From ffb37d6826ade8cbac862ef680df2e3b0df298e5 Mon Sep 17 00:00:00 2001
From: Zhisheng Huang <zsh@fb.com>
Date: Tue, 16 Oct 2018 12:51:33 -0700
Subject: [PATCH] Add an assertion inside IGListAdapterUpdater to see if
 fromObjects contains duplicate identifiers

Summary: Verify our assumption that the `fromObjects` should never contain duplicate identifiers.

Reviewed By: calimarkus

Differential Revision: D10410190

fbshipit-source-id: 4952698fee6373224b4c8395778009540c5ae380
---
 Source/IGListAdapterUpdater.m | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Source/IGListAdapterUpdater.m b/Source/IGListAdapterUpdater.m
index 37c2be79..6166ca2f 100644
--- a/Source/IGListAdapterUpdater.m
+++ b/Source/IGListAdapterUpdater.m
@@ -132,6 +132,8 @@
         return;
     }
 
+    IGAssert(objectsWithDuplicateIdentifiersRemoved(fromObjects).count == fromObjects.count, @"The fromObjects has duplicate identifiers (it should already be dedupepd at this point).");
+    
     NSArray *toObjects = nil;
     if (toObjectsBlock != nil) {
         toObjects = objectsWithDuplicateIdentifiersRemoved(toObjectsBlock());