MDL-60685 assign: Do not falsely use admin user

When an assign_grades record is automatically populated, do not use the admin user as the default grader.

This would generate false information on the assignment summary screen and send false notifications from
the admin user.

mod/assign/locallib.php

@@ -2368,6 +2368,7 @@ public static function cron() {
         // Submissions are included if all are true:
         //   - The assignment is visible in the gradebook.
         //   - No previous notification has been sent.
+        //   - The grader was a real user, not an automated process.
         //   - If marking workflow is not enabled, the grade was updated in the past 24 hours, or
         //     if marking workflow is enabled, the workflow state is at 'released'.
         $sql = "SELECT g.id as gradeid, a.course, a.name, a.blindmarking, a.revealidentities,
@@ -2381,7 +2382,7 @@ public static function cron() {
             LEFT JOIN {assign_user_mapping} um ON g.id = um.userid AND um.assignment = a.id
                  WHERE ((a.markingworkflow = 0 AND g.timemodified >= :yesterday AND g.timemodified <= :today) OR
                         (a.markingworkflow = 1 AND uf.workflowstate = :wfreleased)) AND
-                       uf.mailed = 0 AND gri.hidden = 0
+                       g.grader > 0 AND uf.mailed = 0 AND gri.hidden = 0
               ORDER BY a.course, cm.id";
 
         $params = array(
@@ -3710,7 +3711,8 @@ public function get_user_grade($userid, $create, $attemptnumber=-1) {
                 $grade->timemodified = $grade->timecreated;
             }
             $grade->grade = -1;
-            $grade->grader = $USER->id;
+            // Do not set the grader id here as it would be the admin users which is incorrect.
+            $grade->grader = -1;
             if ($attemptnumber >= 0) {
                 $grade->attemptnumber = $attemptnumber;
             }
@@ -5096,8 +5098,10 @@ public function get_assign_feedback_status_renderable($user) {
                     $gradefordisplay = $this->display_grade($gradebookgrade->grade, false);
                 }
                 $gradeddate = $gradebookgrade->dategraded;
-                if (isset($grade->grader)) {
+                if (isset($grade->grader) && $grade->grader > 0) {
                     $grader = $DB->get_record('user', array('id' => $grade->grader));
+                } else if (isset($gradebookgrade->usermodified) && $gradebookgrade->usermodified > 0) {
+                    $grader = $DB->get_record('user', array('id' => $gradebookgrade->usermodified));
                 }
             }
 
@@ -5258,10 +5262,12 @@ protected function get_all_grades($userid) {
             // First lookup the grader info.
             if (isset($gradercache[$grade->grader])) {
                 $grade->grader = $gradercache[$grade->grader];
-            } else {
+            } else if ($grade->grader > 0) {
                 // Not in cache - need to load the grader record.
                 $grade->grader = $DB->get_record('user', array('id'=>$grade->grader));
-                $gradercache[$grade->grader->id] = $grade->grader;
+                if ($grade->grader) {
+                    $gradercache[$grade->grader->id] = $grade->grader;
+                }
             }
 
             // Now get the gradefordisplay.

mod/assign/tests/locallib_test.php

@@ -3882,6 +3882,7 @@ public function test_fix_null_grades($grade, $gradebookvalue) {
         $assign->get_user_grade($student->id, true);
 
         // Set the grade to something errant.
+        // We don't set the grader here, so we expect it to be -1 as a result.
         $DB->set_field(
             'assign_grades',
             'grade',
@@ -3899,6 +3900,7 @@ public function test_fix_null_grades($grade, $gradebookvalue) {
         // Check that the gradebook was updated with the assign grade. So we can guarentee test results later on.
         $expectedgrade = $grade == -1 ? null : $grade; // Assign sends null to the gradebook for -1 grades.
         $gradegrade = grade_grade::fetch(array('userid' => $student->id, 'itemid' => $assign->get_grade_item()->id));
+        $this->assertEquals(-1, $gradegrade->usermodified);
         $this->assertEquals($expectedgrade, $gradegrade->rawgrade);
 
         // Call fix_null_grades().
@@ -3910,6 +3912,9 @@ public function test_fix_null_grades($grade, $gradebookvalue) {
 
         $gradegrade = grade_grade::fetch(array('userid' => $student->id, 'itemid' => $assign->get_grade_item()->id));
 
+        $this->assertEquals(-1, $gradegrade->usermodified);
+        $this->assertEquals($gradebookvalue, $gradegrade->finalgrade);
+
         // Check that the grade was updated in the gradebook by fix_null_grades.
         $this->assertEquals($gradebookvalue, $gradegrade->finalgrade);
     }