Internal error on preview when having an empty heading

[robert@…]

To reproduce, go on the sandbox, edit, at the bottom of the textarea, just click on the "Heading" icon, an preview.

Here is the traceback:

Oops...
Trac detected an internal error: 
string index out of rangeIf you think this really should work and you can reproduce it. Then you should consider to report this problem to the Trac team. 

Go to http://trac.edgewall.com/ and create a new ticket where you describe the problem, how to reproduce it. Don't forget to include the python traceback found below. 

TracGuide — The Trac User and Administration Guide 

Python traceback
Traceback (most recent call last):
  File "/usr/lib/python2.3/site-packages/trac/ModPythonHandler.py", line 200, in handler
    core.dispatch_request(mpr.path_info, mpr, env)
  File "/usr/lib/python2.3/site-packages/trac/core.py", line 453, in dispatch_request
    module.run(req)
  File "/usr/lib/python2.3/site-packages/trac/Module.py", line 46, in run
    self.render(req)
  File "/usr/lib/python2.3/site-packages/trac/Wiki.py", line 148, in render
    self._render_editor(req, pagename, 1)
  File "/usr/lib/python2.3/site-packages/trac/Wiki.py", line 266, in _render_editor
    info['page_html'] = wiki_to_html(page.text, req.hdf, self.env, self.db)
  File "/usr/lib/python2.3/site-packages/trac/WikiFormatter.py", line 619, in wiki_to_html
    Formatter(hdf, env, db, absurls).format(wikitext, out)
  File "/usr/lib/python2.3/site-packages/trac/WikiFormatter.py", line 596, in format
    result = re.sub(rules, self.replace, line)
  File "/usr/lib/python2.3/sre.py", line 143, in sub
    return _compile(pattern, 0).sub(repl, string, count)
  File "/usr/lib/python2.3/site-packages/trac/WikiFormatter.py", line 67, in replace
    return getattr(self, '_' + itype + '_formatter')(match, fullmatch)
  File "/usr/lib/python2.3/site-packages/trac/WikiFormatter.py", line 385, in _heading_formatter
    if anchor[0].isdigit():
IndexError: string index out of range

[Christopher Lenz]

This is already fixed in trunk. See #1224 and #1367.