Tempfile#unlink changes in Ruby 1.9.1-p152

[Niels Ganser <niels@herimedia.com>]

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Hey everyone,

after updating my Ruby installation recently, I constantly ran into IOErrors
when using rack. After a bit of digging around I could narrow this down to
RewindableInput#make_rewindable, more specifically
lib/rack/rewindable_input.rb:78. After unlinking the tempfile, the IO object
was closed and thus e.g. the @rewindable_io.rewind in line 93 wasn't
possible any more.

I could trace this back to a change in Ruby introduced in revisions 23494
(trunk) and 23537 (branches/ruby_1_9_1). The relevant changes are reproduced
in ruby-core[1] and redmine[2]. As you can see, Tempfile#unlink now calls
#close before actually unlinking the file.

An obvious workaround is attached but surely the whole "if
filesystem_has_posix_semantics?" block should be reworked or this should be
followed up with the ruby core guys. While I'm not exactly sure whether we
can consider closing the IO stream to a file before unlinking it a bug in
itself, Tempfile#unlink now sure is inconsistent with File#unlink. Principle
of least surprise? No, Sir!

What do you guys think?

Best,
Niels

[1] http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/23505
[2] http://redmine.ruby-lang.org/issues/show/1494

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From d960563139192baf39a380055fce85ed5ecde465 Mon Sep 17 00:00:00 2001
From: Niels Ganser <niels@herimedia.com>
Date: Sat, 18 Jul 2009 21:14:21 +0200
Subject: [PATCH] Workaround for Tempfile#unlink change in 1.9.1-p152

Starting with patchlevel 152, Ruby 1.9 closes a Tempfile
upon unlinking it. In such cases we would run into IOErrors
(closed stream) when trying to keep using @rewindable_io
after unlinking it.
---
 lib/rack/rewindable_input.rb |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/rack/rewindable_input.rb b/lib/rack/rewindable_input.rb
index accd96b..b4d1952 100644
--- a/lib/rack/rewindable_input.rb
+++ b/lib/rack/rewindable_input.rb
@@ -74,7 +74,7 @@ module Rack
       @rewindable_io.chmod(0000)
       @rewindable_io.set_encoding(Encoding::BINARY) if @rewindable_io.respond_to?(:set_encoding)
       @rewindable_io.binmode
-      if filesystem_has_posix_semantics?
+      if filesystem_has_posix_semantics? && "#{RUBY_VERSION}.#{RUBY_PATCHLEVEL}" < "1.9.1.152"
         @rewindable_io.unlink
         @unlinked = true
       end
-- 
1.6.0.4