Issue with route('')

[mithrandi]

The documentation seems to indicate that route('') and route('/') should mean the same thing, and in fact the '' version seems to make more sense to me. However, it doesn't appear to actually work, as this gist demonstrates: https://gist.github.com/mithrandi/d72ff26f86de69cdb40e

You can run this with twistd -n web --class resource.Root. Trying to visit /foo/ results in the following traceback:

2015-09-22 19:03:11+0200 [HTTPChannel,1,127.0.0.1] Unhandled Error
        Traceback (most recent call last):
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/web/server.py", line 234, in render
            body = resrc.render(self)
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/web/util.py", line 139, in render
            self.d.addCallback(self._cbChild, request).addErrback(
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/internet/defer.py", line 317, in addCallback
            callbackKeywords=kw)
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/internet/defer.py", line 306, in addCallbacks
            self._runCallbacks()
        --- <exception caught here> ---
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/internet/defer.py", line 588, in _runCallbacks
            current.result = callback(current.result, *args, **kw)
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/web/util.py", line 145, in _cbChild
            request.render(resource.getChildForRequest(child, request))
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/twisted/web/server.py", line 234, in render
            body = resrc.render(self)
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/txspinneret/resource.py", line 183, in render
            result = self._wrappedResource.render(request)
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/txspinneret/route.py", line 238, in render
            result, segments = self._matchRoute(request, [])
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/txspinneret/route.py", line 229, in _matchRoute
            matches, remaining = route(request, segments)
          File "/home/mithrandi/deployment/virtualenvs/tempenv-2c7834670678/local/lib/python2.7/site-packages/txspinneret/route.py", line 113, in _matchRoute
            if components[0] == '/':
        exceptions.IndexError: string index out of range

Funnily enough, the same happens if you try to visit /foo. Changing the route matcher to route('/') fixes both exceptions (the former returning the expected string, and the latter returning 404, all as expected).

[mithrandi]

Edited the gist slightly to demonstrate both working and broken cases at the same time; fetching /working/ should work, and fetching /broken/ produces a traceback like the above.