I am getting the same error with
arcanist c58f1b9a2507488b2152473dd1f0bbc7e99c09c1 (29 Apr 2016) libphutil 0709cd5cfc2616c29104387de6dde3de1db7fa32 (2 May 2016)
and
svn, version 1.9.4 (r1740329) compiled Apr 28 2016, 01:15:57 on x86_64-apple-darwin15.4.0