -1022,6 +1022,8 @@ public function display_grade($grade, $editing, $userid=0, $modified=0) {
 
         static $scalegrades = array();
 
+        $o = '';
+
         if ($this->get_instance()->grade >= 0) {
             // Normal number
             if ($editing && $this->get_instance()->grade > 0) {
@@ -1030,17 +1032,20 @@ public function display_grade($grade, $editing, $userid=0, $modified=0) {
                 } else {
                     $displaygrade = format_float($grade);
                 }
-                $o = '<label class="accesshide" for="quickgrade_' . $userid . '">' . get_string('usergrade', 'assign') . '</label>';
-                $o .= '<input type="text" id="quickgrade_' . $userid . '" name="quickgrade_' . $userid . '" value="' . $displaygrade
-                        . '" size="6" maxlength="10" class="quickgrade"/>';
+                $o .= '<label class="accesshide" for="quickgrade_' . $userid . '">' . get_string('usergrade', 'assign') . '</label>';
+                $o .= '<input type="text" id="quickgrade_' . $userid . '" name="quickgrade_' . $userid . '" value="' . 
+                      $displaygrade . '" size="6" maxlength="10" class="quickgrade"/>';
                 $o .= '&nbsp;/&nbsp;' . format_float($this->get_instance()->grade,2);
                 $o .= '<input type="hidden" name="grademodified_' . $userid . '" value="' . $modified . '"/>';
                 return $o;
             } else {
+                $o .= '<input type="hidden" name="grademodified_' . $userid . '" value="' . $modified . '"/>';
                 if ($grade == -1 || $grade === null) {
-                    return '-';
+                    $o .= '-';
+                    return $o;
                 } else {
-                    return format_float(($grade),2) .'&nbsp;/&nbsp;'. format_float($this->get_instance()->grade,2);
+                    $o .= format_float(($grade),2) .'&nbsp;/&nbsp;'. format_float($this->get_instance()->grade,2);
+                    return $o;
                 }
             }
 
@@ -1050,11 +1055,12 @@ public function display_grade($grade, $editing, $userid=0, $modified=0) {
                 if ($scale = $DB->get_record('scale', array('id'=>-($this->get_instance()->grade)))) {
                     $this->cache['scale'] = make_menu_from_list($scale->scale);
                 } else {
-                    return '-';
+                    $o .= '-';
+                    return $o;
                 }
             }
             if ($editing) {
-                $o = '<label class="accesshide" for="quickgrade_' . $userid . '">' . get_string('usergrade', 'assign') . '</label>';
+                $o .= '<label class="accesshide" for="quickgrade_' . $userid . '">' . get_string('usergrade', 'assign') . '</label>';
                 $o .= '<select name="quickgrade_' . $userid . '" class="quickgrade">';
                 $o .= '<option value="-1">' . get_string('nograde') . '</option>';
                 foreach ($this->cache['scale'] as $optionid => $option) {
@@ -1070,9 +1076,11 @@ public function display_grade($grade, $editing, $userid=0, $modified=0) {
             } else {
                 $scaleid = (int)$grade;
                 if (isset($this->cache['scale'][$scaleid])) {
-                    return $this->cache['scale'][$scaleid];
+                    $o .= $this->cache['scale'][$scaleid];
+                    return $o;
                 }
-                return '-';
+                $o .= '-';
+                return $o;
             }
         }
     }
@@ -3448,12 +3456,12 @@ private function process_save_quick_grades() {
         // gets a list of possible users and look for values based upon that.
         foreach ($participants as $userid => $unused) {
             $modified = optional_param('grademodified_' . $userid, -1, PARAM_INT);
-            // gather the userid, updated grade and last modified value
+            // Gather the userid, updated grade and last modified value.
             $record = new stdClass();
             $record->userid = $userid;
             $gradevalue = optional_param('quickgrade_' . $userid, '', PARAM_TEXT);
             if($modified >= 0) {
-                $record->grade = unformat_float(required_param('quickgrade_' . $record->userid, PARAM_TEXT));
+                $record->grade = unformat_float(optional_param('quickgrade_' . $record->userid, -1, PARAM_TEXT));
             }
             $record->lastmodified = $modified;
             $record->gradinginfo = grade_get_grades($this->get_course()->id, 'mod', 'assign', $this->get_instance()->id, array($userid));
@@ -3491,8 +3499,7 @@ private function process_save_quick_grades() {
             foreach ($this->feedbackplugins as $plugin) {
                 if ($plugin->is_visible() && $plugin->is_enabled() && $plugin->supports_quickgrading()) {
                     if ($plugin->is_quickgrading_modified($modified->userid, $grade)) {
-                        if ($modified->lastmodified >= 0 &&
-                            (int)$current->lastmodified > (int)$modified->lastmodified) {
+                        if ((int)$current->lastmodified > (int)$modified->lastmodified) {
                             return get_string('errorrecordmodified', 'assign');
                         } else {
                             $modifiedusers[$modified->userid] = $modified;