From: "Adrián De la Cruz" <adrian@...>
Date: 2009-10-31T14:11:39+09:00
Subject: I'm having a little issue with YAML

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Hi guys,

I'm seeing some strange behavior with YAML serialization/deserialization
and would like someone to explain what's going on with this, if
possible.

I attached two files that you can run with:
spec battle_spec.rb (this one fails)
spec battle2_spec.rb (this one doesn't fail)

The difference between the two, is just a character in the name of an
instance variable.

The source code is very simple. It has three classes to represent a
nested structure:

A Battlefield might contain many teams, a Team might contain many
Warriors. In my sample it's just one of each, to keep it simple.


The problem is that, the Team @members are nullified in some cases.

battle_spec.rb shows a case where Team#members is nil.
battle2_spec.rb shows a case where Team#members is not nil (just
changing a character in a instance variable name, the one that makes the
Battlefield accessible for a Team [a var to point to its parent]).

I'm kinda new to this testing stuff, maybe I'm doing something wrong, if
that's the case, I'll be glad to hear any advice or pointers.

If you need more info, I'll be glad to provide it.


Best regards,
V=C3=ADctor Adri=C3=A1n.

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Content-Disposition: attachment; filename="battle_spec.rb"
Content-Type: application/x-ruby; name="battle_spec.rb"
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# -*- coding: utf-8 -*-
require 'rubygems'
require 'spec'

class Battlefield
  attr_accessor :teams
  def initialize
    @teams = []
  end
  def add_team(team)
    @teams << team
    team.bparent = self
  end
end

class Team
  attr_accessor :members, :bparent
  def initialize
    @members = []
    @bparent = nil
  end
  def add_member(child)
    @members << child
    child.team = self
  end
end

class Warrior
  attr_accessor :team
  def initialize
    @team = nil
  end
end

describe Battlefield do
  describe Team do
    it "should have members" do
      w = Warrior.new
      t = Team.new
      t.add_member(w)
      b = Battlefield.new
      b.add_team(t)
      
      y = YAML.load(b.to_yaml)
      y.teams.first.members.should_not be_nil
    end
  end
end

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Content-Disposition: attachment; filename="battle2_spec.rb"
Content-Type: application/x-ruby; name="battle2_spec.rb"
Content-Transfer-Encoding: 7bit

# -*- coding: utf-8 -*-
require 'rubygems'
require 'spec'

class Battlefield
  attr_accessor :teams
  def initialize
    @teams = []
  end
  def add_team(team)
    @teams << team
    team.parent = self
  end
end

class Team
  attr_accessor :members, :parent
  def initialize
    @members = []
    @parent = nil
  end
  def add_member(child)
    @members << child
    child.team = self
  end
end

class Warrior
  attr_accessor :team
  def initialize
    @team = nil
  end
end

describe Battlefield do
  describe Team do
    it "should have members" do
      w = Warrior.new
      t = Team.new
      t.add_member(w)
      b = Battlefield.new
      b.add_team(t)
      
      y = YAML.load(b.to_yaml)
      y.teams.first.members.should_not be_nil
    end
  end
end

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