From 4c1a35e34c9cdc8dfd5a2d346ee5c183ab93d11e Mon Sep 17 00:00:00 2001
From: Tim Hunt <T.J.Hunt@open.ac.uk>
Date: Mon, 19 Nov 2012 17:21:00 +0000
Subject: [PATCH] MDL-36571 qtype multichoice: don't corrupt unicode
 characters.
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

It seems that \s includes non-breaking space, and the typical one-byte
representation of that is the same as some parts of multibyte unicode
characters. Therefore, you need to include the u modifer on the regular
expressions.

Also, remove any number of <br /> at the end of the answer.

Thanks to Joseph Rézeau and Jean-Michel Vedrine for working out what the
problem was, and how to fix it.
---
 question/type/multichoice/question.php            | 8 ++++----
 question/type/multichoice/tests/question_test.php | 2 ++
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/question/type/multichoice/question.php b/question/type/multichoice/question.php
index afca6a47740..8dd70861160 100644
--- a/question/type/multichoice/question.php
+++ b/question/type/multichoice/question.php
@@ -126,10 +126,10 @@ abstract class qtype_multichoice_base extends question_graded_automatically {
     }
 
     public function make_html_inline($html) {
-        $html = preg_replace('~\s*<p>\s*~', '', $html);
-        $html = preg_replace('~\s*</p>\s*~', '<br />', $html);
-        $html = preg_replace('~<br />$~', '', $html);
-        return $html;
+        $html = preg_replace('~\s*<p>\s*~u', '', $html);
+        $html = preg_replace('~\s*</p>\s*~u', '<br />', $html);
+        $html = preg_replace('~(<br\s*/?>)+$~u', '', $html);
+        return trim($html);
     }
 }
 
diff --git a/question/type/multichoice/tests/question_test.php b/question/type/multichoice/tests/question_test.php
index fe5ba514efe..cbd3827f5ea 100644
--- a/question/type/multichoice/tests/question_test.php
+++ b/question/type/multichoice/tests/question_test.php
@@ -147,6 +147,8 @@ class qtype_multichoice_single_question_test extends advanced_testcase {
         $this->assertEquals("Frog<br />XXX <img src='http://example.com/pic.png' alt='Graph' />",
                 $mc->make_html_inline(" <p> Frog </p> \n\r
                     <p> XXX <img src='http://example.com/pic.png' alt='Graph' /> </p> "));
+        $this->assertEquals('Frog', $mc->make_html_inline('<p>Frog</p><p></p>'));
+        $this->assertEquals('Frog<br />†', $mc->make_html_inline('<p>Frog</p><p>†</p>'));
     }
 }
 
-- 
2.43.0