MDL-56646 assign: Fix negative grades in restore

mod/assign/backup/moodle2/restore_assign_stepslib.php

@@ -243,7 +243,10 @@ class restore_assign_activity_structure_step extends restore_activity_structure_
             $flags->userid = $this->get_mappingid('user', $data->userid);
             $DB->insert_record('assign_user_flags', $flags);
         }
-
+        // Fix null grades that were rescaled.
+        if ($data->grade < 0 && $data->grade != -1) {
+            $data->grade = -1;
+        }
         $newitemid = $DB->insert_record('assign_grades', $data);
 
         // Note - the old contextid is required in order to be able to restore files stored in

mod/assign/locallib.php

@@ -8607,7 +8607,7 @@ class assign {
 
             // Fix the grades.
             $this->fix_null_grades();
-            set_config('has_rescaled_null_grades_' . $instance->id, 0, 'assign');
+            unset_config('has_rescaled_null_grades_' . $instance->id, 'assign');
 
             // Display the notice.
             $o .= $this->get_renderer()->notification(get_string('fixrescalednullgradesdone', 'assign'), 'notifysuccess');