From 6c1a2acea203cb4fdbc331fbb1f6649598db1ab5 Mon Sep 17 00:00:00 2001
From: Geoff McLane <ubuntu@geoffair.info>
Date: Sun, 27 Sep 2015 17:36:57 +0200
Subject: [PATCH] #273 - avoid xhtml doctype flip/flop

---
 src/lexer.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/lexer.c b/src/lexer.c
index 638f72f..8cc2b0d 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -1771,6 +1771,16 @@ Bool TY_(SetXHTMLDocType)( TidyDocImpl* doc )
             TY_(RepairAttrValue)(doc, doctype, sys, GetSIFromVers(X10T));
             lexer->versionEmitted = X10T;
         }
+        else if (lexer->versions & VERS_HTML5)
+        {
+            /*\
+             *  Issue #273 - If still a html5/xhtml5 bit
+             *  existing, that is the 'ConstrainVersion' has
+             *  not eliminated all HTML5, then nothing to do here.
+             *  Certainly do **not** delete the DocType node!
+             *  see: http://www.w3.org/QA/Tips/Doctype
+            \*/
+        }
         else
         {
             if (doctype)