hadley/httr — pull request #147 by craigcitro (2014-09-10 18:03:40+00:00)
Title: Encoding change for JSON bodies

Between 0.4 and 0.5, something has changed about the way JSON bodies get encoded -- a list like

ls <- list(f = "hi")

was previously encoded as

{"f": "hi"}

but is now being encoded as

{"f": ["hi"]}

this of course wreaks havoc on any API that doesn't differentiate a string and a list with one string. in particular, it's causing failures in `bigrquery` as discovered by @deflaux.

i'm still digging to figure out whether the change was on the `httr` side or the `jsonlite` side.