MDL-37039 Assignment - Do not apply filters to grading table for offl…

…ine assignments

Because the filters do not make sense for offline assignments, they are hidden. But if the active filter
prevents you from seeing any assignments you cannot change it. This change makes it so the filters are
also not applied when the assignment is an offline assignment.

mod/assign/gradingtable.php

@@ -140,19 +140,22 @@ public function __construct(assign $assignment,
         $where = 'u.id ' . $userwhere;
         $params = array_merge($params, $userparams);
 
-        if ($filter == ASSIGN_FILTER_SUBMITTED) {
-            $where .= ' AND s.timecreated > 0 ';
-        }
-        if ($filter == ASSIGN_FILTER_REQUIRE_GRADING) {
-            $where .= ' AND (s.timemodified IS NOT NULL AND
-                             s.status = :submitted AND
-                             (s.timemodified > g.timemodified OR g.timemodified IS NULL))';
-            $params['submitted'] = ASSIGN_SUBMISSION_STATUS_SUBMITTED;
-        }
-        if (strpos($filter, ASSIGN_FILTER_SINGLE_USER) === 0) {
-            $userfilter = (int) array_pop(explode('=', $filter));
-            $where .= ' AND (u.id = :userid)';
-            $params['userid'] = $userfilter;
+        // The filters do not make sense when there are no submissions, so do not apply them.
+        if ($this->assignment->is_any_submission_plugin_enabled()) {
+            if ($filter == ASSIGN_FILTER_SUBMITTED) {
+                $where .= ' AND s.timecreated > 0 ';
+            }
+            if ($filter == ASSIGN_FILTER_REQUIRE_GRADING) {
+                $where .= ' AND (s.timemodified IS NOT NULL AND
+                                 s.status = :submitted AND
+                                 (s.timemodified > g.timemodified OR g.timemodified IS NULL))';
+                $params['submitted'] = ASSIGN_SUBMISSION_STATUS_SUBMITTED;
+            }
+            if (strpos($filter, ASSIGN_FILTER_SINGLE_USER) === 0) {
+                $userfilter = (int) array_pop(explode('=', $filter));
+                $where .= ' AND (u.id = :userid)';
+                $params['userid'] = $userfilter;
+            }
         }
         $this->set_sql($fields, $from, $where, $params);