From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-05-17T00:10:56+09:00
Subject: [ruby-core:45084] [ruby-trunk - Bug #6408][Assigned] DelegateClass#eql? and <=> don't work as expected


Issue #6408 has been updated by mame (Yusuke Endoh).

Status changed from Open to Assigned
Assignee set to tenderlovemaking (Aaron Patterson)
Target version set to 3.0

Hello, Aaron

What do you think about Jeremy's opinion?


I'm just wondering but why do you want to delegate #eql? ?
I guess that is because you are inserting Delegate objects
to a Hash.  Such a code is still dangerous even if the
patch is applied:

  require "delegate"
  
  class Foo; end
  class Bar < DelegateClass(Foo); end
  foo = Foo.new
  bar = Bar.new(foo)
  
  p foo.eql?(foo)  #=> true
  p bar.eql?(foo)  #=> true
  p bar.eql?(bar)  #=> false (this returns true with your patch)

  p foo.eql?(bar)  #=> false (this is NOT fixed)

  h = { bar => 42 }
  p h[foo] #=> nil, not 42

I think it is difficult to "fix."

The same holds for #<=>.
You should not sort an Array that includes Delegate objects.

-- 
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Bug #6408: DelegateClass#eql? and <=> don't work as expected
https://bugs.ruby-lang.org/issues/6408#change-26658

Author: tenderlovemaking (Aaron Patterson)
Status: Assigned
Priority: Normal
Assignee: tenderlovemaking (Aaron Patterson)
Category: 
Target version: 3.0
ruby -v: ruby 2.0.0dev (2012-05-06 trunk 35548) [x86_64-darwin11.3.0]


It seems these two methods aren't delegating to the delegate object when compared against itself.

I've attached a patch with tests and a fix.  It seems nobody is the maintainer for delegate.rb (according to the wiki), so if nobody objects, I will apply this patch.


-- 
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