MDL-67116 course: Fix completion disabled for gradable items

The default value is an empty string (""), which in PHP evaluates to 0 when
cast to a string in our DML layer.

The fix is to forcibly make it null which is not cast to string in DML
for optional strings.

course/modlib.php

@@ -72,7 +72,11 @@ function add_moduleinfo($moduleinfo, $course, $mform = null) {
     $completion = new completion_info($course);
     if ($completion->is_enabled()) {
         $newcm->completion                = $moduleinfo->completion;
-        $newcm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
+        if ($moduleinfo->completiongradeitemnumber == '') {
+            $newcm->completiongradeitemnumber = null;
+        } else {
+            $newcm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
+        }
         $newcm->completionview            = $moduleinfo->completionview;
         $newcm->completionexpected        = $moduleinfo->completionexpected;
     }
@@ -524,7 +528,11 @@ function update_moduleinfo($cm, $moduleinfo, $course, $mform = null) {
         // the activity may be locked; if so, these should not be updated.
         if (!empty($moduleinfo->completionunlocked)) {
             $cm->completion = $moduleinfo->completion;
-            $cm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
+            if ($moduleinfo->completiongradeitemnumber == '') {
+                $cm->completiongradeitemnumber = null;
+            } else {
+                $cm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
+            }
             $cm->completionview = $moduleinfo->completionview;
         }
         // The expected date does not affect users who have completed the activity,

course/tests/modlib_test.php

@@ -112,6 +112,7 @@ public function test_get_moduleinfo_data() {
         $expecteddata->completionview     = $assigncm->completionview;
         $expecteddata->completionexpected = $assigncm->completionexpected;
         $expecteddata->completionusegrade = is_null($assigncm->completiongradeitemnumber) ? 0 : 1;
+        $expecteddata->completiongradeitemnumber = null;
         $expecteddata->showdescription    = $assigncm->showdescription;
         $expecteddata->tags               = core_tag_tag::get_item_tags_array('core', 'course_modules', $assigncm->id);
         $expecteddata->availabilityconditionsjson = null;

mod/workshop/lang/en/workshop.php

@@ -157,6 +157,8 @@
 $string['formatpeergradeoverweighted'] = '<span class="grade">{$a->grade}</span> <span class="gradinggrade">(<del>{$a->gradinggrade}</del> / <ins>{$a->gradinggradeover}</ins>)</span> @ <span class="weight">{$a->weight}</span>';
 $string['formatpeergradeweighted'] = '<span class="grade">{$a->grade}</span> <span class="gradinggrade">({$a->gradinggrade})</span> @ <span class="weight">{$a->weight}</span>';
 $string['givengrades'] = 'Grades given';
+$string['grade_submission_name'] = 'Submission';
+$string['grade_grading_name'] = 'Assessment';
 $string['gradecalculated'] = 'Calculated grade for submission';
 $string['gradedecimals'] = 'Decimal places in grades';
 $string['gradegivento'] = '&gt;';