When a rails app is "mounted" at a prefix'd path (ie - mongrel_rails start --prefix=/prefix), the path that is tried to be read by the caching for JS files is wrong.
With caching on, this code...
<%= javascript_include_tag '/dir/file.js', :cache => 'simple' %>
...leads to...
<script src="/prefix/javascripts/simple.js" type="text/javascript"></script>
..which is correct.
However, the first request made prior to the cache file being written attempts to read from..
RAILS_ROOT/public/prefix/dir/file.js
..instead of...
RAILS_ROOT/public/dir/file.js
The file is written, but is empty.
