I can't upgrade to grape 0.10

[eguneys]

I use this project as a template, except I use activerecord:

get 'articles' do
  # ActiveRecord::Relation
  articles = Articles.all
  # articles.respond_to?('merge') == true
  present articles, with: ArticlesPresenter
end

This crashes because of this change.

Because the opts parameter is empty:

link :self do |opts|
  "#{base_url(opts)}/api"
end

Though it's not a problem for this project because splines is an array and it doesn't respond_to?('merge').

get do
  splines = Acme::Models::Spline.all
  present Kaminari.paginate_array(splines).page(params[:page]).per(params[:size]), with: Acme::Api::Presenters::SplinesPresenter
end

I can't understand further, please fix this, here's a full stack trace:

NoMethodError:
undefined method `[]' for nil:NilClass
Shared Example Group: "paginated resource" called from ./spec/app/api/article_spec.rb:4
# ./app/presenters/paginated_presenter.rb:33:in `request_url'
# ./app/presenters/paginated_presenter.rb:16:in `block in <module:PaginatedPresenter>'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:80:in `instance_exec'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:80:in `run_link_block'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:68:in `block in compile_links_for'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:66:in `collect'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:66:in `compile_links_for'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:62:in `prepare_links!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/hypermedia.rb:139:in `block in create_links_definition!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/uber-0.0.12/lib/uber/options.rb:80:in `instance_exec'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/uber-0.0.12/lib/uber/options.rb:80:in `proc!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/uber-0.0.12/lib/uber/options.rb:69:in `evaluate_for'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/uber-0.0.12/lib/uber/options.rb:60:in `evaluate'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/binding.rb:107:in `evaluate_option'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/binding.rb:80:in `get'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/binding.rb:37:in `block in compile_fragment'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/binding.rb:100:in `evaluate_option'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/binding.rb:36:in `compile_fragment'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/mapper.rb:64:in `compile_fragment'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/roar-1.0.0/lib/roar/json/hal.rb:64:in `compile_fragment'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/mapper.rb:30:in `serialize_property'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/mapper.rb:22:in `block in serialize'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/mapper.rb:21:in `each'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/mapper.rb:21:in `serialize'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable.rb:41:in `create_representation_with'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/representable-2.1.3/lib/representable/hash.rb:35:in `to_hash'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/dsl/inside_route.rb:200:in `merge'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/dsl/inside_route.rb:200:in `present'
# ./app/api/articles.rb:20:in `block in <class:Articles>'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:47:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:47:in `block in generate_api_method'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:247:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:247:in `run'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:195:in `block in call!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/base.rb:24:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/base.rb:24:in `call!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/base.rb:18:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/base.rb:24:in `call!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/base.rb:18:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/error.rb:27:in `block in call!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/error.rb:26:in `catch'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/error.rb:26:in `call!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/middleware/base.rb:18:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-1.6.0/lib/rack/head.rb:13:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-1.6.0/lib/rack/builder.rb:153:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:196:in `call!'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/endpoint.rb:184:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/route_set.rb:152:in `block in call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/code_generation.rb:96:in `block in recognize'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/code_generation.rb:75:in `optimized_each'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/code_generation.rb:95:in `recognize'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/route_set.rb:141:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/code_generation.rb:96:in `block in recognize'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/code_generation.rb:75:in `optimized_each'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/code_generation.rb:95:in `recognize'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-mount-0.8.3/lib/rack/mount/route_set.rb:141:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/grape-0.10.1/lib/grape/api.rb:102:in `call'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-test-0.6.3/lib/rack/mock_session.rb:30:in `request'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-test-0.6.3/lib/rack/test.rb:244:in `process_request'
# /home/ubuntu/.rvm/gems/ruby-2.1.3/gems/rack-test-0.6.3/lib/rack/test.rb:58:in `get'
# ./spec/app/api/shared_examples/resource.rb:34:in `block (3 levels) in <top (required)>'

[dblock]

Do you have a branch with all your code changes? Happy to help.

[dblock]

Oooohhh wait, check out https://github.com/dblock/grape-with-roar/tree/with-activerecord, I think this is everything you want, no?

[eguneys]

Appreciate the quick response, I've produced the problem in my fork.

[dblock]

splines.page(params[:page]).per(params[:size]) returns an ActiveRecord::Relation, then SplinesPresenter turns that into an Array because it has collection :to_a, extend: SplinePresenter, as: :splines, embedded: true. Your code and the old code are in fact identical as far as the presenter is concerned.

However you're right that because of https://github.com/intridea/grape/pull/784/files it tries to merge the presenter onto body, which causes the presenter to render without any options, and basing that decision only on the check that the representation supports something called merge. It looks pretty iffy, so lets call it a bug.

I opened ruby-grape/grape#890, I am not sure what the best way to implement this, but before we go fixing it we need a spec in Grape that reproduces this exact problem. Would appreciate some help.

[mfunaro]

Apologies if I have caused headaches, I am the one who created that pull request in question. I have been poking around in branch @eguneys created to show the error. I will have to agree that the check on respond_to? 'merge' is a bit flimsy and I must admit that I was thinking about this from the perspective of Grape Entities.

I will continue working with this issue to see if I can come up with a fix for it. I was able to avoid the error in @eguneys branch by changing the respond_to? 'merge to is_a?(Hash) that could be a stop gap for @eguneys to at least upgrade to the newer Grape, however that was completely off the cuff and not tested against anything other than that endpoint.

Again I am sorry if I caused undue headaches and stress.

[dblock]

No stress @mfunaro :)

[mfunaro]

Thinking about the code a bit, what if rather than checking for merge, we simply check if there is an entity_class and if there is something already in the @body?

Something like...

representation = if key
               (@body || {}).merge(key => representation)
             elsif entity_class.present? && @body
               @body.merge(representation)
             end

This makes the assumption, if the user has modified body (either through a previous present or otherwise), they want to merge what has already been modified with what they are now presenting. Is that a safe assumption? I haven't run this through any tests or even made the changes in code, just "thinking out loud" right now.

[dblock]

I opened and am trying to fix ruby-grape/grape#1023

[dblock]

Fixed in ruby-grape/grape#1025, will be in Grape 0.12.0.