Decorating nil object

[kalashnikovisme]

Discussion

What should we do with nil-object decorating? There are 3 approaches:

1. Return just nil
2. Decorate nil object
3. Raise error

I've implemented the first approach here. Waiting for your opinion 🙂

What's changed for tramway drivers?

Before

user = nil
UserDecorator.decorate user # => UserDecorator#object

After

user = nil
UserDecorator.decorate user # => nil

[haukot]

I think 1 is okay, but it would be better to check how popular decoration libraries (e.g., draper) are working, and whether people are raising issues about having problems with them.

Probably, it would be good if this behavior could be easily redefined in inherited decorators.

[kalashnikovisme]

@haukot what about options for this thing, of course, it will be implemented later.

[moshinaan]

@kalashnikovisme in which cases u can get nil for decorating?

[kalashnikovisme]

@moshinaan example:

class Post < ActiveRecord::Base
  belongs_to :user, optional: true
end

class PostDecorator < Tramway::BaseDecorator
  def user
    UserDecorator.decorate object.user
  end
end

in the future, there will be something like this

class PostDecorator < Tramway::BaseDecorator
  belongs_to :user, decorator: UserDecorator
end

So, this case takes its place 🙂

[kalashnikovisme]

What about draper working with nil objects?

Draper uses option 2 - decorating nil objects, and I don't like it in the case of decorating ActiveRecord models. I think that replacing ActiveRecord object with a decorated object should be inconspicuous in controllers. So, the behavior of decorated objects should be similar to the ActiveRecord object as much as possible.

What about active_decorator working with nil objects?

ActiveDecorator uses option 1. But it's not an example, because ActiveDecorator decorates all ActiveRecord objects by default. But if ActiveRecord object is nil, the decorated object is nil too (or maybe decoration does not happen).

@haukot what do you think?