On Jan 5, 2014, at 11:46 PM, Keenan Brock <kee...@thebrocks.net> wrote:
> Hello All,
>
> Currently, `serialized` columns get save to the database whether they are
> changed or not. [Github][1]. Since the serialized columns can be modified
> inline, `Dirty` is not used. This behavior introduces too much database
> overhead for us, so I'd like to patch that code right out of there.
>
> ## Having trouble extending ActiveRecord
>
> `ActiveRecord::Base.ancestors` returns `ActiveRecord::Core` before
> `ActiveRecord::AttributeMethods::Dirty`, so the methods in `Core` take
> precedence over those in `Dirty`.
>
> I was thinking `Dirty` overrides the behavior of `Core` and should have
> higher precedence. This would allow `@changed_attribtues` to move from `Core`
> to `Dirty`.
>
> Is there history to this decision? Or is it even possible to change this? (I
> mean from both technically, as well as logistically changing something so
> core to the code.)
>
> ## Changing the way `Dirty` is implemented.
>
> I played around with storing the original values for an attribute, rather
> than just the values that have been changed. [Github][2] Only cloning/storing
> `@original_values` on attribute access keeps the code as close to the current
> `@changed_attributes` implementation. It not only works with serialized
> variables, but code like `model.field.gsub!('a','b')`, without requiring
> `field_will_change!`
Cloning fails in exciting and (likely) unexpected ways when the serialized
value is deeper than one level:
irb: hash = { a: [1,2,3], b: [4,5,6] }
===> {:a=>[1, 2, 3], :b=>[4, 5, 6]}
irb: hash2 = hash.clone
===> {:a=>[1, 2, 3], :b=>[4, 5, 6]}
irb: hash2[:a] << 'baz'
===> [1, 2, 3, "baz"]
irb: hash
===> {:a=>[1, 2, 3, "baz"], :b=>[4, 5, 6]}
The only way I’ve found to reliably deep-clone objects is to chain together
Marshal.dump and Marshal.load, but that’s almost *got* to be terrible for
performance.
—Matt Jones
--
You received this message because you are subscribed to the Google Groups "Ruby
on Rails: Core" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rubyonrails-core+unsubscr...@googlegroups.com.
To post to this group, send email to rubyonrails-core@googlegroups.com.
Visit this group at http://groups.google.com/group/rubyonrails-core.
For more options, visit https://groups.google.com/groups/opt_out.
