From: "drbrain (Eric Hodel)" <drbrain@...7.net>
Date: 2012-10-27T06:15:03+09:00
Subject: [ruby-core:48357] [ruby-trunk - Bug #7220] StringIO#initialize_copy causes aliasing between the objects


Issue #7220 has been updated by drbrain (Eric Hodel).


IO#dup calls dup(2) and StringIO#dup matches this behavior.

Making IO#dup call open(2) would break backwards compatibility.

How do you propose we implement dup(2) for IO?
----------------------------------------
Bug #7220: StringIO#initialize_copy causes aliasing between the objects
https://bugs.ruby-lang.org/issues/7220#change-31666

Author: brixen (Brian Ford)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 1.9.3p286 (2012-10-12 revision 37165) [x86_64-darwin10.8.0]


Calling StringIO#initialize_copy causes the two objects to share the position, and eof status.

Is this a bug?

sasha:rubinius brian$ irb
1.9.3p286 :001 > require 'stringio'
 => true 
1.9.3p286 :002 > a = StringIO.new "abcdefuq"
 => #<StringIO:0x00000101016a88> 
1.9.3p286 :003 > b = StringIO.new
 => #<StringIO:0x00000101010728> 
1.9.3p286 :004 > b.send :initialize_copy, a
 => #<StringIO:0x00000101010728> 
1.9.3p286 :005 > a.pos
 => 0 
1.9.3p286 :006 > b.pos
 => 0 
1.9.3p286 :007 > b.getc
 => "a" 
1.9.3p286 :008 > a.pos
 => 1 
1.9.3p286 :009 > a.getc
 => "b" 
1.9.3p286 :010 > b.pos
 => 2 
1.9.3p286 :011 > b.read
 => "cdefuq" 
1.9.3p286 :012 > a.eof?
 => true 

Thanks,
Brian


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