difficult to persist after making changes to part of a hash attribute

[stepheneb]

I'm persisting a hash attribute and I would like to make changes to parts of the hash and persist them -- however making changes to just part of a hash doesn't mark the model as changed.

The only way I found to do this so far is to serialize and un-serialize with json -- which decreases performance.

I am looking at the Modis code and it seems it's not responsible for maintaining the changed state.

A simple example of the issue:

class Book
  include Modis::Model
  attribute :pages, :integer
  attribute :desc, :hash
end


b1 = Book.create!(:pages => 100, :desc => { :a => 'good' })
=> #<Book:0x007ffdd7f74bd0

b1.pages = 99
=> 99

b1.changed?
=> true

b1.save
=> true

b1.changed?
=> false

b1.desc = { :a => 'very good' }
=> {:a=>"very good"}

b1.changed?
=> true

b1.save
=> true

b1.changed?
=> false

b1.desc[:a] = 'super good'
=> "super good"

b1.desc
=> {:a=>"super good"}

b1.changed?
=> false

b1.desc = JSON(b1.desc.to_json)
=> {"a"=>"super good"}

b1.changed?
=> true

[stepheneb]

Ahh ... looking into ActiveModel::Dirty found the solution.

Continuing on from the example above:

b1.save
=> true

b1.changed?
=> false

b1.desc_will_change!
=> {"a"=>"super good"}

b1.desc_change
=> [{"a"=>"super good"}, {"a"=>"super good"}]

b1.desc["a"] = 'mega good'
=> "mega good"

b1.desc_change
=> [{"a"=>"super good"}, {"a"=>"mega good"}]

b1.changed?
=> true