From 95d7d373a581746ce68ada33dd890ecc385245ed Mon Sep 17 00:00:00 2001
From: =?utf8?q?Aleksander=20=C5=81ukasz?=
 <aleksander.lukasz@nowoczesnapolska.org.pl>
Date: Wed, 19 Mar 2014 13:16:53 +0100
Subject: [PATCH] smartxml: Automatically rollback transaction on error thrown

This works for:
- implicit transactions created for transformations run when there is
no transaction in progress
- transactions started by Document.transaction call

It won't work for transactions started by Document.transactionStart.
---
 src/smartxml/smartxml.js      |  7 ++++++-
 src/smartxml/smartxml.test.js | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/smartxml/smartxml.js b/src/smartxml/smartxml.js
index 31faef0..663b332 100644
--- a/src/smartxml/smartxml.js
+++ b/src/smartxml/smartxml.js
@@ -586,7 +586,12 @@ $.extend(Document.prototype, Backbone.Events, {
     transaction: function(callback, context, metadata) {
         var toret;
         this.startTransaction(metadata);
-        toret = callback.call(context);
+        try {
+            toret = callback.call(context);
+        } catch(e) {
+            this.rollbackTransaction();
+            throw e;
+        }
         this.endTransaction();
         return toret;
     },
diff --git a/src/smartxml/smartxml.test.js b/src/smartxml/smartxml.test.js
index c792cf9..d1eaf22 100644
--- a/src/smartxml/smartxml.test.js
+++ b/src/smartxml/smartxml.test.js
@@ -1660,6 +1660,21 @@ describe('smartxml', function() {
                 expect(doc.undoStack.length).to.equal(0, 'nothing to undo');
                 expect(doc.root.contents().length).to.equal(0);
             });
+
+            it('rollbacks and rethrow if error gets thrown', function() {
+                var doc = getDocumentFromXML('<root></root>'),
+                    err = new Error();
+                
+                expect(function() {
+                    doc.transaction(function() {
+                        doc.root.append({tagName: 'div'});
+                        throw err;
+                    });
+                }).to.throw(err);
+
+                expect(doc.root.contents().length).to.equal(0);
+                expect(doc.undoStack.length).to.equal(0);
+            });
         });
 
         describe('Regression tests', function() {
-- 
2.20.1