From 9254cda0db47bd834a5081b4598baa7bd4b822ab Mon Sep 17 00:00:00 2001
From: Joseph Schorr <joseph.schorr@coreos.com>
Date: Wed, 18 Mar 2015 13:43:57 -0400
Subject: [PATCH] Fix NPE

---
 static/js/graphing.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/static/js/graphing.js b/static/js/graphing.js
index cbb4fe0bc..7ccfcf2df 100644
--- a/static/js/graphing.js
+++ b/static/js/graphing.js
@@ -563,7 +563,7 @@ ImageHistoryTree.prototype.determineMaximumHeight_ = function(node) {
  * compact.
  */
 ImageHistoryTree.prototype.collapseNodes_ = function(node) {
-  if (node.children.length == 1) {
+  if (node.children && node.children.length == 1) {
     // Keep searching downward until we find a node with more than a single child.
     var current = node;
     var previous = node;