Handle exception raised from markdown processing

If an exception is raised from the markdown processor, return plain
text to the user.

Author: rouilj

CHANGES.txt

@@ -34,6 +34,8 @@ Fixed:
   url. Attempts to override cheeseshop_url failed. Replace call to
   cheeseshop in docs with raw html and remove references to
   cheeseshop.  (John Rouillard)
+- issue2551093 - return plain text if markdown formatter throws exception
+  (reported by Cedric Krier, fix by John Rouillard)
 
 Features:
 - issue2550522 - Add 'filter' command to command-line

roundup/cgi/templating.py

@@ -1730,7 +1730,11 @@ def markdown(self, hyperlink=1):
         s = self.plain(escape=0, hyperlink=0)
         if hyperlink:
             s = self.hyper_re.sub(self._hyper_repl_markdown, s)
-        return u2s(markdown(s2u(s)))
+        try:
+            s = u2s(markdown(s2u(s)))
+        except Exception:  # when markdown formatting fails return markup
+            return self.plain(escape=0, hyperlink=hyperlink)
+        return s
 
     def field(self, **kwargs):
         """ Render the property as a field in HTML.

test/test_templating.py

@@ -460,8 +460,23 @@ def test_string_markdown_forced_line_break(self):
         self.assertEqual(3, m.count('<br'))
 
     def test_string_markdown_code_block(self):
-        p = StringHTMLProperty(self.client, 'test', '1', None, 'test', u2s(u'embedded code block\n\n```\nline 1\nline 2\n```\n\nnew paragraph'))
-        self.assertEqual(p.markdown().strip().replace('\n\n', '\n'), u2s(u'<p>embedded code block</p>\n<pre><code>line 1\nline 2\n</code></pre>\n<p>new paragraph</p>'))
+        ''' also verify that embedded html is escaped '''
+        p = StringHTMLProperty(self.client, 'test', '1', None, 'test', u2s(u'embedded code block <pre>\n\n```\nline 1\nline 2\n```\n\nnew </pre> paragraph'))
+        self.assertEqual(p.markdown().strip().replace('\n\n', '\n'), u2s(u'<p>embedded code block &lt;pre&gt;</p>\n<pre><code>line 1\nline 2\n</code></pre>\n<p>new &lt;/pre&gt; paragraph</p>'))
+
+    def test_string_markdown_code_block_attribute(self):
+        ''' also verify that embedded html is escaped '''
+        p = StringHTMLProperty(self.client, 'test', '1', None, 'test', u2s(u'embedded code block <pre>\n\n``` python\nline 1\nline 2\n```\n\nnew </pre> paragraph'))
+        m = p.markdown().strip()
+        print(m)
+        if type(self) == MistuneTestCase:
+            self.assertEqual(m.replace('\n\n','\n'), '<p>embedded code block &lt;pre&gt;</p>\n<pre><code class="lang-python">line 1\nline 2\n</code></pre>\n<p>new &lt;/pre&gt; paragraph</p>')
+        elif type(self) == MarkdownTestCase:
+            self.assertEqual(m.replace('\n\n','\n'), '<p>embedded code block &lt;pre&gt;</p>\n<pre><code class="language-python">line 1\nline 2\n</code></pre>\n<p>new &lt;/pre&gt; paragraph</p>')
+        else: # markdown2 doesn't handle attributes with code blocks
+              # so processing it returns original text
+            self.assertEqual(m.replace('\n\n', '\n'), u2s(u'embedded code block &lt;pre&gt;\n``` python\nline 1\nline 2\n```\nnew &lt;/pre&gt; paragraph'))
+
 
 @skip_mistune
 class MistuneTestCase(TemplatingTestCase, MarkdownTests) :