2

When I clone a simple object in ruby-1.9.2-p290, everything looks OK

class Klass
    attr_accessor :str
end
s1 = Klass.new         #=> #<Klass:0x401b3a38>
s1.str = "Hello"       #=> "Hello"
s2 = s1.clone          #=> #<Klass:0x401b3998 @str="Hello">
s2.str = "Hello world" #=> "Hello world"
s2                     #=> #<Klass:0x00000100977c40 @str="Hello world">
s1                     #=> #<Klass:0x00000100993fa8 @str="Hello">

But when I clone an ActiveRecord object then something strange happens:

I am using the rails 3.1.8. Loading development environment (Rails 3.1.8). When I start the 'rails console'.

ruby-1.9.2-p290 :001 > chair = Chair.new(:code => 'code', :description => 'The Description')
#=> #<Chair id: nil, code: "code", description: "The Description", user_id: nil, created_at: nil, updated_at: nil> 
ruby-1.9.2-p290 :002 > chair_clone = chair.clone
#=> #<Chair id: nil, code: "code", description: "The Description", user_id: nil, created_at: nil, updated_at: nil> 
ruby-1.9.2-p290 :003 > chair_clone.description = "Update description"
#=> "Update description" 
ruby-1.9.2-p290 :004 > chair_clone
#=> #<Chair id: nil, code: "code", description: "Update description", user_id: nil, created_at: nil, updated_at: nil>     
ruby-1.9.2-p290 :005 > chair
#=> #<Chair id: nil, code: "code", description: "Update description", user_id: nil, created_at: nil, updated_at: nil>

Isn't it strange that the description attribute of the original object 'chair' is also updated.
I found the following warning in the http://apidock.com/ruby/Object/clone doc

Change in clone for ActiveRecord objects in ruby-1.9.3

I noticed that cloning an active record object in ruby-1.9.3 and then changing an attribute on the original object will actually change the cloned object as well. This was not the case in ruby-1.9.2.

Is there already a solution available for this issue ?

Thanks in advance for any feedback.

Joost

user1593409
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2 Answers2

4

Instead of using clone use dup like:
...
chair_clone = chair.dup
...

wiseland
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0
u = User.last
u.duplicable? # => true
u2 = u.dup
u2.email = 'wwwww'
u.email # => 'megacoder@rambler.ru'
u2.email # => 'wwwww'
freeze
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