Fix to make has_one/has_many :dependent behaviour consistent (my first patch)

rubyonrails-core
1

I've just submitted my first patch, and I'd love to get some feedback on it. This patching Rails thing is a bit daunting if you haven't done it before! Not sure if I'm on the right track.

http://dev.rubyonrails.org/ticket/9129

From the description:

A has_one or has_many relationship with :dependent set either :nullify will incorrectly destroy the associated objects when the association is reassigned or set to nil. Instead, the associated objects' foreign keys should be nullified, as they are when the parent object is destroyed.

For example, given this association:

  class Fred     has_one :george, :dependent => :nullify   end

The following will cause george to be destroyed.

  fred = Fred.create   george = George.create(:fred_id => fred)

  fred.george = nil

The issue also extends to :dependent => :delete and :dependent => :delete_all. Associated objects are destroyed rather than deleted when the association is reassigned.

The attached patch fixes this issue and makes :dependent behaviour consistent in all circumstances the I can think of.

Cheers,

Pete Yandell

2

D'oh! And I just realised I made a typo in the first line of the description. It should read:

  A has_one or has_many relationship with :dependent set

It's been a long day.

Pete Yandell

3

Hey Pete,

Looks like a good patch, but I think they're already discussing the issue here:

http://dev.rubyonrails.org/ticket/7309

It certainly seems to cover some of the same ground (must admit I haven't looked into it in too much detail). Maybe check that ticket out and see if there's anything to add to it from your patch?

Cheers, Chris

4

Saw that, but it only addresses has_many relationships, and changes the default behaviour when :dependent isn't set in a way that might break things.

Thanks for reminding me of that though...I'll at least add some links between the tickets.

Pete Yandell