From b1343319564189da6924eacb21ba37ef05cdb935 Mon Sep 17 00:00:00 2001
From: Mark Jaquith <markjaquith@git.wordpress.org>
Date: Thu, 28 Mar 2013 02:49:55 +0000
Subject: [PATCH] Make sure that the ID of the right revision is not less than
 the ID of the left revision

see #23497

git-svn-id: https://develop.svn.wordpress.org/trunk@23832 602fd350-edb4-49c9-b593-d223f7449a82
---
 wp-admin/includes/ajax-actions.php | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/wp-admin/includes/ajax-actions.php b/wp-admin/includes/ajax-actions.php
index 66863a356b..74c48057c9 100644
--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -2130,6 +2130,13 @@ function wp_ajax_revisions_data() {
 	if ( 0 != $single_revision_id ) {
 		$right_revision = get_post( $single_revision_id );
 
+	// make sure the right revision is the most recent
+	if ( $compare_two_mode && $right_revision->ID < $left_revision->ID ) {
+		$temp = $left_revision;
+		$left_revision = $right_revision;
+		$right_revision = $temp;
+	}
+
 		$linesadded=0;
 		$linesdeleted=0;