IO.copy_stream does not advance Tempfile destination
The following script, reported to JRuby in https://github.com/jruby/jruby/issues/2762, shows that MRI does not advance the position of a
Tempfile when using
require "stringio" require "tempfile" file = Tempfile.new('foo') IO.copy_stream(StringIO.new('foo'), file) file.eof? #=> false (it's on the beginning)
Other types of streams leave the destination where it is after the copy, so I believe this is a bug.