From 6258ed501e5b751d108b46ce70530ca9776811eb Mon Sep 17 00:00:00 2001
From: Jack Bird <jackbird050@gmail.com>
Date: Tue, 18 Jul 2023 19:19:56 +0100
Subject: [PATCH] updated undo command to only track when a command changes the
 tree

---
 src/js/sandbox/index.js | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/js/sandbox/index.js b/src/js/sandbox/index.js
index 15a323d7..8b8de6c9 100644
--- a/src/js/sandbox/index.js
+++ b/src/js/sandbox/index.js
@@ -67,7 +67,8 @@ var Sandbox = Backbone.View.extend({
 
   initGitShim: function(options) {
     this.gitShim = new GitShim({
-      beforeCB: this.beforeCommandCB.bind(this)
+      beforeCB: this.beforeCommandCB.bind(this),
+      afterCB: this.afterCommandCB.bind(this)
     });
   },
 
@@ -113,12 +114,21 @@ var Sandbox = Backbone.View.extend({
   },
 
   beforeCommandCB: function(command) {
+    this._treeBeforeCommand = this.mainVis.gitEngine.printTree();
+  },
+
+  afterCommandCB: function(command) {
     this.pushUndo();
   },
 
   pushUndo: function() {
+    let currentTree = this.mainVis.gitEngine.printTree();
+    if(currentTree === this._treeBeforeCommand) {
+      return;
+    }
+
     // go ahead and push the three onto the stack
-    this.undoStack.push(this.mainVis.gitEngine.printTree());
+    this.undoStack.push(this._treeBeforeCommand);
   },
 
   undo: function(command, deferred) {