From: Markus Schirp <mbj@...>
Date: 2008-12-16T04:42:34+09:00
Subject: [ruby-core:20586] StringIO bug?

Hello,

Im not shure weather this is the correct place to do bug reports.
If I am not at the correct place here, pls give me a pointer to the correct
location, and sry for the noise!

After unit testing some IO code, using stringio and variable io chunk
size, i found this unexpected behaviour: (stripped down)

####################### Begin Code
require 'stringio'

#disfunctional
io = StringIO.new("123456789")
acc = Array.new
buff = String.new
until(io.eof?)
  io.read(1,buff)
  p buff
  acc << buff
  p acc
end

#functional
io = StringIO.new("123456789")
acc = Array.new
until(io.eof?)
  buff = String.new
  io.read(1,buff)
  p buff
  acc << buff
  p acc
end
######################### End Code

The only difference here is the position of buff = String.new

On all tested plattforms the code prints as follows:

"1"
["1"]
"2"
["2", "2"]
"3"
["3", "3", "3"]
"4"
["4", "4", "4", "4"]
"5"
["5", "5", "5", "5", "5"]
"6"
["6", "6", "6", "6", "6", "6"]
"7"
["7", "7", "7", "7", "7", "7", "7"]
"8"
["8", "8", "8", "8", "8", "8", "8", "8"]
"9"
["9", "9", "9", "9", "9", "9", "9", "9", "9"]
"1"
["1"]
"2"
["1", "2"]
"3"
["1", "2", "3"]
"4"
["1", "2", "3", "4"]
"5"
["1", "2", "3", "4", "5"]
"6"
["1", "2", "3", "4", "5", "6"]
"7"
["1", "2", "3", "4", "5", "6", "7"]
"8"
["1", "2", "3", "4", "5", "6", "7", "8"]
"9"
["1", "2", "3", "4", "5", "6", "7", "8", "9"]

Plattforms: 
Gentoo/x86 (-O2 -fomit-frame-pointer, nothing special):
- 1.8.6 (2008-08-11 patchlevel 287) [i686-linux]
- ruby 1.9.1 (2008-12-16 revision 20768) [i686-linux]
Ubuntu8.10/x86_64:
  2007-09-24 patchlevel 111 

Pls inform me if you need additional information.
-- 
Markus Schirp
Seonic IT-Systems GbR
Anton Shatalov & Markus Schirp
Altenessenerstra�e 50
D-45141 Essen
www.seonic.net
info@seonic.net