From: eregontp@...
Date: 2015-07-22T08:34:41+00:00
Subject: [ruby-core:70082] [Ruby trunk - Bug #11385] `==` with	bidirectional/cyclic dependency

Issue #11385 has been updated by Benoit Daloze.


Should the result not be **false** instead?
These two instances each have a different @friend and it cannot be determined if they are equal so "false" seems a much safer answer.

Also, this seems inconsistent to how Comparable#== treat such cases:

class Something
  attr_accessor :friend
  def initialize(friend)
    self.friend = friend
  end
  include Comparable
  def <=>(other)
    friend <=> other
  end
end
a = Something.new([])
b = Something.new([a])
a.friend = [b]
p a == b # false (and not true like above!)


----------------------------------------
Bug #11385: `==` with bidirectional/cyclic dependency
https://bugs.ruby-lang.org/issues/11385#change-53498

* Author: Allen Wang
* Status: Rejected
* Priority: Normal
* Assignee: ruby-core
* ruby -v: 2.2.1
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
```ruby
class Something
  attr_accessor :friend
  def initialize(friend)
    self.friend = friend
  end

  def ==(other)
    friend == other.friend
  end
end


a = Something.new([])
b = Something.new([a])
a.friend = [b]

a == b
```

The above code returns true on OS X and Linux, by right it should give me a exception of stack level too deep.

( And on windows I can see the expected exception )

---Files--------------------------------
test.rb (226 Bytes)


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