#1305 has_one dependent nullify deletes associated object on change - Ruby on Rails

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#1305 ✓resolved

has_one dependent nullify deletes associated object on change

Reported by Chris Elledge | October 30th, 2008 @ 09:36 PM | in 2.x

Using Rails 2.1.1

class User < ActiveRecord::Base
  has_one :device, :dependent => :nullify
end

u = User.find(1)
u.device = Device.find(1)
u.device = Device.new
Device.find(1)
  ActiveRecord::RecordNotFound: Couldn't find Device with ID=1

From the description of :dependent => :nullify it doesn't sound like it should be deleting the device that was previously assigned. It doesn't do this if :dependent is not set.

Why should :dependent => :nullify delete objects like this when the default setting doesn't?

Comments and changes to this ticket

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Gregory Man November 10th, 2008 @ 02:32 PM
+1 I have same issue.
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labria November 10th, 2008 @ 05:24 PM
Added a test to show the problem.
- has_one_bug_test.diff 1.2 KB
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labria November 10th, 2008 @ 05:41 PM
I have found the source of it. The HasOneAssociation has a "replace" method. Inside it, it checks the dependent? method of the association, and if it finds it to be true, it destroys the old associated object.
```
unless @target.nil? || @target == obj
  if dependent? && !dont_save
    @target.destroy unless @target.new_record?
    @owner.clear_association_cache
  else
    @target[@reflection.primary_key_name] = nil
    @target.save unless @owner.new_record? || @target.new_record?
  end
end
```
The problem is: the "dependent?" method only checks this:
```
def dependent?
  @reflection.options[:dependent]
end
```
So, no matter what kind of :dependent key was used, it destroys the record. I'll try to add tests and fix the problem.
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labria November 10th, 2008 @ 05:57 PM
- Tag changed from “has_one, nullify” to “has_one, nullify, patch”
Here's the patch fixing the problem. What still remains is the fact that :destroy or :delete do not actually matter, each time #destroy is called.
- has_one_bug_patch_with_test.diff 2.3 KB
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labria November 10th, 2008 @ 07:10 PM
Fixed the case when destroy was called instead of delete. Tests included.
- has_one_bug_patch_with_test_and_delete_or_destroy_option.diff 5.8 KB
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Max Lapshin November 10th, 2008 @ 08:14 PM
+1 This should be fixed.
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Gregory Man November 11th, 2008 @ 08:51 AM
+1 patch work for me
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Roy Man November 11th, 2008 @ 08:59 AM
+1 it works for me
Pratik November 14th, 2008 @ 10:59 PM
- Assigned user set to “Pratik”
Pratik March 6th, 2009 @ 06:55 PM
- State changed from “new” to “incomplete”
I don't think the tests should be using stubbing here. Account has the following callback :
```
  before_destroy do |account|
    if account.firm
      Account.destroyed_account_ids[account.firm.id] << account.id
    end
    true
  end
```
So that can be used here.
Pratik March 6th, 2009 @ 07:10 PM
Nevermind, I'll make the change and commit.

Thanks.
Repository March 6th, 2009 @ 07:13 PM
- State changed from “incomplete” to “resolved”
(from [984bc7a614852944808739fae09a654b6e62872e]) Ensure replacing has_one associations respects the supplied :dependent option. [#1305 state:resolved]

Signed-off-by: Pratik Naik pratiknaik@gmail.com http://github.com/rails/rails/co...