From 407bd0cd72c073aa9bf76d39c89acabcf660b560 Mon Sep 17 00:00:00 2001
From: Joseph Schorr <joseph.schorr@coreos.com>
Date: Thu, 23 Apr 2015 14:44:08 -0400
Subject: [PATCH] Make the image history tree more resistant to odd structures

---
 static/js/graphing.js | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/static/js/graphing.js b/static/js/graphing.js
index 7ea5203ec..6b945c877 100644
--- a/static/js/graphing.js
+++ b/static/js/graphing.js
@@ -568,7 +568,10 @@ ImageHistoryTree.prototype.collapseNodes_ = function(node) {
     var current = node;
     var previous = node;
     var encountered = [];
-    while (current.children.length == 1 && current.tags.length == 0) {
+    while (current.children
+          && current.children.length == 1
+           && curren.tags
+           && current.tags.length == 0) {
       encountered.push(current);
       previous = current;
       current = current.children[0];
@@ -591,8 +594,10 @@ ImageHistoryTree.prototype.collapseNodes_ = function(node) {
     }
   }
 
-  for (var i = 0; i < node.children.length; ++i) {
-    this.collapseNodes_(node.children[i]);
+  if (node.children) {
+    for (var i = 0; i < node.children.length; ++i) {
+      this.collapseNodes_(node.children[i]);
+    }
   }
 };