From 7531b323b272f1210bd3be00104410dadb4e65e5 Mon Sep 17 00:00:00 2001
From: Neil Fraser <neil.fraser@gmail.com>
Date: Fri, 12 Oct 2018 06:34:23 -0700
Subject: [PATCH] Honour reductions to MAX_UNDO (#2078)
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* Honour reductions to MAX_UNDO

If MAX_UNDO is reduced, we now throw away the extra records in the stack, as opposed to just not growing it anymore.

* shift != unshift

Apparently I need a new brain.

* Ensure MAX_UNDO isn’t negative.
---
 core/workspace.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/workspace.js b/core/workspace.js
index 2454e2ae9..5343968aa 100644
--- a/core/workspace.js
+++ b/core/workspace.js
@@ -523,8 +523,8 @@ Blockly.Workspace.prototype.fireChangeListener = function(event) {
   if (event.recordUndo) {
     this.undoStack_.push(event);
     this.redoStack_.length = 0;
-    if (this.undoStack_.length > this.MAX_UNDO) {
-      this.undoStack_.unshift();
+    while (this.undoStack_.length > this.MAX_UNDO && this.MAX_UNDO >= 0) {
+      this.undoStack_.shift();
     }
   }
   for (var i = 0, func; func = this.listeners_[i]; i++) {