Form trouble with a relative path php

[conjugateprior]

With rvest 0.2 there seems to be a problem with the following simple looking site

url <- "http://stateoftheunion.onetwothree.net/texts/index.html"
sess <- html_session(url)

form <- html_form(html(url)) %>%.[[1]] %>% set_values(query="freedom") 

This generates the form

<form> '<unnamed>' (GET ../search/search.php)
  <input text> 'query': freedom
  <input submit> 'submit': Search
  <input hidden> 'search': 1

which is fine, but

submit_form(sess, form)

generates

Error: length(url) == 1 is not TRUE 

And it's true. url turns into a three element vector right after the build_url call shown in the screenshot here: