From d51e1162981416933ae01a5eea8b4ca39c116d55 Mon Sep 17 00:00:00 2001
From: Andrew Ozz <azaozz@git.wordpress.org>
Date: Sat, 20 Feb 2016 19:55:03 +0000
Subject: [PATCH] TinyMCE: fix the regex that removes spaces from empty
 paragraphs. Was causing problems when wpautop is disabled and there are many
 U+00A0 chars between the opening `<p>` and an inline tag. These chars are
 inserted by the browsers to maintain consecutive spaces typed by the users in
 contentEditable.

Fixes #35890.

git-svn-id: https://develop.svn.wordpress.org/trunk@36597 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/js/tinymce/plugins/wordpress/plugin.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/js/tinymce/plugins/wordpress/plugin.js b/src/wp-includes/js/tinymce/plugins/wordpress/plugin.js
index 13ef3af059..7a811404cd 100644
--- a/src/wp-includes/js/tinymce/plugins/wordpress/plugin.js
+++ b/src/wp-includes/js/tinymce/plugins/wordpress/plugin.js
@@ -117,7 +117,15 @@ tinymce.PluginManager.add( 'wordpress', function( editor ) {
 			}
 
 			// Remove spaces from empty paragraphs.
-			event.content = event.content.replace( /<p>(?:&nbsp;|\u00a0|\uFEFF|\s)+<\/p>/gi, '<p><br /></p>' );
+			// Avoid backtracking, can freeze the editor. See #35890.
+			// (This is also quite faster than using only one regex.)
+			event.content = event.content.replace( /<p>([^<>]+)<\/p>/gi, function( tag, text ) {
+				if ( /^(&nbsp;|\s|\u00a0|\ufeff)+$/i.test( text ) ) {
+					return '<p><br /></p>';
+				}
+
+				return tag;
+			});
 		}
 	});