From da095cdfe95a4d83b12d7791236a4dcee21b4c15 Mon Sep 17 00:00:00 2001
From: Kevin Sawicki & Nathan Sobo <kevin+nathan@github.com>
Date: Fri, 4 Jan 2013 13:01:23 -0700
Subject: [PATCH] Leave the undo stack intact when aborting empty transactions

---
 spec/app/undo-manager-spec.coffee | 9 +++++++++
 src/app/undo-manager.coffee       | 6 ++++++
 2 files changed, 15 insertions(+)

diff --git a/spec/app/undo-manager-spec.coffee b/spec/app/undo-manager-spec.coffee
index 32f141667..df1c9c690 100644
--- a/spec/app/undo-manager-spec.coffee
+++ b/spec/app/undo-manager-spec.coffee
@@ -157,6 +157,15 @@ describe "UndoManager", ->
         undoManager.redo()
         expect(buffer.getText()).toBe '12'
 
+  describe "abort", ->
+    it "does not affect the undo stack when the current transaction is empty", ->
+      buffer.setText('')
+      buffer.append('1')
+      buffer.transact()
+      buffer.abort()
+      expect(buffer.getText()).toBe '1'
+      buffer.undo()
+      expect(buffer.getText()).toBe ''
 
   describe "when a `do` operation throws an exception", ->
     it "clears the stack", ->
diff --git a/src/app/undo-manager.coffee b/src/app/undo-manager.coffee
index e910bc819..aa025668b 100644
--- a/src/app/undo-manager.coffee
+++ b/src/app/undo-manager.coffee
@@ -40,12 +40,18 @@ class UndoManager
 
   commit: ->
     @undoHistory.push(@currentTransaction) if @currentTransaction?.length
+    empty = @currentTransaction.length is 0
+    @undoHistory.push(@currentTransaction) unless empty
     @currentTransaction = null
+    not empty
 
   abort: ->
     @commit()
     @undo()
     @redoHistory.pop()
+    if @commit()
+      @undo()
+      @redoHistory.pop()
 
   undo: (editSession) ->
     try