lazy validation

src/Task.php

@@ -270,16 +270,15 @@ class Task
 
     /**
      * @param string|Recurring $recur
-     * @throws TaskwarriorException
      */
     public function setRecurring($recur)
     {
-        if (is_string($recur)) {
+        if ($recur instanceof Recurring) {
-            $this->recur = new Recurring($recur);
-        } elseif ($recur instanceof Recurring) {
             $this->recur = $recur;
-        } elseif ($this->recur && is_null($recur)) {
+        } elseif ($recur) {
-            throw new TaskwarriorException('You cannot remove the recurrence from a recurring task.');
+            $this->recur = new Recurring($recur);
+        } else {
+            $this->recur = null;
         }
     }
 

src/TaskManager.php

@@ -205,9 +205,14 @@ class TaskManager
 
     /**
      * @param Task $task
+     * @throws TaskwarriorException
      */
     private function edit(Task $task)
     {
+        if ($task->isReccuring() && !$task->getRecurring()) {
+            throw new TaskwarriorException('You cannot remove the recurrence from a recurring task.');
+        }
+
         $this->taskwarrior->modify(
             [
                 'description' => $task->getDescription(),

tests/TaskManagerTest.php

@@ -541,6 +541,8 @@ class TaskManagerTest extends \PHPUnit_Framework_TestCase
         $this->taskManager->save($task1);
 
         $task1->setRecurring(null);
+
+        $this->taskManager->save($task1);
     }
 
     public function testRecurringNull()