Comment 22 for bug 1394403

To reproduce (s. attachment):

vhost bla.conf (requires a2enmod proxy_http)
    enables RewriteEngine/RewriteLogging and Proxy
   DocumentRoot /var/www/bla

RewriteRule ^(.*)$$1 [P]

no other files in /var/www/bla/

request / (as in attached
$ (printf "GET / HTTP/1.0\r\nHost: bla\r\n\r\n"; sleep 1) | netcat localhost 80

in the ErrorLog (/var/log/apache2/bla_error.log) you can see that after the first
  go-ahead with proxy request proxy: [OK]
mod_rewrite is called a second time for the same request, but this time
with /index.html instead of just /
This is from mod_dir not honoring the final decision of mod_rewrite ([P]).