Ignore relationship loops created remotely

app/src/androidTest/java/org/tasks/data/GoogleTaskDaoTests.kt

@@ -183,6 +183,21 @@ class GoogleTaskDaoTests : InjectingTestCase() {
         assertEquals("abcd", googleTaskDao.getByTaskId(1)!!.remoteParent)
     }
 
+    @Test
+    fun ignoreSelfParent() = runBlocking {
+        insert(
+            newCaldavTask(
+                with(TASK, 1),
+                with(REMOTE_ID, "123"),
+                with(REMOTE_PARENT, "123")
+            )
+        )
+
+        caldavDao.updateParents()
+
+        assertEquals(0, taskDao.fetch(1)!!.parent)
+    }
+
     @Test
     fun updateParents() = runBlocking {
         insert(newCaldavTask(with(TASK, 1), with(REMOTE_ID, "123")))

data/src/commonMain/kotlin/org/tasks/data/dao/CaldavDao.kt

@@ -296,7 +296,7 @@ GROUP BY caldav_lists.cdl_uuid
         )
         UPDATE tasks
         SET parent = IFNULL(
-            (SELECT parent_id FROM parent_map WHERE task_id = tasks._id),
+            (SELECT parent_id FROM parent_map WHERE task_id = tasks._id AND tasks._id != parent_id),
             0
         )
         WHERE _id IN (