Issue #11015 has been updated by Nobuyoshi Nakada.

Description updated

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Bug #11015: IO.copy_stream does not advance Tempfile destination
https://bugs.ruby-lang.org/issues/11015#change-51970

* Author: Charles Nutter
* Status: Closed
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin14]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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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 `copy_stream`:

~~~ruby
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.



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