From fd6a31febfd549ce99d6d4a39cd2c2126933174e Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Wed, 1 Jun 2016 15:24:46 -0400
Subject: [PATCH] update duplicate key warning message

---
 src/core/vdom/patch.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/core/vdom/patch.js b/src/core/vdom/patch.js
index f6d13a91..0b319c3f 100644
--- a/src/core/vdom/patch.js
+++ b/src/core/vdom/patch.js
@@ -221,9 +221,10 @@ export function createPatchFunction (backend) {
           newStartVnode = newCh[++newStartIdx]
         } else {
           elmToMove = oldCh[idxInOld]
+          /* istanbul ignore if */
           if (process.env.NODE_ENV !== 'production' && !elmToMove) {
             warn(
-              'Duplicate track-by key: ' + idxInOld + '. ' +
+              'It seems there are duplicate track-by keys that is causing an update error. ' +
               'Make sure each v-for item has a unique track-by key.'
             )
           }