Check if recurrence end date is disabled before saving it.

Summary: Ref T8357, Check if recurrence end date is disabled before saving it.

Test Plan: Create new event, before saving, leave "recurrence end date" unchecked, save, should not get an error.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Maniphest Tasks: T8357

Differential Revision: https://secure.phabricator.com/D13212

src/applications/calendar/controller/PhabricatorCalendarEventEditController.php

@@ -201,10 +201,12 @@ final class PhabricatorCalendarEventEditController
             PhabricatorCalendarEventTransaction::TYPE_FREQUENCY)
           ->setNewValue(array('rule' => $frequency));
 
-        $xactions[] = id(new PhabricatorCalendarEventTransaction())
-          ->setTransactionType(
-            PhabricatorCalendarEventTransaction::TYPE_RECURRENCE_END_DATE)
-          ->setNewValue($recurrence_end_date_value);
+        if (!$recurrence_end_date_value->isDisabled()) {
+          $xactions[] = id(new PhabricatorCalendarEventTransaction())
+            ->setTransactionType(
+              PhabricatorCalendarEventTransaction::TYPE_RECURRENCE_END_DATE)
+            ->setNewValue($recurrence_end_date_value);
+        }
       }
 
       $xactions[] = id(new PhabricatorCalendarEventTransaction())