From dcf562fb26264b0bc10796a281faeb41352eb9b7 Mon Sep 17 00:00:00 2001
From: John Estropia <rommel.estropia@gmail.com>
Date: Thu, 9 Jun 2016 17:57:15 +0900
Subject: [PATCH] ignore negative indexes when using ListMonitor's safeIndex
 API

---
 Sources/Observing/ListMonitor.swift | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Sources/Observing/ListMonitor.swift b/Sources/Observing/ListMonitor.swift
index a3d38da..e76a18e 100644
--- a/Sources/Observing/ListMonitor.swift
+++ b/Sources/Observing/ListMonitor.swift
@@ -121,13 +121,15 @@ public final class ListMonitor<T: NSManagedObject>: Hashable {
             !self.isPendingRefetch || NSThread.isMainThread(),
             "Attempted to access a \(cs_typeName(self)) outside the main thread while a refetch is in progress."
         )
-        
+        guard sectionIndex >= 0 && itemIndex >= 0 else {
+            
+            return nil
+        }
         guard let sections = self.fetchedResultsController.sections
             where sectionIndex < sections.count else {
                 
                 return nil
         }
-        
         let section = sections[sectionIndex]
         guard itemIndex < section.numberOfObjects else {