fix exam checmout error when when user not exists

app/Repositories/ExamRepository.php

@@ -948,6 +948,12 @@ class ExamRepository extends BaseRepository
                 $uid = $examUser->uid;
                 $exam = $examUser->exam;
                 $currentLogPrefix = sprintf("$logPrefix, user: %s, exam: %s, examUser: %s", $uid, $examUser->exam_id, $examUser->id);
+                if (!$examUser->user) {
+                    do_log("$currentLogPrefix, user not exists, remove it!", 'error');
+                    $examUser->progresses()->delete();
+                    $examUser->delete();
+                    continue;
+                }
                 $locale = $examUser->user->locale;
                 if ($examUser->is_done) {
                     do_log("$currentLogPrefix, [is_done]");

app/Repositories/HitAndRunRepository.php

@@ -136,7 +136,8 @@ class HitAndRunRepository extends BaseRepository
                 $currentLog = "$logPrefix, [HANDLING] " . $row->toJson();
                 do_log($logPrefix);
                 if (!$row->user) {
-                    do_log("$currentLog, user not exists, skip!", 'error');
+                    do_log("$currentLog, user not exists, remove it!", 'error');
+                    $row->delete();
                     continue;
                 }
                 if (!$row->snatch) {
@@ -144,7 +145,8 @@ class HitAndRunRepository extends BaseRepository
                     continue;
                 }
                 if (!$row->torrent) {
-                    do_log("$currentLog, torrent not exists, skip!", 'error');
+                    do_log("$currentLog, torrent not exists, remove it!", 'error');
+                    $row->delete();
                     continue;
                 }