From 6b6d2a8c7dfde855e81a9b02ca38f69d6dfb9440 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Aleksander=20=C5=81ukasz?=
 <aleksander.lukasz@nowoczesnapolska.org.pl>
Date: Sun, 8 Dec 2013 13:40:58 +0100
Subject: [PATCH 1/1] smartxml: throw exception on transformation returning
 invalid change root

---
 src/smartxml/transformations.js | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/smartxml/transformations.js b/src/smartxml/transformations.js
index 25c0ec1..3f4b65f 100644
--- a/src/smartxml/transformations.js
+++ b/src/smartxml/transformations.js
@@ -90,7 +90,17 @@ toret.createGenericTransformation = function(desc, name) {
         run: function(options) {
             var changeRoot;
             if(!desc.undo && options.beUndoable) {
-                changeRoot = desc.getChangeRoot ? desc.getChangeRoot.call(this) : this.document.root;
+                if(desc.getChangeRoot) {
+                    changeRoot = desc.getChangeRoot.call(this);
+                    if(!changeRoot) {
+                        throw new Error(
+                            'Transformation {name} returned invalid change root value'
+                            .replace('{name}', name)
+                        );
+                    }
+                } else {
+                    changeRoot = this.document.root;
+                }
                 this.snapshot = changeRoot.clone();
                 this.changeRootPath = changeRoot.getPath();
             }
-- 
2.20.1